Collapse of Thin Orthotropic Elliptical Cylindrical Shells Under Combined Bending and Pressure Loads

1979 ◽  
Vol 46 (2) ◽  
pp. 363-371 ◽  
Author(s):  
J. Spence ◽  
S. L. Toh
Keyword(s):  
Shell Theory ◽  
Nonlinear Boundary ◽  
Cylindrical Shells ◽  
Normal Pressure ◽  
Nonlinear Ordinary Differential Equations ◽  
Pure Bending ◽  
Finite Deflection ◽  
Shooting Technique ◽  
Theoretical Predictions ◽  
Thin Shell Theory

The elastic collapse of thin orthotropic elliptical cylindrical shells subject to pure bending alone or combined bending and uniform normal pressure loads has been studied. Nonlinear finite deflection thin shell theory is employed and this reduces the problem to a set of nonlinear ordinary differential equations. The resulting two-point nonlinear boundary-value problem is then linearized, using quasi-linearization, and solved numerically by the “shooting technique.” Some experimental work has been carried out and the results are compared with the theoretical predictions.

Acoustic and Vibration Characteristics of Stiffened Finite Cylindrical Shells in Water under Multiple Axial-Excitations

2013 ◽  
Vol 662 ◽  
pp. 721-725
Author(s):  
Qi Zheng Zhou ◽  
De Shi Wang ◽  
Sheng Yao Gao
Keyword(s):  
Analytical Solution ◽  
Shell Theory ◽  
Acoustic Pressure ◽  
Acoustic Radiation ◽  
Cylindrical Shells ◽  
High Frequencies ◽  
Acoustic Coupling ◽  
Coupling Equations ◽  
Vibration And Sound Radiation ◽  
Thin Shell Theory

A research on the vibration and acoustic radiation of stiffened finite cylindrical shells in water under a multiple axial-excitations driven was presented. The vibro-acoustic coupling equations of shell under multiple axial-excitations based on Flügge thin shell theory were established. The displacements, surface acoustic pressure and stiffener impedances were expressed in terms of the numbers of normal modals and modes, and considering multiple excitations, the forces were expressed in terms of the numbers of normal modals and modes. Then analytical solution was derived for the vibration and sound radiation from the stiffened shell under multiple excitations. Based on the analytical solution, the influences of excitations’ positions to the vibration and acoustic radiation were investigated. The results show that for double excitations, at high frequencies, the distance between excitations was more large, the average velocity was more low. The results could be used to control the underwater vehicle’s vibration and acoustic radiation.

scholarly journals Prediction of Vibrational Behavior of Grid-Stiffened Cylindrical Shells

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
G. H. Rahimi ◽  
M. Hemmatnezhad ◽  
R. Ansari
Keyword(s):  
Shell Theory ◽  
Cylindrical Shells ◽  
Element Model ◽  
Geometrical Parameters ◽  
Equivalent Stiffness ◽  
Theoretical Formulation ◽  
Vibrational Behavior ◽  
Thin Shell Theory ◽  
Stiffened Cylindrical Shells ◽  
Good Agreement

A unified analytical approach is applied to investigate the vibrational behavior of grid-stiffened cylindrical shells with different boundary conditions. A smeared method is employed to superimpose the stiffness contribution of the stiffeners with those of shell in order to obtain the equivalent stiffness parameters of the whole panel. Theoretical formulation is established based on Sanders’ thin shell theory. The modal forms are assumed to have the axial dependency in the form of Fourier series whose derivatives are legitimized using Stoke's transformation. A 3D finite element model is also built using ABAQUS software which takes into consideration the exact geometric configuration of the stiffeners and the shell. The achievements from the two types of analyses are compared with each other and good agreement has been obtained. The Influences of variations in shell geometrical parameters, boundary condition, and changes in the cross stiffeners angle on the natural frequencies are studied. The results obtained are novel and can be used as a benchmark for further studies. The simplicity and the capability of the present method are also discussed.

Vibration tests on spherical shell caps

1983 ◽  
Vol 18 (1) ◽  
pp. 27-36 ◽  
Author(s):  
V C M De Souza ◽  
J G A Croll
Keyword(s):  
Spherical Shell ◽  
Shell Thickness ◽  
Shell Theory ◽  
Small Scale ◽  
Modal Interactions ◽  
Excitation Energies ◽  
Theoretical Predictions ◽  
Low Levels ◽  
Vibration Tests ◽  
Thin Shell Theory

Fabrication and testing of vibrations in small-scale, electroplated nickel, spherical shell caps which are clamped on their open boundaries, are briefly described. Comparisons with theoretical predictions show that with low levels of excitation energy, for which displacements in the resonant response are considerably less than the shell thickness, classical thin shell theory provides a close description of observed resonance in both axisymmetric and non-axisymmetric modes. For larger excitation energies, for which resonant displacements are of the same order as the shell thickness, tests are reported to show the possible need to include in analysis the effects of geometric non-linear, modal interactions.

