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周婉娥 and Wan-E. Zhou. "The dynamic stiffness method." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1996. http://hub.hku.hk/bib/B31235487.
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Leung, A. Y. T. "Dynamic stiffness and substructures." Thesis, Aston University, 1993. http://publications.aston.ac.uk/21737/.
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Zhou, Wan-E. "The dynamic stiffness method /." Hong Kong : University of Hong Kong, 1996. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19668612.
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Alley, Ferryl. "Dynamic ankle stiffness during upright standing." Thesis, McGill University, 2012. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=110417.
Повний текст джерелаАнотація:
Studies of upright stance commonly model its biomechanics as an inverted pendulum, defining an overall postural stiffness, generated by the ankle joints, needed to overcome gravity's destabilizing effects. This model assumes symmetric left and right ankle stiffness, fixed throughout upright stance. However, the relative contributions of the intrinsic and reflex components of dynamic stiffness and how lower limbs interact during upright standing is not well understood. This thesis estimated the dynamic stiffness in both ankles simultaneously during upright standing and examined coordination between the two limbs. During bilateral perturbation trials, where angular position perturbations were applied to both ankles simultaneously, a strong intrinsic and reflex response was observed. For all subjects, intrinsic stiffness was lower than the required postural stiffness to maintain standing. Dynamic ankle stiffness also changed for different levels of postural sway torque, such that intrinsic and reflex stiffness was higher during forward lean and lower when leaning back. Contralateral responses were observed between input ankle position and the torques generated from the opposite ankle. These findings suggest that the overall postural control is not a simple summation of independent, fixed intrinsic stiffness responses from individual ankles. Intrinsic elastic stiffness is not sufficient for maintaining balance and contributing stiffness pathways are modulated throughout upright standing sway. Upright standing models must incorporate dynamic ankle stiffness measurements, variable stiffness parameters, and interactions between each supporting limbs.Les études de la posture érigée sont couramment fondées sur le modèle biomécanique du pendule inversé définissant une raideur posturale générale produite par les articulations des chevilles et nécessaire pour compenser les effets déstabilisants de la gravité. Ce modèle est basé sur l'hypothèse d'une raideur symétrique des chevilles gauche et droite qui demeure fixe pendant la tenue de la posture érigée. Toutefois, les contributions relatives des composantes intrinsèques et réflexes de la raideur dynamique ainsi que l'interaction des membres inférieurs pendant la position érigée debout ne sont pas bien comprises. Ce mémoire fait état d'une estimation de la raideur dynamique des deux chevilles simultanément durant la position érigée debout, ainsi que d'une étude de la coordination entre les deux membres. Au cours de tests de perturbation bilatérale, pendant lesquels des perturbations de la position angulaire ont été appliquées aux deux chevilles simultanément, une nette réponse intrinsèque et réflexe a été observée. Chez tous les sujets, la raideur intrinsèque était inférieure à la raideur posturale nécessaire pour maintenir la station debout. La raideur dynamique des chevilles a également évolué en fonction de différents niveaux du couple du balancement postural, de telle sorte que la raideur intrinsèque et réflexe était plus élevée pendant l'inclinaison avant et moins élevée pendant l'inclinaison arrière. Des réponses controlatérales ont été observées entre la position de départ de la cheville et les couples générés depuis la cheville opposée. Ces résultats donnent à penser que le contrôle postural général ne consiste pas en la simple sommation de réponses indépendantes fixes de raideur intrinsèque des chevilles individuelles. La raideur élastique intrinsèque ne suffit pas pour maintenir l'équilibre, et les voies de raideur contributives sont modulées pendant le balancement de la position érigée debout. Les modèles de la position érigée debout doivent intégrer des mesures de la raideur dynamique des chevilles, des paramètres variables de la raideur et des interactions entre les membres d'appui.
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郭騰川 and Tang-chuen Nick Kwok. "Dynamic stiffness method for curved structures." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1995. http://hub.hku.hk/bib/B31212359.
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Kwok, Tang-chuen Nick. "Dynamic stiffness method for curved structures /." Hong Kong : University of Hong Kong, 1995. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19672421.
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Vega, González Myraida Angélica. "Dynamic study of tunable stiffness scanning microscope probe." Thesis, Massachusetts Institute of Technology, 2005. http://hdl.handle.net/1721.1/32967.
Повний текст джерелаАнотація:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2005.Includes bibliographical references (leaf 31).
This study examines the dynamic characteristics of the in-plane tunable stiffness scanning microscope probe for an atomic force microscope (AFM). The analysis was carried out using finite element analysis (FEA) methods for the micro scale device and its macro scale counterpart, which was designed specifically for this study. Experimental system identification testing using sound wave and high-speed camera recordings was clone on the macro scale version to identify trends that were then verified in the micro scale predictions. The results for the micro scale device followed the trends predicted by the macro scale experimental data. The natural frequencies of the device corresponded to the three normal directions of motion, in ascending order from the vertical direction, the out-of- plane direction, and the horizontal direction. The numerical values for these frequencies in the micro scale are 81.314 kHz, 51.438 kHz, and 54.899 kHz for the X, Y, and Z directions of vibration respectively. The error associated with these measurements is 6.6% and is attributed to the high tolerance necessary for measurements in the micro scale, which was not matched by the macro scale data acquisition methods that predict the natural frequency range.
(cont.) The vertical vibrations are therefore the limiting factor in the scanning speed of the probe across a sample surface, thus requiring the AFM to scan at an effective frequency of less than 81.3 kHz to avoid resonance.
by Myraida Angélica Vega González.
S.B.
8
Garcia, Maria-José. "Engineering rubber bushing stiffness formulas including dynamic amplitude dependence." Licentiate thesis, KTH, Aeronautical and Vehicle Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4017.
