scholarly journals Vibration analysis of an axially moving multiscale composite plate subjected to thermal loading

2018 ◽  
Vol 148 ◽  
pp. 06003
Author(s):  
Krzysztof Marynowski
Keyword(s):  
Carbon Nanotubes ◽  
Composite Plate ◽  
Thermal Loading ◽  
Free Vibrations ◽  
Copper Plate ◽  
Complex Frequency ◽  
Plate Material ◽  
Multiscale Composite ◽  
Effects Of Temperature ◽  
Axially Moving

This study investigated the effects of temperature on free vibrations and critical transport speeds of an axially moving multiscale composite plate. On the basis of the frequency-temperature equivalence principle, a linear mathematical model of the moving multiscale composite plate is derived in the complex frequency domain. Fractional standard rheological model of the plate material as the function of reduced frequency depended on the temperature is determined. In numerical investigations carbon nanotubes- and graphene-reinforced copper plate was taken into account.. To describe thermomechanical properties of the plate material, the investigation results obtained from the molecular dynamics studies and the experimental characteristic of beryllium copper in low temperatures presented in literature is taken into account.. The effects of temperature, transport speed, and internal damping on natural frequencies and critical transport speed are analyzed. The critical transport speeds of the graphene-reinforced multiscale composite are higher than both carbon nanotubes-reinforced composite as well as the comparable copper alloy.

Effects of temperature on caffeine and carbon nanotubes co-exposure in Ruditapes philippinarum

Chemosphere ◽  
2021 ◽  
Vol 271 ◽  
pp. 129775
Author(s):  
Raffaele Piscopo ◽  
Francesca Coppola ◽  
Ângela Almeida ◽  
Lucia De Marchi ◽  
Tania Russo ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Ruditapes Philippinarum ◽  
Effects Of Temperature

Effects of temperature oscillations on the growth of carbon nanotubes by chemical vapor deposition

2000 ◽  
Vol 76 (7) ◽  
pp. 828-830 ◽  
Author(s):  
L. F. Sun ◽  
S. S. Xie ◽  
J. M. Mao ◽  
Z. W. Pan ◽  
B. H. Chang ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Temperature Oscillations ◽  
Effects Of Temperature

scholarly journals An investigation into the free vibrations of carbon nanotubes using analytical and finite element methods

2021 ◽  
Author(s):  
Ishan Ali Khan
Keyword(s):  
Carbon Nanotubes ◽  
Finite Element ◽  
Eigenvalue Problem ◽  
Natural Frequencies ◽  
Nonlinear Eigenvalue Problem ◽  
Dynamic Stiffness ◽  
Free Vibrations ◽  
Mode Shapes ◽  
Wide Range ◽  
Walled Cnts

Since their discovery, immense attention has been given to carbon nanotubes (CNTs), due to their exceptional thermal, electronic and mechanical properties and, therefore, the wide range of applications in which they are, or can be potentially, employed. Hence, it is important that all the properties of carbon nanotubes are studied extensively. This thesis studies the vibrational frequencies of double-walled and triple-walled CNTs, with and without an elastic medium surrounding them, by using Finite Element Method (FEM) and Dynamic Stiffness Matrix (DSM) formulations, considering them as Euler-Bernoulli beams coupled with van der Waals interaction forces. For FEM modelling, the linear eigenvalue problem is obtained using Galerkin weighted residual approach. The natural frequencies and mode shapes are derived from eigenvalues and eigenvectors, respectively. For DSM formulation of double-walled CNTs, a nonlinear eigenvalue problem is obtained by enforcing displacement and load end conditions to the exact solution of single equation achieved by combining the coupled governing equations. The natural frequencies are obtained using Wittrick-Williams algorithm. FEM formulation is also applied to both double and triple-walled CNTs modelled as nonlocal Euler-Bernoulli beam. The natural frequencies obtained for all the cases, are in agreement with the values provided in literature.

