Numerical Study on Buckling Behaviour of Composite Cylindrical Shells under Axial Compressive Load with Asymmetric Meshing Technique

2013 ◽  
Vol 390 ◽  
pp. 198-203 ◽  
Author(s):  
Ziaul Rehman Tahir ◽  
Parthasarathi Mandal
Keyword(s):  
Shell Model ◽  
Numerical Study ◽  
Perturbation Technique ◽  
Compressive Load ◽  
Stable State ◽  
Buckling Load ◽  
Displacement Curve ◽  
Buckling Mode ◽  
Geometric Imperfection ◽  
Post Buckling

AMT is a perturbation technique to introduce disturbance in the model without changing geometry, boundary conditions or loading conditions. Asymmetric meshing technique is employed in the form of a band along circumferential direction of the shell model. The elements size in the band is reduced as compared with the rest of shell to produce asymmetry in the meshing and four magnitudes of asymmetry in meshing are used. Asymmetric meshing affects predicted buckling load, buckling mode shape and post-buckling behaviour. The reduction in the buckling load using AMT was observed to be about 20%. An isolated dimple formed near the bifurcation point and the size of which increased to reach a stable state in the post-buckling region. The load-displacement curve behaviour applying asymmetric meshing is quite similar to the curve obtained by introducing initial geometric imperfection in the shell model.

Buckling and Post-Buckling of Composite Shells with Asymmetric Meshing in Form of Axial Band in Numerical Model

2014 ◽  
Vol 1016 ◽  
pp. 790-796 ◽  
Author(s):  
Ziaul Rehman Tahir ◽  
Parthasarathi Mandal
Keyword(s):  
Numerical Model ◽  
Shell Model ◽  
Mode Shape ◽  
Axial Direction ◽  
Buckling Load ◽  
Displacement Curve ◽  
Buckling Mode ◽  
Geometric Imperfection ◽  
Post Buckling ◽  
Axial Band

Asymmetric meshing is a perturbation introduced in the numerical model without changing geometry, loading or boundary conditions. Asymmetric meshing is employed in the form of a band along axial direction of the shell model, the elements size in the axial band is reduced as compared with the rest of shell to produce asymmetry in the meshing and four amplitudes of asymmetry are used in a particular band. Asymmetric meshing affects predicted buckling load, buckling mode shape and post-buckling behaviour. The reduction in the buckling load using asymmetric meshing was observed to be about 18%, which depends mainly on area of asymmetric meshing and less on different magnitudes of asymmetry in the same area. The load-displacement curve behaviourusing asymmetric meshing technique is quite similar to the curve obtained by introducing geometric imperfection in the shell model.

Experimental and Numerical Study on Six- Point Bending Test of a Composite Stiffened Panel

2011 ◽  
Vol 328-330 ◽  
pp. 1309-1312
Author(s):  
Qiang Ye ◽  
San San Xiao ◽  
Pu Hui Chen
Keyword(s):  
Cohesive Zone Model ◽  
Numerical Study ◽  
Bending Test ◽  
Stiffened Panel ◽  
Zone Model ◽  
Buckling Mode ◽  
Stiffened Panels ◽  
Shell Elements ◽  
Composite Stiffened Panel ◽  
Post Buckling

A six-point bending test was presented to simulate skin/stiffener debonding under anti-symmetrical loading conditions. A novel rig was design via which the anti-symmetrical bending deformations can be forced on to the specimens. Experimental study on six-point bending test of composite stiffened panels of T700/QY8911 was done by using this rig. The tests are numerically analyzed using the finite element code ABAQUS, modeling the entire stiffened panel by shell elements, and investigating the progressive delamination by means of the cohesive zone model. The results of numerical analyses are compared to the experimental ones in terms of load-displacement curves and debonding positions between skin and stringer. The experimental and numerical resulits show that the anti-symmetrical bending deformation is the main factor which results in the asymmetrical propagation of the debonding between the skin and the stiffener. The failure mechanisms of the test are similar to the ones which induces skin/stiffener debonding during post-buckling in the anti-symmetrical buckling mode.

scholarly journals Post-Buckling Behaviour of laminated Cylindrical Panels with/without Cut-Outs

2019 ◽  
Vol 8 (3) ◽  
pp. 8026-8030
Keyword(s):  
Compressive Load ◽  
Laminated Composite ◽  
Cylindrical Panel ◽  
Buckling Load ◽  
Equilibrium Path ◽  
Cylindrical Panels ◽  
Post Buckling ◽  
The Impact ◽  
Generalized Finite Element ◽  
Composite Cylindrical Panel

