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Dissertations / Theses on the topic 'Tensile strains'

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Published: 25 May 2024

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1

Lin, Muh-ren. "Experimental investigation of temperature effect on uniaxial tensile test /." The Ohio State University, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487266011224679.

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2

Leung, Ming Yan. "Dynamic characterization of micro scale samples using the Hopkinson tensile bar technique /." View abstract or full-text, 2007. http://library.ust.hk/cgi/db/thesis.pl?MECH%202007%20LEUNG.

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3

Win, San San Civil &amp Environmental Engineering Faculty of Engineering UNSW. "Tensile strength of compacted soils subject to wetting and drying." Awarded by:University of New South Wales. School of Civil and Environmental Engineering, 2006. http://handle.unsw.edu.au/1959.4/31157.

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Knowledge of the stress-strain relationship of the compacted soils in tension is of importance for understanding of cracking that occurs in earth structures, in particular embankment dams and landfill barriers. Understanding the correlation between tensile properties and traditional soil parameters and soil suction is essential in identifying problems associated with desiccation induced cracking. A series of extensive laboratory experiments were performed on three different soils from existing embankment dams. This thesis concentrated on the investigation of tensile strength in relation to the type of soil, compaction water content, compaction density ratio, rate of loading, soil suction, moisture retention characteristics and the effect of drying and wetting. Stress-strain behaviour and tensile properties indicated a dependence on soil type and compaction criteria. The plasticity index, clay content and type of mineral has shown a significant influence on tensile strength. Compaction dry of optimum resulted in an increase in strength. Compaction wet of optimum showed a decrease in strength and small increase in strain at failure. Higher compaction effort resulted in higher tensile strength, tensile stiffness and brittle stress-strain behaviour. Difference in loading rate revealed response time for initial tensile deformation as well as sustainable duration up to failure point. The effect of soil suction plays an important role in drying during which specimens exhibited a considerable strength increase. The magnitude of strength increase may have been contributed by a combination of suction, air entry value and compaction density. The effect of wetting could cause decreasing in suction and thus a reduction in strength. Based on the findings, it was concluded that the desiccation-induced may not necessarily occur due to an associated increase in tensile strength. However, an increase in tensile strength is likely to be accompanied by an increase in shrinkage. Therefore, desiccation-induced cracking is related to the interaction between moisture loss, change in soil suction, tensile stress and shrinkage.
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4

Vorakunpinij, Adisak. "The effect of paper structure on the deviation between tensile and compressive responses." Diss., Georgia Institute of Technology, 2003. http://hdl.handle.net/1853/7058.

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5

Roth, Michael Jason 1975. "Flexural and tensile properties of thin, very high-strength, fiber-reinforced concrete panels." Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-11062007-215816.

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6

Yang, Yang. "Stress intensity factors of circumferential semi-elliptical internal surface cracks of tubular member subjected to axial tensile loading." Thesis, University of Macau, 2010. http://umaclib3.umac.mo/record=b2182941.

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7

Clarke, Jo Ann Marie Carleton University Dissertation Engineering Mechanical. "High strain rate tensile testing." Ottawa, 1993.

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8

Sasazaki, Yoshihiro. "Ultrastructure of articular cartilage under tensile strain." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.410724.

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9

Ouyang, Xin. "CONSTITUTIVE EQUATIONS OF RUBBER UNDER LARGE TENSILE STRAIN AND HIGH STRAIN RATES." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1154146622.

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10

Berry, Catherine Cecilia. "The influence of tensile strain on fibroblasts in culture." Thesis, Queen Mary, University of London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.271478.

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11

Saloustros, Savvas. "Tracking localized cracks in the computational analysis of masonry structures." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461714.

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Numerical methods aid significantly the engineering efforts towards the conservation of existing masonry structures and the design of new ones. Among them, macro-mechanical finite element methods based on the smeared crack approach are commonly preferred as an affordable choice for the analysis of large masonry structures. Nevertheless, they usu-ally result in a non-realistic representation of damage as smeared over large areas of the structure, which hampers the correct interpretation of the damage pattern. Additionally, a more critical pathology of this approach is the mesh-dependency, which influences nota-bly the safety and stability predictions. To overcome these limitations, this thesis proposes a novel computational tool based on the {enrichment} of the classical smeared crack approach with a local tracking algorithm. The objective of this localized damage model is the realistic and efficient non-linear anal-ysis of masonry structures with an enhanced representation of cracking. The non-linear behaviour of masonry is simulated through the adoption of a continuum damage mechanics model with two damage indices, allowing the differentiation between the tensile and compressive mechanical responses of masonry. In this context, a novel explicit formulation for the evolution of irreversible strains is proposed and implemented. Two new expressions are derived for the regularization of the tensile and compressive softening responses according to the crack-band approach, ensuring the mesh-size objec-tivity of the damage model. The simulation of the structural behaviour of masonry structures under versatile loading and boundary conditions necessitates some developments in the context of local tracking algorithms. To this end, this thesis presents the enhancement of local tracking algorithms with novel procedures that make possible the simulation of multiple, arbitrary and inter-secting cracking under monotonic and cyclic loading. Additionally, the effect of different crack propagation criteria is investigated and the selection among more than one potential failure planes is tackled. The proposed localized damage model is validated through the simulation of a series of structural examples. These vary from small-scale tests on concrete specimens with few dominant cracks, to medium and large-scale masonry structures with multiple tensile, shear and flexural cracking. The analyses are compared with analytical, experimental and numerical results obtained with alternative methods available in the literature. Overall, the localized damage model developed in this thesis largely improves the mesh-independency of the classical smeared crack approach and reproduces crack patterns and collapse mech-anisms in an efficient and realistic way.
Los métodos numéricos son decisivos en la ingeniería para la conservación de estructuras de mampostería existentes y el diseño de estructuras nuevas. Entre ellos, los métodos macro-mecánicos de elementos finitos, basados en el concepto de fisuras distribuidas, son habitualmente los preferidos como opción asequible para el análisis de grandes estructuras de mampostería. Sin embargo, suelen resultar en a una representación poco realista del daño, distribuido en grandes áreas de la estructura, lo que impide la correcta interpretación del patrón de daño. Además, esta metodología presenta una patología más crítica, la dependencia de la malla, que influye notablemente en las predicciones de seguridad y estabilidad. Para superar estas limitaciones, esta tesis propone una nueva herramienta numérica basada en el enriquecimiento del clásico enfoque de fisuras distribuidas con un algoritmo de trazado local. El objetivo de este modelo de daño localizado es el análisis no-lineal de las estructuras de mampostería de manera realista y eficiente con una representación mejora-da de fisuras. El comportamiento no lineal de la mampostería se simula a través de la adopción de un modelo de mecánica de daño continuo con dos índices de daño, permitiendo la diferenciación entre las respuestas mecánicas de tensión y compresión de la mampostería. En este contexto, se propone e implementa una nueva formulación explícita para la evolución de deformaciones irreversibles. Se derivan dos nuevas expresiones para la regularización del ablandamiento de tracción y compresión según el ancho de banda de la fisura, garantizan-do la objetividad del modelo de daño al respecto del tamaño de la malla. La simulación del comportamiento estructural de las estructuras de mampostería en condiciones de carga y contorno generales precisa de algunos desarrollos en el contexto de los algoritmos locales de trazado. Con este objetivo, se presenta la mejora de los algoritmos locales de trazado con nuevos procedimientos que posibilitan la simulación de fisuración múltiple, arbitraria e secante bajo cargas monótonas y cíclicas. Además, se investiga el efecto de diferentes criterios de propagación de fisuras y se aborda la selección entre más de un plano de falla posible. El modelo de daño localizado propuesto se valida mediante la simulación de una serie de ejemplos estructurales. Éstos van desde pruebas a pequeña escala en probetas de hormigón, con pocas fisuras dominantes, hasta estructuras de mampostería de mediana y gran escala con fisuración múltiple de tracción, de cortante y de flexión. Los análisis se comparan con los resultados analíticos, experimentales y numéricos obtenidos con métodos alternativos disponibles en la literatura. El modelo de daño localizado mejora en gran medida la independencia de la malla del clásico método de fisuras distribuidas y reproduce patrones de daño y mecanismos de colapso de una manera eficiente y realista
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12

