| Customer: ESA/ESTEC (2002 – 2005) | |
 | Generation of failure criteria guidelines for the engineering of FRP and CMC structures by review of common methods and additional sample test programs. |
With respect to failure criteria of fibre reinforced plastics (FRP) a significant amount of work has already been performed by universities and industry. Many models exist and a considerable amount of test data is available. In the past, work had been performed by and for ESA with the objective to classify the available criteria and to establish guidelines for their application with respect to spacecraft design and verification. With this study it was the intention to complete that work as an integral, but small, part of this program.
The study focused also on a second material, the fibre-reinforced materials having a ceramic matrix, also called ceramic matrix composites (CMC) e.g. glass, C/C-SiC, C-C, SiC-SiC. The main attraction of these stiff materials is their capability to maintain performance at the very high temperatures that are typical for ‘hot structure’ applications, e.g. nose cap, wing leading edge and control surfaces of future re-entry vehicles and RLV. In addition, the carbon fibre reinforced glass or ceramic composites are very suitable for applications in the design of antenna’s, mirrors, platforms and other dimensionally stable structures of satellites due to the possibility to achieve a thermal expansion and environmental stability near zero!
The manufacture of these new advanced materials is extremely expensive. For future applications in structures, it is therefore cost effective to limit the amount of tests and to perform structural verification by analyses as much as is possible. However the lack of knowledge on failure criteria restricts this approach. Therefore the emphasis of this study has been on the derivation of such criteria and guidelines for their use in spacecraft design and verification for all of the material types mentioned above. For these materials the available amount of material test data (coupon tests) had been rather limited, and it had been expected that the Contractor will have to perform a limited material test program to derive relevant data, which indeed has been performed by the HPS and its subcontractors.
For both of the two material groups, FRP and CMC, it was not the intention of this study to perform basic research for developing new failure criteria, but to establish the failure criteria that are presently available, and to evaluate their practical usefulness and applicability. Here it has not only understood failure criteria in the sense of Tsai/Wu/Hill/Hoffman/Puck/Cuntze etc proposed methods, i.e. traditional quadratic or interaction models as well as more physically based criteria, but as a tool which allows us to predict failure of a component based on a user given definition of failure.
Publications:
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Statement of Work:
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