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Showing papers on "Shell (structure) published in 2021"


Journal ArticleDOI
TL;DR: In this article, a composite material with graphene-reinforcement has obtained commercially notices in promoted engineering applications, and it has been used in a number of process manufacturing applications, such as:
Abstract: Due to the rapid development of process manufacturing, composite materials with graphene-reinforcement have obtained commercially notices in promoted engineering applications. For this regard, vibr...

103 citations


Journal ArticleDOI
TL;DR: In this article, the authors developed a size-dependent model to provide a comprehensive analysis of static stability in doubly curved micro-panels resting on an elastic foundation, which is made of advanced composites which reinforced with carbon-based materials.

98 citations


Journal ArticleDOI
TL;DR: In this article, the authors presented a 3D numerical solution for investigating the free vibration and buckling responses of annular plate, conical and cylindrical shell made of functionally graded (FG) porous rock materials.

60 citations


Journal ArticleDOI
TL;DR: In this paper, a power-full higher-order shear-deformation theory in curvilinear coordinate is developed to model the doubly-curved nano-size shell.

49 citations


Journal ArticleDOI
TL;DR: In this paper, the most of previous works through vibroacoustic performance of shell structures in past years (1957-2019) are reviewed with emphasis on the kinds of shells with different geometries containing cylindrical and doubly curved shells.
Abstract: This paper reviews the most of previous works through vibroacoustic performance of shell structures in past years (1957–2019). The major end is especially placed to collate the researches carried out in the area of power transmission through shell structures during the last 60 years. For this purpose, a series of categories are first highlighted in order to classify the issues that should be searched. The review is then directed with emphasis on the kinds of shells with different geometries containing cylindrical and doubly curved shells. Later on, not only a popular discussion is proposed to model the acoustic behavior of shells based on the different theories (classical, shear deformation and three-dimensional) but also a perfect explanation is provided wherein the importance of modeling the structures according to the different materials is revealed. To extend the review, various boundary conditions (finite and infinite) are also investigated. Besides, the further effects of external environments as fluid and thermal are inspected. Since the type of incident field can be impressive on the sound insulation specification of these shells, the structure is characterized based on the various acoustic excitations involving plane wave and point source incidences. Furthermore, some descriptions on the solution procedures (analytical, experimental and numerical) are also given. As a result, the review is centralized through other matters such as control and optimization techniques in order to improve the vibroacoustic behavior of shell structures.

48 citations


Journal ArticleDOI
TL;DR: In this article, an equivalent single layer (ESL) approach is proposed to analyze doubly-curved shells with constant and/or varying thicknesses made of completely anisotropic materials.

47 citations


Journal ArticleDOI
TL;DR: The effectiveness of the present method is demonstrated by validating the obtained results against those of other studies from literature considering shell structures, and some novel numerical results, including the nonlinear transient deflection of smart FG-CNTRC spherical and cylindrical shells, will be presented and can be considered for future structure design.
Abstract: In the present work, a geometrically nonlinear finite shell element is first presented to predict nonlinear dynamic behavior of piezolaminated functionally graded carbon nanotube-reinforced composite (FG-CNTRC) shell, to enrich the existing research results on FG-CNTRC structures. The governing equations are developed via an improved first-order shear deformation theory (FSDT), in which a parabolic distribution of the transverse shear strains across the shell thickness is assumed and a zero condition of the transverse shear stresses on the top and bottom surfaces is imposed. Using a micro-mechanical model on the foundation of the developed rule of mixture, the effective material properties of the FG-CNTRC structures, which are strengthened by single-walled carbon nanotubes (SWCNTs), are scrutinized. The effectiveness of the present method is demonstrated by validating the obtained results against those of other studies from literature considering shell structures. Furthermore, some novel numerical results, including the nonlinear transient deflection of smart FG-CNTRC spherical and cylindrical shells, will be presented and can be considered for future structure design.

