Fretting wear behaviour of polymethylmethacrylate under linear motions andtorsional contact conditions

The fretting wear behaviour of PMMA against a rigid counterface has been in vestigated under various contact zone kinematic conditions. A specific devi ce has been used in order to achieve load axis spin or stationary rolling m otions in a contact between a PMMA flat and a steel ball. Wear processes un der such conditions have been investigated by means of laser profilometry a nd in-situ optical observations of the contact area during tests. Very diff erent wear patterns were produced depending on the contact kinematics. For stationary rolling conditions, the progressive accumulation and compaction of debris induced the formation of a single ripple located in the middle of the contact. Very little debris was found to be eliminated from the contac t and the resulting wear was quite low. On the other hand, little accumulat ion of debris was observed for torsional contact conditions and the wear wa s drastically enhanced. These results are analysed by considering the effec ts of contact zone kinematics on particle detachment and third body elimina tion. (C) 1999 Elsevier Science Ltd. All rights reserved.