Hypervelocity impacts of space debris on spacecraft happen to be in the velocity range of 7-20km/s which have enough energy to destroy the spacecraft completely. According to NASA studies till date only 6% spacecraft in the LEO region are operational while rests are danger for them. This danger becomes even more critical when human factor is involved like in case of International Space Station. Different shielding concepts especially Whipple shield has already been extensively studied analytically and experimentally. But due to the recent advancement in the field of Composites world and their superiority in terms of high strength and stiffness make them a better candidate for spacecraft shielding concept. In this work carbon-epoxy shielding system with multiple bumpers in normal and inclined combination is tested and validated. First of all carbon-epoxy laminate is being made by using CU125NS with 16 layers, 1.748mm average thickness [(0/45/90)2]s, as its been found the best for energy absorption among all available prepreg on the basis of previous experiments. After manufacturing of composite, the specimens were exposed to LEO environment with 14 thermal cycling along with atomic Oxygen, UV and high vacuum to get the proper exposure to LEO environment. During this total mass loss of 0.40% was found along with degradation in properties due to synergistic effects of LEO environment. In the end, two stage light gas gun facility was used to get the experimental profile, energy absorption and behaviour of composite. The composites bumpers were used in normal and inclined combinations by varying front and rear bumpers at predefined standoff distance. The velocity range was limited up to 1.5 km/s due to the limitation of gas gun. In the end validation was done by using commercially available software LS-DYNA. The module used in LS-DYNA was SPH (Smooth Particle Hydrodynamics) with the combination of both FE and SPH modelling. In the end, the results of double bumpers were compared with single bumpers in same and different combinations with itself and with single bumper specimens as well. It was being found that composites and especially in Normal- Inclined combinations make the shielding system more superior to Whipple shield and other concepts.
Development of Oblique angled Spacecraft Carbon-Epoxy Composite shielding system in Normal -Inclined configuration
2012
6 Seiten, 4 Bilder, 1 Tabelle, 8 Quellen
Conference paper
English
Abschirmung , CFK (carbonfaserverstärkter Kunststoff) , Einfallswinkel , Energieabsorption , Epoxide , Finite-Elemente-Methode , Geschwindigkeit , Hochfestigkeit , Hochvakuum , Hydrodynamik , Massenverringerung , Raumstation , Sauerstoff , Schichtdicke , Software , Steifigkeit , Synergieeffekt , Temperaturwechselprüfung , UV-Bestrahlung , Stoßfänger