Stress Intensity Factors of Double and Multiple Edge Cracks

In this paper the interaction of multiple edge cracks in a semi-infinite plate is considered. The problem is formulated as a system of hypersingular integral equations using the stress field due to a force doublet as a fundamental solution. In the numerical calculations, unknown functions are approximated by fundamental density functions and Chebyshev polynomials. First, two edge cracks A and B having different crack lengths and inclination angles are analyzed and the effect of crack B upon crack A is investigated. The stress intensity factor (SIF) of crack A is found to be almost constant independent of inclination angle B if the tip of crack B is fixed. Second, periodic edge cracks are systematically analyzed varying the number, distance and angle of cracks. The interaction effect is found to occur mostly due to the distance independent of the angle. Analytical results are also shown when crack parameters are changed slightly from average values in almost equally spaced multiple edge cracks