Background of ABS Buckling Strength Assessment Criteria for Cylindrical Shells in Offshore Structures

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Hai-Hong Sun ◽  
Pao-Lin Tan
Keyword(s):  
Cylindrical Shells ◽  
Experimental Studies ◽  
Theoretical Work ◽  
Offshore Structures ◽  
Assessment Criteria ◽  
Test Results ◽  
Strength Assessment ◽  
Buckling Strength ◽  
Shell Buckling ◽  
Buckling Behavior

Cylindrical shells, unstiffened or stiffened with rings and/or stringers, are commonly used in offshore structures as main loading-carrying members. Comprehensive theoretical work and experimental studies on the buckling behavior of cylindrical shells have been carried out in the past. The increasing offshore application of stiffened cylindrical shells has raised some new challenges that need to be addressed. This paper provides the fundamental principles and technical background of the ABS buckling strength assessment criteria for cylindrical shells applied in offshore structures. The accuracy of ABS buckling criteria for assessing the cylindrical shells is established by benchmarking the results against an extensive database of test results assembled by American Bureau of Shipping. The results are also compared against current recognized offshore standards, such as API Bulletins 2U and DnV CN30.1. It is demonstrated that the ABS criteria provide very effective and sufficiently accurate predictions for the cylindrical shell buckling calculations.

Background of ABS Buckling Strength Assessment Criteria for Cylindrical Shells in Offshore Structures

2006 ◽  
Author(s):  
Hai-Hong Sun ◽  
Pao-Lin Tan
Keyword(s):  
Cylindrical Shells ◽  
Experimental Studies ◽  
Theoretical Work ◽  
Offshore Structures ◽  
Assessment Criteria ◽  
Test Results ◽  
Strength Assessment ◽  
Buckling Strength ◽  
Shell Buckling ◽  
Buckling Behavior

Cylindrical shells, unstiffened or stiffened with rings and/or stringers are commonly used in offshore structures as main loading-carrying members. Comprehensive theoretical work and experimental studies on the buckling behavior of cylindrical shells have been carried out in the past. The increasing offshore application of stiffened cylindrical shells has raised some new challenges that need to be addressed. This paper provides the fundamental principles and technical background of the ABS buckling strength assessment criteria for cylindrical shells applied in offshore structures. The accuracy of ABS buckling criteria for assessing the cylindrical shells is established by benchmarking the results against an extensive database of test results assembled by American Bureau of Shipping. The results are also compared against current recognized offshore standards, such as API Bulletins 2U and DnV CN30.1. It is demonstrated that the ABS criteria provide very effective and sufficiently accurate predictions for the cylindrical shell buckling calculations.

Buckling Behavior of Elliptical Shells of Changing Thickness under Uniform Axial Compression

2013 ◽  
Vol 351-352 ◽  
pp. 492-496 ◽  
Author(s):  
Li Wan ◽  
Lei Chen
Keyword(s):  
Axial Compression ◽  
Cylindrical Shells ◽  
Imperfection Sensitivity ◽  
Buckling Mode ◽  
Buckling Strength ◽  
Shell Buckling ◽  
Buckling Behavior ◽  
Structural Applications ◽  
Post Buckling ◽  
Shell Geometry

Many elliptical shells are used in structural applications in which the dominant loading condition is axial compression. Due to the fact that the radius varies along the cross-section midline, the buckling behavior is more difficult to identify than those of cylindrical shells. The general concerned aspects in cylindrical shell buckling analyses such as the buckling mode, the pre-buckling deformation and post-buckling deformation are all quite different related to specific elliptical shell geometry. The buckling behavior of elliptical cylindrical shells with uniform thickness has been widely studied by many researchers. However, the thickness around the circumference may change for some specific structural forms, the femoral neck for example, which makes the buckling behavior more complex. It is known that the buckling strength of thin cylindrical shells is quite sensitive to imperfections, so it is natural to explore the imperfection sensitivity of elliptical shells. This paper explores the buckling behavior of imperfect elliptical shells under axial compression. It is hoped that the results will make a useful contribution in this field.

