An experimental study of plastic buckling of a simply supported plate under edge thrusts

1978 ◽  
Vol 29 (1-4) ◽  
pp. 257-267 ◽  
Author(s):  
L. Dietrich ◽  
W. Kawahara ◽  
A. Phillips
Keyword(s):  
Experimental Study ◽  
Plastic Buckling ◽  
Simply Supported

The Plastic Buckling of Axially Compressed Square Tubes

1992 ◽  
Vol 59 (2) ◽  
pp. 276-282 ◽  
Author(s):  
S. Li ◽  
S. R. Reid
Keyword(s):  
Deformation Theory ◽  
Buckling Analysis ◽  
Rectangular Plates ◽  
Plastic Buckling ◽  
Buckling Mode ◽  
Important Conclusion ◽  
Simply Supported ◽  
Edge Conditions ◽  
Crushing Behavior ◽  
Incremental Theory Of Plasticity

A plastic buckling analysis for axially compressed square tubes is described in this paper. Deformation theory is used together with the realistic edge conditions for the panels of the tube introduced in our previous paper (Li and Reid, 1990), referred to hereafter as LR. The results obtained further our understanding of a number of problems related to the plastic buckling of axially compressed square tubes and simply supported rectangular plates, which have remained unsolved hitherto and seem rather puzzling. One of these is the discrepancy between experimental results and the results of plastic buckling analysis performed using the incremental theory of plasticity and the unexpected agreement between the results of calculations based on deformation theory for plates and experimental data obtained from tests conducted on tubes. The non-negligible difference between plates and tubes obtained in the present paper suggests that new experiments should be carried out to provide a more accurate assessment of the predictions of the two theories. Discussion of the results herein also advances our understanding of the compact crushing behavior of square tubes beyond that given in LR. An important conclusion reached is that strain hardening cannot be neglected for the plastic buckling analysis of square tubes even if the degree of hardening is small since doing so leads to an unrealistic buckling mode.

Experimental Study of Dynamic Interaction Between a Steam Generator Tube and an Anti-Vibration Bar

2010 ◽  
Author(s):  
V. Lalonde ◽  
A. Ross ◽  
M. J. Pettigrew ◽  
I. Nowlan
Keyword(s):  
Experimental Study ◽  
Dynamic Behavior ◽  
Steam Generator ◽  
Contact Force ◽  
Dynamic Interaction ◽  
Work Rate ◽  
Fretting Wear ◽  
Steam Generators ◽  
Simply Supported ◽  
Excitation Force

A first experimental work was previously carried out to study the dynamic behavior of a tube simply supported at both ends in interaction with an anti-vibration bar at mid-span. This paper presents modifications to the previous setup with the aim of improving the accuracy of the results. A comparison of the dynamic behavior of the tube is made between both setups. The objective of this experimental study is to characterize the vibration behavior of U-tubes found in steam generators of nuclear power plants. Indeed, two-phase cross-flow in the U-tubes section of steam generators can cause many problems related to vibration. In fact, flow-induced vibration of the U-tubes can cause impacts or rubbing of the tubes against their flat bar supports. Variation of the clearance between the AVB and the U-tubes may lead to ineffective supports. The resulting in-plane and out-of-plane motions of the tubes are causing fretting-wear and impact abrasion. In this study, the clearance between the tube and the AVB, as well as the amplitude, form and frequency of the excitation force are controlled parameters. The first two modes of the tube are studied. The modifications made to the setup lead to significant improvements in the results. The natural frequencies of both setups are compared to theoretical values. The difference between experimental and theoretical frequencies confirms that the new setup better represents the theoretical model of a simply supported tube. The damping of both setups is also compared to values found in literature. The results show that the new setup is more representative of realistic steam generator situations. Compared to the first setup, the displacements of the new setup clearly indicate that the movement of the tube is mostly parallel to the flat bar and in the same direction as the excitation force. The whirling motion of the tube is prevented in the new setup. The accuracy of the contact force as a function of clearance was also improved. The use of more sensitive force sensors helped to reduce the noise level of the contact force. Finally, the dynamic interaction between the tube and the AVB, defined by the fretting wear work-rate, presents a more consistent behavior. The maximum work-rate occurs when the tube is excited around the second mode for clearance between −0.10 and 0.00 mm. Such clearance between the tube and the AVB should then be avoided to minimize fretting damage.

On the Effect of Residual Stresses in the Plastic Buckling of Columns - A Model Study

1985 ◽  
Vol 9 (4) ◽  
pp. 210-223
Author(s):  
D. Camotim ◽  
J. Roorda
Keyword(s):  
Experimental Study ◽  
Residual Stresses ◽  
Maximum Load ◽  
Plastic Range ◽  
Plastic Buckling ◽  
Model Study ◽  
Geometrical Imperfections ◽  
Post Buckling ◽  
Linear And Nonlinear ◽  
Set Up

The bifurcation load and post-buckling behaviour of perfectly elastic columns is not affected by the presence of residual stresses. However, this is not the case when bifurcation occurs in the plastic range. In this paper, an analytical and experimental study of a column model is carried out, in order to investigate the influence of residual stresses in plastic buckling, namely, in the lowest bifurcation load and corresponding post-buckling behaviour. Initial geometrical imperfections are also taken into account and a sensitivity analysis is performed, in which the combined effect of both factors on the strength and maximum load supported by the structure is studied. Two elastic-plastic stress-strain relations are considered, with linear and nonlinear strain-hardening respectively. An experiment simulating the behaviour of the model is also presented. The experimental set-up is described and the experimental results are displayed and compared with the analysis.

Effect of Imperfections on the Plastic Buckling of Rectangular Plates

1975 ◽  
Vol 42 (1) ◽  
pp. 115-120 ◽  
Author(s):  
K. W. Neale
Keyword(s):  
Experimental Data ◽  
Variational Principle ◽  
Buckling Load ◽  
Rectangular Plates ◽  
Plastic Buckling ◽  
Simply Supported ◽  
Initial Imperfections

The effect of initial imperfections in geometry on the plastic buckling of simply supported compressed rectangular plates is examined. The analysis, which is based on the application of a Reissner-type variational principle, indicates that the buckling load can be highly imperfection-sensitive; and that a consideration of small imperfections in geometry could provide results which compare favorably with experimental data.

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