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Becker, Felix [Verfasser], and Oliver [Akademischer Betreuer] Paul. "Miniaturized force/moment transducers for instrumented teeth." Freiburg : Universität, 2020. http://d-nb.info/1211956806/34.
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Hsia, Wei-Kung 1958. "DOUBLE ANGLE CONNECTION MOMENTS (RICHARD EQUATION, PRYING FORCE, BEAM-LINE THEORY, MOMENT ROTATION CURVE)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/291892.
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Whitfield, Cindy Carol. "Steady and Unsteady Force and Moment Data on a DARPA2 Submarine." Thesis, Virginia Tech, 1999. http://hdl.handle.net/10919/34333.
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Steady and unsteady force and moment experiments were conducted in the Virginia Tech Stability wind tunnel using the Dynamic Plunge-Pitch-Roll (DyPPiR) model mount to perform rapid time-dependent,high-excursion maneuvers. The experiments were performed for a DARPA2 submarine model using three widely spaced 2-force-component loadcells and three tri-axial accelerometers to extract the aerodynamic loads.The DARPA2 model was tested with different body configurations in two different test sections. The body configurations for both the steady and unsteady experiments were the bare body hull, body with sail, body with stern appendages, and body with sail and stern appendages. Tests were done using trips on the bow and sail and with no trips. The bare hull configuration with no trips was the only body configuration tested in the six-foot-square test section with solid walls. All body configurations were tested in the six-foot-square test section with slotted walls that were used to reduce the blockage effects produced by the DyPPiR and model.
The steady experiments were performed over a range of angles of attack and roll positions. Data were acquired through the series of angles the body encountered during the unsteady testing (-26° < ± <+26° ). The data for the tripped bare hull gave symmetric results while the data acquired for the bare hull with no trips did not. In the unsteady experiments the model was pitched in ramp maneuvers about the 1/4 chord location of the sail from 0° to -25° and from +25° to 0° in 0.3 seconds. Sine wave maneuvers at 3 Hz were also performed, plunging the model up and down with an amplitude of ±0.375 inches. The steady data agreed within uncertainties with previous data that were limited to the David Taylor Research Center (DTRC). There was a higher level of confidence in the steady data taken with trips due to the symmetry of the data. Effects of the sail and/or stern appendages were studied using the steady and unsteady data, but no quantitative value could be calculated due to the uncertainties. The unsteady data
were modeled with a quasi-steady time-lag model, and all the unsteady data were found to lead the quasi-steady data. The unsteady data did have oscillations, but the overall aerodynamic trend was still present. The uncertainties were too large to discuss effects of any appendages, however.
Master of Science
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Johnson, Curtis Mathias. "A comparison of Reduced Beam Section moment connection and Kaiser Bolted Bracket® moment connections in steel Special Moment Frames." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/36233.
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Master of ScienceDepartment of Architectural Engineering and Construction Science
Kimberly W. Kramer
Of seismic steel lateral force resisting systems in practice today, the Moment Frame has most diverse connection types. Special Moment frames resist lateral loads through energy dissipation of the inelastic deformation of the beam members. The 1994 Northridge earthquake proved that the standard for welded beam-column connections were not sufficient to prevent damage to the connection or failure of the connection. Through numerous studies, new methods and standards for Special Moment Frame connections are presented in the Seismic Design Manual 2nd Edition to promote energy dissipation away from the beam-column connection. A common type of SMF is the Reduce Beams Section (RBS). To encourage inelastic deformation away from the beam-column connection, the beam flange’s dimensions are reduced a distance away from the beam-column connection; making the member “weaker” at that specific location dictating where the plastic hinging will occur during a seismic event. The reduction is usually taken in a semi-circular pattern. Another type of SMF connection is the Kaiser Bolted Bracket® (KBB) which consists of brackets that stiffen the beam-column connection. KBB connections are similar to RBS connections as the stiffness is higher near the connection and lower away from the connection. Instead of reducing the beam’s sectional properties, KBB uses a bracket to stiffen the connection. The building used in this parametric study is a 4-story office building. This thesis reports the results of the parametric study by comparing two SMF connections: Reduced Beam Section and Kaiser Bolted Brackets. This parametric study includes results from three Seismic Design Categories; B, C, and D, and the use of two different foundation connections; fixed and pinned. The purpose of this parametric study is to compare member sizes, member forces, and story drift. The results of Seismic Design Category D are discussed in depth in this thesis, while the results of Seismic Design Category B and C are provided in the Appendices.
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Nanou, Katerina. "Design of open cold rolled sections under axial force and bending moment." Thesis, Imperial College London, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324988.
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Castori, Giulia. "Interaction between axial force, shear and bending moment in reinforced concrete elements." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2015. http://amslaurea.unibo.it/8519/.
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Il collasso di diverse colonne, caratterizzate da danneggiamenti simili, quali ampie fessure fortemente inclinate ad entrambe le estremità dell’elemento, lo schiacciamento del calcestruzzo e l’instabilità dei ferri longitudinali, ha portato ad interrogarsi riguardo gli effetti dell’interazione tra lo sforzo normale, il taglio ed il momento flettente.
Lo studio è iniziato con una ricerca bibliografica che ha evidenziato una sostanziale carenza nella trattazione dell’argomento.
Il problema è stato approcciato attraverso una ricerca di formule della scienza delle costruzioni, allo scopo di mettere in relazione lo sforzo assiale, il taglio ed il momento; la ricerca si è principalmente concentrata sulla teoria di Mohr.
In un primo momento è stata considerata l’interazione tra solo due componenti di sollecitazione: sforzo assiale e taglio. L’analisi ha condotto alla costruzione di un dominio elastico di taglio e sforzo assiale che, confrontato con il dominio della Modified Compression Field Theory, trovata tramite ricerca bibliografica, ha permesso di concludere che i risultati sono assolutamente paragonabili.
L’analisi si è poi orientata verso l’interazione tra sforzo assiale, taglio e momento flettente. Imponendo due criteri di rottura, il raggiungimento della resistenza a trazione ed a compressione del calcestruzzo, inserendo le componenti di sollecitazione tramite le formule di Navier e Jourawsky, sono state definite due formule che mettono in relazione le tre azioni e che, implementate nel software Matlab, hanno permesso la costruzione di un dominio tridimensionale. In questo caso non è stato possibile confrontare i risultati, non avendo la ricerca bibliografica mostrato niente di paragonabile.
Lo studio si è poi concentrato sullo sviluppo di una procedura che tenta di analizzare il comportamento di una sezione sottoposta a sforzo normale, taglio e momento: è stato sviluppato un modello a fibre della sezione nel tentativo di condurre un calcolo non lineare, corrispondente ad una sequenza di analisi lineari.
La procedura è stata applicata a casi reali di crollo, confermando l’avvenimento dei collassi.
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Metelues, Francis Gabriel. "The Knee Response during Squats with Heels Up and Down." University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1388574269.
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Henry, Jason Matthew. "Theory and implementation of the naturally transitioning rate-to-force controller including force reflection using kinematically dissimilar master/slave devices." Ohio : Ohio University, 1999. http://www.ohiolink.edu/etd/view.cgi?ohiou1175879099.
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LIMA, LUCIANO RODRIGUES ORNELAS DE. "BEHAVIOUR OF STRUCTURAL STEEL ENDPLATE JOINTS SUBJECTED TO BENDING MOMENT AND AXIAL FORCE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4165@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOTradicionalmente, o projeto de pórticos em estruturas de aço assume que as ligações viga-coluna são rígidas ou flexíveis. As ligações rígidas, onde não ocorre nenhuma rotação entre os membros conectados, transferem não só momento fletor, mas também força cortante e força normal. Por outro lado, as ligações flexíveis são caracterizadas pela liberdade de rotação entre os membros conectados impedindo a transmissão de momento fletor. Desconsiderando- se estes fatos, sabe-se que a grande maioria das ligações não possuem este comportamento idealizado. De fato, a maioria das ligações transfere algum momento fletor com um nível de rotação associado. Estas ligações são chamadas semi-rígidas e seu dimensionamento deve ser executado de acordo com este comportamento estrutural real. Porém, algumas ligações viga-coluna estão sujeitas a uma combinação de momento fletor e esforço axial. O nível de esforço axial pode ser significativo, principalmente em ligações de pórticos metálicos com vigas inclinadas, em pórticos não-contraventados ou em pórticos com pavimentos incompletos. As normas atuais de dimensionamento de ligações estruturais em aço não consideram a presença de esforço axial (tração e/ou compressão) nas ligações. Uma limitação empírica de 5 por cento da resistência plástica da viga é a única condição imposta no Eurocode 3. O objetivo deste trabalho é descrever alguns resultados experimentais e numéricos para estender a filosofia do método das componentes para ligações com ações combinadas de momento fletor e esforço axial. Para se cumprir este objetivo, quinze ensaios foram realizados e um modelo mecânico é apresentado para ser usado na avaliação das propriedades da ligação: resistência à flexão, rigidez inicial e capacidade de rotação.
Traditionally, the steel portal frame design assumes that beam-to-column joints are rigid or pinned. Rigid joints, where no relative rotations occur between the connected members, transfer not only substantial bending moments, but also shear and axial forces. On the other extreme, pinned joints, are characterised by almost free rotation movement between the connected elements that prevents the transmission of bending moments. Despite these facts, it is largely recognised that the great majority of joints does not exhibit such idealised behaviour. In fact, many joints transfer some bending moments associated with rotations. These joints are called semi-rigid, and their design should be performed according to their real structural behaviour. However, some steel beam-to-column joints are often subjected to a combination of bending and axial forces. The level of axial forces in the joint may be significant, typical of pitched-roof portal frames, sway frames or frames with incomplete floors. Current standard for steel joints do not take into account the presence of axial forces (tension and/or compression) in the joints. A single empirical limitation of 5 percent of the beam s plastic axial capacity is the only enforced provision in Annex J of Eurocode 3. The objective of the present work is to describe some experimental and numerical results to extend the philosophy of the component method to deal with the combined action of bending and axial forces. To fulfil this objective a set of sixteen specimens were performed and a mechanical model was developed to be used in the evaluation of the joint properties: bending moment resistance, initial stiffness and rotation capacity.
