GBT FORMULATION TO ANALYZE THE BUCKLING BEHAVIOR OF THIN-WALLED MEMBERS SUBJECTED TO NON-UNIFORM BENDING

2007 ◽  
Vol 07 (01) ◽  
pp. 23-54 ◽  
Author(s):  
RUI BEBIANO ◽  
NUNO SILVESTRE ◽  
DINAR CAMOTIM
Keyword(s):  
Finite Element ◽  
Major Axis ◽  
Shear Stresses ◽  
Longitudinal Stress ◽  
Stress Gradients ◽  
Stiffness Reduction ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Thin Walled ◽  
Uniformly Distributed Loads

In this paper, one investigates the local-plate, distortional and global buckling behavior of thin-walled steel beams subjected to non-uniform bending moment diagrams, i.e. under the presence of longitudinal stress gradients. One begins by deriving a novel formulation based on Generalized Beam Theory (GBT), which (i) can handle beams with arbitrary open cross-sections and (ii) incorporates all the effects stemming from the presence of longitudinally varying stress distributions. This formulation is numerically implemented by means of the finite element method: one (i) develops a GBT-based beam finite element, which accounts for the stiffness reduction associated to applied longitudinal stresses with linear, quadratic and cubic variation, as well as to the ensuing shear stresses, and (ii) addresses the derivation of the equilibrium equation system that needs to be solved in the context of a GBT buckling analysis. Then, in order to illustrate the application and capabilities of the proposed GBT-based formulation and finite element implementation, one presents and discusses numerical results concerning (i) rectangular plates under longitudinally varying stresses and pure shear, (ii) I-section cantilevers subjected to uniform major axis bending, tip point loads and uniformly distributed loads, and (iii) simply supported lipped channel beams subjected to uniform major axis bending, mid-span point loads and uniformly distributed loads — by taking full advantage of the GBT modal nature, one is able to acquire an in-depth understanding on the influence of the longitudinal stress gradients and shear stresses on the beam local and global buckling behavior. For validation purposes, the GBT results are compared with values either (i) yielded by shell finite element analyses, performed in the code ANSYS, or (ii) reported in the literature. Finally, the computational efficiency of the proposed GBT-based beam finite element is briefly assessed.

GBT-BASED BUCKLING ANALYSIS OF THIN- WALLED STEEL FRAMES WITH ARBITRARY LOADING AND SUPPORT CONDITIONS

2010 ◽  
Vol 10 (03) ◽  
pp. 363-385 ◽  
Author(s):  
CILMAR BASAGLIA ◽  
DINAR CAMOTIM ◽  
NUNO SILVESTRE
Keyword(s):  
Finite Element ◽  
Beam Theory ◽  
Mode Shapes ◽  
Shear Stresses ◽  
Transverse Beam ◽  
Space Frames ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Thin Walled ◽  
Support Conditions

This paper is concerned with the development and application of a Generalized Beam Theory (GBT) formulation to analyse the local and global buckling behavior of thin-walled steel plane and space frames with arbitrary loadings and various support conditions. This formulation takes into account the geometrical effects stemming from the presence of longitudinal normal stress gradients and also the ensuing pre-buckling shear stresses. Following a description of the main concepts and procedures involved in determining the finite element and frame linear and geometric stiffness matrices (incorporating the influence of joints, applied loading and support conditions), one presents and discusses some numerical results concerning the local and global buckling behavior of (i) simple "L-shaped" frames and (ii) space frames formed by two symmetrical portal frames joined through a transverse beam. For validation purposes, the GBT-based results are compared with those obtained by rigorous shell finite element analyses using ANSYS. An excellent correlation, for both the critical buckling loads and mode shapes, is found in all cases.

Buckling of Composite Thin-Walled Members

2006 ◽  
Vol 326-328 ◽  
pp. 1733-1736 ◽  
Author(s):  
Seung Sik Lee ◽  
Soon Jong Yoon ◽  
Sung Yong Back
Keyword(s):  
Civil Engineering ◽  
Glass Fibers ◽  
Engineering Application ◽  
Maintenance Cost ◽  
Construction Time ◽  
Specific Strength ◽  
High Specific Strength ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Thin Walled

The use of pultruded fiber reinforced polymeric (FRP) members in civil engineering applications can greatly reduce construction time and maintenance cost of structures, because pultruded members have high specific strength and excellent corrosion resistance compared to steel and concrete. Pultruded members for civil engineering application are mostly made of a polymeric resin system reinforced with E-glass fibers and, as a result, they have low elastic moduli. Therefore, stability is an important issue in the design of pultruded members. In this paper, the results of an experimental investigation into the global buckling behavior of pultruded thin-walled members subjected to axial compression are presented. The analytical solutions are validated through a comparison with the results of FE analysis as well as the experimental results.

