The sliding friction contact frequency response function

Abstract

Abstract This paper details frequency response function (FRF) measurement and simulation for a dynamic oscillator with a sliding (Coulomb) friction contact. The oscillator is approximated physically using the friction measuring machine (FMM), a parallelogram leaf-type flexure with a sliding friction contact. The flexure-based FMM provides linear motion between a polytetrafluouroethylene pin and (lubricated) polished steel counterface. Both the input force and response velocity are measured by impact testing to determine the FRF. Numerical simulations are completed to identify the best-fit friction coefficient for three input force levels (450 N, 1000 N, and 1450 N). It is shown that: 1) the FRF magnitude increases linearly with impulse (i.e., the area under the time domain force profile); and 2) a single friction coefficient (0.113) is sufficient to describe the dynamic response for the three force levels.