Mao Haiying, Hu Cong, Xue Jianfeng, Li Taicheng, Chang Haotian, Fu Zhaoqing, Sun Wenhui, Lu Jieyu, Wang Jing, Yu Shuyang
School of Civil and Architectural Engineering, Guangxi University of Science and Technology, Liuzhou 545006, China.
China Renewable Energy Engineering Institute, Beijing 100120, China.
Materials (Basel). 2024 Jul 18;17(14):3547. doi: 10.3390/ma17143547.
Cracks in rock and concrete have a great adverse effect on the stability of engineering structures; however, there are few studies on X-shaped fissures which widely exist in rock and concrete structures. Based on this background, three-point bending fracture tests of SCB specimens containing X-shaped fissures are carried out. The momentum equations in the SPH method are improved, and the crack propagations of SCB specimens under three-point bending are simulated. The results show that cracks grow simply along the vertical direction in the sample with no X-shaped fissures, and the existence of an X-shaped fissure changes the crack growth path and final failure modes of the SCB samples. The crack propagation simulation results are consistent with the experimental results, which verifies the rationality of the improved SPH method. The load-displacement curves mainly present three typical stages: the initial compaction stage, linear elastic deformation stage, and failure stage. The peak load decreases first then increases with an increase in eccentricity. With an increase in X-shaped fissure length and decrease in X-shaped fissure angle, the peak load decreases. The damage counts remain at 0 at the initial loading stage, corresponding to the initial compaction stage and the linear elastic deformation stage, and increase sharply at the later loading stage, corresponding to the failure stage, which is consistent with the experimental results. The influence mechanisms of X-shaped fissures on the crack propagation paths are discussed; the existence of different X-shaped fissure morphologies aggravate the tensile stress concentration at specific positions, leading to different crack propagation modes in the experiments. The research results can provide a certain reference for understanding the failure mechanisms of engineering structures containing X-shaped fissures and promote the applications of the SPH method into the simulations of cross-fissure crack propagations.
岩石和混凝土中的裂缝对工程结构的稳定性有很大的不利影响；然而，对于广泛存在于岩石和混凝土结构中的X形裂缝，相关研究较少。基于此背景，开展了含X形裂缝的SCB试件的三点弯曲断裂试验。对光滑粒子流体动力学（SPH）方法中的动量方程进行了改进，并模拟了SCB试件在三点弯曲下的裂纹扩展情况。结果表明，在无X形裂缝的试件中，裂纹仅沿垂直方向扩展，而X形裂缝的存在改变了SCB试件的裂纹扩展路径和最终破坏模式。裂纹扩展模拟结果与试验结果一致，验证了改进后的SPH方法的合理性。荷载-位移曲线主要呈现三个典型阶段：初始压实阶段、线弹性变形阶段和破坏阶段。峰值荷载随偏心距的增加先减小后增大。随着X形裂缝长度的增加和X形裂缝角度的减小，峰值荷载减小。损伤计数在初始加载阶段保持为0，对应于初始压实阶段和线弹性变形阶段，而在后期加载阶段急剧增加，对应于破坏阶段，这与试验结果一致。讨论了X形裂缝对裂纹扩展路径的影响机制；不同X形裂缝形态的存在加剧了特定位置的拉应力集中，导致试验中出现不同的裂纹扩展模式。研究结果可为理解含X形裂缝的工程结构的破坏机制提供一定参考，并推动SPH方法在交叉裂缝裂纹扩展模拟中的应用。
