Approximate formulation for bifurcation buckling loads of axially compressed cylindrical shells with an elastic core

2011 ◽  
Vol 4 (4) ◽  
pp. 313-320
Author(s):  
Motohiro Sato ◽  
Kenta Shimazaki
Author(s):  
Haigui Fan ◽  
Wenguang Gu ◽  
Longhua Li ◽  
Peiqi Liu ◽  
Dapeng Hu

Buckling design of axially compressed cylindrical shells is still a challenging subject considering the high imperfection-sensitive characteristic in this kind of structure. With the development of various design methods, the energy barrier concept dealing with buckling of imperfection-sensitive cylindrical shells exhibits a promising prospect in recent years. In this study, buckling design of imperfection-sensitive cylindrical shells under axial compression based on the energy barrier approach is systematically investigated. The methodology about buckling design based on the energy barrier approach is described in detail first taking advantage of the cylindrical shells whose buckling loads have been extensively tested. Then, validation and discussion about this buckling design method have been carried out by the numerical and experimental analyses on the cylindrical shells with different geometrical and boundary imperfections. Results in this study together with the available experimental data have verified the reliability and advantage of the buckling design method based on energy barrier approach. A design criterion based on the energy barrier approach is therefore established and compared with the other criteria. Results indicate that buckling design based on energy barrier approach can be used as an efficient way in the lightweight design of thin-shell structures.


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.


2018 ◽  
Vol 21 (16) ◽  
pp. 2454-2465
Author(s):  
Cornelia Doerich ◽  
Margi Vilnay ◽  
J Michael Rotter

Cylindrical shells are often subjected to local inward loads normal to the shell that arise over restricted zones. A simple axisymmetric example is that of the ring-loaded cylinder, in which an inward line load around the circumference causes either plasticity or buckling. The ring-loaded cylinder problem is highly relevant to shell junctions in silos, tanks and similar assemblies of shell segments. The band load is similar to the ring load in which a band of inward axisymmetric pressure is applied over a finite height. When the height is very small, the situation approaches the ring-loaded case, and when the height is very large, it approaches the uniformly pressurised case. This article first thoroughly explores the two limiting cases of plastic collapse and linear bifurcation buckling, which must both be fully defined before a complete description of the nonlinear and imperfection-sensitive strengths of such shells can be described within the framework of the European standard for shells (EN 1993-1-6). Finally, the application of the reference resistance design (RRD) over the complete range of geometries for the perfect structure is shown using the outcome of the limiting cases.


1993 ◽  
Vol 115 (3) ◽  
pp. 268-274 ◽  
Author(s):  
N. Miyazaki ◽  
S. Hagihara

In the present work, analytical and experimental investigations were performed on creep buckling. Special attention was focussed on bifurcation behavior during creep deformation. The finite element method was used to analyze creep buckling of circular cylindrical shells without initial imperfection. The number of circumferential waves obtained from the analyses agrees well with those of the experiments. The present experimental investigation shows that the circumferential waves are suddenly caused near a bulge. It is also found that there is no correlation between the wavelength of the circumferential waves observed at creep buckling and that of the circumferential initial imperfection. Deformation patterns at the bifurcation creep buckling obtained from the analyses are analogous to those of the experiments. It is concluded from the analyses and the experiments that the circumferential waves observed in creep buckling experiments are due to bifurcation buckling during creep deformation.


2013 ◽  
Vol 135 (5) ◽  
Author(s):  
Xinsheng Xu ◽  
Jiabin Sun ◽  
C. W. Lim

This study is mainly concerned with the analytical solutions of plastic bifurcation buckling of cylindrical shells under compressive load. The analysis is based on the J2 deformation theory with a linear hardening and proportional loading is adopted in the calculation. A symplectic solution system is established and Hamilton's governing equations are derived from the Hamilton variational principle. The basic problem in plastic buckling is converted into solving for the symplectic eigenvalues and eigensolutions, respectively. The obtained results reveal that boundary conditions have a very limited influence on bucking loads but its influence on buckling modes and plastic borders cannot be neglected. Meanwhile, it is demonstrated that the shell material properties significantly affect the plastic buckling behavior. This proposed symplectic method is shown to be a rigorous approach. It also provides a uniform and systematic way to any other similar problems.


2011 ◽  
Vol 110-116 ◽  
pp. 1773-1783
Author(s):  
Jia Mao ◽  
Yu Feng Chen ◽  
Wei Hua Zhang

Parametric structural FEA (Finite Element Analysis) models of the orthogonal rib-stiffened thin walled cylindrical shells are established using APDL (ANSYS Parametric Design Language). An experiential optimization design method is then developed based on conclusions of series numerical analysis investigating the effects of parameters’ modification upon buckling loads and modes of the structure. The effects of single design parameter modification under both variational and fixed volume (mass) constraints upon the buckling loads and modes indicate that, only one design scheme is able to obtain maximum buckling load when deployment of the strengthening ribs and volume (mass) parameter were settled previously, and minimum mass would be obtained while this maximum buckling load equals to the required design load. Optimization calculations for aluminum alloy material and layered C/E (Carbon/Epoxy) composite material shells with three layering styles are implemented and discussed, and some useful conclusions are obtained. Method and approach developed in this paper provide certain reference value for the optimal design of such structures.


Author(s):  
P Khazaeinejad ◽  
M M Najafizadeh

The analytical solutions of the first-order shear deformation theory are developed to study the buckling behaviour of functionally graded (FG) cylindrical shells under three types of mechanical loads. The Poisson's ratios of the FG cylindrical shells are assumed to be constant, while the Young's moduli vary continuously throughout the thickness direction according to the volume fraction of constituents given by power-law or exponential function. The stability equations are employed to obtain the closed-form solutions for critical buckling loads of each loading case. The dependence of the critical buckling loads on the variations of the material properties with a power-law or exponential function is studied. It is observed that these effects change appreciably the critical buckling loads. Results for critical loads are tabulated for thin and moderately thick shells. Although the critical buckling load of FG cylindrical shells decreases as the circumferential wave numbers increase, it rises for axially compressed long shells as the longitudinal wave numbers increase.


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