M C. Shen, Stephen M. Hsu, John A. Tesk, A Christou
An accelerated wear test pro-cedure has been developed for wear screening of ultra-high molecular weight polyethylene (UHMWPE) using a new wear tester. Results showed that the test procedure was able to discriminate known wear level samples within seven days. Worn surface texture and wear debris shape were similar to those from retrieval studies. The test procedure used a Paul-type load curve (two peaks of differ-ent magnitude) in each sliding cycle. The test was accelerated by using a periodic load spike which was designed not to change the dominant wear mechanism. For this type of loading, since the load varies with time, the effect of load on wear cannot be easily determined. Many simulation tests including joint simulators use similar load curves. Current practice is to compare mass loss of different materials at the same cycle count. This assumes that the load cycles are completely uniform throughout the test and wear and creep compensation are equal each time for different materials. For the test procedure that uses load spikes, the issue is more complicated. Therefore, a careful analysis of load history for such a test was conducted to examine the effect of load and load spikes on wear.