EFFECTS OF FREQUENCY ON THE FRETTING CONDITIONS IN A CONTACT BETWEEN PMMA AND A RIGID COUNTERFACE

The effects of frequency on the fretting conditions in a glass/PMMA co ntact have been investigated using experimental analysis and numerical simulations. For partial slip conditions, the changes in the shape of the fretting cycles giving the tangential load as a function of the i mposed displacement have been interpreted on the basis of changes in t he dynamic modulus of the PMMA as a function of frequency. Using the n umerical simulations, the values of the PMMA's modulus at the various frequencies were determined from the analysis of the fretting cycles. For gross slip conditions, the emphasis was placed on the determinatio n of the range of velocity associated with stick-slip processes. This information has been summarized in a fretting map giving the initial f retting condition as a function of normal load, displacement amplitude , and frequency.