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Ramdasi, Surabhi Suhas. "Enhancement of a Rolling Resistance Rig for Force and Moment Testing of Tires." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/71421.
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Tire testing has been one of the important aspects of the tire industry because it helps identify the tire behavior which further helps in improving the design of tires. It also helps automotive manufacturers choose the best tire for their automobiles. Indoor tire testing helps in relating the data better because of greater repeatability of the testing setup as compared to outdoor testing. This study focusses on modifying a rolling resistance machine to make it capable of force and moment and cleat testing along with the standard rolling resistance test. Additionally, the design of a mechanical loading mechanism (used to apply normal force on the tire) in place of the previous one using dead weights is also discussed.
This study also talks about the structural and vibrational finite element analysis of a tire testing machine. Since the machine was designed to conduct different tire tests, different structural requirements of the tire positioning mechanism pertaining to each test were taken into consideration, and the structure was analyzed for maximum forces and moments acting on the assembly. Cleat testing subjects the tire as well as the structure to an impulse force which calls for the vibrational analysis of the assembly to avoid the structure from resonating.
The design was modified to get it easily manufactured and assembled. These design changes and the aspects taken into consideration have also been discussed.Master of Science
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Gupta, Manoj Kumar. "Bulk-Flow analysis for force and moment coefficients of a shrouded centrifugal compressor impeller." Texas A&M University, 2005. http://hdl.handle.net/1969.1/2470.
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An analysis is developed for a compressible bulk-flow model of the leakage path
between a centrifugal compressor's impeller shroud and housing along the front and back
side of the impeller. This is an extension of analysis performed first by Childs (1989) for
a shrouded pump impeller and its housing considering an incompressible fluid, and then
later by Cao (1993) using a compressible bulk flow model for the shroud of a cryogenic
fluid pump. The bulk-flow model is used to develop a reaction force and moment model
for the shroud of a centrifugal compressor by solving the derived governing equations
and integrating the pressure and shear stress distribution. Validation is done by
comparing the results to published measured moment coefficients by Yoshida et al.
(1996). The comparison shows that the shroud casing clearance flow and the fluid force
moment can be simulated by the bulk flow model fairly well. An Iwatsubo-based
labyrinth seal code developed by Childs and Scharrer (1986) is used to calculate the
rotordynamic coefficients developed by the labyrinth seals in the compressor. Tangential
force and transverse moment components acting on the rotor are found to have a
destabilizing influence on the rotor for a range of precession frequencies. Rotordynamic
coefficients are derived for a single stage of a multistage centrifugal compressor, and a
comparison is made to stability predictions using Wachel's coefficient using the XLTRC
(rotordynamic FEA code). For the model employed, Wachel's model predicts a slightly
lower onset speed of instability. The results also show that leakage that flows radially
inwards on the back shroud has a greater destabilizing influence than leakage flow that is
radially outwards. Seal rub conditions are simulated by increasing the clearance and
simultaneously decreasing the tooth height, which increased the leakage and the swirl tothe eye seal inlet; and therefore reduced stability. Calculated results are provided for
different seal clearances and tooth height, for seal and shroud forces and moments.
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Tucker, John R. "The design, manufacture and verification of a high capacity force and moment measurement system /." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0010/MQ36189.pdf.
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Arcano, Joseph Timothy Jr. "The force and moment on a submerged axisymmetric body moving near a sinusoidal wall." Thesis, Hurlburt Field, Fla. : JSOU Press, 1985. http://hdl.handle.net/10945/21345.
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Background -- Mechanics of terrorist financing -- Organizations with Mandates to disrupt terrorist financing -- Legal considerations -- Recommendations and desired effects -- Conclusion. Appendix A. FTO locations and the original pan-Islamic Caliphate -- Appendix B. Alternative financing mechanisms -- Appendix C. U.S. organizations and efforts to disrupt terrorist financing -- Appendix D. International organizations and efforts to disrupt terrorist financing -- Appendix E. International resolutions and conventions -- Appendix F. U.S. laws, federal regulations, Federal Register notices, and miscellaneous sources of DOD authority -- Appendix G. Worldwide information and intelligence network (WIIN) -- Appendix H. Acronyms and terms
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Karol, Sohit. "Effect of kinetic degrees of freedom on multi-finger force and moment stabilizing synergies." College Park, Md.: University of Maryland, 2008. http://hdl.handle.net/1903/8606.
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Thesis (M.A.) -- University of Maryland, College Park, 2008.Thesis research directed by: Dept. of Kinesiology. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Stagg, Gregory A. "An Aerodynamic Model for Use in the High Angle of Attack Regime." Thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/35596.
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Harmonic oscillatory tests for a fighter aircraft using the
Dynamic Plunge--Pitch--Roll model mount at Virginia Tech Stability
Wind Tunnel are described. Corresponding data reduction methods are
developed on the basis of multirate digital signal processing. Since
the model is sting mounted, the frequencies associated with sting
vibration are included in balance readings thus a linear filter must
be used to extract out the aerodynamic responses. To achieve this, a
Finite Impulse Response (FIR) is designed using the Remez exchange
algorithm.
Based on the reduced data, a state--space model is developed to
describe the unsteady aerodynamic characteristics of the aircraft
during roll oscillations. For this model, we chose to separate the aircraft
into panels and model the local forces and moments. Included in this
technique is the introduction of a new state variable, a separation
state variable which characterizes the separation for each panel.
This new variable is governed by a first order differential equation.
Taylor series expansions in terms of the input variables were performed
to obtain the aerodynamic coefficients of the model. These
derivatives, a form of the stability derivative approach, are not
constant but rather quadratic functions of the new state variable.
Finally, the concept of the model was expanded to allow for the
addition of longitudinal motions. Thus, pitching moments will be
identified at the same time as rolling moments. The results show that
the goal of modeling coupled longitudinal and lateral--directional
characteristics at the same time using the same inputs is feasible.Master of Science
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Dickof, Carla. "Clt infill panels in steel moment resisting frames as a hybrid seismic force resisting system." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44209.
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This paper examines CLT-steel hybrid systems at three, six, and nine storey heights to increase seismic force resistance compared to a plain wood system. CLT panels are used as infill in a steel moment frame combining the ductility of a steel moment frame system with a stiffness and light weight of CLT panels. This system allows for the combination of high strength and ductility of steel with high stiffness and light weight of timber. This thesis examines the seismic response of this type of hybrid seismic force resisting system (SFRS) in regions with moderate to high seismic hazard indices. A detailed non-linear model of a 2D infilled frame system and compared to the behavior of a similar plain steel frame at each height.
Parametric analysis was performed determining the effect of the panels and the connection configuration, steel frame design, and panel configuration in a multi-bay system. Static pushover loading was applied alongside semi-static cyclic loading to allow a basis of comparison to future experimental tests. Dynamic analysis using ten ground motions linearly scaled to the uniform hazard spectra for Vancouver, Canada with a return period of 2% in 50 years as, 10% in 50 years, and 50% in 50 years to examine the effect of infill panels on the interstorey drift of the three, six, and nine storey. The ultimate and yield strength and drift capacity are determined and used to determine the overstrength and ductility factors as described in the National Building Code of Canada 2010.
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Martinez, Villalpando Ernesto Carlos. "Estimation of ground reaction force and zero moment point on a powered ankle-foot prosthesis." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37271.
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Thesis (S.M.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2006.Includes bibliographical references (leaves 89-97).
Commercially available ankle-foot prostheses are passive when in contact with the ground surface, and thus, their mechanical properties remain fixed across different terrains and walking speeds. The passive nature of these prostheses causes many problems for lower extremity amputees, such as a lack of adequate balance control during standing and walking. The ground reaction force (GRF) and the zero moment point (ZMP) are known to be basic parameters in bipedal balance control. This thesis focuses on the estimation of these parameters using two prostheses, a powered ankle-foot prototype and an instrumented, mechanically-passive prosthesis worn by a transtibial amputee. The main goal of this research is to determine the feasibility of estimating the GRF and ZMP primarily using sensory information from a force/torque transducer positioned proximal to the ankle joint. The location of this sensor is ideal because it allows the use of a compliant artificial foot to be in contact with the ground, in contrast to rigid foot structures employed by walking robots. Both, the active and passive, instrumented prostheses were monitored with a wearable computing system designed to serve as a portable control unit for the active prototype and as an ambulatory gait analysis tool.
(cont.) A set of experiments were conducted at MIT's gait laboratory whereby a below-knee amputee subject, using the prosthetic devices, was asked to perform single-leg standing tests and slow-walking trials. For each experiment, the GRF and ZMP were computed by combining the kinetic and kinematic information recorded from a force platform and a 3D motion capture system. These values were statistically compared to the GRF and ZMP estimated from the data collected by the embedded prosthetic sensory system and portable computing unit. The average RMS error and correlation factor were calculated for all experimental sessions. Using a static analysis procedure, the estimation of the vertical component of GRF had an averaged correlation coefficient higher than 0.96. The estimated ZMP location had a distance error of less than 1 cm, equal to 4% of the anterior-posterior foot length or 12% of the mediolateral foot width. These results suggest that it is possible to estimate the GRF between the ground and a compliant artificial prosthesis with a sensor positioned between the knee and the ankle joint.
(cont.) Moreover, this sensory information is sufficient to closely estimate the ZMP location during the single support phase of slow walking and while standing on one leg. This research contributes to the development of fully integrated artificial extremities that mimic the behavior of the human ankle-foot complex, especially to help improve the postural stability of lower extremity amputees.
by Ernesto Carlos Martinez Villalpando.
S.M.
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Ibrahim, Azmi. "Behaviour of unstiffened and bolt-stiffened RHS beams under combined bending moment and concentrated force." Thesis, University of Sussex, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.240405.
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Snell, Lloyd Dale. "Force and moment analysis of stacked counter rotating eccentric mass tree shaker energy-wheel system." [Ames, Iowa : Iowa State University], 2008.
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Davis, Matthew Harris. "A Bond Valence-Based Force Field: A Multi-Body Approach." BYU ScholarsArchive, 2013. https://scholarsarchive.byu.edu/etd/3796.
