Contact Mechanics via FEM and BEM for Multibody Dynamics Modeling

Robotic systems and their mechanism assemblies are unprecedentedly leveraged in current NASA programs for on-orbit operations and space explorations in the solar system and its other planets, and the stellar spaces beyond. These robotic systems are operating in harsh and hostile environments which can potentially damage mission critical components and jeopardize mission success. It is well-known that high-quality multibody dynamics predictions of contact interaction loads are vital to achieve the optimal robotic and mechanism structural designs with reduced weight. It is also widely recognized that the well-established predictive methodology is one of the key approaches to accurately characterize contact modeling parameters for multibody dynamics predictions. This paper focuses on deriving contact coefficient and exponent, and model cross validation of multibody dynamics contact loads via finite element nonlinear contact analysis. Such predictive approach is verified and validated by boundary element contact analysis and Hertzian contact theory. The current work also aims at addressing the development of the boundary element method, which shows evidentially superior efficiency and accuracy for contact mechanics, to model thermomechanical responses. The importance to develop a BEM-based size-dependent contact mechanics that utilizes couple-stress theory is discussed.