Abstract To investigate the crack propagation and failure mechanisms of brittle materials in the Brazilian tests, an acoustic emission (AE) simulation was implemented in the Discrete Element Method. AE location and magnitude were monitored during the whole process of the simulation to detailedly observe crack initiation and associated AE evolution. Moment tensors were directly calculated by the forces and motions of the particles and decomposed into isotropic and deviatoric parts. According to the decomposition results of moment tensors, AE events (microcracks) can be classified into explosive (tensile), shear and implosive sources. Explosive sources were found to dominate both the total number and energy emission, followed by shear sources and finally implosive sources. AE distributions of different AE types were compared with the stress distribution to explore the relation between failure evolution and intrinsic stress state of the Brazilian test. Furthermore, the approach was applied to the compression test with a single flaw. Comparisons with experimental results indicated that the AE simulation can overcome the shortcoming of signal missing near the peak load in experiments and is approved to be an effective and accurate way to study rock fracture mechanism.

中文翻译：

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使用矩张量反演模拟巴西测试中的声发射

摘要 为了研究脆性材料在巴西试验中的裂纹扩展和破坏机制，采用离散元方法进行声发射 (AE) 模拟。在整个模拟过程中监测 AE 位置和幅度，以详细观察裂纹萌生和相关的 AE 演变。矩张量由粒子的力和运动直接计算，并分解为各向同性和偏心部分。根据矩张量的分解结果，AE事件（微裂纹）可分为爆炸（拉伸）源、剪切源和内爆源。发现爆炸源在总量和能量排放中占主导地位，其次是剪切源，最后是内爆源。将不同 AE 类型的 AE 分布与应力分布进行比较，以探讨巴西试验的失效演变与内在应力状态之间的关系。此外，该方法还应用于具有单个缺陷的压缩测试。与实验结果的比较表明，声发射模拟可以克服实验中峰值载荷附近信号丢失的缺点，被认为是研究岩石破裂机制的一种有效而准确的方法。