Thermo-mechanical characterization of a carbon micro-fibre reinforced polymer for additive manufacturing in space applications

In the latest years 3D printing have taken hold in a wide range of industrial applications. This fast diffusion is especially due to its characteristics of flexible, rapid and cost-efficient production of objects which have a complex geometry, not obtainable with traditional techniques, or prototypes to be tested. These features have urged a rapid development of increasingly efficient materials in order to use additive manufacturing, not only for rapid prototyping, but also to build real industrial products. 3D printing technology has gone from producing objects for rapid prototyping using common thermoplastic polymers up to additive manufacturing techniques which use metal alloys or some special carbon and glass fibre reinforced composite materials. It is well known that in the aerospace field structural design and manufacturing are a challenge; the choice of materials is a really critic aspect; in particular the materials choice represents a crucial phase. The polymeric matrix composite materials technology, combined with the advantages of 3D printing, would represent an ideal industrial application in the aerospace sector in which the mass and cost reduction is often pursued. In particular this technology would be ideal for micro and nano-satellites for which miniaturization often requires near net shape process techniques and the mass reduction is desirable. The aim is to reduce the launch cost which represents the greater expense. In order to verify that an innovative material, such as a composite material for 3D printing, is suitable for challenging space applications, it must be tested to verify it meets the space stringent requirements. Furthermore, an experimental investigation to know its thermo-mechanical behaviour in detail is mandatory in order to determineits physical and engineering properties. The purpose of this paper is to provide a complete thermo-mechanical characterization of a carbon micro-fibres reinforced polymer for rapid prototyping. The material is produced by selective laser syntering from powders of mixed polyamide resin and carbon polyacrylonitrile micro-fibres. As the most part of composite materials, it has an anisotropic behaviour both from the mechanical and the thermal point of view. Several tests will be performed on various different samples in order to verify the outgassing requirements compliance and to determine the principal mechanical and thermal properties. A complete characterization of the material, which is already widely used in the automotive field, is needed for the exploitation of its acctractive qualities for the aerospace industry. The thermal and mechanical characterization will also allow the development of detailed mathematical model, for example for finite element analysis, in order to provide fundamental tools for thermo-mechanical designers.