Crash Performance Evaluation of Hydro-formed DP-steel Tubes Considering Welding Heat Effects, Formability and Spring-back

In order to numerically evaluate hydro‐formed DP‐steel tubes on crash performance considering welding heat effects, finite element simulations of crash behavior were performed for hydro‐formed tubes with and without heat treatment effects. Also, finite element simulations were performed for the sequential procedures of bending and hydro‐forming of tubes in order to design process parameters, particularly for the boost condition and axial feeding, considering formability and spring‐back. Effects of the material property including strain‐rate sensitivity on formability as well as spring‐back were also considered. The mechanical properties of the metal active gas (MAG) weld zone and the heat affected zone (HAZ) were obtained utilizing the continuous indentation method in this work.