The viscoplastic behavior of a carbon-fiber/polymer matrix composite was investigated through two different modeling efforts. The first model is phenomenological in nature and utilizes the tensile and stress relaxation experiments to predict the creep strain. The phenomenological model was constructed based on the overstress viscoplastic model. In the second model, the composite viscoplastic be...

This work is an attempt to apply conventional mechanical testing to characterize the photoinduced viscoelastic behavior of chalcogenide glasses. Creep or relaxation-recovery experiments are usually performed to characterize the delayed elastic contribution to deformation, during thermally activated flow. In this paper, relaxation-recovery is used to characterize delayed elasticity under irradia...

The thermomechanical problem involving simple shearing of a finite slab made of an isotropic and viscoplastic material is studied with the objective of finding the e&t of the strain hardening parameter, strain-rate hardening parameters, thermal softening coeflicient and thermal conductivity on the initiation and growth of adiabatic shear bands. The body is placed in a hard loading device, i.e. ...

ABSTRACT. This work is focused on the numerical implementation of thermo-viscoplastic constitutive equations in small and finite strain contexts using FEM. A length scale parameter is introduced implicitly through viscosity in order to address strain localization in the (initial) boundary value problems. The mathematical structure of the infinitesimal viscoplasticity theory is concise and simil...

Cam-Clay nonassociative plasticity exhibits both hardening and softening behaviour, depending on the loading. For many initial data the classical formulation of the quasistatic evolution problem has no smooth solution. We propose here a notion of generalized solution, based on a viscoplastic approximation. To study the limit of the viscoplastic evolutions we rescale time, in such a way that the...

This paper deals with unified elastoplastic and elastic-viscoplastic constitutive equations for metals submitted to large deformations. We present here a newly developed time integration algorithm which is an extension to the viscoplastic range of the classical radial return algorithm for plasticity. The resulting implicit algorithm is both efficient and very inexpensive. This algorithm is also...

The theoretical basis of classic geotechnical engineering stability problems is limit analyis thereom. Incremental loading finite elements and strength reduction finite elements were put forward by Zienkiewicz in 1975 and the methods are called by the authors Limit Analysis Finite Elements (abbreviation LAFE for short). It has been successfully applied to slope engineering, and used to bearing ...

In this paper a rate dependent model for unsaturated geomaterials is presented. The formulation and numerical predictions are compared with available experimental results and discussed. The constitutive laws for the description of the time-dependent mechanical behaviour of saturated and unsaturated geomaterials generalize the isotach approach to the elastoplastic strain hardening based constitu...

The spreading under surface tension and gravity of a droplet yield-stress fluid over thin film the same material is studied. converges to final equilibrium shape once driving stresses inside fall below yield stress. Scaling laws are presented for radius complemented with an asymptotic analysis shallow droplets. Moreover, numerical simulations using volume-of-fluid method regularized constitutiv...