Load-bearing sandwiched metastructure with zero thermal-induced warping and high resonant frequency: Mechanical designs, theoretical predictions, and experimental demonstrations

Current designs of the metastructure can hardly satisfy the demands of the continuous advancement of space exploration. Thus, a new design strategy for the sandwiched metastructure with zero thermal-induced warping, high load-bearing capability, and high resonant frequency is urgently needed and provided here. The metastructure composed of three layers: the top plate and the lattice filled sandwiched layer in material I, and the bottom plate in material II. Theoretical models are derived via the flexibility method and fixed-point deformation assumption, revealing the dependences of out-of-plane thermal-induced warping, mechanical-thermal stability, and load-bearing capability on the dominated geometrical parameters of the metastructure. The remarkable agreements among theoretical predictions, FEA results, and experimental measurements provide the accuracy of the theoretical model in predicting structural thermal-induced warping. Compared with the bi-material structure without the interlayer, the sandwiched metastructure exhibits a negligible out-of-plane thermal-induced warping, reduced by 99.8% (i.e., 0.042μm/°C). Additionally, high load-bearing capability (i.e., 0.17GPa) and high resonant frequency (i.e., 532.3Hz) of the metastructure are validated by FEAs and experiments. In summary, this metastructure design can significantly improve the thermal-mechanical stability of functional components of the spacecraft.