Integrity control for high temperature structural applications

High temperature composite materials in combination with advanced design and manufacturing concepts are becoming more and more important for space transportation systems like hypersonic flight and reusable reentry vehicles. In order to meet the challenging demands for thermostructural applications Carbon/-Carbon and Ceramic Matrix Composites are the most promising materials with respect to weight, stiffness, strength and heat resistance. An ESA supported study has been undertaken to define an Integrity Control Methodology for thermostructural elements made from these high temperature composite materials

Universal adjustable mould Executive summary

The feasibility of an adjustable mould tool for solid antenna reflector dishes for space application is part of the Advanced Systems and Technology Program (ASTP), Phase 3. For ground station antennas an adjustable mould called 'Bed of Nails' concept, has already been successfully applied. Objective of the reporter study was to investigate a concept to produce solid reflectors with different shapes for space application with very good surface accuracy. The adjustable mould should be used for curing composite materials by autoclave treatment under heat and pressure. The results of the concept selection investigation was the bed of nails concept together with a thermoplast mould skin. Backed by creep behaviour tests of the thermoplast and trials on the model mould, the appropriate parameters were found to form the thermoplast mould skin over the contour-giving nailheads. Once formed at a temperature of around 200 C, the mould skin remains stable during the reflector curing process. The design of the real adjustable mould (see figure below) was updated according to the results of the trials and the mechanical and thermal analyses of the mould. Summing up the results of the trials with the model mould was found that requirement for the contour accuracy can be fully met. The RMS-values of the formed thermoplast mould skin were between 20 and 40 #mu#m and for the elegant breadboard reflector panel less than 44 #mu#m. (orig./RHM)Available from TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEEuropean Space Agency (ESA), 75 - Paris (France)DEGerman

Bauweisen fuer neue Verbundwerkstoffe BFNV Endbericht

For future re-entry vehicles and high-precision mirrors the application of fibre reinforced ceramic is necessary. For a reusable load-carrying heat shield and for a hot mirror, investigations of design concepts led to the application of cost efficient manufacturing and assembling methods for fibre reinforced ceramics. For a heat shield C/C- and C/SiC-panels were manufactured and thermomechanical analysis and high-temperature test on joining elements confirmed the feasibility of the chosen design concepts. (orig.)Bei zukuenftigen Raumfahrtstrukturen wie z.B. Wiedereintrittskoerper, wiederverwendbare Raketenteile und Spiegel ist der Einsatz von neuen Bauweisen erforderlich. Diese Strukturen muessen neben mechanischen Lasten hohe Temperaturen ueber 1000 C standhalten. Als Materialien kommen vorrangig Verbundwerkstoffe aus keramischen Fasern und Harzen (CMC) sowie kohlenfaserverstaerkte Kohlenstoffe (C/C) in Frage. Die Studie setzte sich zum Ziel Bauweisen unter Beachtung geeigneter Rechenmodelle und Fertigungsverfahren fuer ein wiederverwendbares Hitzeschild und einen hochgenauen Spiegel zu entwickeln. Es wurden Bauweisen konstruiert, berechnet und die Machbarkeit anhand von Einzelelementen nachgewiesen. Hochtemperaturtests aus Fertigungselementen und Materialproben bestaetigen ebenfalls eine Durchfuehrbarkeit der gewaehlten heissen Strukturen. (orig.)Available from TIB Hannover: F94B862 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Bauweisen fuer neue Verbundwerkstoffe BFNV Endbericht

For future re-entry vehicles and high-precision mirrors the application of fibre reinforced ceramic is necessary. For a reusable load-carrying heat shield and for a hot mirror, investigations of design concepts led to the application of cost efficient manufacturing and assembling methods for fibre reinforced ceramics. For a heat shield C/C- and C/SiC-panels were manufactured and thermomechanical analysis and high-temperature test on joining elements confirmed the feasibility of the chosen design concepts. (orig.)Bei zukuenftigen Raumfahrtstrukturen wie z.B. Wiedereintrittskoerper, wiederverwendbare Raketenteile und Spiegel ist der Einsatz von neuen Bauweisen erforderlich. Diese Strukturen muessen neben mechanischen Lasten hohe Temperaturen ueber 1000 C standhalten. Als Materialien kommen vorrangig Verbundwerkstoffe aus keramischen Fasern und Harzen (CMC) sowie kohlenfaserverstaerkte Kohlenstoffe (C/C) in Frage. Die Studie setzte sich zum Ziel Bauweisen unter Beachtung geeigneter Rechenmodelle und Fertigungsverfahren fuer ein wiederverwendbares Hitzeschild und einen hochgenauen Spiegel zu entwickeln. Es wurden Bauweisen konstruiert, berechnet und die Machbarkeit anhand von Einzelelementen nachgewiesen. Hochtemperaturtests aus Fertigungselementen und Materialproben bestaetigen ebenfalls eine Durchfuehrbarkeit der gewaehlten heissen Strukturen. (orig.)Available from TIB Hannover: F94B862 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman