Shear actuation-based hybrid damping treatment of sandwich structures using a graphite particle-filled viscoelastic layer

2021 ◽  
pp. 1045389X2110026
Author(s):  
Abhay Gupta ◽  
Satyajit Panda ◽  
Rajidi Shashidhar Reddy
Keyword(s):  
Graphite Particle ◽  
Sandwich Plate ◽  
Volume Fraction ◽  
Shear Mode ◽  
Passive Damping ◽  
Graphite Particles ◽  
The Core ◽  
Active Layers ◽  
Plate Strip ◽  
Hybrid Damping

In this work, the effectiveness of a shear actuation-based hybrid active-passive damping treatment is investigated by incorporating the inclusion of graphite particles within the viscoelastic damping layer. The study is performed through the flexural vibration analysis of a sandwich plate-strip where the core is made of a laminate of active layers and graphite particle-filled viscoelastic layers in two different stacking sequences. The active layers are comprised of shear mode piezoelectric actuator patches that are activated according to a shear-based velocity feedback control strategy. The analysis is performed by deriving a closed-loop finite element model of the sandwich plate-strip, and it reveals that the hybrid damping is significantly dependent on the stacking sequence of active and passive damping layers at the core. The inclusion of graphite particles not only provides augmented passive damping but also causes enhanced transfer of shear actuation force from the active layers to other layers. As a result, a significantly improved shear actuation-based hybrid active-passive damping is achieved due to the inclusion. The effectiveness of this hybrid damping in attenuation of resonant displacement-amplitude is also presented by configuring the volume fraction of graphite particles and shear actuator patches in an optimal manner.

An actively constrained viscoelastic layer with the inclusion of dispersed graphite particles for control of plate vibration

2020 ◽  
pp. 107754632095653
Author(s):  
Abhay Gupta ◽  
Satyajit Panda ◽  
Rajidi S Reddy
Keyword(s):  
Viscoelastic Material ◽  
Piezoelectric Layer ◽  
Volume Fraction ◽  
Effective Properties ◽  
Composite Layer ◽  
Particulate Composite ◽  
Viscoelastic Layer ◽  
Passive Damping ◽  
Graphite Particles ◽  
Material Layer

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.

scholarly journals Free Vibration Analysis of Functionally Gradient Sandwich Composite Plate Embedded SMA Wires in Surface Layer

2020 ◽  
Vol 10 (11) ◽  
pp. 3921
Author(s):  
Yizhe Huang ◽  
Lin Li ◽  
Zhichao Xu ◽  
Chaopeng Li ◽  
Kuanmin Mao
Keyword(s):  
Surface Layer ◽  
Dynamic Behavior ◽  
Composite Plate ◽  
Sandwich Plate ◽  
Volume Fraction ◽  
Core Layer ◽  
Sandwich Composite ◽  
Composition Gradient ◽  
Gradient Distribution ◽  
The Core

In this paper, a new type of composite gradient sandwich plate structure is proposed, which embeds the pre-strained shape memory alloy (SMA) into the surface layer and the core layer composed of epoxy resin and graphite-reinforced materials. In the core layer, graphite-reinforced material has a continuous gradient distribution along the thickness direction of the sandwich plate. Dynamic behavior of composite gradient sandwich plate in thermal environment is investigated. The equations of motion and frequency equation are derived based on the Reddy shear deformation theory and the constitutive equation for a composite sandwich plate, via the Hamilton principle. Some analytical study is depicted to provide an insight into the effects of volume fraction of material composition, gradient distribution of graphite in the core layer, and pre-strain of SMA in the surface layer on the dynamic behavior of a sandwich composite plate. This study investigates the modal performance of a sandwich composite plate with two aspects, a gradient core layer of graphite-reinforced material and surface layer-embedded SMA wires, which provide a new design idea for dynamic behavior of sandwich plates.

Free Vibration and Instability Analysis of Sandwich Plates with Carbon Nanotubes-Reinforced Composite Faces and Honeycomb Core

2021 ◽  
Author(s):  
Sushila Chowdhary ◽  
Mesfin Kebede Kassa ◽  
Yitbarek Gashaw Tadesse ◽  
Ananda Babu Arumugam ◽  
Rajeshkumar Selvaraj
Keyword(s):  
Finite Element ◽  
Glass Fiber ◽  
Sandwich Plate ◽  
Natural Frequencies ◽  
Element Formulation ◽  
The Core ◽  
Glass Fiber Reinforced ◽  
End Conditions ◽  
Honeycomb Sandwich ◽  
Instability Regions

In this study, the instability regions of a honeycomb sandwich plate are investigated for different end conditions under periodic in-plane loading. The core layer of the sandwich plate is made of carbon nanotube (CNT)/glass fiber-reinforced honeycomb and the face layers of CNT/glass fiber- reinforced laminated composite. The governing equations are derived using classical laminated plate theory (CLPT) and solved numerically by using finite element formulation. The effectiveness of the developed finite element formulation is demonstrated by comparing the results in terms of natural frequencies with those available in the literature. The effects of CNT wt.% on the core material, CNT wt.% on the skin material, ply orientation and various end conditions on the variation of natural frequencies, loss factors and instability regions are studied. Finally, some inferences for the effects of CNT reinforcement on the honeycomb sandwich plate subjected to the periodic in-plane loads are discussed.

