A variable stiffness morphing skin: preparation and properties
Xiaoming Ren, Guangming Zhu
Abstract
Abstract In the course of flight, morphing skins play an important role in morphing aircrafts. Shape memory polymer (SMP) with variable stiffness performance is a good candidate material for skin. In this paper, a series of SMP morphing skins were prepared from hydro-epoxy resin, carboxyl-terminated butadiene acrylonitrile (CTBN) and maleic anhydride. By adjusting molecular weight and content of CTBN, in-plane properties and out-of-plane properties of morphing skins can be adjusted. Due to the in-plane tensile stress acting on the skin during flight, tensile test was carried out to study its in-plane performance. After testing, skin can resist maximum in-plane tensile strength of 63.7 MPa. As for the out-of-plane performance of the skin, shape memory test was studied in this paper. All morphing skins have 100% shape fixity rate (Rf) and fast shape recovery rate (Rr). When toughened by CTBN of 10% of 4000 molecular weight with a mass fraction, the skin can recover its out-of-plane deformed shape in 33 s. The SMP skins were proved to be a promising candidate for morphing skins.