Повний текст джерелаАнотація:
Engineering design models for the torsion and axial dynamic stiffness of carbon black filled rubber bushings in the frequency domain including amplitude dependence are presented. They are founded on a developed material model which is the result of applying a separable elastic, viscoelastic and friction rubber component model to the material level. Moreover, the rubber model is applied to equivalent strains of the strain states inside the torsion or axial deformed bushing previously obtained by the classical linear theory of elasticity, thus yielding equivalent shear moduli which are inserted into analytical formulas for the stiffness. Therefore, unlike other simplified approaches, this procedure includes the Fletcher-Gent effect inside the bushing due to non-homogeneous strain states. The models are implemented in Matlab®. In addition, an experimental verification is carried out on a commercially available bushing thus confirming the accuracy of these models which become a fast engineering tool to design the most suitable rubber bushing to fulfil user requirements. Finally, they can be easily employed in multi-body and finite element simulations
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Garcia, Maria-José. "Engineering rubber bushing stiffness formulas including dynamic amplitude dependence /." Stockholm : Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4017.
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Carrella, Alessandro. "Passive vibration isolators with high-static-low-dynamic-stiffness." Thesis, University of Southampton, 2008. https://eprints.soton.ac.uk/51276/.
Повний текст джерелаАнотація:
In many engineering applications there is need to reduce the level of vibrations that are transmitted from a source to a receiver. Amongst several different techniques, the most commonly adopted solution is to interpose an isolation mount between the source and the receiver. Ideally, a vibration isolation mount would have a high static stiff- ness to prevent too large a static displacement to occur, but a low dynamic stiffness which reduces the natural frequency and extends the frequency range of isolation. For linear mounts these two features are mutually exclusive. However, an improved com- promise can be reached by employing nonlinear mounts. In this thesis the advantages and the limitations of nonlinear isolation mechanisms with a high-static-low-dynamic- stiffness(HSLDS) characteristic are investigated. A study of the static characteristics of two mechanisms with HSLDS is presented. This desired property is obtained by connecting in parallel elements with positive and negative stiffness. For both systems the positive stiffness is given by linear springs. In one model the geometry of the system is exploited to achieve the desired negative stiffness. This is obtained by a pair of linear springs placed at a certain angle to the horizontal (oblique springs). In the second model considered the required negative stiffness is provided by a set of magnets in attracting configuration. In both cases the force and stiffness are approximated to a symmetric cubic polynomial and a quadratic function of the displacement respectively. From a dynamical point of view this allows the system to be treated as a Duffing oscillator. It is argued that for small oscillations about the static equilibrium position the mechanism behaves linearly. A lab-scale rig which reproduces the HSLDS system with magnets and springs is designed and built. The excitation level is chosen to comply with the assumption of small displacement so that the experimental results show that the system responds in a rather linear fashion. The natural frequency of the HSLDS is half that of a linear model with the same static displacement and its transmissibility also compares favourably. A nonlinear analysis is also carried out in order to predict the response of the system when the assumption of linearity no longer holds true. Both cases of harmonic excita- tion of the payload and of the base are studied. For the two instances an approximate solution to the nonlinear equation of motion is found by applying the method of Har- monic Balance to a first order expansion. The main feature of the dynamic response of a Duffing oscillator is the jump phenomenon. Herein this is described and analyt- ical expressions for the jump frequencies are also provided. The isolation properties of an HSLDS isolation system are evaluated in terms of the transmissibility and its performance is compared with that of an equivalent linear system. It is shown that the HSLDS has a higher isolation capability.
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Johnson, Stephanie. "Pediatric Dynamic Shoulder Stiffness Predicted From Quasi-Static Impacts." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1483704973274323.
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Berggren, Eric. "Railway Track Stiffness : Dynamic Measurements and Evaluation for Efficient Maintenance." Doctoral thesis, KTH, Farkost och flyg, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10360.
Повний текст джерелаАнотація:
Railway track stiffness (vertical track load divided by track deflection) is a basic parameter oftrack design which influences the bearing capacity, the dynamic behaviour of passing vehiclesand, in particular, track geometry quality and the life of track components. Track stiffness is abroad topic and in this thesis some aspects are treated comprehensively. In the introductionpart of the thesis, track stiffness and track stiffness measurements are put in their propercontext of track maintenance and condition assessment. The first aspect is measurement of track stiffness. During the course of this project, Banverkethas developed a new device for measurement of dynamic track stiffness called RSMV(Rolling Stiffness Measurement Vehicle). The RSMV is capable of exciting the trackdynamically through two oscillating masses above one wheelset. The dynamic stiffness is acomplex-valued quantity where magnitude is the direct relation between applied load anddeflection (kN/mm) and phase is a measure of deflection-delay by comparison with force. Thephase has partial relationship with damping properties and ground vibration. The RSMVrepeatability is convincing and both overall measurements at higher speeds (up to 50 km/h)and detailed investigations (below 10 km/h) can be performed. The measurement systemdevelopment is described in Paper A and B. The second aspect is evaluation of track stiffness measurements along the track from a trackengineering perspective. Actual values of stiffness as well as variations along the track areimportant, but cannot always answer maintenance and design related questions alone. InPaper D track stiffness is studied in combination with measurements of track geometryquality (longitudinal level) and ground penetrating radar (GPR). The different measurementsare complementary and a more reliable condition assessment is possible by the combinedanalysis. The relation between soft soils and dynamic track stiffness measurements is studiedin Paper C. Soft soils are easily found and quantified by stiffness measurements, in particularif the soft layer is in the upper part of the substructure. There are also possibilities to directlyrelate substructure properties to track stiffness measurements. Environmental vibrations areoften related to soft soils and partly covered in Paper C. One explanation of the excitationmechanism of train induced environmental vibrations is short waved irregular supportconditions. This is described in Paper E, where track stiffness was evinced to have normalvariations of 2 – 10 % between adjacent sleepers and variations up to 30 % were found. Anindicative way of finding irregular support conditions is by means of filtering longitudinallevel, which is also described in the paper. Train-track interaction simulation is used in PaperH to study track stiffness influence on track performance. Various parameters of trackperformance are considered, e.g. rail sectional moment, rail displacement, forces at wheel-railinterface and on sleepers, and vehicle accelerations. Determining optimal track stiffness froman engineering perspective is an important task as it impacts all listed parameters. The third aspect, efficient maintenance, is only partially covered. As track stiffness relates toother condition data when studied from a maintenance perspective, vertical geometricaldefects (longitudinal level and corrugation/roughness) are studied in paper F. The generalmagnitude dependency of wavelength is revealed and ways of handling this in conditionassessment are proposed. Also a methodology for automated analysis of a large set ofcondition data is proposed in Paper G. A case study where dynamic track stiffness,longitudinal level and ground penetrating radar are considered manifests the importance oftrack stiffness measurements, particularly for soil/embankment related issues.QC 20100623
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Cheng, Yongming 1964. "Dynamic stiffness and transfer matrix analysis of marine riser vibration." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/107859.
