Vehicle crashworthiness and occupant protection in frontal impact by Fe analysis - An integrated approach

This paper provides an overview of Finite Element (FE) analysis of motor vehicle crashworthiness and occupant protection technology for frontal crash simulation. Particular attention is devoted to the development of an integrated FE model combining the vehicle structure, interior components, dummy and air bag in one model. The model was developed to simulate head-on crash into a rigid barrier from an initial velocity of 13.4 m/s (30 m.p.h.). In this model, similar to the test, a normally seated dummy is restrained only by the deploying air bag and knee bolster. The predicted vehicle velocity-time response agreed with available experimental data from one prototype test. The model was subsequently exercised to simulate the National Highway Traffic Safety Administration's (NHTSA) New Car Assessment Program (NCAP) test. In this simulation, the vehicle speed was increased to 15.6 m/s (35 m.p.h.) and the dummy was restrained by a three-point manual lap/shoulder belt, in addition to the air bag and knee bolster. Two additional simulations were conducted with the base model: impact into a 50% offset rigid barrier; impact into a rigid pole. Vehicle deformations and dummy kinematics are presented and discussed. The information presented in this paper should be viewed as preliminary simulation results of a very complex nonlinear mechanics problem by FE analysis where several approximations and assumptions were introduced. These generally influence the accuracy of the analysis predictions, especially for the occupant response. Also, no attempt was made to validate/correlate the model response with test data.