移动边界下塑料熔体充填模拟的稳定性方法  

Stable method for melt plastics filling simulation with moving boundary

作　　者：陈路[1] 黄志高[1,2] 周何乐子 周华民 CHEN Lu;HUANG Zhigao;ZHOU Helezi;ZHOU Huamin(State Key Laboratory of Materials Processing and Die&Mould Technology,School of Materials Science and Engineering,Huazhong University of Science and Technology,Wuhan 430074,China;National Innovation Institute of Digital Design and Manufacturing,Wuhan 430075,China)

机构地区：[1]华中科技大学材料科学与工程学院,材料成形与模具技术国家重点实验室,湖北武汉430074 [2]国家数字化设计与制造创新中心,湖北武汉430075

出　　处：《华中科技大学学报（自然科学版）》2023年第6期137-143,共7页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(U20A20288);佛山市核心技术攻关项目(1920001000677)。

摘　　要：针对具有移动边界的塑料复合成形过程模拟中因网格变形而导致的数值稳定性问题,提出了塑料熔体充填模拟的稳定性方法.该方法基于任意拉格朗日欧拉法建立移动边界下充填模拟的控制方程,采用四面体单元中引入中心速度稳定的速度压力耦合计算方案,提升了移动网格下塑料熔体充填模拟的稳定性和精度;进一步针对计算过程中网格变形导致四面体单元反转错误的问题,采用引入反转单元罚函数的线弹性网格优化方法,提升了移动边界下网格变形的稳定性;数值稳定性实验表明该方法在网格极端变形和不同单元纵横比下均能稳定求解.最后采用具有柔性移动边界特征的注射压缩-热压复合成形工艺对该方法进行验证,发现移动边界下塑料熔体流动前沿的模拟误差为3.3%,实现了对此类成形工艺的精确模拟.A stable melt plastics filling simulation method was proposed for the hybrid molding processes in which there exist significant filling domain variation and numerical stability issues.The arbitrary Lagrangian-Eulerian description based governing equations was applied to describe the motion of the melt plastics under the moving boundary.A stable velocity-pressure coupling scheme by enriching the linear tetrahedral element with an extra central velocity was proposed,which can improve the numerical stability and accuracy of the filling simulation.To fix the mesh mistakes during mesh deformation,a penalty method which optimizes the mesh by penalizing the eigen values of the deformation gradient tensor was adopted.The numerical stability tests proved that the proposed method can perform stable simulation under the extreme mesh deformation and different mesh aspect ratios.Finally,an actual injection compression-forming molding experiment was carried out to validate the simulation method,and the melt plastics flow fronts were measured at different molding stages and the maximum error between simulation and experiment was 3.3%,which proved the proposed method can perform stable simulation for the melt plastics filling with moving boundary.

关 键 词：塑料成形 移动边界 网格优化 充填模拟 有限元法 

分 类 号：TH145.4[一般工业技术—材料科学与工程] TH164[机械工程—机械制造及自动化]