Local Buckling of Outstands in Stiffened Plates

1976 ◽  
Vol 27 (4) ◽  
pp. 277-291 ◽  
Author(s):  
W C Fok ◽  
J Rhodes ◽  
A C Walker
Keyword(s):  
Local Buckling ◽  
Strain Range ◽  
Maximum Load ◽  
Simple Expression ◽  
Stiffened Plates ◽  
Elastic Buckling ◽  
Analytical Prediction ◽  
Imperfection Sensitivity ◽  
Post Buckling ◽  
Overall Buckling

SummaryThis paper reports on an investigation of the effect of local elastic buckling of stiffener outstands on the overall behaviour of stiffened plates. A simplified mathematical model has been developed, based on the post-buckling analysis of the stiffener, and gives a simple expression which indicates that, for the plate geometry investigated, the maximum load carried varies asymptotically between the local critical load of the stiffener and a reduced Euler load. Also, there is a marked imperfection sensitivity arising from the interaction of the local and overall buckling modes. Experiments were carried out to confirm the analytical prediction for the elastic buckling behaviour of the stiffened plates. The models were constructed of Araldite, to allow large deformation within the elastic strain range. Experimental results showed very good agreement with the theory.

Interactive Buckling of Sandwich Plates Under Compression

2001 ◽  
Author(s):  
Srinivasan Sridharan ◽  
Kim Sunjung ◽  
Sami I. El-Sayed
Keyword(s):  
Maximum Load ◽  
Core Material ◽  
Local Mode ◽  
Modal Interaction ◽  
Compressive Behavior ◽  
Imperfection Sensitivity ◽  
The Core ◽  
Post Buckling ◽  
Overall Buckling ◽  
Interactive Buckling

Abstract Compressive behavior of two classes of “sandwich” structures is investigated. These structures have for their principal load bearing components two relatively stiff parallel horizontal sheets which are interconnected in one of the following ways: (i) by a highly compliant core material such as foam, or (ii) a set of discrete stiffeners connecting the parallel (top and bottom) sheets. In case (i), the structure can buckle in either a local mode in which the core and the facing bend together or a wrinkling mode in which the facing sheet undergoes severe bending with the core subjected to deformation in the transverse plane. It is found that these plates have neither post buckling stiffness nor do they exhibit any imperfection-sensitivity. In case (ii) the point of principal interest is the interaction of local and overall buckling. For the case of coincident local and overall buckling, it is found that 30% reduction in the maximum load can occur for modest levels of imperfections as a result of modal interaction.

scholarly journals Post-buckling of a pressured biopolymer spherical shell with the mode interaction

2018 ◽  
Vol 474 (2211) ◽  
pp. 20170834 ◽  
Author(s):  
Lei Zhang ◽  
C. Q. Ru
Keyword(s):  
Spherical Shell ◽  
Maximum Load ◽  
Ultrasound Contrast Agents ◽  
Mode Interaction ◽  
Imperfection Sensitivity ◽  
Spherical Shells ◽  
Viral Capsids ◽  
Axisymmetric Mode ◽  
Post Buckling ◽  
Relative Errors

Imperfection sensitivity is essential for mechanical behaviour of biopolymer shells characterized by high geometric heterogeneity. The present work studies initial post-buckling and imperfection sensitivity of a pressured biopolymer spherical shell based on non-axisymmetric buckling modes and associated mode interaction. Our results indicate that for biopolymer spherical shells with moderate radius-to-thickness ratio (say, less than 30) and smaller effective bending thickness (say, less than 0.2 times average shell thickness), the imperfection sensitivity predicted based on the axisymmetric mode without the mode interaction is close to the present results based on non-axisymmetric modes with the mode interaction with a small (typically, less than 10%) relative errors. However, for biopolymer spherical shells with larger effective bending thickness, the maximum load an imperfect shell can sustain predicted by the present non-axisymmetric analysis can be significantly (typically, around 30%) lower than those predicted based on the axisymmetric mode without the mode interaction. In such cases, a more accurate non-axisymmetric analysis with the mode interaction, as given in the present work, is required for imperfection sensitivity of pressured buckling of biopolymer spherical shells. Finally, the implications of the present study to two specific types of biopolymer spherical shells (viral capsids and ultrasound contrast agents) are discussed.

