Step-by-step Energy Absorption Method Based On Reverse Design Theory And Its Application Study

As the advantages of economical efficiency, mobility and smartness, there is a broad marketing for minibus in china. However, with the dimensional limitation for minibus, it needs to absorb the crash energy in minimal length to fit the frontal crash regulations. Generally, the frontal rails of automobile are square tubes, which absorb crash energy by collapse deformation to get the ideal effect. However, the full vehicle disposal could be influenced if the dimension of frontal rails changed, thicker wall will cause the rails deform difficultly, the mass and crash acceleration of the vehicle will also be increased. So, it's hard to get an optimal energy absorbing result just by changing frontal rail dimensions and thickening the rail wall. It's of great significance to develop a new energy absorption structure.A step by step energy absorption method based on reverse design theory is presented in this paper. In accordance with the regulation requirements, the length of energy absorbing structures for minibus is derived, and then the ideal acceleration range can be defined. By controlling the thickness of the plate and adding some strengthen plates within the rails on different position which participates in energy absorption step by step, the crash acceleration of the vehicle can be controlled. Based on this method, a step by step energy absorbing thin-walled structure is designed with the same size of the minibus rail. After a FE model of this structure is established and validated, its crashworthiness is optimized using the simulation optimization method based on surrogate model, by optimizing parameters such as wall thickness, position of strengthen plates, spotwelding spaces, preferable crashworthiness of this structure is achieved. Then we applied the optimized results and adjusted the stiffness of some related components, the frontal deformation decreased greatly and human body injury value of the occupant is also within the range the crash safety regulation required.As the study of this paper indicated, during the process of the frontal crash safety promotion for a minibus, the method presented in this paper is applicable. The energy absorbing structure designed with this method can dissipate the crash energy in shorter length and improve the full vehicle frontal crash safety effectively. Then the occupant space of this vehicle can be increased, the ride comfort can be improved and the market competitiveness of this product will also be enhanced.