Research on a variable camber wing with shape memory polymer skin

Morphing aircrafts obtain more flight performances in the whole envelope by changing the wing shape, which provide to accomplish more missions under different flight conditions. There are many key technologies to realize the concept of morphing aircraft. As one of the primary challenges, morphing skin should not only have enough stiffness to withstand the aerodynamic loading, but also alter shape with the morphing structures. Variable stiffness materials are needed to solve this problem. As a typical variable stiffness material, Shape Memory Polymer (SMP) could well meet the demotion of morphing skin. The SMP's stiffness is controlled by the temperature of the material. SMP is stiff in low temperature; it becomes flexible after heating over the glass transition temperature (Tg); when cooling below the Tg, the material returns to stiff again. The mechanical properties of the pure SMP can be improved by mixing into some filler forming Shape Memory Polymer Composites (SMPCs), such as spandex fibers, carbon fibers, carbon nanotube, etc. In this work, a variable camber morphing wing with spandex fibers enhanced SMPCs skin was designed and manufactured. The aerodynamic loading and the out-of-plane deflection of the SMPCs skin were simulated. A uniformly distributed load, which was the maximum pressure of the skin obtained from FEM, was applied to the skin to measure the deflection of the SMPCs skin. The infrared thermometry of the SMPCs skin was discussed. Results shown that the SMPCs could be served as a choose for a morphing wing structure.