Analysis Of Resin Filling For Stitched Foam Core Sandwich Structure Composites By VARTM Process

Stitched foam core sandwich structure composite is a kind of high-performance composite which is consisted of upper and lower fiber panels and the middle foam core. Stitched foam core sandwich structure preforms are impregnated with a resin by the liquid molding process. The use of suture technique can prevent the fiber panel and the layer of the foam core from delamination effectively, and the foam core board can improve the bending strength of the whole composite plate. Stitched foam core sandwich composite has been widely used in the fields of aviation, spaceflight, automobile, ship-building and so on because of its excellent comprehensive properties, Because Vacuum Assisted Resin Transfer Molding(VARTM)has these advantages such as simple die, operate easily, less pollution, forming large size parts and so on, we can use this process to complete the resin filling of stitched foam core sandwich structure preform, and then obtain the high quality composite products.The process of resin filling of stitched foam sandwich structure composite with VARTM is studied in this paper. Experiments and simulation of the resin filling process are carried out. Optimal process parameters are obtained to provide guidance for producing high quality composite products. The corresponding research and conclusions are as follows:Firstly, stitched foam core sandwich structure preform is made and then finished resin filling with VARTM process to verify the feasibility of experiment program. Take the corresponding measures to solve filling problems encountered in the process of resin filling to improve infiltration quality.Secondly, stitched foam sandwich structure of preform model is established, and the equivalent permeability and porosity of the model are calculated, the preform resin filling process is simulated with the help of software PAM-RTM. Compared with the experimental results, simulation method can be confirmed the accuracy and reliability.Then, Based on the specific experiments and numerical simulation, the effects of distribution medium position and stitching parameters(suture pitch, row spacing, foam core board thickness, needle diameter, thickness of the fiber panel, stitching direction)on resin filling are analyzed. It is showed that a layer of distribution medium placed between the foam core plate and the lower fiber is the optimal position. The effects of stitch parameters on resin filling can be obtained by simulation, and the results can provide an important theoretical basis for producing high quality composite products.At last, reinforcing ribs are added into the middle of foam core to get stitched foam core sandwich structure preform with ribs. Experiments and simulation of the preform infiltration with VARTM process are implemented. Simulation results can be verified by Comparing with the corresponding experimental results. This will help further study for the stitched foam core sandwich structure composite with ribs.