Ply-Level Failure Analysis of Thick-Section Composite Structures Based on "Smeared" Finite Element Results

Abstract

Conventional failure criteria for laminated composite materials require stresses and strains at the ply level. However, finite element analysis of practical thick-section composite structures is often based on equivalent homogeneous ("smeared" or effective) material models, which predict only laminate-averaged stresses and strains. This paper describes a post-processor to the ABAQUS general-purpose finite element code that performs ply-level failure analysis of a thick-section laminated composite structure given the results of a smeared ABAQUS analysis. The program, called ABAFAIL, provides ABAQUS users with an automated tool for composite first-ply failure analysis and produces thorough results that are easily interpreted. The ply-level stresses and strains required for failure analysis are extracted from the effective quantities at each node in the finite element model via a 3-D lamination theory. The failure criteria currently incorporated in ABAFAIL are Maximum Stress, Maximum Strain, Tsai-Hill, Tsai-Wu, and a modified version of Hashin's theory; other criteria can be easily added. Printed output includes failure indices and extrapolated failure loads. In addition, files may be obtained which are suitable for PATRAN visualization of failure index data.

Keywords

thick-section composites 3-D finite element analysis equivalent continuum modeling composite failure analysis

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