可破碎颗粒体在动力载荷下的耗能特性
ENERGY DISSIPATION CHARACTERISTICS OF CRUSHABLE GRANULES UNDER DYNAMIC EXCITATIONS
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摘要: 采用离散元的数值方法, 通过连接键将若干小颗粒绑定为一个具有不规则外形的大颗粒体, 设置不同连接键强度模拟了颗粒体在外加动力载荷下破碎过程, 并探讨其中系统能量耗散特性. 计算结果表明, 颗粒体的破碎程度决定了系统能量耗散率, 即内部耗能占外界输入能量的比例. 破碎率越高, 颗粒间相互摩擦和碰撞越剧烈,系统能量耗散率越高. 同时, 在循环载荷下系统内颗粒体破碎绝大部分发生在加载初期, 随着颗粒体的分解破碎速率逐渐减小, 系统耗能能力也随之降低.Abstract: Using the discrete element method (DEM) with cluster, different degrees of particle crushing by setting various contact bond thresholds under external dynamic excitation are implemented, and their energy dissipation characteristics are also discussed. Numerical results indicate that the particle breakage ratio has a great influence on the energy dissipation ratio which is defined as consumed energy to the input energy. As the particle breakage ratio rises, which intensify the friction and the collision between particles, the energy dissipation ratio increases. Besides, most cluster disintegration happens on the early stage of cyclic loading. Gradually, the breakage rate slows down, and the energy dissipation ratio reduces.