Stress intensity factors for cracks emanating from a pin-loaded lug. 13; 13;

Stress intensity factors (S.I.F.s) for a single radial through crack and for two diametrical through cracks originating from a pin-loaded lug are estimated. Numerical as well as experimental methods are used to obtain these S.I.F.s. Finite Element Analysis (FEA) is used to compute the S.I.F. numerically. In the experimental method, fatigue crack growth tests are conducted to derive the S.I.F. In the F.E. approach, the two dimensional idealization of the lug is modeled with 4 node quadrilateral elements. The stress intensity factor is obtained using modified virtual crack closure integral (MVCCI) technique to post process the FEA data. Nodal forces and displacements in the elements surrounding the crack tip are used to estimate strain energy release rate from which S.I.F. is estimated. In the experimental method, crack growth rate (da/dN) versus stress intensity factor range (DeltaK) correlation data is generated in a single edge notch tension (SENT) specimen of the same thickness (as that of the lug). This data is generated at stress ratio R=0.7 to eliminate the influence of crack closure. In the lug specimen da/dN versus crack length 'a' data is generated at R=0.7. This growth rate is converted to ?K data by referring to da/dN about ?K data of SENT coupon. S.I.F.s derived from these techniques are critically examined