Stress Intensity Factors for a Pressurized Thick-Wall Cylinder with a Part-Through Circular Surface Flaw -Compliance Calibration and Collocation Method.

摘要

The K calibration at the deepest point of a circular surface flaw in an internally pressurized thick-walled cylinder has been determined by a compliance test as well as a three-dimensional collocation method. Compliance is defined as the change in the internal volume of a cylinder divided by an applied hydrostatic pressure instead of the usual elongation/load definition. It is shown, using the linear theory of elasticity that the derivative with respect to the crack depth of internal and external volume changes are identical. This permits the use of external strain measurements to compute the stress intensity factors. Periodic cubic splines are used to interpolate/approximate the strain data as well as to compute external volume change as a function of crack depth. The results agree very well with theoretical results obtained by the three-dimensional collocation method. (Author)