Comparative Study Concerning the Methods of Calculation of the Critical Axial Buckling Load for Stiffened Cylindrical Shells

2018 ◽  
Vol 69 (8) ◽  
pp. 2000-2004 ◽  
Author(s):  
Maria Zaharia ◽  
Alexandru Pupazescu ◽  
Cristian Mihai Petre
Keyword(s):  
Numerical Analysis ◽  
Structural Analysis ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
The Real ◽  
Axial Buckling ◽  
Real Geometry ◽  
Stiffened Cylindrical Shells

As demonstrated in numerous theoretical and experimental studies [1], the buckling behaviour of stiffened cylindrical shells (SCS) is strongly influenced by the presence of geometric imperfections caused by the manufacturing process and/or exploitation. Therefore, the design norms recommend the use of reduction coefficients with very low values, resulting in a significant reduction of the maximum load applied. In order to calculate the critical buckling load as accurately as possible it is necessary to know the real geometry of SCS. In case of SCS, the structural analysis based on the use of the finite element method (FEM), using models that reflect the real geometry of the shell determined from measurements, lead to a better evaluation of the critical buckling load. The structural analysis with FEM is accepted more and more by standards, EN 1993-1-6:2007 [2] specifying the types of numerical analysis accepted for cylindrical shells. The aim of this study is to compare the results concerning the critical buckling load for SCS under axial compression, obtained with both the analytical and FEM methods for real geometries obtained from measurements. For this purpose, scale models of SCS were used, for which were determined, by measuring, the values of the deviations from the median radius at several points on the shells surface. These deviations were then incorporated in the numerical analysis with FEM and it was determined, for each cylindrical shell, the value of the critical axial buckling load, by using geometrically nonlinear analysis. In order to validate the results of the numerical analysis, the analysed SCS were subjected to axial compression within an experimental program and the experimental data were compared with the results established on the basis of analytical and numerical calculation.

Buckling Analysis and Optimization of Stiffened Cylindrical Shells under Uniform Axial Compression

2011 ◽  
Vol 462-463 ◽  
pp. 88-93
Author(s):  
Xing Hua Chen ◽  
Lian Chun Long
Keyword(s):  
Axial Compression ◽  
Cylindrical Shells ◽  
Optimization Procedure ◽  
Calculation Model ◽  
Buckling Load ◽  
Element Analysis ◽  
Range Restriction ◽  
Critical Buckling Load ◽  
Set Up ◽  
Stiffened Cylindrical Shells

Thin cylindrical shells are widely used in modern structures. When the structures are under axial compression, inflectional destruction happens early. In order to design reasonable and reliable shell structures, stiffened cylindrical shells are applied in the dissertation, ANSYS, an valid finite element analysis software, is employed to redevelop and set up parameter calculation model, subjected to volume and variables value range restriction, the structure’s critical buckling load is the objective, and the serial linear programming optimization procedure is executed as well as the optimized thickness of shell and the size of stiffeners are gained accordingly. The critical buckling load of the structure is obviously increased after optimization, and the feasibility of this method is validated due to the comparison with the numerical and theoretical result.

Axial Buckling of Cylindrical Shells With Prismatic Imperfections

1974 ◽  
Vol 41 (3) ◽  
pp. 731-736 ◽  
Author(s):  
P. Bhatia ◽  
C. D. Babcock
Keyword(s):  
Axial Compression ◽  
Cylindrical Shells ◽  
Numerical Results ◽  
Geometric Parameters ◽  
Buckling Load ◽  
Axial Buckling ◽  
Circular Cylindrical Shells

The effect of prismatic imperfections on the buckling load of circular cylindrical shells under axial compression is examined by considering the problem as one of interaction between panels forming the shell. The imperfections are in the form of flat spots. Numerical results are presented to show the effect of shell geometric parameters and the number, size, and the type of flat spots on the buckling load.

Buckling of 2D-FG Cylindrical Shells under Combined External Pressure and Axial Compression

2013 ◽  
Vol 5 (03) ◽  
pp. 391-406 ◽  
Author(s):  
R. Mohammadzadeh ◽  
M. M. Najafizadeh ◽  
M. Nejati
Keyword(s):  
Cylindrical Shell ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Axial Direction ◽  
External Pressure ◽  
Functionally Graded ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
Classical Shell Theory ◽  
The Stability

AbstractThis paper presents the stability of two-dimensional functionally graded (2D-FG) cylindrical shells subjected to combined external pressure and axial compression loads, based on classical shell theory. The material properties of functionally graded cylindrical shell are graded in two directional (radial and axial) and determined by the rule of mixture. The Euler’s equation is employed to derive the stability equations, which are solved by GDQ method to obtain the critical mechanical buckling loads of the 2D-FG cylindrical shells. The effects of shell geometry, the mechanical properties distribution in radial and axial direction on the critical buckling load are studied and compared with a cylindrical shell made of 1D-FGM. The numerical results reveal that the 2D-FGM has a significant effect on the critical buckling load.

