Broadband Seismic Isolation of Periodic Ladder Frame Structure

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Rajan Prasad ◽  
Abhijit Sarkar
Keyword(s):  
Periodic Structure ◽  
Seismic Isolation ◽  
Periodic Structures ◽  
Stop Band ◽  
Design Guidelines ◽  
Unit Cell ◽  
Frame Structure ◽  
Design Parameters ◽  
Pictorial Presentation ◽  
Selection Of

Abstract Ladder frame structures are used as models for multistorey buildings. These periodic structures exhibit alternating propagating and attenuating frequency bands. Of the six different wave modes of propagation, two modes strongly attenuate at all frequencies. The other four modes have nonoverlapping stop band characteristics. Thus, it is challenging to isolate such structures when subjected to broadband, multimodal base excitation. In this study, we seek to synthesize a periodic ladder frame structure that has attenuation characteristics over the maximal range of frequencies for all the modes of wave propagation. We synthesize a unit cell of the periodic structure, which comprises two distinct regions having different inertial, stiffness, and geometric properties. The eigenvalues of the transfer matrix of the unit cell determines the attenuating or the nonattenuating characteristics of the structure. A novel pictorial presentation in the form of eigenvalue map is developed. This is used to synthesize the optimal unit cell. Also, design guidelines for suitable selection of the design parameters are presented. It is shown that a large finite periodic structure comprising a unit cell synthesized using the present approach has significantly better isolation characteristics in comparison to the homogeneous or any other arbitrarily chosen periodic structure.

Broadband Vibration Isolation for Rods and Beams Using Periodic Structure Theory

2018 ◽  
Vol 86 (2) ◽  
Author(s):  
Rajan Prasad ◽  
Abhijit Sarkar
Keyword(s):  
Periodic Structure ◽  
Vibration Isolation ◽  
Periodic Structures ◽  
Stop Band ◽  
Extreme Case ◽  
Unit Cell ◽  
Structure Theory ◽  
Seismic Excitations ◽  
Stiffness Properties ◽  
Selection Of

The alternating stop-band characteristics of periodic structures have been widely used for narrow band vibration control applications. The objective of this work is to extend this idea for broadband excitations. Toward this end, we seek to synthesize a longitudinal and a flexural periodic structure having the largest fraction of the frequencies falling in the attenuation bands of the structure. Such a periodic structure when subjected to broadband excitation has minimal transmission of the response away from the source of excitation. The unit cell of such a periodic structure is constituted of two distinct regions having different inertial and stiffness properties. We derive guidelines for suitable selection of inertial and stiffness properties of the two regions in the unit cell such that the maximal frequency region corresponds to attenuation bands of the periodic structure. It is found that maximal dissimilarity between the neighboring regions of the unit cell leads to maximal attenuating frequencies. In the extreme case, it is found that more than 98% of the frequencies are blocked. For seismic excitations, it is shown that large, finite periodic structures corresponding to the optimal unit cell derived using the infinite periodic structure theory has significant vibration isolation benefits in comparison to a homogeneous structure or an arbitrarily chosen periodic structure.

Invariant Representation of Wave Propagation Properties for a Mono-Coupled Electro-Mechanical Periodic Structure

2016 ◽  
Author(s):  
Edoardo Belloni ◽  
Francesco Braghin ◽  
Gabriele Cazzulani ◽  
Mattia Cenedese
Keyword(s):  
Wave Propagation ◽  
Periodic Structure ◽  
Seismic Isolation ◽  
Periodic Structures ◽  
Design Parameters ◽  
Invariant Representation ◽  
Electric Circuits ◽  
Peculiar Characteristic ◽  
Potential Applications ◽  
Propagation Properties

During the last decades, a growing interest has been devoted to periodic structures and metamaterials. One of the most interesting characteristics of this class of materials is that they present a transmission gap for given frequency ranges. This peculiar characteristic has many potential applications: from optics to seismic isolation, from filtering to wave guiding. In literature, different approaches were developed to study such kind of structures. In this paper, using an approach based on transfer matrices of a single unit cell and its invariants, a way to represent in compact form the behavior of a mono-coupled periodic structure is presented. As a result, the wave propagation properties are shown as being dependent both on the frequency range and on some chosen design parameters. Furthermore, the adding of multiphysics materials (in the case of this paper piezoelectric inserts with dedicated electric circuits) inside the structure allows, through the tuning of both the mechanical and the electrical parameters, to actively control the bandgap position. This approach also allows checking the robustness of parameter choices with respect to desired bandgap frequency ranges. Finally, some applications of this method for active control of wave propagation are presented.