Buckling and post-buckling analysis of isotropic and laminated composite cylindrical plates/panels under compressive load has been done by equilibrium path approach (arc-length technique). The impact of cut outs on buckling and post-buckling load of an isotropic and laminated composite cylindrical plates/panels has been assessed by utilizing summed up generalized finite element programming ANSYS. In post-buckling Eigen mode imperfection shape is picked for creating geometric undulations on cylindrical panels with/without circular cut-outs. The impact of the area and size of the cut out and furthermore the composite utilize point on the buckling load of laminated composite cylindrical panel is explored with simply supported boundary conditions. The post-buckling consequences of laminated cylindrical panels have been validated with existing appropriate writing (18) and are additionally stretched out for analysis of sheets/plates with cutouts. It has been seen that the as the curvature of the panel increases load bearing capacity is increasing irrespective of the material and with/without cut out.

scholarly journals Uncertainty in Loading and Control of an Active Column Critical to Buckling

2012 ◽  
Vol 19 (5) ◽  
pp. 929-937 ◽  
Author(s):  
G.C. Enss ◽  
R. Platz ◽  
H. Hanselka
Keyword(s):  
Compressive Load ◽  
Buckling Load ◽  
Buckling Mode ◽  
Design Constraint ◽  
Critical Buckling Load ◽  
Axial Compressive Load ◽  
Load Carrying ◽  
And Control ◽  
Important Design ◽  
Weight Structures

Buckling of load-carrying column structures is an important design constraint in light-weight structures as it may result in the collapse of an entire structure. When a column is loaded by an axial compressive load equal to its individual critical buckling load, a critically stable equilibrium occurs. When loaded above its critical buckling load, the passive column may buckle. If the actual loading during usage is not fully known, stability becomes highly uncertain.This paper presents an approach to control uncertainty in a slender flat column structure critical to buckling by actively stabilising the structure. The active stabilisation is based on controlling the first buckling mode by controlled counteracting lateral forces. This results in a bearable axial compressive load which can be theoretically almost three times higher than the actual critical buckling load of the considered system. Finally, the sensitivity of the presented system will be discussed for the design of an appropriate controller for stabilising the active column.

scholarly journals CFRP Origami Metamaterial with Tunable Buckling Loads: A Numerical Study

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 917
Author(s):  
Houyao Zhu ◽  
Shouyan Chen ◽  
Teng Shen ◽  
Ruikun Wang ◽  
Jie Liu
Keyword(s):  
Numerical Study ◽  
Buckling Load ◽  
Fe Modelling ◽  
Buckling Loads ◽  
Folding Angle ◽  
Mechanical Responses ◽  
Reinforced Plastic ◽  
Rate Of Increase ◽  
Practical Engineering ◽  
Identical Rate

Origami has played an increasingly central role in designing a broad range of novel structures due to its simple concept and its lightweight and extraordinary mechanical properties. Nonetheless, most of the research focuses on mechanical responses by using homogeneous materials and limited studies involving buckling loads. In this study, we have designed a carbon fiber reinforced plastic (CFRP) origami metamaterial based on the classical Miura sheet and composite material. The finite element (FE) modelling process’s accuracy is first proved by utilizing a CFRP plate that has an analytical solution of the buckling load. Based on the validated FE modelling process, we then thoroughly study the buckling resistance ability of the proposed CFRP origami metamaterial numerically by varying the folding angle, layer order, and material properties, finding that the buckling loads can be tuned to as large as approximately 2.5 times for mode 5 by altering the folding angle from 10° to 130°. With the identical rate of increase, the shear modulus has a more significant influence on the buckling load than Young’s modulus. Outcomes reported reveal that tunable buckling loads can be achieved in two ways, i.e., origami technique and the CFRP material with fruitful design freedoms. This study provides an easy way of merely adjusting and controlling the buckling load of lightweight structures for practical engineering.

