• Title/Summary/Keyword: double-shell

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Nonlocal vibration of DWCNTs based on Flügge shell model using wave propagation approach

  • Asghar, Sehar;Naeem, Muhammad N.;Hussain, Muzamal;Tounsi, Abdelouahed
    • Steel and Composite Structures
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    • v.34 no.4
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    • pp.599-613
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    • 2020
  • In this article, free vibration attributes of double-walled carbon nanotubes based on nonlocal elastic shell model have been investigated. For this purpose, a nonlocal Flügge shell model is established to observe the small scale effect. The wave propagation is employed to frame the governing equations as eigenvalue system. The influence of nonlocal parameter subjected to different end supports has been overtly examined. A suitable choice of material properties and nonlocal parameter been focused to analyze the vibration characteristics. The new set of inner and outer tubes radii investigated in detail against aspect ratio and length. The dominance of boundary conditions via nonlocal parameter is shown graphically. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

Buckling analysis of double walled carbon nanotubes embedded in Kerr elastic medium under axial compression using the nonlocal Donnell shell theory

  • Timesli, Abdelaziz
    • Advances in nano research
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    • v.9 no.2
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    • pp.69-82
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    • 2020
  • In this paper, a new explicit analytical formula is derived for the critical buckling load of Double Walled Carbon Nanotubes (DWCNTs) embedded in Winkler elastic medium without taking into account the effects of the nonlocal parameter, which indicates the effects of the surrounding elastic matrix combined with the intertube Van der Waals (VdW) forces. Furthermore, we present a model which predicts that the critical axial buckling load embedded in Winkler, Pasternak or Kerr elastic medium under axial compression using the nonlocal Donnell shell theory, this model takes into account the effects of internal small length scale and the VdW interactions between the inner and outer nanotubes. The present model predicts that the critical axial buckling load of embedded DWCNTs is greater than that without medium under identical conditions and parameters. We can conclude that the embedded DWCNTs are less susceptible to axial buckling than those without medium.

3D Hierarchical Heterostructure of TiO2 Nanorod/Carbon Layer/NiMn-Layered Double Hydroxide Nanosheet

  • Zhao, Wei;Jung, Hyunsung
    • Journal of the Korean institute of surface engineering
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    • v.51 no.6
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    • pp.365-371
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    • 2018
  • 1D core-shell nanostructures have attracted great attention due to their enhanced physical and chemical properties. Specifically, oriented single-crystalline $TiO_2$ nanorods or nanowires on a transparent conductive substrate would be more desirable as the building core backbone. However, a facile approach to produce such structure-based hybrids is highly demanded. In this study, a three-step hydrothermal method was developed to grow NiMn-layered double hydroxide-decorated $TiO_2$/carbon core-shell nanorod arrays on transparent conductive fluorine-doped tin oxide (FTO) substrates. XRD, SEM, TEM, XPS and Raman were used to analyze the obtained samples. The in-situ fabricated hybrid nanostructured materials are expected to be applicable for photoelectrode working in water splitting.

Baroplastic Properties of Core-double Shell Type Nanoparticles Consisting of Crosslinked PS as a Core and PBA and PS as Shells (가교된 PS 코어와 PBA 및 PS 셸로 이루어진 코어-더블셸형 나노입자의 압력가소성)

  • Park, Ji-Young;Ryu, Sang-Woog
    • Polymer(Korea)
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    • v.38 no.1
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    • pp.80-84
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    • 2014
  • Polymer nanoparticles with cross-linked core and PBA/PS double-shell were synthesized and their baroplastic properties were characterized. PBA/PS, the inner and outer shell with cross-linked core consisting of St and DVB were synthesized by three-stage emulsion polymerization. The obtained materials exhibited pressure-induced mixing of their components and could be processed at $25^{\circ}C$ by compression molding which means there was no effect of the presence of cross-linked core. Interestingly, the Young's modulus of molded objects has found to be affected strongly by the size of double-shell nanoparticles. Furthermore, the molded object of higher PBA content was successfully recycled 5 times at $25^{\circ}C$ and showed 0.55 MPa of modulus and 1.81 MPa of strength at break.

Structural detection of variation in Poisson's ratio: Monitoring system for zigzag double walled carbon nanotubes

  • Hussain, Muzamal;Asghar, Sehar;Ayed, Hamdi;Khadimallah, Mohamed A.;Alshoaibi, Adil;Tounsi, Abdelouahed
    • Advances in nano research
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    • v.12 no.4
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    • pp.345-352
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    • 2022
  • In this paper, natural frequency curves are presented for three specific end supports considering distinct values of nonlocal parameter. The vibrational behavior of zigzag double walled carbon nanotubes is investigated using wave propagation with nonlocal effect. Frequency spectra of zigzag (12, 0) double walled carbon nanotubes have been analyzed with proposed model. Effects of nonlocal parameters have been fully investigated on the natural frequency against against variation of Poisson's ratio. A slow increase in frequencies against variation of Poisson's ratio also indicates insensitivity of it for suggested nonlocal model. Moreover, decrease in frequencies with increase in nonlocal parameter authenticates the applicability of nonlocal Love shell model. Also the frequency curves for C-F are lower throughout the computation than that of C-C curves.

