Dynamics of Mechanical System Involving Conformal and Non-conformal Contact

Effective prediction of mechanical system response containing rough surface contact requires a multi-scale modeling approach. A mechanical system model may involve a Finite Element (FE) or Lumped Parameter (LP) method. In either case the model must be capable of accounting for at least two scales. The macro-scale behavior, including metric or sub-metric, such as centimeter and millimeter scales, and micron-scale accounting for the surface roughness effects must be included simultaneously. It is the objective of this research to facilitate the multi-scale modeling of mechanical system containing rough surface contact, by developing approximate equation for contact of rough surfaces and demonstrating the inclusion of the approximate equations in FE and LP models of mechanical systems. The Approximate equations for conformal and non-conformal rough surfaces in contact are derived. The approximate equations constitute contact force-displacement equations based on statistical account of interaction between rough surfaces. The force-displacement relations are implemented in an FE model of a circular washer in a bolted joint, including the surface roughness effects. The equations also serve to account for the effect of roughness in the vibration interaction of a wavy surface with a nominally flat surface