The Influence of Contact Edge Rounding Radius on Fatigue Life of Fir Tree Tenon Joint Structure

The influence of the radius of contact edge rounding on the stress and strain distribution of a fir tree shaped tenon joint structure for a certain type of air-craft engine turbine blade was studied. The micro motion fatigue life of the tenon joint structure under different radius rounding was estimated using the equivalent stress-strain method and SWT critical plane method. After finite element analysis, the equivalent strain of the tenon joint structure decreased and the average life increased by 34% after adding rounding. The micro fatigue life of the tenon joint structure was longest when the rounding radius of the contact edge was around 0.1mm; The life prediction of SWT critical plane method is shorter than that of equivalent stress-strain method, and the error between the two is smaller when the life is shorter, within the double dispersion zone. This study can provide reference for the design of turbine blade tenon joint structure and other related work in the future.