Non-linear lower bounds for shell buckling design (original) (raw)
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Buckling of thin shells: Recent advances and trends
This paper provides a review of recent research advances and trends in the area of thin shell buckling. Only the more important and interesting aspects of recent research, judged from a personal view point, are discussed. In particular, the following topics are given emphasis: (a) imperfections in real structures and their influence; (b) buckling of shells under local/non-uniform loads and localized compressive stresses; and (c) the use of computer buckling analysis in the stability design of complex thin shell structures.
BUCKLING ANALYSIS OF SHELLS SUBJECTED TO COMBINTED LOADS
IAEME Publication, 2014
A semi-analytical isoparametric finite element with three nodes per element and five degrees of freedom per node has been used for the solution. Moderately thick shell theory has been used for the analysis. Second order strains with the in plane and transverse non-linear terms are used for the derivation of geometric matrix. Full Fourier expansion is used in the circumferential direction to overcome the coupling that arises due to material anisotropy and torque prestress. Comparison of the results obtained due to finite element is made with simplified solutions using two thin shell theories with and without shear deformation. The effects of combined load (axial compression and external pressure) on pre-buckling characteristics of composite circular cylindrical and conical shells of various geometric properties have been presented.
Buckling design of conical shells based on validated numerical models
Thin-Walled Structures, 1998
In most shell buckling codes, guidance on the design of conical shells is restricted to unstiffened cones and even in this case the clauses are based on the procedures for cylindrical shells. Virtually no guidance is offered on stiffened cones and the particular characteristics of conical shells are not treated in detail. In this paper, use is made of finite element analysis to quantify critical elastic response and imperfection sensitivity through numerical models, whose adequacy has been quantified through comparisons with test data. The finite element results obtained were aimed at validating existing design recommendations for unstiffened cones and at developing a design approach for stringer-stiffened cones under compression, with a philosophy and format compatible with the European Shell Buckling Recommendations (ECCS).
Buckling Load of Thin Spherical Shells Based on the Theorem of Work and Energy
International Journal of Engineering and Technology, 2013
Thin spherical shells usually fail due to buckling. An empirical equation to predict their buckling load is derived based on the theorem of work done and energy released in the inversion of a section of a shell and nonlinear finite element (FE) modeling done using ABAQUS to determine their post-buckling behavior. It is observed that the initial buckling is sensitive to initial geometrical imperfections but the post-buckling load is little influenced. Therefore, the post-buckling load is used to predict a more realistic load as compared to classical buckling theory prediction
Towards a rationally based elastic-plastic shell buckling design methodology
Thin-Walled Structures, 1995
The 'reduced stiffness method' for the analysis of shell buckling was developed to overcome a trend towards increasingly sophisticated analysis that has become divorced from its basically simple underlying physics. This paper outlines the developments of the reduced stiffness method from its origins in the late 1960s, through its experimental confirmation, generalisation and elaboration over the past 20 years, to its more recent consolidation using carefully controlled non-linear numerical experiments. It is suggested that the method has now reached a stage where it could profitably be adopted as a basis for an improved shell buckling design methodology.
Journal of the International Association for Shell and Spatial Structures, 2017
This paper analyses the buckling shapes of spherical shells subjected to concentrated load. A theoretical investigation, based upon geometric considerations, shows a variety of possible buckling shapes, including polygonal ones. The results show that there exists a certain difference between the geometric behavior of shells characterized by different radius-thickness ratios. An analogy between the buckling edge of the shell and a compressed planar elastic ring is also shown, which gives a better view on the point of transformation of the buckling edge from a circle to a polygon. The results of numerical and experimental analyses are also exhibited to verify the theoretical achievements.
Buckling of thin-walled cylindrical shells under axial compression
International Journal for Numerical Methods in Engineering, 2009
Lightweight thin-walled cylindrical shells subjected to external loads are prone to buckling rather than strength failure. The buckling of an axially compressed shell is studied using analytical, numerical and semi-empirical models. An analytical model is developed using the classical shell small deflection theory. A semi-empirical model is obtained by employing experimental correction factors based on the available test data in the theoretical model. Numerical model is built using ANSYS finite element analysis code for the same shell. The comparison reveals that the analytical and numerical linear model results match closely with each other but are higher than the empirical values. To investigate this discrepancy, non-linear buckling analyses with large deflection effect and geometric imperfections are carried out. These analyses show that the effects of non-linearity and geometric imperfections are responsible for the mismatch between theoretical and experimental results. The effect of shell thickness, radius and length variation on buckling load and buckling mode has also been studied. Copyright © 2009 John Wiley & Sons, Ltd.
The Bulletin of the Polytechnic Institute of Jassy, Construction. Architecture Section, 2012
The problem of dynamic stability is substantially more complex than the buckling analysis of a shell subjected to static loads. The fundamental aim of this paper is to present criteria for determining the critical load of dynamic buckling of thin shell. Another purpose of establishing such criteria is to guide engineers scientists and researchers dealing with such problems, for a better comparison verification and a validation of their experimental or numerical results. To illustrate the application of these criteria, two examples have been studied.
Elastoplastic buckling and collapse of spherical shells under combined loadings
Thin-Walled Structures, 2018
In this paper, the buckling behavior of a complete spherical shell under external pressure and of a half-sphere under torsion are first investigated. Several parametric studies are performed, which rely on the European Recommendations framework (ECCS text), so as to identify the different key parameters of the corresponding buckling capacity curves and lead up to both a qualitative and quantitative discussion about the imperfection sensitivity of such structures under each fundamental load. The related results allow us to completely describe the buckling behavior of a spherical shell under combined external pressure and circumferential shear by means of interactive buckling curves, without the need of many supplementary computations for any arbitrary combined loading case.