Natural Convection Inside a Bidisperse Porous Medium Enclosure

2009 ◽  
Vol 132 (1) ◽  
Author(s):  
Arunn Narasimhan ◽  
B. V. K. Reddy
Keyword(s):  
Heat Transfer ◽  
Porous Medium ◽  
Natural Convection ◽  
Volume Fraction ◽  
Solid Phase ◽  
Darcy Number ◽  
The Core ◽  
Side Walls ◽  
Porous Blocks ◽  
Rayleigh Numbers

Bidisperse porous medium (BDPM) consists of a macroporous medium whose solid phase is replaced with a microporous medium. This study investigates using numerical simulations, steady natural convection inside a square BDPM enclosure made from uniformly spaced, disconnected square porous blocks that form the microporous medium. The side walls are subjected to differential heating, while the top and bottom ones are kept adiabatic. The bidispersion effect is generated by varying the number of blocks (N2), macropore volume fraction (ϕE), and internal Darcy number (DaI) for several enclosure Rayleigh numbers (Ra). Their effect on the BDPM heat transfer (Nu) is investigated. When Ra is fixed, the Nu increases with an increase in both DaI and DaE. At low Ra values, Nu is strongly affected by both DaI and ϕE. When N2 is fixed, at high Ra values, the porous blocks in the core region have negligible effect on the Nu. A correlation is proposed to evaluate the heat transfer from the BDPM enclosure, Nu, as a function of Raϕ, DaE, DaI, and N2. It predicts the numerical results of Nu within ±15% and ±9% in two successive ranges of modified Rayleigh number, RaϕDaE.

Vibration control of sandwich plate–reinforced nanocomposite face sheet and porous core integrated with sensor and actuator layers using perturbation method

2020 ◽  
pp. 107754632094833 ◽  
Author(s):  
Rasoul Rostami ◽  
Mehdi Mohammadimehr
Keyword(s):  
Carbon Nanotube ◽  
Perturbation Method ◽  
Vibration Control ◽  
Sandwich Plate ◽  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Face Sheet ◽  
Scale Transformation ◽  
Nonlinear Frequency ◽  
Porous Core

In this article, the vibration control of the sandwich plate reinforced by carbon nanotube in the face sheet and porous core integrated with sensor and actuator layers is investigated. The piezoelectric layers at the bottom and top surfaces of the sandwich plate play the role of the sensor and actuator. By applying the Hamilton’s principle, the governing equations of the structure are derived based on the first-order shear deformation theory. The perturbation method is used to find the relationships between nonlinear frequency and amplitude response of the sandwich plate. The effect of porosity coefficient, temperature, volume fraction of carbon nanotube, and geometric parameters on nonlinear frequency and vibration control of the sandwich plate is studied. Moreover, the influence of material type of sensor and actuator and scale transformation parameter on the nonlinear frequency and vibration control of the system is investigated. According to the obtained results, in the case of ε < 0, the system stiffness presents softening behavior, whereas in the case of ε > 0, the system stiffness becomes hardening. By considering the effect of the voltage coefficient on the vibration control and the needed time for stabilization, the results of this article can be used to design, manufacture, and control modern structures.

Active-passive damping in functionally graded sandwich plate/shell structures

2018 ◽  
Vol 202 ◽  
pp. 324-332 ◽  
Author(s):  
José S. Moita ◽  
Aurélio L. Araújo ◽  
Victor Franco Correia ◽  
Cristóvão M. Mota Soares ◽  
José Herskovits
Keyword(s):  
Sandwich Plate ◽  
Functionally Graded ◽  
Shell Structures ◽  
Passive Damping

Mechanical Deformation of Field-Coupled Materials

2002 ◽  
Author(s):  
Pavel M. Chaplya ◽  
Geoffrey P. McKnight ◽  
Gregory P. Carman
Keyword(s):  
Shape Memory ◽  
Smart Materials ◽  
Residual Strain ◽  
Applied Load ◽  
Mechanical Response ◽  
Volume Fraction ◽  
Mechanical Deformation ◽  
Passive Damping ◽  
Wide Range ◽  
Internal States