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The typical form for a molecular mechanics force field consists of a foundation of pair-wise terms to describe bonded and non-bonded atomic interactions, with multi-body correction terms to deal with the limitations of pair-wise terms. I present here the first attempts of a molecular mechanics model that is founded on multi-body terms, which are based on the Bond Valence Model (Brown, 2002) and recent developments in the Vectorial Bond Valence Model (Bickmore et al., 2013a; Harvey et al., 2006). I calibrated these models on pressure vs. energy curves for a set of SiO2 polymorphs. The average deviation for the best-fit iteration, with only six adjustable parameters was ±1.98 kcal/mol.
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Wearing, Christopher. "Evaluation of force distribution within a dual special moment-resisting and special concentric-brace frame system." Thesis, Kansas State University, 2017. http://hdl.handle.net/2097/35483.
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Master of ScienceDepartment of Architectural Engineering and Construction Science
Kimberly W. Kramer
Dual Lateral Force Resisting Systems are currently required by code to include a Moment Resisting Frame capable of resisting at least 25% of the lateral loads. This thesis evaluates the seismic performance of a specific type of dual system: a Special Moment Resisting Frame-Special Concentric Brace Frame System (SMRF-SCBF) under three different force distributions. The three distributions were 80% - 20%, 75% - 25%, and 70% - 30% with the lesser force being allotted to the Special Moment Resisting Frame (SMRF) portion of the system. In order to evaluate the system, a parametric study was performed. The parametric study consisted of three SMRF-SCBF systems designed with different seismic force distributions. The aim of this study was to determine accuracy of the three different seismic force distributions. The accuracy was measured by comparing individual system models’ data and combined system models’ data. The data used for comparison included joint deflections (both horizontal and vertical), induced moments at moment connections, brace axial loads, column shears, and column base reactions. Two-dimensional models using the structural software RISA 3D were used to assist in designing the independent Seismic Force Resisting Systems. The designs of the frames were not finely tuned (smallest member size for strength), but were designed for drift (horizontal deflection) requirements and constructability issues. Connection designs were outside the scope of the study, except for constructability considerations – the SMRF and the SCBF did not have a common column; the frames were a bay apart connected with a link beam. The results indicated that a seismic force distribution of 75% to the SCBF and 25% to the SMRF most accurately predicts that frame’s behavior. A force distribution of 80% to the SCBF and 20% to the SMRF resulted in moderately accurate results as well. A vast opportunity for further research into this area of study exists. Alterations to the design process, consideration of wind loads, or additional force distributions are all recommended changes for further research into this topic.
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Kaye, Tari Eileen Carleton University Dissertation Engineering Mechanical and Aerospace. "Techniques for aircraft force and moment model development using geometry and stability and control derivative estimates." Ottawa, 1994.
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Sherban, V. Yu. "Software components of the system for the kinematic and dynamic analysis of machines for sewing, textile and shoe industries." Thesis, Київський національний університет технологій та дизайну, 2017. https://er.knutd.edu.ua/handle/123456789/6655.
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Yoon, Hyunse Stern Frederick Longo Joseph. "Phase-averaged stereo-PIV flow field and force/moment/motion measurements for surface combatant in PMM maneuvers." [Iowa City, Iowa] : University of Iowa, 2009. http://ir.uiowa.edu/etd/453.
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Yoon, Hyunse. "Phase-averaged stereo-PIV flow field and force/moment/motion measurements for surface combatant in PMM maneuvers." Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/453.
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Towing-tank experiments are performed for a surface combatant as it undergoes static and dynamic planar motion mechanism maneuvers in calm water. The data includes global forces/moment/motions and phase-averaged local flow-fields, and uncertainty assessment. The geometry is DTMB model 5512, which is a 1/46.6 scale geosym of DTMB model 5415, with L = 3.048 m. The experiments are performed in a 3.048 × 3.048 × 100 m towing tank. The measurement system features a custom designed planar motion mechanism, a towed stereoscopic particle image velocimetry system, a Krypton contactless motion tracker, and a 6-component loadcell. The forces/moment and UA are conducted in collaboration with two international facilities (FORCE and INSEAN), including test matrix and overlapping tests using the same model geometry but with different scales. Quality of the data is assessed by monitoring the statistical convergence, including tests for randomness, stationarity, and normality. Uncertainty is assessed following the ASME Standards (1998 and 2005). Hydrodynamic derivatives are determined from the forces/moment data by using the Abkowitz (1966) mathematical model, with two different 'Multiple-Run (MR)' and 'Single-Run (SR)' methods. The results for reconstructions of the forces/moment indicate that usually the MR method is more accurate than the SR. Comparisons are made of the hydrodynamic derivatives across different facilities. The scale effect is small for sway derivatives, whereas considerable for yaw derivatives. Heave, pitch, and roll motions exhibit cross-coupling between the motions and forces and moment data, as expect based on ship motions theory. Hydrodynamic derivatives are compared between different mount conditions. Linear derivatives values are less sensitive to the mounting conditions, whereas the non-linear derivatives are considerably different. Phase-averaged flowfield results indicate maneuvering-induced vortices and their interactions with the turbulent boundary layer. The tests are sufficiently documented and detailed so as to be useful as benchmark EFD data for CFD validation.
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Cauthen, Rea Kimbrell III. "Design and Qualification of a Test Fixture to Experimentally Determine Global Tire Force Properties." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/46872.
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The advent of finite element methods has changed the tire industry's design process over the past three decades. Analyses, previously impractical using analytical methods and physically limited by experimental methods, can now be performed using computational methods. This decreases the cost and time associated with bringing a new design to the marketplace; however some physical testing is still required to validate the models.
The design, fabrication, installation, and operation of a tire, suspension, and chassis test fixture (TiSCTeF) is detailed as part of this study. This fixture will support the validation of effective, parametric finite element models currently under development, as well as the design and testing of suspension and chassis components for the Virginia Tech Formula SAE team. The fixture is designed to use the Formula SAE race car as the test platform. Initially, the fixture is capable of performing static load-deflection and free-rolling tire tests. Provision has been made in the design for incremental upgrades to support cornering tests and additional instrumentation.
An initial load-deflection test has proven that the fixture is capable of creating reproducible data sets. Specific recommendations are made concerning the improvement of data quality for future tests.
This study also presents a process for analyzing existing tire cornering data and eliminating anomalies to improve the effectiveness of normalization techniques found in the literature. The process is shown to collapse tire cornering data, which is partially ill- conditioned, onto master curves that consistently display the effect of inclination angle and tire inflation pressure on tire response.Master of Science
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Standifird, Tyler W. "Lower Extremity Joint Moments During the Active Peak Vertical Ground Reaction Force in Three Different Running Conditions." BYU ScholarsArchive, 2012. https://scholarsarchive.byu.edu/etd/2982.
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The purpose of this study was to compare joint moments during the active peak vertical ground reaction force (PVGRF) when running in three conditions. Twenty-five subjects, sixteen male and nine female, were measured using 3-dimensional motion analysis while running barefoot, in Vibram FiveFingers® (VF®) minimalist running shoes and in traditional running shoes at a 7-minute-mile pace (3.84 m/s). Joint moment differences were calculated and compared using a mixed model analysis of variance. Results showed the VF® was effective at mimicking both the kinetic and kinematic attributes of barefoot running. The only significant difference found when comparing barefoot and VF® running was in the ankle angle (p < .005). All other variables in the lower extremity were the same for the two conditions. Though the subjects in our study had no previous experience with VF® (or barefoot) running they were able to closely mimic barefoot running upon initial running trials. Joint moments at the ankle were higher for barefoot and VF® running (p < .001) when compared with shod running. This may potentially lead to a greater risk of injury at the ankle joint when running barefoot or in VF®. The hip joint moments were only different when comparing the barefoot condition to the shod condition (p=.002), with the barefoot condition higher than shod running. The knee joint moment was smaller during the VF® and barefoot conditions when compared with shod running (p < .001) and may lead to a decrease in injury rates at the knee. Though a reduction in moments of the lower extremity may lead to a decrease of injury at the corresponding joint, it is important to consider the adaptations that take place as a result of varying stresses. According to Wolff's law, bone and surrounding tissue will adapt to the loads it is placed under. Taking this into consideration, it is important to remember that lower moments may lead to weaker bones and surrounding tissues and without compensation for these reduced loads, injury rates may remain the same over time.
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Campbell, Brian Jude Weimar Wendi Hannah. "Wrist extension counter-moment force effects on muscle activity of the ECR with gripping implications for lateral epicondylagia /." Auburn, Ala., 2006. http://repo.lib.auburn.edu/Send%206-15-07/CAMPBELL_BRIAN_6.pdf.
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Lavoie, Mathieu. "La relation critique de T.W. Adorno à S.A. Kierkegaard : la force du sujet au moment de sa chute." Master's thesis, Université Laval, 2005. http://hdl.handle.net/20.500.11794/43698.
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Le double objectif de cette étude est d'examiner le rôle crucial joué par le concept de sujet dans les pensées d'Adorno et de Kierkegaard et de ressaisir les enjeux de la critique adornienne de la théorie kierkegaardienne du sujet. Pour ce faire, l'étude engage son investigation sur trois fronts. D'abord, elle s'attache à examiner la présentation kierkegaardienne de la théorie du sujet dans le Post-scriptum aux Miettes philosophiques. Ensuite, elle analyse sa critique immanente à l'intérieur de l' Habilitationsschrift d'Adorno: Kierkegaard. Construction de l'esthétique. Dans la conclusion, elle opère un retour dialectique sur les deux sections antérieures et fait voir que, si Kierkegaard et Adorno misent sur le sujet comme force de résistance face à l'oppression exercée par la totalité sociale, ils signalent l'inanité de tout volontarisme politique.
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Mills, Matthew. "A multipolar polarisable force field method from quantum chemical topology and machine learning." Thesis, University of Manchester, 2012. https://www.research.manchester.ac.uk/portal/en/theses/a-multipolar-polarisable-force-field-method-from-quantum-chemical-topology-and-machine-learning(3fb1e55c-0d4c-4d11-932b-71706bdbeb8b).html.
