Load-bearing capacity of bar termination ends of reverse curvature reinforced wall panels

Modern high-performance fighter aircraft are affected by the overall arrangement, and many anti-curved surfaces often appear in the fuselage shape. When the anti-curved reinforced wall panels are subjected to out-of-plane bending loads, there is an obvious tendency of peeling between the termination ends of the bars and the skin, which is further exacerbated by the geometrical characteristics of the anti-curved surfaces. The sudden change in structural stiffness at the termination end of the bars leads to a significant stress concentration phenomenon, which in turn triggers the debonding problem between the bar-skin interface, resulting in a reduction of the initial damage load of the structure. Six different design configurations of the termination end of the bar of a reverse curvature reinforced wall panels are proposed, and four-point bending loading tests are carried out. The results show that the use of end isolation at the termination end of the bar of a left-reinforced wall panel can reduce the sensitivity of the structural process, improve the initial damage load by about 20%, and reduce the dispersion of the load. The addition of a base plate near the termination end of the bar or the thickening of the L-legs significantly can improve the ultimate damage load by 39.78% and 58.28% respectively.