Designing a variable camber wing trailing edge with initially curved beams

In recent years, variable camber wings (VCWs) have gained significant attention worldwide because of their advantages in improving fuel efficiency, reducing turbulence, and providing an adjustable lift-to-drag ratio for future aircraft. Although many attempts have been made to design the structure of VCWs, the design of VCWs with large deformations and high loading capacities remains lacking. This study proposes a novel method for designing VCWs by applying initially curved beams (ICBs). Through a compliance analysis of ICBs versus straight beams, it is evident that ICBs provide a more comprehensive compliance range than straight beams. Utilizing the compliance properties of ICBs, a VCW trailing edge (TE) structure was proposed and parameterized. To minimize deformation errors and post-deformation stress, finite element models were established, and a genetic algorithm was employed to optimize the cross-sectional geometry and dimensions. An optimized cross-sectional TE prototype was fabricated. Subsequently, experiments on the variable camber, digital image correlation (DIC), and load bearing were conducted to validate the function of the variable camber, measure the stress level, and assess the load-bearing capacity. The experimental results were consistent with those of the simulations. The 5 cm-wide TE prototype achieved the variable camber range of ±25° with a maximum stress of 243 MPa along with notable deformation accuracy. It has a static load capacity of 10 kg. These results confirmed the feasibility of designing VCWs capable of large deformations and high loading capacities, utilizing ICBs.