Fowler, John Paul. "Damage evolution in ductile materials at high rates of tensile strain." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1997. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp04/mq22111.pdf.

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13

Siddiqui, Md Tareq. "Scaling studies on the tensile strain rate sensitivity of laminated composites." Thesis, Wichita State University, 2011. http://hdl.handle.net/10057/5207.

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The stress-strain behavior and failure of composite materials are strain rate sensitive, and influenced by the dimensions of the structure. To elucidate the combined effects of scaling and strain rate on the strength of unnotched continuous fiber reinforced composites, an experimental investigation has been conducted on Newport NB321/7781 fiberglass/epoxy and Toray T800/3900-2B unitape/epoxy materials. The experimental results have been characterized in terms of failure strength, failure modes and the Weibull modulus m. A 2D-scaling approach has been followed and composite coupons were fabricated with [0]4 and [±45]s stacking sequences. The experimentation has been conducted at strain rates ranging from quasi-static (0.0002 s^-1) to high strain rate (50 s^-1), to study the mechanical responses and associated failure modes. Subsequently, the Weibull statistical model was utilized to characterize the scaling behavior at different strain rates. The average failure stress of [0]4 carbon, [0]4 fiberglass and [±45]s fiberglass specimens were observed to decrease with increasing specimen size at each strain rate. However, at high strain rate, the percentage of strength reduction was observed to be lower in comparison to the quasi-static strain rate. Owing to the free edge effects, the scaling effect was maximum for [+45/-45]s carbon unitape specimens. But unlike the other stacking sequences, the percentage of strength reduction at higher strain rates was higher compared to quasi-static strain rate, indicating increased scaling effects with strain rate. Weibull modulus m for the specimens tended to increase with increasing strain rate indicating diminishing scaling effects, while [+45/-45]s carbon specimens exhibited opposite trend. Failure at multiple locations was observed in larger coupons at high strain rate, which results in size and strain rate dependent fracture behavior.
Thesis (M.S.)--Wichita State University, College of Engineering, Dept. of Aerospace Engineering.
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14

Kukatla, Harish C. "A Study of Strain Elastography Under a Normal Tensile Testing Condition." Youngstown State University / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ysu1296334599.

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15

Fowler, John Paul Carleton University Dissertation Engineering Mechanical. "Damage evolution in ductile materials at high rates of tensile strain." Ottawa, 1996.

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16

Goley, Patrick Stephen. "Plastic Relaxation of Highly Tensile Strained (100) Ge/InGaAs Heterostructures." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/54944.

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Biaxial tensile strain has been shown to greatly enhance the optoelectronic properties of epitaxial germanium (Ge) layers. As a result, tensile-Ge (and#949t-Ge) layers grown on larger lattice constant InGaAs or GeSn have attracted great research interest. However, no previous studies have investigated the plastic relaxation occurring in these and#949t-Ge layers. Here, we experimentally demonstrate that plastic relaxation occurs in nearly all and#949t-Ge epitaxial layers that are of practical interest for optoelectronic applications, even when layers may still exhibit strain-enhanced characteristics. We show arrays of misfit dislocations (MDs), which are mostly disassociated, form at the and#949t-Ge/InGaAs interface for and#949t-Ge layers as thin as 15 nm with less than 1% total mismatch. Wedge geometry of plain view transmission electron microscopy (PV-TEM) foils is utilized to carry out a depth dependent investigation MD spacing for a range of and#949t-Ge/InGaAs heterostructures. MD spacing measured by PV-TEM is correlated to and#949t-Ge layer relaxation measured by high-resolution x-ray diffraction. We confirm very low relaxation (< 10% relaxed) in and#949t-Ge layers does not imply they have been coherently grown. We demonstrate plastic relaxation in the and#949t-Ge layer is acutely sensitive to grown-in threading dislocations (TDs) in the template material, and that reducing TD density is critical for maximizing strain retention. Given that and#949t-Ge layer thicknesses of 150+ nm with greater than 1% tensile strain are desired for optoelectronic devices, this work suggests that MDs may inevitably be present at and#949t-Ge/InGaAs heterointerfaces in practical devices, and that the effect of MDs on optoelectronic performance must be better understood.
Master of Science
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17

Zrir, Mohammad ali. "Tensile-strained and highly n-doped Germanium for optoelectronic applications." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4036/document.