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Yuan, Han. "Static and dynamic stiffness analysis of cable-driven parallel robots." Thesis, Rennes, INSA, 2015. http://www.theses.fr/2015ISAR0003/document.
Повний текст джерелаАнотація:
Cette thèse contribue à l'analyse des raideurs statique et dynamique des robots parallèles à câbles dans un objectif d'amélioration de la précision de positionnement statique et de la précision de suivi de trajectoire. Les modélisations statique et dynamique proposées des câbles considèrent l'effet du poids du câble sur son profil et l'effet de masse du câble sur la dynamique de ce dernier. Sur la base du modèle statique de câble proposé, l'erreur de pose statique au niveau de l'organe terminal du robot est définie et sa variation en fonction de la charge externe appliquée est utilisée pour évaluer la raideur statique globale de la structure. Un nouveau modèle dynamique vibratoire de robots à câbles est proposé en considérant le couplage de la dynamique des câbles avec les vibrations de l'organe terminal. Des validations expérimentales sont réalisées sur des prototypes de robots à câbles. Une série d'expériences de statique, d'analyses modales, d'analyses en régime libre et de suivi de trajectoire sont réalisées. Les modèles statiques et dynamiques proposés sont confirmés. Les dynamiques des câbles et du robot ainsi que leur couplage sont discutées montrant la pertinence des modèles développés pour l’amélioration des performances des robots à câbles en termes de design et le contrôle. Outre l'analyse des raideurs statique et dynamique, les modèles proposés sont appliqués dans l'amélioration du calcul de la distribution des efforts dans les câbles des robots redondants. Une nouvelle méthode de calcul de la distribution des efforts dans les câbles basée sur la détermination de la limite inférieure des forces dans les câbles est présentée. La prise en compte de la dépendance à la position dans l'espace de travail permet de limiter les efforts dans les câbles et ainsi d'améliorer l'efficience des robots d'un point de vue énergétiqueThis thesis contributes to the analysis of the static and dynamic stiffness of cable-driven parallel robots (CDPRs) aiming to improve the static positioning accuracy and the trajectory tracking accuracy. The proposed static and dynamic cable modeling considers the effect of cable weight on the cable profile and the effect of cable mass on the cable dynamics. Based on the static cable model, the static pose error of the end-effector is defined and the variation of the end-effector pose error with the external load is used to evaluate the static stiffness of CDPRs. A new dynamic model of CDPRs is proposed with considering the coupling of the cable dynamics and the end-effector vibrations. Experimental validations are carried out on CDPR prototypes. Static experiments, modal experiments, free vibration experiments and trajectory experiments are performed. The proposed static and dynamic models are verified. Cable dynamics, robot dynamics and their coupling are discussed. Results show the relevance of the proposed models on improving the performances of CDPRs in terms of design and control. Besides stiffness analysis, the proposed models are applied on the force distribution of redundant actuated CDPRs. A new method on the calculation of the cable forces is proposed, where the determination of the lower-boundary of the cable forces is presented. The consideration of the pose-dependence of the lower force boundary can minimize the cable forces and improve the energy efficiency of CDPRs
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El-Tayeb, Nabil Said Mohamed. "The dynamic properties of ball bearings." Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366386.
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Black, Thomas Andrew. "Spectral Element Analysis of Bars, Beams, and Levy Plates." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/33260.
Повний текст джерелаАнотація:
This thesis is primarily concerned with the development and coding of a Levy-type spectral plate element to analyze the harmonic response of simply supported plates in the mid to high frequency range. The development includes the governing PDE, displacement field, shape function, and dynamic stiffness matrix. A two DOF spectral Love bar element and both a four DOF spectral Euler-Bernoulli and a four DOF spectral Timoshenko beam element are also developed to gain insight into the performance of spectral elements.
A cantilever beam example is used to show how incorporating eigenfunctions for the dynamic governing PDE into the displacement field enables spectral beam elements to represent the structural dynamics exactly. A simply supported curved beam example is used to show that spectral beam elements can converge the effects of curved geometry with up to a 50% reduction in the number of elements when compared to conventional FE. The curved beam example is also used to show that the rotatory inertia and shear deformation, from Timoshenkoâ s beam theory, can result in up to a 28% shift in natural frequency over the first three bending modes.
Finally, a simply supported Levy-plate model is used to show that the spectral Levy-type plate element converges the dynamic solution with up to three orders of magnitude fewer DOF then the conventional FE plate formulation. A simply-supported plate example problem is used to illustrate how the coefficients of the Fourier series expansion can be used as edge DOF for the spectral Levy-plate element. The Levy-plate element development gives insight to future research developing a general spectral plate element.Master of Science
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Black, T. Andrew. "Spectral Element Analysis of Bars, Beams, and Levy Plates." Thesis, Virginia Tech, 2005. http://hdl.handle.net/10919/33260.
Повний текст джерелаАнотація:
This thesis is primarily concerned with the development and coding of a Levy-type spectral plate element to analyze the harmonic response of simply supported plates in the mid to high frequency range. The development includes the governing PDE, displacement field, shape function, and dynamic stiffness matrix. A two DOF spectral Love bar element and both a four DOF spectral Euler-Bernoulli and a four DOF spectral Timoshenko beam element are also developed to gain insight into the performance of spectral elements.
A cantilever beam example is used to show how incorporating eigenfunctions for the dynamic governing PDE into the displacement field enables spectral beam elements to represent the structural dynamics exactly. A simply supported curved beam example is used to show that spectral beam elements can converge the effects of curved geometry with up to a 50% reduction in the number of elements when compared to conventional FE. The curved beam example is also used to show that the rotatory inertia and shear deformation, from Timoshenkoâ s beam theory, can result in up to a 28% shift in natural frequency over the first three bending modes.