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Force field methods are used to investigate the properties of a wide variety of chemical systems on a routine basis. The expression for the electrostatic energy typically does not take into account the anisotropic nature of the atomic electron distribution or the dependence of that distribution on the system geometry. This has been suggested as a cause of the failure of force field methods to reliably predict the behaviour of chemical systems. A method for incorporation of anisotropy and polarisation is described in this work. Anisotropy is modelled by the inclusion of multipole moments centred at atoms whose values are determined by application of the methods of Quantum Chemical Topology. Polarisation, the dependence of the electron distribution on system geometry, is modelled by training machine learning models to predict atomic multipole moments from knowledge of the nuclear positions of a system. The resulting electrostatic method can be implemented for any chemical system. An application to progressively more complex systems is reported, including small organic molecules and larger molecules of biological importance. The accuracy of the method is rigorously assessed by comparison of its predictions to exact interaction energy values. A procedure for generating transferable atomic multipole moment models is defined and tested. The electrostatic method can be combined with the empirical expressions used in force field calculations to describe total system energies by fitting parameters against ab initio conformational energies. Derivatives of the energy are given and the resulting multipolar polarisable force field can be used to perform geometry optimisation calculations. Future applications to conformational searching and problems requiring dynamic descriptions of a system are feasible.
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Buell, Grant. "Comparison of structural steel lateral force resisting systems for a theoretical hospital grid system." Manhattan, Kan. : Kansas State University, 2009. http://hdl.handle.net/2097/2321.
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Noorkoiv, Marika. "Neuromuscular adaptations of joint angle-specific force change after isometric training." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2013. https://ro.ecu.edu.au/theses/531.
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Increases in force production in response to isometric training typically occur at or around the joint angles adopted during the training, but the mechanisms underpinning this have not yet been fully elucidated. This PhD thesis project investigated the mechanisms underpinning joint angle-specific strength changes after isometric training, focussing on muscle region-specific cross-sectional area (CSA), muscle fascicle length (Lf) and muscle activation adaptations. For this, the validity and reliability of a two-dimensional extended-field-of-view ultrasonography (EFOV) method for measuring muscle CSA (Study 1) and Lf (Study 2) were examined. Small standard errors of measurement (SEM) and high intra-class correlations (ICCs) were found for CSA measurements (0.6-1.2% and 0.95-0.99, respectively) at proximal and mid-thigh (30, 40 and 50% of the distance from the superior border of the patella to the medial aspect of anterior superior iliac spine) but not distal sections and CSA measurements were very similar to those obtained using computed tomography scanning. Small SEMs and high ICCs were also obtained for Lf measurements (0.8% and 0.95, respectively), and they were accurate when compared to directly-measured swine muscle fascicles. Nonetheless, because of the time required for EFOV CSA scanning and its unreliability for the distal quadriceps (despite a high ICC, the 95% CI of ICC at 20% section = -0.04-0.99), MRI was used for CSA measurement in the subsequent study.
The third study aimed to examine joint angle-specific neuromuscular adaptations in response to isometric knee extension training at short (SL; !knee = 38.1 ± 3.7°) versus long (LL; !knee = 87.5 ± 6.0°) muscle lengths. Sixteen men trained three times a week for six weeks at a knee angle at which peak muscle force (i.e. quadriceps torque/moment arm) was 80% of the peak force obtained at the optimum joint angle. Clear joint angle specificity was seen in SL (force increased 13.4 ± 2.4% at 40°), which was associated with an increase in VL EMG around the training (40°; 26.4 ± 15.5%) and adjacent (50°; 22.5 ± 14.9%) angles, without a shift in the electrically evoked force-angle relationship or changes in muscle size. In contrast, increases in force in LL occurred at angles further from the training angle and varied between subjects. Also, muscle volume and CSA increased significantly and the changes in CSA of specific muscle regions were correlated with the changes in peak force produced at both 30° and at 100°. This occurred with small changes in vastus lateralis (VL) and rectus femoris (RF) muscle EMG activity and no detectable change in coactivation, thus selective regional muscle hypertrophy was most associated with the direction of shift in the force-length relationship. A small (5.4 ± 1.4%) and similar increase in Lf was found in both groups, which was not associated with angle-specific force changes. The effect of isometric training on the concentric torque-velocity relationship was examined in Study 4 to determine whether the isometric training influenced dynamic force production. Isokinetic torque at seven velocities (30, 60, 90, 120, 180, 240 and 300°"s-1) was assessed at weeks 0, 3 and 6. Torque increased only in LL, and only at slow angular velocities (30 - 120°"s-1). The change in torque correlated well with changes in VL, VM and RF CSA, although there was little relationship with Lf. There was no change in angle of peak isokinetic torque.
These results reveal a different mechanism of joint angle–specific adaptation between training at short versus long muscle lengths; neural adaptations underpinned changes after training at short quadriceps lengths but muscular (hypertrophic) changes predominated after training at long lengths. Importantly, clear angle specificity was only observed after training at the short length, although muscle mass acquisition and improvements in dynamic muscle force production were elicited only after training at longer lengths. Thus, although specificity is reduced, greater functional benefit appears to be derived after training at longer lengths. Further research is required to determine why some individuals improved force production at shorter muscle lengths after training only at longer muscle lengths and whether such ‘nonspecificity’ can be predicted before training.
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Trahan, Jacques. "Modélisation du moment de force à partir de l'activité électromyographique, de l'angle et de la vitesse angulaire du segment." Thèse, Université du Québec à Trois-Rivières, 1991. http://depot-e.uqtr.ca/5480/1/000587549.pdf.
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Snow, Scott Karl. "Numerical Analysis of Passive Force on Skewed BridgeAbutments with Reinforced Concrete Wingwalls." BYU ScholarsArchive, 2008. https://scholarsarchive.byu.edu/etd/7399.
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Numerical Analysis of Passive Force on Skewed BridgeAbutments with Reinforced Concrete WingwallsScott Karl SnowDepartment of Civil and Environmental Engineering, BYU Master of Science Historically bridges with skewed abutments have proven more likely to fail during earthquake loadings (Toro et al, 2013) when compared to non-skewed bridges (Apirakvorapinit et al. 2012; Elnashai et al. 2010). Previous studies including small-scale laboratory tests by Jessee (2012), large-scale field tests by Smith (2014), and numerical modeling by Shamsabadi et al. (2006) have shown that 45° skewed bridge abutments experience a reduction in peak passive force by about 65%. With numerous skewed bridges in the United States, this study has great importance to the nation's infrastructure.The finite element models produced in this study model the large-scale field-testing performed by Smith (2014), which was performed to study the significant reduction in peak passive resistance for abutments with longitudinal reinforced concrete wingwalls. The finite element models largely confirm the findings of Smith (2014). Two models were created and designed to match the large-scale field tests and were used to calibrate the soil parameters for this study. Two additional models were then created by increasing the abutment widths from 11 feet to 38 feet to simulate a two-lane bridge. The 45° skewed 11-foot abutment experienced a 38% reduction in peak passive resistance compared to the non-skewed abutment. In contrast, the 45° skewed 38-foot abutment experienced a 65% reduction in peak passive resistance compared to the non-skewed abutment. When the wingwalls are extended 10 feet into the backfill the reduction decreased to 59% due to the change in effective skew angle.The finite element models generally confirmed the findings of Smith (2014). The results of the 11- and 38-foot abutment finite element models confirmed that the wingwall on the obtuse side of the 45° skewed abutments experienced approximately 4 to 5 times the amount of horizontal soil pressure and 5 times the amount of bending moment compared to the non-skewed abutment. Increases in the pressures and bending moments are likely caused by soil confined between the obtuse side of the abutment and the wingwall.A comparison of the 11- and 38-foot 45° skewed abutment models showed a decrease in the influence of the wingwalls as the abutment widened. The wingwall on the acute side of the 38-foot abutment developed approximately 50% of the horizontal soil pressure compared to the 11-foot abutment. The heave distribution of the 11-foot abutment showed approximately 1- to 2-inches of vertical displacement over a majority of the abutment backwall versus more than half of the 38-foot abutment producing ½ an inch or less.
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Waugh, Charlotte. "The effects of age- and training-related changes in tendon stiffness on muscular force production and neuro-motor control during childhood." Thesis, Brunel University, 2011. http://bura.brunel.ac.uk/handle/2438/6596.
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The research described in this thesis examined age- and strength training-related changes in Achilles tendon stiffness and plantarflexor force production in prepubertal children. The measurement of both Achilles tendon stiffness and muscular force production requires in vivo moment arm lengths to be known. Currently, this is possible only by using expensive and time-consuming medical imaging methodologies. Therefore, the predictability of the Achilles tendon moment arm from surface anthropometric measurements was assessed in the first experimental study (Chapter 3). The results demonstrated that a combination of foot length and the distance between the calcaneal tuberosity and 1st metatarsal head could explain 49% of the variability in Achilles tendon moment arm length in 5 – 12 year-old children. This was considered to be unacceptable for further use, thus an ultrasound-based method was decided upon for obtaining moment arm length in subsequent experimental studies. In the second and third experimental studies (Chapters 4 and 5), age-related changes in tendon mechanical and structural properties were documented and their relationship with changes in force production ability were examined in prepubertal children (5 – 12 years) and adult men and women. In Chapter 4, Achilles tendon stiffness was shown to increase with age through to adulthood, and that changes in tendon stiffness were strongly and independently associated with body mass (R2 = 0.58) and peak force production capacity (R2 = 0.51),which may provide the tendon with an increasing mechanical stimulus for growth and microadaptation. These increases in tendon stiffness were associated with a greater increase in tendon CSA (~105%) than that found for tendon length (~60%), in addition to an increase in Young’s modulus (~139%), suggesting that gross increases in tendon size as well as changes in its microstructure underpinned the increase in stiffness. In Chapter 5, the relationships between Achilles tendon stiffness and both electro-mechanical delay (EMD) and rate of force development (RFD) were determined during maximal isometric plantarflexion contractions. Moderate correlations were found between tendon stiffness and both EMD (r = -0.66) and RFD (r = 0.58). RFD was significantly better predicted when muscle activation (estimated as the rate of EMG rise) was included in a regression model. These data clearly show that increases in tendon stiffness with age through to adulthood are associated with decreases in EMD and increases in RFD, and that the rate of muscle activation has an additional influence on RFD during growth. Given that 1) Achilles tendon stiffness was lower in children than adults, 2) this lower stiffness was associated with a longer EMD and slower RFD, and 3) that strength training in adults had previously been shown to increase tendon stiffness and RFD, the adaptability of the developing Achilles tendon to a resistance training programme, and consequence of the potential changes on force production capacity were examined in the final experimental study (Chapter 6). Significant increases in Achilles tendon stiffness and Young’s modulus were found after 10 weeks of twice-weekly plantarflexor strength training in 8-9 year-old boys and girls, which demonstrates that the larger muscle force production provided a sufficient stimulus for tendon microadaptation. The training also resulted in a decrease in EMD, which was moderately correlated with the change in tendon stiffness (r = 55), but no change in RFD. Thus, the increasing tendon stiffness with training was associated with a decreasing EMD, but had no detectable effect on RFD. This would likely have a significant effect on the performance of tasks requiring rapid muscle force production. Together, the results of the present series of investigations demonstrate that the tendon loading experienced from both normal ageing and overloading (strength training) can increase tendon stiffness in children, and that these changes have a detectable effect on rapid force production.
