The stress-strain relationship in shales is generally time-dependent. This concerns their long-term deformation unconventional reservoirs, and its influence on the situ stress state therein. paper presents an experimental investigation time-dependent of Longmaxi shale gas shale. A series creep experiments subject samples to long-term, multi-step triaxial compression. It found that exhibit varyi...

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...

We consider numerical approximations of a class of abstract nonlinear evolutionary systems arising in the study of quasistatic frictional contact problems for elastic-viscoplastic materials. Both spatially semi-discrete and fully discrete schemes are analyzed with the nite element method employed to discretize the spatial domain. Strong convergence of both approximations is established under mi...

We consider a class of abstract nonlinear evolution systems arising in the study of quasistatic frictionless contact problems for elastic-viscoplastic materials. The variational analysis of such systems, including existence and uniqueness results as well as some properties concerning the behavior of the solution, has been done in 12]. In this paper we consider numerical approximations of this c...

Contemporary computing packages handle a wide variety of stress analysis types, but are yet to provide an optimal way to handle certain load cases and geometries. Blades in gas turbine propulsion systems, for instance, undergo repetitive thermal and mechanical load cycles of varied shape and phasing. Complexly-shaped airfoils create non-uniform stress paths that exacerbate the problem of FEA so...

We consider the quasistatic Signorini’s contact problem with damage for elastic-viscoplastic bodies. The mechanical damage of the material, caused by excessive stress or strain, is described by a damage function whose evolution is modeled by an inclusion of parabolic type. We provide a variational formulation for the mechanical problem and sketch a proof of the existence of a uniqueweak solutio...