Analysis of rapid crack arrestability enhancement by structural factors in cross-joint components using a transparent elastic solid

This study investigates the effect of structural factors on rapid crack arrestability by simulating cross-joint components made of polymethyl methacrylate (PMMA). Three types of specimens were designed for double cantilever beam-type crack arrest tests; one of them was without a hole and others were with holes of different sizes. The experimental results demonstrated a significant improvement in the crack arrestability due to the larger hole at the joint part. The changes in the crack front shapes were captured successfully using a high-speed camera. The observation results indicated that the crack velocity histories were affected significantly by the change in the crack front shapes. Numerical simulations based on the extended finite element method (XFEM) were then performed on these captured crack-front-shape transitions to discuss the effectiveness of the enhancement of crack arrestability by structural factors. The numerical results revealed the same values of the stress intensity factor (K-I) at the crack-arrested locations in all the tests. K-I in the test using the specimen with the larger hole exhibited a steeper decrease at the flange. Consequently, K-I decreased by 35% in the test using the specimen with the largest hole, whose width was 46% of the upper-web thickness. This enhancement effect was equivalent to that using materials with 54% higher crack arrest toughness in terms of the stress intensity factor. Focusing on the design of structural factors could drastically enhance the rapid crack arrestability of joint components.