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Simoneau, Emilie. "Effets du vieillissement et de l'entrainement en force sur la production de moment en flexion plantaire et en dorsi-flexion." Dijon, 2006. http://www.theses.fr/2006DIJOS041.
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Ce travail de thèse vise à examiner, suite au vieillissement, mais aussi au renforcement musculaire, les adaptations sous-jacentes pouvant affecter les muscles agonistes et antagonistes à l’articulation de la cheville. Les principaux résultats montrent que i) le déclin du moment maximal dû à l’âge semble plus précoce en flexion plantaire (FP) qu’en dorsi-flexion (DF) ; ii) l’allure des relations moment maximal-angle semble être principalement expliquée par des paramètres nerveux en DF et par des paramètres musculaires en FP ; iii) lors d’évaluations, des mesures à un seul angle de la cheville sont suffisantes ; iv) un programme d’entraînement en force de longue durée des fléchisseurs plantaires chez les personnes âgées est très efficace pour augmenter le moment maximal en FP, avec des adaptations musculaires tardives ; v) la performance maximale isométrique des muscles agonistes en DF et en FP apparaît, in fine, pareillement affectée par le vieillissementThe primary goal of this manuscript is to investigate the effects of aging and also of strength-training on agonist and antagonist muscles responsible for the torque generation at the ankle joint, in plantar-flexion (PF) and dorsi-flexion (DF). The main findings show that i) the age-related decline in the maximal torque seems to be of an earlier onset in PF than in DF; ii) the maximal torque-angle relationship appears to be especially explained by neural parameters in DF and by muscular parameters in PF; iii) for any assessment, measurements at one ankle joint angle are enough; iv) a long-term strength-training program of the PF muscles in old age is very effective in increasing strength in PF, with late muscular adaptations; v) the isometric maximal performance of the agonist muscles in DF and PF is, in fine, similarly affected with aging
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Toledo, Joelly Manhic de. "Determinação do momento proximal resultante e da força proximal resultante no ombro em exercícios de reabilitação com três diferentes situações de carga." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2008. http://hdl.handle.net/10183/15290.
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Este estudo teve como objetivo determinar os picos de momento proximal resultante (MPR) e força proximal resultante (FPR) no ombro em alguns exercícios de reabilitação (elevação no plano escapular, flexão e abdução) em três diferentes situações de carga: sem carga (SC), com peso livre (HA) e com resistência elástica (RE). Participaram do estudo 21 indivíduos do sexo masculino, destros e sem histórico de lesão no ombro direito. Para análise cinemática foram utilizadas cinco câmeras digitais conectadas a cinco microcomputadores e, para análise cinética na situação de carga com RE, foi utilizada uma célula de carga. Cada indivíduo realizou cinco repetições de cada movimento com as três situações de carga em uma ordem randomizada, totalizando a participação em nove situações para análise. Um modelo matemático tridimensional foi utilizado para o cálculo do MPR e da FPR, a partir dos eixos: póstero-anterior (x), caudal-cranial (y) e médio-lateral (z). Na análise estatística dos dados a normalidade dos dados foi confirmada por meio do teste de Shapiro-Wilk. Os dados de pico de MPR e FPR e ângulo de ocorrência desses picos nas três situações de carga e nos três diferentes movimentos foram comparados entre si em relação às suas magnitudes por meio do teste ANOVA two-way com um post hoc de Bonferroni (nível de significância de p< 0,05). Os resultados mostram que no eixo x e no z houve diferença estatisticamente significativa para todas as variáveis analisadas nos dois fatores. Já no eixo y o ângulo de ocorrência dos picos da FPR no fator movimento não apresentou diferença estatística. Houve interação dos fatores para o ângulo de ocorrência dos picos do MPR no eixo x e para o pico do MPR no eixo y. Os exercícios de reabilitação que apresentaram maior pico da FPR no eixo x e no eixo y foram o de elevação e flexão, e no eixo z o de abdução e os que apresentaram maior pico do MPR nos eixos x e y foram o de abdução, e no eixo z o de flexão e elevação. As situações de carga que apresentaram maior pico da FPR no eixo x foram a HA e a RE, e nos eixos y e z foi a HA. A situação de carga que apresentou maior pico do MPR nos três eixos foi a HA.The objective of this study was to determine the proximal net moment (PNM) and proximal net force (PNF) peaks of the shoulder in some shoulder rehabilitation exercises (elevation, flexion and abduction) with three different load situations: without load (WL), with free load (FL) and with elastic resistance (ER). Twenty-one male subjects, right-handed and without right shoulder injury history participated in the study. For kinematics analysis, five digital cameras connected to five computers were used and, for kinetic analysis for the ER load situation, a strain gauge was used. Each subject carried out five repetitions of all movements with the three load situations in a randomized order and, therefore, participated of nine situations of analysis. A three-dimensional mathematic model was used to calculate the PNM and PNF and the axes used are: posterior-anterior (x), inferior-superior (y) and medio-lateral (z). In the data statistic analysis, data normality was confirmed by Shapiro-Wilk test. The data of PNM peak, PNF peak and angle which these peaks occur in the three different situation loads and in the three different movements were compared using a two-way repeated measures analysis of variance (ANOVA) with Bonferroni post hoc test (significance level of 0,05). The results show that in the x and z axes there is significant statistical difference for all variables analised in the two factors. However, in the y axis the angle where the peak PNF occur does not reveals statiscal difference in the movement factor. With regard to factors interaction, there are just two significants for PNF peak angle in the x axis and for PNF peak in the y axis. In conclusion, the exercises that have the greater PNF peak in the x and y axes were elevation and flexion, and in the z axis was abduction. The exercises that have the greater PNM peak in the x and y axes was abduction and in the z axis were flexion and elevation. The load situations that presented the greater PNF peak in the x axis were FL and ER and in the y and z axes was FL. The situation load that has the greater PNM peak in all axes was FL.
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Tort, Marine. "Dynamique et modélisation des atmosphères profondes." Palaiseau, Ecole polytechnique, 2015. https://pastel.archives-ouvertes.fr/tel-01137840.
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Les mouvements de l'atmosphère terrestre sont assez bien décrits dans le cadre de l'approximation d'atmosphère mince, qui néglige l'épaisseur de l'atmosphère devant le rayon de la Terre. Titan, le plus grand satellite de Saturne, possède une atmosphère épaisse, le rapport de l'épaisseur par le rayon planétaire atteignant près de 25%. Pour modéliser et comprendre sa circulation générale, il est ainsi préférable voire indispensable de ne pas faire l'approximation de couche mince. Cette thèse résout des problèmes liés à la modélisation de ce type d'atmosphères dites profondes, et aborde des questions visant à la compréhension de leur dynamique. L'approximation de couche mince et l'approximation traditionnelle qui néglige la partie de la force de Coriolis associée à la composante horizontale du vecteur rotation de la planète (appelée également partie non-traditionnelle) semblent indissociables pour satisfaire la conservation du moment cinétique absolu. Nous montrons pourtant qu'il est possible de retenir les termes non-traditionnels sous l'approximation de couche mince tout en satisfaisant les lois de conservation, et ce dans les équations d'Euler compressibles et dans celles de Saint-Venant sur la sphère. Pour certains cas d'écoulements terrestres, étant donné le petit rapport d'aspect, ce nouveau modèle NT est suffisamment précis. Dans ce cas, nous réalisons plusieurs études idéalisées de stabilité de jet zonaux et de turbulence en déclin, dans le cadre de modèles de Saint-Venant et de Boussinesq en prenant en compte la force de Coriolis complète. Nous mettons en évidence les paramètres pour lesquels les effets non-traditionnels sont significatifs et discutons des effets dans des cas réalistes. Pour modéliser la circulation atmosphérique de Titan, nous intégrons les équations quasi-hydrostatiques en levant l'approximation de couche mince dans le coeur dynamique du modèle de circulation générale LMD-Z (Titan). Après avoir identifié la structure Hamiltonienne des équations, nous imitons ce formalisme au niveau discret de manière à conserver l'énergie totale dans le modèle. Divers cas tests sont mis en place afin de valider la stabilité et la précision du nouveau coeur dynamique. Finalement, le nouveau coeur est appliqué à l'atmosphère de Titan. Dans un premier temps une simulation idéalisée est réalisée en partant de vents au repos et en utilisant un rappel newtonien vers une température d'équilibre issue d'un profil vertical mesuré par la sonde Huygens. Des simulations plus réalistes sont mises en place en couplant le c{\oe}ur dynamique profond avec les paramétrisations physiques de LMD-Z (Titan)Large-scale atmospheric and oceanic motions are fairly well described under the so-called shallow-atmosphere approximation, which neglects the thickness of the atmosphere comparing to the planetary radius. Titan is the biggest moon of Saturn and has a thick atmosphere with an aspect ratio reaching almost 25%. It is then preferable not to make the shallow-atmosphere approximation to model its atmospheric general circulation. This thesis solves problems in modeling of such deep-atmospheres and addresses some issues for understanding their dynamics. The shallow-atmosphere and traditional approximation neglecting the part of the Coriolis force due to the horizontal component of the planetary rotation rate vector (also called as non-traditional part) seem to be inseparable to satisfy the conservation of absolute angular momentum. However, we show that it is possible to retain non-traditional terms under the shallow-atmosphere approximation while satisfying all conservation laws, in the compressible Euler equations as well as in the shallow-water equations on the rotating sphere. In most cases, given the small aspect ratio, this new non-traditional model is accurate. In this case, several idealized zonal jet stability and free evolving turbulence studies have been conducted using shallow-water and Boussinesq models taking into account the complete Coriolis force. We highlight the parameters for which the non-traditional effects are significant and discuss the dynamical effects in realistic cases. To model general circulation of Titan's atmosphere, we integrate the quasi-hydrostatic equations in the dynamical core of the LMD-Z (Titan) atmospheric general circulation model. After identifying the Hamiltonian structure of the equations, we imitate the formulation at discrete level to conserve total energy. Various test cases are performed in order to validate the stability and the accuracy of the new dynamical core. The latter is applied to Titan's atmosphere. Firstly, an idealized simulation is performed starting from an atmosphere at rest and using a Newtonian relaxation. Then more realistic simulations are implemented using parameterizations of LMD-Z (Titan)
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Miller, Stuart Charles. "Mechanical factors affecting the estimation of tibialis anterior force using an EMG-driven modelling approach." Thesis, Brunel University, 2014. http://bura.brunel.ac.uk/handle/2438/8763.
