粉末高速压制成形密度分布的数值模拟及影响因素分析

将研究不连续体力学行为的离散单元法应用于粉末高速压制致密化过程的研究,将粉末视为黏弹性的离散颗粒,建立粉末高速压制过程颗粒接触模型及每个颗粒的基本运动方程,推导了力与位移表达的粉末高速压制黏弹性本构关系。基于PFC软件实现了铁粉高速压制过程中粉末颗粒二维流动情况及压坯密度分布的数值模拟,模拟结果的密度分布规律与实际压制的密度分布规律较为一致;利用数值模拟结果对影响压坯密度分布的摩擦因数、高径比、双向压制因素进行了具体分析。

Numerical Simulation and Influential Factors Analysis of Density Distribution in High Velocity Compaction

Discrete element method which is used for studying mechanical behaviors of discontinuance is applied to studying the process of powder densification in high velocity compaction.Considering the powder as viscoelastic discrete particles,the contact model of particle flow and the equation of motion of each particle are established,constitutive model of viscoelastic powder in high velocity compaction described by force-displacement is deduced in detail.Based on computing software PFC for discrete element method,the process of the two-dimensional particle flow and density distribution during high velocity compaction are simulated.The density distribution of numerical simulation results coincide well with experiments in engineering application.The factors which affect the density distribution including friction coefficient,height-diameter ratio and two-directional compaction are analyzed.