The cylindrical mechanical metamaterial with high-level thermal-mechanical stabilities and high dynamic stiffness

Mechanical metamaterials with high-level thermal-mechanical stabilities are attracting increasing interest in aerospace. Although numerous configuration designs have been proposed, few of them can satisfy the demands of space explorations, mainly considering the inevitable geometric errors during the assembling process of the metamaterial using a number of parts. To address this issue, the design strategy of cylindrical mechanical metamaterials based on the building block assembly method is proposed here to achieve high-level thermal-mechanical stabilities and high dynamic stiffness. The mechanical and thermal properties of the metamaterial have been systematically studied in terms of theoretical predictions, Finite Element Analysis (i.e., FEA), and experimental measurements. The theoretical model proposed here has accurately predicted the thermal-mechanical behaviors of the metamaterial and demonstrated the capabilities of the metamaterial in achieving combined attributes of the good loading capability (i.e., 2.30 × 10⁶ kN mm/kg for the specific compression modulus, 1.02 × 10⁶ kN mm/kg for the specific shear modulus), the experimentally high thermal-mechanical stabilities (i.e., 0.037 ppm/°C), the high-level dynamic stiffness (i.e., 1013.84 Hz). Notably, the selective electron beam melting and the unique assemble method realize the feasibility of structurally integrated preparation of the metamaterial and achieve the reusability capability even once fabricated.