Finally, a simply supported Levy-plate model is used to show that the spectral Levy-type plate element converges the dynamic solution with up to three orders of magnitude fewer DOF then the conventional FE plate formulation. A simply-supported plate example problem is used to illustrate how the coefficients of the Fourier series expansion can be used as edge DOF for the spectral Levy-plate element. The Levy-plate element development gives insight to future research developing a general spectral plate element.Master of Science
18
Miller, Joel Christopher. "Modulating dynamic stiffness of a direct-drive brushless linear DC motor." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/16103.
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Andersson, Patrik. "Finite Element and Dynamic Stiffness Analysis of Concrete Beam-Plate Junctions." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-198509.
Повний текст джерелаАнотація:
Measurements and predictions of railway-induced vibrations are becoming a necessity in today’s society where land scarcity causes buildings to be put close to railway traffic. The short distances mean an increased risk of the indoor vibration and noise disturbances experienced by residents. In short, the scope of the project is to investigate the transmission loss and vibration level decrease across various junction geometries. The junctions are modelled in both the Finite Element Method (FEM) and the Dynamic Stiffness Method (DSM). Resonances are avoided when possible by using semi-infinite building components. A two-dimensional model that included Timoshenko beams was set up by Wijkmark [1] and solved using the variational formulation of the DSM by Finnveden [2]. The model is efficient and user-friendly but there is no easy way to adjust the junction geometry since the depths of the walls and the floor slabs are the same. From that study, the current topic was formulated. The results presented in this paper indicate that both the Euler-Bernoulli DS model and the three-dimensional FE model have good potential in describing the vibration transmission across the different junction geometries. The two modelling types show more similar results in the analyses of the bending wave attenuation than in the analyses of the quasilongitudinal wave attenuation. One of the probable causes is that the set length of the Perfectly Matched Layers (PML) is not sufficient at such low frequencies. Larger PMLs require bigger geometries that lead to an increase of the computational time. The other proposed reason is the fact that bending waves are created above the asymmetrical junction when the lower beam is excited by a vertical harmonic force. The flexural displacements are neglected in those cases. The results however, were good enough to be satisfactory. Three junction models were investigated and the attenuation is the highest for both wave types in the case with a beam pair attached to the “middle” of an infinite plate. The attenuation is the second highest across the edge of a semi-infinite plate and the lowest across a junction corner of a semi-infinite plate. As part of the suggested future work, the wave transmission between beam and plate needs to be investigated when Timoshenko beams are included in the DS model. In the Euler-Bernoulli beam theory the cross-section remains perpendicular to the beam axis, which is different to the behaviour of solid elements in FEM.
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HYLOK, JEFFERY EDWARD. "EXPERIMENTAL IDENTIFICATION OF DISTRIBUTED DAMPING MATRICES USING THE DYNAMIC STIFFNESS MATRIX." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1029527404.
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Winstead, Michael. "Translation of L and S Band Tracking Assets to X Band High Dynamic Testing." International Foundation for Telemetering, 2006. http://hdl.handle.net/10150/603933.
Повний текст джерелаАнотація:
ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, CaliforniaRecent Constraints on the use of L and S band spectrum led to the search for additional Frequency Domain Bandwidth augmentation for test range telemetry needs. The ITU (International Telecommunications Union) approved X band region is listed as 7000 MHz to 8500 MHz for telemetry space applications. Bandwidth is available within this domain subject to the WARC (World Administrative Radio Consortium) approvals. This paper describes tests and presents results illustrating methodology that is available, and which can be used for conversion of S-band assets to the X band spectral region.
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Pasha, Hasan G. "Estimation of Static Stiffnesses from Free Boundary Dynamic (FRF) Measurements." University of Cincinnati / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1416569956.
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Roach, M. P. "Vibration control in rotating machinery using variable dynamic stiffness hydrostatic squeeze-films." Thesis, Staffordshire University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.254234.
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Stenholm, Roland. "Time-Multiplexed Channel Switches for Dynamic Frequency Band Reallocation." Thesis, Linköpings universitet, Datorteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-128793.
Повний текст джерелаАнотація:
A partially parallel reconfigurable channel switch is constructed for use in DFBR. Its permutation can be changed while running without any interruption in the streams of data. Three approaches are tried: one based on asorting network, one based on memories and multiplexers and one based on a Clos network. Variants with the pattern stored in memories and in shift registers are tried. They are implemented in automatically generated Verilog and synthesized for an FPGA. Their cost in terms of area use, memory use and maximum clock frequency is compared and the results show that the Clos based approach is superior in all aspects and that pattern data should not be saved in shift registers. The work is open source and available for download at https://github.com/channelswitch/channelswitch.En delvis parallel och delvis seriell kanalswitch för användning inom DFBR skapas. Dess permutation kan ändras medan den kör utan avbrott i dataströmmen. Tre alternativ undersöks: ett baserat ett sorteringsnätverk, ett baserat på minnen och multiplexrar och ett som baseras på Clos-nätverk. Versioner med mönsterdata sparad i skiftregister och i minnen prövas. De implementeras i automatiskt genererad Verilog och synthesiseras för en FPGA. Deras kostnad i areaanvändning, minnesanvändning och maximal klockfrekvens jämförs. Resultaten visar i princip att Clos-nätverken är bäst i alla avseenden och att mönsterdata ska sparas i RAM-minnen och inte i skiftregister. Arbetet är open source och kan laddas ner från https://github.com/channelswitch/channelswitch.
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Randle, Andrew Martin. "Dynamic radio channel effects from L-band foliage scatter." Thesis, University of York, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341630.
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Maolin, Liao. "Dynamic methods of stiffness identification in impacting systems for rotary-percussive drilling applications." Thesis, University of Aberdeen, 2016. http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=230156.