Designing Hierarchical IsoTruss Column Based on Controlling Multi-Buckling Behaviors

2021 ◽  
Author(s):  
Changliang Lai ◽  
Qianqian Sui ◽  
Hualin Fan
Keyword(s):  
Finite Element ◽  
Parametric Design ◽  
Local Buckling ◽  
Fe Model ◽  
The Finite Element Method ◽  
Buckling Modes ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Buckling Failure ◽  
Theoretical Analyses

To develop large-span but ultralight lattice truss columns, a hierarchical IsoTruss column (HITC) was proposed. The multi-buckling behavior of the axially compressed HITC was analyzed by the finite element method (FEM) using a parametric approach in the framework of ANSYS parametric design language (APDL). It was demonstrated that the program enables efficient generation of the finite element (FE) model, while facilitating the parametric design of the HITC. Using this program, the effects of helical angles and brace angles on the buckling behavior of the HITC were investigated. Depending on the helical angles and brace angles, the HITCs mainly have three buckling modes: the global buckling, the first-order local buckling and the second-order local buckling. Theoretical multi-buckling models were established to predict the critical buckling loads. Buckling failure maps based on the theoretical analyses were also developed, which can be useful in preliminary design of such structures.

Analysis of Delaminated Composite Plates

2013 ◽  
Vol 686 ◽  
pp. 104-108
Author(s):  
Ali Mahieddine ◽  
Mohammed Ouali
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Composite Beam ◽  
Composite Structures ◽  
Failure Modes ◽  
Laminated Composite ◽  
Composite Plates ◽  
Published Data ◽  
Shear Stresses ◽  
Buckling Behavior

A mathematical model for plates with partially delaminated layers is presented to investigate their behavior. In this formulation account is taken of lateral strains. The principal advantage of the element is that it allows the modeling of delamination anywhere in the structure. The region without delamination is modeled to carry constant peel and shear stresses; while the region with delamination is modeled by assuming that there is no peel and shear stress transfer between the top and bottom layers. Numerical results of the present model are presented and its performance is evaluated for static problems. Laminated beams and plates are often used as primary load-carrying structures. However, the mechanical properties of composite materials may degrade severely in the presence of damage. One of the common types of damage modes in laminated composites is delamination. The presence of delamination is one of the most prevalent life-limiting failure modes in laminated composite structures. Many researchers had been studying the effect of delamination. Wee and Boay [1] developed an analytical model to predict the critical load of a delaminated composite laminated beam. Lee et al. [2] investigated the buckling behavior of the beam plate with multiple delaminations under compression. Kapania and Wolfe [3] examined the buckling behavior of a beam plate with two delaminations of equal length. Wang et al. [4] improved the analytical solution by including the coupling between the flexural and axial vibrations of the delaminated sub-laminates. Lee et al. [5] studied a composite beam with arbitrary lateral and longitudinal multiple delamination. Finite-element methods have been developed using the layerwise theory by Kim et al. [6]. Tan and Tong [7] developed a dynamic analytical model for the identification of delamination embedded in a laminated composite beam. To investigate the effects of delamination of a plate layers, a finite-element model is developed. Both displacement continuity and force equilibrium conditions are imposed between the regions with and without delamination. The accuracy of the approach is verified by comparing results with previously published data.

The Stiffness of a Two-Cell Anisotropic Tube

1981 ◽  
Vol 32 (4) ◽  
pp. 338-353 ◽  
Author(s):  
E.H. Mansfield
Keyword(s):  
Single Cell ◽  
Fibre Composite ◽  
Cylindrical Tube ◽  
Shear Stresses ◽  
Longitudinal Stress ◽  
Bearing Material ◽  
Principal Moments Of Inertia ◽  
Principal Axes ◽  
Tension Axis ◽  
Thin Walled

SummaryAn analysis is made of the general two-cell thin-walled cylindrical tube subjected to longitudinal tension, bending and torsion. The walls of the tube may be of fibre composite with an asymmetric lay-up resulting in a coupling between direct and shear stresses and strains. The two-cell tube differs from the single-cell tube in that the tension axis and the principal axes of bending are not necessarily aligned to the c.g. and the principal moments of inertia of the longitudinal stress bearing material.

scholarly journals Parametric Study on Buckling Behavior of Aluminum Alloy Thin-Walled Lipped Channel Beam with Perforations Subjected to Combined Loading

2021 ◽  
Vol 39 (1A) ◽  
pp. 89-103
Author(s):  
Dalya S. Khazaal ◽  
Hussein M. AL-Khafaji ◽  
Imad A. Abdulsahib
Keyword(s):  
Finite Element ◽  
Experimental Tests ◽  
Combined Loading ◽  
Buckling Strength ◽  
Buckling Behavior ◽  
Element Simulation ◽  
Spacing Ratio ◽  
Opening Ratio ◽  
Thin Walled ◽  
Channel Beam

