Internal Energy Transfer in Dynamical Behavior of Slightly Curved Shear Deformable Microplates

This paper investigates the internal energy transfer and modal interactions in the dynamical behavior of slightly curved microplates. Employing the third-order shear deformation theory, the microplate model is developed taking into account geometric nonlinearities as well as the modified couple stress theory; the initial curvature is modeled by an initial imperfection in the out-of-plane direction. The in-plane displacements and inertia are retained, and the coupled out-of-plane, rotational, and in-plane motion characteristics are analyzed. Specifically, continuous models are developed for kinetic and potential energies as well as damping and external works; these are balanced and reduced via Lagrange's equations along with an assumed-mode technique. The reduced-order model is then solved numerically by means of a continuation technique; stability analysis is performed by means of the Floquet theory. The possibility of the occurrence of modal interactions and internal energy transfers is verified via a linear analysis on different natural frequencies of the system. The nonlinear resonant response of the system is obtained for the cases with internal energy transfer, and energy transfer mechanisms are analyzed; as we shall see, the presence of an initial curvature affects the system dynamics substantially. The importance of taking into account small-size effects is also shown by discovering this fact that both the linear and nonlinear internal energy transfer mechanisms are shifted substantially if this effect is ignored.

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Hygrothermal environment effect on the critical buckling load of FGP microbeams with initial curvature integrated by CNT-reinforced skins considering the influence of thickness stretching

Nanotechnology Reviews ◽

10.1515/ntrev-2021-0076 ◽

2021 ◽

Vol 10 (1) ◽

pp. 1140-1156

Author(s):

Mohammad Alkhedher

Keyword(s):

Couple Stress Theory ◽

Shear Deformation Theory ◽

Functionally Graded ◽

Buckling Load ◽

Polar Coordinates ◽

Curved Beams ◽

Virtual Displacement ◽

Initial Curvature ◽

The Core ◽

Hygrothermal Environment

Abstract Due to the need for structures with refined properties to bear against different loading conditions, recently, carbon nanotubes (CNTs) have been used widely to reinforce them. The extremely high stiffness of CNTs makes them significant as one of the best reinforcements to improve the mechanical behaviors of structures. This work focuses on microbeam buckling response with an initial curvature that includes three layers. The mid-layer that is known as the core is constituted of functionally graded porous (FGP) materials and two CNT-reinforced composite skins are bonded to the core to integrate it. The whole structure is affected by the hygrothermal environment and springs and shear layers are put below it. For the first time, for such a structure, a refined shear deformation theory (RSDT) as a higher-order theory that considers thickness stretching effect in polar coordinates is used that presents more accurate results, especially for deeply curved beams. Modified couple stress theory (MCST) in combination with the virtual displacement principle is utilized to establish the governing equations. The obtained results demonstrate the significance of porosity percentage and CNTs’ addition to the skins on the critical nanotubes buckling load. Also, the different behaviors of the microstructure at various temperatures are analyzed and discussed in detail.

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Ultrafast Electron/Energy Transfer and Intersystem Crossing Mechanisms in BODIPY-Porphyrin Compounds

Processes ◽

10.3390/pr9020312 ◽

2021 ◽

Vol 9 (2) ◽

pp. 312

Author(s):

Yusuf Tutel ◽

Gökhan Sevinç ◽

Betül Küçüköz ◽

Elif Akhuseyin Yildiz ◽

Ahmet Karatay ◽

...

