Dissertations / Theses on the topic 'Experimental testing'
To see the other types of publications on this topic, follow the link: Experimental testing.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 dissertations / theses for your research on the topic 'Experimental testing.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Mistretta, Joseph P. "Experimental Boss Design and Testing." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/honors/402.
Full textAbstract:
Over the years, gaming has developed rapidly from simple pixel-based experiences to fully blown three-dimensional worlds. As developing technologies improve, so does the complexity and flexibility of what can be created. Encounters, along with all aspects of any gaming experience, have evolved along with the technologies that create them. These intense combat instances, often times referred to as “bosses”, represent a chance for the developer to challenge player skill, cooperation, and coordination. In addition to being major challenges, encounters also allow players to feel a sense of progression as they learn and adapt to mechanics incorporated within an encounter’s design. Eventually these mechanics are mastered, and surmounted to a lasting sense of accomplishment and success. This project details a personal process of encounter design from initial conception to eventual player testing, along with design choices, outside influences, and development methods. These were ultimately utilized in an attempt to create an engaging and successful boss encounter.
2
Nowbutsing, Baboo. "Testing trade theories : an experimental investigation." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.416270.
Full text
3
Lewsey, James Daniel. "Hypothesis testing in unbalanced experimental designs." Thesis, Glasgow Caledonian University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.322213.
Full text
4
Johansson, Erik. "Testing the Explanation Hypothesis using Experimental Methods." Thesis, Linköping University, Department of Computer and Information Science, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-57308.
Full textAbstract:
The Explanation Hypothesis is a psychological hypothesis about how people attribute moral responsibility. The hypothesis makes general claims about everyday thinking of moral responsibility and is also said to have important consequences for related philosophical issues. Since arguments in favor of the hypothesis are largely based on a number of intuitive cases, there is need to investigate whether it is supported by empirical evidence. In this study, the hypothesis was tested by means of quantitative experimental methods. The data were collected by conducting online surveys in which participants were introduced to a number of different scenarios. For each scenario, questions about moral responsibility were asked. Results provide general support for the Explanation Hypothesis and there are therefore more reasons to take its proposed consequences seriously.
5
Isik, Nihat Sinan. "Experimental And Numerical Assessment Of Pressuremeter Testing." Phd thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/2/12607065/index.pdf.
Full textAbstract:
The purposes of this study are to investigate the possible effects of variables like testing depth, length to diameter ratio of the probe, presence of disturbed annulus around the borehole etc. on the derived parameters from the pressuremeter test, and to develop possible alternative methods for the determination of undrained shear strength of cohesive soils, and cohesion and internal friction angle of intermediate geomaterials. For this purpose numerical simulations of pressuremeter test were performed. In
the study, it is also aimed to investigate the effect of rock quality designation (RQD) or some other rock mass parameters such as geological strength index (GSI) and rock mass rating (RMR) and intact rock strength on the deformation modulus determined from the pressuremeter test. To accomplish this task, Dikmen greywackes, weathered andesites and
mudrocks exposed around Ankara - Sincan region were selected for field and laboratory studies. Empirical relationships using GSI, RMR, RQD were developed for the estimation of deformation modulus of greywackes and
mudrocks cropping out around Ankara. Numerical simulations revealed the presence of disturbed annulus around the borehole causes underestimation of deformation modulus and overestimation of undrained shear strength. Test depth has no effect on the deformation modulus and undrained shear
strengththe effect of length to diameter ratio of the probe on the deformation modulus is minor where as it causes overestimations of undrained shear strength. Pore pressure dissipation in low permeability soils around the pressuremeter was studied using numerical simulations. These analyses suggest that for permeabilities lower that 10-10 m/sec there is no pore pressure dissipation around the pressuremeter probe. It was determined that the inverse analysis yielded successful results for the determination of shear strength parameters of intermediate geomaterials.
6
Vaziri, Mohsen. "Screw plate testing : experimental and numerical investigations." Thesis, University of Surrey, 1988. http://epubs.surrey.ac.uk/843439/.
Full textAbstract:
The estimation of the compressibility of normally and overconsolidated granular soils was the main aim of the research. A model screw plate instrument was designed and developed and various plate geometries and plate advancement mechanisms were studied with a view to assessing soil disturbance during installation. Screw plate loading tests were conducted by means of a plate 50 mm in diameter 3 mm thick and 5 mm pitch. All the tests were conducted in a calibration chamber under stress controlled conditions on normally and overconsolidated saturated Leighton Buzzard sand along Ko and isotropic stress paths. Stress path triaxial tests were performed on normally and overconsolidated sand specimens. The stress-strain responses observed from such tests were compared with the pressure-settlement curves obtained from screw plate tests. The CRISP Finite Element Program was utilised to model the embedded plate and the chamber. Stress distributions and induced settlements beneath the plate were studied. Finally the effect of plate rigidity on the distribution of stresses was investigated and the validity of dimensions of the calibration chamber for the purpose of screw plate testing was proven.
7
Krull, Alexander G. (Alexander Gerhard). "Experimental testing of LIGO vibration isolation system." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/40439.
Full textAbstract:
Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaf 29).
The LIGO (Laser Interferometer Gravitational-wave Observatory) project is designed to detect gravitational waves using precision interferometry. The detection from astrophysical sources has the potential to test Einstein's Theory of General Relativity, and additionally open a new window into the universe and its origin. The Initial LIGO detectors are currently operating at a strain sensitivity of 10-21 Hz, or equivalently 1018 m/ [square root of] Hz, at 100 Hz. In order to attain improved sensitivity required for guaranteed detection of astrophysical sources, e.g. coalescing neutron star binaries and black holes, pulsars, and supernovae collapses, improvements of the strain sensitivity must be achieved. Next generation detectors such as Advanced LIGO are under development, which aims to improve the sensitivity by more than a factor of 10 at all frequencies, compared to initial LIGO. This improvement in sensitivity will be achieved in part by improved seismic isolation one component of which is an active vibration isolation platform. Currently, research and development is being conducted at MIT on a prototype of this vibration isolation system. The work described in this thesis focuses on the Internal Seismic Isolation (ISI) system under development for Advanced LIGO.
(cont.) This system consists of a three-stage in-vacuum seismic isolation system which is supported by an external hydraulic actuation stage known as the Hydraulic External Pre-Isolation (HEPI) stages of the active vibration control system. HEPI uses forces generated by hydraulic pressure to cancel low frequency seismic noise, primarily due to forces from ground vibration. The ISI is an actively controlled platform, in which each stage is supported by three maraging steel blade springs. The vibration is sensed in six degrees of freedom and reduced by applying forces through a control feedback loop. In order for the feedback loop to function properly, it is important to know and be able to predict the position of the ISI stages to within a few thousandths of an inch. Since the load being applied to the spring blades is known, the compliance of each spring along with various shim thicknesses will determine the final position of the stages. Although compliance is a material and geometric property, and should remain constant from spring to spring, due to imperfections of the fabrication process and variation in the material properties, small variations in the long and short spring compliance value were detected using a Spring Tester.
(cont.) The blades were designed based on their resonant frequencies and the load which they would be supporting - more specifically, their geometry (length, width, and thickness) were defined such that the load each supported brought them to a 1/3 of their failure stress. For my undergraduate thesis, I determined the compliance of multiple long and short springs was determined using a specially designed apparatus - the "Spring Tester." Ideally, three blade springs of identical compliance should be used to eliminate system imbalance, but to variation during fabrication may be difficult to achieve Using the Spring Tester the mean values for each set of long and short spring linear compliance data were found to be 0.729 +.008 mils/lb and 0.670 ±.027 mils/lb, respectively, while the means for the long and short angular compliance data were 0.078 + .001 mrad/lb and 0.089 ±.003 mrad/lb, respectively.
by Alexander G. Krull.
