An adaptive automatic cell generation for elasto-plastic problems has been developed which eliminates the need of user definition of the cells. These are progressively generated only on those points where plasticity occurs. Unnecessary domain computations are avoided, which leads to a gain in efficiency. The new method has been tested on examples and the accuracy of the results is in agreement ...

In this paper some analytical and numerical aspects of time-dependent models with internal variables are discussed. The focus lies on elasto/visco-plastic models of monotone type arising in the theory of inelastic behavior of materials. This class of problems includes the classical models of elasto-plasticity with hardening and viscous models of the Norton-Hoff type. We discuss the existence th...

In this acticle a semi-smooth Newton method for frictional two-body contact problems and a solution algorithm for the resulting sequence of linear systems is presented. It is based on a mixed variational formulation of the problem and a discretization by finite elements of higher-order. General friction laws depending on the normal stresses and elasto-plastic material behaviour with linear isot...

In this contribution, we deal with time-stepping schemes for geometrically nonlinear multiplicative elasto-plasto-dynamics. Thereby, the approximation in space as well as in time rely both on a Finite Element approach, providing a general framework which conceptually includes also higher-order schemes. In this context, the algorithmic conservation properties of the related integrators strongly ...

Nowadays, the use of advanced software technologies, especially symbolic and algebraic systems, object oriented techniques and automatic differentiation tools, can influence directly on how the mechanical problem and numerical model are postulated and solved, leading to cooperative problem solving in computational mechanics. Emphasis in the paper will be given to direct analyses of complex elas...

A finite element model has been developed to simulate nonlinear response of piles/drilled piers under axial loading. The nonlinear stress-strain behaviors of soils are modeled via Drucker-Prager and von Mises type plasticity. A parametric study is carried out to address the influence of various factors, such as soil friction approximation, dilatancy, effect of interface element and shear streng...

We consider control problems for the variational inequality describing a single degree of freedom elasto-plastic oscillator. We are particularly interested in finding the ”critical excitation”, i.e., the lowest energy input excitation that drives the system between the prescribed initial and final states within a given time span. This is a control problem for a state evolution described by a va...

The goal of this research is to study the performance ofmeshless approximations and their integration. Two diffuse shape functions, namely the moving least-squares and local maximum-entropy function, and a linear triangular interpolation are compared using Gaussian integration and the stabilized conforming nodal integration scheme. The shape functions and integration schemes are tested on two e...

In this study, the hydrogen transport phenomenon was numerically evaluated by using hydrogen-enhanced localized plasticity (HELP) mechanisms. Two dominant governing equations, namely, the hydrogen transport model and the elasto-plastic model, were introduced. In addition, the implicitly formulated equations of the governing equations were implemented into ABAQUS UMAT user-defined subroutines. T...