Vehicle Interior Head Impact Simulations Using FCRASH

Abstract

Abstract The development of a finite element deformable featureless headform model for vehicle upper interior head impact simulations is described in this paper. The model and the head impact prediction methodology are developed using the FCRASH finite element code developed by Ford Motor Company. The model uses a visco-elastic material law which is implemented in FCRASH to simulate the vinyl skin response during impact. The constitutive parameters of the headform’s skin are calibrated through comparison of head drop simulations at various impact speeds with the corresponding tests. The predictions of the headform responses in drop tests at impact speeds of 2.68, 4.02, 5.36 and 6.71 m/s (6, 9, 12 and 15 mph) are in excellent agreement with related experiments. In addition, the head impact prediction methodology development entails validations of simulation results against the test data in both component and full vehicle system environments. Interior head impacts at various locations on A-pillar, B-pillar, header and side rail are simulated. Comparisons of the predicted results with test data in terms of peak accelerations, Head Injury Criterion (HIC) and deceleration waveforms with test results are in close agreements. Application of this CAE tool to predict head impact response during product development is essential. Attribute trade-off study, and evaluations of A-pillar trim design alternatives and material candidates and identifying countermeasures for improved head impact protection are demonstrated. It is concluded that the developed head impact simulation methodology is capable of predicting the head response and HIC calculations during headform impact with vehicle upper interior.