Theoretical Study on the Effect of Distributions of Dislocations of Subsurface Microcracks on the Growth Behavior of Deflected Main Cracks
To study the problem of a semi-infinite plane with an embedded deflected crack and a micro-crack at any position under tensile loading,the integral equation for the corresponding dislocation density is established based on the method of continuous distributions of dislocations,and its mechanical parame-ters are obtained using the Gauss-Chebyshev numerical integration method.The theoretical results are ver-ified using the finite element method.Compared with the case without microcracks,microcracks in certain directions(i.e.,the azimuth angle of the microcrack is between-90° and 45°)promote the growth of the main crack,while microcracks in other directions(i.e.,the azimuth angle of the microcrack is between 45° and 90°)inhibit its growth.The stress intensity factor at the main crack tip decreases with the increase of the embedded depth of the crack and the distance from the center of the microcrack to the tip of the deflec-ted main crack.When the azimuth angle of the microcrack is between-90° and-65°,or between-25° and 10°,the propagation direction of the main crack deflects clockwise from the original propagation direc-tion.When the azimuth angle of the microcrack is between-65° and-25°,or between 10° and 90°,the propagation direction of the main crack deflects counterclockwise from the original propagation direction.Horizontal microcracks have a greater influence on the propagation direction of the main crack and the e-quivalent stress intensity factor compared with inclined microcracks.
deflected main crackmicrocrackembedded depthpropagation directionequivalent stress intensity factor
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