46 citations


Journal ArticleDOI
TL;DR: In this article, the recent advances in core/shell structured perovskite nanocrystals (NCs) are summarized and the prospective of these NCs in lighting and displays, solar cells, photodetectors, and other devices is discussed in the light of current knowledge, remaining challenges, and future opportunities.
Abstract: © 2021 Wiley-VCH GmbH Core/shell structured metal halide perovskite nanocrystals (NCs) are emerging as a type of material with remarkable optical and electronic properties. Research into this field has been developing and expanding rapidly in recent years, with significant advances in the studies of the shell growth mechanism and in understanding of properties of these materials. Significant enhancement of both the stability and the optical performance of core/shell perovskite NCs are of particular importance for their applications in optoelectronic technologies. In this review, the recent advances in core/shell structured perovskite NCs are summarized. The band structures and configurations of core/shell perovskite NCs are elaborated, the shell classification and shell engineering approaches, such as perovskites and their derivative shells, semiconductor shell, oxide shell, polymer shell, etc. are reviewed, and the shell growth mechanisms are discussed. The prospective of these NCs in lighting and displays, solar cells, photodetectors, and other devices is discussed in the light of current knowledge, remaining challenges, and future opportunities.

45 citations


Journal ArticleDOI
TL;DR: In this article, the vibrational behavior of composite coupled conical-conical shell structures is predicted by using a modified generalized differential quadrature method (GDQM) to solve the system of differential equations, an efficient and modified GDQM is employed.
Abstract: This article is dedicated to predict the vibrational behavior of composite coupled conical-conical shell structures. The structural material is composed of two phases, including polymer epoxy matrix and Carbon NanoTube (CNT) fibers. To improve the vibrational structural behavior, the distributions of CNTs throughout the thickness of shells are assumed to be Functionally Graded. In order to enhance the research, five different patterns are considered for distribution of the CNT fibers within the matrix. The governing equations of motion associated with conical shells are obtained by using Donnell's theory and Hamilton method. In addition, the five-parameter shell theory is utilized in this article. As a result, five differential equations are achieved by using variation calculation. To solve the system of differential equations, an efficient and modified Generalized Differential Quadrature Method (GDQM) is employed. All the natural frequencies of shell structures are found for different states. By considering continuity conditions, the required modification is applied to GDQM. To validate the proposed formulation, some well-known benchmarks are solved. Moreover, several numerical examples and parametric studies are implemented to show the high accuracy and capability of the authors' scheme for analyzing coupled shells. To obtain accurate responses, 15 grid points are required for using in GDQM. Besides, it is observed that the minimum and maximum dimensionless frequency parameters are obtained by the patterns F G − O and F G − X , respectively.

42 citations


Journal ArticleDOI
TL;DR: In this paper, a rotating functionally graded graphene nanoplatelets (GPLs) reinforced composite cylindrical shell with matrix cracks is analyzed using the modified Halpin-Tsai model and self-consistent model to determine the effective materials properties and stiffness degradation.
Abstract: Rotating cylindrical shells have been widely used in rotating machinery. The vibration characteristics of rotating composite cylindrical shells have a significant influence on the rotor dynamics. This paper provides a useful approach for the vibration analysis of a rotating functionally graded (FG) graphene nanoplatelets (GPLs) reinforced composite (GPLRC) cylindrical shell with matrix cracks. GPLs and matrix cracks are distributed in multilayer FG-GPLRC shells. The modified Halpin-Tsai model and self-consistent model are employed to determine the effective materials properties and stiffness degradation of the composite shell. The energy functional of rotating FG-GPLRC cylindrical shells are obtained using the first-order shear deformation theory (FSDT). Based on the improved moving least-squares Ritz (IMLS-Ritz) approximation, the discrete vibration equations of rotating FG-GPLRC cylindrical shells are derived. The accuracy of the IMLS-Ritz results is examined by comparing the natural frequencies with those presented in the previously published papers. Then the effects of crack density parameter, rotating speed, GPLs parameters, weight fraction, size and geometry, as well as the geometry of the cylindrical shell and boundary conditions on the critical rotating speed and natural frequency are examined comprehensively.

39 citations


Journal ArticleDOI
TL;DR: In this paper, the authors investigated the poroelasticity properties of functionally graded graphene platelets reinforced composite (FG-GPLRC) open-shells and found that the PF's frequency response is overestimated in comparison with 3D elasticity.

Journal ArticleDOI
TL;DR: In this paper, the nonlinear dynamic responses of a functionally graded (FG) porous cylindrical shell embedded in elastic media are investigated, and an approximate analytical solution is obtained by using the multiple scales method.
Abstract: In this article, the nonlinear dynamic responses of sandwich functionally graded (FG) porous cylindrical shell embedded in elastic media are investigated. The shell studied here consists of three layers, of which the outer and inner skins are made of solid metal, while the core is FG porous metal foam. Partial differential equations are derived by utilizing the improved Donnell’s nonlinear shell theory and Hamilton’s principle. Afterwards, the Galerkin method is used to transform the governing equations into nonlinear ordinary differential equations, and an approximate analytical solution is obtained by using the multiple scales method. The effects of various system parameters, specifically, the radial load, core thickness, foam type, foam coefficient, structure damping, and Winkler-Pasternak foundation parameters on nonlinear internal resonance of the sandwich FG porous thin shells are evaluated.

