作　　者： ; ; ; ; ;

机构地区： 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

出　　处： 《高分子学报》 2011年第2期173-179,共7页

摘　　要： 采用GLS(Galerkin/least-squares)、SUPG(Streamline upwind/Petrov-Galerkin)、GGLS(Galerkin gradientleast-squares)等方法对塑料注射成型过程进行三维数值模拟以获取速度、压力与温度场,基于剪切应力引起分子链取向并导致平衡熔点升高的假设推导了非等温剪切诱导结晶动力学模型,引入了注射成型过程与结晶相互作用的计算模型,建立了三维流场中结晶过程的稳定有限元计算模型.不同成型工艺条件下的数值算例表明,充模过程中一般注射时间较短,熔体温度较高,塑料结晶量很小,可以忽略不计;工艺条件决定最终制品的结晶分布,可以通过改变工艺条件获得所需要的结晶形态分布,结晶过程释放的潜热对充模后冷却过程中的温度场具有重要影响. The crystallinity distribution of polymers has a significant dependence on injection processing and determines the part properties.Speed,pressure and temperature fields are obtained from 3D numerical simulation by employing GLS（Galerkin/least-squares）,SUPG（Streamline upwind/Petrov-Galerkin） and GGLS（Galerkin gradient least-squares） methods.The non-isothermal shear stress-induced crystallization kinetics models are proposed based on the hypothesis that shear stress induced orientation of polymer chains increases the equilibrium melting temperature.The relationship between crystallinity and injection processing is modeled.SUPG method is used for the stabilized finite element formulation of crystallinity evolution in flow.Simulations for polypropylene were carried out under different processing conditions such as different injection speeds and mold temperatures,melt temperatures,and the results show that crystallinity is very low and can be neglected when the filling stage is over because of short injection time and high melt temperature.Crystallinity distribution in the final part is determined by processing parameters which can be varied to bring on the special crystallinity distribution.Latent heat due to crystallization may often affect the temperature field very much during the cooling stage.

关 键 词： 注射成型 剪切诱导 结晶动力学 结晶分布 潜热

领　　域： [化学工程]