Determination of Mode I Stress Intensity Factors by Digital Speckle Correlation Method
基于数字散斑相关方法测定Ⅰ型裂纹应力强度因子

An experimental method for determining mode I stress intensity factors and crack tip position of metal specimen by digital speckle correlation method is proposed in this paper. Before test, a precrack was made in front of the notch on a Cr12MoV specimen by fatigue testing machine, the crack growth process and the displacement contour map around crack tip of specimen were measured by digital speckle correlation method under three-point bending load condition. Then the displacement data were substituted into the non-linear crack tip displacement equations, and the equations were solved by Newton-Simpson method, the crack tip position and stress intensity factor were calculated. Experimental results show that the mode I stress intensity factor, the crack tip position and crack growth length of a metal specimen can be evaluated accurately from the displacement components by the proposed method, and the stress intensity factor's evolution features during crack growth process were also revealed.