Relations between crack opening displacement and hoop stress in zircaloy-2 pressure tubes containing axial defects

Abstract

Analysis of the end-of-slit opening measurements in Zircaloy-2 pressure tubes containing axial through-the-wall defects as a function of hoop stress has shown that the experimental data do not conform to yielding behaviour as predicted for cracked flat plates. It is shown, however, that the results agree closely within certain limits of crack opening displacement with flat-plate behaviour if they are corrected by a non-dimensional geometrical correction as given by the equation

δ = 8σ_ya/πE(ln sec β)(1+1·6 a²/Rt)

Deviation from the equation occurs at values of δ exceeding about 0.010 in and is possibly due to gross-bulging effects.