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Dans le cadre de ce travail de thèse, nous avons étudié une approche permettant de réaliser les composants d'émission de la lumière basés sur les couches epitaxiées de Ge contraint en tension et fortement dopé de type n. Afin de créer de contrainte en tension dans les films épitaxiés de Ge, nous avons investi deux méthodes : faire croître du Ge sur InGaAs ayant un paramètre de maille plus grand que celui de Ge, et faire croître du Ge sur Si, en prenant l'avantage du coefficient de dilatation thermique du Ge, qui est deux fois plus grand que celui du Si. Concernant la croissance de Ge sur les substrats Si, nous avons étudié deux orientations cristallines, <001> and <111>, afin de pouvoir comparer la valeur de contrainte en tension obtenue et aussi la densité des dislocations émergeantes. Le dopage de type n dans le Ge a été effectué en utilisant le phosphore et l'antimoine. Nous avons montré que quand le dopage est effectué à des températures relativement basses et suivi d'un recuit thermique rapide, de concentration d'électrons électriquement activés de ~ 4x10^19 cm-3, a pu être obtenue. Cette valeur représente l'un des meilleurs résultats expérimentalement obtenus jusqu'à présent. Des mesures de recombinaison radiative par spectroscopie de photoluminescence effectuées à température ambiante ont mis en évidence une augmentation de l'émission du gap direct de Ge d'environ 150 fois. Finalement, nous avons étudié les effets de la barrière de diffusion sur l'efficacité de dopage pendant les recuits thermiques. Une comparaison sur l'efficacité de trois barrières de diffusion, Al2O3, HfO2 and Si3N4, sera présentée et discutée
During my thesis, we studied approaches to achieve light-emitting devices based on tensile strained and highly n-doped Ge epitaxial films. In order to create an elastic tensile strain in the epitaxial Ge films, we have investigated two methods: The epitaxial growth of Ge on InGaAs buffer layers that have a larger lattice constant, and the epitaxial growth of Ge on Si, by which we take benefit of the thermal expansion coefficient of Ge which is twice greater than that of Si. Concerning the growth of Ge on Si substrates, we have studied two crystalline orientations, <001> and <111>, in order to compare the values of the accumulated tensile strain and also the density of threading dislocations. The n-type doping in Ge was performed using a co-doping technique with phosphorus (P2 molecule) and antimony (Sb). We demonstrated that the dopants sticking coefficient leads to dopant incorporation in the Ge film larger than their solid solubility, which generally increases with increasing substrate temperature. As a result, when the doping is carried out at relatively low temperatures and followed by rapid thermal annealing, electrically activated electron concentration of 4x1019 cm-3 was demonstrated. This value is one of the best results obtained experimentally so far. The radiative recombination, at RT, measured by photoluminescence spectroscopy showed an increase in the direct gap emission of Ge of about 150 times. Finally, we studied the effects of diffusion barrier on the doping concentration during the thermal annealing. A comparison between the advantages of three diffusion barriers, Al2O3, HfO2 and Si3N4, will be presented and discussed
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18

Verteramo, Alberto Paolo. "Cartilage response to high strain rates in impact and tensile loading modes." Thesis, University of Leeds, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424058.

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19

Mak, Yew-Poh. "Strain rate effects on tensile fracture and damage tolerance of composite laminates." Thesis, Massachusetts Institute of Technology, 1992. http://hdl.handle.net/1721.1/43256.

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Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1992.
Title as it appears in the June, 1992 MIT Graduate List: Strain rate effects on tensile failure and damage tolerance of composite laminates.
Includes bibliographical references (leaves 133-138).
by Yew-Poh Mak.
M.S.
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20

Rutherford, Benjamin Andrew. "Beneficial Tensile Mean Strain Effects on the Fatigue Behavior of Superelastic NiTi." Thesis, Mississippi State University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10266594.

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In this work, beneficial effects of tensile mean strain on fatigue behavior and microstructure of superelastic NiTi (i.e. Nitinol) are studied. Most applications, such as endovascular stents made with NiTi, are subjected to a combination of constant and cyclic loading; thus, understanding the fatigue behavior of NiTi undergoing mean strain loading is necessary. Cyclic strain-controlled fatigue tests are designed to investigate the effects of tensile mean strain on fatigue of superelastic NiTi. Experimental observations show that combinations of large tensile mean strains and small strain amplitudes improve the fatigue life of superelastic NiTi. This behavior arises from reversible, stress-induced phase transformations. The phase transformations cause “stress plateaus” or strain ranges with no change in stress value. Scanning electron microscopy (SEM) of the fracture surfaces of specimens revealed generally short crack growth. Electron backscatter diffraction (EBSD) found the amount of residual martensite to be about ~8%, regardless of loading conditions.

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21

Johnson, David Thomas. "Deformation mechanisms in ABS polymers." Thesis, Cranfield University, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.341042.

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22

Bartels, Peter Atwood. "Net section rupture in tension members with connection eccentricity." Morgantown, W. Va. : [West Virginia University Libraries], 2000. http://etd.wvu.edu/templates/showETD.cfm?recnum=1497.

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Thesis (M.S.)--West Virginia University, 2000.
Title from document title page. Document formatted into pages; contains x, 101 p. : ill. (some col.) Includes abstract. Includes bibliographical references (p. 77-80).
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23

Falola, Adekunle Samuel. "MECHANICAL CHARACTERIZATION – MONOTONIC MICRO-TENSILE, STRESS RELAXATION, AND STRAIN-CONTROLLED CYCLIC STRESS-STRAIN RESPONSES OF SINGLE ELECTROSPUN PVDF NANOFIBERS." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1564557199987647.

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24

Clavel, Michael Brian. "Tensile-Strained Ge/InₓGa₁₋ₓAs Heterostructures for Electronic and Photonic Applications." Thesis, Virginia Tech, 2015. http://hdl.handle.net/10919/78129.

