3-D stress intensity factors due to full autofrettage for inner radial or coplanar crack arrays and ring cracks in a spherical pressure vessel

Three dimensional, stress intensity factor for inner radial or coplanar crack arrays and ring cracks prevailing in an autofrettaged spherical pressure vessel are evaluated. The 3-D analysis is performed via the finite element method implementing a novel realistic autofrettage residual stress field incorporating the Bauschinger effect. SIFs are evaluated for arrays of radial or coplanar cracks and ring cracks of depth to wall thickness ratios of a/t=0.1-0.6, and ellipticities of a/c=0.2-1.0 in fully autofrettaged spherical vessels, ε=100%, of R_o/R_i=1.1, 1.2, and 1.7. SIFs are evaluated for radial arrays containing n=1-20 cracks, and for arrays of coplanar cracks of δ=0-0.95 densities.