基于三维离散元模型粉末压制中力链对阻塞行为的影响机制  

Influence mechanism of force chain on jamming behavior in powder compaction based on 3D discrete element model

作　　者：张炜 萧伟健 袁传牛 张宁 陈荣昕 ZHANG Wei;XIAO Weijian;YUAN Chuanniu;ZHANG Ning;CHEN Rongxin(School of Mechanical and Automotive Engineering,Fujian University of Technology,Fuzhou 350118,China;Fujian Key Laboratory of Intelligent Machining Technology and Equipment,Fujian University of Technology,Fuzhou 350118,China)

机构地区：[1]福建理工大学机械与汽车工程学院,福州350118 [2]福建理工大学福建省智能加工技术及装备重点实验室,福州350118

出　　处：《粉末冶金技术》2024年第4期403-410,417,共9页Powder Metallurgy Technology

基　　金：福建省自然科学基金资助项目(2020J01869);福建省高校创新团队发展计划(闽教科[2020]12号)。

摘　　要：基于三维离散元建模技术,按照实验级配分布生成三维颗粒堆积,模拟单轴粉末压制过程,研究了压制过程中力链的演化规律及拓扑特性,通过颗粒系统中的速度与配位数分析了阻塞现象,并讨论了力链与阻塞行为间的关联机制。结果表明,在粉末压制过程中,随着上模冲压强从0逐渐增加至60 MPa,力链颗粒数目占比迅速上升至40.0%以上,高应力颗粒数目占比稳定在12.5%以上;当压强大于60 MPa后,力链开始出现弯曲并形成环状结构,从而导致了阻塞现象的产生,因此将60 MPa定为阻塞点。阻塞现象对粉体的致密化产生了影响,在压制过程中,与下层粉体颗粒相比,上层区域的粉体颗粒轴向速度更快,变化幅度更大;当压制结束时,上层区域的粉体颗粒致密化程度比下层区域更高。To simulate the uniaxial powder compacting process,the 3D particle accumulation was generated by 3D discrete element method technology based on the experimental grading ratio.The evolution law and topological properties of the force chains were investigated during the powder compacting process,the jamming phenomenon was further studied using the velocity and coordination number of particles,and the correlation mechanism between the force chain and jamming behavior was discussed.The results show that,as the compression strength of the upper die gradually increases from 0 to 60 MPa,the number proportion of force chain particles rapidly increases to more than 40.0%,while the number proportion of high stress particles is stable above 12.5%.When the pressure exceeds 60 MPa,the force chains bend and form ring structure,causing the jamming phenomenon.As a result,the jammed point is set to 60 MPa.The jamming phenomenon also effects the powder densification.The axial velocity of the powder particles in the upper area is faster and the rangeability is larger than that of the powder particles in the lower area during the powder compaction process.However,when the compaction process is completed,the densification of the powder particles in the upper area is higher than that of the powder particles in the lower area.

关 键 词：粉末压制 颗粒物质 离散元 阻塞 力链 

分 类 号：TF122.1[冶金工程—粉末冶金]