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The continued scaling of feature size in silicon (Si)-based complimentary metal-oxide-semiconductor (CMOS) technology has led to a rapid increase in compute power. Resulting from increases in device densities and advances in materials and transistor design, integrated circuit (IC) performance has continued to improve while operational power (VDD) has been substantially reduced. However, as feature sizes approach the atomic length scale, fundamental limitations in switching characteristics (such as subthreshold slope, SS, and OFF-state power dissipation) pose key technical challenges moving forward. Novel material innovations and device architectures, such as group IV and III-V materials and tunnel field-effect transistors (TFETs), have been proposed as solutions for the beyond Si era. TFETs benefit from steep switching characteristics due to the band-to-band tunneling injection of carriers from source to channel. Moreover, the narrow bandgaps of III-V and germanium (Ge) make them attractive material choices for TFETs in order to improve ON-state current and reduce SS. Further, Ge grown on InₓGa₁₋ₓAs experiences epitaxy-induced strain (ε), further reducing the Ge bandgap and improving carrier mobility. Due to these reasons, the ε-Ge/InₓGa₁₋ₓAs system is a promising candidate for future TFET architectures. In addition, the ability to tune the bandgap of Ge via strain engineering makes ε-Ge/InₓGa₁₋ₓAs heterostructures attractive for nanoscale group IV-based photonics, thereby benefitting the monolithic integration of electronics and photonics on Si. This research systematically investigates the material, optical, and heterointerface properties of ε-Ge/InₓGa₁₋ₓAs heterostructures on GaAs and Si substrates. The effect of strain on the heterointerface band alignment is comprehensively studied, demonstrating the ability to modulate the effective tunneling barrier height (Ebeff) and thus the threshold voltage (VT), ON-state current, and SS in future ε-Ge/InₓGa₁₋ₓAs TFETs. Further, band structure engineering via strain modulation is shown to be an effective technique for tuning the emission properties of Ge. Moreover, the ability to heterogeneously integrate these structures on Si is demonstrated for the first time, indicating their viability for the development of next-generation high performance, low-power logic and photonic integrated circuits on Si.
Master of Science
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25

Chen, Yu-Szu. "Testing and modeling tensile stress-strain curve for prestressing wires in railroad ties." Thesis, Kansas State University, 2016. http://hdl.handle.net/2097/32582.

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Master of Science
Department of Civil Engineering
Robert J. Peterman
Prestressed concrete is commonly used for bridges, pavement and railroad ties because of economic advantages in cost, sustainability service life, and environmental friendliness. In general concrete design standard, the ultimate moment strength in flexure design is computed by finding the equilibrium of the internal force in the section (the compressive force in concrete and tension force in the steel and reinforcement). To predict tension force in steel one generally applies the 7-wire low-relaxation prestressing strand equation from the PCI manual even though the design employed prestressing wires instead of strand. The other method is to use equations from the ACI Code which is over conservative. Considering both approaches are lack accuracy, this research will provide an accurate estimation of the stress in prestressing wires through an experimental program and analytical modeling. The real stress-strain curves are collected through experimental testing in 13 types of prestressing wire. Experimental results are then used for modeling existing equations. As a result a more precise estimation is achieved. Additionally, this research simplifies the procedure for utilizing the equations which offers convenience in practical application.
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26

Umberger, Pierce David. "Modeling the High Strain Rate Tensile Response and Shear Failure of Thermoplastic Composites." Diss., Virginia Tech, 2013. http://hdl.handle.net/10919/23846.

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The high strain rate fiber direction tensile response of Ultra High Molecular Weight Polyethylene (UHMWPE) composites is of interest in applications where impact damage may occur. This response varies substantially with strain rate. However, physical testing of these composites is difficult at strain rates above 10^-1/s. A Monte Carlo simulation of composite tensile strength is constructed to estimate the tensile behavior of these composites. Load redistribution in the vicinity of fiber breaks varies according to fiber and matrix properties, which are in turn strain rate dependent. The distribution of fiber strengths is obtained from single fiber tests at strain rates ranging from 10^-4/s to 10^-1/s and shifted using the time-Temperature Superposition Principle (tTSP) to strain rates of 10^-4/s to 10^6/s. Other fiber properties are obtained from the same tests, but are assumed to be deterministic. Matrix properties are also assumed to be deterministic and are obtained from mechanical testing of neat matrix material samples. Simulation results are compared to experimental data for unidirectional lamina at strain rates up to 10^-1/s. Above 10^-1/s, simulation results are compared to experimental data shifted using tTSP. Similarly, through-thickness shear response of UHMWPE composites is of interest to support computational modeling of impact damage. In this study, punch shear testing of UHMWPE composites is conducted to determine shear properties. Two test fixtures, one allowing, and one preventing backplane curvature are used in conjunction with finite element modeling to investigate the stress state under punch shear loading and the resulting shear strength of the composite.
Ph. D.
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27

Das, Sagar. "A strain-rate dependent tensile damage model for brittle materials under impact loading." Thesis, The University of Sydney, 2016. http://hdl.handle.net/2123/15612.

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Brittle materials are often subjected to high strain rate impact load, which could be imposed due to intentional demolition purposes or during ballistic impact on protective structures. Fragments of different sizes are generally observed by such impact, which are directly related to the strain rate experienced by the material at different locations. This thesis presents a rate-dependent constitutive model to predict such dynamic behaviour of brittle solid under tensile loading. A three-parameter rate dependent tensile damage model, under continuum mechanics framework, is developed for simulating the fragmentation of brittle materials subjected to high strain-rate loading. The damage model is formulated under the assumption that the isotropic and homogeneous material contains initial microcracks and the microcrack induced damage increases when a critical volumetric strain is exceeded. Considering the microcrack induced damage and energy into account, a quantitative and direct method is developed to determine the fragment size under a constant strain rate loading. In this model, instead of assuming spherical fragment, more realistic prolate spheroid fragment is assumed, which eventually determines the more accurate surface energy from a fragment. In addition, complete strain energy (until the fracture of the material) is considered which improves the global energy balance in predicting the size of a fragment. The parameters of this model can be conveniently calibrated by experimental data on fracture strength and strain rate. The proposed rate-dependent model is validated by a spall experiment of concrete and with a dynamic Brazilian disc experiment of sandstone. Both of these experiments are numerically simulated with the proposed model and the experimental observations are compared with the simulation. The predicted strain rate, fracture strength, fracture location and fragment size are in very good agreement with those obtained in the experiments.
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Lam, Daniel F. "STRAIN CONCENTRATION AND TENSION DOMINATED STIFFENED AEROSPACE STRUCTURES." University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1145393262.

