Structural CNT Composites Part II: Assessment of CNT Yarns as Reinforcement for Composite Overwrapped Pressure Vessels

摘要

Carbon nanotubes (CNTs) are one-dimensional nanomaterials with outstandingrnelectrical and thermal conductivities and mechanical properties. This combination ofrnproperties offers routes to enable lightweight structural aerospace components. Recentrnadvances in the manufacturing of CNTs have made bulk forms such as yarns, tapesrnand sheets available in commercial quantities to permit the evaluation of thesernmaterials for aerospace use, where the superior tensile properties of CNT compositesrncan be exploited in tension dominated applications such as composite overwrappedrnpressure vessels (COPVs). To investigate their utility in this application, aluminumrnrings were overwrapped with thermoset/CNT yarn composite and their mechanicalrnproperties measured. CNT composite overwrap characteristics such as processingrnmethod, CNT/resin ratio, and applied tension during CNT yarn winding were varied torndetermine their effects on the mechanical performance of the CNT compositernoverwrapped Al rings (CCOARs). Mechanical properties of the CCOARs werernmeasured under static and cyclic loads at room, elevated, and cryogenic temperaturesrnto evaluate their mechanical performance relative to bare Al rings. At roomrntemperature, the breaking load of CCOARs with a 10.8% additional weight due to thernCNT yarn/thermoset overwrap increased by over 200% compared to the bare Al ring.rnThe quality of the wound CNT composites was also investigated using x-rayrncomputed tomography.