The objective of the research presented in this paper is to investigate the buckling behavior of a perforated thin-walled lipped channel beam subjected to combined load. A nonlinear finite element method was used to analyze the buckling behavior of the beam. Experimental tests were made to validate the finite element simulation. Three factors with three levels for each factor were chosen to examine their influence on the buckling behavior of the beam and these factors are: the shape of holes, opening ratio  and the spacing ratio of. The finite elements outcome was analyzed by using Taguchi method to identify the best set of three-parameter combinations for optimum critical buckling load. The analysis of variance technique (ANOVA) was implemented to determine the contribution of each parameter on buckling strength. Results showed that the mode of buckling failure of the perforated beam is lateral-torsional buckling and the hexagonal hole shape, =1.7 and = 1.3 were the best combination of parameters that gives the best buckling strength. The results also showed that the shape of holes is the most influential on buckling behavior of the perforated beam for this case of loading.

Effect of Implanted Delamination and Core Density on the Buckling Behavior of Sandwich Composites

2000 ◽  
Author(s):  
Hassan Mahfuz ◽  
Syful Islam ◽  
Leif Carlsson ◽  
Makeba Atkins ◽  
Shaik Jeelani
Keyword(s):  
Finite Element ◽  
Local Buckling ◽  
Sandwich Composites ◽  
Core Density ◽  
Sandwich Construction ◽  
Buckling Behavior ◽  
The Face ◽  
Global Buckling ◽  
Plane Compression ◽  
Overall Buckling

Abstract Foam core sandwich composites have been fabricated using innovative co-injection resin infusion technique and tested under in-plane compression. The sandwich construction consisted of Klegcell foam as core materials and S2-Glass/Vinyl ester composites as face sheets. Tests were conducted with various foam densities and also with implanted delamination between the core and the face sheet. The intent was to investigate the effect of core density, and the effect of core-skin debonds on the overall buckling behavior of the sandwich. Analytical and finite element calculations were also performed to augment the experimental observations. It has been observed that core density has direct influence on the global buckling of the sandwich panel, while embedded delamination seem to have minimal effect on both global as well as local buckling. Detailed description of the experimental work, finite element modeling and analytical calculations are presented in this paper.

Buckling Behavior of General Dome Ends under External Pressure, Using Finite Element Analysis

2011 ◽  
Vol 471-472 ◽  
pp. 833-838 ◽  
Author(s):  
Behzad Abdi ◽  
Hamid Mozafari ◽  
Ayob Amran
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Major Axis ◽  
External Pressure ◽  
Geometrical Parameters ◽  
Element Analysis ◽  
Buckling Behavior ◽  
Ellipse Method ◽  
The Finite Element Analysis ◽  
Critical Buckling Pressure

In this paper, the finite element analysis is used to investigate the effect of shape of dome ends on the buckling of pressure vessel heads under external pressure. The Finite Element Analysis (FEA) with the use of elastic buckling analysis was applied to predict the critical buckling pressure. The influence of geometrical parameters such as thickness, knuckle radius, and the ratio of minor axis to the major axis of dome ends, on the weight and the critical buckling pressure of hemispherical, ellipsoidal, and torispherical dome ends, was studied. The four-centered ellipse method was used to describe the geometry of the dome end.

A Shell Element for Buckling Analysis of Thin-Walled Composite-Laminated Members

2018 ◽  
Vol 18 (02) ◽  
pp. 1850021 ◽  
Author(s):  
R. Emre Erkmen ◽  
Bram Gottgens
Keyword(s):  
Polymer Composite ◽  
Composite Laminates ◽  
Shell Element ◽  
Buckling Analysis ◽  
Fiber Reinforced Polymer ◽  
Element Formulation ◽  
Reinforced Polymer ◽  
Buckling Behavior ◽  
Global Buckling ◽  
Thin Walled

This paper introduces a new shell element formulation and investigates the buckling behavior of thin-walled beams composed of fiber-reinforced polymer composite-laminates, which is a primary design concern for thin-walled beams composed of fiber-reinforced polymer composite-laminates due to their slenderness. Although global buckling behavior can be captured using beam-column type two-node simple finite element formulations, shell-type more sophisticated elements are needed in order to be able to capture the effects due to cross-sectional deformations. Pursuit of an efficient shell element formulation continues to date and in this study, a new flat rectangular shell element formulation is developed for the buckling analysis of thin-walled composite-laminated members. The plate component of the shell is locking-free and based on the twist-Kirchhoff theory. For the membrane component of the shell element, variational formulation employing drilling degrees of freedom is adopted. Convergence studies were presented to illustrate the numerical performances of the element. A broad class of problems including distortional as well as global buckling cases were solved and compared with solutions from the literature to validate the use of the developed shell element for the buckling analysis of thin-walled composite-laminated members.

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