A new three-dimensional collision simulation algorithm, called DyMESH (Dynamic MEchanical SHell) was recently introduced. This paper presents a validation of DyMESH for vehicle vs barrier collisions. Here the application of three-dimensional force vs crush curves using the outlined methodology is shown to be effective. Nonlinear force versus crush relationships are introduced for use in DyMESH. Included are numerous DyMESH collision simulations of several types of vehicles (e.g. light and heavy passenger car and sport utility) compared directly with experimental collision test results from various types of barrier tests (e.g. full frontal, angled frontal, and offset frontal). The focus here is not on the vehicle's change in velocity, but on the acceleration vs time history. The paper shows that, while not as important for simulating velocity change, a nonlinear or piecewise linear force vs crush relationship can improve the prediction of the acceleration vs time history which is critical for simulations in which occupant dynamics are to be studied. The capability of prescribing a nonlinear force-deflection curve within DyMESH is illustrated in each case studied. The studies show the effect on vehicle acceleration as the vehicle stiffness models are altered. The simulation results agree favourably with experimental data. (A)
Abstract