CRYOGENIC THERMAL EXPANSION PROPERTIES OF CARBON FIBER REINFORCED COMPOSITES

摘要

Due to the superior structural performance, fiber reinforced composites have been paid attentionas the candidate materials for cryogenic storage tanks in the aerospace and LNG transportapplications. Therefore thermal expansion properties of composite materials should be wellcharacterized at the cryogenic environment and precise numerical approaches are required for thestructural design. In this work, we developed an experimental apparatus to measure thecoefficient of thermal expansion (CTE) utilizing the Gifford-Mcmahon (G-M) type cryocoolerand strain gauge. At cryogenic temperature, cryogenic thermal expansion properties of carbonfiber reinforced composites were measured for the in-plane and through-the-thickness directions.As an experimental result, the in-plane CTE was measured as 4.4×10(-6)/°C and the through-thethicknessCTE was measured as 57.1×10~(-6)/°C which is larger than the CTE of pure epoxy resin(40.4×10~(-6)/°C). To explain this anisotropic behavior, a simple analytical model was suggestedconsidering kinematic constraints between the unit cells. The calculation result showed thesimilar CTE values with the experimental ones and the anisotropic behavior by geometricalconstraints of the laminated structure.