Journal ArticleDOI
TL;DR: In this paper, an analytical approach is proposed to investigate the nonlinear dynamic analysis of porous eccentrically stiffened (PES) double curved shallow auxetic shells with negative Poisson's ratio (NPR) subjected to blast, mechanical and thermal loads resting on Visco-Pasternak foundation model.
Abstract: In this paper, an analytical approach is proposed to investigate the nonlinear dynamic analysis of porous eccentrically stiffened (PES) double curved shallow auxetic shells with negative Poisson’s ratio (NPR) subjected to blast, mechanical and thermal loads resting on Visco-Pasternak foundation model. The three-layer double curved shallow shell consists of auxetic honeycombs core layer with NPR integrated, isotropic homogeneous materials at the top and bottom of surfaces. Besides, the outer surfaces of the system reinforced by PES are made of functionally graded materials (FGM) and auxetic shells are placed in thermal environments. Combining with the first-order shear deformation theory and Von-Karman strains, governing equations for nonlinear dynamic response of PES double curved shallow auxetic shells in thermal environments are derived. Then, the stress function and Galerkin methods are proposed to obtain the result equations: fundamental frequency, dynamic response, and frequency–amplitude relation. Compared with the published literature, the feasibility and accuracy of the proposed analysis approach are validated. Finally, the effects of stiffeners, Poisson’s ratio, cell inclined angle, mechanical, thermal and blast loads, elastic foundations, boundary conditions, geometrical parameters of auxetic honeycombs core and shell on the nonlinear dynamic response of PES double curved shallow auxetic shells in thermal environments are also carried out in the paper.

Journal ArticleDOI
TL;DR: In this article, a semi-analytical method is proposed to determine the acoustic power, radiation efficiency, source location and far-field acoustic pressure of annular acoustic black holes (ABHs) shells and compare them with those of uniform thickness shells.

Journal ArticleDOI
TL;DR: In this article, an innovative model is proposed, based on an equivalent single layer approach and higher order theories, for an accurate estimation of the vibrational response of plates, panels and shells, whose results are compared with predictions from a classical Finite Element Method (FEM).
Abstract: Anisotropic doubly-curved shells reinforced with a honeycomb core are innovative structures for applications in civil, biomedical, and aerospace engineering. In this context, the homogenization technique represents one of the simplest way for analyzing such complex structures. A proper formulation must be capable to give accurate results for any cell configuration and/or curved shape. In the present work an innovative model is proposed, based on an Equivalent Single Layer (ESL) approach and higher order theories, for an accurate estimation of the vibrational response of plates, panels and shells, whose results are compared with predictions from a classical Finite Element Method (FEM). The work starts with a comparative study performed on aluminum sandwich plates with hexagonal, rectangular and re-entrant cells. Then, a sensitivity analysis evaluates the dynamic response of single- and doubly-curved panels with different cell typologies. The fundamental equations are tackled numerically by resorting to the 2D Generalized Differential Quadrature (GDQ) method. The influence of the kinematic assumptions throughout the thickness on the dynamic response of shells is investigated, accounting for different Representative Volume Element (RVE) deformation effects within the homogenized model. In all the analyses, cell units are analyzed by means of different geometric angles, thin and thick cores, as well as classic and double thickness vertical walls or commercial honeycomb cores.

Journal ArticleDOI
TL;DR: In this article, the high-order partial differential equation (PDE) of thin cylindrical shells is derived from the Flugge shell theory, and the vibration response of the cylinear shell system is obtained by the wave propagation method.

Journal ArticleDOI
TL;DR: In this article, Biancolini's method was extended to include the possibility of determining, apart from the tensile and flexural stiffnesses, also the transverse shear stiffness of the homogenized corrugated board.
Abstract: Knowing the material properties of individual layers of the corrugated plate structures and the geometry of its cross-section, the effective material parameters of the equivalent plate can be calculated. This can be problematic, especially if the transverse shear stiffness is also necessary for the correct description of the equivalent plate performance. In this work, the method proposed by Biancolini is extended to include the possibility of determining, apart from the tensile and flexural stiffnesses, also the transverse shear stiffness of the homogenized corrugated board. The method is based on the strain energy equivalence between the full numerical 3D model of the corrugated board and its Reissner-Mindlin flat plate representation. Shell finite elements were used in this study to accurately reflect the geometry of the corrugated board. In the method presented here, the finite element method is only used to compose the initial global stiffness matrix, which is then condensed and directly used in the homogenization procedure. The stability of the proposed method was tested for different variants of the selected representative volume elements. The obtained results are consistent with other technique already presented in the literature.

