Dissertation > Aviation, aerospace > Aerospace ( Astronauts ) > Space instrument,spacecraft devices,spacecraft guidance and control > Protection, life-saving technology and equipment > Protective equipment

Thermal-structure Coupled Computer Simulation of Multilayer Protection/Insulation System

Author LiJianFeng
Tutor YeFeng
School Harbin Institute of Technology
Course Materials Engineering
Keywords Insulation structure Thermal analysize Thermal stress Finite elementanalysis Optimization design
CLC V445.1
Type Master's thesis
Year 2012
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Ceramic protection/insulation structure is the traditional structure of thermalprotection/insulation for spacecraft. it has a light weight, good insulation performanceadvantages. For the ceramic protected/insulated structure, under the premise of meet theinsulation, to improve the strength is the problem that needs to solve,and it is therequirement of integrated thermal protection/insulation structure(TPIS). Ceramic TPISconsists of two parts mostly:ceramic thermal protection stucture and porous materailinsulation structure.Between the protection and insulation structure is a air layer.it needsconnecting structure. The structure reliability and heat insulation ability are what weneed to consider.This paper,against to the large area ceramic multilayer insulated bodies,uses ANSYS software to do the thermal-stress coupling analysis and obtain thetemperature field and stress field distribution of the structure.The proof of good thermalinsulation ability and structure reliability was gived,and the thickness of thermalinsulation layer was optimized,it has some guidance on the engineering applications.Firstly, we established the multipayer insulation structure model and determinedthe boundary conditions and loads under the work conditions.The model has threelayers:thermal protection layer,heat insulation layer and body layer.There hasconnections between thermal protection and insulation layers.The load is temperaturefrom the real reentry thermal-pressure load condition TPIS.The boundary needs toconsider the reflection and convection.The finite element analysis software ANSYS was used to study the temperatureand stress field of the ceramic multilayer protection/insulation structure in thethermal-stress coupling. To consider the radiation joins, so building a complete model ofthe structure. The whole mesh and encrypted connection. Directly Coupled Method wasused for thermal coupling analysis. Adopted by the spacecraft re-entry temperature ofthe actual load to simplify the load to establish the complete structure of the model,simulate and analyze the structure of the temperature field, stress field. Final validationof this study ceramic multilayer protection/insulation system to meet the requirements,the final temperature of the insulation on the back was only50°C; maximum stress ofthe heat-resistant layer is185.6MPa,less than the silicon nitride material tensile strengthof200MPa,maximum stress of the insulation layer is less than6MPa for enhanced silicaairgel materials, fully able to meet the requirements; connection has a maximum stressof600MPa, occurred in the connectors and heat-resistant layer contact at the angleposition.Protection/insulation structure of the overall displacement field is obtained gapamount of ceramic multilayer protection/insulation and other structures used inconjunction with the reserve, in three directions, set aside the amount of X=0.72mm, Y =0.471mm, Z=0.54mm.Finite element analysis software ANSYS optimization design module wasintroduced.Using the module on protection/insulation system insulation layer and thesubstrate thickness has been optimized in the insulation layer thickness of25.1mm, thesubstrate thickness of2.75mm, the insulation layer on the back of temperature of143.5°C, less than the matrix aluminum alloy that can withstand temperatures.

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