片状模塑料压成型理论与数值模拟研究

Sheet Molding Compound(SMC) is a new type of charge which is used for compression molded technology of fibre reinforced composites. It is specially used to produce sheet-like composites products. Because of the many excellent characteristics such as light-weight and high-strength, anticorrosion and heat insulation, brightness of surface, stable quality, low cost and high productive efficiency, the SMC compression molded products have been widely applied to the fields of automobile, construction, chemical engineering, space navigation and so on. In the compression molding of SMC, the initial charge is generally not full of the whole mold, and partial charge will arrive at the mold boundary by flowing under the action of pressure and temperature. Therefore the rheology properties and its variational rules of SMC in the compression molding are the bases to select reasonable technological parameters such as temperature, pressure, mold closing velocity and mold filling time. It is the key technique for the optimization of compression molding technology to find out the quantitative relationships among these parameters. In addition, the flowing characteristics of SMC in the mold will directly affect the fibre orientation and distribution in cured products. It is very important for the quality of products that how to ensure the fibre flows together with the resin, and how to predicate and control the fibre orientation in mold filling process. Relative to thermosetting SMC, the thermoplastic SMC and its products have the advantages of lighter-weight, better anticorrosive property, shorter molding period, lower cost and moldable repeatedly. Therefore it has got rapidly development in recent years. Because the permeability between fibres and thermoplastic matrix is generally not good, how to improve the interfacial adhesion property becomes one of the most important factors for the high quality thermoplastic SMC products.. In this researching project, the rheology properties of SMC are studied by theoretical and experimental methods. The mathematical model for SMC compression molding analysis is established. Using the finite element methods and computer simulation techniques, the numerical calculation and flowing simulation programs are completed by mesh expanding method and control volume method respectively. The compression molded flowing and mold filling process of SMC are realized. The velocity field, displacement field, pression field and short fibre orientational state distribution of the charge at any stages of compression molding are obtained. The relations of viscosity, pressure, mold closing velocity and mold filling time are analyzed. For thermoplastic SMC(GMT-PP, for example), the effects of fibre surface treatment and glassfibre/PP interfacial adhesion quality on mechanical properties of composites are studied.

本项目拟在对片状模塑料（SMC）流变特性研究的基础上，建立SMC模压成型理论分析模型，实现SMC模压流动和充模过程的计算机数值模拟以及对模压制品纤维取向和性能质量进行预猓MC流变性质与模压成型工艺条件之间的定量关系。因此，本项目将为复合材料干法成型技术奠定理论基础，为优化成型工艺参数和模具设计提供依据。