Numerical analysis of fatigue crack growth in hip replacement implant

Abstract

Total hip replacement implants are a substitution of a diseased hip joint and require complete removal in order to restore hip joint functionality. Everyday physical activities produce dynamic load which is exerted onto joint surfaces. Under stated conditions, fatigue represents the most probable mechanism of implant failure. The aim of this paper is to observe structural behaviour from fatigue crack initiation to inevitable structural failure on a selected total hip replacement implant. Tendency to fatigue and its growth besides chosen material highly depends on structural geometry. Locations with the highest stress concentration are the most common place for crack initiation. Observing locations for numerical analysis are sharp edges on the neck area of selected total hip replacement implant. Applied load for this testing is equal to the maximal exerted load on a hip joint. Boundary conditions substitute the bone-implant contact. Numerical analysis is performed in Abaqus software extension-Morfeo, suitable for XFEM analysis. XFEM generates the mesh on a structure and with each new step in crack growth distributes nods evenly around the crack. Observation of crack growth shows how geometry on a specified total hip replacement implant affects the structural life of a component.