Experimental study on mechanical properties of composite with thermal protection by coating highly oriented graphite films under heating on single side
Polyimide resin-based composites have the mechanical properties of lightweight and high strength at high temperature,which have a wide application prospect of aircraft engine casings and external tuning segments.There is usually a significant difference in temperature between the two sides of this kind of thin-walled structure,there are relatively few researches on the mechanical properties of this kind of composite under the condition of high temperature on one side.This paper took the high temperature resistant carbon fiber reinforced polyimide composites laminates as the research object,and unilateral preparation of graphite film as a thermal protection system of composite materials.Composite materials specimen with two lay-up angles of[0]8 and[45/-45/0/90]2s were prepared.Longitudinal tensile and open-hole tensile tests were carried out at 25℃ and high temperature with heating on single side.The test results show that longitudinal tensile failure mode and open hole tensile failure mode at high temperatures does not show evident differences with the failure modes at room temperature.The longitudinal tensile damage mode is fiber fracture,and the open hole tensile damage mode shows matrix fracture,fiber fracture and pull-out.At the same temperature loading,the temperature of the unheated surface of the specimen with graphite film is slightly lower,compared with composites without graphite film.The thermal protection properties of graphite film does not produce significant enhancement effect on the longitudinal tensile strength,which is mainly dependent on the fiber bearing.For the open hole tensile strength,which depends on both the fiber and matrix,there is a significant increase in the bearing capacity at the higher temperature.
polyimidegraphite filmcomposite materialthermal protection systemheating on single side
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