Multi-functional metamaterial based on overdamping effect: Design, investigation, optimization

As metamaterials are widely used in engineering fields, the demand for the extraordinary properties of metamaterials is no longer satisfied with a single function. The multi-functional integrated design of metamaterial structure is the basis of a new research direction and technology path applied to engineering equipment with complex working conditions. At present, in the aerospace, transportation, and other engineering fields, there is a high demand for lightweight mechanical metamaterials with high mechanical properties and strong energy absorption characteristics. Therefore, an integrated design method of multi-functional metamaterial structures with impact resistance and vibration reduction characteristics is proposed in the work. Through the stiffness analysis of the curved beam structure, the influence law of the structure parameters on stiffness is obtained, to design the structure form which is prone to rotating buckling and realize the limitation of impact energy. In addition, by tuning the strain of the cell structure, the characteristic frequency is reduced to zero, to obtain the overdamping effect and greatly improve the impact energy attenuation characteristics of the structure. The multi-layer design idea is integrated into the structural design, and the combination of hyperelastic material and metal is adopted to realize the integrated design of high stiffness and high damping characteristics, and the design criteria of lightweight is guaranteed. Based on the design concept of biomimetic metamaterials, the multi-scale lattice structure with local resonant bandgap is constructed through fractal design. By introducing the improved IHB method, the bandgap characteristics of the lattice structure are analyzed theoretically, and the vibration control technology with the large bandwidth is realized by parameter design, in which the bandwidth range is up to 5kHz. Through the design strategy of the multi-stage energy absorption structure, the energy dissipation characteristics of the structure are further improved, the limit of structure thickness is broken, and the excellent energy absorption effect is achieved under the condition of low-thickness (single-layer array structure), in which the attenuation rate of impact displacement and impact acceleration is greater than 97 %. The key problem that dynamic mechanical properties are difficult to integrate with static mechanical properties in metamaterial structures is solved. The vibration control characteristics and impact resistance characteristics of the structure are verified by experiments, which confirms the authenticity and accuracy of the research work. The work achieves perfect compatibility of impact resistance characteristics and vibration reduction characteristics and achieves an excellent energy absorption effect with the single-layer array structure. It provides the theoretical and technical basis for the development of multi-functional integrated design methods of metamaterial structures and provides technical support for the application of metamaterial structures in engineering problems.