Parametric Study of Fretting Fatigue in Blade Disc Interface of a Fir-Tree Joint of Inconel 718 Super-Alloy

Fretting fatigue at the turbine blade and disc joints is a significant cause of failure in aviation engines. This paper focuses on the parametric study of fretting fatigue of the Inconel 718 super-alloy material on blade root joints. Finite Element analysis using the L27-orthogonal array is used to find out the deformation, stresses and contact behaviour by changing the disc speed, flank length, fillet radius, and flank angle at three levels. The parameters are very influential over the life of the joint. Also, using Mini Tab software, Taguchi analysis is performed to find the level of impact of each parameter. The results indicate that the trial, comprising 10,000 rpm of disc speed, 50/50° of flange angle, a frictional coefficient of 0.2, 2.75 mm of flange length, and 0.75/0.75 mm of fillet radius, results in minimized values (54 MPa of shear stress, 108 MPa of max principal stress, and displacement of 0.0125 mm) of fretting responses and structural integrity of the FIR joint with focusing the contact areas.