Research On Microwave Curing Of Aircraft Composites

Compared to the autoclave curing of composites, the microwave curing of composites has the advantages of short manufacturing time, high curing efficiency and more homogeneous temperature distribution. Associated with the Natural Science Foundation project and the demand from the aerospace industry and considering the immature status of the composites microwave curing technology, this paper studied the microwave curing process of composites, which aimed at laying the theoretical and technological foundations for the application of this technology in the aerospace sector. The main achievements of this paper are listed as follow:1) A survey was conducted in some domestic aerospace enterprises to get the information of the status quo of composites manufacturing, the engineers’ acknowledgement of microwave curing technology and their viewpoints of the strengths and foreseeable problems of this technology. On the basis of the knowledge of the demand from the industry, two research topics were selected to be elaborated in this paper which was linked to the mechanisms of microwave curing and the relationships between quality and efficiency of this manufacturing technology.2) A temperature field analysis model of microwave curing of carbon fiber reinforced composites was established. Several physical mechanisms was considered in this model, including the microwave heating, the attenuation of microwave energy in the multiphase composites, the exothermal heating of the resin, the heat transfer in the anisotropic composite laminates and the thermal and electromagnetic effects of the mold and bagging materials at the boundaries. And the macroscopic material properties were calculated from the easily available material properties of fiber and resin by the multiscale homogenization method without measurements, which made the model easy to use. The simulation results fit quite well with the experimental outcomes.3) The effect of different temperature profiles on the mechanical properties microwave cured composites was experimentally studied. The comparisons were made between microwave cured and thermal cured composites with the same temperature profiles. And the tensile, compressive, interlaminar shear and flexural strengths of composites cured with different temperature profiles of various heating rates and holding time were deeply studied. The results of these experiments could serve for the guidance of the future design of the microwave curing processes.