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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 22 for “"relaxation tests"”.
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Viscoelastic characterization of collagen-GAG scaffolds
… exhibit linear viscoelastic behavior. Tension tests were performed on dry and hydrated engineered collagen-GAG scaffolds in order to develop a stress-strain curve. Strains that fell in the linear elastic region of these curves were selected and then used in stress relaxation tests that were …
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Tensile relaxation of bonded concrete overlays
… build up, cracking and even debonding. Tensile relaxation is the main mechanism of stress relief in concrete overlays. This results in less possibility of cracking and debonding. The research described in this study presents an analytical method of analysis. This method is based on tests …
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Compression testing and measurement of material properties of a double network hydrogel
… under compressive loads in cyclic compression tests and stress relaxation tests. A viscoelastic model was applied and material properties were calculated using the experimental data. The elastic modulus of these PAAm-alginate gels was found to be 35kPa, while the viscosity, [eta], was found to …
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Determinação dos parâmetros de resistência, "Creep" e de Relaxação de Tensões de uma argila mole do Rio de Janeiro
… The stress-strain curves of the triaxial tests are represented by the hyperbolic formula. The strength and stress-strain parametersare determined and compared with those of other clays. The results of triaxial tests performed on undisturbed and disturbed samples are discussed. The …
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Nonlinear Viscoelastic Behavior of Ligaments and Tendons: Models and Experiments
… Axial stress-stretch data and stress relaxation data at different axial stretches were collected by testing rat tail tendon fascicles. The experimental results demonstrated, for the first time, that the shape of the normalized axial stress relaxation curve depends on the axial stretch …
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The plastic behavior of predeformed ice crystals
… Creep, constant strain rate, and stress relaxation tests were performed as a function of stress, strain rate, temperature, and predeformation value. The response can be described in good approximation by a linear second order differential equation resulting from a combination of …
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Material Properties of the Grade 300 and Grade 270 Prestressing Strands and their Impact on the Design of Bridges
… material properties of the new Grade 300, low-relaxation prestressing strand. The purpose of this testing was to verify the advertised breaking strengths and relaxation properties of the Grade 300 strand. Additional properties, such as yield strength, modulus of elasticity, and elongation, were …
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Biaxial Mechanical Behavior of Swine Pelvic Floor Ligaments: Experiments and Modeling
… the first biaxial elastic and viscoelastic tests were performed on uterosacral and cardinal ligament complexes harvested from adult female swine. Biaxial elastic testing revealed that the ligaments undergo large strains and are anisotropic. The direction normal to the upper vagina was …
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Viscoelastic behavior of water-blown flexible polyurethane foams
… made from these foams. Three viscoelastic tests; tensile stress relaxation, compression load relaxation, and compression creep, were utilized to evaluate the behavior of these materials at constant temperature and/or relative humidity, RH. The tensile stress relaxation tests were performed …
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Viscoplastic Study of 3D Printed Carbon Fiber Composites
… be gathered from a series of tensile and stress relaxation tests. A third type of test, creep, was also performed in order to validate the model predication of creep at different temperatures and loads.</p> <p>The viscoplasticity model presented in this paper was able to get rough estimations of …
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Process-induced viscoelastic residual stress analysis of graphite/epoxy composite structures
… viscoelastic behavior, a series of stress relaxation tests was performed on fully and partially cured 3501-6 epoxy specimens. The master relaxation curves were modeled as functions of time and degree of cure in a thermorheologically complex manner. From this information, time and degree of …
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Large strain time-dependent behavior of elastomeric materials
… the state that is approached in long time stress relaxation tests; and a second network capturing the non-linear rate-dependent deviation from the equilibrium state. The time-dependence of the second network is further assumed to be governed by the reputational motion of molecules having the …
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Rate and time dependent behavior of structural adhesives
… from mechanical models can be used for creep and relaxation loading. Modifications to the constitutive equations for constant strain rate loading are proposed. Nonlinear constitutive equations are derived using a nonlinear perturbation technique in conjunction with a modified Bingham model. Using …
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An experimental study on time-dependent behaviour of reconstituted clayey soils in 1D and triaxial compression
… consists of oedometer and triaxial compression tests on compacted lightly overconsolidated natural soils (high plastic Regina clay and low plastic Calgary till) as well as on artificial soil mixtures made by mixing pure kaolinite or bentonite with crushed Opal, silt or Calgary till. Results of …
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Predicting and testing the tensile relaxation of concrete
Tensile relaxation is an important property in structural concrete members such as concrete overlays and patch repairs under sustained imposed restraint. Tensile relaxation helps in reducing tensile stresses in concrete which leads to mitigation of cracking in restrained concrete members. Normally, …
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The Thermal Stabilisation of Austenite at Sub-Zero Temperatures
… a stabilisation mechanism controlled by stress-relaxation.<br/>The kinetics of stabilisation have been studied using an electrical resistance technique in two 0.5% carbon steels containing 19% and 24% nickel, after treatments at temperatures between -100°C and -40%. In addition, the response of …
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Cheddar cheese : Its texture, chemical composition and rheological properties.
… rheological properties were measured using three tests performed on an Instron Universal Testing Machine - a compression test, a cutting test and a stress relaxation test - and, where appropriate, were reported in terms of true stress and true (Hencky) strain curves. The viscoelastic properties of …
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Linear and Nonlinear Viscoelastic Characterization of Proton Exchange Membranes and Stress Modeling for Fuel Cell Applications
… mechanical analyzer (DMA), and their stress relaxation behavior was characterized over a period of time. Hygral master curves were constructed noting hygral shift factors, followed by thermal shifts to construct a hygrothermal master curve. This process was reversed (thermal shifts followed …
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PSYCHOMETRIC PROPERTIES OF INSTRUMENTS MEASURING STRESS IN THE AGED.
This study was designed to assess the appropriateness of current standardized checklists used to measure stressful life events in a noninstitutionalized population aged 65-74 years of age. Previous studies, sampling from a younger aged population, have demonstrated a temporal association between an …
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Durability and Damage Analysis of Hybrid Multiscale Composites
… behavior of these composites using stress relaxation and creep tests was also performed for these different composites’ configurations. A phenomenological viscoplastic model was utilized for creep prediction over long periods of time utilizing shorter stress relaxation tests. The results …
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