Experimental investigations on structural improvement of morphing mechanism for nose cone of aerospace vehicle adopting a bionic redundant constraint strategy

Aerospace vehicles have recently received great attention for their completely reusable in aviation and aerospace. To achieve the optimal aerodynamic performance of the aerospace vehicle, the nose cone needs to change its aerodynamic shape under different flight conditions. However, the structural design of a morphing nose cone that is capable of changing aerodynamic shape adaptively and withstanding prescribed aerodynamic loads remains an ongoing challenge. To overcome this issue and to further advance our previous work, the motion performance of a morphing nose cone inspired by the deformation mechanism of the honeybee abdomen was tested to evaluate the deformation ability and bearing capacity. The dynamic prediction analysis of the morphing nose cone with a clearance joint and flexible links was then investigated to elucidate the crucial issues in the deformation movement. To improve the motion performance, a performance improvement scheme based on redundant constraints drawn from the muscle distribution of the honeybee abdomen was proposed. Finally, the structural stiffness, dynamic analysis, and experimental testing of the improved morphing nose cone were conducted. The experimental results indicate that the extension and contraction ratios and bending angles of the improved morphing nose cone under loads of 0, 10, and 25 kg loads improve by 1.51% and 2.329 degrees, 2.78% and -1.902 degrees, and 5.06% and 1.111 degrees, respectively, verifying the rationality and effectiveness of the performance improvement scheme. This work provides a new reference for the design of the morphing structure for aerospace vehicles.