Tunable three-dimensional nonreciprocal transmission in a layered nonlinear elastic wave metamaterial by initial stresses

Li, Zhenni; Wang, Yi–Ze; Wang, Yue-Sheng

doi:10.1007/s10483-021-2808-9

Cited by 6 publications

(1 citation statement)

References 45 publications

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“…Taking the foundation piles of high-rise buildings as the detection object, the foundation piles of general buildings are completed with concrete pouring. In the sound velocity evaluation, for the foundation piles with good quality, the fluctuation state of the sound velocity is consistent with the fluctuation of the concrete quality, and both obey the normal distribution [16]. In practice, the method often used to analyze the speed of sound is the probabilistic method.…”

Section: Acoustic Detection Methodmentioning

confidence: 98%

Detection and Function of Elastic Wave Tomography of Foundation Piles of High-Rise Buildings under the Background of Internet of Things

Guo

Liu

2022

Wireless Communications and Mobile Computing

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Foundation piles are a widely used foundation form for high-rise buildings. Its main function is to reduce the settlement of buildings. In recent years, in areas with good upper soil conditions, in order to reduce the amount of earthwork excavation and transportation, more and more engineering buildings use foundation piles. Therefore, the status of foundation piles in construction projects is becoming more and more important. The high-rise building foundation pile project belongs to the underground concealed project. In the construction process, it is greatly affected by factors such as construction technology and geology. After the construction is completed, it is difficult to observe the changes inside the foundation pile with the naked eye as time goes by. A series of problems such as building collapse, settlement, and cracking often occur, thus affecting normal use and causing some safety accidents. In order to solve these series of problems, this paper proposes an elastic wave tomography detection method. It performs imaging inversion calculation on the inside of the foundation pile, and many methods are used in it. In the canonical Gaussian-damped Newton method in tomography, its iteration rate is 3.5% higher than that of the canonical Gaussian-Newton method, the convergence speed is accelerated, the accuracy is high, and the error is small. In the process of detection, this method is more suitable to detect the integrity and quality of foundation piles.

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Section: Acoustic Detection Methodmentioning

confidence: 98%

Detection and Function of Elastic Wave Tomography of Foundation Piles of High-Rise Buildings under the Background of Internet of Things

Guo

Liu

2022

Wireless Communications and Mobile Computing

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Size effects on the mixed modes and defect modes for a nano-scale phononic crystal slab

Jin

2022

Appl. Math. Mech.-Engl. Ed.

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The size-dependent band structure of an Si phononic crystal (PnC) slab with an air hole is studied by utilizing the non-classic wave equations of the nonlocal strain gradient theory (NSGT). The three-dimensional (3D) non-classic wave equations for the anisotropic material are derived according to the differential form of the NSGT. Based on the the general form of partial differential equation modules in COMSOL, a method is proposed to solve the non-classic wave equations. The bands of the in-plane modes and mixed modes are identified. The in-plane size effect and thickness effect on the band structure of the PnC slab are compared. It is found that the thickness effect only acts on the mixed modes. The relative width of the band gap is widened by the thickness effect. The effects of the geometric parameters on the thickness effect of the mixed modes are further studied, and a defect is introduced to the PnC supercell to reveal the influence of the size effects with stiffness-softening and stiffness-hardening on the defect modes. This study paves the way for studying and designing PnC slabs at nano-scale.

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Reconfigurable metamaterial for asymmetric and symmetric elastic wave absorption based on exceptional point in resonant bandgap

Xia

et al. 2022

Appl. Math. Mech.-Engl. Ed.

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Elastic wave absorption at subwavelength scale is of significance in many engineering applications. Non-Hermitian metamaterials show the ability in high-efficiency wave absorption. However, the single functionality of metamaterials is an important limitation on their practical applications for lack of tunability and reconfigurability. Here, we propose a tunable and reconfigurable non-Hermitian piezoelectric metamaterial bar, in which piezoelectric bars connect with resonant circuits, to achieve asymmetric unidirectional perfect absorption (UPA) and symmetric bidirectional perfect absorption (PA) at low frequencies. The two functions can be arbitrarily switched by rearranging shunted circuits. Based on the reverberation-ray matrix (RRM) method, an approach is provided to achieve UPA by setting an exceptional point (EP) in the coupled resonant bandgap. By using the transfer matrix method (TMM) and the finite element method (FEM), it is observed that a non-Hermitian pseudo-band forms between two resonant bandgaps, and the EP appears at the bottom of the pseudo-band. In addition, the genetic algorithm is used to accurately and efficiently design the shunted circuits for desired low-frequency UPA and PA. The present work may provide new strategies for vibration suppression and guided waves manipulation in wide potential applications.

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Tunable three-dimensional nonreciprocal transmission in a layered nonlinear elastic wave metamaterial by initial stresses

Cited by 6 publications

References 45 publications

Detection and Function of Elastic Wave Tomography of Foundation Piles of High-Rise Buildings under the Background of Internet of Things

Detection and Function of Elastic Wave Tomography of Foundation Piles of High-Rise Buildings under the Background of Internet of Things

Size effects on the mixed modes and defect modes for a nano-scale phononic crystal slab

Reconfigurable metamaterial for asymmetric and symmetric elastic wave absorption based on exceptional point in resonant bandgap

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