Methodology for Simulating Roadwheel Impact to a Vehicle and Determining an Equivalent Static Load

A methodology is presented for simulating roadwheel impact to a vehicle by means of modal transient analysis and for calculating an equivalent static load. A simplified finite element model of a tracked vehicle was developed for applying this approach. Roadwheel impact was simulated as a rapidly accelerated enforced velocity applied to one corner of the vehicle which was initially airborne with zero relative velocity at all points. The response of the vehicle was dictated by its own stiffness and inertia (modal) properties and the impact velocity. Selected transient stresses, displacements, and accelerations were monitored. It was determined that application of a static force equivalent to 2.5 g would yield stresses near the load point equal to the peak transient stresses obtained for the simulated roadwheel impact. Equivalent static acceleration was found to be significantly less than the peak transient value.