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冲击载荷作用下准脆性材料的动态断裂一直是关注的热点问题,Ⅱ型裂纹试样受冲击剪切时其裂纹扩展方向同材料力学性质和冲击速度等密切相关。应用岩石动态破裂过程动态分析系统软件,对单边平行双裂缝试样开展了冲击载荷作用下的裂纹动态扩展数值模拟,分别研究了不同材料力学性质、材料均质度、入射应力脉冲幅值和历时对II型裂纹动态扩展的影响。数值模拟结果表明,纯II型裂纹在动荷载作用下的扩展,不仅受到剪切损伤,而且还存在拉伸损伤;准脆性材料的非均匀性导致了主裂缝周围产生大量微裂纹的破坏,影响裂缝的分岔和内部的应力值;应力幅值和应力脉冲历时分别超过某一定值时,主裂缝将出现分叉现象,试样的破坏程度加剧,其研究结果对于深入揭示准脆性材料在动荷载作用下II型裂纹扩展的规律及准脆性材料的损伤断裂机制具有重要的参考价值。
The dynamic fracture of quasi-brittle materials under impact load has always been a hot issue. The crack propagation direction of type Ⅱ crack specimen is closely related to the mechanical properties and impact velocity of the material under impact shear. The dynamic crack propagation analysis software was used to simulate the dynamic crack propagation under uniaxial and parallel double crack specimens under impact loading. The mechanical properties, material homogeneity, incident pulse amplitude and Effect of Duration on Type II Crack Dynamic Expansion. The numerical simulation results show that the pure Type II crack propagates under dynamic loading not only by shear damage but also by tensile damage. The non-uniform quasi-fragile material leads to the destruction of a large number of micro-cracks around the main crack, Crack bifurcation and internal stress value; stress amplitude and stress pulse duration over a certain value, respectively, the main crack bifurcation phenomenon, the specimen damage worsened, the results of the study for the in-depth disclosure of quasi- The law of type II crack propagation under load and the damage and fracture mechanism of quasi-brittle materials have important reference value.