Stress Intensity Factors for a Radially Multicracked Partially Autofrettaged Pressurized Thick-Walled Cylinder

Mode I stress intensity factors for crack arrays of up to 1024 equal radial cracks originating at the inner surface of a partially autofrettaged, pressurized thick-walled cylinder are evaluated. Both stress intensity factors i.e., K_Ip due to the pressurization, and the negative K_IA due to the compressive residual stresses, are calculated for numerous crack arrays (n = 2–1024), a wide range of nondimensional crack lengths (1/a = 0.005–0.625), and various levels of autofrettage (ε = 30, 60, 100 percent) via the finite element method. The obtained results emphasize the notable significance of the number of cracks in the array, as well as the importance of the level of autofrettage, on the stress intensity factor prevailing at the tip of these cracks. The sensitivity of the favorable effect of the overstrain in slowing down fatigue crack growth to any decrease in the level of autofreggate is also discussed.