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29

Guenther, Cristy Louise. "Evaluation of shear and diagonal tension in plain concrete." Laramie, Wyo. : University of Wyoming, 2007. http://proquest.umi.com/pqdweb?did=1400964851&sid=1&Fmt=2&clientId=18949&RQT=309&VName=PQD.

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30

Way, Louise. "The use of a novel miniature strain device to investigate the response of tendon cells to In vitro tensile strain." Thesis, University of Sheffield, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.574561.

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The aim of this work was to study the cell biology of tendons and their response to in vitro tensile strain with a view to elucidating how cells sense mechanical load and what changes occur to the cells in response. This work was done in order to provide some scientific background to aid the improvement of strategies for the treatment and prevention of tendon damage and develop appropriate methodologies related to the mechanical stimulation of tissue engineered tendons. A miniature cyclic straining device was designed (in collaboration with Electrical Engineering) which utilised a 50ml centrifuge tube containing two clamps, controlled via a stepper motor. This was programmed using Visual Basic enabling a defined magnitude and duration of strain to be applied to the tissue or monolayer of cells within the incubator. The design offered numerous benefits over the more commonly-used commercially available bioreactors; in that the system was relatively inexpensive to make, multiple repeats could be carried out simultaneously, only comparatively small amounts of media were required and, as the device was small, it could be kept in the incubator for the duration of the experiment. This design was developed further by re-orientating the clamps and stepper motor to create a horizontal device which could be placed in a Petri-dish and used with a dipping lens con focal microscope to image the response of cells to strain in real-time. Due to the variability in primary cell attachment to the PLA surfaces, alternative methods of cell seeding were investigated. Cytocentrifugation provided a reliable method of attaching a pre-determined number of cells to the surface; cells had an improved plating efficiency and less variation in distribution, whilst remaining viable. This method was also tested on Azowipes tm, which were used as a model 3D scaffold in order to see whether this method had potential for use in tissue engineering. Cells penetrated to the centre of the scaffold, in the order of mm's, an improved penetration compared to the gravity-seeded controls. Cells continued to produce collagen and synthesise DNA after cytocentrifugation onto the 3D scaffold. Monolayer cultures of cells on collagen-coated PLA were exposed to cyclic mechanical strain in the custom-made mechanical straining devices. The effect of specific durations and magnitude of strains on cell number was compared to mono layers of cells which were either maintained in an unloaded state or experienced static tensile strain. However, monolayer cultures of cells do not accurately represent in vivo cell behaviour, as proliferation is much increased in 20 cultures as opposed to what is seen physiologically in tendon tissue. For this reason, intact rat tail tendon fascicles were investigated as they have a regular and relatively uniform composition and the cells remain in their native extracellular matrix. In situ 3D information regarding the cells residing in intact tail tendon fascicles under tension was obtained using multiphoton microscopy. Mechanical stress was applied to the fascicles and a wavelength of 900nm was used to image tendon cells stained with Acridine Orange whilst simultaneously imaging the collagen extracellular matrix using Second Harmonic Generation. The data was then used to inform 'The Virtual Tendon Project' about local variations in strain and demonstrated the requirement for 3D image processing to reliably describe local strains in the matrix. Cell proliferation in response to mechanical stimulation was studied by the uptake of EdU, a relatively new method which was optimised for tendon tissue (Way et al., 20 I 0). The EdU technology, together with histological sectioning, was used to study the effects of obesity and age on tendons in vivo. Rats were fed a high fat diet and tendons from the tail, Achilles and patellar were dissected. Fewer collagen fibres with greater inter-fibrillar spaces were seen in the histological sections taken from the Achilles of the rats fed a high fat diet and the cells had a greater proliferative index than those of the control. In the ageing studies a decrease in cell area and an increase in proliferative index were apparent in the Achilles of the mature rat compared to the 2 month old rat. The methodologies developed in this project predominantly use the simple tendons of the tail to help describe how cells residing in tendon respond to mechanical strain and together with 'The Virtual Tendon Project' go some way towards describing the complex 3D local strain environment present in this tissue.
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31

Nayeem, Mustayeen B. "Applied mechanical tensile strain effects on silicon bipolar and silicon-germanium heterojunction bipolar devices." Thesis, Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-07182005-102447/.

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Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2006.
Dr. John D. Cressler, Committee Chair ; John Papapolymerou, Committee Member ; Joy Laskar, Committee Member.
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32

Zakaria, Muzdalifah. "The influence of strain rate on the response to tensile deformation of titanium alloys." Thesis, University of Birmingham, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402525.

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Amini, Khoiy Keyvan. "Biomechanical Characterization and Simulation of the Tricuspid Valve." University of Akron / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=akron1542651986497595.

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34

Dunford, Kristin Marie. "Effect of Postmortem Time and Preservation Fluid on the Tensile Material Properties of Bovine Liver Parenchyma." Thesis, Virginia Tech, 2017. http://hdl.handle.net/10919/90179.

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The liver is one of the most frequently injured abdominal organs in motor vehicle collisions. Although previous studies have quantified the tensile failure properties of human liver parenchyma at 48hrs postmortem, it is currently unknown how the material properties change between time of death and 48hrs postmortem. Therefore, the purpose of this study was to quantify the effects of postmortem degradation on the tensile material properties of bovine liver parenchyma when stored in DMEM or saline. Fourteen fresh bovine livers were obtained from a local slaughter house and stored in either DMEM or saline as large blocks, small blocks, or slices of tissue. Multiple parenchyma dog-bone samples from each liver were tested once to failure at three time points: ~6hrs, ~24hrs, and ~48hrs postmortem. The data were then analyzed to determine if there were significant changes in the material properties with respect to postmortem time. The results showed that the failure strain decreased significantly between 6hrs and 48hrs after death when stored as large blocks in saline. Conversely, neither the failure stress nor failure strain changed significantly with respect to postmortem time when stored as large blocks in DMEM. The modulus did not significantly change for tissue stored as large blocks in either fluid. Preliminary results indicated that reducing the tissue storage size had a negative effect on the material properties and cellular architecture. Overall, this study illustrated that the effects of postmortem liver degradation varied with respect to the preservation fluid, storage time, and storage block size.
MS
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35

Abul-Hamayel, Ismat A. A. 1960. "MOMENT ROTATION CURVES FOR TOP AND SEAT CONNECTIONS (STATIC LOADING, TENSION)." Thesis, The University of Arizona, 1985. http://hdl.handle.net/10150/291311.

