Damage Tolerance Studies At The Blade Root Attachment Of Aero Engines

The Stress and failure analysis of turbine components plays a vital role in the performance evaluation of an aeroengine. The turbine consists of a disc over which blades are attached mainly either by dovetail or fir-tree arrangements. Fretting damages at the contact interfaces are studied commonly during post failure through fractographic studies. Prediction of contact tractions and stresses during fretting loading cycle is a challenging task yet to be addresses, through in-situ micro-tomography, Synchrotron X-ray micro-tomography and acoustic emission techniques have been recently implemented in fretting fatigue setup, to identify crack initiation and crack growth. The lack of appropriate measurement system makes the prediction of fretting variables at contact interfaces to be totally dependent on either analytical or numerical methods. Analytical Solutions developed are applicable for limited cases of contact problems; however, as practical situations involve complex geometries, which are difficult to solve by existing analytical methods, considerable development has taken place in the numerical methods and semi-analytical methods. An attempt has been carried to Simulate quasi-static and fatigue crack growth by using 3-Dimensional finite element method extensively, for the prediction of contact traction and stresses over fretting of dovetail assembly by using commercially available FE code ANSYS and Fatigue Crack growth code ZENCRACK. The inference of this study are encouraging concerning the possibility of using ZENCRACK as an advantageous computational tool for obtaining K solutions and life estimation for a particular crack front geometries.