Open Access

ARTICLE

Analysis of Local Fracture Strain and Damage Limit of Advanced High Strength Steels using Measured Displacement Fields and FEM

by N. Ma¹, K. Sato³, K. Takada⁴

1 Osaka University, Osaka, Japan.
2 JSOL Corporation, Osaka, Japan.
3 JFE Steel Corporation, Hiroshima, Japan.
4 Honda R&D Co. Ltd, Tochigi, Japan.

Computers, Materials & Continua 2015, 46(3), 195-219. https://doi.org/10.3970/cmc.2015.046.195

Abstract

The local mechanical behaviors of advanced high strength steels undergoing a very large strain from uniform plastic deformation to fracture were investigated with the aid of a measured displacement field and a measurement based FEM. As a measurement method, a digital image grid method (DIGM) was developed and the three-direction transient displacement field on uniaxial tensile test pieces was measured. Combining the measured transient displacement field with the finite element method, a measurement based FEM (M-FEM) was developed for the computation of distribution of the local strains, local stresses and ductile damage accumulation in a tensile test piece. Furthermore, the local fracture strain and damage limit of several advanced high strength steel sheets (980MPa/t1.2mm, 980MPa/t1.6mm, 1180MPa/t1.6mm) were identified by uniaxial tensile tests and the measurement based FEM. The identified damage limit of materials agreed very well compared with that measured by a conventional press test, and the validity of the measuring method and measurement based FEM was verified.

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Keywords

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