Mixed Mode (I/II/III) Stress Intensity Factors in Gas Turbine Blade Considering 3D Semi-elliptical Crack

Regardless of the initiation or propagation procedure of crack in a gas turbine blade, the precise expectation of the fracture behavior, such as mixed-mode Stress Intensity Factors (SIF), plays a significant role in acquiring its operational life. Therefore, multilateral three-dimensional fracture solutions are required, including real-based mixed-mode loading (I/II/III) conditions and geometrical considerations. In this study, three-dimensional semi-elliptical crack in a gas turbine blade with various geometrical parameters and inclination angles under mixed-mode loading (I/II/III) conditions were investigated based on the employing finite element techniques and analytical procedure. In this context, the semi-elliptical crack has been considered in the critical zone of the rotating blade to achieve the effect of crack aspect ratio, rotational velocity, crack location, and mechanical properties. Fluid Solid Interaction (FSI) analysis was also performed in addition to solid functional enriched elements. Structural simulation is done at the speed of 83.776 m/s based on CFD simulation. The results indicated that Al Alloys blade shows a profitable resistance in crack propagation. Moreover, as the crack domain is near the location of x/c= 0.25 and 1.9 of crack front, the mode II SIF will be independent of rotational velocity and the blades' mechanical properties. Similarly, for the location of x/c= 1.1 in crack front, the mode III SIF is independent of rotational velocity and blades' mechanical properties.