Повний текст джерелаАнотація:
Stiffness identification of an impacted constraint is the main issue discussed in this thesis. Primarily, a change of stability (bifurcation) is used to determine the dynamical stiffness of an impacted beam for a piecewise-linear impact oscillator. Detailed one- and two-parameter bifurcation analyses of this impacting system are carried out by means of experiments and numerical methods. Particularly, the two-parameter numerical continuation of the obtained codimension-one bifurcation (period-doubling bifurcation, or fold bifurcation) indicates a strong monotonic correlation between the stiffness of the impacted beam and the frequency at which this bifurcation appears. In addition to the bifurcation techniques, another method for stiffness identification is analysis of impact duration. To accurately detect impact durations from numerical or experimental signals, nonlinear time series methods are utilised. Two impacting systems, including the piecewise-linear impact oscillator and a drillbit-rock vibro-impact system, are studied to demonstrate this proposed method. For either system, the impact duration is relatively constant when the response of oscillator is a period-one one-impact motion, and it is approximated as a half of the natural period of the oscillator-constraint system. When the mass of oscillator is constant, for an impacted constraint with a certain stiffness, the higher the stiffness, the lower the impact duration. This monotonic correlation provides another mechanism to estimate the stiffness of the impacted constraint. Based on the developed two dynamical methods for stiffness identification, a control algorithm for parameter adjustment of the axial vibration for rotary-percussive drilling applications is designed. This control algorithm aims to maintain the optimal drilling state under the varying formations. By this way, the efficiency of rotary-percussive drilling is expected to be promoted.
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Berggren, Eric. "Dynamic track stiffness measurement : a new tool for condition monitoring of track substructure /." Stockholm, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-341.
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Kareaga, Laka Zorion. "Dynamic stiffness and damping prediction on rubber material parts, FEA and experimental correlation." Thesis, London Metropolitan University, 2016. http://repository.londonmet.ac.uk/1125/.
Повний текст джерелаАнотація:
The final objective of the present work is the accurate prediction of the dynamic stiffness behaviour of complex rubber parts using finite element simulation tools. For this purpose, it becomes necessary to perform a complex rubber compound material characterisation and modelling work; this needs two important previous steps. These steps are detailed in the present document together with a theoretical review of viscoelastic visco-elasto-plastic models for elastomers. Firstly, a new characterisation method is proposed to determine the degree of cure of rubber parts. It is known that the degree of cure of rubbers bears heavily on their mechanical properties. This method consists of the correlation of swelling results to rheometer data achieving a good agreement. Secondly, the influence of the strain rate used in static characterisation tests is studied. In this step, a new characterisation method is proposed. The latter characterisation method will be used to fit extended hyperelastic models in Finite Element Analysis (FEA) software like ANSYS. The proposed method improves the correlation of experimental data to simulation results obtained by the use of standard methods. Finally, the overlay method proposed by Austrell concerning frequency dependence of the dynamic modulus and loss angle that is known to increase more with frequency for small amplitudes than for large amplitudes is developed. The original version of the overlay method yields no difference in frequency dependence with respect to different load amplitudes. However, if the element in the viscoelastic layer of the finite element model are given different stiffness and loss properties depending on the loading amplitude level, frequency dependence is shown to be more accurate compared to experiments. The commercial finite element program Ansys is used to model an industrial metal rubber part using two layers of elements. One layer is a hyper viscoelastic layer and the other layer uses an elasto-plastic model with a multi-linear kinematic hardening rule. The model, being intended for stationary cyclic loading, shows good agreement with measurements on the harmonically loaded industrial rubber part.
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Li, Xiaoming. "The effect of stiffness and mass on the dynamic response of wood floors." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-06112009-063311/.
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Smith, Jeremy Richard Denham. "Statistical energy analysis of marine structures with periodic and near-periodic components." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287051.
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Wang, Narisi. "X-band class-E power amplifiers with dynamic bias control." Diss., Connect to online resource, 2006. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3218998.
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Lewandowski, Cyprian(Cyprian Krzysztof). "Dynamic polarizability and collective modes in narrow-band electron systems." Thesis, Massachusetts Institute of Technology, 2020. https://hdl.handle.net/1721.1/130218.
Повний текст джерелаАнотація:
Thesis: Ph. D., Massachusetts Institute of Technology, Department of Physics, May, 2020Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 114-123).
The family of moiré materials, in particular the magic angle twisted bilayer graphene, has emerged recently as a platform to study strongly interacting physics. This thesis analyzes the impact of the ultranarrow Bloch bands and strong electron-electron interactions on the dynamical polarization response of these systems. Strong interactions alter the collective charge dynamics in a number of interesting ways, in particular by stiffening the frequency-momentum dispersion of surface plasmons and making it much stronger than that of the underlying narrow-band carriers. Strongly dispersing plasmons pierce through the particle-hole continuum and extend in the forbidden energy band above it. This behavior enables decoupling of plasmons from particle-hole excitations. Such over-the-band plasmons are unable to decay into particle-hole pairs and thus are not subject to Landau damping. As a result, plasmons acquire longer lifetimes as well as an enhanced spatial optical coherence. The optical coherence manifests itself in spatial interference patterns that provide telltale signatures of over-the-band plasmons that are readily accessible in near-field imaging experiments. We further show that the over-the-band plasmon dispersion remains robust in the presence of ordering of the narrow-band carriers. The specific examples of a Wigner crystal and a Mott-Hubbard order, worked out in detail, show that interaction-driven gap opening has no impact on the over-the-band plasmon dispersion. Lastly, we consider the implications of the mechanisms behind the over-the-band behavior for achieving of unidirectional collective modes. We present a new mechanism for plasmon nonreciprocity the magnitude of which is controllable through the strength of electron-electron interactions, which makes it particularly pronounced in the moiré materials.
by Cyprian Lewandowski.
Ph. D.
Ph.D. Massachusetts Institute of Technology, Department of Physics
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Dodgen, Eric Ray. "Spinal Implant with Customized and Non-Linear Stiffness." BYU ScholarsArchive, 2011. https://scholarsarchive.byu.edu/etd/2699.
Повний текст джерелаАнотація:
There is a need for spinal implants that have nonlinear stiffness to provide stabilization if the spine loses stiffness through injury, degeneration, or surgery. There is also a need for spinal implants to be customizable for individual needs, and to be small enough to be unobtrusive once implanted. Past and ongoing work that defines the effects of degeneration on the torque rotation curve of a functional spinal unit (FSU) were used to produce a spinal implant which could meet these requirements. This thesis proposes contact-aided inserts to be used with the FlexSuRe™ spinal implant to create a nonlinear stiffness. Moreover, different inserts can be used to create customized behaviors. An analytical model is introduced for insert design, and the model is verified using a finite element model and tests of physical prototypes both on a tensile tester and cadaveric testing on an in-house spine tester. Testing showed the inserts are capable of creating a non-linear force-deflection curve and it was observed that the device provided increased stiffness to a spinal segment in flexion-extension and lateral-bending. This thesis further proposes that the FlexSuRe™ spinal implant can be reduced in size by joining LET joint geometries in series in a serpentine nature. An optimization procedure was performed on the new geometry and feasible designs were identified. Moreover, due to maintaining LET joint geometry, the contact-aided insert could be implemented in conjunction with this new device geometry.
