The stress intensity factor study of an elliptical cracked shaft

The stress intensity factors of an elliptical crack front embedded with a round bar have been evaluated by collapsed singular element with detailed mesh on crack front and appropriating adjacent area. Using ansys newly developed model with sweeping capability, the mesh of the cracked shaft model can be easily built. The three-dimensional finite element analyses are then performed to calculate the stress intensity factors of elliptical crack front of a round bar subjected to tension and bending. The ratio of crack depth to shaft diameter is considered in the range between 0.1 and 0.6, and the elliptical ratio of crack area is in the range between 0.0 and 1.0. By comparing the stress intensity factors for different crack profiles with appropriated published results, the variation of stress intensity factors on the center and near edge location have been discussed. It also addresses the related change of the equivalent elliptical ratio of crack profile with respect to crack depth ratio. Based on stress intensity factor results, the three-parameter stress intensity factor relationships of the crack front are then determined by curve fitting technique.