(Generalized) Bloch mode synthesis for the fast dispersion curve calculation of 3D periodic metamaterials

2021 ◽  
Vol 263 (4) ◽  
pp. 2102-2113
Author(s):  
Vanessa Cool ◽  
Lucas Van Belle ◽  
Claus Claeys ◽  
Elke Deckers ◽  
Wim Desmet
Keyword(s):  
Dispersion Curve ◽  
Periodic Structures ◽  
Cell Model ◽  
Stop Band ◽  
Computational Cost ◽  
Order Reduction ◽  
Element Model ◽  
Unit Cell ◽  
Reduction Techniques ◽  
Bloch Mode

Metamaterials, i.e. artificial structures with unconventional properties, have shown to be highly potential lightweight and compact solutions for the attenuation of noise and vibrations in targeted frequency ranges, called stop bands. In order to analyze the performance of these metamaterials, their stop band behavior is typically predicted by means of dispersion curves, which describe the wave propagation in the corresponding infinite periodic structure. The input for these calculations is usually a finite element model of the corresponding unit cell. Most common in literature are 2D plane metamaterials, which often consist of a plate host structure with periodically added masses or resonators. In recent literature, however, full 3D metamaterials are encountered which are periodic in all three directions and which enable complete, omnidirectional stop bands. Although these 3D metamaterials have favorable vibro-acoustic characteristics, the computational cost to analyze them quickly increases with unit cell model size. Model order reduction techniques are important enablers to overcome this problem. In this work, the Bloch Mode Synthesis (BMS) and generalized BMS (GBMS) reduction techniques are extended from 2D to 3D periodic structures. Through several verifications, it is demonstrated that dispersion curve calculation times can be strongly reduced, while accurate stop band predictions are maintained.

Analysis of Effect on Seismic Response of Base Isolated Building with Openings Floor for the Elastic Stiffness of Isolation Layer

2014 ◽  
Vol 933 ◽  
pp. 316-319
Author(s):  
Ming Mei Jiang
Keyword(s):  
Seismic Response ◽  
Seismic Isolation ◽  
Elastic Stiffness ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Isolation Layer ◽  
Reinforced Concrete Frame Structure ◽  
The Relationship ◽  
Selection Of

Currently the studies on the effects of seismic isolation layer parameters on seismic response of base isolated structure are so few. So this paper used the software ANSYS to analyze seismic response of a reinforced concrete frame structure with openings slab. It focused on the relationship between the isolation layer of the elastic stiffness and isolation effect, and provided reference for reasonable selection of seismic isolation layer parameters.

The Effect of Isolation Layer Yield Stress on the Seismic Response of Base Isolated Frame Structure

2013 ◽  
Vol 339 ◽  
pp. 635-637
Author(s):  
Fang Zhang
Keyword(s):  
Yield Stress ◽  
Seismic Isolation ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Isolation Layer ◽  
Reinforced Concrete Frame Structure ◽  
Isolation Effects ◽  
The Relationship ◽  
Selection Of

At present the research on the effect of the isolation layer parameters on earthquake response of base-isolated structure is rarely. To solve this problem, this paper taking a reinforced concrete frame structure for example, used ANSYS software to analyze the response of base-isolated structure under earthquake. It focused on the relationship between the isolation layer yield stress and the isolation effects, and provided reference for reasonable selection of seismic isolation layer parameters.

Metastructure With Piezoelectric Element for Simultaneous Vibration Suppression and Energy Harvesting

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Guobiao Hu ◽  
Lihua Tang ◽  
Arnab Banerjee ◽  
Raj Das
Keyword(s):  
Mathematical Model ◽  
Energy Harvesting ◽  
Band Gap ◽  
Electromechanical Coupling ◽  
Vibration Suppression ◽  
Stop Band ◽  
Design Guidelines ◽  
Unit Cell ◽  
Coupled Systems ◽  
Piezoelectric Energy