S.B.
8
SLACK, MICHAEL JAMES. "EXPERIMENTAL TESTING OF NON-EMBEDDED POSITIVE MOMENT CONNECTIONS." University of Cincinnati / OhioLINK, 2002. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1022154276.
Full text
9
Li, Zongze. "Design and Testing of Experimental Langmuir Turbulence Facilities." Scholar Commons, 2019. https://scholarcommons.usf.edu/etd/7845.
Full textAbstract:
Langmuir Circulation is a common phenomenon driven by wind in oceans and lakes and was first studied by Langmuir in 1927. According to various ocean observations, this kind of phenomenon plays an important role in many phenomena such as the aggregation of bubbles, the distribution of plankton as well as the mixing of spilled oil and sediment in the ocean. To study this, an experimental facility has been developed in the lab which creates a small scale version of Langmuir Circulation.
This thesis is about the design and testing of this tank and surrounding aluminum frame, as well as the design and construction of the illumination equipment (the Green Lantern 2.0) needed for Particle Image Velocimetry measurements within the tank. ANSYS will be used to show whether the tank is structurally strong enough to support the fluid. An enhancement is found that prevents a frontward bend of tank wall, which is analyzed by ANSYS to find an optimized construction to minimize tank deformation. Then, the Light-Emitting Diode (LED) and collimating lens selection for the Green Lantern 2.0 will also be shown in this paper. Besides, this thesis also presents preliminary flow measurement data acquired using the illumination equipment (the Green Lantern).
10
Yang, Lintao. "Experimental study of soil anisotropy using hollow cylinder testing." Thesis, University of Nottingham, 2013. http://eprints.nottingham.ac.uk/13641/.
Full textAbstract:
Most sedimentary deposits are inherently anisotropic due to their natural deposition in horizontal layers. This inherent anisotropy highlights the fact that the response of soils to loading is depending on both stress magnitude and its direction. Most of the field problems in geotechnical engineering are three-dimensional, and a soil is more likely to subject an anisotropic stress state (σ1 ≠ σ2 ≠ σ3), together with rotation of the principal axes. It is therefore essential that the soil behaviour under such realistic and general loading conditions is to be well understood, so that engineers can devise appropriate geotechnical design and analysis in practical situations. The Small-Strain Hollow Cylinder Apparatus (SS-HCA), developed by GDS Instruments Ltd. has been used to study drained anisotropic behaviour of sand under generalized stress conditions. In particular, the anisotropic stress-strain-strength characteristics, volume change behaviour, non-coaxiality and combined effects of α and b are studied. Three testing programs composed of two main types of stress paths (e.g. monotonic loading with different inclinations of the major principal stress and cyclic rotation of principal stress axes) were conducted. Inherently anisotropic behaviour of sands is clearly illustrated by deformation response that is strongly dependent on the loading direction in the monotonic shear tests. For a given loading direction, the mechanical response of sands is affected by the material density, the particle properties and the loading history. Non-coincidence of principal directions of stress and strain increment is observed and shear band inclinations in hollow cylindrical specimens follow the theoretical predictions. Results also clearly show the effects of intermediate principal stress on the deformation response of sand. This is seen in variation of stress-strain response and peak friction angle with differing b-values. A significant plastic deformation is induced during rotational shear despite the magnitudes of principal stresses remaining constant. Volumetric strain during rotational shear is mainly contractive and the amount of the volumetric strain increases with the increase in the stress ratio. Most of the contractive volumetric strain occurred during the first 20 cycles and its accumulation rate tended to decrease as the number of cycles increases. When principal stress rotation continues, the sand samples appear to be stabilized and the strain trajectory in the deviatoric plane approaches an ellipse. The test results also demonstrate that the mechanical behaviour of sand under rotational shear is generally non-coaxial, and the stress ratio has a significant effect on the non-coaxiality. The larger the stress ratio, the lower degree of non-coaxiality is induced. It was also observed that parameter b is not a negligible factor for the sand deformation during rotational shear, but has significant impact. The larger the b-value, the more the volumetric strain is accumulated.
11
Jones, Ryan Edward 1974. "Design and testing of experimental free-piston cryogenic expander." Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/80237.
Full text
12
Jayaram, Vinay B. "Experimental Study of Scan Based Transition Fault Testing Techniques." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/31146.
Full textAbstract:
The presence of delay-inducing defects is causing increasing concern in the semiconductor industry today. To test for such delay-inducing defects, scan-based transition fault testing techniques are being implemented. There exist organized techniques to generate test patterns for the transition fault model and the two popular methods being used are Broad-side delay test (Launch-from-capture) and Skewed load delay test (Launch-from-shift). Each method has its own drawbacks and many practical issues are associated with pattern generation and application. Our work focuses on the implementation and comparison of these transition fault testing techniques on multiple industrial ASIC designs. In this thesis, we present results from multiple designs and compare the two techniques with respect to test coverage, pattern volume and pattern generation time. For both methods, we discuss the effects of multiple clock domains, tester hardware considerations, false and multi-cycle paths and the implications of using a low cost tester. We then consider the implications of pattern volume on testing both stuck-at and transition faults and the effects of using transition fault patterns to test stuck-at faults. Finally, we present results from our analysis on switching activity of nets in the design, while executing transition fault patterns.Master of Science
13
Mudiya, Pavan Kumar. "Experimental testing and performance analysis of "room air cleaners"." Cleveland, Ohio : Cleveland State University, 2008. http://rave.ohiolink.edu/etdc/view?acc_num=csu1236214686.
Full textAbstract:
Thesis (M.S.)--Cleveland State University, 2008.Abstract. Title from PDF t.p. (viewed on Apr. 30, 2009). Includes bibliographical references (p. 100-101). Available online via the OhioLINK ETD Center. Also available in print.
14
Rivers, Roger Troy. "Experimental Testing of CFRP Splays Bonded to Uniaxial Fabric." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/321612.
Full textAbstract:
The use of fiber reinforced polymers (FRP's) for structural repair or retrofit has increased significantly in the last decade, with adoption for civil infrastructure occurring only in the last 20 years. These products are most often used to increase the capacity of damaged or deteriorated structures. Much research has been performed in the arena of testing of various FRP's bonded to both concrete and masonry substrates, the majority of which focusing on three areas; flexural strengthening, in-plane shear strengthening, and mechanical anchoring. Anchorage is commonly the limiting factor in the application of FRP's, due to the inability of the edge of the polymer matrix to reliably extend beyond a point of zero-interfacial stress. Where interfacial stresses exist and the FRP is terminated localized disbondment often occurs, these localized failures then propagate across the entire bond of the structural system. Various mechanical termination details have been tested to mitigate the potential failure modes near the ends of the fabric. There, however, has been very limited research performed on the behavior of dowels which are installed parallel to the FRP fabric and splayed onto the FRP fabric matrix. In this research the mechanical properties of carbon fiber reinforced polymer (CFRP) dowels with a parallel orientation to uniaxial carbon fabric are experimentally tested to determine the tensile capacity of "dowel to splay" CFRP connections and to discover any dominant failure modes.
15
Machado, Rafael Ignacio. "Experimental investigation of steel tubed reinforced concrete columns." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/19457.
Full text
16
Gardner, Kevin Alexander. "Experimental Techniques for Shear Testing of Thin Sheet Metals and Compression Testing at Intermediate Strain Rates." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1366199322.
Full text
17
Agarwal, Anil K. (Anil Kumar). "An application of sequential experimental design in catalyst kinetic studies." Phd thesis, Department of Chemical Engineering, 1994. http://hdl.handle.net/2123/10235.
