Development and validation of a flexible fiber graphene laminated heater for composite adhesive repair

Abstract

Flexible electric heaters are widely employed in the field of in-situ repair of composite structures for aircrafts. However, the existing traditional resistance wire heaters suffer from low damage tolerance, uneven heating, and high energy consumption. In this paper, a flexible Fiber Graphene Laminated heater(FGL heater) is proposed, which exhibits much better thermal efficiency in terms of heating rate, temperature uniformity, and energy consumption. The experimental results demonstrate that the traditional resistance wire heater achieves a heating rate of 0.58℃/s, with a maximum temperature difference of approximately 10℃under a 300W input power, which consumes 81.7×103J to heat from 24.6℃ to 100℃. In contrast, under the equal input power, the proposed FGL heater achieves a significantly higher heating rate of 3.8℃/s with a maximum temperature difference not exceeding 7℃. It only consumes 12.1×103J to reach the same temperature, reducing energy consumption by 85.2%. The silicone-encapsulated FGL heater also exhibits a heating rate of 1.1℃/s with a maximum temperature difference not exceeding 4℃. It consumes 45.7×103J, reducing energy consumption by 44%. Furthermore, the proposed FGL heater is capable of composite single-lap repair on the wing leading edge of aircraft, with a curing area temperature difference not exceeding 1°C.