Three-dimensional nonlinear finite element analysis of dovetail joints in aeroengine discs

Three-dimensional nonlinear finite element analysis is made of the dovetail region in aeroengine compressor disc assemblies using contact elements. The study is devoted to examining the effect of the critical geometrical features, such as flank length, flank angle, fillet radii and skew angle upon the resulting stress field. Frictional conditions at the interface between the disc and the blade are also examined. The finite element predictions were validated using three-dimensional photoelastic stress freezing results. Comparisons with the two-dimensional finite element analysis made earlier by Papanikos and Meguid (Fatigue Fract. Eng. Mater. Struct. 17 (5) (1994) 539–550) of the same geometry reveal certain inadequacies. Specifically, the earlier analysis underestimates the maximum equivalent stress along the interface by as much as 40%. This could have serious implications concerning the safety margins of the disc assembly.