Full text
18
Lam, Wai-yin, and 林慧賢. "Experimental study on embedded steel plate composite coupling beams." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2003. http://hub.hku.hk/bib/B26643352.
Full text
19
Astrup, Oda Skog. "Experimental Investigations of Ice Rubble: Shear Box and Pile Testing." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for bygg, anlegg og transport, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-18599.
Full textAbstract:
The largest part of an ice ridge consists of unconsolidated ice rubble, whose material properties decide the load from ridges on ships and structures. Material resistance is attributed to the initial freeze-bonds and the friction and interlocking between blocks. The objective of the thesis was to investigate rubble behaviour by two tests: shear box test at NTNU and pile test at HSVA. The shear box test was aimed at investigating freeze-bond mechanisms in rubble. The pile test was aimed at suggesting values for rubble properties for a model scale experiment.The shear box had dimensions 600 mm x 400 mm x 40 mm, and was filled with ice blocks of 60 mm x 22 mm x 40 mm simulating rubble. Confinement was added, the box was submerged for 10 minutes, and tested in a rig by forcing the rubble to fail in shear. Force vs. displacement was measured. Different types of saline ice and submerging water temperatures were used. Pile testing consisted of making an elongated pyramid-shaped pile, baseline 600 mm, of rubble collected from the ice tank at HSVA. The pile was tilted and geometry was measured before and after failure happened in the pile.Main results from the shear box tests were the observation of a first phase deformation of rubble, that displayed a near linear force-displacement relation and a first peak shear stress. Magnitude of first peaks was measured in the range 8.9 kPa to 59.7 kPa, and depended on submersion water temperature, salinity of ice, how blocks were cut in respect to crystal structure in the ice sheet and confining pressure. Pile tests had repose angles ranging from 36.0° to 47.3°, and cohesion for an assumed angle of friction of 30° was in the range of 172 Pa to 342 Pa. First phase shear stress was compared to shear strength of single freeze-bond tests of the same ice, and direct relations were found. The magnitude of first peak shear stress in tests varied most with ice salinity and crystal structure. The measured repose angles for pile tests give an upper limit for internal angles of friction, and values seemed reasonable. The ice was warm, and this may the reason for the low cohesions.
20
Eamcharoenying, Pooh. "Hybrid numerical-experimental testing of active and semi-active suspensions." Thesis, University of Bath, 2015. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.665447.
Full textAbstract:
This thesis details the development of an experimental test rig to measure the performance of semi-active and active vehicle suspensions. Due to the variety of suspension components, configurations and vehicle types that might adopt active suspensions a hybrid numerical-experimental test rig were developed using simulation and a range of mechanical and microprocessor hardware. Using Model-in-the-Loop and Hardware-in-the-Loop systems representing the suspension allows for flexibility in the testing of various suspension components. Similarly a model-in-the-loop system representing the vehicle structure was developed to investigate flexible systems such as those found in an aircraft. This allows the dynamic interaction between the structural flexible vibration modes and the suspension to be established. Actuator tracking errors are crucial to the accuracy and stability of model-in-the-loop systems. Friction was shown to be a major source of tracking error for the suspension model-in-the-loop actuator and this led to the development of a novel force controlled friction compensator which resulted in a 37% improvement of the test rig accuracy and a reduction of peak force error by approximately 50%. Another source of tracking error which directly effects system stability is system delays caused by actuator, sensor, computational and filter lags. The effect of these delays upon the accuracy and stability of the test rig is analysed and discussed. Finally, passive, semi-active and active skyhook quarter car experiments were conducted and verified using the hybrid test rig. The results show that characteristics of passive, semi-active and active suspensions, and their dynamic interaction with a flexible vehicle structure can be successfully replicated using the test rig.
21
Shahid, Sharlin, and Widaad Gukhool. "Experimental Testing and MaterialModeling of Anisotropy in InjectionMoulded Polymer Materials." Thesis, Blekinge Tekniska Högskola, Institutionen för maskinteknik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-19720.
Full textAbstract:
Experimental characterization of the mechanical properties in a thin injection moulded Low-Density Polyethylene (LDPE) plate is per- formed in this work. Anisotropy in LDPE at different material orientations is measured from the Digital Image Correlation (DIC) observation of the specimens during uniaxial tensile test. From the test response and observation from DIC, the studied material is found to be significantly anisotropic. Finite Element simulation (FE-simulation) of in-plane anisotropy of material is carried in AbaqusTM R2020 using available models like Hill48 and Barlat2004. When necessary the simulation plastic potentials for these models are optimized against experimental yield stress ratio (R) and anisotropic ratio (r). To express the nonlinear mechanical behavior, a suitable hardening extrapolation model, namely Swift/Hockett-Sherby is selected from several extrapolation models based on experimental data. To validate the experimental methods, simulation methods and material characterization process, finite element simulation results such as force displacement, strain distribution and different anisotropic related properties are compared with the experimental data. Finally, advantages and disadvantages of different simulation models are discussed.
22
Vaidya, Rohit Subhash. "Experimental testing of a computer aided heat treatment planning system." Link to electronic thesis, 2003. http://www.wpi.edu/Pubs/ETD/Available/etd-0827103-111212.
Full text
23
INFUSO, ANDREA. "Silicon photovoltaics: experimental testing and modelling of fracture across scales." Doctoral thesis, Politecnico di Torino, 2016. http://hdl.handle.net/11583/2651682.
Full textAbstract:
The study of the properties of materials can be addressed through a multi-scale approach, in order to have the possibility to grasp at each of the levels of analysis the peculiar aspects. Tracing a path inside the state-of-the-art in the available bibliography, historically in the field of mechanics s are found in which the material is studied through nonlocal theories based on continuous or discrete local approaches. More recently, with the advent of great computatio- nal power computers, analytical methodologies based on theories also very complex deriving from the field of chemistry and physics have been developed, capable to discretize at the ato- mic scale the material and study its behavior by applying energy approaches. Starting from the analysis of some of these theories at the nano- and micro-scales, it is possible to investi- gate the separation mechanisms at the molecular level, which may be considered as cracking processes within the material according to the adopted scale of analysis. The application of theories of this kind to large portions of material, in which there are up to some millions of particles involved is reasonably not an applicable solution, since it would require a huge effort in terms of computation time. To work around this problem and find a method suitable for the study of cracking mechanisms, a mixed method (MDFEM) was byconjugating pure molecu- lar dynamics (MD) and the finite element method (FEM), in which the material is discretized by means of one-dimensional elements whose mechanical characteristics are derived from MD. This approach is based on the application of a nonlocal theory in which the contribution of a portion of material placed within a certain distance from the point of fracture is taken into account by means of a parameter of non-locality. Moreover, the study of the evolution of cracking is addressed at the meso-scale by the application of a cohesive non-linear model.
Towards the analysis of the macroscale, the theories put forward so far have been ap- plied to the study of phenomena of breakage inside Silicon cells embedded into rigid or semi-flexible photovoltaic modules. By performing various laboratory tests, useful for the characterization of the material and for understating the evolution of cracking process due to multiple causes, a study on the main issues that may compromise the durability and mainte- nance of the expected service levels of photovoltaic panels has been conducted. Experimen- tally results have been interpreted by using appropriate macro-scopic continuum models. The research carried out had the purpose to provide an introduction to a correct design of these systems of energy production in order to increase their durability and resistance to cracking.
24
Xia, Qingxi. "Numerical and experimental analysis of the dynamic behavior of concrete and mortar." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/18981.
Full text
25
BERTOLINI, Cristiano. "Evaluation of GUI testing techniques for system crashing: from real to model-based controlled experiments." Universidade Federal de Pernambuco, 2010. https://repositorio.ufpe.br/handle/123456789/2076.
