粉末热等静压的离散元-有限元混合模拟

Simulation on hot isostatic pressing of power by discrete element method and finite element method

为了从微观角度仿真热等静压成形过程中粉末颗粒的变形情况,提出使用离散元和有限元混合方法建立热等静压成形的仿真模型。编写了粉末颗粒的随机填充算法,完成了包套内粉末颗粒的填充。使用上述模型,对包套内不同位置的粉末颗粒的变形情况、颗粒间孔隙消失的演化过程和成形后零件表面的形貌进行了仿真,并与已有试验结果进行了对比。仿真结果表明,包套中心的颗粒变形较小,大部分孔隙是在成形达到稳定状态之前消除的,热等静压成形零件的表面形貌主要是在达到稳定状态前形成的。离散元-有限元混合模拟可以反映热等静压成形中颗粒重排和塑性变形阶段的粉末颗粒变形。

In order to microscopically simulate powder particle deformation in hot isostatic pressing （HIP） process,a hybrid simulation model of HIP was presented by discrete element method （DEM） and finite element method （FEM）,and a random filling algorithm of power particle was written to finish the filling of powder particle in the can. Then,the power particle deformation in different locations of can,the evolution process of pore disappearing between particles and the surface morphology of parts after forming were simulated by the above model,and these simulated results were compared with the existed experiment results. The simulation results show that the powder particles in the center of can occur less deformation,and most pores disappear before the forming reaches a stable state. Furthermore,the surface morphology of formed parts by HIP is formed before the stable state. So the powder particle deformation during the particle rearrangement stage and the plastic deformation stage in HIP can be reflected by DEM-FEM hybrid simulation.