The Application Of Multiscale Finite Element Method In Liquid Composite Molding Simulations

This issue is the source of the National Natural Science Foundation of "molding resin membrane infiltration and the quality control of non-isothermal simulation coupled Theoretical and Experimental Research."(No.50573060)Liquid composite molding(LCM) process is a high-powered and cost-effective fabrication technique appearing recently.In LCM process,resin flow through dry fibers is often seen as the movement of porous media flow.Porous media composites are usually solved by numerical methods due to complicacy of geometric structure and distribution.For attaining basic engineering precision,the subdivision of the mesh must be very fine.It will cause huge calculated amount, and sometimes even hard to implement.Multiscale finite element method is one of the most important multiscale numerical calculation methods in recent years.It can efficiently capture the large scale behavior of the solution without resolving all the small scale features by constructing the multiscale finite element base functions adaptive to the local property of the differential operator.It can overcome the shortcomings of traditional methods.The main research works and production of this paper as follow:1) The fundamental principles and solving method of multiscale finite element method are first introduced,including the construction of multiscale basic functions,the boundary conditions of basic functions and the oversampling method.Then,we analyzed error estimates of multiscale finite element method by homogenization theory in two cases.The results have shown that multiscale finite element method is better than the standard finite method,especially when h＞ε.2) This paper focus on the construction of resin flow model in LCM process, numerical calculation method of model which combined multiscale finite element method with control volume finite element method,and moreover,computer simulation program of resin flow process.3) We simulated the resin flow by control volume finite element method and multiscale control volume finite element method respectively,and compared the results with two methods.Under different process parameters of the molding process simulation,the analysis in this paper forecasted the track of the resin flow, the location of flow front and the filling time.We simulated the resin flow with different pressure and studied the influence on molding pressure and flow front with different inlet and outlet gates.According to the results,the proposed numerical calculation method is feasible.It not only established theoretical basis for LCM process but also proposed a new method for molding parameter optimization,mold design and product quality control.