Plastic hinge approach to vehicle crash simulation

This paper presents a computer-based method for formulation and efficient solution of nonlinear, constrained differential equations of motion for spatial dynamic analysis of mechanical systems and its application to vehicle crash simulations. The program can be used to analyze plastic deformations of structures by employing a plastic hinge concept. A structure is divided into several components connected by plastic hinges. A plastic hinge is modeled by a joint-spring combination to represent the structural characteristics. The spring characteristics, which are obtained from experimental results, need to be modified to account for the elastic effects and to compensate for the element length difference between experiment and simulation. Dynamic correction factors are incorporated into the spring characteristics to account for the strain rate effects in the simulation. The plastic hinge technique is applied to a torque box crash event. It is found that the program, with the plastic hinge concept, provides relatively accurate results for the crash simulation, subject to availability of the elasto-plastic response characteristics and the dynamic correction factors for structural components.