Comparison of theoretical approaches to account for geometrical imperfections of unstiffened isotropic thin walled cylindrical shell structures under axial compression

2015 ◽  
Vol 92 ◽  
pp. 1-9 ◽  
Author(s):  
Linus Friedrich ◽  
Theodor-Andres Schmid-Fuertes ◽  
Kai-Uwe Schröder
Author(s):  
Peng Jiao ◽  
Zhiping Chen ◽  
He Ma ◽  
Delin Zhang ◽  
Jihang Wu ◽  
...  

Abstract Thin-walled cylindrical shell structure not only shows the highly efficient load carrying capacity but also is vulnerable to buckling instability failure. In practical application, these structures are more easily subjected to locally distributed axial compression load, which is a more common non-uniform loading case. However, until now, the buckling behaviors of thin-walled cylindrical shells under this kind of loading case are still unclear, and there are also few relevant buckling experiments. In order to fill this research gap as well as reveal the relevant failure mechanism of thin-walled cylindrical shell structures, in this paper buckling tests of thin-walled metallic cylindrical shell structures under non-uniform axial compression loads are successfully performed. In this regard, the design and characteristics of two cylindrical shell test specimens subjected to different pattern of non-uniform compression loads are mainly introduced. Meanwhile, as the important parts for conducting this buckling experiment, the axial compression buckling test rig as well as the real-time acquisition measurement system is also presented in details. Results indicate that locally distributed axial compression loads play a pivotal role in the buckling behaviors of thin-walled cylindrical shell, not matter from the point of view of load carrying capacity, shell deformation process or failure mode. The experiments carried out in this work can be served as a benchmark for related numerical simulation afterwards. Furthermore, the obtained test results can also provide some guides for the design and application of thin-walled cylindrical shell in actual engineering.


Author(s):  
D Xing ◽  
W Chen ◽  
J Ma ◽  
L Zhao

In nature, bamboo develops an excellent structure to bear nature forces, and it is very helpful for designing thin-walled cylindrical shells with high load-bearing efficiency. In this article, the cross-section of bamboo is investigated, and the feature of the gradual distribution of vascular bundles in bamboo cross-section is outlined. Based on that, a structural bionic design for thin-walled cylindrical shells is presented, of which the manufacturability is also taken into consideration. The comparison between the bionic thin-walled cylindrical shell and a simple hollow one with the same weight showed that the load-bearing efficiency was improved by 44.7 per cent.


2007 ◽  
Vol 10 (5) ◽  
pp. 581-591 ◽  
Author(s):  
B. Prabu ◽  
N. Bujjibabu ◽  
S. Saravanan ◽  
A. Venkatraman

Generally, thin cylindrical shells are susceptible for geometrical imperfections like non-circularity, non-cylindricity, dents, swellings etc. All these geometrical imperfections decrease the static buckling strength of thin cylindrical shells, but in this paper only effect of a dent on strength of a short (L / D ∼1 and R/t = 280) stainless steel cylindrical shell is considered for analysis. The dent is modeled on the FE surface of perfect cylindrical shell for different angles of inclination and sizes at half the height of cylindrical shell. The cylindrical shells with a dent are analyzed using non-linear static buckling analysis. From the results it is found that in case of shorter dents, size and angle of inclination dents do not have much effect on static buckling strength of thin cylindrical shells, where as in the case of long dents, size and angle of inclination of dents have significant effect. But both short and long dents reduce the static buckling strength drastically.


Aerospace ◽  
2019 ◽  
Vol 6 (5) ◽  
pp. 52 ◽  
Author(s):  
Angela Russo ◽  
Andrea Sellitto ◽  
Salvatore Saputo ◽  
Valerio Acanfora ◽  
Aniello Riccio

The presence of cut-outs within thin-walled shell structures is unavoidable, holes being needed for the passage of electrical cables, fuel, or just to reduce the weight of the components. Nevertheless, the high stress concentration can lead to a premature collapse of the structure. For this reason, the preliminary design of cylindrical shell structures with holes needs a profound knowledge of the stress distribution for different loading conditions and constraints. In this paper, a parametric study of a fiber-reinforced composite shell cylinder with an elliptical cut-out has been performed. Three different loading conditions were analyzed: Tension, bending, and torsion. Ansys® script, capable of easily generating and analyzing different geometrical configurations, was used to study the dependence of the geometry on the stress distribution near the cut-out. Finally, graphical and analytical relationships were tentatively extrapolated from numerical results, aimed at linking the geometrical parameters of the cut-out to the maximum stress near the cut-out.


