锤式破碎机冲击速率直接影响着岩石破碎效果，为研究锤头冲击速率对青砂岩破碎效果及断裂能利用效率的影响，结合物理试验与细观参数标定，建立了青砂岩宏观−细观力学响应关系，采用颗粒流程序分析了锤式破碎机不同冲击速率下青砂岩的应力链特点、损伤劣化特征、声发射及裂纹变化，并研究了断裂能利用效率。结果表明：①青砂岩在破碎过程中，破坏微单元内部以拉力链为主，破坏边缘以压力链为主，在未破坏微单元内部压力链与拉力链相互交叉成网状，拉力链引起裂纹扩展，最终破坏是压力链和拉力链共同作用的结果。②青砂岩破坏形态分为局部破坏、扩展破坏及加剧破坏阶段，破坏微单元数量分为快速增加、逐渐变缓及稳定阶段。冲击速率越大，破坏微单元数量稳定值增加幅度越大，且破坏微单元数量与冲击速率近似服从直线分布。③随着冲击速率的增加，青砂岩裂纹累计数量分为快速增加与稳定阶段。裂纹萌生阶段，以剪切裂纹为主，初始输入能量主要用于剪切裂纹的生成，而后拉伸裂纹所占的比例逐渐增加，且最终以拉伸裂纹为主。④青砂岩在破坏过程中，断裂能分为快速增加、逐渐变缓及稳定阶段。断裂能利用效率分为快速增加、缓慢增加及缓慢下降阶段，最大值为10.851%，并建立了断裂能利用效率与冲击速率的定量化关系。研究结果不仅从细观角度对青砂岩破碎效果及断裂能利用效率进行了初步探索，也可为锤式破碎机破碎过程中工艺参数的合理选择提供参考。

The impact velocities of hammer crusher directly affect the crushing effect of rock. In order to study influence of impact velocities of hammer head on the crushing effect and utilization efficiency of fracture energy in green sandstone, macroscopic and microscopic mechanical response relationship of green sandstone was established by combining with physical experiments and microscopic parameter calibration. The characteristics of stress chain, characteristics of damage and degradation, acoustic emission and changes of crack in green sandstone under different impact velocities of hammer crusher were analyzed using particle flow code, and the utilization efficiency of fracture energy was studied. The results show that: ① During the crushing process of green sandstone, the internal part of destructive micro-unit is mainly composed of tension chain, and the edge of failure is mainly composed of pressure chain. In the undamaged micro-unit, the pressure chain and tension chain cross each other to form network. The tension chain cause extension of crack, and the final failure is the result of the combined action of pressure chain and tension chain. ② The failure pattern of green sandstone is divided into the stage of local failure, extended failure, and intensified failure. The number of destructive micro-unit is divided into the stage of rapid increase, gradual slowing, and stabilization. The larger the impact velocities, the greater the stable increase in the number of destructive micro-unit, and the number of destructive micro-unit approximately follows linear distribution with the impact velocities. ③ With the increase of impact velocities, the cumulative number of crack in green sandstone is divided into the stage of rapid increase and stabilization. In the stage of crack initiation, shear crack are the main type, and the initial input energy is mainly used for the generation of shear crack, while the proportion of tensile crack gradually increases, and eventually tensile crack are the main type. ④ During the failure process of green sandstone, the fracture energy can be divided into the stage of rapid increase, gradual slowing, and stabilization. The utilization efficiency of fracture energy can be divided into the stage of rapid increase, slow increase, and slow decrease, with the maximum value of 10.851%, and the quantitative relationship between utilization efficiency of fracture energy and impact velocities is established. The result of the study not only provide preliminary exploration of the crushing effect and utilization efficiency of fracture energy in green sandstone from microscopic perspective, but also provide reference for the reasonable selection of process parameters in the crushing process of hammer crusher.