Weight Reduction Study on BIW by Using Boron Alloyed Hot Stamping Solution of Front Frame Rail Instead Conventional HSS or AHSS Applications

Abstract

With the increase of the performance requirements and homologative restrictions the correct way of choosing the right material on the related area is an inevitable manner for weight reduction of the vehicles. A hot stamped front frame rail which have roughly same performance with conventional cold stamped one was designed by using tailor welded and patch reinforcement. The part was optimized with full sized frontal crash (EUNCAP), full sized rear crash (Trias33) and fatigue simulations. Critic interferences-accelerations into the passenger cabin was considered for acceptance criteria of frontal crash, deformations on fuel system for acceptance criteria of rear crash and plastic deformations on the part, especially suspension fixing points, for acceptance criteria of fatigue test. At the end of all optimization the thicknesses of the system was designed as; first tailor welded part: 1.2mm, second tailor welded part:2.5mm and patch reinforcement: 1mm. Also some design critics (such as laser cut holes and trims, seal and barrier application for eliminating water infiltration into the bare surfaces of the hot stamped part) was clarified to guarantee the performance of the part during lifecycle of the vehicle. With final condition new hot stamped system was weighted 5 kg and gained a 2 kg weight reduction.

Keywords

• Front Frame Rail,Hot Stamping,Boron Alloyed Steel,Body Light Weighting,Frontal Crash,Suspension Fixing