【作者】 郭建娟；

【导师】 晏石林；

【作者基本信息】 武汉理工大学 ， 固体力学， 2002， 硕士

【摘要】 片状模塑料(简称SMC)模压成型工艺是近年来在国内外受到普遍重视的短纤维增强复合材料成型工艺。在模塑料从熔融状态到固体状态的过程中，纤维／基体混合物在模具中发生流动变形，变形改变了纤维的取向。在流动结束后，纤维的最终取向也将保留在固体部件中，纤维的取向状态对部件的力学和物理性能都有很大的影响。因而研究短纤维增强聚合物的流变性能，流动过程中的纤维取向就显得极为重要。同时，准确的模拟对目前的加工过程中的错误诊断以及流程控制都有重要意义。本文在国家自然科学基金项目的资助下，研究了SMC的模压流动及其充模过程中的纤维取向行为。 在文章的理论部分，首先分析了SMC熔体的流变行为，基于流体力学基本理论，引用广义Hele-Shaw模型作为SMC模压流动的理论模型。接着研究了在流动的悬浮液中描述和预测纤维取向的理论，导出了二维流场中纤维取向的数学模型。在数值计算与分析中，根据SMC模压流动分析和纤维定向分析的数学模型，编制SMC模压流动及充模过程中纤维取向的计算机程序。程序中用有限单元控制体方法模拟模压流动，用表征纤维取向的张量和有限元伽辽金方法来解决瞬时纤维取向方程，用计算机图形原理编程实现对SMC流动轨迹、纤维取向分布的计算机模拟。最后通过实例对二维薄板在恒定合模速率下的纤维取向进行了计算机模拟计算，其结果对SMC铺料的方式、模具设计以及压制工艺参数的最终确定具有一定的理论指导意义。更多还原

【Abstract】 As an important process of fibre-reinforced composites, sheet molding compound (SMC) technology draws worldwide attention recently. The orientation of the reinforcing fibres changes during the deformation process, and when the matrix solidifies the final orientation pattern is retained in the part. This orientation plays a key role in determining the mechanical and physical properties of the finished product. Therefore, it is very important to have some insight into the change of fibre orientation during flow.At first the rheology behavior of SMC is analyzed and a Generalized Hele-Shaw model (GHS), based on the theory of fluid mechanics, is adopted as theory model of compression molding. Then theories of describing and predicting fibre orientation in flowing suspensions are investigated and a mathematics model of planar orientation in a two-dimensional domain is derived. In the numerical methods section, a finite element/control volume mold filling simulation, a tensor representation of fibre orientation and a finite element solution of the transient fibre orientation equations are combined in the program. The input data and output results are visualized by means of finite element software. Finally the orientation states of 2-D thin plate are simulated in a certain velocity. The numerical results will be of a certain theoretical function to placement of SMC charge, design of mold and optimization of the technological parameters.更多还原