Papers by Keyword: Crack Growth Direction

Abstract: The finite element software ANSYS was employed to create a finite element model of the cracked wing beam integrated structure, and the stress field of the crack tip was got by the material nonlinearity (elastic-plastic) analysis method. Based on the maximum tensile stress theory criteria, the crack deflection angle was obtained. The crack deflection angles with different geometry parameters (crack length, wed thickness, the height-thickness ratio of the stringer, cross-sectional area, and the location of the stringer) of the wing beam integrated structure were calculated and compared with each other. So the influences of the geometry parameters of the wing beam integrated structure on the crack deflection were studied. The crack deflection angles obtained in elastic analyzing and elastic-plastic analyzing were compared to investigate the effects of the material property on the crack deflection angle.

Abstract: The stress field of an interfacial crack in non-homogeneous materials is computed using the semi-analytical method of arbitrary lines (MAL). Then, the eigen-functions of stress, strain and displacement, i.e. the angular distribution functions near a crack tip, are analyzed based on our wedge-shape non-homogeneous model. Finally, the growing direction of the interfacial crack is determined according to the relevant maximum normal stress criterion accurately. Therefore, the effective approach is provided for solving the complicated crack growing directions of an interfacial crack in non-homogeneous materials.

Abstract: The effect of different continuous material parameter functions in the non-homogeneous region on the eigen-functions of crack tip fields is studied by means of the semi-analytical numerical method based on the wedge shaped non-homogeneous sector model. The cases of the different opening angles of the non-homogeneous region, the different dissimilar material ratios, the different configurations, etc. are analyzed systematically. The result shows that the effect becomes smaller as the opening angle of the wedge shaped non-homogeneous sector becomes smaller. The valuable conclusion is drawn that the differences among the eigen-functions corresponding to the cases can be neglected as long as the opening angle is small enough for the engineering application, which facilitates the engineering application of the non-homogeneous region model.

Abstract: Crack growth behavior of S45C notched tubular specimen was studied to predict fatigue crack initiation and crack propagation under biaxial loading conditions. Stress-strain field near the hole was analyzed by ANSYS. The crack initiation lives and the crack initiation locations were predicted from strain based theories, and the analysis results were compared with the test results. Crack propagation behaviors were studied to understand the reason of crack branching and crack growth rates changing under biaxial loading conditions. Crack growth direction was also observed to find the governing factors of the fatigue damage under biaxial loading conditions.