ABSTRACT

A discrete element model has been developed to simulate the packing process of fibre/polymer composite powder for powder bed fusion additive manufacturing. The geometric shapes of polymer powder particles and fibres are represented by multi-sphere particles and individual cylinders with round ends, respectively. The numerical model can help to understand the flow dynamics of composite powder particles and the formation mechanisms of voids in powder packing processes. The numerical model has been utilised to analyse the effects of packing parameters on the packing quality of the powder bed. The simulation results suggest that the increase of the powder layer thickness is beneficial for increasing the packing density and lowering the surface roughness of the powder bed. A high roller spreading velocity degrades the packing quality of the powder bed. A small number of fibres in the composite powder particles are in favour of the packing quality, while excessive fibres reduce the packing quality of the powder bed.

摘要

已经开发了离散元模型来模拟用于粉末床熔融增材制造的纤维/聚合物复合粉末的包装过程。聚合物粉末颗粒和纤维的几何形状分别由多球颗粒和带有圆形末端的单个圆柱体表示。该数值模型有助于理解复合粉末颗粒的流动动力学和粉末填充过程中空隙的形成机制。利用数值模型分析了填料参数对粉床填料质量的影响。模拟结果表明，粉层厚度的增加有利于增加堆积密度和降低粉床的表面粗糙度。高辊铺展速度会降低粉末床的填充质量。