Design of Zig-Zag 1–3 Viscoelastic Composite Layer for the Improved Passive Damping Treatment of Beam

In this work, the damping characteristics of an actively constrained viscoelastic material layer are examined because of the inclusion of dispersed graphite particles within the viscoelastic material layer. The study is carried out by analysing the active–passive damping in a layered plate made of a substrate layer, a constrained viscoelastic particulate composite layer and a thin constraining piezoelectric actuator layer. The effective properties of the viscoelastic particulate composite are estimated using a differential scheme and the elastic–viscoelastic correspondence principle. The piezoelectric layer is activated according to the velocity feedback control law, and a closed-loop finite element model of the overall plate is derived for the analysis. The results reveal that the inclusion of graphite particles not only causes an improved transfer of active action from the piezoelectric layer to the substrate plate but also enhances the energy dissipation capability of the constrained viscoelastic layer. It is found that the maximum transfer of active action and the maximum passive damping capability of the viscoelastic particulate composite layer arise almost at the same volume fraction of inclusion. So, an optimal volume fraction of inclusion is obtained for significantly improved active–passive damping in the overall plate. The overall study presents a potential means of improved active–passive damping treatment of structural vibration.

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Optimal Damping in Circular Cylindrical Sandwich Shells With a Three-Layered Viscoelastic Composite Core

Journal of Vibration and Acoustics ◽

10.1115/1.4036868 ◽

2017 ◽

Vol 139 (6) ◽

Cited By ~ 3

Author(s):

Ambesh Kumar ◽

Satyajit Panda

Keyword(s):

Composite Layer ◽

Middle Surface ◽

Layered Composite ◽

Fe Model ◽

Sandwich Shell ◽

Cylindrical Sandwich Shell ◽

Viscoelastic Composite ◽

Damping Characteristics ◽

Viscoelastic Core ◽

Viscoelastic Layers

In this work, the damping characteristics of circular cylindrical sandwich shell with a three-layered viscoelastic composite core are investigated. The new composite core is composed of the identical inclusions of graphite-strips which are axially embedded within a cylindrical viscoelastic core at its middle surface. The physical configuration of the composite core is attributed in the form of a cylindrical laminate of two identical monolithic viscoelastic layers over the inner and outer cylindrical surfaces of middle viscoelastic composite layer so that it is a three-layered viscoelastic composite core. A finite element (FE) model of the overall shell is developed based on the layerwise deformation theory and Sander's shell theory. Using this FE model, the damping characteristics of the shell are studied within an operating frequency range after configuring the size and circumferential distribution of graphite-strips in optimal manner. The numerical results reveal significantly improved damping in the sandwich shell for the use of present three-layered composite core instead of traditional single-layered viscoelastic core. It is also found that the three-layered core provides the advantage in achieving damping at different natural modes as per their assigned relative importance while it is impossible in the use of single-layered viscoelastic core.

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Augmented constrained layer damping in plates through the optimal design of a 0-3 viscoelastic composite layer

Journal of Vibration and Control ◽

10.1177/1077546318756502 ◽

2018 ◽

Vol 24 (23) ◽

pp. 5514-5524 ◽

Cited By ~ 3

Author(s):

Ambesh Kumar ◽

Satyajit Panda ◽

Vivek Narsaria ◽

Ashish Kumar

Keyword(s):

Composite Layer ◽

Shear Deformation Theory ◽

Viscoelastic Layer ◽

Damping Capacity ◽

Geometrical Parameters ◽

Fe Model ◽

Constrained Layer Damping ◽

Rectangular Array ◽

Viscoelastic Composite ◽

Over The Top

In this work, a new 0-3 viscoelastic composite (VEC) layer is presented for augmented constrained layer damping of plate vibration. The 0-3 VEC layer comprises a rectangular array of the thin rectangular graphite-wafers embedded within the viscoelastic matrix. The inclusions of graphite-wafers in the constrained 0-3 VEC layer confine the motion of the viscoelastic phase for its reasonable in-plane strains along with the enhanced transverse shear strains. This occurrence of coincidental shear and extensional strains within the viscoelastic phase is supposed to cause augmented damping capacity of the constrained layer, and it is investigated by integrating the constrained 0-3 VEC layer over the top surface of a substrate plate. A finite element (FE) model of the overall plate is developed based on the layer-wise shear deformation theory. Using this FE model, first, a bending analysis of the overall plate is performed to investigate the mechanisms of damping in the use of 0-3 VEC layer. Next, the damping in the overall plate is quantified for different sets of values of the geometrical parameters of the 0-3 VEC layer. These results reveal significant improvement of damping in the plate due to the inclusions of graphite-wafers within the constrained viscoelastic layer. But, the augmentation of damping indicatively depends on the geometrical parameters in the arrangement of the graphite-wafers. So, the 0-3 VEC layer is configured appropriately through an optimization algorithm, and finally, the forced frequency responses of the overall plate are evaluated to demonstrate the augmented attenuation of vibration-amplitude via the inclusions of graphite-wafers within the constrained viscoelastic layer in an optimal manner.

