The 920-mm-diameter, 1.6-mm-thick spherical pressure vessel in Figure 9.27 is a filament wound quasi-isotropic composite laminate with a single 50-mm-diameter entrance hole. The vessel material has a...

The 920-mm-diameter, 1.6-mm-thick spherical pressure vessel in Figure 9.27 is a filament wound quasi-isotropic composite laminate with a single 50-mm-diameter entrance hole. The vessel material has a mode I fracture toughness of K_Ic
= 25 MPa m^1/2. If the vessel is to contain gas at a pressure of 0.69 MPa, what is the critical length, a_c, of a single crack emanating from the edge of the hole? The Bowie Equation 9.38 may be used for this problem, and

the function f(a/R) for a biaxial stress field and a single crack of length, a, at the edge of a hole of radius, R, is tabulated below for several values of a/R.