复合材料柔性电热膜固化方法与温度分布

为解决大型整体化复合材料构件制备的低成本固化问题,采用真空灌注(VARI)成型工艺制备碳纤维/环氧复合材料层合板,发展了一种柔性电热膜(FEHF)固化方法.考察了电热膜的铺放方式、温度制度对复合材料固化温度分布规律和固化程度的影响.结果表明:电热膜拼接铺覆方法温度均匀性最佳,恒温阶段最大温差为11℃,分别比搭接铺覆和间隔铺覆降低了26.7%和38.9%.增加恒温平台有利于减小升温过程中的复合材料不同位置处的温度差异,但最终的温差和温度分布规律与未增加恒温平台相同.采用电热膜拼接铺覆方法制备了大尺寸整体化碳纤维/环氧复合材料天线反射器蒙皮,玻璃化转变温度达到80℃以上,反射器精度达到0.7 mm(r.m.s.),说明电热膜固化方法可用于大型复合材料构件的制备.

Curing method and temperature distribution of composites based on flexible electric heating film

Low-cost curing is a challenging task for composite manufacturing, especially for large-scale part. Vacuum assisted resin infusion (VARI) molding process was employed to fabricate carbon fiber/epoxy composite laminate. A curing method using flexible electric heating film (FEHF) was developed. The effects of lay-up type of FEHF and temperature cycle on the uniformity of temperature and curing degree of composite were studied. The results show that splicing overlaying FEHF has the most uniform temperature distribution with 11℃ maximum temperature difference at constant temperature stage. The temperature uniformity is improved by 26.7% and 38.9% compared to the cases using overlapping overlaying and interval overlaying FEHF, respectively. In addition, adding isothermal temperature platform is useful to reduce temperature difference during heating process, but the final temperature difference and distribution are the same as the case without adding isothermal temperature platform. By means of splicing overlaying FEHF, large antenna carbon fiber/epoxy composite reflector skin was fabricated, and the glass transition temperature of the reflector skin is over 80℃, and the reflector tolerance is 0.7 mm (r.m.s.). It demonstrates that FEHF is a feasible way for curing large composite part.