含双空孔缺陷试件三点弯曲冲击试验.

In order to study the action mechanism of double-hole defects on moving cracks, a digital laser dynamic caustics system was used to test the impact fracture of a three-point flexural beam of a plexiglass plate with double-hole defects. The crack propagation path, tip dynamic strength factor, propagation velocity and the change law of caustic speckle under double-hole defects were analyzed and studied. The results show that the cracks moving around are attracted by the empty hole defects, and the trajectory of the cracks is changed. The crack initiation difficulty of specimens with double-cavity defects increases significantly, and the critical stress intensity factor of crack initiation increases by 24. 29%. When the moving crack is close to the double-empty hole defect, the double-empty hole defect has an obvious inhibition effect on the crack growth, and when the crack passes through the double-empty hole defect center, the double-empty hole defect has a promotion effect on the crack growth. [ABSTRACT FROM AUTHOR]