Numerical Simulation of Semi-Elliptical Axial Crack in Pipe Bend Using XFEM

In this work, XFEM is employed to obtain the stress intensity factors (SIFs) of a semi elliptical part through thickness axial crack. In XFEM, additional functions are employed to enrich the displacement approximation using partition of unity approach. Level set functions are approximated using higher order shape functions in the crack front elements to ensure the accurate modeling of the crack. The axial crack is placed either on the inner or the outer surface in an internally pressurized pipe bend. The SIFs are extracted from XFEM solution by domain type interaction integral approach for a wide range of geometry parameters like bend radius ratio, cross sectional radius ratio and relative crack length. The results obtained by XFEM approach are compared with those obtained by FEM. These simulations show that the orientation and type of crack in pipe bend has a significant effect on the SIF.