Buckling of the Composite Cracked Cylindrical Shells Subjected to Axial Load

2003 ◽  
Author(s):  
A. Vaziri ◽  
H. Nayeb-Hashemi ◽  
H. E. Estekanchi
Keyword(s):  
Crack Length ◽  
Cylindrical Shells ◽  
Critical Length ◽  
Pressure Vessels ◽  
Buckling Load ◽  
Mode Shapes ◽  
Buckling Mode ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Composite Cylindrical Shells

Cylindrical shells constitute the main structural components in pressure vessels and pipelines. Cylindrical shells made of fiber-reinforced composites are now being considered in the design of many components due to their high specific strength and stiffness. Buckling is one of the main failure considerations, when designing the cylindrical shells. The buckling behavior of the composite cylindrical shells can severely the compromised by introducing defect in the structure, due to high stress field generated around these defects. Defects could be generated during service due to cyclic loading or during manufacturing. A reliable operation of these structures require to understand the effects of these defects on the bucking of cylindrical shells. Finite Element Analyses are performed to study the buckling behaviour of composite cylindrical shells with and without a crack, under an axial compressive loading. The effects of the plies angle on the buckling loads and buckling mode shapes of the composite cylindrical shells are studied. Furthermore, the effects of the crack length and its orientation on the buckling loads of the composite cylindrical shells are investigated. The results indicate that the global buckling loads and mode shapes of the cracked composite shells are not significantly sensitive to the presence of the defect, for shells with a crack length less than a critical length. This critical crack length depends on the crack orientation, composite ply angles, ply sequence and the cylinder geometry. For shells with a crack longer than the critical length, the buckling load reduces and the local buckling mode at the crack tip prevail the buckling behavior of the composite cylindrical shell. The optimum ply angle for attaining the maximum buckling load is specified.

Buckling of Cracked Cylindrical Shells With Internal Pressure Subjected to an Axial Load

2002 ◽  
Author(s):  
A. Vaziri ◽  
H. E. Estekanchi ◽  
H. Nayeb-Hashemi
Keyword(s):  
Internal Pressure ◽  
Crack Length ◽  
Cylindrical Shells ◽  
High Stress ◽  
Pressure Vessels ◽  
Buckling Load ◽  
Critical Crack Length ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Crack Angle

Cylindrical shells constitute the main structural component in pressure vessels and pipelines. Buckling is one of the main failure considerations when designing these cylindrical shells. Defects such as cracks may develop during manufacturing or service life of these structures. These defects can severely affect their buckling behavior due to high stress field generated around these defects. Finite Element Analyses are performed to study the buckling behavior of cylindrical shells with and without a crack, under various internal pressures. Effects of crack length and its orientation on the buckling loads of cylindrical shells having a through or a thumbnail crack are studied. The results show that the buckling loads are not significantly affected for cylindrical shells with a crack less than a critical length. However, longer cracks cause local buckling of the cracked shells and can severely affect their buckling loads. This critical crack length depends on the crack orientation and the shell internal pressure. The results indicate that the buckling loads of cracked shells with internal pressure are quite sensitive to the crack angle. For cylindrical shells with an axial crack, the first buckling load drastically reduces with increasing the shell internal pressure. In contrast, the buckling load increases with the shell internal pressure for circumferentially cracked shells. The buckling loads of cracked shells with internal pressure are quite sensitive to crack angle. However, the bucking loads are little dependent to the crack angle for shells with no internal pressure.

