Plastic zone analysis of SS316L and Ti6Al4V materials under mixed mode loading conditions

In present work, plastic zone size and shapes are investigated to predict failure of hip implant materials Ti6Al4V and SS316L (titanium and stainless steel, respectively). Generally, they fracture due to crack propagation in presence of wear which initiates the crack. Plastic zone analysis of SS316L and Ti6Al4V are carried out under standard fracture modes of failure that are first and mixed mode (tensile and shear loading). Crack inclination angle is one of the important parameters to simulate mixed-mode loading conditions. Analytical formulations of plastic zone analysis validated by finite element modeling based on von-Mises criteria. Further, isolines are plotted which explains the variation of plastic zone and geometry near the crack tip. Results obtained under plane strain and plane stress conditions through analytical formulations are in close relevance with FEM. Finally, it is observed that SS316L has large plastic zone which results in slower crack propagation and better life as compared to Ti6Al4V.