THE ROLE OF EPISTEMIC UNCERTAINTY OF CONTACT MODELS IN THE DESIGN OF MECHANICAL SYSTEMS

摘要

Impact is a wide-spread phenomenon in mechanical systems that can have a significant effect on the systems dynamics, stability, wear, and damage. The simulation of impact in complex, mechanical systems, however, is often too computationally intensive for high fidelity finite element analyses to be useful as design tools. As a result, rigid body dynamics and reduced order model simulations are often used, with the impact events modeled by ad hoc methods such as a constant coefficient of restitution or penalty stiffness. The effect of epistemic uncertainty in the choice of contact model is investigated in this paper for a representative multiple-degree of freedom mechanical system. Five contact models are considered in the analysis: a constant coefficient of restitution model, a piecewise-linear stiffness and damping (i.e. Kelvin-Voight) model, two similar elastic-plastic constitutive models, and one dissimilar elastic-plastic constitutive model. The predictions of wear and mechanical failure are assessed for each of the contact models. The ramifications of the choice of the contact model for an optimization study of the system's geometric design are also presented. These results emphasize the importance of choosing an accurate contact model when simulations are being used to drive the design of a system.