An elastic-plastic model was developed to describe the deformation and permeability of fractured rocks under confining pressure. Elastic and elastic-plastic contact models were used in the model to analyze the deformations of a representative element containing a single fracture under various confining pressures. The present work utilized elements from contact mechanics and viscous flows to der...

Purely elastic, partially and fully plastic stress states in a thick-walled spherical pressure vessel with an inner functionally graded material (FG) coating subjected to internal and external pressures are developed analytically in this paper. The modulus of elasticity and the uniaxial yield limit of the FG coating layer are considered to vary nonlinearly through the thickness. Using Tresca’s ...

This paper presents a direct substructuring method to reduce the computing time of implicit simulations of single point incremental forming (SPIF). Substructuring is used to divide the finite element (FE) mesh into several non-overlapping parts. Based on the hypothesis that plastic deformation is localized, the substructures are categorized into two groups: the plastic—nonlinear—substructures a...

A new monolithic solution scheme for thermo-elasto-plasticity and thermo-elasto-plastic frictional contact with finite deformations and finite strains is presented. A key feature is the reformulation of all involved inequality constraints, namely those of Hill’s orthotropic yield criterion as well as the normal and tangential contact constraints, in terms of non-smooth nonlinear complementarity...

This paper presents nonlinear finite element (FE) models to predict time- and temperature-dependent responses of shape memory polymer (SMP) foams in the large deformation regime. For first time, an A SMP foam constitutive model is implemented ABAQUS FE package with aid a VUMAT subroutine thermo-visco-plastic behaviors. phenomenological reformulated adopting multiplicative decomposition gradient...

We consider rate-independent crystal plasticity with constrained elasticity, and state the variational formulation of the incremental problem. For generic boundary data, even the first time increment does not admit a smooth solution, and fine structures are formed. By using the tools of quasiconvexity, we obtain an explicit relaxation of the first incremental problem for the case of a single sl...

The development of yielded or failure zone due to an engineering construction is a subject of study in different disciplines. In Petroleum engineering, depletion from and injection of gas into a porous rock can cause development of a yield zone around the reservoir. Studying this phenomenon requires elasto-plastic analysis of geomaterial, in this case the porous rocks. In this study, which is a...

Elastic-plastic strains at points relevant for structural failures are usually approximated using formulas based on the stresses determined by elasticity theory. For this purpose, Neuber approximation is a common method to estimate local elastic-plastic in notch root, although currently only approved homogeneous components. surfacehardened notched components, these need be modified cover two po...

Numerical simulations of crack initiation which use a cohesive zone law to model a weak interface in the solid are often limited by the occurrence of an elastic snap-back instability. At the point of instability, quasi-static finite element computations are unable to converge to an equilibrium solution, which usually terminates the calculation and makes it impossible to follow the postinstabili...