Buckling enhancement of tubular metamaterial with axial zero thermal expansion by integrating two adjustment mechanisms

Artificially designed mechanical metamaterials with desired property of zero thermal expansion (ZTE) have already made great progress motived by the urgent needs of high-end equipment and instruments served in large fluctuating temperature environment. Various thermal expansion adjustment mechanisms are developed to achieve controllable thermal deformation. However, only designing ZTE is not normally sufficient, but must be combined with enough mechanical performances for carrying mechanical loads. Hence in this study, a method of bucking enhancement for designing tubular metamaterials with axial ZTE is firstly proposed by integrating two existing adjustment mechanisms. Compared with the previous design under the single Poisson contraction mechanism, the present axial ZTE property is mainly achieved through thermally bending-adjustment mechanism, and therefore avoid the unfeasibility of requiring too large thermal expansion coefficient difference for constituent materials. Meanwhile, the significant buckling capacity loss caused by the introduced initial curvature used for triggering thermally bending-adjustment mechanism is prominently improved by taking the advantage of Poisson contraction mechanism. The results obtained from detailed numerical simulations verify the design targets of simultaneous axial ZTE and buckling enhancement. The proposed design strategy of mechanism combination is also proved effective to enhance the buckling capacity of present dual-mechanism metamaterial without obvious increase of structural mass.