Material Failure Approaches for Ultra High strength Steel

The quest for predicting the material failure of ultra high strength steel introduces various approaches in simulations. BTR165 is ultra high strength steel used for safety beams in the vehicles. For the analyses of failure model, different profiles of door beams are selected. These door beams made of BTR165 are tested experimentally. Then the analyses for the similar profiles are done using LS-Dyna and compared with the test results. For BTR165, there is a very high local strain in the necking area compared to the gauge length strain. Based upon this, analyses are done to find a model that predicts the failure of the material during crash. LS-Dyna allows the analysis of the model based upon the plastic strain at failure and major in plane strain at failure strain [1]. To ensure the better material failure model for the ultra high strength steel, five different profiles of door beams are selected for the analyses. Analyses are done in LS-Dyna 970 based upon the local strain and global strain to find the best material failure model that can be compared to reality. Analyses are also done with different element sizes to find the influence of the element size. Depending upon this approach, a failure model for BTR165 is illustrated in this paper.