Lattice Based Elastic Metamaterials with Ultra-wide Stopbands at Low Frequency
Lattice-based elastic metamaterials (EMMs) with periodically engineered cells exhibit unprecedented properties. One exotic attribute of EMMs is the bandgap, in which elastic waves， within specific frequency ranges are prohibited from transmitting. While putting EMMs into use in real-life applications, nonetheless, their applicability remains limited due to the deficiency in the well-established design methods for EMMs, especially three-dimensional (3D) EMMs (including both infinite and finite EMMs) to achieve low frequency and ultra-wide stopbands. Moreover, the inevitable system uncertainties stemming from heterogeneous sources in practical EMMs can lead to significant fluctuations in structural performance, and worse still, catastrophic structural failure may occur. Consequently, to facilitate the wide and safe application of these advanced materials, it is requisite to develop a comprehensive framework to analyze and design 3D EMMs with ultra-wide wave attenuation bands at low frequencies and implement reliability analysis for them. In this research, a systematic framework is developed for 3D latticed EMMs in order to improve their applicability across multiple engineering disciplines. Within the framework, the key components are the novel modal-based approaches, proposed for elaborating wave attenuation mechanisms, guiding the structural modifications, and manipulating geometrical parameters of 3D EMMs aiming at achieving low-frequency and ultra-wide stopbands. Besides, another core in the framework is the new virtual model-aided approach, which is introduced for estimating statistical information, including means, standard deviations, probability density functions (PDFs), and cumulative distribution functions (CDFs), and failure probabilities of the random bandgap characteristics for 3D EMMs involving material and geometrical uncertainties. Based on the numerical investigations, the wave attenuation mechanisms in latticed 3D EMMs are elaborated. Moreover, the effectiveness of the developed modal-based approaches to design 3D EMMs and the computational performance, such as robustness, efficiency, and accuracy of the virtual model-aided framework are demonstrated. Convincedly, the developed framework facilitates the wide and safe applications of EMMs, significantly benefiting their applicability in real-life scenarios across diverse fields.
Elastic Metamaterials, Bandgap Optimization, Machine Learning, anzsrc-for: 401702 Dynamics, vibration and vibration control, anzsrc-for: 400510 Structural engineering, anzsrc-for: 401706 Numerical modelling and mechanical characterisation
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