Keyword(s):

Energy Transfer ◽

Fluorescence Spectra ◽

Visible Region ◽

Energy Transfer Mechanism ◽

Free Base ◽

Pump Probe ◽

Harvesting Efficiency ◽

Probe Spectroscopy ◽

Absorption Features ◽

Transfer Mechanisms

Meso-substituted borondipyrromethene (BODIPY)-porphyrin compounds that include free base porphyrin with two different numbers of BODIPY groups (BDP-TTP and 3BDP-TTP) were designed and synthesized to analyze intramolecular energy transfer mechanisms of meso-substituted BODIPY-porphyrin dyads and the effect of the different numbers of BODIPY groups connected to free-base porphyrin on the energy transfer mechanism. Absorption spectra of BODIPY-porphyrin conjugates showed wide absorption features in the visible region, and that is highly valuable to increase light-harvesting efficiency. Fluorescence spectra of the studied compounds proved that BODIPY emission intensity decreased upon the photoexcitation of the BODIPY core, due to the energy transfer from BODIPY unit to porphyrin. In addition, ultrafast pump-probe spectroscopy measurements indicated that the energy transfer of the 3BDP-TTP compound (about 3 ps) is faster than the BDP-TTP compound (about 22 ps). Since the BODIPY core directly binds to the porphyrin unit, rapid energy transfer was seen for both compounds. Thus, the energy transfer rate increased with an increasing number of BODIPY moiety connected to free-base porphyrin.

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Energy transfer mechanisms and resolvent analysis in the cylinder wake

Physical Review Fluids ◽

10.1103/physrevfluids.6.024702 ◽

2021 ◽

Vol 6 (2) ◽

Author(s):

Bo Jin ◽

Sean Symon ◽

Simon J. Illingworth

Keyword(s):

Energy Transfer ◽

Cylinder Wake ◽

Transfer Mechanisms

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Energy transfer mechanisms in laser-induced plasmas: Variation of physical traits mediated by the presence of single optically-trapped nanoparticulate material

Spectrochimica Acta Part B Atomic Spectroscopy ◽

10.1016/j.sab.2021.106193 ◽

2021 ◽

pp. 106193

Author(s):

Francisco J. Fortes ◽

Pablo Purohit ◽

J. Javier Laserna

Keyword(s):

Energy Transfer ◽

Physical Traits ◽

Optically Trapped ◽

Transfer Mechanisms

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The afterglow and energy transfer mechanisms of active nitrogen

Reports on Progress in Physics ◽

10.1088/0034-4885/33/1/306 ◽

1970 ◽

Vol 33 (1) ◽

pp. 269-306 ◽

Cited By ~ 33

Author(s):

J Anketell ◽

R W Nicholls

Keyword(s):

Energy Transfer ◽

Active Nitrogen ◽

Transfer Mechanisms

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In-plane and out-of-plane motion characteristics of microbeams with modal interactions

Composites Part B Engineering ◽

10.1016/j.compositesb.2013.12.074 ◽

2014 ◽

Vol 60 ◽

pp. 423-439 ◽

Cited By ~ 170

Author(s):

Mergen H. Ghayesh ◽

Hamed Farokhi ◽

Marco Amabili

Keyword(s):

Plane Motion ◽

Modal Interactions ◽

Out Of Plane ◽

Motion Characteristics

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Size-dependent bending behavior of three-layered doubly curved shells: Modified couple stress formulation

Journal of Sandwich Structures & Materials ◽

10.1177/1099636218793993 ◽

2018 ◽

Vol 22 (7) ◽

pp. 2210-2249 ◽

Cited By ~ 3

Author(s):

Mohammad Arefi

Keyword(s):

Applied Voltage ◽

Couple Stress ◽

Virtual Work ◽

Couple Stress Theory ◽

Shear Deformation Theory ◽

Small Scale ◽

Size Dependent ◽

Modified Couple Stress ◽

Doubly Curved ◽

Piezoelectric Shell

In this paper, modified couple stress formulation of a small scale doubly curved piezoelectric shell resting on Pasternak's foundation is presented based on first-order shear deformation theory. Size-dependent electro-elastic results of doubly curved shell are presented based on an analytical approach. The doubly curved piezoelectric shell is subjected to uniform transverse loads and applied voltage. To account the size dependency, modified couple stress theory is employed in conjunction with principle of virtual work. The numerical results are presented in both tabular and graphical forms to show the influence of small scale parameter, applied voltage, geometries and two parameters of Pasternak's foundation on the electro-elastic results of size-dependent doubly curved piezoelectric shell.

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