This article describes remarkable similarities in the nonlinear mechanical response of different active/smart materials despite fundamental differences in the underlying mechanisms associated with each material. Active/smart materials (i.e., piezoelectric (PZT-5H), magnetostrictive (Terfenol-D), and shape memory alloys (NiTi)) exhibit strong non-linear mechanical behavior produced by changing non-mechanical internal states such as polarization, magnetization, and phase/twin configuration. In active/smart materials the initial deformation proceeds linearly followed by a jump in strain associated with the transformation of an internal non-mechanical state. After the transformation, the mechanical response returns to linear elastic. Upon unloading, a residual strain is observed which can be recovered with the application of a corresponding external field (i.e., electric, magnetic, or thermal). Due to coupling between applied fields and non-mechanical internal states, mechanical deformation is also a function of applied external fields. At a critical applied field, the residual strain is eliminated, providing repeatable cyclic characteristics that can be used in passive damping applications. Even though different intrinsic processes (i.e., polarization, magnetization, and phase/twin variant composition) govern the deformation of each material, their macroscopic behavior is explained using a unified volume fraction concept. That is, the deformation of piezoelectric material is described in terms of the volume fraction of ferroelectric domains with polarization parallel or orthogonal to the applied load; the deformation of magnetostrictive materials is described in terms of the volume fraction of magnetic domains with magnetization parallel or orthogonal to the applied load; and the deformation of shape memory material is described in terms of the volume fraction of twin variants that are oriented favorably to the applied load. Although the qualitative behavior of each material is similar, the average magnitude of stress required to induce non-linearity varies from ~10 MPa for Terfenol-D to ~65 MPa for PZT-5H to ~300 MPa for NiTi shape memory alloy. It is hypothesized that a composite material made of these materials connected in series would exhibit passive damping over a wide range of applied stress.

scholarly journals Finite Element Analysis of Dynamic Recrystallization of Casting Slabs during Hot-Core Heavy Reduction Rolling Process

Metals ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 181
Author(s):  
Haijun Li ◽  
Tianxiang Li ◽  
Meina Gong ◽  
Zhaodong Wang ◽  
Guodong Wang
Keyword(s):  
Grain Size ◽  
Dynamic Recrystallization ◽  
Volume Fraction ◽  
Rolling Process ◽  
Reduction Ratio ◽  
Secondary Development ◽  
Innovative Technology ◽  
Element Analysis ◽  
The Core ◽  
Average Grain Size

Hot-core heavy reduction rolling (HHR2) is an innovative technology, where a two-high rolling mill is installed after the solidification end of a strand, which can significantly eliminate the core defects of the slab. The mill exhibits a heavy reduction ratio, which promotes the dynamic recrystallization (DRX) of the slab. This study aims to optimize the parameters of the HHR2 process considering the effect of DRX on microstructure homogeneity. The secondary development of commercial software DEFORM-3D is conducted to calculate the deformation and DRX behavior of HHR2 for different reduction ratios. The parameters of DRX volume fraction and DRX grain size are compared, and finer DRX grains are obtained when the greater reduction ratios are conducted in HHR2. Then, corresponding to the deformation conditions in the HHR2, the thermal–mechanical simulations are conducted on the Gleeble3800 to obtain the average grain sizes before and after this process. When the reduction amount increases from 20 mm to 50 mm, the difference of average grain size between the core and the surface reduces by 52%. In other words, appropriately enhancing the reduction ratio is helpful to reduce the average austenite grain and promote the microstructure uniformity of the slab. These results provide some valuable information on the design of deformation parameters for HHR2.

Electric field effect on dynamic analysis of smart porosity-dependent nanocomposite sandwich plate resting on silica aerogel foundation considering carbon nanotubes agglomeration

2019 ◽  
Vol 30 (18-19) ◽  
pp. 2651-2669
Author(s):  
Mohammad Hossein Zamani ◽  
Mohammad Heidari-Rarani ◽  
Alireza Ariaei
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Silica Aerogel ◽  
Sandwich Plate ◽  
Core Layer ◽  
Smart Structure ◽  
Geometrical Parameters ◽  
Equivalent Material ◽  
Electric Field Effect ◽  
The Core

In this study, the influence of carbon nanotubes agglomeration is investigated on the electroelastic dynamic behavior of a sandwich plate. The smart sandwich plate consists of functionally graded porous layer as the core and piezoelectric layers as the face sheets, which is subjected to the harmonic electrical loading. In order to take into account the continuum model for the silica aerogel foundation of the smart structure, the modified Vlasov’s model is applied. The porosity distribution of the core layer varies non-uniformly throughout the thickness due to the non-uniform function. The equivalent material properties of nanocomposite core layer are determined using the Eshelby–Mori–Tanaka approach, in which the influence of carbon nanotube agglomeration is considered. For modeling the electroelastic fact sheets behavior, the piezoelasticity theory is adopted. On the basis of non-polynomial shear and normal deformation theory, the governing equations of motion are inferred applying the Hamilton’s principle and the obtained equations are solved by an iterative procedure. The verification is accomplished through the available results in the literature and the influences of carbon nanotube agglomeration, different geometrical parameters, porosity index, and applied voltage are assessed on the dynamic deflection of nanocomposite sandwich plate.

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