Improvement and evaluation of polymer-matrix composite panels with hat stiffeners

Hat-stiffened composite panels fabricated by co-curing technologies are widely used in the fuselage panel due to the good structural stability and high efficiency of axial load transferring. The bonding capability between the stiffener and skin is a primary criterion to assess the co-curing quality. In this paper, two reinforcement technologies of filling filler in the triangle region and adding split-stopping tape between the stiffener and skin were employed to improve the bonding capability. Effect of filler and split-stopping tape on the interface strength was analyzed, and the optimal size range of the filler and split-stopping tape were obtained. To improve the universality of application for the two reinforcement techniques, the filling coefficient of 0.62~0.77 and the split-stopping tape width coefficient of 0.56~0.67 were obtained by calculation. Results of the study can be used to develop other kinds of stiffened panels and will ultimately lead to optimized skin/stiffener designs.