Quasi-zero-stiffness metamaterial pipe for low-frequency wave attenuation

Cai, Changqi; Zhou, Jiaxi; Wang, Kai; Lin, Qida; Xu, Daolin; Wen, Guilin

doi:10.1016/j.engstruct.2022.115580

Cited by 21 publications

(4 citation statements)

References 80 publications

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“…In order to obtain the energy attenuation formula (transmittance formula) of laser passing through attenuator, Jones matrix can be used to calculate it [7][8] . Assuming that the optical axes of the polarizing beamsplitting cube and the zero-order vortex half-wave retarder correspond to the x-axis of the coordinate system and coincide completely, there is an angle θ between the vibration direction S1 of the incident light and the optical axis, and the transmission direction U of the polarizing beamsplitting cube is the same as the vibration direction of the incident light beam.…”

Section: Attenuator Principlementioning

confidence: 99%

A method and device for continually adjusted attenuation of high energy laser

Wu,

Ni,

et al. 2024

Speckle 2023: VIII International Conference on Speckle Metrology

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The laser attenuation device has always been an important component of the LIDT system,the attenuation adjustment ability of the laser attenuation device directly affects the performance of the testing system.The continuous attenuation device of high energy laser is achieved by combining polarization cube with rotating half wave plate,when the angle of the rotating half wave plate changes from 0°to 45°, the transmissivity of the attenuator changes from 99.9% to 0.3%.This design scheme reduces the volume of the attenuation device while achieving continuous adjustment of the transmissivity.Adopting optical devices with large aperture and high damage threshold, the maximum single pulse energy that the system can withstand is 2J@1064nm. The attenuated energy is tested by using a Ophir PE50BF-DIF-C pyroelectric energy sensor,the results show that the laser energy transmissivity can be continuously adjusted within the range of [0.3%,99.9%]. Using Beamtech China SGR20 laser, it can work stably with the power density of 2J@1064nm whose experimental results meet the design re-quirements. Compared with the traditional optical variable attenuator,this design has the advantages of large dynamic regulation range, stable attenuation and continuous regulation.

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Section: Attenuator Principlementioning

confidence: 99%

A method and device for continually adjusted attenuation of high energy laser

Wu,

Ni,

et al. 2024

Speckle 2023: VIII International Conference on Speckle Metrology

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“…[21][22][23] In addition, the excitation is positioned at a distance of 10a from the SM to ensure that only the surface wave interacts with the SM, as the surface wave exhibits maximum energy at the soil surface and rapidly diminishes away from it. 12,23 Moreover, to minimize the impact of unnecessary wave reflection, perfectly matched layers (PMLs) with a thickness of 3a are deployed at the bottom and four sides of the model. The transmission obtained from FDA is utilized to characterize the wave attenuation performance, which can be calculated as follows:…”

Section: Embedded Unit Cell Design and Evaluationmentioning

confidence: 99%

“…Previous studies have demonstrated that the seismic ground motion can be reduced by over 90% if the SM dimension along the direction of wave propagation is similar to the seismic wavelength. 12 8 unit cells are positioned along the wave propagation direction in this study, resulting in a total dimension of 20 m (i.e., 8a), considerably smaller than the seismic wavelength. As a result, relatively weak wave attenuation is observed within this specific frequency range.…”

Section: Embedded Unit Cell Design and Evaluationmentioning

confidence: 99%

Enhanced seismic wave attenuation in graded seismic metamaterials with novel unit cells

Pan,

Wang,

Zhou

2024

Active and Passive Smart Structures and Integrated Systems XVIII

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In recent years, seismic metamaterials (SMs) have attracted considerable attention for their capacity to manipulate seismic wave propagation. Unlike conventional seismic mitigation methods, SMs offer broader applicability and enhanced seismic energy absorption capabilities. Despite the burgeoning interest in SM research, the focus has predominantly been on the design of SM unit cells. The introduction of SM layout pattern design, a novel strategy to achieve superior wave shielding performance, has proven effective in enhancing the seismic protection of infrastructures. However, existing research on SM pattern design primarily centers on graded SMs with linear layouts, neglecting the exploration of more intricate layout patterns. To bridge this research gap, this study proposes a hierarchical design strategy that integrates a novel embedded SM unit cell design with the exploration of three graded SM layout patterns including one linear and two polynomial patterns. Subsequently, the frequency domain analysis (FDA) method is developed to assess the wave attenuation performances of the proposed SMs. The analysis results demonstrate that compared to the non-graded SM, the proposed graded SMs exhibit elevated seismic wave attenuation capabilities, suggesting potentials for advanced wave reduction.

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“…Scholars interested in constant-force mechanisms can refer to the literature [25,26,29]. At present, there are two main methods for designing QZS [30]: one is to provide a QZS region for nonlinear stiffness by optimizing the geometric shape of the elastic element [31]; another is to meet the QZS characteristics by connecting negative stiffness and positive stiffness in parallel [32]. This design method has higher flexibility, and the structural parameters of the QZS isolator can be flexibly adjusted according to actual application conditions.…”

Section: Introductionmentioning

confidence: 99%

Quasi-Zero Stiffness Isolator Suitable for Low-Frequency Vibration

et al. 2023

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This paper proposes a quasi-zero stiffness (QZS) isolator based on an inclined trapezoidal beam to explore its advantages in low-frequency passive vibration isolation. The nonlinear stiffness of the inclined trapezoidal beam due to the buckling effect is investigated through finite element simulation, and a linear positive stiffness spring is connected in parallel to form a QZS isolator with high-static and low-dynamic stiffness performance. The natural frequency of the isolator in the QZS region is simulated and analyzed, and the dynamic response of the QZS isolator under different damping ratios, excitation and load conditions is explored. The prototype of the QZS isolator was manufactured, and a static compression experiment was conducted to obtain its nonlinear stiffness. The dynamic experiment results verify the correctness of the simulation conclusions. The simulation and experimental data demonstrate that the QZS isolator has the characteristics of lower initial isolation frequency compared with the equivalent linear isolator. The proposed QZS isolator has an initial isolation frequency of 2.91 Hz and achieves a 90% isolation efficiency at 7.02 Hz. The proposed QZS isolator has great application prospects and can provide a reference for optimizing low-frequency or ultra-low-frequency isolators.

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Quasi-zero-stiffness metamaterial pipe for low-frequency wave attenuation

Cited by 21 publications

References 80 publications

A method and device for continually adjusted attenuation of high energy laser

A method and device for continually adjusted attenuation of high energy laser

Enhanced seismic wave attenuation in graded seismic metamaterials with novel unit cells

Quasi-Zero Stiffness Isolator Suitable for Low-Frequency Vibration

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