Characterization of nanoparticle enhanced multifunctional sandwich composites subjected to space radiation

One of the major concerns in long duration space exploration is to minimize the exposure of crew and equipment to space radiation. High energy radiation not only can be hazardous to the health but also can damage the materials and electronics. Current designs are contained heavy metals to avoid occupational hazards from radiation exposures. As a result the shielding structures are heavy and not effective to attenuate all types of radiation. Therefore, the proposed lightweight sandwich composites are designed to effectively shield high energy radiations while providing structural integrity. In the manufactured hybrid sandwich composite, High Molecular Weight Poly Ethylene (HMWPE) woven fabrics are selected as face sheets due to their advanced mechanical properties and excellent physical properties along with effective shielding properties. Basically polymers due to high hydrogen content are considered as effective materials to attenuate high energy radiations. In addition, the core material is epoxy composites incorporating three weight percentages of three different nanoparticles viz. Boron Carbide, Boron Nanopowder and Gadolinium. In fact if polymers as low Z materials are used alone, they usually are not successful to attenuate highly penetrative rays. Therefore, one solution is known to infuse polymer matrix with high radiation absorption properties nanoparticles. Among several different nanomaterials, the three aforementioned nanofillers were chosen because of their good radiation absorption properties. Gadolinium has the highest thermal neutron cross section compare to any other known element and 10B-containing materials are known as excellent radiation absorbers and the composite filled with them have the advantage of convenient and safety in construction, operation and reintegration. The sandwich composites were manufactured using Heat-Vacuum Assisted Resin Transfer Molding method (H-VARTM), which is a cost effective method for high volume production of sandwich structures. To evaluate the shielding performance of manufactured sandwich panels the neutron attenuation testing was performed. The results from neutron radiation tests show more than 99% shielding performance in all of the sandwich panels. In comparison with other nanofillers, Boron Nanopowder showed highest radiation shielding efficiency (99.64%), which can be attributed to its lowest particle size and better dispersion ability into epoxy resin. The flatwise compression testing was performed on all four sandwich panels to determine the mechanical strength of materials before and after being exposure to radiation. The results demonstrate that proposed hybrid sandwich panels can preserve their mechanical integrity while being exposed to the radiation.