Full textAbstract:
Made available in DSpace on 2014-06-12T15:54:24Z (GMT). No. of bitstreams: 2
arquivo7096_1.pdf: 2072025 bytes, checksum: ca8b71b9cfdeb09118a7c281cafe2872 (MD5)
license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5)
Previous issue date: 2010Conselho Nacional de Desenvolvimento Científico e Tecnológico
Aplicações para celular estão se tornando cada vez mais complexas, bem como testá-las. Teste de interfaces gráficas (GUI) é uma tendência atual e se faz, em geral, através da simulação de interações do usuário. Várias técnicas são propostas, no qual, eficiência (custo de execução) e eficácia (possibilidade de encontrar bugs) são os aspectosmais cruciais desejados pela industria. No entanto, avaliações mais sistemáticas são necessárias para identificar quais técnicas melhoram a eficiência e eficácia de tais aplicações. Esta tese apresenta uma avaliação experimental de duas técnicas de testes de GUI, denominadas de DH e BxT, que são usadas para testar aplicações de celulares com um histórico de erros reais. Estas técnicas são executadas por um longo período de tempo (timeout de 40h, por exemplo) tentando identificar as situações críticas que levam o sistema a uma situação inesperada, onde o sistema pode não continuar sua execução normal. Essa situação é chamada de estado de crash. A técnicaDHjá existia e é utilizadapela industriade software, propomos outra chamada de BxT. Em uma avaliação preliminar, comparamos eficácia e eficiência entre DH e BxT através de uma análise descritiva. Demonstramos que uma exploração sistemática, realizada pela BxT, é uma abordagem mais interessante para detectar falhas em aplicativos de celulares. Com base nos resultados preliminares, planejamos e executamos um experimento controlado para obter evidência estatística sobre sua eficiência e eficácia. Como ambas as técnicas são limitadas por um timeout de 40h, o experimento controlado apresenta resultados parciais e, portanto, realizamos uma investigação mais aprofundada através da análise de sobrevivência. Tal análise permite encontrar a probabilidade de crash de uma aplicação usando tanto DH quanto BxT. Como experimentos controlados são onerosos, propomos uma estratégia baseada em experimentos computacionais utilizando a linguagem PRISM e seu verificador de modelos para poder comparar técnicas de teste de GUI, em geral, e DH e BxT em particular. No entanto, os resultados para DH e BxT tem uma limitação: a precisão do modelo não é estatisticamente comprovada. Assim, propomos uma estratégia que consiste em utilizar os resultados anteriores da análise de sobrevivência para calibrar nossos modelos. Finalmente, utilizamos esta estratégia, já com os modelos calibrados, para avaliar uma nova técnica de teste de GUI chamada Hybrid-BxT (ou simplesmente H-BxT), que é uma combinação de DH e BxT
26
Okoli, Okenwa Obinna Ifeanyichukwu-Izejiora. "Experimental determination of transient dynamic response of fibre reinforced polymer composites." Thesis, University of Warwick, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.273471.
Full text
27
Gonzalez, Alvaro Andres. "An experimental study of the deformational and performance characteristics of foamed bitumen stabilised pavements." Thesis, University of Canterbury. Civil and Natural Resources Engineering, 2009. http://hdl.handle.net/10092/3285.
Full textAbstract:
The research presented in this thesis studies the effects of foamed bitumen on the deformational behaviour and performance of pavement materials. The research was conducted in the laboratory and the field, using specific New Zealand materials. The aggregate used is a blend of a coarse aggregate imported from the Auckland region with a crushed dust from the Canterbury region. The bitumen selected for the study is an 80/100 bitumen grade, and the active filler was a Portland Cement, both commonly used for foamed bitumen stabilization in New Zealand.
In the laboratory, samples of mixes with different foamed bitumen content were tested under various loading and stress conditions to investigate the effects of foamed bitumen on the deformational behaviour of the mix. The tests performed were: Indirect Tensile Strength (ITS), Indirect Tensile Resilient Modulus (ITM), Repeat Load Triaxial compression (RLT) and Monotonic Load Triaxial compression (MLT). Preliminary ITS and RLT tests conducted on mixes with 1% and 0% cement, at different foamed bitumen contents, indicated that mixes without cement performed poorly compared to the mixes with 1% cement. Therefore, the rest of the laboratory study was on mixes with 1% cement.
ITS tests were conducted on 150 mm specimens prepared with 0% 1%, 2%, 3% and 4% bitumen content, with a common 1% cement. Results indicated that foamed bitumen increases the ITS values of the mix, up to an estimated optimum of 2.8% bitumen content. Similar trends were obtained with ITM tests, in which a diametrical load pulse was applied on 150 mm specimens, showing an estimated resilient modulus peak near to 2.8% bitumen content.
RLT specimens were prepared at 0%, 2% and 4% bitumen content, at two compaction efforts, creating specimens at low and high bulk density. Permanent deformation RLT tests involved the application of seven stages of 50,000 load cycles each (4 Hz), with increasing deviator stress (from 75 kPa in the first stage, up to 525 kPa in the seventh stage) and at constant confining pressure of 50 kPa. Results of RLT permanent deformation tests indicated that the increase in the foamed bitumen content resulted in an increase in the permanent deformation of the material.
MLT tests were conducted on specimens at 0%, 2% and 4% bitumen contents, at two compaction efforts, creating specimens of low and high bulk density, at confining pressures ranging from 50 kPa to 300 kPa, with a deformation rate of 2.1% per minute. Results indicated that the effect of foamed bitumen was a reduction of the peak vertical stress, or a reduction in the peak strength.
The peak stresses obtained in MLT tests were plotted in stress diagrams, and the failure was approximated as linear function of the confining stress. The fundamental shear parameters (angle of internal friction and apparent cohesion) were estimated, and results indicated that foamed bitumen has no apparent effect in cohesion but does reduce the angle of internal friction. The reduction of the angle of internal friction explains the general trends observed in the laboratory, that on one hand the compressive strength decreases with increasing bitumen content, but on the other hand, the tensile strength increases up to an optimum.
A full-scale experiment was carried out using an accelerated testing of foamed bitumen pavements at the Canterbury Accelerated Pavement Testing Indoor Facility (CAPTIF). In the full-scale experiments, the same materials that were tested in the laboratory (aggregates, bitumen, cement) were used to construct six different pavement sections, each with different contents of bitumen and cement. Three were constructed using foamed bitumen contents of 1.2%, 1.4% and 2.8% respectively, plus a common active filler content of 1.0% cement. Two more pavements were constructed adding cement only (1.0%), and foamed bitumen only (2.2%). In addition, one control section with the untreated unbound material was tested. Strains were collected using a 3D Emu soil strain system installed in each pavement section. The curing time between construction and pavement loading was approximately three months. The pavement response, such as surface deformation (rutting), surface deflections and strains were periodically recorded during the execution of the test. The strains were collected at different depths by using an array of Emu strain gauges. Deflections were recorded using both a Falling Weight Deflectometer (FWD) and CAPTIF Beam deflectometer, which is a modified Benkelmann beam. A total number of approximately 5.6 million equivalent standard axles were applied on the pavement sections.
The rutting measured in the sections stabilised with foamed bitumen and cement was the lowest, showing that the addition of foamed bitumen significantly improved the performance of materials with 1% cement. The sections stabilised with cement only, foamed bitumen only, and the control untreated section showed large amounts of rutting and heaving by the end of the test.
Deflection measurements showed that the effect of foamed bitumen content is a reduction of pavement deflections, with the lowest deflection measured in the section stabilised with 2.8% bitumen and 1% cement. The elastic pavement strains showed that foamed bitumen reduced the tensile strains in the basecourse but did not have a significant effect on vertical compressive strains.
