Integrated design of thermally actuated metastructure for modulatable dual vibration isolation function

Integrated metastructures capable of low-frequency vibration isolation while sustaining static load-bearing capacity have demonstrated outstanding performance in practical engineering applications. However, modulating their vibration isolation function for varying load-bearing conditions remains a challenge. To address this challenge, we propose a novel approach in which the metastructure encompasses thermally actuated unit cells. A theoretical model is first developed for metastructure’s unit cell with a bi-material double-layer curved beam, which enables the tuning of the effective stiffness characteristics via thermal actuation. The static characteristics of the unit cell are analyzed theoretically and validated numerically. By harnessing bi-material thermal expansion mismatch in the double-layer beam buckling, a significantly broadened stiffness tuning range is observed. A comprehensive parameter analysis and the corresponding design of the unit cell are performed. The metastructures are then investigated in two original modulatable vibration isolation scenarios: In Scenario 1, under varying loading masses, the initial vibration isolation frequency of the metastructure is managed to keep constant; In Scenario 2, under constant loading masses, the initial vibration isolation frequency of the metastructure is decreased so as to reach the vibration isolation region. Overall, the proposed thermally actuated design strategy offers an innovative approach for the creation of compact metastructures that are adaptable to complex working environments with a dual low-frequency vibration isolation function in case of both varying and constant load-bearing conditions.