Abstract
Since small punch tests utilize small specimens that can be fabricated from retrieved components of artificial joints, it is useful method to evaluate in-vivo deterioration of mechanical properties of ultra-high molecular weight polyethylene (UHMWPE) used as bearing materials of artificial joints. However, standardized method, which requires strict dimensional accuracy of specimens, is not easy to perform. We have developed a modified small punch test, applicable to specimens with wider dimensional range, by the use of thickness gauges as spacers. In this study, tensile tests, compression tests, micro hardness tests and modified small punch tests were carried out, using three UHMWPE materials. Similar results were obtained from all tests, and usefulness of the modified small punch tests was confirmed.
