On June 20, 2023, the “Seminar on Acoustics and Fluctuating Metamaterials” was held at Motion Structures Laboratory (MSL), Tianjin University. Prof. Rui Zhu from Beijing University of Technology, Prof. Hongli Ji from Nanjing University of Aeronautics and Astronautics, Prof. Zuojia Wang from Zhejiang University, Assoc. Prof. Xiujuan Zhang from Nanjing University and Prof. Yanfeng Wang from Tianjin University were invited to discuss the topic of acoustics and fluctuating metamaterials. The above experts and Prof. Jiayao Ma from MSL gave wonderful academic presentations to the teachers and students.

        Firstly, Prof. Yan Chen showed the experts around the laboratory and introduced the research work of the team in detail. Then, Prof. Rui Zhu gave a fascinating presentation on “Mechanism-based broadband metamaterials design and fluctuation/vibration control”. First, Prof. Rui Zhu presented a series of mechanical metamaterials with broad and low frequency wave control capability, realising ultra broadband wave-filtering, wave-splitting, and mode-conversing. Second, using modular origami construction and reconfiguration method, metamaterials with specific number of zero modes and the capability to be transformed among all seven different zero modes are realised. In addition, Prof. Rui Zhu also presented research results on broad and low frequency aerospace micro-vibration control, which has significantly improved the vibration isolation capability of spacecraft structures.

        Prof. Hongli Ji gave a fascinating presentation on “Acoustic black hole structures and their applications in aerospace”. Starting from the basic principles of acoustic black holes, Prof. Ji explained the research background, difficulties, modeling methods, and structural design optimization methods of acoustic black holes, and demonstrated the typical applications of acoustic black holes in aircraft vibration suppression.

        Prof. Zuojia Wang gave a fascinating presentation on “Progress in the Research of Origami Electromagnetic Materials”. Prof. Wang’s presentation introduced the development and latest research progress of artificial electromagnetic materials, discussed the mechanisms of dielectric anisotropy, chirality, and non-local effects in structural deformation, and demonstrated the latest research progress of origami electromagnetic structures in polarisation regulation, radiation control, and circuit design.

        Assoc. Prof. Xiujuan Zhang gave a fascinating presentation on “Research on topological physics in artificial microstructured materials”. Prof. Zhang first introduced the concept and principle of topological materials and then introduced the mechanism of realization of higher-order topological phases, new effects of higher-order topologies, such as multi-dimensional topological phase transition, quadrupolarization, dipolarization, and other methods of realizing higher-order topological phases, as well as new effects of topology such as position-selectable higher-order topological states.

        Prof. Yanfeng Wang gave a fascinating presentation on “Exploring the design and application of acousto-vibration coupling super-surfaces”. Prof. Wang first explained the basic design concepts and theories of Acoustic superstructure materials and then introduced the research results on underwater acoustic super-surfaces and trans-water-air acoustic super-surfaces, the relevant research solved important challenges in water-air communication engineering.

        Prof. Jiayao Ma gave a fascinating presentation on “Design and Analysis of Reconfigurable Origami Metamaterials”. Prof. Ma introduced the double corrugated origami metamaterial based on the reconfiguration of the peak and valley crease arrangement and a reconfigurable modular origami metamaterial with adjustable Poisson’s ratio and symmetry and gave a fascinating and detailed explanation of their design methods.

        The seminar enhanced academic exchanges within the field of metamaterials, deepened students’ understanding of research related to fluctuating metamaterials including acoustics and electromagnetism, and provided broader ideas for solving multidisciplinary crossover problems.