Fracture characterization of AHSS using two different experimental methods

Abstract

This paper documents two different methods to characterize the fracture strains of advanced high strength steels (AHSS) under varied stress states to construct the fracture locus. One experimental method is through the strain measurement using Digital Image Correlation, the other method being via thickness reduction measurement. Two AHSS were characterized to determine the fracture loci using the two different methods. The advantages and limitations for both methods are discussed by the analysis of the measured fracture data. Meanwhile, LS-DYNA MAT-224 (∗MAT-TABULATED-JOHNSON-COOK) material cards were determined based on the obtained fracture loci and optimized internal parameters, and the cards were applied to predict the fracture behavior of 3-point bending crash tests on the hat-section beam made of the two AHSS. Built upon the discussions on the testing and simulation results, a practice is recommended to improve the accuracy of fracture characterization and prediction.