Mechanical performance of stiffened CFRP panel cured via magnetic particle-induced in-situ heating

With the development trend of large and complexity of carbon fiber reinforced polymer (CFRP) structures, the conventional oven or autoclave molding method exposes problems such as size limitation, long fabrication time, low energy utilization, uneven curing, etc., and there is an urgent need to explore new composite molding method. In this paper, a new fabrication method to cure CFRP based on electromagnetic induction in-situ heating was investigated by using Mn-Zn ferrite as a heating carrier. The heating characteristics, mechanical properties and porosity of stiffened CFRP panels with two kinds of complex layups, T-shape and I-shape, were investigated, and comparative analyses were carried out with the counterpart specimens cured by an oven. The results show that the induction method can achieve in-situ, uniform, temperature-controlled and lay-up angle independent heating and curing for both two types panels. Under the condition of 13 wt% Mn-Zn ferrite addition and 5.5 hours induction heating, the flexural stiffness of the T-shaped panel is increased by 5.2% and the maximum load is increased by 11.2% compared to the oven-formed specimen under the same curing time. The buckling load of the I-beam reinforced panel increases by 3.3% compared to the oven-molded specimen. However, the porosity of the two types of panels increase slightly by 0.4% and 0.3%. The results obtained in this paper provide important guidance for the engineering application of electromagnetic induction curing process in the fabrication of CFRP composite structures.