During the construction of pavements, material samples were taken for ITS and RLT testing. Results indicated that the highest ITS was measured in the section with 2.8% foamed bitumen content and 1% cement, and the ITS in the section without cement and foamed bitumen only was about 4-5 times lower than the ITS measured in specimens with cement. RLT specimens without cement performed poorly in comparison with the specimens with 1% cement. The specimens with 1% cement showed higher permanent deformation with increase in the foamed bitumen content, supporting the results from the previous laboratory study.
To interpret and relate the results observed in the laboratory and the field, stress path analysis was used, in which the stress ratio of the foamed bitumen layers was calculated at different depths. The analysis showed that foamed bitumen content decreases the maximum stress ratio, hence reducing the proximity to failure and relative damage of the layer. Three-dimensional and two-dimensional finite element modelling of the CAPTIF pavements, were used to further investigate the stress and strain fields induced by the loading and to explain the pavement performance observed in the full-scale experiment.
28
Chen, Hwei-yen. "Experimental Evolution of Life-history : Testing the Evolutionary Theories of Ageing." Doctoral thesis, Uppsala universitet, Zooekologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-231948.
Full textAbstract:
Ageing reduces fitness, but how ageing evolves is still unclear. Evolutionary theory of ageing hinges on the fundamental principal that the force of natural selection declines with age. This principle has yielded two important predictions: 1) the evolution of faster ageing in populations under high rate of extrinsic mortality; and 2) the evolution of faster ageing in a sex that experiences higher rates of extrinsic mortality. However, an emerging new theory argues that when the extrinsic mortality is not random but instead selects on traits showing positive genetic correlation with lifespan, increased mortality should lead to the evolution of increased lifespan. Such condition-dependent mortality is also expected to increase the robustness in the population, resulting in increased deceleration of mortality in late-life. Similarly, high sex-specific mortality can result in increased sex-specific selection on traits that have positive pleiotropic effects on lifespan in the affected sex. This thesis is based on two experimental evolution studies in Caenorhabditis remanei. The first experiment was designed to disentangle the effects of the rate (high or low) and the source (random or condition-dependent) of mortality on the evolution of lifespan and ageing. Reduced lifespan evolved under high rate of random mortality, whereas high condition-dependent mortality, imposed by heat-shock, led to the evolution of increased lifespan (Paper I). However, while female reproduction increased under condition-dependent mortality, male reproduction suffered, suggesting a role for sexual antagonism in maintaining genetic variation for fitness (Paper II). Besides, long lifespan and high fecundity evolved at a cost of slow juvenile growth rate in females (Paper III). Moreover, high condition-dependent mortality led to the evolution of lower rate of intrinsic mortality in late-life (Paper IV). The second experiment showed that evolution of sexual dimorphism in lifespan is driven by the factors that cause sex-specific mortality and cannot be predicted from differences in mortality rate alone. Specifically, high condition-dependent mortality renders males less prone to ageing than females despite higher rates of male mortality (Paper V). The strength of this thesis is the reconfirmation of the earlier findings combined with support for the new theory. Rather than further complicating the matter, the inclusion of the new ideas should help explain some empirical results that are inconsistent with the classic theory, as well as provide a more comprehensive picture of ageing evolution.
29
Carlin, Daniel Edward. "Experimental and numerical characterization of damage in FRP beams." Thesis, Georgia Institute of Technology, 1994. http://hdl.handle.net/1853/21465.
Full text
30
Goudie, K. "Experimental study of the gross deformation of tubular beams." Thesis, University of Manchester, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380143.
Full text
31
Skjølberg, Ole Georg, and Anders Hansson. "Hybrid Concrete Structures : Experimental Testing and Numerical Simulation of Structural Elements." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for konstruksjonsteknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12455.
Full textAbstract:
The Composite Sandwich Slab (CSS) studied in this report is a hybrid concrete structure with different concrete types in zones of high versus low stresses. The CSS is a combination of a precast concrete formwork and in-situ concrete, where a structural top layer is supposed to be cast at the construction site. It is intended that the precast concrete formwork would be lifted directly into position before the structural top layer is cast. The precast concrete formwork consist of a relatively thin bottom layer in reinforced normal concrete with a thicker steel fiber reinforced lightweight concrete layer above. The CSS concept is supposed to be an alternative to today’s existing slab solutions in buildings and harbor structures. The CSS concept is lighter than a traditional concrete slab, but with maintained load carrying capacity. For a typical 250mm thick slab the weight reduction would be up to 35% compared to a traditional concrete slab. The precast CSS elements are also stiffer than today’s existing precast products, which means that the number of temporary supports needed during the construction phase can be reduced or eliminated. This reduction would lead to saved time, space and money at the construction site. The lightweight concrete used in the precast formwork has an approximate density of 900kg/m2 – 1150kg/m2 with a compressive strength in the range of 15-20 MPa. The lightweight concrete is relatively new product and is therefore first studied through laboratory tests with respect to compressive strength, tensile strength and shear capacity. Since the material properties for the lightweight concrete is going to be used in numerical analyses, the first laboratory tests are analyzed numerically in order to verify that agreement can be obtained and that the material models used are valid for this specific concrete. The results indicate good agreement. A concept CSS beam is then designed, tested and analyzed both by hand and numerically in order to state the CSS capacity as a slab construction. The concept CSS beam is both tested and analyzed with and without the structural top layer, i.e. as a finished product and during construction phase respectively. The laboratory tests indicate competitive capacities for both types. Hand calculations and numerical analysis performed after the test had good correlation with respect to the capacities and displacements obtained in the laboratory when testing the concept beam. The numerical analyses are therefore valid and can be used in further analyses of the CSS concept. The numerical model used in the post analysis of the CSS has been exposed to realistic loading. Both analysis of the precast part of the CSS during construction phase and analysis of the CSS with top layer and loading according to NS 3491-1 has been performed. Material and load factors have also been taken into account. The results from these analyses are promising with respect to the CSS general capacity. Results show that it is possible to use the precast formwork without temporary supports during the construction phase for a typical concrete slab with a span of 6m.
32
Clark, Cindy, and R. Warren Miller. "Experimental research and empirical testing of distributed Group Decision Support Systems." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/42109.
Full textAbstract:
Past research in the area of Group Decision Support Systems (GDSS) has attempted to ascertain its future potential in the business world. This thesis extends the GDSS research to the area of distributed Group Decision Support Systems (DGDSS) . An experiment was performed where groups of three and four persons were tested in different group decision making settings, a traditional decision room and a DGDSS. An experimental prototype DGDSS program, developed at Claremont University, Claremont, CA, was evaluated during the experiment. The experiment pointed out several program advantages and disadvantages during the evaluation. The study determined that use of the DGDSS resulted in generation of larger numbers of criteria and alternatives and greater decision satisfaction. DGDSS supported groups experienced: less commitment to the final decision, less satisfaction with the decision process, and less satsifaction with communication.
33
Al-Huthaili, Salim Saif. "Theoretical, experimental and field testing of ground source heat pump systems." Thesis, University of Nottingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410189.
Full text
34
Chen, Xiaoran. "Computational and Experimental Approach for Non-destructive Testing by Laser Shearography." Digital WPI, 2014. https://digitalcommons.wpi.edu/etd-theses/928.
