Determination of Stress Intensities of Through-Cracks in a Plate Structure Under Uncertain Boundary Conditions by Means of Strain Gages

It is often required to determine the values of the stress-intensity factors at a tip of a given two-dimensional through-crack even when some of the boundary conditions are not exactly given. A new method is proposed for determination of this kind of stress-intensity factor by combining experimental stress-analysis techniques, fracture mechanics, and variational methods. In this paper, the stresses on the boundary of a small domain surrounding a crack tip were measured by electric resistance strain gages, and the stress-intensity factors were calculated by variational method. Sufficient accuracy was obtained. For convenience of applications, a method by means of a calculating table was proposed.