Inspired by the mechanism of acoustic–elastic metamaterial (AEMM) that exhibits a stop band gap for wave transmission, simultaneous vibration suppression and energy harvesting can be achieved by integrating AEMM with energy-harvesting component. This article presents an analytical study of a multifunctional system based on this concept. First, a mathematical model of a unit-cell AEMM embedded with a piezoelectric transducer is developed and analyzed. The most important finding is the double-valley phenomenon that can intensively widen the band gap under strong electromechanical coupling condition. Based on the mathematical model, a dimensionless parametric study is conducted to investigate how to tune the system to enhance its vibration suppression ability. Subsequently, a multicell system is conceptualized from the findings of the unit-cell system. In a similar way, dimensionless parametric studies are conducted to optimize the vibration suppression performance and the energy-harvesting performance severally. It turns out that different impedance matching schemes are required to achieve optimal vibration suppression and energy harvesting. To handle this problem, compromising solutions are proposed for weakly and strongly coupled systems, respectively. Finally, the characteristics of the AEMM-based piezoelectric energy harvester (PEH) from two functional aspects are summarized, providing several design guidelines in terms of system parameter tuning. It is concluded that certain tradeoff is required in the process of optimizing the performance toward dual functionalities.

Analysis of the Influence on the Dynamic Characteristics of Base Isolated Frame Structure for the Elastic Stiffness of the Isolation Layer

2013 ◽  
Vol 739 ◽  
pp. 272-274
Author(s):  
Fang Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Seismic Isolation ◽  
Elastic Stiffness ◽  
Frame Structure ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Isolation Layer ◽  
Reinforced Concrete Frame Structure ◽  
Isolation Effects ◽  
Selection Of

In the design of base isolated structure, the parameter of seismic isolation layer is very important. At this problem, taking the reinforced concrete frame structure for example, using ANSYS software, the paper analyzed the dynamic characteristics of the base isolated structure, focused on the relation of the elastic stiffness of isolation layer and the isolation effects, and provided reference for reasonable selection of seismic isolation layer parameter.

scholarly journals Phase-resonance Exploitation in Full-Metal 3D Periodic Structures for Single- and Multi- Wideband Applications

2021 ◽  
Author(s):  
Carlos Molero Jiménez
Keyword(s):  
Periodic Structure ◽  
Periodic Structures ◽  
Circuit Model ◽  
Unit Cell ◽  
Equivalent Circuits ◽  
Cell Architecture ◽  
Complex Unit Cell ◽  
Phase Resonance

This paper presents a versatile full-metal 3D periodic structure based on square waveguides with non-closed resonators perforated on their walls. The complex unit-cell architecture is modelled via accurate equivalent circuits, previously characterized. The circuit model predicts the excitation of phase resonance, which will be used to optimize and design different functionalities, such as polarisation converters or absorption.

scholarly journals Phase-resonance Exploitation in Full-Metal 3D Periodic Structures for Single- and Multi- Wideband Applications

2021 ◽  
Author(s):  
Carlos Molero Jiménez
Keyword(s):  
Periodic Structure ◽  
Periodic Structures ◽  
Circuit Model ◽  
Unit Cell ◽  
Equivalent Circuits ◽  
Cell Architecture ◽  
Complex Unit Cell ◽  
Phase Resonance

This paper presents a versatile full-metal 3D periodic structure based on square waveguides with non-closed resonators perforated on their walls. The complex unit-cell architecture is modelled via accurate equivalent circuits, previously characterized. The circuit model predicts the excitation of phase resonance, which will be used to optimize and design different functionalities, such as polarisation converters or absorption.

The Effect of Yield Strength in Isolation Layer on Dynamic Characteristics of Floor Partial Discontinuous Isolation Building

2014 ◽  
Vol 933 ◽  
pp. 320-322
Author(s):  
Peng Zhang
Keyword(s):  
Dynamic Characteristics ◽  
Seismic Isolation ◽  
Frame Structure ◽  
Ansys Software ◽  
Reinforced Concrete Frame ◽  
Concrete Frame ◽  
Isolation Layer ◽  
Reinforced Concrete Frame Structure ◽  
The Relationship ◽  
Selection Of

In the design of base isolated structure, the design of seismic isolation layer parameters is very important. Aiming at this problem, this paper using reinforced concrete frame structure of a partial discontinuity floor as an example, using ANSYS software, analyzed the dynamic characteristics of the based isolated structure, focused on the relationship between the yield stress of the isolation layer and the isolation effect, to provide reference for reasonable selection of seismic isolation layer parameters.

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