The Analysis Of Mechanical Properties Of Morphing Honeycomb Structures

Honeycomb structures are porous solid materials of a lightweight, versatile,wide range of application, and can be used in many fields. Chiral honeycombstructures (Chiral Honeycomb) is a new type of honeycomb structures in recentyears development, with excellent mechanical properties, which can realize thein-plane morphing, and higher out-of-plane stiffness properties. It can be used insmart structures and morphing aircrafts, which has tremendous developmentpotential in the field of aerospace.The Poisson’s ratio of the traditional cellular structures is positive in thegeneral, which unable to meet the needs of the development of science andtechnology. At present, the researchers turned to honeycomb structures which canrealize multi-function. The Poisson’s ratio of chiral honeycomb structure can benegative and can realize different negative Poisson’s ratio. By optimizing theparameters, chiral honeycomb structure can simultaneously realize morphing,lightweight, high specific stiffness and negative Poisson’s ratio.The paper introduces a negative Poisson’s ratio of honeycomb structure,development and research status of material and honeycomb, expounds the basictheory of chiral honeycomb structure. Successful to derive in-plane Young’smodulus, Poisson’s ratio, out-of plane Young’s modulus and the up bound oftransverse shear modulus of chiral honeycomb with four ligaments (TetrachiralHoneycomb). Homogenization method of the finite element is adopted fortetrachiral honeycomb to calculate and predict the elastic modulus and Poisson’sratio of chiral honeycomb structure, and with theories and experiments on thecomprehensive comparison. Tetrachiral honeycomb with relation to the change ofmechanical properties of chiral honeycomb structure and geometry parameters isstudied.The relationship between the out-of-plane Young’s modulus and in-planeYoung’s modulus of at the same geometry parameters, and the trend of theout-of-plane transverse shear modulus with different geometry parameters areanalyzed. The possibility of tetrachiral honeycomb to achieve maximum in-planeYoung’s modulus with minimum density and maximum out-of-plane Young’smodulus with minimum in-plane Young’s modulus is studied. By tensile test forthe chiral honeycomb with three ligaments (Trichiral Honeycomb), the in-planemechanical properties are discussed; the qualitative analysis of the relationshipbetween the geometric parameters of the trichiral honeycomb structure isanalyzed and provides reference about trichiral honeycomb structure for the further research. The properties of Young’s modulus, transverse shear modulusand Poisson’s ratio of the chiral honeycomb structure with six ligaments(Hexachiral Honeycomb), tetrachiral honeycomb, trichiral honeycomb, and theirrelation to geometric parameters are compared. A chiral honeycomb structureenvelope bearing experiment is designed and the out-of-plane carrying capacityof various types of chiral honeycomb structure is discussed.The research of chiral honeycomb structure shows that chiral honeycombstructure can realize requirements of the low in-plane modulus and highout-of-plane stiffness, which can be used as wing skin structure of morphingaircrafts, or aerospace deployable structures. Chiral honeycomb is a novelcellular structure which can realize the multiple functions.