A fatigue damage model for the cement-bone interface.
Loss of fixation at the cement-bone interface can contribute to clinical loosening of cemented total hip replacements. In this study, the fatigue damage response was determined for cement-bone constructs subjected to shear fatigue loading. A typical three-phase fatigue response was observed with substantial early damage, followed by a long constant damage rate region and a final abrupt increase in damage to fracture. All of the damage resulted from creep (permanent) deformation during fatigue loading and there was no loss in cyclic stiffness. Using a Von Mises equivalent stress/strain concept, a general damage model was developed to describe the fatigue creep response of the cement-bone interface under either shear or tensile fatigue loading. Time to failure was highly correlated (r2=0.971) with equivalent creep strain rate and moderately related (r2=0.428) with equivalent initial strain for the two loading regimes. The equivalent creep strain at failure (0.052+/-0.018) was found to be independent of the applied equivalent stress. A combination of the creep damage model (to describe the damage process) with a constant final equivalent strain (as a failure criteria) could be used to assess the cement-bone failure response of cemented implant systems.
Kim
Do-Gyoon
DG
Department of Orthopaedic Surgery, Institute for Human Performance, SUNY Upstate Medical University, Syracuse, NY 13210, USA. kim@bjc.hfh.edu
Miller
Mark A
MA
Mann
Kenneth A
KA
D001843:Bone Cements; D001842:Bone and Bones / Q000502:physiology*; D006622:Hip Prosthesis; D006801:Humans; D008422:Materials Testing; D008954:Models, Biological; D011475:Prosthesis Failure; D033081:Shear Strength; D013314:Stress, Mechanical; D013718:Tensile Strength
D001843:Bone Cements