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The tibialis anterior (TA) muscle plays a vital role in human movement such as walking and running. Overuse of TA during these movements leads to an increased susceptibility of injuries e.g. chronic exertional compartment syndrome. TA activation has been shown to be affected by increases in exercise, age, and the external environment (i.e. incline and footwear). Because activation parameters of TA change with condition, it leads to the interpretation that force changes occur too. However,activation is only an approximate indicator of force output of a muscle. Therefore, the overall aim of this thesis was to investigate the parameters affecting accurate measure of TA force, leading to development of a subject-specific EMG-driven model, which takes into consideration specific methodological issues. The first study investigated the reasons why the tendon excursion and geometric method differ so vastly in terms of estimation of TA moment arm. Tendon length changes during the tendon excursion method, and location of the TA line of action and irregularities between talus and foot rotations during the geometric method, were found to affect the accuracy of TA moment arm measurement. A novel, more valid, method was proposed. The second study investigated the errors associated with methods used to account for plantar flexor antagonist co-contraction. A new approach was presented and shown to be, at worse, equivalent to current methods, but allows for accounting throughout the complete range of motion. The final study utilised the outputs from studies one and two to directly measure TA force in vivo. This was used to develop, and validate, an EMG-driven TA force model. Less error was found in the accuracy of estimating TA force when the contractile component length changes were modelled using the ankle, as opposed to the muscle. Overall, these findings increase our understanding of not only the mechanics associated with TA and the ankle, but also improves our ability to accurately monitor these.
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Marié, Louis. "Transport de moment cinétique et de champ magnétique par un écoulement tourbillonnaire turbulent : influence de la rotation." Phd thesis, Université Paris-Diderot - Paris VII, 2003. http://tel.archives-ouvertes.fr/tel-00007755.
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L'écoulement de von Karman est l'écoulement produit par la rotation de deux disques coaxiaux placés en vis-à-vis. Dans la première partie de cette thèse, nous présentons un certain nombre de résultats expérimentaux visant à la caractérisation des fluctuations à grande échelle d'un écoulement d'allongement sensiblement unitaire. Dans certaines circonstances, nous mettons notamment à jour une "bifurcation globale" ainsi qu'un comportement "intermittent" de la structure de l'écoulement. Nous présentons par ailleurs une relation qui relie les statistiques des fluctuations de l'écoulement aux valeurs des couples fournis par les moteurs. Enfin, nous ébauchons l'étude de l'influence de la force de Coriolis sur l'écoulement. La deuxième partie de cette thèse présente des résultats numériques et expérimentaux portant sur l'étude des caractéristiques magnéto-hydrodynamiques de l'écoulement, et notamment sur sa capacité à produire un champ magnétique par "effet dynamo". Les résultats expérimentaux ont été obtenus à haut nombre de Reynolds magnétique dans le montage "VKS", qui utilise du sodium liquide.
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Kašparů, Jakub. "Statické řešení betonového komínu." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2013. http://www.nusl.cz/ntk/nusl-226418.
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The goal of this Master´s thesis is a review of a reinforced concrete chimney´s stack and a foundation design based on a combination of M+N load. Two bar models (by ČSN and EN) and one shall model were created to analyze internal forces. The fine element software SCIA ENGINEERING was used to create the models. The loads taken into consideration - for analysis include self weight, lining, temperature, wind, and Karman vortex. The stack was horizontally divided by several cuts which were investigated. The stack and foundation were designed by an algorithm created in the program MS EXCEL. The piles were designed in the program GEO 5. Drawings include - drawings of shapes and drawings of the reinforcement of specifics part of chimney.
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Tamborindeguy, Aline Cavalheiro. "Avaliação da força e do momento tibiofemoral durante a pedalada : uma orientação para a reabilitação." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2009. http://hdl.handle.net/10183/17609.
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TAMBORINDEGUY, A. C. Avaliação da força e do momento tibiofemoral durante a pedalada: uma orientação para a reabilitação. Dissertação de Mestrado. Programa de pós-graduação em ciências do movimento humano. Escola de Educação Física. Universidade Federal do Rio Grande do Sul. Durante o processo de reabilitação de lesões na articulação do joelho o ciclo ergômetro tem sido amplamente utilizado. No entanto, existem poucos estudos que orientem a sua utilização de forma a evitar sobrecargas às estruturas lesionadas. O presente estudo tem como objetivo comparar o comportamento das componentes de compressão e de cisalhamento anterior e posterior da força intersegmentar e do momento resultante tibiofemoral durante a pedalada no ciclo ergômetro em situações usuais da reabilitação de lesões do joelho. Participaram deste estudo nove sujeitos saudáveis do sexo masculino. O protocolo constou da avaliação de três diferentes alturas do selim (altura do trocânter, 3 cm para baixo e 3 cm para cima desta), duas cadências (40 e 70 rpm) e três cargas de trabalho (0, 5 e 10 N) relacionadas à realidade da reabilitação. Um pedal instrumentado e um sistema de cinemetria foram utilizados para o cálculo do modelo biomecânico bidimensional. Foram analisadas as médias do pico de compressão da força intersegmentar, dos picos do valor máximo e mínimo de cisalhamento da força intersegmentar e o pico dos momentos flexor e extensor durante oito ciclos de pedalada. Os resultados obtidos demonstram que o aumento da carga de trabalho causa um aumento na média do pico de compressão e do pico máximo de cisalhamento da força intersegmentar. As médias do pico de compressão foram de -44,94 (±3,12) N para 0 N, -53,21 (±4,56) N para 5 N e -76,50 (±5,69) N para 10 N. As médias do pico máximo de cisalhamento foram de 61,32 (±5,60) N para O N, 71,21 (±7,73) N para 5 N e 93,89 (±9,10) N para 10 N. O aumento das cargas de trabalho também causou um aumento do pico do momento flexor resultante que teve valores médios de 12,77 (±1,68) Nm para 0 N, 16,90 (±2,49) Nm para 5 N e 25,40 (±3,25) Nm para 10 N. O pico do momento extensor aumentou com a diminuição da altura do selim. As médias do pico do momento extensor nas posições do selim na altura do trocânter, 3 cm abaixo e 3 cm acima foram de, -10,15 (±0,58) Nm, -11,09 (±0,55) Nm e -9,68 (±0,58) Nm, respectivamente. O pico do momento extensor aumentou com o aumento da cadência de pedalada e com o incremento da carga de trabalho de 5 para 10 N. As médias do pico do momento extensor foram de -10,12 (±0,57) Nm para 40 rpm, de - 10,49 (±0,56) Nm para 70 rpm, -10,19 (±0,57) Nm para 5 N e de -10,53 (±0,60) Nm para 10 N. Portanto, pedalar com uma carga de 0 N, com o selim posicionado 3 cm acima da altura do trocânter e na cadência de 40 rpm resulta em menor sobrecarga articular e muscular.TAMBORINDEGUY, A. C. Assessment of force and moment during cycling: an orientation to rehabilitation. Master thesis. Graduation Program in Human Movement Sciences. School of Physical Education. Federal University of Rio Grande do Sul. During knee injuries rehabilitation process the cycle ergometer has been largely used. However, there are few studies orienting their use avoiding overload damaged structures. The aim of the present study was to compare the effects of compression and shear force components and resultant joint moment in ergometer cycling at different saddle height, cadence and workload during rehabilitation seasons. Nine healthy male volunteers participated in this study. Protocol consisted of evaluation of three differents saddle heights (trochanter height, 3 cm downward and 3 cm upward from trochanter height), two cadences (40 and 70 rpm) and three workloads (0, 5 and 10 N). An instrumented pedal and a motion system were used to calculate the twodimensional biomechanical model. Mean peak compressive intersegmental force, maximum and minimum mean peak shear force, and mean peak extensor and flexor moment during eight pedaling cycles were analyzed. Results demonstrated that changes in workload interfere in mean peak compressive force as well in maximum mean peak shear intersegmentar force. Mean peak compressive were -44.94 (±3.12) N for 0 N, -53.21 (±4.56) N for 5 N and -76.50 (±5.69) N for 10 N. Maximum mean peak shear were 61.32 (±5.60) N for O N, 71.21 (±7.73) N for 5 N and 93.89 (±9.10) N for 10 N. Mean peak flexor moment increased as workload increase (12.77 (±1.68) Nm for 0 N, 16.90 (±2.49) Nm for 5 N and 25.40 (±3.25) Nm for 10 N). Mean peak extensor moment increased at saddle positioned 3 cm downward. Results were - 10.15 (±0.58) Nm, -11.09 (±0.55) Nm, and -9.68 (±0.58) Nm, for trochanteric height, 3 cm downward, and 3 cm upward, respectively. Mean peak extensor moment increased as cadence and workload increased (from -10.12 (±0.57) Nm at 40 rpm to - 10.49 (±0.56) Nm at 70 rpm; from -10.19 (±0.57) Nm at 5 N to -10.53 (±0.60) Nm at 10 N, respectively). Therefore, pedaling at 0 N with saddle positioned 3 cm upward from trochanter height at 40 rpm results in lower joint and muscle overload.
