We study the spatially uniform case of the problem of quasistatic evolution in small strain nonassociative elastoplasticity (Cam-Clay model). Through the introdution of a viscous approximation, the problem reduces to determine the limit behavior of the solutions of a singularly perturbed system of ODE’s in a finite dimensional Banach space. Depending on the sign of two explicit scalar indicator...

We systematically investigate the incremental response of various equilibrium states of dense 2D model granular materials, along the biaxial compression path (σ11 < σ22, σ12 = 0). Stress increments are applied in arbitrary directions in 3dimensional stress space (σ11,σ22,σ12). In states with stable contact networks we compute the stiffness matrix and the elastic moduli, and separate elastic and...

P.L. Lions's work on the Schwarz alternating method for convex minimization problems is generalized to a certain non-smooth situation where the non-diierentiable part of the functionals is additive and independent with respect to the decomposition. Such functionals arise naturally in plasticity where the material law is a variational inequality formulated in L 2 ((). The application to plastici...

We study the time evolution in elastoplasticity within the rate-independent framework of generalized standard materials. Our particular interest is the formation and the evolution of microstructure. Providing models where existence proofs are possible is a challenging task since the presence of microstructure comes along with a lack of convexity and, hence, compactness arguments cannot be appli...

We explain an interface for the implementation of rate-independent elastoplasticity which separates the pointwise evaluation of the elastoplastic material law and the global solution of the momentum balance equation. The elastoplastic problem is discretized in time by diagonally implicit Runge-Kutta methods and every time step is solved with a Newton iteration. For the discretization in space t...

A shape design sensitivity analysis (DSA) and optimization of structural transient dynamics are proposed for the finite deformation elastoplastic materials under impact with a rigid surface. A shape variation of the structure is considered using the material derivative approach in continuum mechanics. Hyperelasticitybased multiplicatively decomposed elastoplasticity is used for the constitutive...