XFEM Prediction of Fatigue Crack Propagation in Ti-6Al-4V Compressor Blades under ThermoMechanical Loads

Abstract

The structural integrity of aero-engine compressor blades is critical 
for the safety and reliability of gas turbine engines. These components operate under severe conditions involving high centrifugal forces, aerodynamic pressures, and significant thermal gradients. This paper presents a numerical investigation into the fatigue crack propagation behavior of Ti-6Al-4V compressor blades subjected to complex thermo-mechanical loading conditions. By utilizing the Extended Finite Element Method (XFEM), this study decouples the mesh topology from the geometric discontinuity, allowing for the simulation of arbitrary crack paths without the need for remeshing. The research incorporates temperature-dependent material properties and a modified Paris law to account for the interplay between thermal stresses and mechanical fatigue drivers. The simulation results reveal that thermal gradients significantly alter the stress intensity factors at the crack tip, leading toaccelerated crack growth rates in specific blade regions compared to isothermal mechanical loading alone. The study identifies the leadingedge near the blade root as a critical zone for crack initiation and propagation. These findings provide valuable insights for predictive maintenance strategies and the design of damagetolerant compressor blades.