Full textAbstract:
"Non-destructive testing (NDT) is critical to many precision industries because it can provide important information about the structural health of critical components and systems. In addition, NDT can also identify situations that could potentially lead to critical failures. Specifically, NDT by optical methods have become popular because of their non-contact and non-invasive nature. Shearography is a high-resolution optical NDT method for identification and characterization of structural defects in components and has gained wide acceptance over the last decade. Traditional workflow of NDT by shearography has been determined to be inefficient, due to the requirements of having experienced operators that must determine the most suitable loading methods to identify defects in samples under testing as well as to determine the best system arrangement for obtaining the maximum measuring sensitivity. To reduce the number of experiments that are required and to allow inspectors to perform NDT by laser shearography in a more efficient way, it is necessary to optimize the experimental workflow. The goal of the optimization would be an appropriate selection of all experimental variables including loading methods, boundary conditions, and system¡¯s sensitivities, in order to avoid repeating experiments several times in the processes of components characterization and health monitoring. To achieve this goal, a hybrid approach using shearographic fringe prediction with Finite Element Analysis (FEA) has been developed. In the FEA simulations, different loading conditions are applied to samples with defects, and in turn, the shearographic fringes are predicted. Fringe patterns corresponding to specific loading conditions that are capable of detecting defects are chosen and experimental tests are performed using those loading conditions. As a result, using this approach, inspectors could try different combinations of loading methods, and system¡¯s sensitivities to investigate and select appropriate experimental parameters to improve defect detection capabilities of the system by using low-cost computer simulations instead of lengthy and expensive experiments. In addition, to improve the identification of defects on the sample, camera calibration and image registration algorithms are used to project the detected defects on the sample itself to locate and visualize the position of defects during shearographic investigations. This hybrid approach is illustrated by performing NDT of a plate made of acrylic that has a partial hole at the center. Fringe prediction with finite element analysis are used to characterize the optimized experimental procedures and in turn, corresponding measurements are performed. A multimedia projector is employed to project the defects on the surface of the plate in order to visualize the location of the partial hole (defect). Furthermore, shearographic system is used for other applications including NDT of a composites plate and of a thin latex membrane. The procedures shows the effectiveness of the approach to perform NDT with shearography methods. "
35
Clay, Arthur C. (Arthur Chisholm) 1971. "Development and experimental characterizaton of ultrasonic phased arrays for nondestructive testing." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/10032.
Full text
36
Kreiss, Amberg Mårten. "Thin metal patch to FRP propeller: Experimental testing of bonding systems." Thesis, KTH, Lättkonstruktioner, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-185309.
Full textAbstract:
To enable the use of carbon fibre reinforced polymer (CFRP) propellers for merchant vessels, the problem of cavitation must be solved. The matrix of the FRP is generally brittle and more sensitive to cavitation erosion than the more conventional metal propeller blades. Nakashima Propeller Co. wants to solve this problem by attaching a metal patch adhesively in the high-risk areas of the blade. The bonding of FRP and metal is a classic problem when manufacturing hybrid components, and even more difficult when the bond is subject to fatigue loads, in a marine environment. The thin metal plate makes determining the crack resistance from the energy release rate difficult and a novel approach is necessary.This report focuses on outlining the problem and establishes an experimental method for conducting the initial investigations of the robustness of an adhesive bond for this application. Four different adhesives were tested in quasi-static mode I loading with constant cross-head velocity: Denatite 2204, co-curing, Newport 102 and Plexus AO420. All adhesives were epoxy based except for the Plexus. The co-cured system used resin Epolam 5015, the same was used for manufacturing the FRP in the other specimen. Instead of computing the energy release rate, the crack tip angles were compared between the different adhesive systems. These measurements are only internally comparable. Based on the results from the quasi-static loading, the Denatite and the Plexus were brought into a smaller fatigue testing series. The two others were deemed as too weak to be of interest.The experiments showed that the methacrylate based Plexus AO420 had a significantly higher strength, in the quasi-static loading it had a maximum recorded load almost ten times as high as the denatite. The fatigue test was inconclusive, although no drastic or unexpected behaviour was recorded. It was noted during the process (unsurprisingly) that the manufacturing process and the skill of the worker is very much affecting the bond strength, sometimes even more than the material properties and the surface treatments applied.The experimental method, including the measurements of the crack tip angle could be concluded as a simple but effective method to determine the basic adhesive strength and general characteristics of the different types. The second series of fatigue testing can be performed to see general fatigue behaviour for the adhesives, but as the actual load case on the propeller is unknown it can be difficult to directly relate the fatigue behaviour in the test to the real world. Both test series can be used to determine general behaviour, but due to the complexity of the geometry, deformation modes and loads on the real propeller, it is suggested to perform final testing on a live propeller, rather than trying to draw to large conclusions from isolated experiments.F¨or att m¨ojligg¨ora anv¨andning av kompositpropellrar av kolfiberf¨orst¨arkt polymer (CFRP) f¨or handelsfartyg, m˚aste problemet med kavitation l¨osas. Matrisen i FRP ¨ar i regel v¨aldigt spr¨od och mer k¨anslig f¨or kavitation-serosion ¨an de mera konventionella metallpropellerbladen. Tillverkningsf¨oretaget Nakashima Propeller Co. vill l¨osa detta problem genom att f¨asta en metallplatta fastlimmad i h¨ogriskomr˚adena p˚a bladet. F¨orbandet av FRP och metall ¨ar ett klassiskt problem vid tillverkning av hybridkomponenter, och ¨annu sv˚arare n¨ar det ¨ar utsatt f¨or utmattningsbelastningar, i en marin milj¨o. D˚a det ¨ar en relativt tunn metallplatta ¨ar det sv˚art att best¨amma sprickmots˚andet fr˚an energidissipationshastigheten G och ett nytt tillv¨agag˚angss¨att ¨ar n¨odv¨andigt.Denna rapport fokuserar p˚a beskriver problemet och etablerar en experimentell metod f¨or att genomf¨ora inledande unders¨okningar av robusthet en limbindning f¨or denna applikation. Fyra olika lim testades i kvasi-statiskt lastning av mod I med konstant cross head-hastighet: Denatite 2204, samh¨ardning, Newport 102 och Plexus AO420. Alla lim var epoxibaserade f¨orutom Plexus. Det samh¨ardade systemet anv¨ande samma matris som vid tillverkningen av FRP i de andra provbitarna: Epolam 5015. I st¨allet f¨or att ber¨akna energidissipationshastigheten j¨amf¨ordes vinklarna vid sprickspetsen mellan de olika limsystemen. Dessa m¨atningar var bara internt j¨amf¨orbaa inom testserien. Baserat p˚a resultaten fr˚an den kvasi-statiska belastningen togs enbart Denatite och Plexus vidare till en mindre serie utmattningsprover. De tv˚a andra ans˚ags alltf¨or svaga f¨or att vara av intresse.F¨ors¨oken visade att metakrylatbaserade Plexus AO420 hade en betydligt h¨ogre styrka, i kvasi-statisk belast-ning hade det den h¨ogsta uppm¨atta lasten, n¨astan tio g˚anger s˚a h¨og som Denatite 2204. Det gick inte attd ra npgra direkta slutsatser fr˚an utmattningstestet, men inget drastiskt eller ov¨antat beteende registrerades. Det noterades under processen (inte f¨orv˚anande) att tillverkningsprocessen och skickligheten hos arbetaren ¨ar myckket viktig och p˚averkar f¨orbandsstyrkan i h¨og grad, ibland ¨annu mer ¨an materialegenskaper och de ytbehandlingar som till¨ampas.Slutsatsen att den experimentella metoden, inklusive m¨atningar av sprickspetsvinkeln kan beskrivas som en enkel men effektiv metod f¨or att j¨amf¨ora och dra slutsatser om vidh¨aftningsstyrkan och allm¨anna egenskaper hos de olika limtyperna kan dras. Den andra serien av utmattningsprovning kan utf¨oras f¨or att se allm¨ant utmattningsbeteendet f¨or limmen, men d˚a det faktiska lastfallet p˚a propellern ¨ar ok¨ant kan det vara sv˚art att direkt relatera utmattningsbeteende i testet till den verkliga v¨arlden. B˚ada provserierna kan anv¨andas f¨or att best¨amma allm¨anna beteenden, men p˚a grund av komplexiteten av geometri, deformationstillst˚and och belastningar p˚a den verkliga propellern f¨oresl˚as det att utf¨ora slutliga tester p˚a en riktig propeller, snarare ¨an att f¨ors¨oka dra stora slutsatser fr˚an isolerade experiment.
