Development of J-Integral Prediction Model for Surface Cracks in Round Bars under Combined Loadings

Abstract

Solid cylindrical bars have tremendous applications in mechanical engineering. However due to several factors such as corrosion, material and design defects, mechanical failure is unavoidable. In the present of mechanical loadings, the crack initiated at such defects and growth. Therefore, this work focuses on a numerical simulation to analyze the behavior of the surface cracks under combined mode-I loadings. Different crack aspect ratios, a/b and relative crack depth, a/D are used and the plastic stress/strain is assumed to follow the Ramberg-Osgood relation. Then, the limit loads were combined with a reference stress method to develop a mathematical model to predict J-integral along the crack front. Referring to the results, the J-integral can be predicted along the crack fronts. However, the capabilities to predict J-integral are reduced when a/b and a/D is increased.