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

Deformation Behavior Prediction of X80 Steel Line Pipe and Implication on High Strain Pipe Specification

2008 ◽  
Author(s):  
Hongyuan Chen ◽  
Lingkang Ji ◽  
Shaotao Gong ◽  
Huilin Gao
Keyword(s):  
Internal Pressure ◽  
Material Properties ◽  
High Strain ◽  
Behavior Prediction ◽  
Buckling Mode ◽  
Line Pipe ◽  
Geometric Imperfection ◽  
China National Petroleum Corporation ◽  
Scale Test ◽  
Pipe Size

The use of strain based design in pipeline technology has been widely discussed during the last decade for pipelines in harsh environment. In such cases pipelines should be designed based on strain criterion. Strain based design poses a number of challenges, particularly on pipe size and material properties. This paper presents preliminary studies on prediction of buckling strain and buckling mode for X80 high-strain line pipe by finite element methods based on full-scale test. The effects of several parameters such as internal pressure, material properties pipe size and geometric imperfection, were investigated to predict the critical strain for 48″ diameter line pipe under compression and pure bending with 12MPa internal pressure. Material parameters of a specification for high strain line pipe were analyzed to promote its application in the 2nd West-East pipeline of China National Petroleum Corporation.

Dynamic Buckling of Externally Pressurized Imperfect Cylindrical Shells

1975 ◽  
Vol 42 (2) ◽  
pp. 316-320 ◽  
Author(s):  
D. Lockhart ◽  
J. C. Amazigo
Keyword(s):  
Asymptotic Expression ◽  
Cylindrical Shells ◽  
Simple Relation ◽  
Dynamic Buckling ◽  
Fourier Component ◽  
Buckling Load ◽  
Buckling Mode ◽  
Geometric Imperfections ◽  
Circular Cylindrical Shells ◽  
Step Loading

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.

A numerical approach based on finite element method for the wrinkling analysis of dielectric elastomer membranes

2021 ◽  
pp. 1-37
Author(s):  
Guoyong Mao ◽  
Wei Hong ◽  
Martin Kaltenbrunner ◽  
Shaoxing Qu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thickness Distribution ◽  
Numerical Approach ◽  
Dielectric Elastomer ◽  
Equivalent Model ◽  
Maxwell Stress ◽  
Buckling Mode ◽  
Post Buckling ◽  
Element Method

Abstract Dielectric elastomer (DE) actuators are deformable capacitors capable of a muscle-like actuation when charged. When subjected to voltage, DE membranes coated with compliant electrodes may form wrinkles due to the Maxwell stress. Here, we develop a numerical approach based on the finite element method (FEM) to predict the morphology of wrinkled DE membranes mounted on a rigid frame. The approach includes two steps, I) pre-buckling and II) post-buckling. In step I, the first buckling mode of the DE membrane is investigated by substituting the Maxwell stress with thermal stress in the built-in function of the FEM platform SIMULIA Abaqus. In step II, we use this first buckling mode as an artificial geometric imperfection to conduct the post-buckling analysis. For this purpose, we develop an equivalent model to simulate the mechanical behavior of DEs. Based on our approach, the thickness distribution and the thinnest site of the wrinkled DE membranes subjected to voltage are investigated. The simulations reveal that the crests/troughs of the wrinkles are the thinnest sites around the center of the membrane and corroborate these findings experimentally. Finally, we successfully predict the wrinkles of DE membranes mounted on an isosceles right triangle frame with various sizes of wrinkles generated simultaneously. These results shed light on the fundamental understanding of wrinkled dielectric elastomers but may also trigger new applications such as programmable wrinkles for optical devices or their prevention in DE actuators.

Analysis of Nonlinear Buckling of a Long-Span Elliptic Paraboloid Suspended Dome Structure

2013 ◽  
Vol 639-640 ◽  
pp. 191-197 ◽  
Author(s):  
Zheng Rong Jiang ◽  
Kai Rong Shi ◽  
Xiao Nan Gao ◽  
Qing Jun Chen
Keyword(s):  
Single Layer ◽  
Buckling Mode ◽  
Nonlinear Buckling ◽  
Elliptic Paraboloid ◽  
Geometric Imperfection ◽  
Long Span ◽  
Initial Geometric Imperfection ◽  
Dome Structure ◽  
Unsymmetrical Loading ◽  
The Stability

The suspended dome structure, which is a new kind of hybrid spatial one composed of the upper single layer latticed shell and the lower cable-strut system, generally has smaller rise-to-span ratio, thus the overall stability is one of the key factors to the design of the structure. The nonlinear buckling behavior of an elliptic paraboloid suspended dome structure of span 110m80m is investigated by introducing geometric nonlinearity, initial geometric imperfection, material elastic-plasticity and half-span distribution of live loads. The study shows that the coefficient of stable bearing capacity usually is not minimal when the initial geometric imperfection configuration is taken as the first order buckling mode. The unsymmetrical loading distribution and the material nonlinearity might have significant effects on the coefficient. The structure is sensitive to the changes of initial geometric imperfection, and the consistent mode imperfection method is not fully applicable to the stability analysis of suspended dome structure.

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