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Wu, Xiaoxia. "Effect of strain gradient on the nucleation of martensite in rod under tension /." View Abstract or Full-Text, 2003. http://library.ust.hk/cgi/db/thesis.pl?MECH%202003%20WU.

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Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003.
Includes bibliographical references (leaves 76-81). Also available in electronic version. Access restricted to campus users.
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37

El-Hossary, Wafaa Hassanein Hassan. "The effect of cyclic tensile strain on gene expression of cultured human periodontal ligament cells." Thesis, University of Leeds, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.509041.

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Objectives: To analyse the changes in gene expression in a population of human periodontal ligament (HPDL) cells exposed to cyclic tensile strain in a three dimensional culture system. Results: Cells derived from extracted teeth were shown to represent a mixed population with greater than 95% of cells expressing markers characteristic of periodontal ligament fibroblasts with an oestobastic phenotype with a smaller sub-population (2-3%) of stem cells. Cells from several different donors were subjected to an applied tensile strain (5%) and compared to unstressed controls. RNA extracted immediately post-stress was analysed to determine changes in gene expression. Microarray data indicated a total of 164 genes responding to the applied strain, 38% of which have no known function. qRT-PCR analysis of HAS1, NR4A2, FOS, INHBA, FOSL2, RUNX2, ATF4, FOSL1, SP7, COL1A1, COL3A1, MMP1, MMP2, MMP3 and TIMP3 expression levels confirmed the microarray data. Further analysis of the data highlighted changes in expression of CLDN4, BCOR, PROK2 and INHBA genes known to be associated with inherited orofacial disorders. Conclusion: This study has shown that the periodontal ligament fibroblasts derived from extracted teeth and cultured in vitro in 3D 'in-vivo-like' constructs can be induced to respond to mechanical stimuli. The molecular events detected in periodontal ligament cells subjected to cyclic tensile strain direct the cell population to remodel the entire periodontium (cells and matrices) in a process involving cell migration. This study presents several new findings including the first report of the involvement of HAS1, NR4A2 and FOSL2 in the response of HPDL cells to mechanical stimulation, the first report for the of modulation CLDN4, BCOR, and PROK2 genes by mechanical perturbation, and the differential induction of SP7 isoforms by mechanical stimulation in HPDL.
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Baria, Katherine Elizabeth. "Modulation of the effect of tensile strain on fibroblasts by extracellular matrix molecules and serum." Thesis, University of London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497240.

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39

Chan, Jason J. (Jason Joseph). "Design of fixtures and specimens for high strain-rate tensile testing on a drop tower." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/54529.

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Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 38-39).
Drop towers are used to perform mechanical tests at strain rates similar to those experienced in automobile crashes. By their nature, drop towers are configured to perform compression tests only. This project aims to design a set of fixtures and specimens to allow the machine to perform tensile tests. Two major design options were considered and analyzed using engineering mechanics and finite element analysis. The design selected used a double dog-bone specimen bent into a "U"-shape and impacted by a weighted force sensor with a steel tup attached to the bottom. The appropriate fixtures were designed. Future work on this project includes manufacturing of the fixtures, design and construction of a method for creating the specimens, and physical tensile tests using the new machine configuration.
by Jason J. Chan.
S.B.
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40

Sandora, Normalina. "Regeneration of decellularised tendon by human mesenchymal stem cells in response to uniaxial tensile strain." Thesis, University of Leeds, 2016. http://etheses.whiterose.ac.uk/16429/.

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Injury of ligaments is very common, and a total tear of the anterior cruciate ligament (ACL) demands replacement. Ideally, a graft for ligament replacement should be able to regenerate into a native like ligament, and restore physiological and anatomical function immediately after transplantation. The University of Leeds has developed a protocol to generate an acellular tendon scaffold derived from allograft/ xenograft using decellularisation technology. The aims of the study were to study the differentiation of human bone marrow derived multipotential stromal cells (BM-MSC) seeded onto the decellularised porcine patella tendon scaffold in response to cyclic tensile strain. Porcine patellar tendons were harvested and decellularised using the Leeds protocol. The decellularised tendon scaffolds were then characterised to determine their: (i) acellularity, (ii) histoarchitecture, (iii) extracellular matrix components (iv) levels of DNA (v) sterility, and (vi) biocompatibility. The decellularisation protocol was found to have minimal effect on the tissue histoarchitecture, and consistently generated sterile, non-toxic acellular scaffolds among different batches, with 98 – 99 % DNA removal compared to native tissue. Both porcine and human BM-MSCs were characterised using a range of antibodies to CD markers and trilineage differentiation and shown to have properties consistent with multipotential stromal cells. Human BM-MSCs were seeded directly onto appropriately sized samples of porcine patella tendon scaffolds at 1 x 105 cells.cm-2 for 12 hours, and then transferred to culture wells of TenCell-1 (a physically interactive rig for delivery of cyclic tensile strain). The cell-seeded tendon scaffolds were cultured either statically or with 4, 6 or 8 % cyclic tensile strain for 4/24 hours at 1 Hz, for 7 days. The response of the cells to cyclic tensile strain was investigated using viability assays (Live/Dead assay and ATPlite™ assay), histology, immunohistochemistry and gene expression analysis (RT-qPCR and gel electrophoresis). The mechanical properties of the scaffolds before and after incubation with cells were determined using uniaxial tensile testing. Under 4, 6 and 8 % cyclic tensile strain, the cell seeded scaffolds had a histological appearance of tendon-like tissue. When cultured under 6 and 8 % cyclic tensile strain, there was evidence that the MSCs were differentiating into tenogenic cells by expressing scleraxis, tenascin C, collagen I and collagen III genes. Cell-seeded scaffolds cultured under 6 % cyclic tensile strain had the highest viability and the matrix stiffness, was significantly increased compared to cell-seeded scaffolds cultured at 4 or 8 % cyclic tensile strain. The cell-seeded scaffolds incubated statically for 7 days showed matrix disorganization, had lower cell viability and less cell infiltration compared to samples incubated with cyclic strain.
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41

Lindmark, Jenny. "Tensile Strain Monitoring in Reinforced Concrete Using Non-Contact Full-Field Optical Deformation Measurement Systems." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-70090.

