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Showing 1 to 20 of 22 for “"constant strain rate"”.
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Investigation of indentation derived creep response using constant load and constant strain rate methods
… Indentation derived creep response using constant load-hold and constant indentation strain rate methods were investigated through systematic numerical finite element analysis of conical indentation. The model system of pure tin (Sn) and Sn-based alloy with known uniaxial power-law creep …
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Viscoelastic characterization of angle ply advanced composites
… viscoelastic theory to formulate an accelerated testing procedure. To achieve this aim, forced vibration, constant strain rate and creep tests were performed at different temperature levels. Due to its practical importance, behavior below the glass transition temperature was studied. …
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Internal hydrogen-induced subcritical crack growth in stainless steels
… high temperature in a molten salt electrolyte. Constant strain rate tests and sustained load tests were performed in air at temperatures from 0 to 50$\sp\circ$C with hydrogen contents up to 41 wt. ppm. The electrical potential drop method with optical calibration was used to monitor the crack …
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The dynamic properties of concentrated charge stabilized suspensions
… properties and flow behaviors of concentrated charge stabilized suspensions are investigated in this dissertation. Monodispersed polystyrene particles with diameters ranging from 35 nm to 250 nm are used. Suspensions with volume fractions ranged from 0.10-0.62 are examined. Equilibrium …
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Rate and time dependent behavior of structural adhesives
… of describing changes in material behavior with strain rate are derived from various theoretical approaches. It is shown that certain unique relationships exist between these approaches. It is also shown that the constitutive equation derived from mechanical models can be used for creep and …
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Investigating Dislocation Behavior in High Entropy Alloys Using Atomistic Simulations
High-entropy alloy (HEA) is a new alloying strategies involving multi-principal elements in near equiatomic proportions.[39, 11, 37, 19, 41, 13] To fully understand and tune the mechanical properties and crystal plasticity of the alloys, it is necessary to investigate the dislocation behavior[15]. …
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Reliability evaluation of stacked die BGA assemblies under mechanical bending loads
… were quantified in terms of PCB flexural strain and strain rate. The experimental data from cyclic bending tests at three strain amplitudes with a constant strain rate have been used to determine the effect of strain amplitudes on cycles to failure. The experimental data from cyclic …
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Extensional rheology of bread dough
… approaches uniform uni-axial extension flow at a constant strain rate over a large portion of the experiment, thereby allowing us to directly probe the transient material function characterizing the behavior of dough in extension. The large dynamic range of this Rheometer permitted us to …
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The strain rate dependent mechanical properties and modelling of bovine cortical bone in compression
… Hopkinson bar experiments resulted in a specimen strain rate that decreases beyond reaching a maximum value at the rise time. The variation in dynamic strain rate was rectified by shaping the Hopkinson bar input pulse with a reusable, conical striker bar. The hypothesis investigated was that a …
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The influence of loading rate on excess pore pressures in triaxial tests
… in triaxial tests and with selection of rates of loading in routine tests to avoid errors due to incomplete drainage or non-uniform pore pressures in fine grained soils. The work consisted of a combination of laboratory tests in which pore pressures were measured within triaxial samples, …
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The plastic behavior of predeformed ice crystals
… a predeformation value in an attempt to maintain constant dislocation densities. 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 …
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The Influence of Substructure and Dislocation Mobility on the Creep Properties of Some Single Phase Metals
… show large variations in the form of their strain-time curves and in the stress dependence of the strain rate. At present, it is not possible to predict theoretically the mechanical responses of a given alloy.</p> <p>This thesis is concerned with the deformation of pure copper, copper-5 wt.% …
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Rheological measures of the fracture toughness of hydrogels
… Notched polyacrylamide hydrogels underwent constant strain rate tests on a rheometer to fracture the samples. Tensile tests were performed on notched samples as a baseline for comparison. Both tests used hydrogels with varying crosslinker concentration. Rheology tests were performed with …
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An experimental investigation into the anisotropic behaviour of bovine femoral cortical bone
… the behaviour of cortical bone, knowledge of the strain rate dependent behaviour is required. Many authors have investigated these properties, however, the literature appears to be ambiguous and incomplete, with little focus being placed upon the intermediate strain rate regime (1s⁻¹ to 100s⁻¹). …
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An experimental investigation of interspecies variation in mechanical properties of cortical bone
… the relationship of material properties to strain rate within each species. This information is valuable for use in modelling. Testing was performed quasistatically and at the high end of the intermediate strain rate regime. These higher rate tests were performed on a modified Split …
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Creep Behavior Of Thin Laminates Of Iron-Cobalt Alloys For Use In Switched Reluctance Motors And Generators
… magnetic bearings as well as an aircraft Integrated Power Unit and an Internal Starter/Generator for main propulsion engines. These developments are the driving force behind a new emphasis on high temperature, high strength magnetic materials for power applications. Analytical work, utilizing …
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Mechanical characterization of alloy 709 stainless steel after high temperature aging for application in advanced reactors
… studied for future development. They will operate at higher temperatures and have higher neutron fluxes and thus require the use of novel materials. These materials will need to withstand an extreme environment, including corrosion from liquid sodium. Alloy 709 is a derivative of NF709, a high …
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Multiscale characterization of mechanochemical reactions in mechanophore-crosslinked polymers under shear loading
Inspired by mechanotransduction, new strategies are employed to impart productive mechanochemical response to polymeric materials. These mechanoresponsive materials possess the ability to respond to an applied global force through a local chemical reaction. In synthetic polymers, mechanochemical …
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A multiscale study on the origins of the Portevin-Le Chatelier effect in polycrystalline nickel-based superalloys
Various engineering alloys display load drops and strain localisation during constant strain rate tensile testing, termed the Portevin-Le Chatelier (PLC) effect. This includes nickel-based superalloys, between approximately 200 °C and 600 °C. The PLC effect is widely attributed to Dynamic Strain …
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A model treating tensile deformation of semi-crystalline polymers
… device, we always measured true stress-true strain dependencies for constant strain rates. From the true stress-true strain curves, it is obvious that after a short range a strain softening occurs, followed by a hardening at large deformations. The true stress-strain dependencies clearly …
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