基于颗粒物质力学的铁粉末压制中摩擦特性对力链演化影响  

Influence of Tribological Characteristics on the Evolution of Force Chains in Ferrous Powder Compaction Based on Granular Matter Theory

作　　者：张炜 谈健君 张帅 陈荣昕 陈丙三 张宁 刘焜[2] ZHANG Wei;TAN Jianjun;ZHANG Shuai;CHEN Rongxin;CHEN Bingsan;ZHANG Ning;LIU Kun(School of Mechanical&Automotive Engineering,Fujian University of Technology,Fujian Fuzhou 350118,China;Institute of Tribology,Hefei University of Technology,Anhui Hefei 230009,China)

机构地区：[1]福建工程学院机械与汽车工程学院,福建福州350118 [2]合肥工业大学摩擦学研究所,安徽合肥230009

出　　处：《摩擦学学报》2022年第2期386-395,共10页Tribology

基　　金：国家自然科学基金(51975174);福建省自然科学基金(2020J01869)项目资助。

摘　　要：结合颗粒物质力学理论,通过离散元法实现铁粉末压制过程模拟并通过压制方程进行验证,针对粉末体系中的力链演化问题,提出力链特征定量分析方式,进一步通过分析不同颗粒间摩擦系数、侧壁摩擦系数与颗粒运动状态转变的方式,探讨摩擦特性对力链量化特征的影响,从而建立摩擦行为与力链演化间的联系.研究结果表明:随颗粒间摩擦系数增大,整体力链数目变少,力链方向系数、承载不均匀度及单位屈曲度均变大,而随侧壁摩擦系数增大,力链特征差异较小,则颗粒间摩擦系数较侧壁摩擦系数对力链特征演化具有更显著影响.同时发现,颗粒接触状态的改变与力链特征演化间具有对应性.研究成果将进一步拓展粉末压制中考虑摩擦行为及力链演化过程在内的粉体致密化行为理论.In order to investigate the relation between friction behavior and granular matter behavior during powder compaction,the process of ferrous powder compaction was simulated based on granular matter mechanics and the discrete element method.The reliability of simulation also was verified by compaction equation.The contact force judgment method was used to extract the force chain information of powder.The quantitative analysis parameters of force chains(the number,direction coefficient,unbalanced coefficient of bearing capacity,and buckling coefficient of force chains)were introduced to analysis the evolution of force chains on the powder system.Furthermore,the influence of tribological characteristics on the quantitative characteristics of force chains was analyzed based on the different friction coefficients between particles,friction coefficients between die wall and particles and the change of particle’motion condition.The relation between tribological characteristics and evolution of force chains was established.Results showed,the ferrous powder compaction curve obtained by compaction simulation can be fitted by Heckel compaction equation and the simulation model was reliable.With the increase of the friction coefficient between particles,the direction coefficient,unbalanced coefficient of bearing capacity,and buckling coefficient of force chains all increased but the number of force chains became fewer.And the low friction coefficient between particles can affect the force chain and was helpful for powder densification by reducing the movement obstacles between particles.The quantitative characteristics of force chains had insignificant change with the increase of the friction coefficient between die wall and particles.The evolution of quantitative characteristics of force chains at different friction coefficients between die wall and particles only had some differences during specific stage,i.e.the stage of axial strain varied from 0.1 to 0.16.Compared with the friction coefficient between die wall and part

关 键 词：颗粒物质 离散元法 粉末压制 摩擦特性 力链 

分 类 号：O369[理学—流体力学] TF121[理学—力学]