Advanced High Strength Steel (AHSS) with high strength and deformation resistance
is applied to automotive components and plays an important role in protecting
passengers in the event of a crash, as well as contributing to fuel economy
improvement by reducing the weight of the car body. However, due to the low
ductility of the AHSS, there is an issue about the occurrence of fracture during
a vehicle crash. In order to cope with these problems from the early design
stage, preliminary verification is made through crash CAE analysis, but a high
level of material property definition is required for fracture prediction. To
predict fracture, many tests are required to secure the base data for parameter
calculation of a complex fracture model, and a lot of physical time is required
to verify the model. This paper aimed to semi-automate the material parameter
calculation and verification process for efficient and reliable fracture
prediction of AHSS. To this end, a user interface program was developed and its
effectiveness was verified. The GISSMO fracture model in LS − DYNA®
was used for fracture prediction, and 1.0GPa grade cold-rolled steel was
examined. The existing method of calculating GISSMO parameters may have many
error factors because it relies on the engineer's engineering judgement or the
trial and error method. To reduce these error factors, LS − OPT® and
LS − DYNA®, which are optimization tools, were linked to
calculate and optimize parameters. Uniaxial tension, simple shear, notched
tension and biaxial tension tests were conducted to evaluate the fracture
characteristics of various load paths during crash events, and a drop weight
impact test was performed for component-level verification. Finally, the
validity of the method proposed in this study was reviewed by comparing the test
and CAE analysis results.