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Damping treatment of beam with unconstrained/constrained 1-3 smart viscoelastic composite layer

Materials Today Proceedings ◽

10.1016/j.matpr.2020.01.154 ◽

2020 ◽

Vol 26 ◽

pp. 956-962

Author(s):

Abhay Gupta ◽

Rajidi Shashidhar Reddy ◽

Satyajit Panda ◽

Nitin Kumar

Keyword(s):

Composite Layer ◽

Viscoelastic Composite

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Operando Visualization of Morphological Dynamics in All-Solid-State Batteries

10.26434/chemrxiv.8299406 ◽

2019 ◽

Author(s):

Xiaohan Wu ◽

Juliette Billaud ◽

Iwan Jerjen ◽

Federica Marone ◽

Yuya Ishihara ◽

...

Keyword(s):

Solid State ◽

Solid Electrolytes ◽

Rational Design ◽

Morphological Evolution ◽

Active Material ◽

Composite Layer ◽

Transference Number ◽

Thermal Stabilities ◽

Solid State Batteries ◽

All Solid State Batteries

<div> <div> <div> <p>All-solid-state batteries are considered as attractive options for next-generation energy storage owing to the favourable properties (unit transference number and thermal stabilities) of solid electrolytes. However, there are also serious concerns about mechanical deformation of solid electrolytes leading to the degradation of the battery performance. Therefore, understanding the mechanism underlying the electro-mechanical properties in SSBs are essentially important. Here, we show three-dimensional and time-resolved measurements of an all-solid-state cell using synchrotron radiation x-ray tomographic microscopy. We could clearly observe the gradient of the electrochemical reaction and the morphological evolution in the composite layer. Volume expansion/compression of the active material (Sn) was strongly oriented along the thickness of the electrode. While this results in significant deformation (cracking) in the solid electrolyte region, we also find organized cracking patterns depending on the particle size and their arrangements. This study based on operando visualization therefore opens the door towards rational design of particles and electrode morphology for all-solid-state batteries. </p> </div> </div> </div>

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Human Dentine Remineralization Under Non-colagen Materials Action

Revista de Chimie ◽

10.37358/rc.17.5.5583 ◽

2017 ◽

Vol 68 (5) ◽

pp. 928-932

Author(s):

Agripina Zaharia ◽

Viorica Ghisman Plescan ◽

Elena Maria Anghel ◽

Viorica Musat

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Artificial Saliva ◽

Composite Layer ◽

X Ray ◽

Micro Raman Spectroscopy ◽

Agarose Hydrogel ◽

Human Dentine ◽

Dentine Surface ◽

Scanning Electron

The purpose of this work is to induce biomimetic remineralization of acid etched coronal human dentine in artificial saliva (AS) under agarose (A) hydrogel or chitosan (CS)-A hydrogel action. The investigations focused on the morphology, chemical composition and crystalline structure of the new remineralized layers grown onto the etched dentinal surface (R) using scanning electron microscopy coupled with energy dispersive X-ray spectrometry and micro-Raman spectroscopy. Experimental results showed that remineralized layers grown in the presence of A or CS-A hydrogels consist in B-type Ca-deficient hydroxyapatite (HAP). After 7 days treatment into artificial saliva under agarose hydrogel, nanorod-like extrafibrilar HAP crystals randomly self-assembled in a discontinuous layer were formed, while in presence of chitosan-agarose hydrogel a continuous compact CS-HAP composite layer was obtained. The new biomimetic layer (A-CS4) formed after 4 days on dentine surface under A-CS hydrogel has higher crystallinity. Longer exposed (7 days) dentine in the presence of agarose hydrogel shows a higher mineral-to-collagen ratio (A7). Since dentine mineralization increases, the collagen quality factor decreases in succession A-CS4]R]A7. Results show a benefic effect of chitosan on remineralization of etched dentine.

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