Enhanced Light Weight Frontal Crash Box Design for Low Speed and Insurance Tests 2013-26-0023

Single body architecture designed for various global markets and subjected to varied load cases is a challenge for Body in White (BIW) engineers. Optimization of structural design to meet regulatory, insurance and assessment requirements is an iterative and time consuming task. With focus on reduction of vehicle's damageability and ease of repairability Original Equipment Manufactures (OEM), insurance companies and Research Council for Automobile Repairs (RCAR) [1] are striving for better designs. A space constraint crash box structure installed behind the bumper plays a significant role in absorption of energy, before transmitting to longitudinal rails.

In this study, crashworthiness of a multipurpose crash box for a hatch segment vehicle is presented with the various design of experiments conducted with a focus on light weighting, cost and ease of manufacturing. Possible cross sectional shapes that connect to common platform crash rails were tested with numerical simulations to obtain the energy absorption capacity and the mean load. In case of the simple axial crush, a section with maximum effective width within the ridge lines showed higher mean load and energy absorption without damaging the longitudinal members. Major constraint was to restraint the crash box tower from rapid time bound buckling and collapsing with an allowable intrusion for reduction of damageability. The simplified vehicle model was analyzed for an effective and reliable design method of a crash box, comparing the performance of a full car model and a single crash box model. Further to keep costs low for both domestic and export requirements, sectional modulus was optimized to a single design.