Nodal Lines for Long Plates in Combined Shear and Compression with Sinusoidal Edge Rotations

1969 ◽  
Vol 20 (1) ◽  
pp. 1-16 ◽  
Author(s):  
W. H. Wittrick ◽  
P. L. V. Curzon
Keyword(s):  
Local Buckling ◽  
Sandwich Panels ◽  
Longitudinal Direction ◽  
Longitudinal Compression ◽  
Buckling Mode ◽  
Stiffened Panels ◽  
Nodal Lines ◽  
Integrally Stiffened Panels ◽  
The Individual

SummaryThe work described in this paper forms part of a programme on the local buckling of long thin flat-walled structures, such as integrally stiffened panels or corrugated core sandwich panels, with the individual flats subjected to combined longitudinal compression and shear. When buckling occurs, the line junctions between adjoining flats remain straight, but rotations occur about the junctions. These rotations vary sinusoidally in the longitudinal direction but, because of the shear, the rotations at the two edges of an individual flat are out of phase with each other. In order to picture the buckling mode it is essential to have at least a qualitative idea of the shape of the nodal lines in the flats. The analysis of this paper is entirely concerned with this problem.

Stability Functions for the Local Buckling of Thin Flat-Walled Structures with the Walls in Combined Shear and Compression

1968 ◽  
Vol 19 (4) ◽  
pp. 327-351 ◽  
Author(s):  
W. H. Wittrick ◽  
P. L. V. Curzon
Keyword(s):  
Pure Shear ◽  
Local Buckling ◽  
Sandwich Panels ◽  
The Other ◽  
Longitudinal Compression ◽  
Stiffened Panels ◽  
Stability Functions ◽  
Integrally Stiffened Panels ◽  
The Individual ◽  
Phase Differences

SummaryThis paper is concerned with the local buckling of long thin flat-walled structures, such as integrally stiffened panels or corrugated core sandwich panels, loaded in such a way that the individual flats are in combined uniform longitudinal compression and shear. When buckling occurs the line junctions between adjoining flats remain straight, and the flats are subjected on their long edges to sinusoidally varying edge moments. These produce sinusoidally varying edge rotations which, when shear is present, are in general out of phase with each other and with the moments. Relations between the edge moments and rotations are obtained in terms of two stability functions, one of which is real and the other complex, to take account of phase differences. Explicit expressions are derived for these stability functions and tables are included, giving their values for the case of pure shear.

A Unified Approach to the Initial Buckling of Stiffened Panels in Compression

1968 ◽  
Vol 19 (3) ◽  
pp. 265-283 ◽  
Author(s):  
W. H. Wittrick
Keyword(s):  
Theory Of Elasticity ◽  
Unified Approach ◽  
Buckling Mode ◽  
Uniform Compression ◽  
Determinantal Equation ◽  
Stiffened Panels ◽  
Stiffness Matrices ◽  
Out Of Plane ◽  
The Individual

SummaryThis paper provides the basis for a very general approach to the determination of initial buckling stresses of long stiffened panels in uniform longitudinal compression. The panels are assumed to consist of a series of long flat strips, rigidly connected together at their edges, as in panels with top-hat or Z-section stringers, or in sandwich panels with corrugated cores. Whatever the buckling mode, the individual flats are subjected, just after buckling, to sinusoidally varying systems of both out-of-plane and in-plane edge forces and moments, superimposed on the basic state of uniform compression. The stiffness matrices corresponding to these sinusoidal edge loads are derived, taking account of the destabilising effect of the basic longitudinal compressive stress, not only in the out-of-plane but also in the in-plane deformations. For the latter purpose a non-linear theory of elasticity is used. The application of these stiffness matrices to specific panels is briefly described. All possible modes are incorporated within one determinantal equation. For panels with identical stiffeners spaced at equal intervals, the order of the determinant is independent of the number of stiffeners.

Prediction of compression buckling load and buckling mode of hat-stiffened panels using artificial neural network

2021 ◽  
Vol 242 ◽  
pp. 112275
Author(s):  
Zhenya Sun ◽  
Zhenkun Lei ◽  
Ruixiang Bai ◽  
Hao Jiang ◽  
Jianchao Zou ◽  
...  
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Buckling Load ◽  
Buckling Mode ◽  
Stiffened Panels ◽  
Artificial Neural

ELASTIC BUCKLING OF THIN-WALLED CIRCULAR TUBES CONTAINING AN ELASTIC INFILL

2006 ◽  
Vol 06 (04) ◽  
pp. 457-474 ◽  
Author(s):  
M. A. BRADFORD ◽  
A. ROUFEGARINEJAD ◽  
Z. VRCELJ
Keyword(s):  
Axial Compression ◽  
A Priori ◽  
Local Buckling ◽  
Steel Tube ◽  
Transcendental Equation ◽  
Buckling Mode ◽  
Buckling Stress ◽  
Elastic Tubes ◽  
Thin Walled ◽  
Energy Formulation

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.

