The Design Of Thermal Protection Corrugated Sandwich Mixed Structure Of Composites And Metal

Composites have the advantages of light weight and high strength.In recent years,high temperature resistant resin-based composites have been developed rapidly,showing the advantage of being able to replace high-temperature metals at higher temperatures.This paper discusses the application of carbon fiber reinforced polyimide composites in thermal protection system structure.Mainly on the heat transfer analysis of composite materials,laminate bonding under high temperature and high temperature environment,the problem of laminates bolting.The first part mainly focuses on the heat transfer analysis of the bottom panel of the thermal protection system for polyimide composites,and verifies the feasibility of improving the design scheme.The second part mainly studies the stress analysis and adhesive failure analysis of single-lap joints of laminates in high temperature environment.A high temperature resistant thermoplastic polyimide-based adhesive is used to bond laminates and metal plate.The cohesive zone model was used to simulate the mechanical behavior of the adhesive layer.The single-lap tensile shear properties at different temperatures were analyzed and the effect of temperature on the shear strength of the adhesive layer was investigated.The third part mainly analyzes the single bolt connection strength and progressive damage of laminates under high temperature environment.This paper introduces the common failure modes of laminated plate bolt joints and the progressive failure analysis method of composite bolted joints.The damage mechanism of composites under high temperature environment was studied and the prediction method of the effect of temperature change on material properties was given.Using ABAQUS software to build a three-dimensional model and Hashin three-dimensional failure criteria,Writing USDFLD subroutine to achieve stiffness reduction of the material.The failure analysis of bolted joints under different temperature environment was carried out for the single-bolt single-lap and single-bolt double-lap.Analyze the variation of the distribution of stress around the hole with the direction of the fiber and the connection strength of the different ply schemes.The fourth part analyzes the thermal stress of the corrugated board bonded by the adhesive,analyzes the damage of the adhesive layer,and verifies the strength of the adhesive layer connection.The thermal analysis was performed on the bolted corrugated sandwich structure,and the influence of the fit clearance on the compression stress around the bolt hole was analyzed.It is proposed to change the shape of the bolt hole and add a spring piece at the gap to reduce the pressing stress around the hole.