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Ma, Qinglong. "A study of the dynamic behavior of piecewise nonlinear oscillators with time-varying stiffness." Columbus, Ohio : Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1127847551.
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Hannon, Ashley. "Dynamic strain profile of the ice hockey stick: Comparisons of calibre and shaft stiffness." Thesis, McGill University, 2010. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=95241.
Повний текст джерелаАнотація:
The primary purpose of this study was to develop a method to quantify the dynamic strain profile (DSP) of an ice hockey stick's shaft, and secondly, to use this method to assess the potential influence of player skill calibre and stick shaft properties on DSP during both the slap and wrist shots. Seventeen adult males performed a series of shots using two different stiffness ranked sticks in a laboratory setting on synthetic ice surface. These subjects were subdivided as high and low calibre players. Dependent measures included were: 1) five paired strain gauge responses along the shaft's length recorded at 10 KHz, and 2) kinematics of the puck, stick and trail arm grasping the stick recorded at 300 Hz using a Vicon MX system. 2 x 2 MANOVAs were conducted for each of slap shot and wrist shot trials. The results demonstrated the feasibility of quantifying DSP such that an unambiguous rank order in maximum strain responses was obtained. Further, DSP were sensitive to both factors of player calibre and stick stiffness properties; that is, greater bend induced strains observed by high calibre player and lower stiffness sticks. Two kinematic differences relating to technique were observed: high calibre players showed less elbow flexion during the slap shot and greater wrist flexion during wrist shots. Lastly, with regards to time to maximum strain, high calibre players performed slap shots 3 to 4 times faster than the lower calibre players.L'objectif principal de cette étude était de développer une méthode pour la quantification des différents profils de déformation dynamique de bâtons de hockey et de utiliser qu'est méthode pour examiner l'influence cinématiques du des joueurs de niveau élite et des joueurs de niveau récréatif pour les lancers frappes (SS) et des tirs du poignet (WS). Dix-sept sujets males ont donc effectué en laboratoire une série SS et de WS avec deux bâtons de hockey différent sur une surface de glace synthétique et étaient divisés en deux groupes, un pour le niveau élite et l'autre pour le niveau récréatif. Les mensures dépendantes étaient 1) la déformation du bâton a cinq étroits sur le manche du bâton à l'aide d'un système maison enregistrant à une fréquence de 10 KHz, et 2)la cinématique du bâton, de la rondelle et du membre supérieur le plus bas sur le bâton ont été enregistré à une fréquence de 300 Hz à l'aide d'un système Vicon MX . Deux MANOVA de forme 2x2 ont été effectuées, une pour les lancers frappés ainsi qu'une pour les lancers du poignet. Les résultats ont démontré la faisabilité de la quantification des différents profils de déformation dynamique de bâtons telle que l'ordre de classement sans ambigüité en réponse contrainte maximale a été obtenue. Des différences ont été trouvées pour la déformation aux différents capteurs à travers les niveaux d'habileté ainsi qu'à travers les bâtons. La déformation maximale était différente dépendamment du calibre et du bâton et ce pour les deux types de lancer. De plus, les joueurs de calibre récréatifs ont démontrés un délai significativement plus long entre la déformation maximal et le début du lancer pour les lancers frappés. Des différences cinématiques ont été trouvées au moins flexion du coude entre les calibres pour le niveau élite pour les lancers frappés et plus flexion pour le poignet pour les tirs du poignet pour le n
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Frohling, Robert Desmond. "Deterioration of railway track due to dynamic vehicle loading and spatially varying track stiffness." Thesis, Pretoria : [s.n.], 1997. http://upetd.up.ac.za/thesis/available/etd-01122009-160350.
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Narby, Erik. "Modeling and Estimation of Dynamic Tire Properties." Thesis, Linköping University, Department of Electrical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6153.
Повний текст джерелаАнотація:
Information about dynamic tire properties has always been important for drivers of wheel driven vehicles. With the increasing amount of systems in modern vehicles designed to measure and control the behavior of the vehicle information regarding dynamic tire properties has grown even more important.
In this thesis a number of methods for modeling and estimating dynamic tire properties have been implemented and evaluated. The more general issue of estimating model parameters in linear and non-linear vehicle models is also addressed.
We conclude that the slope of the tire slip curve seems to dependent on the stiffness of the road surface and introduce the term combined stiffness. We also show that it is possible to estimate both longitudinal and lateral combined stiffness using only standard vehicle sensors.
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Ho, Van-Cuong. "Dynamic ruggedizing of printed circuit boards in harsh environmental conditions using a wide-band dynamic absorber." Thesis, Loughborough University, 2003. https://dspace.lboro.ac.uk/2134/34955.
Повний текст джерелаАнотація:
The existing approaches to ruggedizing inherently fragile and sensitive critical components of electronic equipment such as printed circuit boards (PCB) for use in hostile industrial and military environment are either insufficient or quite expensive. This Thesis addresses a novel approach towards ruggedizing commercially-off-the-shelf PCBs using a miniature wide-band dynamic absorber aimed at essential suppressing of the resonant responses of the original structure. The development of an optimisation technique is based on the dynamic properties of the original system, where the mass, stiffness and damping properties of the dynamic absorber are chosen in such a fashion to minimise the level of vibration experienced by the system. The optimisation procedure relies on the analytical solution and computational resources. The results of the proposed single-mode and full-mode approximation are proven experimentally under random vibration. Further study of the dynamic absorber is achieved by considering the system under swept-sine and shock excitations. This approach eventually focuses on the universal performance of the optimal dynamic absorber.
