Experimental Structural Design of a Novel Variable-Sweep Wing Based on a Four-Bar Planar Linkage.

The variable-sweep wing, as an important morphing wing technology, has received widespread attention because it can change the sweep angle according to different flight conditions. It has the advantage of simultaneously utilizing a large sweep angle to reduce shock wave drag at high speeds and improving lift characteristics at small sweep angles. However, it has always been the case that the variable-sweep wing will bring about a rearward shift of the center of gravity when the sweep angle increases, leading to a decrease in aircraft stability. This paper focuses on a structural design of a variable-sweep wing based on a four-bar planar linkage. The novel variable-sweep wing structure containing a four-bar planar linkage and an outer wing section is proposed, and key parameters are extracted to establish a mathematical model of the mechanism. Through parametric analysis, main parameters have been identified, and the structure is optimized: the longitudinal position (direction of the fuselage) of the wing's center of gravity is designed to maintain minimal change during the morphing process, but remain the same at both the beginning and ending states of the transformation. The structural design of the variable-sweep wing is carried out based on this. Then, the finite-element model is established to validate the load-bearing capacity of the variable-sweep wing and derive the driving force. Finally, as one of the main novelties, a full-size prototype is successfully manufactured for load testing. The results of finite-element simulation and load testing show that this variable-sweep wing structure can achieve movement from 30° to 70° under an aerodynamic load that is up to 460 kg/m2. The present study demonstrates the effectiveness and potential of the proposed morphing trailing edge concept for real application on aircraft. [ABSTRACT FROM AUTHOR]