Seawater effects on interlaminar fracture toughness of glass fiber/epoxy laminates modified with multiwall carbon nanotubes

2020 ◽  
pp. 002199832095078
Author(s):  
Julio A Rodríguez-González ◽  
Carlos Rubio-González
Keyword(s):  
Carbon Nanotubes ◽  
Fracture Toughness ◽  
Glass Fiber ◽  
Composite Laminates ◽  
Multiwall Carbon Nanotubes ◽  
Mode I ◽  
Mode Ii ◽  
Interlaminar Fracture Toughness ◽  
Multiscale Composite ◽  
Multiwall Carbon

In this work, the effect of seawater ageing on mode I and mode II interlaminar fracture toughness ([Formula: see text] and [Formula: see text]) of prepreg-based woven glass fiber/epoxy laminates with and without multiwall carbon nanotubes (MWCNTs) has been investigated. The first part of the investigation reports the moisture absorption behavior of multiscale composite laminates exposed to seawater ageing for ∼3912 h at 70 °C. Then, the results of mode I and mode II fracture tests are presented and a comparison of [Formula: see text] and [Formula: see text] for each type of material group and condition is made. Experimental results showed the significant effect of seawater ageing on [Formula: see text] of multiscale composite laminates due to matrix plasticization and fiber bridging. The improvement in [Formula: see text] of the wet glass fiber/epoxy laminate was about 50% higher than that of the neat laminate (without MWCNTs) under dry condition. It was also found that the presence of MWCNTs into composite laminates promotes a moderate increase (8%) in their [Formula: see text] as a result of the additional toughening mechanisms induced by CNTs during the delamination process. Scanning electron microscopy analysis conducted on fracture surface of specimens reveals the transition from brittle (smooth surface) to ductile (rough surface) in the morphology of composite laminates due to the influence of seawater ageing on the polymeric matrix and fiber/matrix interface.

scholarly journals Multiscale Composites: Assessment of a Feasible Manufacturing Process

2019 ◽  
Vol 2019 ◽  
pp. 1-8
Author(s):  
R. Volponi ◽  
P. Spena ◽  
F. De Nicola ◽  
L. Guadagno
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Fiber ◽  
Manufacturing Process ◽  
Resin Transfer Molding ◽  
Fiber Reinforced ◽  
Transfer Molding ◽  
Macro Scale ◽  
Multiscale Composite ◽  
The Matrix ◽  
Carbon Fiber Reinforced

A very interesting field of research on advanced composite materials is the possibility to integrate new functionalities and specific improvements acting on the matrix of the composite by means of a nanocharged resin. In this way, the composite becomes a so-called “multiscale composite” in which the different phases change from nano to macro scale. For example, the incorporation of nanoscale conductive fillers with intrinsically high electrical conductivity could allow a tailoring of this property for the final material. The properties of carbon nanotubes (CNT) make them an effective candidate as fillers in polymer composite systems to obtain ultralight structural materials with advanced electrical and thermal characteristics. Nevertheless, several problems are related to the distribution in the matrix and to the processability of the systems filled with CNT. Existing liquid molding processes such as resin transfer molding (RTM) and vacuum-assisted resin transfer molding (VARTM) can be adapted to produce carbon fiber reinforced polymer (CFRP) impregnated with CNT nanofilled resins. Unfortunately, the loading of more than 0.3-0.5% of CNT can lead to high resin viscosities that are unacceptable for such kind of processes. In addition to the viscosity issues that are related to the high CNT content, a filtration effect of the nanofillers caused by the fibrous medium may also lead to inadequate final component quality. This work describes the development of an effective manufacturing process of a fiber-reinforced multiscale composite panel, with a tetra-functional epoxy matrix loaded with carbon nanotubes to increase its electrical properties and with GPOSS to increase its resistance to fire. A first approach has been attempted with a traditional liquid infusion process. As already anticipated, this technique has shown considerable difficulties related both to the low level of impregnation achieved, due to the high viscosity of the resin, and to the filtration effects of the dispersed nanocharges. To overcome these problems, an opportunely modified process based on a sort of film infusion has been proposed. This modification has given an acceptable result in terms of impregnation and morphological arrangement of CNTs in nanofilled CFRP. Finally, the developed infiltration technique has been tested for the manufacture of a carbon fiber-reinforced panel with a more complex shape.

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