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Lewis, Ray. "High Speed Target C-Band Feed Upgrade for Autotracking High Dynamic Targets." International Foundation for Telemetering, 2012. http://hdl.handle.net/10150/581459.
Повний текст джерелаАнотація:
ITC/USA 2012 Conference Proceedings / The Forty-Eighth Annual International Telemetering Conference and Technical Exhibition / October 22-25, 2012 / Town and Country Resort & Convention Center, San Diego, CaliforniaA new common aperture autotracking C-band feed, specifically designed to accurately track fast moving targets such as the Lance missile, is reviewed. Measured data demonstrates exceptional tracking modulation required for good tracking performance while simultaneously providing excellent data channel performance for high G/T over the entire 4.40-5.25 GHz band. The new patent applied for feed design allows users to maintain existing L/S-band capability with a cost effective field upgrade which adds high performance C-band capability to an existing telemetry tracking system.
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Harrison, Christopher. "The detection of delaminations in vibrating composite beams." Thesis, University of Bath, 2000. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323574.
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Balupari, Raja Shekar. "VALIDATION OF FINITE ELEMENT PROGRAM FOR JOURNAL BEARINGS -- STATIC AND DYNAMIC PROPERTIES." UKnowledge, 2004. http://uknowledge.uky.edu/gradschool_theses/325.
Повний текст джерелаАнотація:
The analysis of bearing systems involves the prediction of their static and dynamic characteristics. The capability to compute the dynamic characteristics for hydrodynamic bearings has been added to Bearing Design System (BRGDS), a finite element program developed by Dr. R.W. Stephenson, and the results obtained were validated. In this software, a standard finite element implementation of the Reynolds equation is used to model the land region of the bearing with pressure degrees of freedom. The assumptions of incompressible flow, constant viscosity, and no fluid inertia terms are made. The pressure solution is integrated to give the bearing load, and the stiffness and damping characteristics were calculated by a perturbation method. The static and dynamic characteristics of 60, 120 and 180 partial bearings were verified and compared for a length to diameter (L/D) ratio of 0.5. A comparison has also been obtained for the 120 bearing with L/D ratios of 0.5, 0.75 and 1.0. A 360-journal bearing was verified for an L/D ratio of 0.5 and also compared to an L/D ratio of 1.0. The results are in good agreement with other verified results. The effect of providing lubricant to the recesses has been shown for a 120 hybrid hydrostatic bearing with a single and double recess.
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Oman, Emmanuel Kabu. "Determination of the dynamic stiffness of a hydrostatic carriage of a high-speed milling machine." [Gainesville, Fla.]: University of Florida, 2002. http://purl.fcla.edu/fcla/etd/UFE0000584.
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Tavares, Rui Afonso. "Influence of the Vertical Support Stiffness on the Dynamic Behavior of High-Speed Railway Bridges." Thesis, KTH, Bro- och stålbyggnad, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-36795.
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Forster, Shauna. "A bilateral electro-hydraulic actuator system to measure dynamic ankle joint stiffness during human stance /." Thesis, McGill University, 2003. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=80012.
Повний текст джерелаАнотація:
The role of the stretch reflex during upright stance remains unclear despite research that has been conducted to date. We have developed a bilateral electro-hydraulic actuator system to measure the dynamic joint stiffness of the human ankle during standing and help understand the role of the stretch reflex in the control of posture. The apparatus consists of two foot pedals that are each connected to an electro-hydraulic rotary actuator. Transducers were incorporated to measure the position and torque of each actuator, the angle of the ankle with respect to the foot plate, and the positions of the knee and hip. The experimental apparatus allows independent perturbations to be applied to each ankle. One subject was studied using the new apparatus and the results showed that reflexes are present during the perturbed standing task.
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Stanton, Kevin V. "Investigation of Parameters Influencing Reverse Fault Rupture Propagation to the Ground Surface." DigitalCommons@CalPoly, 2013. https://digitalcommons.calpoly.edu/theses/1145.
Повний текст джерелаАнотація:
Surface fault rupture poses a serious threat to infrastructure in many seismically active regions, but knowledge about the factors which control the likelihood of surface displacement is limited. Current probabilistic frameworks rely only on fault mechanism and moment magnitude to predict the probability of rupture to the ground surface. However, recent work has shown that there may be other parameters which also deserve consideration. For example, statistical analyses have demonstrated that variation in near surface material stiffness may significantly affect the probability of surface rupture over reverse faults. In addition, numerical investigations indicate that the rupture history of native soil deposits also greatly influences the nature of rupture propagation. Given that evidence exists which suggests multiple variables are at work, this study aimed to improve our understanding of which are most critical for predicting surface fault rupture hazard. We sought to generate physical evidence concerning the impact of near surface soil stiffness, soil type, and rupture history on fault rupture propagation. A 3 meter long by 1 meter wide fault box apparatus was constructed to simulate idealized reverse fault rupture oriented at 45° beneath 60cm of soil. Relatively large dimensions were chosen so that shear wave velocity measurements could be taken directly without interference from the walls of the apparatus. Experiments were conducted on loose sand, dense sand, stiff clay, and soft clay. The same sand was used for both the dense and loose sand experiments and is identified as Monterey #2/16. The clay was a scale model mixture of San Francisco Bay Mud and consisted of kaolinite, bentonite, class C fly ash, and water. Separate batches of clay were mixed with differing final water contents for the stiff and soft clay experiments. In each case, the fault box was filled to 60 cm and rupture was driven to the surface in two phases. The first phase represented an undisturbed native soil deposit with no existing shear band. The second simulated repeat rupture along a pre-existing shear band. The results indicate that increasing material stiffness promotes rupture propagation in both sand and clay. When disturbed soil is re-ruptured, surface rupture occurred much more readily in all materials. Overall, the presence of a pre-existing shear band was shown to have the greatest impact on the likelihood of surface rupture, though both material stiffness and type were also found to have a strong influence as well. The fault box experiments support the findings from previous work as well as shed new light on which parameters are most critical for accurate surface rupture predictions.
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Deymier, Pierre A., Vitthal Gole, Pierre Lucas, Jérôme O. Vasseur, and Keith Runge. "Tailoring phonon band structures with broken symmetry by shaping spatiotemporal modulations of stiffness in a one-dimensional elastic waveguide." AMER PHYSICAL SOC, 2017. http://hdl.handle.net/10150/625507.
