A numerical study on fatigue design of Ti-6Al-4V total hip stem: infinite-life and damage tolerance approaches using XFEMPN-VCCT

Abstract

The present study is an original try toward establishing a simple, inclusive, and verified fatigue design methodology tied with finite element analysis (FEA) to boost the design quality before running expensive and arduous preclinical tests. First, a reliable framework is established for material selection (Ti-6Al-4V) and life estimation (an “infinite-life” viewpoint) considering the role of microstructure, processing, stress concentration, physiological environment, and manufacturing. Second, an efficiently simplified FEA framework is introduced for analysis of both “preclinical” and “clinical” situations. Third, the extended finite element method with phantom nodes coupled with virtual crack closure technique (XFEMPN-VCCT) in Abaqus is used to investigate the three-dimensional crack propagation and life estimation in the stem (a damage tolerance viewpoint). Results are then verified and validated using several analytical solutions, numerical results, and clinical data. Infinite-life results reveal that the simple methodology proposed in this paper is an efficient tool for evaluating and improving a stem design with the least loss of time and money. Damage tolerance studies show that three-dimensional XFEMPN-VCCT suffers from mesh sensitivity, dependency on the damage extrapolation parameter, and error in calculating the strain energy release rate. Additionally, it is demonstrated that the remaining useful life of a stem with a propagating long fatigue crack might be significantly shorter than the values predicted in the literature. © 2023, Springer Nature B.V.