Numerical investigation of the fatigue crack growth path in Ti-6Al-4V alloy material

The primary objective of this numerical investigation is to simulate and foresee the crack propagation behavior in linear elastic materials subjected to mixed-mode (Mode I + Mode II) loading, with specific focus on understanding the influence of geometric discontinuities (holes) on the fatigue life and crack growth in Modified Compact Tension Specimens (MCTS). Leveraging principles from Linear Elastic Fracture Mechanics (LEFM), the study employs the Paris’ Law model to quantitatively evaluate the fatigue crack growth behavior in Ti-6Al-4V alloy specimens featuring multiple geometric configurations. The computational methodology incorporates, progressive crack growth analysis under cyclic loading conditions, fatigue life prediction based on crack length increment and cycle count, accurate calculation of Stress Intensity Factors (SIF’s) for mixed-mode conditions and fracture path trajectory simulation based on energy release rate and local stress field. Finite Element Analysis (FEA) is conducted using ANSYS, enabling precise prediction of crack propagation paths and corresponding fatigue life under constant amplitude cyclic loading. The effect of hole placement and spacing (i.e. various MCTS configurations) is systematically examined to assess their role in altering the stress concentration, crack deflection, and fatigue crack growth rate. This study provides critical insights into the design sensitivity of MCTS geometries in high-cycle fatigue environments and supports the optimization of damage-tolerant structures through advanced fracture modeling techniques.