Buckling of Edge Damaged, Cylindrical Composite Shells

1989 ◽  
Vol 56 (1) ◽  
pp. 121-126 ◽  
Author(s):  
M. Sabag ◽  
Y. Stavsky ◽  
J. B. Greenberg
Keyword(s):  
Boundary Conditions ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Buckling Load ◽  
Composite Shells ◽  
Gradual Reduction ◽  
Critical Buckling Load ◽  
Anisotropic Composite ◽  
The Stability ◽  
Edge Damage

The stability of thin composite layered anisotropic cylindrical shells under axial compression is considered for the case of nonuniform boundary conditions. Such conditions are employed to model the situation where there is edge damage to the shell. The influence of weakening or a crack at an edge on the critical buckling load of a variety of single and multilayered shells is investigated. Results indicate that isotropic shells exhibit a rather sudden steep reduction in the critical buckling load for relatively small edge damage. However, some anisotropic composite shells may not be so sensitive and, in contrast, only a gradual reduction may be brought about by the edge damage. The degree of sensitivity to edge damage appears to be dependent, in some complex fashion, on the various geometric and physical shell parameters.

RELIABILITY ASSESSMENT OF AXIALLY COMPRESSED COMPOSITE CYLINDRICAL SHELLS WITH RANDOM IMPERFECTIONS

2011 ◽  
Vol 11 (02) ◽  
pp. 215-236 ◽  
Author(s):  
MATTEO BROGGI ◽  
ADRIANO CALVI ◽  
GERHART I. SCHUËLLER
Keyword(s):  
Mathematical Models ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Reliability Assessment ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Experimental Results ◽  
Drastic Decrease ◽  
Different Types ◽  
Probability And Statistics

Cylindrical shells under axial compression are susceptible to buckling and hence require the development of enhanced underlying mathematical models in order to accurately predict the buckling load. Imperfections of the geometry of the cylinders may cause a drastic decrease of the buckling load and give rise to the need of advanced techniques in order to consider these imperfections in a buckling analysis. A deterministic buckling analysis is based on the use of the so-called knockdown factors, which specifies the reduction of the buckling load of the perfect shell in order to account for the inherent uncertainties in the geometry. In this paper, it is shown that these knockdown factors are overly conservative and that the fields of probability and statistics provide a mathematical vehicle for realistically modeling the imperfections. Furthermore, the influence of different types of imperfection on the buckling load are examined and validated with experimental results.

Axisymmetric Buckling of Ring-Stiffened Cylindrical Shells Under Axial Compression

1965 ◽  
Vol 9 (02) ◽  
pp. 66-73
Author(s):  
Thein Wah
Keyword(s):  
Finite Difference ◽  
Axial Compression ◽  
Torsional Rigidity ◽  
Cylindrical Shells ◽  
Axisymmetric Buckling ◽  
Circular Cylindrical Shells ◽  
Stiffened Cylindrical Shells

The possibility of axisymmetric modes of buckling of ring-stiffened circular cylindrical shells under axial compression is investigated by the use of finite-difference calculus. The theory accounts for both the extensional as well as torsional rigidity of the rings.

Critical Buckling Load of Triple-Walled Carbon Nanotube Based on Nonlocal Elasticity Theory

2020 ◽  
Vol 62 ◽  
pp. 108-119
Author(s):  
Tayeb Bensattalah ◽  
Ahmed Hamidi ◽  
Khaled Bouakkaz ◽  
Mohamed Zidour ◽  
Tahar Hassaine Daouadji
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Axial Compression ◽  
Buckling Load ◽  
Small Scale ◽  
Beam Model ◽  
Buckling Loads ◽  
Critical Buckling Load ◽  
Nonlocal Continuum Theory ◽  
Walled Carbon Nanotubes

The present paper investigates the nonlocal buckling of Zigzag Triple-walled carbon nanotubes (TWCNTs) under axial compression with both chirality and small scale effects. Based on the nonlocal continuum theory and the Timoshenko beam model, the governing equations are derived and the critical buckling loads under axial compression are obtained. The TWCNTs are considered as three nanotube shells coupled through the van der Waals interaction between them. The results show that the critical buckling load can be overestimated by the local beam model if the small-scale effect is overlooked for long nanotubes. In addition, a significant dependence of the critical buckling loads on the chirality of zigzag carbon nanotube is confirmed, and these are then compared with: A single-walled carbon nanotubes (SWCNTs); and Double-walled carbon nanotubes (DWCNTs). These findings are important in mechanical design considerations and reinforcement of devices that use carbon nanotubes.

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