Dynamic crushing characteristics of coals are closely related with energy absorption and release of coals under certain strain rate. Hence, it is necessary to investigate energy dissipation laws of coal crushing under the impact loads with different strain rates. Based on the dynamic and static mechanical tests, crushing energy, total absorption energy, total releasable elastic latent energy, and relations between fractal feature of fragments, mean particle diameter and energy during crushing behaviors of outburst coal and nonoutburst coal were investigated. According to research results, crushing energy, total absorption energy, and releasable elastic latent energy of outburst coal and nonoutburst coal are related with strain rate, and they present exponential growths with the increase of the strain rate. However, the energy dissipation rate (ratio of crushing energy and incident energy) was basically constant at about 10%∼20%, that is, energy dissipation rate is a variable unrelated with strain rate. There is a good logarithmic relationship between the dynamic compressive strength of coals and the absorption energy density and elastic latent energy density, and dynamic comprehensive strength of coals has important impacts on energy absorption. The fractal features of coal fragments were obvious under dynamic impacts. The higher fractal dimension of fragment and the smaller mean particle diameter of experimental fragments bring the greater energy needed.

中文翻译：

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冲击载荷下碎煤耗能规律研究

煤的动态破碎特性与煤在一定应变率下的能量吸收和释放密切相关。因此，有必要研究不同应变率冲击载荷下煤破碎的能量耗散规律。通过动、静态力学试验，研究了突出煤和非突出煤破碎行为的破碎能、总吸收能、总释放弹性潜能，以及碎片分形特征、平均粒径与能量之间的关系。研究结果表明，突出煤和非突出煤的破碎能、总吸收能和可释放弹性潜能与应变率有关，并且随着应变率的增加呈指数增长。然而，能量耗散率（破碎能与入射能之比）基本恒定在10%～20%左右，即能量耗散率是一个与应变率无关的变量。煤的动态抗压强度与吸收能量密度和弹性潜能密度之间存在良好的对数关系，煤的动态综合强度对能量吸收有重要影响。动力冲击作用下煤碎片的分形特征明显。碎片的分形维数越高，实验碎片的平均粒径越小，所需的能量越大。煤的动态抗压强度与吸收能量密度和弹性潜能密度之间存在良好的对数关系，煤的动态综合强度对能量吸收有重要影响。动力冲击作用下煤碎片的分形特征明显。碎片的分形维数越高，实验碎片的平均粒径越小，所需的能量越大。煤的动态抗压强度与吸收能量密度和弹性潜能密度之间存在良好的对数关系，煤的动态综合强度对能量吸收有重要影响。动力冲击作用下煤碎片的分形特征明显。碎片的分形维数越高，实验碎片的平均粒径越小，所需的能量越大。