RELIABILITY ASSESSMENT OF AXIALLY COMPRESSED COMPOSITE CYLINDRICAL SHELLS WITH RANDOM IMPERFECTIONS

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.

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Postbuckling Analyses of Elastic Cylindrical Shells Under Axial Compression

Volume 3: Design and Analysis ◽

10.1115/pvp2009-77350 ◽

2009 ◽

Cited By ~ 1

Author(s):

Takaya Kobayashi ◽

Yasuko Mihara

Keyword(s):

Critical Load ◽

Axial Compression ◽

Cylindrical Shells ◽

General Purpose ◽

Experimental Results ◽

Ideal Condition ◽

Postbuckling Behavior ◽

Mode Shift ◽

Applied Loading ◽

Circular Cylindrical Shells

In designing a modern lightweight structure, it is of technical importance to assure its safety against buckling under the applied loading conditions. For this issue, the determination of the critical load in an ideal condition is not sufficient, but it is further required to clarify the postbuckling behavior, that is, the behavior of the structure after passing through the critical load. One of the reasons is to estimate the effect of practically unavoidable imperfections on the critical load, and the second reason is to evaluate the ultimate strength to exploit the load-carrying capacity of the structure. For the buckling problem of circular cylindrical shells under axial compression, a number of experimental and theoretical studies have been made by many researchers. In the case of the very thin shell that exhibits elastic buckling, experimental results show that after the primary buckling, secondary buckling takes place accompanying successive reductions in the number of circumferential waves at every mode shift on systematic (one-by-one) basis. In this paper, we traced this successive buckling of circular cylindrical shells using the latest in general-purpose FEM technology. We carried out our studies with three approaches: the arc-length method (the modified Riks method); the static stabilizing method with the aid of (artificial) damping especially, for the local instability; and the explicit dynamic procedure. The studies accomplished the simulation of successive buckling following unstable paths, and showed agreement with the experimental results.

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857 Buckling Analysis of Composite Laminated Cylindrical Shells with a Circular Cut-Out under Axial Compression

The Proceedings of Yamanashi District Conference ◽

10.1299/jsmeyamanashi.2007.235 ◽

2007 ◽

Vol 2007 (0) ◽

pp. 235-236

Author(s):

Suguru ISHIKAWA ◽

Kazumasa SUEISHI ◽

Hisao KIKUGAWA ◽

Hirakazu KASUYA

Keyword(s):

Axial Compression ◽

Cylindrical Shells ◽

Buckling Analysis ◽

Laminated Cylindrical Shells

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Buckling Analysis of Shells with a Circumferential Crack

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.306-308.55 ◽

2006 ◽

Vol 306-308 ◽

pp. 55-60

Author(s):

I.S. Putra ◽

T. Dirgantara ◽

Firmansyah ◽

M. Mora

Keyword(s):

Boundary Conditions ◽

Cylindrical Shells ◽

Buckling Analysis ◽

Numerical Results ◽

Buckling Load ◽

Numerical Analyses ◽

Radius Of Curvature ◽

Critical Buckling Load ◽

Different Boundary Conditions ◽

Circumferential Crack

In this paper, buckling analysis of cylindrical shells with a circumferential crack is presented. The analyses were performed both numerically using FEM and experimentally. The numerical analyses and experiments were conducted for several crack lengths and radius of curvature, and two different boundary conditions were applied, i.e. simply support and clamp in all sides. The results show the effect of the presence of crack to the critical buckling load of the shells. There are good agreements between experimental and numerical results.

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Effect of a Dent of Different Sizes and Angles of Inclination on Buckling Strength of a Short Stainless Steel Cylindrical Shell Subjected to Uniform Axial Compression

Advances in Structural Engineering ◽

10.1260/136943307782417735 ◽

2007 ◽

Vol 10 (5) ◽

pp. 581-591 ◽

Cited By ~ 12

Author(s):

B. Prabu ◽

N. Bujjibabu ◽

S. Saravanan ◽

A. Venkatraman

Keyword(s):

Stainless Steel ◽

Cylindrical Shell ◽

Axial Compression ◽

Cylindrical Shells ◽

Buckling Analysis ◽

Buckling Strength ◽

Non Linear ◽

Geometrical Imperfections ◽

Steel Cylindrical Shell

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.

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STRENGTH DEVELOPMENT OF CONCRETE WITH FLY ASH ADDITION

Journal of Civil Engineering and Management ◽

10.3846/13923730.2007.9636427 ◽

2007 ◽

Vol 13 (2) ◽

pp. 115-122 ◽

Cited By ~ 18

Author(s):

Marta Kosior-Kazberuk ◽

Małgorzata Lelusz

Keyword(s):

Compressive Strength ◽

Fly Ash ◽

Mathematical Models ◽

Statistical Methods ◽

Experimental Results ◽

Strength Development ◽

Hardened Concrete ◽

Test Results ◽

Different Types ◽

Compressive Strength Of Concrete

Based on experimental results, mathematical models were elaborated to predict the development of compressive strength of concrete with fly ash replacement percentages up to 30 %. Strength of concrete with different types of cement (CEM I 42.5, CEM I 32.5, CEM III 32.5), after 2, 28, 90, 180 days of curing, have been analysed to evaluate the effect of addition content, the time of curing and the type of cement on the compressive strength changes. The adequacy of equations obtained was verified using statistical methods. The test results of selected properties of binders and hardened concrete with fly ash are also included. The analysis showed that concrete with fly ash is characterised by advantageous applicable qualities.

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