A Simplified Modeling Framework of Higher‐Order Topological States in Elastic Metaplates

Higher‐order topological insulators (HOTIs) extend beyond conventional topological materials by supporting higher‐dimensional topological corner/hinge states, offering unprecedented opportunities for wave control in elastic systems. While phononic crystals composed of thin plates loaded by prisms/pillars have demonstrated HOTI phenomena, the intricate polarization properties of elastic waves complicate theoretical modeling and predictive design. Herein, a simplified elastic metaplate composed of periodically arranged plate‐pillar clusters (PPCs), achieving higher‐order corner states through the integration of dual PPCs with inverted topological phase properties, is proposed. Furthermore, a theoretical framework for PPC metaplates using a “mass‐spring” model in conjunction with multiple scattering theory is developed. The feasibility of the theoretical results is validated through simulations and experiments, successfully enabling theoretical modeling of higher‐order topological corner states in elastic wave systems. The design strategy and findings presented in this article provide important design references for the development of high‐dimensional, robust topological waveguides and devices in elastic wave systems.