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As traffic loads increase and bridges age the need for structural health monitoring is growing. With the digitalization of our society, new non-contact full-field measurement techniques have been developed. These techniques have the potential to be used in monitoring of existing bridges. Today visual inspections are carried out every sixth year. These only give a rough estimate of the structure's health and only provide information about the surface of the structure. In addition to these inspections, traditional sensors like linear variable differential transformers and strain gauges are used to measure parameters such as displacement and strain. For existing bridges in reinforced concrete it is especially important to monitor reinforcement strains, as high strains could be indicative of overloading of the structure or even that a failure is about to occur. The methods available to measure reinforcement strain in existing bridges today are not very effective and have some limitations. The aim of this thesis is thus to evaluate the possibility to predict reinforcement strain based on surface strain measurements obtained by a non-contact full-field optical measurement system. In this study the software ARAMIS was used to measure surface strains, and traditional strain gauges were used to measure reinforcement strain. Strain distribution were evaluated at the initiation of cracks, during sections of cyclic loading and at a load close to the yielding point of the reinforcement. A correlation factor between the strain registered in the software and the strain obtained from the strain gauges was introduced. Based on the results in this study it is not possible to predict exact reinforcement strain based on surface measurements. Digital image correlation does however show potential to be used as a non-contact full-field measurement technique for in-situ measurements. Before this is reality there is still a need for further research in this area.
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42

Al-Attili, Abdelrahman. "Band-gap engineering of Germanium monolithic light sources using tensile strain and n-type doping." Thesis, University of Southampton, 2016. https://eprints.soton.ac.uk/410363/.

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Band-gap engineering of bulk germanium (Ge) holds the potential for realizing a laser source, permitting full integration of monolithic circuitry on CMOS platforms. Techniques rely mainly on tensile strain and n-type doping. In this thesis, we focus on studying diffusion-based phosphorus (P) doping of Ge using spin-on dopants (SOD), and tensile strain engineering using freestanding micro-electro-mechanical systems (MEMS)-like structures. Process development of a reliable SOD recipe was conducted using furnace and rapid-thermal annealing, and successful doping up to 2.5 x 10¹⁹cm⁻³ was achieved,resulting in approximately 10 enhancement in direct-gap emission. A transition in Ge direct-gap photoluminescence (PL) behaviour is observed upon doping, from being quadratically dependent on excitation power to linear. We have also demonstrated that the limited doping concentration of P in Ge using SOD is not source limited, but more probably related to the diffusion mechanism. The other part of the project concentrated on Ge strain engineering. Previous works reported high tensile strain values based on freestanding MEMS-like structures made of Ge, yet without embedding an optical cavity (until recently). In this project, we realize this combination by fabricating Ge micro-disks as an optical cavity on top of freestanding SiO2 structures, utilizing Ge-on- Insulator wafers (GOI). 3D computer simulations were used to understand and optimize the devices, in terms of strain and optical performance. Raman spectroscopy and PL measurements confirmed simulation results showing higher tensile strain for beams with shorter lengths, with a maximum uniaxial strain of 1.3%. Splitting of light and heavy hole energy bands was observed by PL as the strain increases, agreeing with theoretical models. Direct-gap sharp-peak whispering-gallery modes (WGMs) were confined in 3 m disks with a maximum quality-factor of 200. Two loss mechanisms could be distinguished, red-shift of the absorption edge, and free-carrier absorption. In order to avoid these excitation-related losses, higher strain values combined with heavy n-type doping are required. A possible implementation using the same GOI platform is proposed for future work.
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43

Konieczny, Mark J. "Full-Field Strain and Temperature Measurement of Epoxy Resin PR-520 Subjected to Tensile, Compressive, and Torsional Loading at Various Strain Rates." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1556880386878411.

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44

Gilbert, Hamish. "The response of human annulus fibrosus cells to cyclic tensile strain : evidence for an altered mechanotransduction pathway with intervertebral disc degeneration." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/the-response-of-human-annulus-fibrosus-cells-to-cyclic-tensile-strain-evidence-for-an-altered-mechanotransduction-pathway-with-intervertebral-disc-degeneration(e61ab359-7b23-454e-ab4b-2236d3ea9ed9).html.

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The Intervertebral disc (IVD), comprised of two distinct regions, namely the fibrous annulus fibrosus (AF) and the gelatinous nucleus pulposus (NP), is a fibrocartilage pad located between adjoining vertebrae of the spine. The function of the IVD is to provide stability to the spine, while maintaining movement. IVD degeneration, also known as degenerative disc disease (DDD), is the process whereby the IVD tissue degrades, resulting in loss of function to the disc. Low back pain (LBP) is associated with the degeneration of the IVD, making it important to investigate the pathogenesis of DDD, as this could lead to novel therapies for the prevention and/or treatment of LBP. Mechanical stimuli (MS) are known to be important for IVD cell matrix homeostasis, with cells of the AF and NP responding to physiological forces with a trend towards increased matrix anabolism, while non-physiological forces lead to matrix catabolism. Furthermore, recent evidence suggests that IVD cells derived from degenerate tissue may have lost their ability to respond to physiological MS in the 'normal' anabolic manner, potentially leading to the progression of DDD. It is therefore important to investigate the response of IVD cells derived from both non-degenerate and degenerate tissue to MS, to ascertain whether there is a difference with degeneration. If the response is found to be altered with degeneration, then elucidation of the potentially altered mechanotransduction pathway utilised by degenerate cells could lead to the discovery of novel therapeutic targets for the treatment of DDD. To date, the majority of IVD MS studies have concentrated on the response of NP cells to hydrostatic pressure, with only a limited number of AF studies available. Thus, the first aim of this PhD was to investigate the response of human AF cells derived from non-degenerate and degenerate IVDs to the physiologically relevant mechanical stimulus of cyclic tensile strain (CTS), to ascertain whether the response (regulation of matrix protein and matrix degrading enzyme gene expression) was frequency-dependent or altered with IVD degeneration. Using an in vitro mechanical loading system (Flexcell® Tension Plus™ system, Flexcell International) capable of delivering a CTS of 10% strain, 0.33Hz or 1.0Hz for 20 minutes, the response of AF cells derived from non-degenerate IVDs was found to be frequency-dependent (reduced catabolism at 1.0Hz, with decreased MMP -3 and ADAM-TS -4 gene expression; and catabolic at 0.33Hz, with decreased types I and II collagen and increased MMP -9 gene expression). Furthermore, the response of AF cells to 1.0Hz CTS was shown to be altered with IVD degeneration, depicted by a switch from reduced catabolism (decreased MMP -3 and ADAM-TS -4) in non-degenerate AF cells, to reduced anabolism (decreased aggrecan and type I collagen gene expression) in degenerate AF cells. Subsequently, the second aim of the PhD was to attempt to elucidate the mechanotransduction pathways operating in human AF cells derived from non-degenerate and degenerate IVDs, to ascertain whether the mechanotransduction pathway was altered with IVD degeneration. An identical mechanical stimulation regime was used (1.0Hz CTS) in parallel with functional inhibitors against the cytokines interleukin (IL) -1 and -4, and the cell surface receptors, RGD-recognising integrins. Additionally, the involvement of the cytokine associated transcription factors, nuclear factor kappa beta (NFκB) and signal transducer and activator of transcription (STAT) -6, as well as the integrin-associated kinase, focal adhesion kinase (FAK) was investigated in 1.0Hz CTS-treated non-degenerate AF cells. The response to 1.0Hz CTS (reduced catabolism) of AF cells derived from non-degenerate IVDs occurred in an IL -1, IL -4 and RGD-recognising integrin-dependent manner, with FAK being phosphorylated. Of significant interest, the altered response of AF cells derived from degenerate IVDs to 1.0Hz CTS (reduced anabolism) occurred independently of either cytokine and independently of RGD-recognising integrins, suggesting an altered mechanotransduction pathway in operation and warranting further investigation.
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45