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Grøtner, Katrine, and Huy Hoang Pham. "Kinetik ved løb med dagligdagsprotese og løbespecifikprotese hos transtibial amputerede: Et cross-sectional studie." Thesis, Hälsohögskolan, Jönköping University, HHJ, Avd. för rehabilitering, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:hj:diva-49495.
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Formål: Formålet med studiet er at undersøge hvordan løb med en dagligdagsprotese og en løbespecifikprotese påvirker kinetik i nedre ekstremiteter hos mennesker med en transtibial-amputation. Metode: Kinetisk data blev indsamlet ved løbetests, med begge proteser, med et motion capture system og kraftplader i et klinisk ganganalyse lab i Göteborg, Sverige. Deltagere(n=2) udførte løbetests i selvvalgt hastighed, iført refleksive markører. Vertikal GRF, fod progressions vinkel, adducerende/abducerende hofte- og knæmoment udvalgt til videre databehandling. Resultat: Forskelle i hofte- og knæ adduktions moment og fod progressions vinkel blev observeret mellem de to protesetyper. Momenterne var mindre, når deltagerne løb med den løbespecifikke protese. Forskelle på den amputerede side og den kontralaterale side noteredes ved alle parametre uanset protesetype. Den kontralaterale side havde forøgede værdier sammenlignet med den amputerede side. Konklusion: Grundet forsøgets størrelse kan vi ikke konkludere, at individer med unilateral amputation i nedre ekstremitet absorberer belastning bedre, når de løber med en løbespecifikprotese fremfor en dagligdagsprotese.Aim: The aim of this study was to investigate how running with a daily-use prosthesis and a running specific prosthesis affects kinetics in the lower extremities when it comes to people with a transtibial amputation. Method: Kinetic data was collected through running tests, using both type of prosthesis, with a motion capture system and force plates in a clinical gait lab in Gothenburg, Sweden. Participants (n=2) executed the running tests in a self-selected speed, while wearing reflective markers. Vertical ground reaction force, foot progression angle, hip- and knee moment were selected for data processing. Results: Differences in hip- and knee adduction moment and foot progression angle were observed between the two types of prostheses. Moments were smaller when participants ran with running-specific prosthesis. Dissimilarity for the amputated side and the contralateral side were noted for all parameters regardless of type of prosthesis. The contralateral side had increased values compared to the amputated side. Conclusion: Because of the sample size we cannot conclude that individuals with a unilateral lower body amputation absorb load more efficiently when running with a running-specific prosthesis rather than a daily-use prosthesis.
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Jovanovic, Dejan, and Ruslan Khalilov. "Transverse force absorption in column base mounts for steel columns : Screw joints in column bases." Thesis, KTH, Byggteknik och design, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-302520.
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It is common to use different construction materials in combination such as concrete, steel, wood and glass in order to optimize buildings. The purpose of this is to reduce weight and increase load capacity, but it also facilitates assembly and reduces construction time. Steel column bases anchored in concrete foundations are an example of a combination of interaction nodes between steel and concrete elements. This report studies the friction between the lower edge of the base plate and the grout, which is a function of the normal force of the column. The friction that occurs between the square washer and the foot plate has also been examined as a result of the tightening moment. The work has placed great focus on discussing the advantages and disadvantages of the different methods for transverse force absorption in column bases. Delimitations have been made, the attachment of the column to the base plate has not been taken into account in this report, as this depends on which column cross section is selected and must be checked for the specific case. To arrive at the results, an in-depth literature study was conducted to gather information on the various issues and a calculation model in Excel was created. The calculation model was used to check how large the design load-bearing capacity is for transverse force absorption in a column base, but the checks were only made for non-prestressed joints. This is because prestressed joints also have other factors that affect the transverse resistance, outside the purpose and issue of the work. The Excel model is based on producing the results from calculation with nominal clamping force and comparing it with clamping force calculated with tightening torque. The results will be reported in the form of graphs and tables, where it will be possible to read the difference in the dimensioning load-bearing capacity for transverse force absorption in non-prestressed joints at nominal clamping force and clamping force calculated with tightening torque. The report shows a clear difference in results, where the nominal clamping force became significantly larger and this is supported by handbook on screw joints, as it is mentioned that “it is not possible to give an exact value of the coefficient of friction due to the large number of factors that affect ”, this means that the impact on the clamping force will be large.Det är vanligt förekommande att man använder sig av olika konstruktionsmaterial i kombination med varandra såsom betong, stål, trä och glas för att på så sätt kunna optimera byggnader. Syftet med detta är att minska vikt och öka belastningskapacitet, men det underlättar även montaget och minskar byggtiden. Pelarfötter av stål förankrade i betongfundament är ett exempel på en kombination av samverkansknutpunkter mellan stål och betongelement. I denna rapport studeras friktionen mellan underkant fotplatta och undergjutning, som är en funktion av pelarens normalkraft. Även friktionen som uppstår mellan fyrkantsbrickan och fotplattan kommer att undersökas som ett resultat av åtdragningsmomentet. Arbetet har lagt stor fokus på att diskutera för- och nackdelar med de olika metoderna för tvärkraftsupptagning i pelarfötter. Avgränsningar har gjorts, pelarens infästning till fotplåten har inte beaktats i denna rapport, eftersom detta är beroende av vilket pelartvärsnitt som är valt och måste kontrolleras för det specifika fallet. För att komma fram till resultaten utfördes en fördjupad litteraturstudie för att samla ihop information om de olika frågeställningarna och en beräkningsmodell i Excel skapades. Beräkningsmodellen användes för att kontrollera hur stor den dimensionerande bärförmågan är för tvärkraftsupptagning i en pelarfot, men kontrollerna görs endast för icke förspända förband. Detta eftersom förspända förband även har andra faktorer som påverkar tvärkraftskapaciteten, utanför arbetets syfte och frågeställning. Excel-modellen går ut på att ta fram resultaten ur beräkning med nominell spännkraft och jämföra den med spännkraft beräknad med åtdragningsmoment. Resultaten redovisas i form av grafer och tabeller, där man kan läsa av skillnaden i den dimensionerande bärförmågan för tvärkraftupptagning i icke förspända förband vid nominell spännkraft och spännkraft beräknad med åtdragningsmoment. Rapporten visar en tydlig skillnad i resultat, där den nominella spännkraften blev betydligt större och detta stöds av handbok om skruvförband, då det nämns att “det är inte möjligt att ge ett exakt värde på friktionskoefficienten på grund av det stora antalet faktorer som påverkar”, detta medför att inverkan på klämkraften blir stor.
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Smith, Kyle Mark. "Passive Force on Skewed Bridge Abutments with Reinforced Concrete Wingwalls Based on Large-Scale Tests." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/5577.
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Skewed bridges have exhibited poorer performance during lateral earthquake loading when compared to non-skewed bridges (Apirakvorapinit et al. 2012; Elnashai et al. 2010). Results from small-scale laboratory tests by Rollins and Jessee (2012) and numerical modeling by Shamsabadi et al. (2006) suggest that skewed bridge abutments may provide only 35% of the non-skewed peak passive resistance when a bridge is skewed 45°. This reduction in peak passive force is of particular importance as 40% of the 600,000 bridges in the United States are skewed (Nichols 2012). Passive force-deflection results based on large-scale testing for this study largely confirm the significant reduction in peak passive resistance for abutments with longitudinal reinforced concrete wingwalls. Large-scale lateral load tests were performed on a non-skewed and 45° skewed abutment with densely compacted sand backfill. The 45° skewed abutment experienced a 54% reduction in peak passive resistance compared to the non-skewed abutment. The peak passive force for the 45° skewed abutment was estimated to occur at 5.0% of the backwall height compared to 2.2% of the backwall height for the non-skewed abutment. The 45° skewed abutment displayed evidence of rotation, primarily pushing the obtuse side of the abutment into the backfill, significantly more than the non-skewed abutment as it was loaded into the backfill. The structural and geotechnical response of the wingwalls was also monitored during large-scale testing. The wingwall on the obtuse side of the 45° skewed abutment experienced nearly 6 times the amount of horizontal soil pressure and 7 times the amount of bending moment compared to the non-skewed abutment. Pressure and bending moment distributions are provided along the height of the wingwall and indicate that the maximum moment occurs approximately 20 in (50.8 cm) below the top of the wingwall. A comparison of passive force per unit width suggests that MSE wall abutments provide 60% more passive resistance per unit width compared to reinforced concrete wingwall and unconfined abutment geometries at zero skew. These findings suggest that changes should be made to current codes and practices to properly account for skew angle in bridge design.
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Horký, Karel. "Návrh setrvačníku jednovzpěrného čelisťového drtiče." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-400467.
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Diploma thesis deals with design of a flywheel and a belt pulley of single toggle jaw crusher DCJ 900x600. The first part is dedicated to overview of the methods for calculation of a size of flywheels for working machines. The second part is focused on calculation of a size of the flywheel. The third part treats the constructional design of the flywheel. In the last two parts there is elaborated analysis of a changing size of the flywheel depended on increasing the working rotation speed and change of coefficient .
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Emilia, Wallin. "Jämförelse av beräkningsmetoder för lastspridning i tvärled vid brobaneplattor av betong." Thesis, KTH, Betongbyggnad, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-169916.
