Study On Mechanical Properties Of C_f /SiC Corrugated-core Sandwich Composite Under High Temperature

Based on the excellent mechanical properties,structure of corrugated-core sandwich have been widely applied in many fields.Most of corrugated-core sandwichs are produced with wood, metal, bamboo and so on. The ceramics based composite materials made of carbon fiber have excellent mechanical properties,such as high aspect ratio stiffness, high strength and toughness, highenergy absorbing properties, sound-absorbing, shocking absorption,electromagnetic shielding.Meanwhile laying heat tube or heat insulation cloth in the hole of corrugated-core sandwichs makes the structure increase a lot of features. So It is an excellent performance multi-function engineering materials. C/Si C corrugated-core sandwich composite depending on the powerful advantage of structure and function "integration", has become the ideal material of aviation high-speed aircraft research and development. But the little research works focused on the mechanical properties of C/Si C composite corrugated-core sandwich structures under high temperature.In this paper, a PIP method was suggested to fabricate carbon fiber reinforced corrugated-core sandwich structures. The mechanical properties of C/Si C composite sandwich structures were investigated at room and high temperature, respectively. Under room treatment condition,Scientific analysis was proposed for the failure mode in compression and 3-point bending test. Calculate the strength and stiffness of corrugated-core sandwich composite structure.Meanwhile,The numerical model of the corrugated-core sandwich structures was established based on the actual structure. Simulate deformation and failure mode of corrugated sandwich structure under the effect of compression and bending load according to avtual boundary conditions and load condition. And compared the simulation and experimental analysis, further elaborated failure mechanism of corrugated sandwich under the effect of compression and bending load.High temperature condition is divided into two cases,compression and bending test under high temperature and vacuum environment and compression and bending test after high temperature oxidation. And each case can be divided into two cases,temperature 1200 ℃ and 1600 ℃. Scientific analysis was proposed for the failure mode in compression and 3-point bending test.Scanning of the surface and the cross section of the panel, core and fracture by electron microscopy(SEM), detected of materials phase change at high temperatures by X-ray diffraction(XRD).Using Raman spectrometer and infrared spectrum analyzer to analyze material functional groups change under the environment of high temperature.The mechanical properties model predicting of the corrugated sandwich structures was established based on the periodic unit cell. The theoretical analytical formulas of equivalent stiffness and equivalent strength were derived.The theoretical values of stiffness and strength were calculated using the basic mechanical parameters of the core and the panel. Theoretical and experimental values were compared, analyzing the reasons for errors.