Open Access

ARTICLE

Damage Analysis for Mixed Mode Crack Initiation

by Y. Wei, C.L. Chow¹, C.T. Liu²

1 Department of Mechanical Engineering, University of Michigan-Dearborn, Dearborn, MI 48128, USA
2 Air Force Research Laboratory, Edwards AFB, CA 93524-7680

Computer Modeling in Engineering & Sciences 2000, 1(4), 71-78. https://doi.org/10.3970/cmes.2000.001.523

Abstract

The paper presents a numerical simulation for mixed mode crack initiation based on the concepts of damage mechanics. A model with two scalar damage variables is introduced for characterization of damage in a material element. Then a tangent modulus tensor is derived for damage-coupled constitutive equations. A failure criterion is developed with the concept of damage accumulation not only to identify the location of damaged element where the crack initiation angle but also to determine the critical load for mixed mode fracture. The damage model developed is incorporated in a general-purpose finite element program ABAQUA through its UMAT subroutine. The finite element program is then used to perform numerical simulation for pre-cracked specimens under monotonic tensile loading. The thin plates are made of aluminum alloy and particulate composite embedded with a crack of inclined angle β = 0°, 30°, 45° and 60° for mixed mode fracture analysis. The predicted crack initiation loads and the angles of crack initiation agree well with the test results.

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