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Analysis of 3D brittle particle impact crushing characteristics based on CDEM

DOI：10.7511/jslxCMGM202205

 作者 单位 E-mail 刘新明 中国科学院 力学研究所, 北京 100190中国科学院大学 工程科学学院, 北京 100049 冯春 中国科学院 力学研究所, 北京 100190中国科学院大学 工程科学学院, 北京 100049 fengchun@imech.ac.cn 林钦栋 西安近代化学研究所, 西安 710065

通过在连续-非连续单元法(CDEM)中引入考虑应变率效应的断裂能本构以及能量统计算法,实现了球体冲击破碎过程中损伤破裂程度及能量演化的定量分析。计算结果表明,冲击破碎过程分为接触蓄能阶段、损伤破碎阶段和碎块飞散阶段。首先,颗粒的部分动能转化为单元弹性变形能,随后这部分变形能和动能迅速转化为摩擦消耗、阻尼消耗及弹簧断裂能,破碎基本完全后碎块继续飞散。不同冲击速度下,颗粒分别出现了反弹、开裂、破碎和粉碎的现象。随冲击速度的增加,D50的变化速率逐渐放缓,破碎块度逐渐趋于稳定;破裂度、损伤度以及平均损伤因子的变化速率先增加后放缓,颗粒破坏以拉伸破坏为主。以上结论可为脆性材料冲击破碎工艺的优化设计提供依据。

By introducing the fracture energy mechanism considering the strain rate effect and the statistical energy algorithm into the continuum-discontinuum element method (CDEM),the quantitative analysis of the damage and fracture degree and energy evolution in the process of spherical impact crushing is realized.The results show that the impact crushing process is divided into contact energy storage stage,damage fracture stage and fragmentation stage.First of all,part of the kinetic energy of the particles is transformed into the elastic deformation energy of the element,and then this part of the deformation energy and kinetic energy is rapidly transformed into friction-induced energy dissipation consumption,damping dissipation and spring fracture energy.After the crushing is nearly complete,the fragments continue to disperse.At different impact velocities,the particles rebound,crack,break and smash.With the increase of impact velocity,the change ratio of D50 gradually slows down and the fragmentation gradually becomes stable.Secondly,the change ratio of fracture degree,damage degree and average damage factor increase and then slow down.The particle damage is mainly through tensile failure.The above conclusions can provide a basis for the optimization design of impact crushing process of brittle materials.