Crack initiation processes in acrylic bone cement

Abstract

A major constraint in improving the understandingof the micromechanics of the fatigue failure processand, hence, in optimizing bone cement performance isfound in the uncertainties associated with monitoring theevolution of the internal defects that are believed to dominate in vivo failure. The present study aimed to synthesize high resolution imaging with complementary damage monitoring/detection techniques. As a result, evidence of the chronology of failure has been obtained. The earliest stages of crack initiation have been captured and it is proposed that, in the presence of a pore, crack initiation may occur away from the pore due to the combined influence of pore morphology and the presence of defects within regions of stress concentration. Furthermore, experimental evidence shows that large agglomerations of BaSO4 are subject to microcracking during fatigue, although in the majority of cases, these are not the primary cause of failure.It is proposed that cracks may then remain containedwithin the agglomerations because of the clamping effectof the matrix during volumetric shrinkage upon curing