注塑成型是聚合物加工成型的主要方式之一。而塑料制品往往具有复杂的形状，成型的物理条件对制品性能有显著影响，因此，研究复杂型腔中的注塑成型过程及相应的物理现象具有重要的理论和现实意义。本项目首先建立描述聚合物熔体流动的三维粘弹性两相流模型；其次，在笛卡尔直角网格背景下，采用Level Set函数耦合浸入边界法处理复杂边界问题，并运用Level Set方法追踪运动界面，对复杂型腔内三维注塑成型过程进行数值模拟研究；最后对注塑成型中的三维熔接痕进行追踪和动态显示，并讨论成型条件对熔接痕形成及其位置的影响。

Injection molding is one of the most widely employed methods in polymer processing. Since plastic products usually have complex shapes, and physical conditions have a significant impact on product properties, so it is of great theoretical and realistic significance to study numerically the injection molding and corresponding physical phenomena in the complex mold cavity. In this project, firstly the viscoelastic two-phase flow model will be established to describe polymer melt flows. Secondly, the coupled Immersed Boundary and Level Set method is used to deal with complicated boundary problems on the Cartesian grid, and the three dimensional injection molding process in the complex mold cavity is numerical simulated in which the Level Set method is employed to trace the moving interfaces. Lastly, the three dimensional weldlines in injection molding process are dynamically traced, and the effects of processing conditions on the weldlines and their positions are studied.