Gonzalez, Lisa. "Investigation of the shear lag coefficient for welded tension members." Thesis, Virginia Tech, 1989. http://hdl.handle.net/10919/45973.

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Shear lag is a non-uniform distribution of stress resulting when all cross sectional elements are not directly connected. This phenomenon renders the cross section only partially effective in resisting tensile loads. In this investigation, both experimental and analytical studies were conducted to ascertain the shear lag coefficients to be used in design of welded tension members by the AISC Specifications [1989].

Four types of specimens (angles, plates, channels, and tees), were tested, each with three weld configurations (longitudinal welds only, transverse welds only, and a combination of both transverse and longitudinal welds). The specimens were statically loaded in tension to failure. Experimental shear lag coefficients are presented and compared to theoretical values.


Master of Science
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46

Kersauson, Malo de. "Vers un laser germanium dopé N et contraint en tension." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112107/document.

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Dans ce travail de thèse, nous avons étudié différentes approches qui devraient permettre d’obtenir l’effet laser dans le germanium. Nous avons pu montrer expérimentalement l’influence du dopage et de la déformation sur la structure de bande du germanium, et l’adéquation avec les modèles concluants à l’existence de gain. Nous avons exploré les possibilités offertes par l’hétéro-épitaxie sur III-V pour obtenir une déformation en tension du germanium. Nous avons évalué la déformation résultante par des mesures croisées de rayons X, de diffusion Raman et de photoluminescence, et étudié l’évolution de la qualité des couches épitaxiées en fonction de la déformation et de l’épaisseur. Une nouvelle méthode de déformation du germanium, s’appuyant sur le dépôt par plasma de couches contraintes de nitrure, a été introduite et étudiée. L’effet laser a été recherché par la conception de guides ridges et microdisques déformés par ces dépôts. Plusieurs voies d’application de la déformation dans ces cavités ont été explorées à travers des simulations par éléments finis et la conception de structures de test. Cette optimisation préalable nous a permis d’observer sur les microdisques une déformation biaxiale de 1.11%. En uniaxial, nous avons pu appliquer au germanium une déformation de 1.07% et montrer expérimentalement l’importance de la direction de la déformation dans l’augmentation de la luminescence. Nous avons pu observer et mesurer un gain optique net de 80 cm⁻¹ dans des structures déformées uniaxialement à 0.8%
In this PhD work, we studied different approaches that should lead to a germanium laser. We have experimentally shown the influence of strain and doping on the germanium band structure, and the adequacy of the existing models. We explored the possibilities offered by heteroepitaxy on III-V compounds to apply stress. We investigated the resulting strain by cross-checking X-rays, Raman spectroscopy and photoluminescence measurements, and analysed the quality of the grown layers depending on strain and thickness. A new method to apply strain to the germanium, by means of plasma deposited stressed nitride layers, was introduced and studied. Lasing has been pursued by conceiving ridges and microdisks strained by this method. An optimization of the geometry was performed through finite element modeling and the production of test structures. This optimization allowed to achieve a maximum biaxial strain of 1.1%. For uniaxial strains, we observed a maximum of 1.07% and showed experimentally the importance of the crystalline orientation in the enhancement of the emission. We demonstrated a modal gain value of 80 cm⁻¹ in ridges uniaxially strained at 0.8%
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47

Owens, Anthony Taylor Tippur Hareesh V. "Development of a split Hopkinson tension bar for testing stress-strain response of particulate composites under high rates of loading." Auburn, Ala., 2007. http://repo.lib.auburn.edu/Send%2002-04-08/OWENS_ANTHONY_54.pdf.

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48

Radford, Darren D. "Mechanical and constitutive behaviour of Zr-2.5Nb pressure tube material at high rates of tensile strain." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape4/PQDD_0018/NQ52332.pdf.

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49

Radford, Darren D. (Darren Dale) Carleton University Dissertation Engineering Mechanical and Aerospace. "Mechanical and constitutive behaviour of Zr-2.5Nb pressure tube material at high rates of tensile strain." Ottawa, 2000.

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50

Iwamoto, Sohei. "Analysis of multiple cracking and interfacial debonding of the galvannealed coating layer under applied tensile strain." 京都大学 (Kyoto University), 2009. http://hdl.handle.net/2433/77968.

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Kyoto University (京都大学)
0048
新制・課程博士
博士(工学)
甲第14575号
工博第3043号
新制||工||1453(附属図書館)
26927
UT51-2009-D287
京都大学大学院工学研究科材料工学専攻
(主査)教授 落合 庄治郎, 教授 粟倉 泰弘, 准教授 奥田 浩司
学位規則第4条第1項該当
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