37
Mathews, Vayalat Thomas. "Tire Contact Patch Characterization through Finite Element Modeling and Experimental Testing." Thesis, Virginia Tech, 2016. http://hdl.handle.net/10919/82708.
Full textAbstract:
The objective of this research is to provide an in-depth analysis of the contact patch behavior of a specific passenger car tire. A Michelin P205/60R15 tire was used for this study. Understanding the way the tire interacts with the road at various loads, inflation pressures and driving conditions is essential to optimizing tire and vehicle performance. The footprint shape and stress distribution pattern are very important factors that go into assessing the tire's rate of wear, the vehicle's fuel economy and has a major effect on the vehicle stability and control, especially under severe maneuvers.
In order to study the contact patch phenomena and analyze these stresses more closely, a finite element (FE) tire model which includes detailed tread pattern geometry has been developed, using a novel reverse engineering process. In order to validate this model, an experimental process has been developed to obtain the footprint shape and contact pressure distribution. The differences between the experimental and the simulation results are discussed and compared. The validated finite element model is then used for predicting the 3D stress distribution fields at the contact patch. The predictive capabilities of the finite element tire model are also explored in order to predict the handling characteristics of the test tire under different maneuvers such as pure cornering and pure braking.Master of Science
38
Cox, Brandon L. "Full Scale Experimental Testing of Partially Composite Precast Concrete Sandwich Panels." DigitalCommons@USU, 2018. https://digitalcommons.usu.edu/etd/6982.
Full textAbstract:
Precast concrete sandwich panels are a structural system consisting of concrete layers with insulation layers in between. The concrete layers are connected through the insulation with specially designed connectors. For engineers to properly design and analyze the strength characteristics of sandwich panels and their connectors, the engineers need to obtain recommendations from the individual connector manufacturers, which can be a very rigorous process. This project tested eight full scale precast concrete sandwich panels with two concrete layers on either side of an insulation layer with connectors concentrated at either end of each panel. The objectives of this project were to evaluate the interaction between the two concrete layers and how well the connectors transferred forces between the layers (percent of composite action) and to validate simplified methods of predicting properties of the panels by comparing the predicted panel properties to the results of the testing series. Additionally, this study evaluated the panel’s different thicknesses and lengths and compared their results.
39
Hurley, Joshua Daniel. "AN EXPERIMENTAL INVESTIGATION OF THERMAL BEHAVIOR OF AN AUTOMOTIVE REAR AXLE." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1244483779.
Full text
40
Al-lami, Karrar Ali. "Experimental Investigation of Fiber Reinforced Concrete Beams." PDXScholar, 2015. https://pdxscholar.library.pdx.edu/open_access_etds/2296.
Full textAbstract:
Shear strength of fiber reinforced concrete beams was studied in this research project. Three types of fibers were examined: hooked-end steel fiber, crimped-steel fiber, and crimped-monofilament polypropylene fibers. The experimental program included five beam specimens. Two of the beams were control specimens in which one was reinforced with minimum shear reinforcement according to ACI 318, while the other one did not have any shear reinforcement. Each one of the other three specimens was reinforced with one of the above mentioned fibers by 1% volumetric ratio. In addition to the beam specimens, three prisms were also made for each type fiber to determine their toughness.
The aim of this research was to investigate the following questions for medium-high concrete strength 1) to evaluate the effectiveness of each type of fibers on the shear strength, 2) to investigate the shear strength, toughness, crack patterns and near ultimate load crack width of each beam, and 3) to determine if using 1% volumetric ratio of fibers as shear reinforcement in beams would provide adequate strength and stiffness properties comparable to reinforcing steel used as minimum shear reinforcement.
The results showed that all three types of fibers increased the shear capacity of the beam specimens more than the beam reinforced with minimum shear reinforcement. Moreover, some of the fibers used could shift the type of failure from a pure shear failure to a combined flexural-shear or pure flexural failure.
41
Wilson, John Michael Richford. "A theoretical and experimental investigation into the dynamic behaviour of soils." Thesis, University of Cambridge, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236126.
Full textAbstract:
The dynamic properties of Leighton Buzzard sand have been investigated using a resonant column test apparatus. These data are compared with very low frequency cyclic tests on identical specimens. The comparison indicates that the properties of dry sand are independent of frequency, while those of fluid saturated sand are sensitive to the viscosity of the fluid and therefore to the frequency of oscillations. A one-dimensional model of kinematic hardening plasticity is used to predict the dynamic behaviour of the sand. The input parameters for this model are based on the results of static tests. These may be conducted on standard laboratory equipment with only minor modifications. The predictions are in good agreement with the measured data. In particular, the frequency response close to resonance is correctly shown to be asymmetric and the reduction in the resonant frequency with increasing strain amplitude is also correctly represented. The model has been used to generate a series of design curves that allow the dynamic behaviour of foundations to be predicted. Two design examples are given; an offshore gravity structure and a radar installation. The input parameters are based on a hyperbolic shear stress-shear strain equation for the soil. The practical consequences of these findings are assessed with regard to soil testing procedures and dynamic analyses of foundations.
42
Grimmelsman, Kirk Alexander Aktan A. E. "Experimental characterization of towers in cable-supported bridges by ambient vibration testing /." Philadelphia, Pa. : Drexel University, 2006. http://hdl.handle.net/1860/1222.
Full text
43
Gray, Jeremy C. "Testing the Major Theories Concerning the Evolution of Sex using Experimental Evolution." Thesis, University of Auckland, 2011. http://hdl.handle.net/2292/8311.
Full textAbstract:
The evolution of sexual reproduction has been dubbed "the queen of problems in evolutionary biology". While there is a large amount of theory about the evolution of sex, there is relatively little well controlled empirical data. This thesis is an attempt to use an experimental evolution based approach in order to provide empirical insights into two different areas in the evolution of sex: the relative effects of beneficial and detrimental mutations on sex, and the effect of migration and gene flow on adaptation to new environments. In order to undertake this, a system comprising [i.e. comprised] of two Saccharomyces cerevisiae strains isogenic except for the ability to undergo sex was used. Theories about the evolution of sex can be broadly grouped into those which provide advantages for accumulating beneficial and clearing detrimental mutations. An empirical determination of their relative effects is useful in determining which theories are likely to be important to the evolution and maintenance of sexual reproduction. The first experiment consisted of propagating the sexual and asexual S. cerevisiae lines, as well as lines with increased mutation rates under both directional and stabilising selection for approximately 300 generations. The sexual lines increased in fitness significantly more quickly than the asexual lines under directional selection, regardless of mutation rate. In contrast, no lines, regardless of sexual status or mutation rate decreased or increased in fitness over the course of the experiment under stabilising selection, indicating that standard asexual selection was adequate to remove the vast majority of detrimental mutations. Thus in this experiment, sex is of much greater importance in accumulating beneficial mutations than in clearing detrimental mutations. The second experiment attempted to understand the effects of sexual reproduction and gene flow on adaptation. Predictions state that sexual organisms will be at a disadvantage to asexuals when adapting to multiple niches with migration between them, as maladapted hybrids are formed when mating occurs outside niches. To test this, sexual and asexual S. cerevisiae were adapted for approximately 350 generations to two differing environments, with varying rates of migration between them. In contrast to predictions, sexual lines showed higher adaptation to the new environments than asexuals irrespective of migration rate. The cause of this was investigated, and found to be caused by a loss of the trade off between the two environments in those treatments with high migration rates. This is interpreted as selection for generalists occurring in those lines which experience both environments. In summary, this thesis uses a powerful S. cerevisiae system in order to gain empirical insights into the evolution of sexual reproduction. The experiments further previous work with the same system into more complex and realistic scenarios, and provide novel empirical insights into the understanding of the evolution and maintenance of sex
44
Zhao, Gui Quan. "Design, control and experimental testing of intelligent variable dual-fuel automotive engines." Thesis, University of Macau, 2017. http://umaclib3.umac.mo/record=b3691635.