Journal ArticleDOI
TL;DR: In this article, the authors proposed new quadrature schemes that asymptotically require only four in-plane points for Reissner-Mindlin shell elements and nine in plane points for Kirchhoff-Love shell elements in B-spline and NURBS-based isogeometric shell analysis, independent of the polynomial degree of the elements.

Journal ArticleDOI
TL;DR: In this article, the authors investigated the absorbed energy and dynamic stability analysis of the FG-CNTRC curved panel surrounded by a non-polynomial viscoelastic substrate using three-dimensional poroelasticity theory.

Journal ArticleDOI
01 Sep 2021-Optik
TL;DR: In this article, the nanostructured materials from Ag and Au@Ag core/shell bimetallic were synthesized by pulsed infrared laser ablation process in different liquid media technique in just one-pot step.

Journal ArticleDOI
TL;DR: In this paper, a novel unconstrained higher-order theory (UCHOT) is applied to analyse the free vibration of cylindrical sandwich shells with nanocomposite face sheets reinforced with graphene platelets.


Journal ArticleDOI
TL;DR: In this paper, a set of shape functions for cylindrical shell structures is created for polynomial expansion and data consistency assessment and modification, which can assess the consistency of the data set and identify the inconsistent points.

Journal ArticleDOI
TL;DR: In this article, the resonance phenomenon in anisotropic and functionally graded nano-size structure is investigated in a doubly curved shell which is modeled exploiting a quasi-three-dimensional model and nonlocal strain gradient theory in order to predict the small-size effects.

Journal ArticleDOI
TL;DR: In this article, an analytical strategy is proposed to determine the vibration response of a doubly curved composite shell in a thermal environment, where the main aim is to show the effect of thermal loads on sound transmission loss (STL).

Journal ArticleDOI
TL;DR: In this article, an analytic dynamic stiffness method (DSM) is extended to analyze the free and forced vibration of combined conical-cylindrical shells with general boundary conditions.
Abstract: An analytic dynamic stiffness method (DSM) is extended to analyze the free and forced vibration of combined conical-cylindrical shells with general boundary conditions in this paper. Flugge shell theory is utilized to formulate the motion equations of each shell component. Based on the exact general solutions of the motion equations, the dynamic stiffness matrices for each shell segment are established separately and the global dynamic stiffness matrix for the whole structure is established by assembling the dynamic stiffness matrices for each shell segment similarly as finite element method (FEM) did. Natural frequencies and forced responses of the combined shells are obtained based on the global dynamic stiffness matrix. Through comparing vibration results of DSM with ones from open literature and FEM, rapid convergence, good accuracy, and high efficiency of the DSM are demonstrated. In the numerical examples, the influences of boundary conditions, axial and circumferential mode numbers, and semi-vertex angles on the free vibration are studied. The effects of direction and location of external force and structural damping on the forced vibration are also discussed.

Journal ArticleDOI
TL;DR: In this paper, a parallel computational method for simulating fluid-structure interaction problems involving large, geometrically nonlinear deformations of thin shell structures is presented and validated.

Journal ArticleDOI
TL;DR: In this paper, the free vibrations of graphene platelet reinforced composite (GPLRC) cylindrical shells were investigated using the first-order shear deformation theory of shells and the Donnell kinematic relations.

Journal ArticleDOI
TL;DR: In this paper, a comparison between two different computational techniques to evaluate the natural frequencies of some selected structural components is proposed, i.e., the 1D-Hierarchical Ritz Formulation (HRF) with 3D capabilities and the 2D-Generalized Differential Quadrature (GDQ) formulation (both in a weak-and a strong-form) are assessed by using a Finite Element Method of Power Series Expansion of the Displacement Components (MPSEDCs) software.

Journal ArticleDOI
TL;DR: In this article, the mechanical behavior of the micro Schwarz Primitive triply periodic minimal surfaces (P-TPMS) cylinder shell structures fabricated with projection micro-stereolithography (PμSL) 3D printing technique were investigated.