Induction heat annealing of fast-cure composites for residual stress and shape distortion removal

Purpose and goal

The main goal of the project was to study feasibility of induction heating for post-curing of carbon/epoxy composites. The novel method has a high potential to significantly shorten the post-curing time and reduce residual stresses and shape distortions of composite components. The obtained results show that direct induction heating is a feasible and highly promising method for curing and post-curing of carbon fiber composites. However, the technology must be further developed to ensure a uniform heat distribution, which is at present very difficult due to material anisotropy.

Expected results and effects

The project results demonstrate the feasibility of induction-heat post-curing method for carbon fiber composites. It was also shown that induction heat post-curing is a much faster way for curing composites compared to conventional oven post-curing. It was also shown that the material anisotropy problem must be further investigated to upscale the current technology to a larger component level. Nevertheless it is expected that the present project results will initiate more research studies and promote implementation of induction heat post-curing of composites in the industry.

Planned approach and implementation

The research work was divided into three work packages. Characterization of fast-cure composites was performed obtaining the values of mechanical, thermal and electrical properties. Simulations of residual stresses, induction heating and forming were performed. Experimental validation was performed to study the effect of induction heat post-curing on the degree of cure and the residual stresses within the material. Project results proved the feasibility of the induction heat post-curing method and highlighted the challenges for further advancement of this technology.