Efficient algorithmic incorporation of tension compression asymmetry into an anisotropic damage model

In order to exclude spurious failure in compression the consideration of tension compression asymmetry (TCA) in damage models is of great interest in research as well as in industry. This paper presents an efficient and unifying algorithmic procedure for the incorporation of TCA into damage models. With the presented approach the implementation effort is drastically reduced since the equations and subroutines of the model without TCA can be reused. The strategy is first introduced and illustrated for an isotropic damage model. Afterwards, the procedure is applied to a gradient-extended anisotropic damage model with a second order damage tensor recently developed by the authors. For this model studies at integration point level as well as structural examples are presented. Two different aspects are included in the presented TCA approach and are demonstrated with the results of the simulations: (i) different damage evolution in tension and compression and (ii) stiffness recovery (crack closure) under compression. Due to the utilized gradient-extended formulation, being very efficient since only one additional degree of freedom is introduced, the finite element computations are shown to deliver mesh-objective results. (C) 2019 Elsevier B.V. All rights reserved.