Laminated Transversely Isotropic Cylindrical Shells

1971 ◽  
Vol 38 (2) ◽  
pp. 400-407 ◽  
Author(s):  
J. A. Zukas ◽  
J. R. Vinson
Keyword(s):  
Shell Theory ◽  
Transverse Isotropy ◽  
Cylindrical Shells ◽  
Pyrolytic Graphite ◽  
Transversely Isotropic ◽  
Sample Problem ◽  
Governing Equations ◽  
Slow Cooling ◽  
Circular Cylindrical Shells ◽  
Thin Shell Theory

A theory for the analysis of stresses in laminated circular cylindrical shells subjected to arbitrary axisymmetric mechanical and thermal loadings has been developed. This theory, specifically for use with pyrolytic-graphite-type materials, differs from the classical thin shell theory in that it includes the effects of transverse shear deformation and transverse isotropy, as well as thermal expansion through the shell thickness. Solutions in several forms are developed for the governing equations. The form taken by the solution function is governed by geometric considerations. A range in which the various solution forms occur was determined numerically. As a sample problem, the slow cooling of pyrolytic graphite deposited onto a commercial graphite mandrel was considered. Investigation of normal and shear stress behavior at the pyrolytic graphite-mandrel interface showed that these stresses decrease in magnitude with increasing E/Gc ratio and increasing deposit to mandrel thickness (ha/hb) ratio. This implies that a thin mandrel and a material weak in shear are desirable to minimize the possibilities of flaking and delamination of the pyrolytic graphite.

Non-Axisymmetric Vibrations of Stepped Cylindrical Shells Containing Cracks

2014 ◽  
Vol 934 ◽  
pp. 136-142
Author(s):  
Larissa Roots
Keyword(s):  
Shell Theory ◽  
Natural Frequencies ◽  
Cylindrical Shells ◽  
Axisymmetric Vibration ◽  
Approximate Evaluation ◽  
Linear Fracture ◽  
Local Flexibility ◽  
Circular Cylindrical Shells ◽  
Thickness Variations ◽  
Thin Shell Theory

Based on the Donnell’s approximations of the thin shell theory, this paper presents solutions for the problem of free non-axisymmetric vibration of stepped circular cylindrical shells with cracks. The shell under consideration is sub-divided into multiple segments separated by the locations of thickness variations. It is assumed that at thejth step there exists a circumferential surface crack with uniform depthcj. The influence of circular cracks with constant depth on the vibration of the shell is prescribed with the aid of a matrix of local flexibility. The latter is related to the coefficient of the stress intensity known in the linear fracture mechanics. Numerical results are obtained for cylindrical shells of stepped thickness containing cracks at re-entrant corners of steps. Shells with various combinations of boundary conditions can be analyzed by the proposed method. Furthermore, the influences of the shell thicknesses, locations of step-wise variations of the thickness and other parameters on the natural frequencies are examined. The results can be used for the approximate evaluation of dynamic parameters of cylindrical shells with cracks and flaws.

Dynamic Thermoelastic Response of Cylindrical Shells

1970 ◽  
Vol 37 (3) ◽  
pp. 661-670 ◽  
Author(s):  
E. J. McQuillen ◽  
M. A. Brull
Keyword(s):  
Shell Theory ◽  
Cylindrical Shells ◽  
Infinite Length ◽  
Dynamic Effects ◽  
Thermoelastic Response ◽  
Shell Equations ◽  
Thermoelastic Problems ◽  
Thin Shell Theory ◽  
Fully Coupled ◽  
Coupled Theory

The dynamic, thermoelastic response of cylindrical shells to suddenly applied and rotating thermal inputs is investigated. Fully coupled, dynamic, thermoelastic cylindrical shell equations are derived using Galerkin’s method. Identical results were obtained independently using a variational theorem. Analytical solutions to these equations are formulated for finite-length and infinite-length cylinders. Numerical results for the response of infinite-length cylindrical shells to suddenly applied and rotating longitudinal lines of heat flux are presented. It is shown that for many thermoelastic problems involving moving thermal inputs that the maximum ratio of dynamic to quasi-static deflection can be much greater than two, that dynamic effects can be important for all thicknesses within the realm of thin shell theory, and that semicoupled theory gives incorrect results in some cases for which a fully coupled theory is required.

Elasto-Plastic Response of Pipes Under External Pressure and Bending

1988 ◽  
Vol 110 (2) ◽  
pp. 148-153
Author(s):  
C. J. Tay ◽  
S. L. Toh
Keyword(s):  
Work Hardening ◽  
Thin Shell ◽  
Shell Theory ◽  
Bending Moment ◽  
External Pressure ◽  
Plastic Behavior ◽  
Plastic Response ◽  
Finite Deflection ◽  
Hardening Material ◽  
Thin Shell Theory

The collapse of thin cylindrical pipes subject to combined bending moment and external pressure has been studied. Nonlinear finite deflection thin shell theory is employed in the elastic solution. The analysis is extended to include the plastic behavior with the assumption of linear work-hardening material. Results are presented for various geometric material and load configurations.

Investigation on Electrothermoelastic Behavior of FGPM Cylindrical Shells

2016 ◽  
Vol 17 (1) ◽  
Author(s):  
Hong-Liang Dai ◽  
Yi-Nan Qi ◽  
Wei-Feng Luo
Keyword(s):  
Cylindrical Shell ◽  
Analytical Solution ◽  
Shell Theory ◽  
Thermal Environment ◽  
Piezoelectric Materials ◽  
Cylindrical Shells ◽  
Functionally Graded ◽  
Sensory Structures ◽  
Functionally Graded Piezoelectric ◽  
Thin Shell Theory

AbstractThis paper presents an analytical solution for electrothermoelastic behavior of FGPM (functionally graded piezoelectric material) cylindrical shell. The cylindrical shell is assumed to be made up of two piezoelectric materials with their volume fractures varying along the thickness according to a simple power law. Based on classical thin shell theory, an analytical solution for electrothermoelastic performance of the FGPM cylindrical shell is presented. To investigate the influence of the power lower exponent, thermal environment, mechanical loading and electric boundary conditions on the electrothermoelastic behavior of FGPM cylindrical shells, numerical examples are presented and discussed, and some meaningful and valuable results are discovered, which will be very helpful for the design and application of such smart sensory structures.

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