Investigation of axisymmetric electroacoustic waves in a cylindrical sandwich shell by three-dimensional and applied theories

1987 ◽  
Vol 23 (10) ◽  
pp. 1005-1011
Author(s):  
N. A. Shul'ga ◽  
S. I. Rudnitskii ◽  
Yu. B. Evseichik
Keyword(s):  
Three Dimensional ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell

scholarly journals Vibration analysis of a sandwich cylindrical shell in hygrothermal environment

2021 ◽  
Vol 10 (1) ◽  
pp. 414-430
Author(s):  
Chunwei Zhang ◽  
Qiao Jin ◽  
Yansheng Song ◽  
Jingli Wang ◽  
Li Sun ◽  
...  
Keyword(s):  
Cylindrical Shell ◽  
Natural Frequency ◽  
Equations Of Motion ◽  
Single Layer ◽  
Functionally Graded ◽  
Sandwich Shell ◽  
Continuous Change ◽  
Multilayered Structures ◽  
Cylindrical Sandwich Shell ◽  
Vibrational Behavior

Abstract The sandwich structures are three- or multilayered structures such that their mechanical properties are better than each single layer. In the current research, a three-layered cylindrical shell including a functionally graded porous core and two reinforced nanocomposite face sheets resting on the Pasternak foundation is used as model to provide a comprehensive understanding of vibrational behavior of such structures. The core is made of limestone, while the epoxy is utilized as the top and bottom layers’ matrix phase and also it is reinforced by the graphene nanoplatelets (GNPs). The pattern of the GNPs dispersion and the pores distribution play a crucial role at the continuous change of the layers’ properties. The sinusoidal shear deformation shells theory and the Hamilton’s principle are employed to derive the equations of motion for the mentioned cylindrical sandwich shell. Ultimately, the impacts of the model’s geometry, foundation moduli, mode number, and deviatory radius on the vibrational behavior are investigated and discussed. It is revealed that the natural frequency and rotation angle of the sandwich shell are directly related. Moreover, mid-radius to thickness ratio enhancement results in the natural frequency reduction. The results of this study can be helpful for the future investigations in such a broad context. Furthermore, for the pipe factories current study can be effective at their designing procedure.

Buckling of a Circular Cylindrical Web-Stiffened Sandwich Shell Under Axial Compression

1974 ◽  
Vol 18 (01) ◽  
pp. 55-61
Author(s):  
Vincent Volpe ◽  
Youl-Nan Chen ◽  
Joseph Kempner
Keyword(s):  
Axial Compression ◽  
Large Deflection ◽  
Single Layer ◽  
Subsequent Development ◽  
Buckling Load ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell ◽  
Axisymmetric Mode ◽  
Shell Equations ◽  
The Mathematical Model

A stability analysis of an infinitely long web-stiffened, circular cylindrical sandwich shell under uniform axial compression is presented. The formulation begins with the establishment of a set of suitable large-deflection shell equations that forms the basis for the subsequent development of the buckling equations. The mathematical model corresponds to two face layers that are considered as thin shells and a thick core that is capable of resisting both transverse shear and circumferential extension. The associated eigenvalue problem is solved. Results show that the lowest buckling load is associated with the axisymmetric mode and is less than one half the buckling load of an equivalent single-layer shell.

Flexure of a cylindrical sandwich shell of variable thickness

1968 ◽  
Vol 4 (5) ◽  
pp. 36-39
Author(s):  
I. M. Pirogov ◽  
F. I. Selitskii
Keyword(s):  
Variable Thickness ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell

Strength Analysis of Sandwich Shell Structures Subjected to Hydrostatic Load

1993 ◽  
Vol 37 (03) ◽  
pp. 253-272
Author(s):  
W. Cho ◽  
N. A. Papadakis
Keyword(s):  
Hydrostatic Pressure ◽  
Static Analysis ◽  
Numerical Results ◽  
Shell Structures ◽  
Strength Analysis ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell ◽  
The Core ◽  
Hydrostatic Load ◽  
Alternative Designs

The strength of a circular, cylindrical sandwich shell subjected to hydrostatic pressure is examined. An energy methodology appropriate for static analysis of sandwich shells is presented. Interactions of the inner and outer shell with the core stiffeners interconnecting these shells are investigated. Numerical results are discussed, together with comparisons between the sandwich shell and alternative designs.

