Simulation Of Filling Process And Analysis Of Curing Deformation For Resin Transfer Molding

Fiber reinforced resin matrix composites have been widely used in aerospace,marine and other fields because of their excellent mechanical properties and good designability.Resin Transfer Molding(RTM)is an important manufacturing method for composite materials.Unreasonable process settings will seriously affect the flow and curing process of the resin,resulting in pores,dry spots and other defects and spring-in after demolding.In order to solve these problems,the traditional method is to adjust the process parameters and die design repeatedly by trial-and-error method,but this kind of method is low in efficiency and high in cost.Using computer simulation technology to assist research can effectively solve this problem.For RTM process,the current simulation research is mainly focused on the flow process,few on the flow-curing whole process.Therefore,it is of great practical significance to further carry out RTM process simulation and curing deformation analysis.In this paper,firstly,the mathematical models describing resin flow,heat transfer,curing kinetics and curing deformation are established to solve these problems in the simulation of RTM molding process.The parameters of the two-step reaction model describing resin curing behavior are determined by non-isothermal DSC experiment.The parameters of the CHILE(T_g)model describing resin modulus change are determined by DMA experiment,which provide important data for simulation.Secondly,the VOF multiphase flow method based on FLUENT is used to simulate the filling process of RTM.The permeability of HUL1240(0)EP glass fiber is studied by unidirectional flow experiment and radial flow experiment.The difference of permeability measured by different methods is only 3.76%.Combined with the experimental phenomenon and measurement results,the flow process of resin is simulated based on the porous media model.By introducing the influence of edge effect,the accuracy of flow front simulation is further improved.At the same time,taking L-shaped parts as an example,the filling situation under different fiber layers and gate settings is studied,which provides a reference for subsequent process experiments.Then,in order to study the change of temperature,curing degree and stress-strain in RTM curing process,the sequential coupling method is used to simulate the process based on ABAQUS.The simulation results show that the temperature field and curing degree field have the same distribution,and the change of stress is related to the process temperature in different stages.On this basis,the effects of different curing process and structural parameters on the curing deformation of L-shaped members are explored.The results are of great significance to improve product precision and optimize molding process.Finally,the vacuum assisted RTM forming experiment of L-shaped parts is carried out,and the deformation of the parts is measured by 3D scanning measuring equipment.The maximum relative error between experimental results and simulation results is 12.9%,which further proves the accuracy of the simulation method used in this paper.