Author(s):  
Rolf H. Zimmermann

Abstract The performance of thin-walled structures, which are endangered by buckling, is often strongly influenced by geometrical imperfections. It is impossible to know in advance the imperfections, which will be present in the real structure. Nevertheless, their influence has to be taken into account already at the design process. Attempts to identify characteristic imperfections due to specific manufacturing processes overcome this difficulty only partly, as they do not consider imperfections coming into existence after fabrication. The remedy is, to build imperfection tolerant structures. For that purpose, a simple means to measure imperfection tolerance is defined, and a multiobjective optimization formulation is proposed to design fiber composite shell structures, which simultaneously exhibit high imperfection tolerance and high buckling load. By example of axially compressed CFRP cylindrical shells first computational and experimental results are given to demonstrate the feasibility of the concept, and to identify needs for further research.


2019 ◽  
Vol 19 (12) ◽  
pp. 1950160 ◽  
Author(s):  
Jing Zhang ◽  
Jie Xu ◽  
Xuegang Yuan ◽  
Wenzheng Zhang ◽  
Datian Niu

Some significant behaviors on strongly nonlinear vibrations are examined for a thin-walled cylindrical shell composed of the classical incompressible Mooney–Rivlin material and subjected to a single radial harmonic excitation at the inner surface. First, with the aid of Donnell’s nonlinear shallow-shell theory, Lagrange’s equations and the assumption of small strains, a nonlinear system of differential equations for the large deflection vibration of a thin-walled shell is obtained. Second, based on the condensation method, the nonlinear system of differential equations is reduced to a strongly nonlinear Duffing equation with a large parameter. Finally, by the appropriate parameter transformation and modified Lindstedt–Poincar[Formula: see text] method, the response curves for the amplitude-frequency and phase-frequency relations are presented. Numerical results demonstrate that the geometrically nonlinear characteristic of the shell undergoing large vibrations shows a hardening behavior, while the nonlinearity of the hyperelastic material should weak the hardening behavior to some extent.


2006 ◽  
Vol 06 (04) ◽  
pp. 457-474 ◽  
Author(s):  
M. A. BRADFORD ◽  
A. ROUFEGARINEJAD ◽  
Z. VRCELJ

Circular thin-walled elastic tubes under concentric axial loading usually fail by shell buckling, and in practical design procedures the buckling load can be determined by modifying the local buckling stress to account empirically for the imperfection sensitive response that is typical in Donnell shell theory. While the local buckling stress of a hollow thin-walled tube under concentric axial compression has a solution in closed form, that of a thin-walled circular tube with an elastic infill, which restrains the local buckling mode, has received far less attention. This paper addresses the local buckling of a tubular member subjected to axial compression, and formulates an energy-based technique for determining the local buckling stress as a function of the stiffness of the elastic infill by recourse to a transcendental equation. This simple energy formulation, with one degree of buckling freedom, shows that the elastic local buckling stress increases from 1 to [Formula: see text] times that of a hollow tube as the stiffness of the elastic infill increases from zero to infinity; the latter case being typical of that of a concrete-filled steel tube. The energy formulation is then recast into a multi-degree of freedom matrix stiffness format, in which the function for the buckling mode is a Fourier representation satisfying, a priori, the necessary kinematic condition that the buckling deformation vanishes at the point where it enters the elastic medium. The solution is shown to converge rapidly, and demonstrates that the simple transcendental formulation provides a sufficiently accurate representation of the buckling problem.


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