Full text
45
Kong, Lingzhe. "Experimental investigation of the tolerant wind tunnel for unsteady airfoil motion testing." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/29992.
Full textAbstract:
Previously, the concept of the tolerant wind tunnel, developed in the Department of Mechanical Engineering, U. B. C., was tested only for stationary models. In the present study, the concept is investigated for unsteady airfoil motion. The new wind tunnel test section, using the opposite effects of solid and open boundaries, is a new approach to reduce wall blockage effects. Consisting of vertical airfoil slats uniformly spaced on both side walls in the test section, it is designed to produce a nearly free-air test environment for the test model, which leads to negligible or small corrections to the experimental results. The performance of this wind tunnel for unsteady model testing is examined experimentally
with a two-dimensional NACA 0015 airfoil in a simple plunging sinusoidal motion. The airfoil is mounted vertically in the center plane of the test section between solid ceiling and floor. An oscillating table is designed to give the airfoil an accurate plunging sinusoidal motion. A full range of open area ratio is tested by varying the number
of slats mounted inside the side walls. Pressure distribution along the airfoil surface and displacement of the airfoil are measured as functions of time by a data acquisition system designed for this research. Lift and moment are obtained by integration of the pressure distribution at every time increment.
Using a numerical model based on the singularity distribution method, the free air case results for a NACA 0015 airfoil in the same unsteady motion are obtained. Comparison with the linear theory results by Sears¹ are discussed. Comparing with the numerical and the linear theory results, the experimental investigation shows that the new test section produces low-correction data.Applied Science, Faculty of
Mechanical Engineering, Department of
Graduate
46
Cai, Yanyan. "An experimental study of non-coaxial soil behaviour using hollow cylinder testing." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11214/.
Full textAbstract:
Non-coaxiality of the principal stress direction and principal strain increment direction has been observed in both numerical modelling and experimental studies. The importance of non-coaxiality has been widely recognised in the geomechnical engineering. Without considering the non-coaxiality in the design may lead to an unsafe soil structure. Therefore, it is essential to understand the non-coaxial soil behaviour better and take it into account in the numerical modelling. A new Hollow Cylinder Apparatus in Nottingham Centre of Geomechanics (NCG) has been employed in this study. A series of preliminary tests have been carried out to validate the reliability and repeatability of the testing results. Three series of tests, including 24 tests on Portaway sand and 2 tests on Leighton Buzzard sand, were conducted to study the non-coaxial soil behaviour of granular materials. The three stress paths followed were monotonic loading along fixed principal stress direction, pure rotation of the principal stress axes with constant deviator stress and combined rotation of principal stress axes with increasing deviator stress. Portaway sand was chosen because it has been used in NCG to investigate granular soil behaviour. Therefore, stress-strain behaviour including non-coaxial behaviour can be observed and used by the other researchers in NCG to develop or verify numerical models. The evidence of non-coaxiality has been obtained from the tests. In general, the non-coaxiality is relatively small in monotonic loading tests, but is more significant in the pure rotation tests and combined loading tests. The degree of non-coaxiality is affected by the density of the specimen, the stress path followed, the stress level and the material particle properties.
47
Saunders, Craig John. "Efficient implementation and experimental testing of transductive algorithms for predicting with confidence." Thesis, Royal Holloway, University of London, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.392660.
Full textAbstract:
Support Vector Machines (SVM's) and other kernel based methods have grown in popularity in recent years. Although they have many benefits, such as the ability to deal with a large number of parameters, one drawback of these successful techniques is their lack of the ability to provide rigorous confidence measures for the predictions they make. This thesis is devoted to the efficient implementation and experimental testing of transductive algorithms developed at the computer science department, Royal Holloway. The algorithms are tested against several benchmark data sets, and methods for comparing quantitative confidence values are described and evaluated. These techniques and other machine-learning methods are also applied to the industrial application of fault diagnosis and automated repair. An extensive case study of applying these machine learning techniques to a real-world problem is carried out. Many problems such as data collection and representation -- which are common to most real-world applications of machine learning techniques, but sometimes over-sighted in literature -- are highlighted and discussed.
48
Hartnagel, Bryan A. "Inelastic design and experimental testing of compact and noncompact steel girder bridges /." free to MU campus, to others for purchase, 1997. http://wwwlib.umi.com/cr/mo/fullcit?p9841147.
Full text
49
Barnwell, Nicholas Valgardson. "Experimental Testing of Shallow Embedded Connections Between Steel Columns and Concrete Footings." BYU ScholarsArchive, 2015. https://scholarsarchive.byu.edu/etd/4428.
Full textAbstract:
Shallow embedded column connections are widely used for columns resisting gravity loads in current design methods. These connections are usually considered “pinned” for structural analysis. In reality these connections fall in between a fixed and a pinned condition. Although methods exist to estimate the stiffness and strength of exposed columns or embedded columns under lateral loads, little research has been done to determine the strength of shallow embedded columns. An experimental study was carried out to investigate the strength of these connections. A total of 12 specimens with varying orientation, embedment depth, and column size were loaded laterally until failure or significant loss in strength. The results showed that shallow embedded connections are 86%-144% stronger in yielding and 32%-64% stronger in ultimate strength than current design methods would predict. This strength comes from a combination of the embedment depth and the resistance from the base plate and anchor rods. A model is proposed to explain the strength of the specimens and to conservatively estimate the strength of specimens with different variables. The specimens also exhibited stiffness ranging from 50%-75% of what would be expected from fully embedded columns.
50
POZZI, NICOLA. "Numerical Modeling and Experimental Testing of a Pendulum Wave Energy Converter (PeWEC)." Doctoral thesis, Politecnico di Torino, 2018. http://hdl.handle.net/11583/2708896.
Full textAbstract:
The research activities described in the present work aims to develop a pendulum converter (PeWEC: Pendulum Wave Energy Converter) for the Mediterranean Sea, where waves are shorter, thus with a higher frequency. In particular, the Pantelleria Island site wave climate is assumed as reference. The research activities started from the preliminary investigation of the working principle validity in the case of the Mediterranean Sea wave characteristics, taking into account a 1:45 scale prototype. The numerical model reliability and the success of experimental tests motivated the design and development of a 1:12 scaled device, useful for a deeper investigation of the technology capabilities and performances. Globally, the technology readiness level (TRL) was increased from 1 to 4. Important effort were focused in the development of a reliable model-based design and optimization methodology for the investigation of a full scale configuration. The latter was widely used to identify a preliminary full scale configuration and to assess the economic viability of the PeWEC technology in the Mediterranean Sea context. Results were benchmarked against the ISWEC pilot plant, deployed in 2015, in Pantelleria Island. One of the major outcomes of this analysis is a detailed overview of the advantages and drawbacks of an active (ISWEC) and a passive (PeWEC) technology, together with
some guidelines for the improvement of this technology.