Investigation of Fatigue Growth Behavior of an Inclined Crack in Aluminum Alloy Plate

Abstract

In the present paper, fatigue tensile tests are carried out on a servo-hydraulic fatigue testing machine to study the whole propagation process of the inclined crack. And the scanning electron microscope is employed to observe the micromorphology of the fracture surface to further probe the crack growth rate from a microscopic point of view. Meanwhile, the finite element method has also been applied to predict the crack propagation trajectory and the fatigue life of the sample with two finite element analysis codes. The fatigue tensile tests indicate the inclined crack propagates along the direction perpendicular to the external loading and the crack growth rate increases continuously based on the micromorphology of the fracture surface. The numerical analysis results reveal the variation of the stress distribution at the crack tip as well as the crack trajectory at different extension steps. Moreover, the stress intensity factor values are discussed in detail. And the computed results, the inclined crack propagation path and fatigue life of the sample, agree well with the experimental ones, which provide certain referential significance for the prediction of the inclined crack propagation in thin plate.