Thermo-mechanical behavior of form-building equipment from composite material for reflector of spacecraft antenna

Complex shape composite parts are made using a mould having the same shape as the part. First, the material is laid upon the mould, and then it is polymerised at certain pressure and temperature that may reach 200°C. Therefore, the most significant problem of high-precision composite parts shaping is thermal distortion occurring during polymerisation. For many years, metal hybrid moulds have prevailed in high-precision composite parts manufacturing. A hybrid mould has invar (nickel alloy whose CLTE is close to zero) shaping plate and a support structure made of some other metal of good thermal conductivity. The attachment elements between the shaping plate and support structure allow their unrestricted expansion. Disadvantage of metal moulds are high cost, low material utilisation ratio and long manufacturing cycle. The next step in evolution of moulds for high-precision composite parts was the composite mould. Glass and carbon fibres are used for these moulds. Mould surface may be covered with a layer of ceramic or gel coat of precise thickness, which will minimise roughness, improve maintainability and increase allowable number of item separations from the mould. Composite moulds are free of disadvantages typical for metal moulds, but a number of design issues still remain, such as increase of rigidity and decrease thermal deformations during cure. This paper proposes a design of carbon composite mould for satellite antenna reflector. The main requirements for this mould are precision and stability of the shaping surface. Design solutions are validated by thermal and static mechanical analyses base on finite element method.