Nonlinear Buckling Behaviour of Imperfect Cylindrical Shells under Global Bending in the Elastic-Plastic Range

2012 ◽  
Vol 204-208 ◽  
pp. 1045-1052
Author(s):  
Lei Chen ◽  
Yi Liang Peng ◽  
Li Wan
Keyword(s):  
Cylindrical Shells ◽  
Plastic State ◽  
Plastic Range ◽  
Nonlinear Buckling ◽  
Buckling Strength ◽  
Elastic Plastic ◽  
Capacity Curves ◽  
Shell Buckling ◽  
Buckling Behavior ◽  
Structural Applications

Many thin cylindrical shells are used in structural applications in which the dominant loading condition is global bending. Key examples include chimneys, tubular piles, wind generation towers and tall silos. Their thickness lies in a tricky range which is extremely thin for the structural tube community and very thick for the shell buckling community. The buckling strength of these structures is dominated by extensive plasticity, but the fully plastic state is usually far from being attained. This paper explores the buckling strength of imperfect thin cylindrical shells under global bending in the elastic-plastic range. The capacity curves of the new Eurocode EN 1993-1-6 (2007) are used to match the final results. The results show that the capacity curves can capture this buckling behavior accurately and safely for different types of material models. It is assumed that the shell is held circular by rings or boundaries at reasonable intervals, effectively restraining ovalisation. It is hoped that these results will make a useful contribution towards resolving the misunderstandings and controversy that has been evident in this field in recent years.

Buckling of Thin Cylindrical Shells Under Locally Elevated Compressive Stresses

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
J. Michael Rotter ◽  
Minjie Cai ◽  
J. Mark F. G. Holst
Keyword(s):  
Stress State ◽  
Cylindrical Shells ◽  
Peak Stress ◽  
Theoretical Research ◽  
Design Rule ◽  
Uniform Stress ◽  
Geometric Imperfection ◽  
Buckling Strength ◽  
Shell Buckling ◽  
Compressive Stresses

Thin cylindrical shells used in engineering applications are often susceptible to failure by elastic buckling. Most experimental and theoretical research on shell buckling relates only to simple and relatively uniform stress states, but many practical load cases involve stresses that vary significantly throughout the structure. The buckling strength of an imperfect shell under relatively uniform compressive stresses is often much lower than that under locally high stresses, so the lack of information and the need for conservatism have led standards and guides to indicate that the designer should use the buckling stress for a uniform stress state even when the peak stress is rather local. However, this concept leads to the use of much thicker walls than is necessary to resist buckling, so many knowledgeable designers use very simple ideas to produce safe but unverified designs. Unfortunately, very few scientific studies of shell buckling under locally elevated compressive stresses have ever been undertaken. The most critical case is that of the cylinder in which locally high axial compressive stresses develop extending over an area that may be comparable with the characteristic size of a buckle. This paper explores the buckling strength of an elastic cylinder in which a locally high axial membrane stress state is produced far from the boundaries (which can elevate the buckling strength further) and adjacent to a serious geometric imperfection. Care is taken to ensure that the stress state is as simple as possible, with local bending and the effects of internal pressurization eliminated. The study includes explorations of different geometries, different localizations of the loading, and different imperfection amplitudes. The results show an interesting distinction between narrower and wider zones of elevated stresses. The study is a necessary precursor to the development of a complete design rule for shell buckling strength under conditions of locally varying axial compressive stress.

Imperfection Sensitivity of Laminated Cylindrical Shells by Full and Initial Post-Buckling Analyses

Aerospace ◽  
2004 ◽  
Author(s):  
Izhak Sheinman ◽  
Mahmood Jabareen
Keyword(s):  
Structural Engineering ◽  
Cylindrical Shells ◽  
Nonlinear Behavior ◽  
Test Results ◽  
Imperfection Sensitivity ◽  
Buckling Behavior ◽  
Load Carrying ◽  
Post Buckling ◽  
Linear Buckling Analysis ◽  
Laminated Cylindrical Shells

Laminated cylindrical shells are already commonly used in structural engineering, and their buckling and post-buckling behavior is of vital importance in the design of such structures. The validity of linear buckling analysis in this context, has been questioned because of the discrepancy observed between theoretical prediction and test results. The cause of this discrepancy is the fact that the nonlinear behavior of shell-like structures is generally characterized by a limit point rather than by a bifurcation point. For such structures, the load-carrying capacity depends on the level of imperfection (hence the concept “imperfection sensitivity”). The motivation is, therefore, to reduce the sensitivity rather than preventing the imperfection. For that purpose insight into the post-buckling state is called for.

