scholarly journals Lateral Vibrations as Related to Structural Stability

1952 ◽  
Vol 19 (2) ◽  
pp. 195-204 ◽  
Author(s):  
Harold Lurie

Abstract The apparently different physical problems of lateral vibration and elastic stability are limiting cases of a single phenomenon, the more general expression being the mode of vibration with end thrust. It is shown that the square of the frequency of lateral vibration is approximately linearly related to the end load. The linear relationship is exact if the mode of free vibrations is identical to the buckling mode. In all cases, the load corresponding to zero frequency is the critical buckling load. Experimental tests were conducted on elastically restrained columns in the form of rigid rectangular frames. It was found that the relationship between the square of the frequency and the load is practically linear, and that the extrapolated load corresponding to zero frequency coincides with the buckling load. Rigid-joint trusses also were tested. In some cases the relationship between the square of the frequency and the load deviates considerably from linearity, but the approximate buckling load can be predicted. In the case of thin flat plates, tests showed that the buckling load cannot be predicted from vibration tests in practice. It is indicated that this is probably because the linear plate equations are not valid owing to initial curvatures in the plate.

1987 ◽  
Vol 54 (1) ◽  
pp. 174-180 ◽  
Author(s):  
David Hui ◽  
I. H. Y. Du

This paper deals with the initial postbuckling of antisymmetric cross-ply closed cylindrical shells under torsion. Under the assumptions employed in Koiter’s theory of elastic stability, the structure is imperfection-sensitive in certain intermediate ranges of the reduced-Batdorf parameter (approx. 4 ≤ ZH ≤ 20.0). Due to different material bending-stretching coupling behavior, the (0 deg inside, 90 deg outside) two-layer clamped cylinder is less imperfection sensitive than the (90 deg inside, 0 deg outside) configuration. The increase in torsional buckling load due to a higher value of Young’s moduli ratio is not necessarily accompanied by a higher degree of imperfection-sensitivity. The paper is the first to consider imperfection shape to be identical to the torsional buckling mode and presents concise parameter variations involving the reduced-Batdorf paramter and Young’s moduli ratio.


1957 ◽  
Vol 8 (4) ◽  
pp. 395-396 ◽  
Author(s):  
L. H. Mitchell ◽  
K. C. Rockey

Dr. Rockey, in his interesting paper on the design of vertical stiffeners for shear webs, perpetuates the idea of Timoshenko (Theory of Elastic Stability, McGraw-Hill, New York, 1936) that for stiffener rigidities above a certain value the stiffeners remain straight and the rigid stiffener buckling load is reached. It is my opinion that this is only so when the stiffeners happen to be placed along a straight node of one of the harmonics of the buckling pattern of the unstiffened plate. With unstiffened plates under shear loads, the nodes are not straight and consequently the buckling load will theoretically always increase with increase of stiffener rigidity, i.e. no buckling mode exists such that stiffeners of finite rigidity remain straight. It is suspected that Timoshenko was led to his conclusion by over-estimated buckling loads obtained by energy methods.


2021 ◽  
Vol 242 ◽  
pp. 112275
Author(s):  
Zhenya Sun ◽  
Zhenkun Lei ◽  
Ruixiang Bai ◽  
Hao Jiang ◽  
Jianchao Zou ◽  
...  

1975 ◽  
Vol 42 (2) ◽  
pp. 316-320 ◽  
Author(s):  
D. Lockhart ◽  
J. C. Amazigo

The dynamic buckling of imperfect finite circular cylindrical shells subjected to suddenly applied and subsequently maintained lateral or hydrostatic pressure is studied using a perturbation method. The geometric imperfections are assumed small but arbitrary. A simple asymptotic expression is obtained for the dynamic buckling load in terms of the amplitude of the Fourier component of the imperfection in the shape of the classical buckling mode. Consequently, for small imperfection, there is a simple relation between the dynamic buckling load under step-loading and the static buckling load. This relation is independent of the shape of the imperfection.


2014 ◽  
Vol 694 ◽  
pp. 288-291
Author(s):  
Run Ze Duan ◽  
Zhi Ying Chen ◽  
Li Jun Yang

An electrified liquid sheet injected into a dielectric moving through a viscous gas bounded by two horizontal parallel flat plates of a transverse electric field is investigated with the linear analysis method. The liquid sheet velocity profile and the gas boundary layer thickness are taken into account. The relationship between temporal growth rate and the wave number was obtained using linear stability analysis and solved using the Chebyshev spectral collocation method. The effects of the velocity profile on the stability of the electrified liquid sheet were revealed for both sinuous mode and varicose mode. The results show that the growth rate of the electrified Newtonian liquid is greater than that of corresponding Newtonian one under the same condition, and the growth rate of the sinuous mode is greater than that of the varicose mode. Keywords: instability; planar liquid sheet; velocity profile;spectral method;linear analysis


Author(s):  
A Ghorbanpour Arani ◽  
M Mohammadimehr ◽  
A R Saidi ◽  
S Shogaei ◽  
A Arefmanesh

In this article, the buckling analysis of a double-walled carbon nanotube (DWCNT) subjected to a uniform internal pressure in a thermal field is investigated. The effects of the temperature change, the surrounding elastic medium based on the Winkler model, and the van der Waals forces between the inner and the outer tubes are considered using the continuum cylindrical shell model. The small-length scale effect is also included in the present formulation. The results show that there is a unique buckling mode corresponding to each critical buckling load. Moreover, it is shown that the non-local critical buckling load is lower than the local critical buckling load. It is concluded that, at low temperatures, the critical buckling load for the infinitesimal buckling of a DWCNT increases as the magnitude of temperature change increases whereas at high temperatures, the critical buckling load decreases with the increasing of the temperature.


1963 ◽  
Vol 14 (1) ◽  
pp. 17-30 ◽  
Author(s):  
W. H. Wittrick

SummaryThe problem considered is the buckling of a rectangular plate under uniaxial compression. The ends may be either both clamped, both simply-supported or a mixture of the two. The sides may be elastically restrained against both deflection and rotation with any stiffnesses whatsoever. It is shown that the curve of buckling stress coefficient versus side ratio can be deduced in a simple manner from that of a plate with the same end conditions but with both sides simply-supported, provided only that the buckling stress coefficient and wavelength for an infinite strip with the same side conditions are known. Some correlations between the curves for the three types of end condition are discussed. It is also shown that if, for some given side ratio, the buckling mode is known, then it is always possible to deduce the rate of change of buckling stress coefficient with side ratio at that point. The argument is based upon an assumption which is shown to give very accurate results in a wide range of cases.


Author(s):  
Jose G Fueyo ◽  
Manuel Domínguez ◽  
Jose A Cabezas

This paper studies the shear stresses appearing in the contact zones of dowel-type joints of timber structures using expansive kits. To achieve this goal, a finite element model capable of determining the effect of using these kits on the global response of the joint has been prepared. For its development, different tools have been used to model the expansion process, the contact between the different parts of the joint, the compression pressures triggered by this contact, the resulting shear stresses caused by friction and, finally, the effect of all these circumstances on the overall performance of the joint, especially on the relationship between the applied load and the related displacement. The design of the model has been checked for correctness using experimental tests. The results obtained show that the use of expansive kits slightly improves the load-carrying capacity of the dowel through the rope effect.


Sign in / Sign up

Export Citation Format

Share Document