F2010B049
Development of an Integrated Energy Absorber with Tube Expansion Type for Frontal Crash
The light-weight and safe design of auto-body structures are most important requirements in the automotive industry in order to increase the fuel efficiency satisfying the emission-gas regulation of vehicles and to ensure the safety of passengers against the car crash. However, these demands are conflictingly difficult characteristics to be accomplished simultaneously. Therefore, many researches is studied according to replacement to high strength steel or light material, new design concepts, enhancement of efficiency of an engine and safety devices, etc.
A crash box and a front side member are typical frontal parts to absorb crash energy. A crash box is an automotive part that couples a bumper beam on a front side member. Recently, An automotive crash box becomes to be needed to have characteristics of low impact force and high energy absorption in order to reduce the repairing cost and to achieve light-weight design. However, conventional crash boxes with collapse type have high impact force by buckling and low energy absorption due to local deformation by bending. Therefore, it is necessary a crash box to satisfy performance requirements for low speed crash. A front side member is a typical stiffness part to compose engine room, and is a main part to absorb energy in high speed frontal crash. A good front side member has a crash characteristic that deformed front region absorbs much energy and rear part connected an engine and a transmission maintains the original shape. In this paper, a novel integrated frontal energy absorber is developed to satisfy demands of low and high speed crashes simultaneously in spite of light and small part. The operation principal of new integrated energy absorber is double collapse of two tubes after expansion of a tube. Since tube expansion has uniform impact force, low impact force and high energy absorption is able to be satisfied at low speed crash. As the velocity increases, a fixed tube and an expanded tube are collapsed with shape of a double walled tube at the same time. Since an expanded tube is able to have plastic strain more that 40%, high strength and elongation steel such as TWIP and stainless steel is suitable to be adopted and much crash energy can be absorbed.
This abstract is supplemented by a PDF, which can be viewed here.
Session: Passive Safety Issues