Buckling of Fully Embedded Single Piles by Using the Modified Vlasov Foundation Model

2017 ◽  
Vol 17 (01) ◽  
pp. 1750007 ◽  
Author(s):  
Tao Deng ◽  
Qijian Liu ◽  
Ming Huang
Keyword(s):  
Elastic Medium ◽  
Material Properties ◽  
Iterative Procedure ◽  
Mode Shapes ◽  
Modulus Ratio ◽  
Buckling Mode ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Foundation Model ◽  
Single Piles

An analytical method for analyzing the buckling of fully embedded single piles in an elastic medium is developed. The medium is simulated by the modified Vlasov foundation model. The governing differential equations of the pile and the surrounding elastic medium in the soil–pile system are derived by the variational principle, which are coupled when the pile buckles. A numerical iterative procedure is introduced to obtain the buckling loads and the corresponding mode shapes of the pile. Parametric study is performed to investigate the effects of the material properties of the soil–pile system on the buckling capacity of the pile. Numerical results show that the medium stiffness has significant influence on the buckling mode when the modulus ratio of the soil to the pile is large. Moreover, the effect of Poisson’s ratio of the soil on the buckling behavior of pile is negligible.

On Establishing Buckling Knockdowns for Imperfection-Sensitive Shell Structures

2018 ◽  
Vol 85 (9) ◽  
Author(s):  
S. Gerasimidis ◽  
E. Virot ◽  
J. W. Hutchinson ◽  
S. M. Rubinstein
Keyword(s):  
Cylindrical Shells ◽  
Strong Dependence ◽  
Elastic Shell ◽  
External Pressure ◽  
Buckling Load ◽  
Spherical Shells ◽  
Nonlinear Buckling ◽  
Buckling Loads ◽  
Buckling Behavior ◽  
Global Buckling

This paper investigates issues that have arisen in recent efforts to revise long-standing knockdown factors for elastic shell buckling, which are widely regarded as being overly conservative for well-constructed shells. In particular, this paper focuses on cylindrical shells under axial compression with emphasis on the role of local geometric dimple imperfections and the use of lateral force probes as surrogate imperfections. Local and global buckling loads are identified and related for the two kinds of imperfections. Buckling loads are computed for four sets of relevant boundary conditions revealing a strong dependence of the global buckling load on overall end-rotation constraint when local buckling precedes global buckling. A reasonably complete picture emerges, which should be useful for informing decisions on establishing knockdown factors. Experiments are performed using a lateral probe to study the stability landscape for a cylindrical shell with overall end rotation constrained in the first set of tests and then unconstrained in the second set of tests. The nonlinear buckling behavior of spherical shells under external pressure is also examined for both types of imperfections. The buckling behavior of spherical shells is different in a number of important respects from that of the cylindrical shells, particularly regarding the interplay between local and global buckling and the post-buckling load-carrying capacity. These behavioral differences have bearing on efforts to revise buckling design rules. The present study raises questions about the perspicacity of using probe force imperfections as surrogates for geometric dimple imperfections.

Dynamic Buckling of Externally Pressurized Imperfect Cylindrical Shells

1975 ◽  
Vol 42 (2) ◽  
pp. 316-320 ◽  
Author(s):  
D. Lockhart ◽  
J. C. Amazigo
Keyword(s):  
Asymptotic Expression ◽  
Cylindrical Shells ◽  
Simple Relation ◽  
Dynamic Buckling ◽  
Fourier Component ◽  
Buckling Load ◽  
Buckling Mode ◽  
Geometric Imperfections ◽  
Circular Cylindrical Shells ◽  
Step Loading

The dynamic buckling of imperfect finite circular cylindrical shells subjected to suddenly applied and subsequently maintained lateral or hydrostatic pressure is studied using a perturbation method. The geometric imperfections are assumed small but arbitrary. A simple asymptotic expression is obtained for the dynamic buckling load in terms of the amplitude of the Fourier component of the imperfection in the shape of the classical buckling mode. Consequently, for small imperfection, there is a simple relation between the dynamic buckling load under step-loading and the static buckling load. This relation is independent of the shape of the imperfection.

