A field-enriched finite element method for brittle fracture in rocks subjected to mixed mode loading

摘要

In this paper, a field-enriched finite element method is proposed to simulate the crack propagation and coalescence of brittle rocks subjected to mixed mode loading. The basic theory is derived, and numerical implementation is achieved. The mixed fracture characteristics and fracture parameters of brittle rocks are studied, and the disctype specimens are taken as sample configurations. Firstly, a centrally cracked circular disc (CCCD) is used to verify the correctness and accuracy of the numerical model in dealing with mixed fracture problems. The field distribution and crack propagation path are also analyzed. The final failure mode is compared with the experimental observation and previous numerical result. Then, three semi-circular bending (SCB) configurations are employed to investigate the effect of different factors on the fracture patterns under mixed mode loading. The numerical results are qualitatively displayed, and the influence of each controlling factor on the crack initiation angle is also quantitatively analyzed. Finally, Brazilian disk specimens with two and three parallel flaws are used to simulate the fracture process. The present numerical results are in good agreement with those obtained by the other numerical methods, which indicates that the proposed numerical method has ability to simulate cracks propagation and coalescence.