A micro-damage model for high velocity impacts using nonlocal theory

Rashid K. Abu Al-Rub, George Z. Voyiadjis, Anthony N. Palazotto

Research output: Contribution to journalConference articlepeer-review

Abstract

This paper presents a nonlocal gradient-enhanced theory coupled to viscoinelasticity. Constitutive equations for anisotropic thermo-viscodamage mechanism coupled with thermo-hypoelasto-viscoplastic deformation are presented. Explicit and implicit microstructural length scale measures, which preserve the well-posedness of the differential equations, are introduced through the use of the viscosity and gradient localization limiters. The gradient-enhanced theory that incorporates macroscale interstate variables and their high-order gradients is developed here to describe the change in the internal structure and in order to investigate the size effect of statistical inhomogeneity of the evolution-related plasticity and damage. We present within the finite element context the numerical algorithms for the integration of the present formulation of geometrically nonlinear gradient-enhanced (nonlocal) viscoinelasticity. The proposed unified integration algorithms are extensions of the classical rate-independent return mapping algorithms to the rate-dependent problems. Furthermore, a trivially incrementally objective integration scheme is established for the rate constitutive relations. A simple and direct computational algorithm is also used for calculation of the higher-order gradients. This algorithm can be implemented in the existing finite element codes without numerous modifications as compared to the current numerical approaches for integrating gradient-dependent models. Model capabilities are preliminarily illustrated for the dynamic localization of inelastic flow in adiabatic shear bands and the perforation of a 12mm thick Weldox 460E steel plates by deformable blunt projectiles at various impact speeds.

Original languageBritish English
Pages (from-to)6704-6708
Number of pages5
JournalCollection of Technical Papers - AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference
Volume10
StatePublished - 2005
Event46th AIAA/ASME/ASCE/AHS/ASC Structures, Structural Dynamics and Materials Conference - Austin, TX, United States
Duration: 18 Apr 200521 Apr 2005

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