Influence of Crack on the Instability of GFRP Composite Cylindrical Shells under Combined Loading

2018 ◽  
Vol 877 ◽  
pp. 453-459
Author(s):  
B. Angelina Catherine ◽  
R.S. Priyadarsini
Keyword(s):  
Structural Integrity ◽  
Cylindrical Shells ◽  
Laminated Composite ◽  
External Pressure ◽  
Industrial Applications ◽  
Combined Loading ◽  
Finite Element Software ◽  
Buckling Behavior ◽  
Thin Walled ◽  
Composite Cylindrical Shells

Buckling is a prominent condition of instability caused to a shell structure as a result of axial loadings. The process of buckling becomes more complex while analyzing thin walled structures like shells. Today such thin walled laminated composite shells are gaining more importance in many defense and industrial applications since they have greater structural efficiency and performance in relation to isotropic structures. Comprehensive understanding of the buckling response of shell structures is necessary to assure the integrity of these shells during their service life. The presence of defects, such as cracks, may severely compromise their buckling behavior and jeopardize the structural integrity. This work aims in conducting numerical analysis of cracked GFRP (Glass fibre-reinforced polymer) composite cylindrical shells under combined loading to study the effect of crack size on the buckling behavior of laminated composite cylindrical shells with different lay-up sequences. The numerical analyses were carried out using the finite element software, ABAQUS in order to predict the buckling behaviour of cracked laminated composite cylinders subject to different combinations of axial compression, torsion, internal pressure and external pressure from the interaction buckling curves.

Optimization and Antioptimization of Buckling Load for Composite Cylindrical Shells Under Uncertainties

AIAA Journal ◽  
2012 ◽  
Vol 50 (7) ◽  
pp. 1513-1524 ◽  
Author(s):  
Isaac Elishakoff ◽  
Benedikt Kriegesmann ◽  
Raimund Rolfes ◽  
Christian Hühne ◽  
Alexander Kling
Keyword(s):  
Cylindrical Shells ◽  
Buckling Load ◽  
Composite Cylindrical Shells

Initial Postbuckling Behavior of Imperfect, Antisymmetric Cross-Ply Cylindrical Shells Under Torsion

1987 ◽  
Vol 54 (1) ◽  
pp. 174-180 ◽  
Author(s):  
David Hui ◽  
I. H. Y. Du
Keyword(s):  
Cylindrical Shells ◽  
Elastic Stability ◽  
Buckling Load ◽  
Postbuckling Behavior ◽  
Imperfection Sensitivity ◽  
Torsional Buckling ◽  
Buckling Mode ◽  
Young’S Moduli ◽  
Coupling Behavior ◽  
Parameter Variations

This paper deals with the initial postbuckling of antisymmetric cross-ply closed cylindrical shells under torsion. Under the assumptions employed in Koiter’s theory of elastic stability, the structure is imperfection-sensitive in certain intermediate ranges of the reduced-Batdorf parameter (approx. 4 ≤ ZH ≤ 20.0). Due to different material bending-stretching coupling behavior, the (0 deg inside, 90 deg outside) two-layer clamped cylinder is less imperfection sensitive than the (90 deg inside, 0 deg outside) configuration. The increase in torsional buckling load due to a higher value of Young’s moduli ratio is not necessarily accompanied by a higher degree of imperfection-sensitivity. The paper is the first to consider imperfection shape to be identical to the torsional buckling mode and presents concise parameter variations involving the reduced-Batdorf paramter and Young’s moduli ratio.

Buckling Analysis of Symmetric Cross-Ply Laminated Annular Plates with Carbon Nanotubes

2014 ◽  
Vol 592-594 ◽  
pp. 901-905
Author(s):  
Pankaj Kumar ◽  
Pandey Ramesh
Keyword(s):  
Carbon Nanotubes ◽  
Boundary Condition ◽  
Carbon Nanotube ◽  
Aspect Ratio ◽  
Energy Method ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Buckling Loads ◽  
Annular Plates ◽  
Buckling Behavior

The Paper presents the buckling response of composite annular plates with under uniform internal and external radial edge loads using energy method. For the equation of stability Trefftez rule is used. The paper consists of buckling behavior of laminate (90/0) s, influence of some parameters such as thickness, boundary condition, aspect ratio on buckling loads and modes are investigated. Present results are compared with other papers. In this paper the effect of % weight of carbon nanotube (MWCNT) on the buckling load is also investigated.

Sign in / Sign up

Export Citation Format

Share Document