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Denna studie har till syfte att undersöka hur lastfördelningen och följaktligen dimensionerande tvärkrafter och moment i brobaneplattor av betong skiljer sig åt beroende på val av beräkningsmetod. Jämförelsen sker primärt för tre utvalda handberäkningsmetoder som jämförts med beräkningar gjorda i ett beräkningsprogram baserat på finita elementmetoder (FEM). I jämförelsen undersöks hur laster sprids i brobaneplattan enligt de olika beräkningsmetoderna och vilka resulterande maximala snittkrafter som erhålls. Hur lastfördelningen sker är en komplex fråga och det är därför intressant att se vilka skillnader det blir i resultat utifrån olika beräkningsmetoder. Studien skedde på ett utvalt studieobjekt, en åtta meter bred samverkansbro i Njurunda strax söder om Sundsvall. De trafiklaster som beaktats är lastmodell 1 och lastmodell 2 enligt Eurokod (CEN, 2003). De beräkningsmetoder som jämförts i den här studien är dels en metod för beräkning av tvärgående konsolmoment där kantbalken bidrar mycket till den lastspridande effekten. En annan metod är för beräkning av tvärkraftsfördelning vilken generellt anses mycket gynnsam, alltså ger små tvärkrafter att dimensionera bron utifrån. Den tredje och sista handberäkningsmetoden som studerats är beräkningar av tvärgående moment i fältmitt, med hjälp av influensytediagram. Influensytediagrammen som dessa studier baseras på är framtagna av Adolf Pucher (Pucher, 1977) och kallas ibland för Pucherdiagram. Finita elementmodeller (FE-modeller) skapades för jämförelse av resultat från handberäkningar. Flera olika FE-modeller skapades med varierande detaljnivå, för att kunna se hur modelleringstekniken påverkar resultatet. I alla FE-modeller har brobaneplattan modellerats som skalelement eftersom detta är det vanligaste sättet att modellera en bro med FEM. Skillnaderna mellan de olika FE-modellerna är framför allt hur huvudbalkarna modellerats. Även ytterligare en handberäkningsmetod tillämpades för respektive snittkraft för att ge ytterligare en referens. Referensmetoderna valdes för att vara enklare metoder som baseras på andra randvillkor än de primära handberäkningsmetoderna i den här studien. Resultatet från studien visar att de förenklingar som finns i handberäkningar kan ha signifikant inverkan på resultatet. Ett konstant förhållande mellan handberäkning och FEM, där den ena beräkningsmetoden alltid resulterade i större snittkrafter, kunde inte konstateras rakt igenom studien. För tvärgående konsolmoment gav handberäkningen ett större maxmoment samt att en del skillnader kunde avläsas FE-modellerna emellan. Vid beräkning av tvärkraft gav FE-beräkningen ett resultat som var nära på det dubbla av det resultat handberäkningen gav. För Pucherdiagrammen blev resultaten varierade och det fanns ingen tydlig indikation för om handberäkningar ger större eller mindre tvärgående moment än en FE-modell. Studien resulterade bland annat i ökad kunskap om att förenklingar, vid dimensionering av en bro med hjälp av handberäkningar, kan ha stor betydelse för resultatet. Då förenklingar vid handberäkning inte går att välja av användaren finns en fördel med FEM. Fördelen med FEM är då att förenklingar styrs av användaren och det går även att studera vilken effekt en viss förenkling ger. En annan slutsats var att betong är ett material som har ett komplext beteende och i metoder som bygger på empiriska studier kan lättare få med olika effekter som finns i en verklig brobaneplatta av betong.The aim of this thesis is to study different design methods for determing load distribution, and design values for shear force and bending moment in concrete bridge decks. The study was performed based on three design methods for hand calculations, which have been compared to the results from finite element modelling (FEM). The load distribution has a major impact on the design of a bridge and how the results from different design methods will correlate is of a great interest. The evaluation has been performed on one case study, wich is an eight-meter wide composite girder bridge in Njurunda, situated south of Sundsvall in Sweden. The traffic loads applied for this study was load model 1 and load model 2 prescribed in Eurocode (CEN, 2003). One of the design methods investigated is a method used to determine for bending moment for a cantilever slab. A significant impact from the edge beam utilizes by the method to calculate the bending moment. The second method is a design method for shear forces recommended by The Swedish Transport Administration. The third and last design methods for hand calculation is to use influence charts by Pucher (Pucher, 1977). By using the influence chart to calculate the maximum bending moment in mid-span. Results from different models, created with FEM, were compared to the results from hand calculations. The bridge slab was modelled with shell elements, and the girders of the bridge were modelled in four different ways to study the impact of the level of detail in the numerical models. The results in this report show that hand calculation methods are based on significant simplifications of the structure and these may have a major impact on the results. The relation between results from hand calculation methods and results obtained with FEM was not consistent in all cases analysed. While studying the bending moment for a cantilever slab, the main conclusion was that the simplifications in the hand calculation methods resulted in significantly higher moments compared to the FE-calculations. Regarding design for shear forces, the FE analyses resulted in nearly twice as high shear forces compared to the hand calculation methods. While using the influence charts by Pucher the relation between results from hand calculations and results from FEM was not consistent. Conclusions from the study included that the simplifications in hand calculations is hard to change. These simplifications can have a major influence to the results. Some simplifications will make the results more on the safe side. With FEM the user is more free to choose which simplifications that will be made, but it can sometimes be hard to see the effect simplifications have on the results. Concrete is a complex material and design methods based on empirical studies does most likely give a result that reflects the reality better than methods based on mathematic theories.
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Lidmila, Ladislav. "Rekonstrukce mostu v Ledči nad Sázavou." Master's thesis, Vysoké učení technické v Brně. Fakulta stavební, 2020. http://www.nusl.cz/ntk/nusl-409797.
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Diploma thesis deals with reconstruction of old beam bridge in town Ledeč nad Sázavou. Three variants of reconsttruction were done. Detailed structural design report was done to one of them, streithening with post-tensioning. Calculation of load effect was solved with finite elemet method via software on grillage model. Construction was checked on ultimate limit state and serviceability limit state. Necessary drawings were elaborated to chosen method.
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Martin, Ramaldo S. "Implementation and validation of a computational model of the feline forelimb." Diss., Georgia Institute of Technology, 2013. http://hdl.handle.net/1853/50293.
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Postural control incorporates multiple neural and mechanical systems at various levels of the motor control system, yet the question of how all these systems interact remains unanswered. This dissertation describes development of a biologically based, three-dimensional mathematical model of the forelimb of the domestic cat that integrates skeletal anatomy, muscular architecture, and neural control. Previous work has shown that muscle architecture profoundly affects its function. However, even though the forelimbs of quadrupeds contribute to posture and locomotion differently from hindlimbs, most models of quadruped motion are based upon hindlimb mechanics. The proposed work consists of three main steps: (1) architectural and anatomical characterization, which involves acquisition of muscle attachment data, measurement of whole muscle and muscle fiber properties, and estimation of limb kinematic parameters; (2) model development and implementation, wherein the data will be integrated into a mathematical model using special-purpose software; and (3) model validation, including verification of model estimates against experimentally obtained measurements of muscle moment arms, and prediction of limb kinetics, namely end-point forces arising from perturbations to the limb. It was found that the forelimb does indeed possess structure, particularly at the shoulder and antebrachium, that allows for more diverse movements. The neural wiring in these regions is more complex than in the hindlimb, and there exists substantial muscular structure in place for non-sagittal motion and object suppression and retrieval. Other results showed that the kinematics of the limb alone produce a restorative response to postural disturbance but that the magnitude is reduced, indicating that neural input acts as a modulatory influence on top of the intrinsic mechanism of limb architecture. Furthermore the model demonstrated many of the essential features found in the experiments. This study represents the implementation of the first forelimb model of the cat incorporating mechanical properties and serves as a key component of a full quadruped model to explore posture and locomotion.
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Lemaire, Alexandra. "Lombalgies chroniques : évaluation des facteurs mécaniques des membres inférieurs au moyen des relations moment-vitesse." Thesis, Le Mans, 2014. http://www.theses.fr/2014LEMA1024/document.
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La lombalgie est un problème de santé public induisant de nombreuses répercussions sur le plan économique et social. Le passage à la chronicité concerne moins de 10% des lombalgies, mais représente 85% des coûts liés à la prise en charge de cette pathologie. Dans ce contexte, il parait indispensable de pouvoir optimiser les programmes de réentrainement à l’effort du lombalgique chronique afin de les rendre le plus efficace et le plus pertinent possible. Ce travail de thèse a pour objectif d’évaluer les facteurs mécaniques des membres inférieurs au moyen des relations moment-vitesse dans des conditions isocinétiques. Dans une première étude, nous avons évalué les muscles extenseurs du genou et les muscles fléchisseurs et extenseurs du tronc chez des sujets lombalgiques et des sujets sains. Nous avons, ainsi mis en évidence une faiblesse significative au niveau de la force et de la puissance des muscles extenseurs du genou chez les sujets lombalgiques associée à la faiblesse musculaire du tronc classiquement évoquée pour cette population. Après avoir mis en place, dans une seconde étude, un protocole d’évaluation permettant d’établir des relations moment- et puissance-vitesse pour les muscles extenseurs et fléchisseurs de la hanche, nous avons évalué la force et la puissance de ces groupes musculaires chez des sujets lombalgiques. Les résultats ont, comme pour la première étude, mis en avant une faiblesse significative au niveau de la force et de la puissance de ces groupes musculaires, par rapport à des sujets sains, avec un déficit plus marqué au niveau des extenseurs, comme pour le tronc. L’ensemble des résultats obtenus dans le cadre de ce travail de thèse démontre qu’il est important de proposer un travail de force et de puissance au niveau des membres inférieurs pour les patients lombalgiques chroniques afin de mieux lutter contre le syndrome de déconditionnement qui touche l’ensemble des chaines musculaires des patientsLow back pain is a public health problem inducing economical and social consequences. Chronicity involves less than 10% of low back pain, but represents 85% of the total costs related to this pathology. In this context, it seems essential to optimize chronic low back pain rehabilitation programs to make them more effective and relevant. The purpose of this phD was then to evaluate lower limbs mechanical factors using torque- and power-velocity relationships. In a first study, knee extensors muscles and trunk flexor and extensor muscles were evaluated in chronic low back pain and healthy subjects. A significant knee extensor strength and power weakness weas observed for chronic low back pain subjects, associated with the typical trunk weakness referred to this population. The second study focused on establishing a protocol allowing assessing hip flexor and extensor torque- and power-velocity relationships. This protocol was then applied to evaluate flexor and extensor hip muscles in chronic low back pain subjects. Results, in accordance with the first study, highlighted a significant strength and power weakness for hip muscle groups in chronic low back pain relative to healthy subjects, with a greater hip extensor deficit, as it is generally observed for the trunk.In conclusion, these different studies showed the importance of proposing torque and power lower limbs rehabilitation for chronic low back pain patients to better fight against the deconditioning syndrome that affects all muscular chains in this population