Model studies of the elastic buckling of a stiffened plate

1976 ◽  
Vol 11 (3) ◽  
pp. 137-143 ◽  
Author(s):  
J D Tulk ◽  
A C Walker
Keyword(s):  
Strain Range ◽  
Scale Model ◽  
Small Scale ◽  
Elastic Buckling ◽  
Engineering Structures ◽  
Model Studies ◽  
Plate Elements ◽  
Scale Models ◽  
Load Carrying ◽  
Post Buckling

The paper reports on an experimental investigation of the elastic buckling behaviour of a small-scale model of a stiffened plane. The model was made from epoxy resin to allow large buckle deflections within the elastic strain range. These tests are part of a programme aimed at proving the feasibility of using small-scale models to elucidate the behaviour of large stiffened plates such as are used in marine or civil engineering structures. It is shown for the geometry examined here that, although the component stringer and plate elements of the panel would individually exhibit stable post-buckling, together they interact to give unstable behaviour. The effects of imperfections are systematically studied and it is shown that the load-carrying capacity of such a structural configuration is sensitive to initial geometric deformations. A simple mathematical analysis is developed which indicates the parameters governing the physical problem and which could form the basis for future rational studies of the level of imperfections at which sensitivity may be considered slight.

Effect of Core Plasticity on the Post-Buckling Behavior of Debonded Sandwich Beams

2000 ◽  
Author(s):  
Bhavani V. Sankar ◽  
Manickam Narayanan ◽  
Abhinav Sharma
Keyword(s):  
Plastic Material ◽  
Maximum Load ◽  
Face Sheet ◽  
Compression Tests ◽  
Element Analysis ◽  
The Core ◽  
Perfectly Plastic ◽  
The Face ◽  
Post Buckling ◽  
Elastic Perfectly Plastic

Abstract Nonlinear finite element analysis was used to simulate compression tests on sandwich composites containing debonded face sheets. The core was modeled as an elastic-perfectly-plastic material, and the face-sheet as elastic isotropic. The effects of core plasticity, face-sheet and core thickness, and debond length on the maximum load the beam can carry were studied. The results indicate that the core plasticity is an important factor that determines the maximum load.

Elastic Buckling of Stiffened Plates

1972 ◽  
Vol 98 (11) ◽  
pp. 2641-2645
Author(s):  
Charles Culver ◽  
Clive Dym
Keyword(s):  
Stiffened Plates ◽  
Elastic Buckling

Comparative Design of Orthogonally Stiffened Plates for Production and Structural Integrity—Part 1: Size Optimization

1994 ◽  
Vol 10 (03) ◽  
pp. 146-155
Author(s):  
Nicholas Hatzidakis ◽  
Michael M. Bernitsas
Keyword(s):  
Structural Integrity ◽  
Plate Theory ◽  
Plate Thickness ◽  
Stiffened Plates ◽  
Size Optimization ◽  
Element Analysis ◽  
Total Cost ◽  
Plate Buckling ◽  
Design Variables ◽  
Overall Buckling

Five alternative configurations of orthogonally stiffened plates are compared in order to identify the total cost optimum design including material and fabrication cost. Size optimization is performed within the limitations of structural component standardization for each of the five alternatives. The five optimal structures are then compared in terms of weight, fabrication, and total cost. Discrete sizing optimization is performed in this paper with two design variables, i.e., plate thickness and standardized beam cross section. Constraints are imposed on secondary and tertiary stresses computed by finite-element analysis (FEA); and on primary stresses to prevent plate buckling, stiffener tripping, and overall buckling. Confidence is established in the FEA results by making comparisons with FEA results using the effective breadth method and orthotropic plate theory. Producibility constraints dictated by standardization in shipyard practice are imposed as well.

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