Повний текст джерелаАнотація:
Spatiotemporal modulations of the elastic properties of materials can be used to break time and parity symmetry of elastic waves. We show that the form of the elastic band structure depends not only on the spatial and temporal periodicity of a spatiotemporal modulation but also on its shape through its Fourier components. We demonstrate that hybridization gaps open from interactions between the Bloch modes of the periodic medium in absence of the temporal variation of the modulation and the combined sinusoidal components of the Fourier decomposition of the periodic modulation.
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Tufano, Saverio. "Dynamic response of the coupled human body and seat in vertical and fore-and-aft direction." Thesis, Universita' degli Studi di Catania, 2011. http://hdl.handle.net/10761/373.
Повний текст джерелаАнотація:
In many environments vibration is transmitted to a person through a seat. Seats can be designed to reduce the discomfort and the injuries caused by vibration. The efficiency of a seat in reducing vibration depends on the characteristics of the vibration, the characteristics of the seat, and the characteristics of the person sitting on the seat (Griffin, 1990).
This research was designed to investigate several aspects of the transmission of vertical and fore-and-aft vibration through polyurethane foams used in seat construction. The research programme was focused on two experiments. The first experiment was designed: (i) to investigate non-linearities in the seat and the human body in the vertical direction and their contributions to seat transmissibility; (ii) to compare the vertical apparent mass of the human body on rigid and soft seats; (iii) to measure and model the vertical dynamic stiffness of polyurethane foam seat cushions and investigate how the dynamic stiffness depends on vibration magnitude and subject characteristics (i.e. sitting weight, and hip breadth). The second experiment was designed: (i) to investigate the dependence of fore-and-aft seat cushion transmissibility on vibration magnitude, foam stiffness and contact with a backrest; (ii) to compare the fore-and-aft apparent masses of the human body on rigid and soft seats; (iii) to measure and model the dynamic stiffness of polyurethane foam seat cushions in the fore-and-aft direction, compare the fore-and-aft and vertical dynamic stiffness of foam, and investigate how fore-and-aft dynamic stiffness depends on subject sitting weight and hip breadth; (iv) to study the linear and non-linear effects of simultaneous vertical and fore-and-aft vibration and investigate whether single-axis transmissibility and single-axis models can be used to predict seat cushion transmissibility in multi-axis vibration environments.
Fifteen subjects attended the two experiments. In the first experiment, the vertical force and vertical acceleration at the seat base and vertical acceleration at the seat-subject interface were measured during random vertical vibration excitation (0.25 to 25 Hz) at each of five vibration magnitudes (0.25 to 1.6 ms-2 r.m.s.), with four seating conditions (rigid flat seat and three foam cushions). The measurements are reported in terms of the subject apparent mass on the rigid and foam seat surfaces, and the transmissibility and dynamic stiffness of each of the foam cushions. A frequency domain model was used to identify the dynamic parameters of the foams and to investigate their dependence on subject sitting weight and hip breadth.
In the second experiment, the vertical and fore-and-aft forces and accelerations at the seat base and the vertical and fore-and-aft accelerations at the seat-subject interface were measured during random vibration excitation (0.25 to 25 Hz) in fore-and-aft and vertical directions. Using three acceleration magnitudes in each direction (0, 0.25 and 1.0 ms-2 r.m.s.) eight different combinations of vertical and fore-and-aft excitation were investigated with three seating conditions (rigid flat seat and two foam cushions), with and without contact with a rigid vertical backrest.
Both the human body and the foams showed nonlinear softening behaviour, which resulted in nonlinear cushion transmissibility in both the vertical and the fore-and-aft direction. The nonlinearities in vertical cushion transmissibility, expressed in terms of changes in resonance frequencies and moduli, were more dependent on human body nonlinearity than on cushion nonlinearity. The vertical apparent masses of subjects sitting on the rigid seat and on foam cushions were similar, but with an apparent increase in damping when sitting on the foams. Fore-and-aft apparent mass was strongly dependent on the use of the backrest. Fore-and-aft apparent masses on rigid and soft seats had similar shapes. The vertical and fore-and-aft dynamic stiffness of foam was found to be nonlinear with vibration magnitude and showed complex correlations with the characteristics of the human body. Foams were stiffer in the horizontal direction than in the vertical direction. Linear cross-coupling between vertical and fore-and-aft transmissibility was found: a small part of the vertical (or fore-and-aft) vibration at the seat base contributes to fore-and-aft (or vertical) vibration at the subject-seat interface. Nonlinear cross-coupling was found in seat transmissibility and foam dynamic stiffness: the softening of the seat-subject system in one axis is affected by the vibration in the perpendicular direction.
The author believes that this research increased the current state of knowledge of the dynamics of the seated human body and polyurethane foams and so it represents a step forward in the understanding of the mechanisms involved in the vibration isolation provided by seats.
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Caupp, Sarah N. "PMHS Shoulder Stiffness Determined by Lateral and Oblique Impacts." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1397649566.
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Rubio, Pedro, Francisco Fernandez, and Francisco Jimenez. "REAL TIME C BAND LINK BUDGET MODEL CALCULATION." International Foundation for Telemetering, 2016. http://hdl.handle.net/10150/624184.
Повний текст джерелаАнотація:
The purpose of this paper is to show the integration of the transmission gain values of a
telemetry transmission antenna according to its relative position and integrate them in the C band
link budget, in order to obtain an accuracy vision of the link.
Once our C band link budget was fully performed to model our link and ready to work in real
time with several received values (GPS position, roll, pitch and yaw) from the aircraft and other
values from the Ground System (azimuth and elevation of the reception telemetry antenna), it
was necessary to avoid a constant value of the transmitter antenna and estimate its values with
better accuracy depending of the relative beam angles between the transmitter antenna and
receiver antenna. Keeping in mind an aircraft is not a static telecommunication system it was
necessary to have a real time value of the transmission gain.
In this paper, we will show how to perform a real time link budget (C band).
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Schafman, Michelle Ann. "Dynamic Structural Properties of Human Ribs in Frontal Loading." The Ohio State University, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=osu1429018120.
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