Simplified Methods for Calculation of Redundant Moments and Forces at the Discontinuities in Pressure Vessels—Part II: Hemisphere—Shell and Shells of Different Thicknesses

1994 ◽  
Vol 116 (2) ◽  
pp. 204-206 ◽  
Author(s):  
H. Chen ◽  
K. Zhou

Following a similar idea as described in Part I of this paper, the redundant bending moment and the redundant shearing force at the junctures of hemispherical/cylindrical shells and of cylindrical shells of different thicknesses are shown to be unique functions of λ (ratio of the thickness of the joint members) and η (ratio of the thickness of the cylindrical shell to its mean diameter). Thereby, simplification of the calculation for the redundant moment and the redundant force is proposed and demonstrated to possess a good accuracy.

1969 ◽  
Vol 91 (3) ◽  
pp. 563-572 ◽  
Author(s):  
J. W. Hansberry ◽  
N. Jones

A theoretical study has been made into the elastic behavior of a joint formed by the normal intersection of a right circular cylindrical shell with another of larger diameter. The wall of the larger cylinder is assumed to remain open inside the joint in order to give an arrangement which is encountered frequently in pressure vessels or pipeline intersections. An external bending moment which acts in the plane of the joint is applied to the nozzle cylinder and is equilibriated by moments of half this magnitude applied to either end of the parent cylinder. A solution for this loading has been obtained by assuming antisymmetric distributions of certain stresses across a plane transverse to the joint. The analysis presented is believed to be valid for nozzle to cylinder diameter ratios of less than 1:3. Numerical results are given for a number of cases having radius ratios of 1:10 and 1:4.


2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Xiongtao Cao ◽  
Chao Ma ◽  
Hongxing Hua

A general method for predicting acoustic radiation from multiple periodic structures is presented and a numerical solution is proposed to find the radial displacement of thick laminated cylindrical shells with sparse cross stiffeners in the wavenumber domain. Although this method aims at the sound radiation from a single stiffened cylindrical shell, it can be easily adapted to analyze the vibrational and sound characteristics of two concentric cylindrical shells or two parallel plates with complicated periodic stiffeners, such as submarine and ship hulls. The sparse cross stiffeners are composed of two sets of parallel rings and one set of longitudinal stringers. The acoustic power of large cylindrical shells above the ring frequency is derived in the wavenumber domain on the basis of the fact that sound power is focused on the acoustic ellipse. It transpires that a great many band gaps of wave propagation in the helical wave spectra of the radial displacement for stiffened cylindrical shells are generated by the rings and stringers. The acoustic power and input power of stiffened antisymmetric laminated cylindrical shells are computed and compared. The acoustic energy conversion efficiency of the cylindrical shells is less than 10%. The axial and circumferential point forces can also produce distinct acoustic power. The radial displacement patterns of the antisymmetric cylindrical shell with fluid loadings are illustrated in the space domain. This study would help to better understand the main mechanism of acoustic radiation from stiffened laminated composite shells, which has not been adequately addressed in its companion paper (Cao et al., 2012, “Acoustic Radiation From Shear Deformable Stiffened Laminated Cylindrical Shells,” J. Sound Vib., 331(3), pp. 651-670).


2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Christopher Gilles Doherty ◽  
Steve C. Southward ◽  
Andrew J. Hull

Reinforced cylindrical shells are used in numerous industries; common examples include undersea vehicles, aircraft, and industrial piping. Current models typically incorporate approximation theories to determine shell behavior, which are limited by both thickness and frequency. In addition, many applications feature coatings on the shell interior or exterior that normally have thicknesses which must also be considered. To increase the fidelity of such systems, this work develops an analytic model of an elastic cylindrical shell featuring periodically spaced ring stiffeners with a coating applied to the outer surface. There is an external fluid environment. Beginning with the equations of elasticity for a solid, spatial-domain displacement field solutions are developed incorporating unknown wave propagation coefficients. These fields are used to determine stresses at the boundaries of the shell and coating, which are then coupled with stresses from the stiffeners and fluid. The stress boundary conditions contain double-index infinite summations, which are decoupled, truncated, and recombined into a global matrix equation. The solution to this global equation results in the displacement responses of the system as well as the exterior scattered pressure field. An incident acoustic wave excitation is considered. Thin-shell reference models are used for validation, and the predicted system response to an example simulation is examined. It is shown that the reinforcing ribs and coating add significant complexity to the overall cylindrical shell model; however, the proposed approach enables the study of structural and acoustic responses of the coupled system.


Author(s):  
S. Harutyunyan ◽  
D. J. Hasanyan ◽  
R. B. Davis

Formulation is derived for buckling of the circular cylindrical shell with multiple orthotropic layers and eccentric stiffeners acting under axial compression, lateral pressure, and/or combinations thereof, based on Sanders-Koiter theory. Buckling loads of circular cylindrical laminated composite shells are obtained using Sanders-Koiter, Love, and Donnell shell theories. These theories are compared for the variations in the stiffened cylindrical shells. To further demonstrate the shell theories for buckling load, the following particular case has been discussed: Cross-Ply with N odd (symmetric) laminated orthotropic layers. For certain cases the analytical buckling loads formula is derived for the stiffened isotropic cylindrical shell, when the ratio of the principal lamina stiffness is F = E2/E1 = 1. Due to the variations in geometrical and physical parameters in theory, meaningful general results are complicated to present. Accordingly, specific numerical examples are given to illustrate application of the proposed theory and derived analytical formulas for the buckling loads. The results derived herein are then compared to similar published work.


1969 ◽  
Vol 4 (1) ◽  
pp. 57-64
Author(s):  
R W T Preater

Three different assumptions are made for the behaviour of the junction between the cylindrical shell and the end closure. Comparisons of analytical and experimental results show that the inclusion of a ‘rigid’ annular ring beam at the junction of the cylider and the closure best represents the shell behaviour for a ratio of cylinder mean radius to thickness of 3–7, and enables a prediction of an optimum vessel configuration to be made. Experimental verification of this optimum design confirms the predictions. (The special use of the term ‘rigid’ is taken in this context to refer to a ring beam for which deformations of the cross-section are ignored but rigid body motion is permitted.)


2006 ◽  
Vol 324-325 ◽  
pp. 523-526 ◽  
Author(s):  
Gang Chen ◽  
Qing Ping Zhang ◽  
Zhong Fu Chen ◽  
Si Zhong Li ◽  
Yu Ze Chen

Cylindrical shell is a kind of common used structure in engineering. Interest in the response of cylindrical shells to local impact loading has increased over the last few years. A structure always endures working load more or less. For a cylindrical shell, the working load commonly is internally pressure. In this paper, a numeral simulation of wedge block impact internally Pressured cylindrical shell was carried out. The dynamic failure process of the structure was obtained. The consistency between experimental observation and numerical simulation is satisfactory.


1955 ◽  
Vol 22 (1) ◽  
pp. 111-116
Author(s):  
E. H. Kennard

Abstract The strain energy in a homogeneous cylindrical shell of uniform thickness is calculated from equations obtained by Epstein’s method. The indeterminateness of the equations of equilibrium is further discussed and simplified forms of these equations and of the expressions for the stress resultants are given. Addenda and an erratum to a prior paper are included.


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