Experimental Study on the Role of Hole Expansion Ratio in Enhancing Crashworthiness of Advanced High Strength Steel

To meet light weighting and safety targets, the automotive industry is increasingly using advanced high strength steel (AHSS) materials and advanced manufacturing techniques for complex body parts. To improve energy absorption of automotive body parts, various steel grades are developed by steel manufactures with variety of properties (YS, UTS, EL %, HER). Also, the formability of AHSS grades (TS > 980 MPa) is challenging due to its limited edge ductility. This study focuses on role of hole expansion ratio (HER) in energy absorption of AHSS material. In the study, different AHSS material with variety of microstructure and properties are experimented, with the aim to identify the optimum properties that can help to enhance crash worthiness of formed part. From experimentation, it is evident that hole expansion ratio plays an important role in determining edge ductility, as well as energy absorption. This study may not only help to improve crash performance but also help for light-weighting of automotive body parts.