The study on the prediction of fatigue crack propagating direction under the mixed mode : In the condition of both static load and repeated load are existed where each direction is different

Abstract

It is wellknown fact that metal fatigue crack propagates normal to the direction of maximum principal stress under the multi-axial stress condition. But the fatigue crack growth direction is not clear when the near-cracktip principal stress directions of the repeated component is different from that of the constant component. Axial-shear fatigue crack growth tests with mild steel pipe specimens have been carried out to measure the direction of fatigue crack growths. As a result, it is found that the fatigue crack growth direction is influenced by the repeated component of the stress intensity factor.