Plane strain transient finite thermomechanical deformations of heat-conducting functionally gradient materials comprised of tungsten and nickel–iron matrix are analyzed to delineate brittle/ductile failures by the nodal release technique. Each material is modeled as strain-hardening, strain-rate-hardening and thermally-softening. Effective properties are derived by the rule of mixtures. At nomi...

experiments were carried out in which the dependence of the fractional softening on temperature, time and strain rate was determined in a 304h stainless steel. three prestrain ranges were identified pertaining to three different post-deformation softening behaviors: 1) prestraining to below the drx critical strain: strongly strain dependent softening by srx alone with softening kinetics control...

A closed-form expression for shear band spacing in strain-hardening, strain-rate-hardening and thermally softening thermoviscoplastic materials is derived by studying the stability of a homogeneous solution of equations governing its simple shearing deformations. The wavelength of the perturbation that maximizes its initial growth rate is assumed to determine the shear band spacing, Ls: The dep...

Natural materials such as nacre, bone, collagen and spider silk boast unusual combinations of stiffness, strength and toughness. Behind this performance is a staggered microstructure, which consists of stiff and elongated inclusions embedded in a softer and more deformable matrix. The micromechanics of deformation and failure associated with this microstructure are now well understood at the "u...

A split Hopkinson pressure bar is used to investigate the dynamic mechanical properties of biomedical 316L stainless steel under strain rates ranging from 1 × 10(3) s(-1) to 5 × 10(3) s(-1) and temperatures between 25°C and 800°C. The results indicate that the flow stress, work-hardening rate, strain rate sensitivity, and thermal activation energy are all significantly dependent on the strain, ...

Thermal treatments and thermo-mechanical processing routes were applied on a conventional structural steel (st37 steel: 0.12C-1.11Mn-0.16Si) for improvement of tensile properties and enhancement of work-hardening behavior. Full annealing resulted in a sheet with coarse ferrite grains and pearlite colonies arranged alternatively in distinct bands, which showed high ductility, low strength, and t...

A simple theory for glassy-polymeric mechanical response that accounts for large-scale chain relaxation is presented. It captures the crossover from perfect-plastic response to Gaussian strain hardening as the degree of polymerization N increases, without invoking entanglements. By relating hardening to interactions on the scale of monomers and chain segments, we correctly predict its magnitude...

In this paper the ratcheting behavior of carbon steel(ASTM A106B) and stainless steel(304L) elbows is studied under steady internal pressure and in-plane external moments at frequencies typical of seismic excitations. The finite element analysis with the nonlinear isotropic/kinematic (combined) hardening model has been used to evaluate ratcheting behavior of the elbows. Material parameters have...

1967 Price 8s 6d net .-summary The time hardening, life fraction and strain hardening hypotheses variously proposed to describe tiniaxisl creep deformation are considered and compared with experimental evidence. It is concluded that the strain hardening hypothesis is the most nearly correct, the experimental strains usually being within 50% of those predicted. Further, rheological and modified ...

Ahstraet-A stress resultant constitutive law in rate form is constructed for power-law hardening materials. The change of plate thickness is considered in the constitutive law. The elastic-plastic behavior of a plate element based on the stress resultant constitutive law under uniaxial combined tension and bending is determined under a limited number of nonproportional and unloading paths. The ...