Multi-Polarization Vibration Modes and Bandgap Regulation Mechanism of the Multi-Bandgap Lightweight Plate-Truss Hybrid Structures

To address the challenge of multi-frequency and multi-mode vibration in structural systems—such as bending and torsional modes—this study proposes plate-truss hybrid structures capable of generating multiple elastic wave bandgaps with various polarization modes. Unlike traditional elastic metamaterials that typically target a single frequency band or wave mode, the proposed design enables multi-band and multi-mode vibration suppression. Finite element simulations based on Bloch’s theorem are used to systematically investigate the bandgap characteristics. The results reveal that the structures exhibit different bandgaps, enabling wideband elastic wave attenuation. Parametric studies further show that tuning geometric features, such as rod radii and wall thickness, can effectively shift bandgap positions to lower frequencies and expand their bandwidth. Prototypes of the plate-truss hybrid structures are fabricated using selective laser melting technology, and their vibration attenuation performance is validated through frequency sweep tests. The experimental results show good agreement with numerical predictions, confirming the effectiveness of the design. This work elucidates the mechanisms of multi-bandgap formation and tunability, offering a promising strategy for advanced vibration mitigation in aerospace and related applications.