In the aerospace industry the demand for very strong and light components is a permanent objective and for this matter composite materials began to be used at large scales in construction of space structures. The presence of micrometeoroids and orbital debris in space, particularly in the lower earth orbit, presents a continuous hazard to orbiting satellites, spacecraft, and the International Space Station. Among the 8700 objects larger than 10 cm in Earth Orbits, only about 6% are operational satellites and the remainder is space debris. Likewise, a major challenge for space missions is the material selection due to the fact that in space materials present a higher degradation rate and they are subjected to wear and structural damage, especially when facing extreme environmental conditions. In this paper, a self-healing concept embedded into a Carbon Fiber Reinforced Polymer (CFRP) composite parabolic satellite mirror is under development at COMOTI Research & Development Institute for Gas Turbines. The goal of the research is to provide a material that increases the operational life of satellites in Low Earth Orbit (LEO). The work addresses two different but interconnected fields, material science for developing a multifunctional composite material having an embedded self-healing system and aerospace field for developing a new, lightweight structure. The self-healing system under study consists in a blend of microcapsules containing variations of dicyclopentadiene (DCPD) monomers, 5-Vinyl-2-norbornene (VNB), 5-Ethylidene-2-norbornene (5E2N or ENB) and ethylene glycol dicyclopentenyl ether methacrylate (EGDP).

Influence of humid aging on tensile properties of two polymeric composites was studied. The purpose of the study was to evaluate the suitability of the materials for a naval helicopter external fuel tank. Due to the application, the humid environment was kerosene and saline solution to evaluate the sea water effect on the composite tensile strength. The composite samples were immersed in kerosene for 168 hours, respective 1752 hours and in saline solution for 168 hours. Tensile tests were performed after the immersion. The composite sample tensile tests showed that kerosene and saline solution had no influence on the elastic modulus of the materials, but it was observed a slight improvement of the tensile strength of the two polymeric composites.

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The analysis of damage resulted from concentrated out-of-plane impact forces is a concern in case of fiber reinforced polymeric composite aerostructures. Thereby, it can be quantified in terms of resulting size/damage type by drop weight impact testing. The aim of the present research was to evaluate the impact response of CFRP laminates by FEA and experimental tests. For FEA, two failure criterions were used, energetic criterion and Tsai Wu criterion. In both modeling scenarios the laminate was fractured. In case of the energetic criterion it was observed a meandering crack along with internal delamination of the material plies, while in case of the Tsai Wu criterion the impactor passes through the specimen, destroying the impacted area. Experimental tests performed at 0.7 meters height and 33 J of impact energy showed that all material plies were visible damaged, but the impactor didn’t pass through all specimen thickness. Different damage modes were observed on the tested specimens, the impacted face of the specimen presented a combined damage consisting in large cracks with fiber breakage indentation/puncture and a dent while on the non-impacted side of the specimen splits, cracks and a small swelling were observed. Considering the results from FEA and experimental tests, it can be said that regarding the damage shape, the experimental results are in a good agreement with a combination of the results obtained from the two failure models of FEA.