Buckling and Nonlinear Analysis of Conoidal Shells

2016 ◽  
Author(s):  
Renata M. Soares ◽  
Paulo B. Gonçalves
Keyword(s):  
Natural Frequencies ◽  
Geometrically Nonlinear ◽  
Aesthetic Value ◽  
Shallow Shells ◽  
Practical Applications ◽  
Finite Element Software ◽  
Buckling Behavior ◽  
Quadratic Nonlinearities ◽  
Post Buckling ◽  
Shell Geometry

Slender shell structures described by ruled surfaces have been frequently used in civil engineering and, among these slender shells, conoidal shells are frequently favored as roofing units to cover large column-free areas due to their ease of construction, aesthetic value and structural efficiency. This work studies the nonlinear post-buckling behavior of a conoidal shell, using commercial finite element software ABAQUS®. The problem is geometrically nonlinear due to the shell strong geometric nonlinearity, especially in the case of shallow shells used in practical applications where quadratic nonlinearities play an important role. A detailed parametric analysis is conducted to show the influence of the shell geometry on the buckling loads and natural frequencies and, especially, on the nonlinear post-buckling behavior and stability.

Buckling and Postbuckling Behavior of Clamped Shallow Spherical Shells Under Axisymmetric Ring Loads

1971 ◽  
Vol 38 (4) ◽  
pp. 996-1002 ◽  
Author(s):  
N. Akkas ◽  
N. R. Bauld
Keyword(s):  
Numerical Study ◽  
Postbuckling Behavior ◽  
Spherical Shells ◽  
Concentrated Load ◽  
Fixed Ring ◽  
Buckling Behavior ◽  
Load Carrying ◽  
Post Buckling ◽  
Shell Parameter ◽  
Shell Geometry

This paper presents the results of a numerical study of the buckling and initial post-buckling behavior of clamped shallow spherical shells under axisymmetric ring loads. This behavior is studied for a cap with fixed geometry when the location of the ring load is allowed to vary from the equivalent of a concentrated load at the apex to a location near the midpoint of the shell base radius, and for a fixed ring load location when the shell geometry is allowed to vary. It is found in both studies that a significant range of the geometric shell parameter λ exists such that buckling is accompanied by a loss in load-carrying capacity.

Fiber Orientation Effect in the Dynamic Buckling of Debonded Regions in Laterally Loaded FRP Strengthened Walls

2014 ◽  
Vol 624 ◽  
pp. 470-477 ◽  
Author(s):  
Dvir Elmalich ◽  
Oded Rabinovitch
Keyword(s):  
Fiber Orientation ◽  
Numerical Approach ◽  
Shear Loading ◽  
Element Formulation ◽  
Geometrically Nonlinear ◽  
Nonlinear Dynamic Response ◽  
Critical Displacement ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Laterally Loaded

This paper studies the effect of lamination and fiber orientation on the geometrically nonlinear dynamic response of debonded regions in walls strengthened with FRP. The paper adopts an analytical/numerical approach and uses a specially tailored finite element formulation for the layered structure. By means of this analytical/numerical tool, two strengthening layouts for a wall segment subjected to a dynamic shear loading are compared. In the first layout, the fibers are oriented along the width and height of the segment and in the second one, they are oriented along its diagonals. The analysis reveals that the two layouts are involved with significantly different critical points and significantly different dynamic post-buckling behaviors. Specifically, it shows that the diagonal layout, which better serves the shear loading scenario, is involved with a much smaller critical displacement and a dynamic post-buckling behavior that is governed by the stiffer compressed and tensed diagonals.

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.

scholarly journals Post-buckling behavior estimation of rigidly supported cylindrical composite panels in case shear

2021 ◽  
Vol 2094 (4) ◽  
pp. 042078
Author(s):  
O V Mitrofanov ◽  
M Osman
Keyword(s):  
Linear Problem ◽  
Nonlinear Behavior ◽  
Cylindrical Panel ◽  
Geometrically Nonlinear ◽  
Rigid Support ◽  
Buckling Behavior ◽  
Nonlinear Stress ◽  
Cylindrical Panels ◽  
Post Buckling ◽  
Composite Cylindrical Panel

Abstract We present the solution of the geometrically nonlinear problem of the shear-critical behavior of a thin composite cylindrical panel of small curvature of orthotropic structure. The obtained solution considers the conditions of all-round rigid support. The expression for determining the membrane stresses arising in the supercritical state is given. When considering a linear problem, expressions for determining the critical shear flow are given. A method for determining the nonlinear stress-strain state in the overcritical state for a given thickness and stacking of an orthotropic panel is presented. The obtained solutions can be used in the design of load-bearing cylindrical panels, as well as in the analysis of geometrically nonlinear behavior of defects such as delaminations.

