重力对功能陶瓷材料压制过程影响的离散元模拟

Discrete Element Method Modeling of the Influence of Gravity During Functional Ceramics Material Compaction Process

采用离散元法动态模拟了功能陶瓷材料的压制过程,分别分析了重力与微重力情况下,成型后素坯的颗粒分布、应力以及孔隙率等情况.结果显示:在重力情况下,不同粒径的颗粒分布不均匀,小粒径颗粒很大一部分集中在上冲附近,而微重力情况下,颗粒不均匀性明显减小;与此同时,与微重力情况相比,重力情况下坯体的应力分布梯度较大,靠近上冲模及下冲模处应力比中间部位应力大,而孔隙率分布梯度也较大.

Compaction process of the functional ceramic materials were dynamically simulated by discrete element method（DEM）,and the particles distribution,stress and porosity of the green compact under the actions of gravity and microgravity were also analyzed.The results showed that under the action of gravity,the distribution of different size particles was inhomogeneous,a substantial part of small size particles were found concentrated near the upper punch,while under the action of microgravity,the heterogeneity of particles was significantly reduced.Compared with microgravity condition,the distribution of stress gradients was larger under the gravity condition,and the stress near the upper and low punches was lager than that at the middle region,and the distribution gradient of the porosity was also larger.