Preparation And Properties Of Silicone Rubber Flexible Skin Material For Moprphing Wing

Morphing aircraft can realize the whole scene optimization of fuselage structure through structure or material design,which greatly expands the functionality of aircraft and improves the flight efficiency of aircraft.Nowadays,the research of morphing aircraft mainly focuses on deformable wings,while the traditional aluminum skin can’t meet the requirements of large deformation.Therefore,flexible skin materials which can meet the large-scale deformation of wings and work stably in high-speed and high-temperature environment become the key to the research of deformable wings.In this paper,the in-plane shear deformation of silicone rubber is taken as the application background,and the pretension loading method is adopted to solve the problem of bulge and fold during diagonal tension.The application of silicone rubber in the direction of deformed wing skin was studied,which provides a variety of solutions for different types of flexible skin covering materials.The effects of curing agents on the properties of silicone rubber at room temperature and high temperature were studied;methylphenyl silicone rubber skin was synthesized,and its deformation rule on deformation structural unit was studied.In this paper,the pretension loading of silicone rubber on the deformed structural element is calculated theoretically,to achieve change ± 45° with no folds and bulges in the process,0.5 times of the preformed variable should be applied,and the minimum elongation at break of silicone rubber should be 300%.Then,taking methyl silicone rubber as the research object,the effects of curing agent type and addition amount on the elasticity,mechanical properties,tearing properties and creep of silicone rubber at room temperature and high temperature were studied.When the SiH / Si-Vi ratio is 3.2,the silicone rubber has better comprehensive properties,the elongation at break is 1100%,the breaking strength is 6.85 MPa,the tear strength is36 k N/m,and the maximum deformation can meet the requirements of 300% at 250 ℃,the tensile strength is 1.35 MPa.After that,the methylphenyl silicone rubber with different phenyl content were prepared by anionic polymerization,and characterized by FT-IR,NMR and TG.The results show that the introduction of the functional groups of phenyl improves the thermal stability of silicone rubber,and the elastic and mechanical properties of the rubber were tested and characterized at room temperature and high temperature.The results show that the required 300% shape variable can be met at 270 ℃ when the content of benzene is 30%,and the tensile strength is 3.27 MPa.Finally,the structural deformation unit was used to carry out the tensile test of the silicone rubber skin.When 60% of the preform was applied to the silicone rubber,30-50 times of large angle(45°)tests could be carried out at room temperature,150 ℃,200 ℃ and250 ℃,the deformation still keeps the surface smooth without wrinkle and bulge.