圆盘内裂纹扩展断裂试验及数值模拟研究

鉴于含裂纹的巴西圆盘试验多集中于二维或表面裂纹,而对含纯封闭内裂纹的巴西圆盘断裂研究较少的问题,开展了含90°三维内裂纹的树脂巴西圆盘试样单轴压缩试验,分析了裂纹扩展过程特征,并基于M积分及最大拉应力准则研究了KⅠ、KⅡ、KⅢ分布规律,通过断裂力学有限元软件FRANC3D实现内裂纹扩展全过程模拟。结果表明,含90°内裂纹试样在单轴压缩下裂纹破坏形态为竖直张拉裂纹;达到峰值荷载29.13kN时试样瞬间被劈裂为两半,内裂纹扩展速度达到700mm/s,对试样扩展、破坏形态及断口特征产生显著影响;通过数值模拟得出内裂纹尖端扩展路径,短轴端扩展速率最大,且数值模拟结果与试验相符。

Test and Numerical Simulation of Propagation and Fracture of Brazilian Disc with Embedded Crack

In view of the fact that the Brazilian disc tests with cracks are mostly concentrated on two-dimensional or surface cracks, and the less research on Brazilian disc specimen with pure closed internal crack, the uniaxial compression test of Brazilian disc specimen with 90° three-dimensional internal crack was carried out. The characteristics of crack propagation process was analyzed. Based on M integral and maximum tensile stress criterion, the distribution law of KI, KII and KIII was studied. The whole process of internal crack propagation was simulated by FRANC3D. The results show that the crack failure morphology of the crack specimen with 90° under uniaxial compression is vertical tensile crack; When the peak load is 29.13 kN, the specimen is instantaneously split into two halves, and the internal crack propagation speed reaches 700 mm/s, which has a significant impact on the sample expansion, failure mode and fracture characteristics; The internal crack tip extension path is obtained by numerical simulation, and the short axis end expansion rate is the largest; Furthermore, the numerical simulation results are consistent with the test.