A new design concept of dual-constituent sandwich panel with in-plane zero thermal expansion

Abstract

The lattice metamaterials with zero, large positive or negative coefficients of thermal expansions (CTEs) have attracted much attention because of urgent demands in practical engineering structure. Due to the porosity of the above lattice metamaterials, most of structures made of them are also porous and are unsuitable to the outermost need to seal, for example, the skin of supersonic vehicles. In this paper, a new design concept of dual-constituent sandwich panel with in-plane zero thermal expansion is proposed. Different from the structures made of porous metamaterial with zero CTE, the upper and lower face-sheets of sandwich panels are all solid and not porous. The counterintuitive properties come from the special design of face-sheets, which are comprised of bi-layer materials with different positive CTEs. The difference of CTEs of two bonded layers leads to transverse bending of face-sheet during temperature increase, which results in the in-plane contraction and thereby compensates the in-plane thermal expansion deformation. The core is connected to the special locations on face-sheets to ensure the desired thermal transverse deformation occurs. In order to verify the validity of the design concept, two kinds of specific examples of corrugated and lattice sandwich panels are separately presented. The results indicate they can separately achieve in-plane unidirectional and bidirectional zero thermal expansion if the appropriate structure parameters and materials are selected.