Novel Design Scheme for Structural Fundamental Frequency of Porous Acoustic Metamaterials.

Structural resonance increases the vibration and noise of porous acoustic metamaterials while reducing the energy consumption and conversion efficiency of acoustic waves. Therefore, structural fundamental frequency of porous acoustic metamaterials is required to be controlled to avoid resonance. This study proposes a full-cycle interactive progressive (FIP) design scheme for porous acoustic metamaterials. The FIP design scheme first establishes a specific parameter relationship for the initial model based on the intentions of the designers. The initial model is then dynamically adjusted through a series of optimization processes. In particular, the FIP design scheme is developed for a porous acoustic metamaterial in an acoustic-structure interaction system. The effects of the structural parameters and applied boundary conditions of the porous acoustic metamaterial on the structural fundamental frequency are investigated. A surrogate model is introduced to reduce the calculation costs and improve the design efficiency of the parametric optimization. The frequency-modulation acoustic metamaterial is tailored to improve its acoustic and vibrational characteristics, including the resonance resistance and low dynamic response. The features of the FIP design scheme in the optimized design of porous acoustic metamaterials are demonstrated.

A Novel Design Method for Energy Absorption Property of Chiral Mechanical Metamaterials.

In this paper, a full-cycle interactive progressive (FIP) method that integrates topology optimization, parametric optimization, and experimental analysis to determine the optimal energy absorption properties in the design of chiral mechanical metamaterials is proposed. The FIP method has improved ability and efficiency compared with traditional design methods due to strengthening the overall design, introducing surrogate models, and its consideration of the application conditions. Here, the FIP design was applied in the design of mechanical metamaterials with optimized energy absorption properties, and a chiral mechanical metamaterial with good energy absorption and impact resistance was obtained based on the rotation mechanism of metamaterials with a negative Poisson's ratio. The relationship among the size parameters, applied boundary conditions, and energy absorption properties were studied. An impact compression experiment using a self-made Fiber Bragg Grating sensor was carried out on the chiral mechanical metamaterial. In light of the large deviation of the experimental and simulation data, a feedback adjustment was carried out by adjusting the structural parameters to further improve the mechanical properties of the chiral mechanical metamaterial. Finally, human-computer interaction, self-innovation, and a breakthrough in the design limits of the optimized model were achieved. The results illustrate the effectiveness of the FIP design method in improving the energy absorption properties in the design of chiral mechanical metamaterials.