On the Optimum Design of Shells

1960 ◽  
Vol 27 (2) ◽  
pp. 316-322 ◽  
Author(s):  
R. T. Shield
Keyword(s):  
Optimum Design ◽  
Plastic Shell ◽  
Minimum Volume ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell ◽  
Design Effect ◽  
Perfectly Plastic ◽  
Body Forces ◽  
Membrane Design ◽  
Elastic Perfectly Plastic

A procedure is developed for obtaining the design of an elastic, perfectly plastic shell or structure which will support prescribed loads and which is the optimum design for a given criterion. The action of body forces is included in the analysis. Some problems in the minimum volume design of a circular cylindrical sandwich shell are solved to illustrate the method, and it is found that only for relatively short shells does the minimum volume design effect an appreciable saving over the membrane design.

Optimal Damping in Circular Cylindrical Sandwich Shells With a Three-Layered Viscoelastic Composite Core

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Ambesh Kumar ◽  
Satyajit Panda
Keyword(s):  
Composite Layer ◽  
Middle Surface ◽  
Layered Composite ◽  
Fe Model ◽  
Sandwich Shell ◽  
Cylindrical Sandwich Shell ◽  
Viscoelastic Composite ◽  
Damping Characteristics ◽  
Viscoelastic Core ◽  
Viscoelastic Layers

In this work, the damping characteristics of circular cylindrical sandwich shell with a three-layered viscoelastic composite core are investigated. The new composite core is composed of the identical inclusions of graphite-strips which are axially embedded within a cylindrical viscoelastic core at its middle surface. The physical configuration of the composite core is attributed in the form of a cylindrical laminate of two identical monolithic viscoelastic layers over the inner and outer cylindrical surfaces of middle viscoelastic composite layer so that it is a three-layered viscoelastic composite core. A finite element (FE) model of the overall shell is developed based on the layerwise deformation theory and Sander's shell theory. Using this FE model, the damping characteristics of the shell are studied within an operating frequency range after configuring the size and circumferential distribution of graphite-strips in optimal manner. The numerical results reveal significantly improved damping in the sandwich shell for the use of present three-layered composite core instead of traditional single-layered viscoelastic core. It is also found that the three-layered core provides the advantage in achieving damping at different natural modes as per their assigned relative importance while it is impossible in the use of single-layered viscoelastic core.

scholarly journals Vibrations of a Cylindrical Sandwich Shell with a Honeycomb Core Made Using FDM technology

2021 ◽  
Vol 24 (4) ◽  
pp. 49-60
Author(s):  
Borys V. Uspenskyi ◽  
◽  
Kostiantyn V. Avramov ◽  
Ihor I. Derevianko ◽  
◽  
...  
Keyword(s):  
Fused Deposition Modeling ◽  
Ritz Method ◽  
Order Theory ◽  
Circumferential Direction ◽  
Sandwich Shell ◽  
Honeycomb Core ◽  
Transverse Coordinate ◽  
Cylindrical Sandwich Shell ◽  
Fused Deposition ◽  
Linear Vibrations

Presented is a model of the dynamic deformation of a three-layer cylindrical shell with a honeycomb core, manufactured by fused deposition modeling (FDM), and skins reinforced with oriented carbon nano-tubes (CNT). A ULTEM 9085 thermoplastic-based honeycomb core is considered. To analyze the stress-strain state of the honeycomb core, a finite element homogenization procedure was used. As a result of this procedure, the dynamic response of the honeycomb core is modeled by a homogeneous orthotropic material, whose mechanical properties correspond to those of the core. The proposed model is based on the high-order theory, extended for the analysis of sandwich structures. The skin displacement projections are expanded along the transverse coordinate up to quadratic terms. The honeycomb core displacement projections are expanded along the transverse coordinate up to cubic terms. To ensure the integrity of the structure, shell displacement continuity conditions at the junction of the layers are used. The investigation of linear vibrations of the shell is carried out using the Rayleigh-Ritz method. For its application, the potential and kinetic energies of the structure are derived. Considered are the natural frequencies and modes of vibrations of a one-side clamped cylindrical sandwich shell. The dependence of the forms and frequencies of vibrations on the honeycomb core thickness and the direction of reinforcement of the shell skins have been investigated. It was found that the eigenforms of a sandwich shell are characterized by a smaller number of waves in the circumferential direction, as well as a much earlier appearance of axisymmetric forms. This means that when analyzing the resonant vibrations of a sandwich shell, it is necessary to take into account axisymmetric shapes. Changing the direction of reinforcement of the skins with CNTs makes it possible to significantly influence the frequencies of the natural vibrations of the shell, which are characterized by a nonzero number of waves in the circumferential direction. It was found that this parameter does not affect the frequencies of the axisymmetric shapes of the shell under consideration.

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