The Postbuckling Behavior of Planar Elastica Constrained by a Deformable Wall

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Shmuel Katz ◽  
Sefi Givli
Keyword(s):  
Mode Switching ◽  
Careful Examination ◽  
Postbuckling Behavior ◽  
Contact Conditions ◽  
Practical Applications ◽  
Buckling Behavior ◽  
Wide Range ◽  
Compliant Wall ◽  
Post Buckling ◽  
The Mathematical Model

Attributed to its significance in a wide range of practical applications, the post-buckling behavior of a beam with lateral constraints has drawn much attention in the last few decades. Despite the fact that, in reality, the lateral constraints are often flexible or deformable, vast majority of studies have considered fixed and rigid lateral constraints. In this paper, we make a step toward bridging this gap by studying the post-buckling behavior of a planar beam that is laterally constrained by a deformable wall. Unfortunately, the interaction with a compliant wall prevents derivation of closed-form analytical solutions. Nevertheless, careful examination of the governing equations of a simplified model reveals general properties of the solution, and let us identify the key features that govern the behavior. Specifically, we construct universal “solution maps” that do not depend on the mode number and enable simple and easy prediction of the contact conditions and of the mode-switching force (the force at which the system undergoes instantaneous transition from one equilibrium configuration (or mode) to another). The predictions of the mathematical model are validated against finite element (FE) simulations.

Buckling Behavior of Tire Breaker Structure

1983 ◽  
Vol 11 (1) ◽  
pp. 3-19
Author(s):  
T. Akasaka ◽  
S. Yamazaki ◽  
K. Asano
Keyword(s):  
Elastic Foundation ◽  
Elastic Moduli ◽  
Wave Length ◽  
Bending Moment ◽  
Experimental Results ◽  
Automobile Tire ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Steel Cord ◽  
Interlaminar Shear

Abstract The buckled wave length and the critical in-plane bending moment of laminated long composite strips of cord-reinforced rubber sheets on an elastic foundation is analyzed by Galerkin's method, with consideration of interlaminar shear deformation. An approximate formula for the wave length is given in terms of cord angle, elastic moduli of the constituent rubber and steel cord, and several structural dimensions. The calculated wave length for a 165SR13 automobile tire with steel breakers (belts) was very close to experimental results. An additional study was then conducted on the post-buckling behavior of a laminated biased composite beam on an elastic foundation. This beam is subjected to axial compression. The calculated relationship between the buckled wave rise and the compressive membrane force also agreed well with experimental results.

THE SUPPORT BONDS RIGIDITY INFLUENCES ON THE CARRYING CAPACITY REDUCTION OF THE SHALLOW SHELLS ON A RECTANGULAR PLAN

2020 ◽  
Vol 92 (6) ◽  
pp. 3-12
Author(s):  
A.G. KOLESNIKOV ◽  
Keyword(s):  
Variable Thickness ◽  
Carrying Capacity ◽  
Geometric Nonlinearity ◽  
Progressive Collapse ◽  
Geometrically Nonlinear ◽  
Loss Of Stability ◽  
Shallow Shells ◽  
Capacity Reduction ◽  
Internal Forces ◽  
Hinged Support

Geometric nonlinearity shallow shells on a square and rectangular plan with constant and variable thickness are considered. Loss of stability of a structure due to a decrease in the rigidity of one of the support (transition from fixed support to hinged support) is considered. The Bubnov-Galerkin method is used to solve differential equations of shallow geometrically nonlinear shells. The Vlasov's beam functions are used for approximating. The use of dimensionless quantities makes it possible to repeat the calculations and obtain similar dependences. The graphs are given that make it possible to assess the reduction in the critical load in the shell at each stage of reducing the rigidity of the support and to predict the further behavior of the structure. Regularities of changes in internal forces for various types of structure support are shown. Conclusions are made about the necessary design solutions to prevent the progressive collapse of the shell due to a decrease in the rigidity of one of the supports.

Appraisal of Allowable Loads by Simplified Rules

1986 ◽  
Vol 108 (2) ◽  
pp. 131-137
Author(s):  
D. Moulin
Keyword(s):  
Experimental Investigation ◽  
Plastic Region ◽  
Thin Structures ◽  
Geometric Imperfections ◽  
Buckling Behavior ◽  
Simplified Method ◽  
Post Buckling ◽  
Initial Geometric Imperfections ◽  
Fast Breeder Reactors ◽  
Breeder Reactors

This paper presents a simplified method to analyze the buckling of thin structures like those of Liquid Metal Fast Breeder Reactors (LMFBR). The method is very similar to those used for the buckling of beams and columns with initial geometric imperfections, buckling in the plastic region. Special attention is paid to the strain hardening of material involved and to possible unstable post-buckling behavior. The analytical method uses elastic calculations and diagrams that account for various initial geometric defects. An application of the method is given. A comparison is made with an experimental investigation concerning a representative LMFBR component.

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