Local Buckling and Mode Switching in the Optimum Design of Stiffened Panels

AIAA Journal ◽  
2008 ◽  
Vol 46 (6) ◽  
pp. 1542-1548 ◽  
Author(s):  
Peyman Khosravi ◽  
Ramin Sedaghati
Keyword(s):  
Optimum Design ◽  
Local Buckling ◽  
Mode Switching ◽  
Stiffened Panels

scholarly journals Effects of plies orientations and initial geometric imperfections on buckling strength of a composite stiffened panel

2018 ◽  
Vol 191 ◽  
pp. 00008
Author(s):  
Ikram Feddal ◽  
Abdellatif Khamlichi ◽  
Koutaiba Ameziane
Keyword(s):  
Stiffened Panel ◽  
Buckling Mode ◽  
Element Analysis ◽  
Geometric Imperfections ◽  
Stiffened Panels ◽  
Specific Strength ◽  
Euler Buckling ◽  
Buckling Behavior ◽  
Composite Stiffened Panel ◽  
Strength And Stiffness

The use of composite stiffened panels is common in several activities such as aerospace, marine and civil engineering. The biggest advantage of the composite materials is their high specific strength and stiffness ratios, coupled with weight reduction compared to conventional materials. However, any structural system may reach its limit and buckle under extreme circumstances by a progressive local failure of components. Moreover, stiffened panels are usually assembled from elementary parts. This affects the geometric as well as the material properties resulting in a considerable sensitivity to buckling phenomenon. In this work, the buckling behavior of a composite stiffened panel made from carbon Epoxy Prepregs is studied by using the finite element analysis under Abaqus software package. Different plies orientations sets were considered. The initial distributed geometric imperfections were modeled by means of the first Euler buckling mode. The nonlinear Riks method of analysis provided by Abaqus was applied. This method enables to predict more consistently unstable geometrically nonlinear induced collapse of a structure by detecting potential limit points during the loading history. It was found that plies orientations of the composite and the presence of geometric imperfections have huge influence on the strength resistance.

The development of design guidelines for integrally stiffened panels under compression using surrogate modelling

2017 ◽  
Vol 233 (3) ◽  
pp. 779-792
Author(s):  
Morteza Dezyani ◽  
Shahram Yousefi ◽  
Hossein Dalayeli ◽  
Hamid Frrokhfal
Keyword(s):  
Finite Element ◽  
Global Optimum ◽  
Initial Guess ◽  
Design Guidelines ◽  
Programming Algorithm ◽  
Preliminary Design ◽  
Finite Element Analyses ◽  
Surrogate Modelling ◽  
Stiffened Panels ◽  
Integrally Stiffened Panels

Preliminary design of stiffened compression panels used in aerospace structures is commonly based on the routine analytical and semi-empirical equations. Empirical charts are used for obtaining an initial guess to start the preliminary design process. In this paper, preliminary design guidelines for stiffened compression panels are developed based on the non-linear finite element analyses. Meanwhile, the process of design and optimization of the stiffened compression panels are carried out. Modelling phase is based on the finite element simulations of the structure. The surrogate modelling technique is employed to reduce the number of finite element analyses. An efficient technique is developed to find the global optimum of the surrogate model using sequential quadratic programming algorithm. The proposed approach is applied to two types of integrally stiffened panels. The final results are extracted as practical design guidelines which are suitable for preliminary design phase.

Advanced Closed-Form Ultimate Strength Formulation for Ships

2001 ◽  
Vol 45 (02) ◽  
pp. 111-132 ◽  
Author(s):  
Jeom Kee Paik ◽  
Owen F. Hughes ◽  
Alaa E. Mansour
Keyword(s):  
Ultimate Strength ◽  
Structural Damage ◽  
Lateral Pressure ◽  
Local Buckling ◽  
Bending Moment ◽  
Stiffened Panels ◽  
Initial Imperfections ◽  
Ship Hulls ◽  
Collapse Column ◽  
Side Shell

The aim of this paper is to develop an advanced ultimate strength formulation for ship hulls under vertical bending moment. Since the overall failure of a ship hull is normally governed by buckling and plastic collapse of the deck, bottom, and sometimes the side shell stiffened panels, it is of crucial importance to accurately calculate the ultimate strength of stiffened panels in deck, bottom and side shell for more advanced ultimate strength analyses. In this regard, the developed formulation is designed to be more sophisticated than previous simplified theoretical methods for calculating the ultimate strength of stiffened panels under combined axial load, in-plane bending and lateral pressure. Fabrication-related initial imperfections (initial deflections and residual stresses) and potential structural damage related to corrosion, collision, or grounding are included in the panel ultimate strength calculations as parameters of influence. All possible collapse modes involved in collapse of stiffened panels, including overall buckling collapse, column or beam-column type collapse (plate or stiffener induced collapse), tripping of stiffeners and local buckling of stiffener web, are considered. As illustrative examples, the paper investigates and discusses the sensitivity of parameters such as lateral pressure, fabrication-related initial imperfections, corrosion, collision and grounding damage on the ultimate strength of a typical Cape size bulk carrier hull under vertical bending.

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