Abstract Extensive particle fracture has been noticed in projectile penetration tests. However current models for predicting projectile penetration depths do not consider particle fracture. Therefore, in order to understand the role of particle shape on single grain strength and the subsequent comminution process, single grain crushing tests on sand grains of different shapes and sizes were performed. High-resolution, three dimensional images of grain surface, were created using confocal microscope and fracture of the grains were captured with high-speed imaging. Acoustic emissions during single grain crushing was used to estimate the energy released during grain fracture. It was found that local stress fields influence particle strength and in natural granular material surface flaws maybe the critical flaw causing fracture. The estimated critical flaw size causing fracture were submicron in size. The mass specific fracture energy increased with increasing failure stress and decreasing particle size and is significantly greater than that computed from pure diametrical breaking. Except for large angular grains, mass specific energies for different shapes were similar. Angular sands required multiple events to break. The outcome of this work can be utilized in geomechanics to understand the comminution process and in power industry to estimate the energy required for comminution.

中文翻译：

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颗粒形状在决定天然二氧化硅颗粒径向压缩中的拉伸强度和能量释放中的作用

摘要 在弹丸穿透试验中发现了广泛的颗粒破裂。然而，当前用于预测射弹穿透深度的模型并未考虑颗粒破裂。因此，为了了解颗粒形状对单粒强度和后续粉碎过程的影响，对不同形状和尺寸的砂粒进行了单粒破碎试验。使用共聚焦显微镜创建晶粒表面的高分辨率、三维图像，并通过高速成像捕获晶粒的断裂。单粒破碎过程中的声发射用于估计颗粒破碎过程中释放的能量。发现局部应力场影响颗粒强度，天然颗粒材料表面缺陷可能是导致断裂的关键缺陷。估计导致断裂的临界缺陷尺寸为亚微米级。质量比断裂能随着破坏应力的增加和颗粒尺寸的减小而增加，并且显着大于根据纯径向断裂计算的结果。除了大角晶粒外，不同形状的质量比能相似。角沙需要多个事件才能打破。这项工作的结果可用于地质力学以了解粉碎过程，并在电力行业中用于估算粉碎所需的能量。不同形状的质量比能相似。角沙需要多个事件才能打破。这项工作的结果可用于地质力学以了解粉碎过程，并在电力行业中用于估算粉碎所需的能量。不同形状的质量比能相似。角沙需要多个事件才能打破。这项工作的结果可用于地质力学以了解粉碎过程，并在电力行业中用于估算粉碎所需的能量。