J-integral evaluation of surface cracks in round bar under mode III loadings

Abstract

Fracture mechanics approach has successfully used to characterize the existing cracks in engineering materials and structures. Tremendous number of publications on surface cracks can be found for crack behaviour which was assumed to behave linear elastic. However, lack of information on elastic-plastic crack behaviour or J-integral was demanded especially for 3D surface cracks. In this present study, semi-elliptical surface cracks embedded in a solid round bar subjected to mode III loadings are considered. Then, J-integral or h-function and limit load were determined and analyzed. In order to predict J-integral along the crack front, a mathematical model was then developed. It is found that the developed model capable to predict J-integral well. However, the predictions breakdown occurred when the elastic dominated region of cracks. © Maxwell Scientific Organization, 2014.