Research On Properties Of Electrically Heated Composites Based On Weft-knitted Axial Fabrics

Aircraft flying in the icing weather conditions will cause the rotor leading edge or engine intake system icing,which problems will not only cause the aircraft flight efficiency decline,but also can cause flight accidents.Therefore,in order to meet the requirements of all-weather flight of aircraft and flight in special environment,it is urgent to provide reasonable and effective anti-deicing protection for rotor leading edge,engine intake system and other parts.Therefore,electrically-heated fabric and its composites are the first choice of electrically heated anti-deicing technology.In order to develop a kind of new electric heating composite is expected to be used for aerospace anti/deicing protection,subject depend on weft knitted biaxial fabric(WKBF)have a good deformation features,developed a kind of WKBF/epoxy resin composite based on it,its on the lower level are made of glass fiber/epoxy resin prepreg,the middle layer using copper and nickel alloy wire as the electrically heated fabric with warp line,fabric bundles and lining weft yarn of polyester fiber and glass fiber respectively.Firstly,three kinds of weft knitting biaxial electrically heated fabrics with different density of resistance wires were prepared by transforming the function of lining-bed transversal movement and the pressing function of knitting needle heel.On this basis,a vacuum bag forming process was designed to prepare electrically heated epoxy composites.The tensile properties of raw materials and electrically heated fabrics were tested.In particular,in order to objectively temperature characteristics,the matrix and reinforcement interfaces strength of electrically heated composites,using experimental method to study the influence of resistance wire density in WKBF to electric properties and interlaminar shear properties of the composites.To accumulate performance data for the development of electrically heated composites for aerospace anti/deicing protection.Obtain the following conclusion:(1)The uniaxial tensile strength of electrically heated fabrics is proportional to the arrangement density of resistance wires.Compared with the fabric with the arrangement density of resistance wires of 3 yarns/cm,the tensile strength of electrically heated fabrics with the arrangement density of 4 yarns/cm and 7 yarns/cm is increased by 11.66%and 43.18%,respectively.(2)The uniaxial tensile strength of the electrically heated composites is proportional to the density of the resistance wires,and the tensile strength is increased by 13.52%and 26.44%,respectively.The interlaminar shear strength of electrically heated composite material is inversely proportional to the density of resistance wire arrangement,which decreases by 33%and 54.38%respectively.(3)Under the same test conditions,the highest equilibrium temperature of the composite surface is proportional to the applied voltage.When different composite apply the same external voltage,the lower the density of the resistance wire arrangement is,the higher the maximum equilibrium temperature can be achieved on the composite surface.When the applied voltage is2V.The highest surface equilibrium temperature of the three composite to 88.85℃、84.98℃、72.04℃ respectively,and the surface temperature distribution of composites is uniform.