CONDUCTOR · Flexible Conductive Composite Repair Heaters

Appropriate curing of the patch resin and the adhesive layer is an essential step to secure the integrity and the sound mechanical performance of a bonded composite repair. Today, the required elevation of temperature is usually achieved by means of resistance heating blankets, which conduct heat to the repair area, regulated through closed loop temperature control, using one or two spot temperature measurements. Even though this method is rather simple and works adequately for small repairs, when larger areas need to be heated, discrepancies, like cold or hot spots, frequently occur, due to variable heat losses, caused by geometrical asymmetry, “heat sinks” etc. The scope of this proposal, further to the know-how of the proposing Consortium in conventional resistance heating and induction heating, is to develop a third heating method called Conductive Skin Heating (CSH). The main advantages of CSH are that the voltage and the current could be very low compared to heat mats because of the very good efficiency of this middle frequency heating, which will be about 50 Hz to 20 kHz. Similarly, the voltage range could be limited between 5 to 100 V, which means that the maximum current in the mat will be less than 100 A, depending on the application and the heating rates which need to be achieved. Consequently, the CSH-mats could be much cheaper, while the electrical danger for the operators and any peripherical electronic devices will be significantly reduced. Additionally, as this method allows heating of very thin foils, the CSH-mats will be very flexible and easy to adapt to complex 3Dgeometries, while they could be easily integrated into the vacuum bag. Consequently, the handling of this thin and lightweight CSH-mats will be much easier compared to the other heating systems used for FRP repair, like thermal blanket and induction heating.""