A Study on the Thermal Distortion Analysis of Welded Structures having K/X Groove using shell elements (쉘 요소를 이용한 K및 X개선 용접구조물의 열변형 해석방법에 관한 연구)

  • Ha, Yunsok;Choi, Jiwon
    • Journal of Welding and Joining
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    • v.30 no.6
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    • pp.120-125
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    • 2012
  • Because ships and offshore structures have very large dimensions and complicated shapes, it is difficult to determine the deformation or internal stress in the structure by simple lab tests. Thus, a rigorous analysis by using the computer simulation technology is essential for obtaining their distortions by considering the entire production process characteristics. The rapid development of computer technology made it possible to analyze the heat transfer phenomena, deformation and phase transformation in the welded joint. For large shell structures, shell elements modeling contributed primarily to this development. But if a welding is done by multi-pass, shell elements whose thickness are unchangeable can hard to describe the local situation. Recently, it was researched how to introduce the imaginary temperature for V grooved multi-layer butt welding in strain-boundary method (a kind of shrinkage methodologies). In the present study, we formulated the imaginary temperature for the double bevel and double V groove by considering the thickness change of each pass through the bead and the thickness directions simultaneously and also demonstrated the feasibility of the formula by applying it to the thermal distortion analysis of the erection process of crane pedestal.

Small scale computational vibration of double-walled CNTs: Estimation of nonlocal shell model

  • Asghar, Sehar;Khadimallah, Mohamed Amine;Naeem, Muhammad N.;Ghamkhar, Madiha;Khedher, Khaled Mohamed;Hussain, Muzamal;Bouzgarrou, Souhail Mohamed;Ali, Zainab;Iqbal, Zafar;Mahmoud, S.R.;Algarni, Ali;Taj, Muhammad;Tounsi, Abdelouahed
    • Advances in concrete construction
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    • v.10 no.4
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    • pp.345-355
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    • 2020
  • In this paper, vibration characteristics of double-walled carbon nanotubes (CNTs) is studied based upon nonlocal elastic shell theory. The significance of small scale is being perceived by developing nonlocal Love shell model. The wave propagation approach has been utilized to frame the governing equations as eigen value system. The influence of nonlocal parameter subjected to diverse end supports has been overtly analyzed. An appropriate selection of material properties and nonlocal parameter has been considered. The influence of changing mechanical parameter Poisson's ratio has been investigated in detail. The dominance of boundary conditions via nonlocal parameter is shown graphically. The results generated furnish the evidence regarding applicability of nonlocal shell model and also verified by earlier published literature.

Development of Remediation and Stabilization Technique for Low-Permeable Contaminated Soil Using Waste Materials (폐기물을 활용한 저투수성 오염토양의 정화 및 안정화 기술 개발)

  • 박상규;이기호;박준범
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.10a
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    • pp.681-688
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    • 2002
  • Study was peformed to develop the‘environmental double pile’for the remediation of low-permeable contaminated soil. This technique is similar in function to‘sand drain pile’But this applies recyclable oyster shell treated as waste materials to a drain material and the pile is consisted of two layers. Inner metal pile is located in center and oyster shells are filled around it. By this technology, contaminated ground water is pumped out through the oyster shell and purified by drainage, adsorption, and reaction processes. Afterwards, the grout material is injected through the inner pile for the effect of the solidification / stabilization. As a result, the concept of this technique is a development of one-step process technology. Through the test, a consolidation characteristic by radial drain is going to be evaluated and the optimum standard of this technology will be calculated.

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Assessment of multi-physical field effects on nonlinear static stability behavior of nanoshells based on a numerical approach

  • Zhanlei Wang;Ye Chen
    • Steel and Composite Structures
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    • v.46 no.4
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    • pp.513-523
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    • 2023
  • Buckling and post-buckling behaviors of geometrically perfect double-curvature shells made from smart composites have been investigated. The shell has been supposed to be exposed to transverse mechanical loading and magneto-electro-elastic (MEE) coupling. The composite shell has been made of two constituents which are piezoelectric and magnetic ingredients. Thus, the elastic properties might be variable based upon the percentages of the constituents. Incorporating small scale impacts in regard to nonlocal theory leads to the establishment of the governing equations for the double-curvature nanoshell. Such nanoshell stability will be shown to be affected by composite ingredients. More focus has been paid to the effects of small scale factor, electric voltage and magnetic intensity on stability curves of the nanoshell.