Study On The Effect Of Injection Molding Process On Mechanical Properties Based On Glass Fiber Reinforced PMH Technology

In recent years,with the global energy and environmental problems becoming more and more intensive in the automotive industry,the call for energy conservation and emission reduction is mounting.Glass fiber reinforced plastic-metal hybrid(PMH)technology,an emerging means of lightweight which integrates metal and composite materials' advantages,characterizes with light quality and high strength,as well as easy-to-shape.Moreover,it has easy access to design and has the characteristic to implement parts modular production,therefore,its function and cost can reach a good balance.Now it draws more and more attention.This paper intends to investigate the effects of process parameters on the mechanical properties of glass fiber reinforced PMH via experimental design and finite element simulation.Firstly,it gives a brief overview of the overseas and domestic research status and background of PMH technology,and summarizes the existing shortcomings of PMH technology in application and research.On this basis,the research ideas and methods of this paper are put forward.First of all,according to the requirements of fiber reinforced PMH structure's process and performance,this paper introduces and analyses the principle of injection molding and its key control parameters.Besides,this paper also discusses the effects of PMH component material selection,metal pretreatment and injection molding parameters on the quality and mechanical properties of PMH components.Then,a new method based on material parameter mapping is proposed to solve the existing difficulties and limitations of numerical analysis of fiber reinforced PMH structure in injection molding.Using the Multicontinuum(MTC)theory,the composite average amount in the microscopic representative volume element(RVE)is decomposed into its internal components(fibers and resins),and the damage evolution and failure of the composite material is predicted by the relationship between the average amount of components so as to avoid the establishment of complex and completely simulated actual micro-mechanical stress field model.Based on this material model,The result information of the flow analysis is mapped into the structural analysis model.This method can realize a large number of analytical data from the grid model suitable for the analysis of the flow analysis to the grid model suitable for structural analysis,and apply the result information such as warping shrinkage deformation and residual stress during the injection process to the subsequent structural analysis,which improves the efficiency of calculation and the accuracy of the results.Based on this method,the structure of a typical vehicle beam is modeled.The effects of the bond strength of the fiber reinforced plastic-metal interface on the residual stress,the warping shrinkage deformation and the mechanical properties of the vehicle are studied.The results show that when the interface bonding strength exceeds 20MPa,the warping shrinkage deformation of plastic parts can be ignored,the PMH structure in the typical operating conditions of the vehicle can maintain a stable level of mechanical properties.Finally,the parameters of the injection molding process were optimized by using the Taguchi experimental design method and the results show that there are several process parameters which exert great impact on PMH components' quality and mechanical properties.They are packing pressure,melt temperature,packing time,metal insert temperature and mold temperature.The multivariate regression mathematical model of process parameters and residual stress at the polymer-metal interface was established by using the stepwise regression function of MATALB.The multivariate regression mathematical model was further solved by simulated annealing method,and the optimal combination of process parameters was obtained.