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Influence of fiber paths on buckling load of tailored conical shells
Ali-Asghar Naderi,Gholam-Hossein Rahimi,Mohammad Arefi 국제구조공학회 2014 Steel and Composite Structures, An International J Vol.16 No.4
The purpose of this paper is to propose a method for evaluation of varying stiffness coefficients of tailored conical shells (TCS). Furthermore, a comparison between buckling loads of these shells under axial load with the different fiber path is performed. A circular truncated conical shell subjected to axial compression is taken into account. Three different theoretical path containing geodesic path, constant curvature path and constant angle path has been considered to describe the angle variation along the cone length, along cone generator of a conical shell are offered. In the TCS with the arbitrary fiber path, the thickness and the ply orientation are assumed to be functions of the shell coordinates and influencing stiffness coefficients of the structure. The stiffness coefficients and the buckling loads of shells are calculated basing on classical shells theory (CST) and using finite-element analysis (FEA) software. The obtained results for TCS with arbitrary fiber path, thickness and ply orientation are derived as functions of shell longitudinal coordinate and influencing stiffness coefficients of structures. Furthermore, the buckling loads based on fiber path and ply orientation at the start of tailored fiber get to be different. The extent of difference for tailored fiber with start angle lower than 20 degrees is not significant. The results in this paper show that using tailored fiber placement could be applied for producing conical shells in order to have greater buckling strengths and lower weight. This work demonstrates the use of fiber path definitions for calculated stiffness coefficients and buckling loads of conical shells.
Ali, Asghar,Oh, Won-Chun The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.6
We examined the photo catalytic activity and catalytic recyclability of CdSe/graphene nanocomposites fabricated via modified hydrothermal technique. The prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Raman spectroscopic analysis, and X-ray photoelectron spectroscopy (XPS). The photocatalytic behavior was investigated through decomposition of RBB as a standard dye under visible light radiation. Our results indicate that there is significant potential for graphene based semiconductor hybrids materials to be used as photocatalysts under visible light irradiation for the degradation of organic dyes from industry effluents.
Ali Asghar Shojaei,Mohd Fauzi Othman,Masoud Samadi 제어로봇시스템학회 2015 제어로봇시스템학회 국제학술대회 논문집 Vol.2015 No.10
Flexible AC transmission system devices are used in power transmission networks in order to increase the maximum power transmission and stability. They as well, help to damp low frequency oscillations for both local and internal areas. On the other hand, the design of these devices with uncoordinated Power System Stabilizer (PSS) may degrade the performance of the power system. In addition, the power systems are vast, complex and nonlinear. Linear control strategies do not have a satisfactory performance for these systems, especially when some disturbances occur. In this study a nonlinear control strategy based on Recurrent Neural Network (RNN) is designed to control PSS and ASMES for a standard power system. The results demonstrate that the proposed coordinated control strategy based on RNN lead to improvement in stability of frequency and terminal voltage responses of the generator.
Asghar Ali,오원춘 한국세라믹학회 2015 한국세라믹학회지 Vol.52 No.6
We examined the photo catalytic activity and catalytic recyclability of CdSe/graphene nanocomposites fabricated via modified hydrothermal technique. The prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Raman spectroscopic analysis, and X-ray photoelectron spectroscopy (XPS). The photocatalytic behavior was investigated through decomposition of RBB as a standard dye under visible light radiation. Our results indicate that there is significant potential for graphene based semiconductor hybrids materials to be used as photocatalysts under visible light irradiation for the degradation of organic dyes from industry effluents.
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,Ta Techno-Press 2020 Advances in concrete construction Vol.10 No.4
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.
Ali Asghar Atai,Mohammad Hassan Naei,Reza Eghtefari 대한기계학회 2010 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.24 No.11
Snap-through is an instability phenomenon that occurs in arch and dome-shaped structures, wherein the structure has to move from a stable equilibrium state through an unstable path into another stable equilibrated configuration in a jumping action. In this study, a linear elastic isotropic low arch is considered as a structure with power-law variable thickness. The phenomenon is investigated by considering the equation of the deflection for the variable thickness arch, solving it with an elegant analytical technique, and finding the snap-through critical load from an extreme condition. The effect of power-law exponent and geometry of the arch centerline on critical load is investigated and the constant thickness case and a very rare case of power-law thickness variation found in literature are considered for verification.
LASER INDUCED SURFACE PROCESSING WITH GOLD NANOPARTICLE ARRAYS EMBEDDED IN A TRANSPARENT MATRIX
ALI ASGHAR ASKARI,ALI REZA BAHRAMPOUR 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.1
Gold nanoparticles are widely used as high efficient photon–thermal energy converters in a broad range of applications. This paper presents a theoretical investigation on using the optothermal properties of gold nanoparticle arrays to generate nanoscale molten and rubbery regions on the surface of an amorphous polymeric film. Nanoparticles are assumed to be embedded in a transparent silica layer and illuminated with a 7.5 ns pulsed laser at 532 nm. Simulation results are presented for systems with single gold nanoparticles, dimers and chains. Both electromagnetic and thermal interaction between nanoparticles are found to be important factors in determining the result of surface processing. This effect allows us to control the shape and spatial characteristics of the phase transmitted regions with various parameters such as particles size, incident light fluence, polarization and direction, interparticle distance and chain length.