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The Scientific World Journal
Volume 2014, Article ID 260571, 8 pages
http://dx.doi.org/10.1155/2014/260571
Research Article

Rate Sensitive Continuum Damage Models and Mesh Dependence in Finite Element Analyses

Division of Material and Computational Mechanics, Department of Applied Mechanics, Chalmers University of Technology, 412 96 Gothenburg, Sweden

Received 21 January 2014; Accepted 2 September 2014; Published 3 November 2014

Academic Editor: Alfredo E. Huespe

Copyright © 2014 Goran Ljustina et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The experiences from orthogonal machining simulations show that the Johnson-Cook (JC) dynamic failure model exhibits significant element size dependence. Such mesh dependence is a direct consequence of the utilization of local damage models. The current contribution is an investigation of the extent of the possible pathological mesh dependence. A comparison of the resulting JC model behavior combined with two types of damage evolution is considered. The first damage model is the JC dynamic failure model, where the development of the “damage” does not affect the response until the critical state is reached. The second one is a continuum damage model, where the damage variable is affecting the material response continuously during the deformation. Both the plasticity and the damage models are rate dependent, and the damage evolutions for both models are defined as a postprocessing of the effective stress response. The investigation is conducted for a series of 2D shear tests utilizing different FE representations of the plane strain plate with pearlite material properties. The results show for both damage models, using realistic pearlite material parameters, that similar extent of the mesh dependence is obtained and that the possible viscous regularization effects are absent in the current investigation.