Study And Application Of VARTM On Wind-power Electricity Generating Shield Sandwich Composites

Recently, advanced composites have been applied in most high-tech fields as wind-power electricity generating and aerospace with its advanced performances. Compared with metal composites, the fiber reinforced composites have a lot of advantages: they are anti-rusty, pollution-free, have light weight and can be easily designed.With the development of science and technology, the technology used in the composite had been developed increasingly, from the simple hand lay-up to RTM,VARTM,SCRIMP,RFI and others technologies. The popular technology overseas-Vacuum Assisted Resin Transfer Molding (VARTM) was studied in this thesis. VARTM process is a variant of vacuum-infusion resin transfer molding (RTM) in which one of the solid tool and faces is replaced by a flexible polymeric film. This process or a modified version has also been called vacuum infusion or SCRIMP. The VARTM process is a very clean and economical manufacturing method, the process draws resin into a dry reinforcement on vacuum bagged tool, using only the partial vacuum to drive the resin. Compared with hand lay-up and other large-part manufacturing processes, this process enhances the component mechanical properties and fiber content by reducing void percentage.This thesis also focuses on the VARTM technology applied on the sandwich composite which used in the wind power shield. Firstly we simulated the experiment on the lab and determined the VARTM procedure, tested different resin gelation time, compared different resin抯 flow and permeability in the sandwich composites and compared different resin抯flow and permeability in the fiber composites, made comparison among different sandwich structure, then adjusted the experiment method, chose the proper lay-up method and resin, sandwich structure. By doing this, resin flow could be well controlled in the mold infusion.At the same time, the flexural performance and compression performance were tested, and the acoustic emission technology was employed to analyze the failure factors and feedback to the previous experiment.At last, the wind power shield was manufactured according to the. reinforcement fiber, resin, lay-up and the sandwich structure determined in lab and through analysis in composite performance, the wind power shield was successfully manufactured.