PENGKAJIAN KEKUATAN BETON STRUKTUR JEMBATAN PASCA KEBAKARAN

2013 ◽  
Vol 12 (3) ◽  
Author(s):  
Sudarmadi Sudarmadi
Keyword(s):  
Compressive Strength ◽  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Test Results ◽  
Concrete Compressive Strength ◽  
Strength Assessment ◽  
Concrete Testing

In this paper a case study about concrete strength assessment of bridge structure experiencing fire is discussed. Assessment methods include activities of visual inspection, concrete testing by Hammer Test, Ultrasonic Pulse Velocity Test, and Core Test. Then, test results are compared with the requirement of RSNI T-12-2004. Test results show that surface concrete at the location of fire deteriorates so that its quality is decreased into the category of Very Poor with ultrasonic pulse velocity ranges between 1,14 – 1,74 km/s. From test results also it can be known that concrete compressive strength of inner part of bridge pier ranges about 267 – 274 kg/cm2 and concrete compressive strength of beam and plate experiencing fire directly is about 173 kg/cm2 and 159 kg/cm2. It can be concluded that surface concrete strength at the location of fire does not meet the requirement of RSNI T-12-2004. So, repair on surface concrete of pier, beam, and plate at the location of fire is required.

scholarly journals Photoionization Cross-Sections of Carbon-Like N+ Near the K-Edge (390–440 eV)

Atoms ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 27
Author(s):  
Jean-Paul Mosnier ◽  
Eugene T. Kennedy ◽  
Jean-Marc Bizau ◽  
Denis Cubaynes ◽  
Ségolène Guilbaud ◽  
...  
Keyword(s):  
High Resolution ◽  
Cross Section ◽  
Cross Sections ◽  
Experimental Studies ◽  
Photoionization Cross Section ◽  
Theoretical Work ◽  
Rydberg Series ◽  
R Matrix ◽  
Resonance Strengths ◽  
Nitrogen Ion

High-resolution K-shell photoionization cross-sections for the C-like atomic nitrogen ion (N+) are reported in the 398 eV (31.15 Å) to 450 eV (27.55 Å) energy (wavelength) range. The results were obtained from absolute ion-yield measurements using the SOLEIL synchrotron radiation facility for spectral bandpasses of 65 meV or 250 meV. In the photon energy region 398–403 eV, 1s⟶2p autoionizing resonance states dominated the cross section spectrum. Analyses of the experimental profiles yielded resonance strengths and Auger widths. In the 415–440 eV photon region 1s⟶(1s2s22p2 4P)np and 1s⟶(1s2s22p2 2P)np resonances forming well-developed Rydberg series up n=7 and n=8 , respectively, were identified in both the single and double ionization spectra. Theoretical photoionization cross-section calculations, performed using the R-matrix plus pseudo-states (RMPS) method and the multiconfiguration Dirac-Fock (MCDF) approach were bench marked against these high-resolution experimental results. Comparison of the state-of-the-art theoretical work with the experimental studies allowed the identification of new resonance features. Resonance strengths, energies and Auger widths (where available) are compared quantitatively with the theoretical values. Contributions from excited metastable states of the N+ ions were carefully considered throughout.

Shell buckling behavior investigation of individual gallium nitride hollow nanocolumn

2006 ◽  
Vol 84 (4) ◽  
pp. 439-443 ◽  
Author(s):  
S.-C. Hung ◽  
Y.-K. Su ◽  
T.-H. Fang ◽  
S.-J. Chang
Keyword(s):  
Gallium Nitride ◽  
Shell Buckling ◽  
Buckling Behavior
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