Damage model and implementation in nonlinear dynamic problems

Abstract

Microcracking, damage and subsequent softening in materials introduce higher levels of nonlinearity than those for materials characterized by nonlinear elastic or classical plasticity models. Hence, implementation of such advanced models that allow for the foregoing effects require special considerations in terms of the analysis of the characteristics of the model, convergence during plastic deformations, and time integration schemes that consider the nonlinearity. This paper describes a damage model, a special scheme involving drift correction and the generalized time finite element (GTFEM) scheme for time integration for dynamic analysis. The main objective is to examine the model and develop schemes that can lead to consistent and reliable predictions from computational procedures. Toward this aim, (1) the damage model is analyzed with respect to its convergence behavior with mesh refinement, (2) a special drift correct scheme is implemented for the plasticity based model, (3) the generalized time finite element method (GTFEM) is implemented in the nonlinear dynamic finite element procedure for time integration and compared with the Newmark method, and (4) the damage model, the drift correction scheme and the GTFEM are verified by solution of representative static and dynamic problems involving a material (concrete) that experiences damage and softening, including verification with respect to behavior of concrete in the laboratory.