A component-oriented material design to improve crashworthiness of safety-relevant car body structures made out of lean medium manganese steel

Abstract

Lightweight design is a key challenge to further reduce the worldwide greenhouse gas emissions. To be able to design lightweight concepts in a fast-changing environment, a stronger interlinking between engineering disciplines is required. Therefore, the generic and extendable method of component-oriented material design is postulated. In this method, not only the standardized material properties are considered during the development process, but rather the material properties tailored to the application (e.g., stress-state-dependent strain variable) and the component performance (e.g., energy absorption capacity) are formulated based on simulations as target variables within the material design process. The developed method’s potential was demon­strated for a lean medium manganese steel (MMnS) on the example of a b-pillar subjected to quasi-static loading in a side impact test. The results show that the designed MMnS exhibits better ductility properties (εkrit = 0,52) compared to the reference material 22MnB5 (εkrit = 0,17). The strength (Rp0.2 = 1049 MPa, Rm = 1404 MPa) is at similar level to that of the reference material. Subsequently, from the concluding numerical evaluation of the component performance, it is evident that the energy absorption potential of the b-pillar consisting of the developed steel could be significantly increased compared to the reference material.

Keywords

• Medium manganese steel
• quenching and partitioning
• lightweight design
• component assessment
• material design