The design of continuous carbon fiber composite honeycombs and study on its properties

A lot of researches on continuous carbon-fiber composite laminates have been conducted, but no scrutiny has been devoted to continuous carbon-fiber composite honeycomb sandwiches. This paper is aimed to assess the design and properties aspects of honeycomb sandwiches made of continuous carbon-fiber composite laminates. The applicability of the existing theoretical formulas for the mechanical properties of isotropic material honeycomb sandwich on continuous carbon-fiber composite honeycomb is examined by comparing the obtained results from the finite-element modeling and experimental results. The results reveal that the theoretical formulas of isotropic material honeycomb sandwich in density and out-of-plane compressive elastic modulus are suitable for continuous carbon-fiber composite honeycomb, while other performances cannot be achieved by theoretical formulas of isotropic material honeycomb sandwiches. The out-of-plane compression and shear properties of continuous carbon-fiber composite honeycomb can be evaluated by finite-element modeling. The effects of cell side length, wall thickness, and 45° ply content on the honeycomb density, out-of-plane compression properties and out-of-plane shear strength are researched. Subsequently, the out-of-plane compression experiments of honeycomb are carried out to show the accuracy of the finite-element modeling. Finally, a design approach for continuous carbon-fiber composites honeycomb structures is proposed. This methodology results in the design of honeycomb sandwiches with better performances. The chief innovation of this paper is to develop the concept of continuous carbon-fiber composite honeycomb sandwich structures. To this end, a honeycomb structure finite-element model of continuous carbon-fiber composite is established, and the mechanical properties of continuous carbon-fiber composite honeycomb sandwiches are explored. A methodology for the rapid design of honeycomb size parameters of continuous carbon fiber composite honeycomb sandwich is also proposed.