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The present paper successfully develops a closed form solution based on a shear deformation theory for elastic lateral-torsional buckling analyses of simply supported thin-walled steel beams. The theory captures the shear effects caused by transverse bending, lateral bending and warping deformations. The closed form solution is successfully validated against 3 dimensional finite element analyses conducted in commercial software. Through various comparisons between the buckling resistances based on a non-shear deformation theory and the buckling resistances based on the present shear deformation theory, the present study finds that (i) the effect of shear deformations on the buckling resistances decreases when the beam span increases, (ii) the effect of shear deformations on the buckling resistance is sensitive with the change of the flange width, and (iii) the effect of shear deformations in general is also influenced by the change of the section depth, and the flange and web thicknesses.

In the present study, a novel quadrilateral element, namely SQ4C, combined with the Timoshenko beam element is proposed for the static and buckling analyses of stiffened plate/shell structures. The idea behind these elements is a treatment for shear locking as well as membrane locking arising from the framework of the first-order shear deformation theory and a mesh with curved shell geometry. Formulations with eccentricity are also presented in this paper for the general case. The static and buckling analysis solutions and comparison with other available numerical solutions are presented to illustrate the robustness of the proposed elements to stiffened plate/shell structures. This paper also helps engineers in supplementing their knowledge.

New pipelines made with composite materials have to be well-designed for better mechanical performances. Recommendations for sizing stratified pipes have been proposedfor different combinations of loads. In this context, our paper focus on buckling on laminated composite pipes, using numerical simulation. As a first part, we study free-defect pipes buckling for different pipe diameters, wall thicknesses and fibers orientation. In a second part, we evaluate the influence of defects (notches and crack due to notches), their parameters (size, orientation) and mechanical constraints (pipe under pressure, boundary conditions) on the structure. Results show a strong dependence of the size of the notch to the stability of the structure, amplified by the fibers orientation. Thus, for fibers oriented at an angle close to 20°, pipes manufacturing under these conditions show a particular strength of the structure. The crack length (independently on its orientation) seems to have no significant effect on the buckling factor and therefore the structure integrity, for transverse-orientated fibers and while their orientation go beyond 40°. The main variations are observed when fibers orientation is in the range from a few degrees up to 40°. Results are and discussed according the orientation of crack and fibers.

The porosity gradient functionally graded material (PFGM) is one of the most popular types of FGM, in which the porosity in the material is made to change in the specified direction. This study looks into the buckling problems of rectangular sandwich plates made of single-phase porous functionally graded materials (PFGMs), commonly used in aircraft structures and biomedical applications. A compression test was performed on the 3D-printed polymeric FG specimens bonded with two thin solid face sheets on the upper and lower surfaces. The critical stress of well-designed and fabricated 3D printed FGM plate samples with various metal core types is determined using a PC installed on universal testing equipment (UTM). The effect of different essential parameters (such as porous ratio, gradient exponent, and aspect ratio) on buckling load and total deformation were explored.The finite element method (FEM) was used to run a numerical simulation on elastic buckling using ANSYS 2021 R1 software to validate the experimental results. The load-displacement relationships and deformed morphologies were investigated using experiments and numerical analysis. The topology arrangement and relative density of the polymer core were examined using the SEM micro-tomography test based on porosity distribution to check the resistance of the sandwich to buckling load. PETG/Al sandwich plates have been found to have critical buckling loads that are 2.52 % higher than PLA/Al sandwich plates, while TPU/Al sandwich plates show increased essential loads of buckling of 5.139 %. The FEM and experiment results show that the existence of porosity in the PLA core in the PFGM plate can reduce the buckling strength tremendously, about 10.52% and 6.8 %, respectively. It was evident that the numerical results show a good agreement with the experimental findings, with a maximum discrepancy of no more than 12 % occurring at the (TPU/Al) sandwich plate with a porosity of 30%.

Buckling analysis of a vertical structures is crucial in structural design for various loads, and simultaneously, reducing the long structures mass is essential for minimizing weight and cost. This study involves the analysis of long structures with rectangular and circular cross-sections under compressive loads, calculating the buckling load multiplier. Additionally, hollow rectangular and hollow circular columns are designed and analyzed under the same load and boundary conditions as the solid counterparts. By varying the hollowness of the rectangular and circular columns, the buckling load and the percentage of mass saved compared to solid columns are determined. At the same volume of material, the rectangular structure exhibits a 3% higher load multiplier than the circular structure. Increasing mass reduction by introducing hollowness also decreases the buckling load multiplier.

Performance-based Seismic Engineering is the modem approach to Earthquake Resistant Design to control lateral deflection and inter-story drifts. It is a significant challenge to overcome in the execution of high-rise buildings. Since structures are subjected to lateral loads, the Utilization of dissipation devices such as the bracing, shear wall, and dampers are a possible method to enhance the structural performance of the high-rise building under load cases. These cases are varying to static and dynamic ones as Response Spectrum. Properly designed and detailed structures with dissipation devices have exhibited excellent performance during a severe earthquake. Lateral forces due to will be resisted in its plane. In continuation studies of reinforced concrete structure compared to the absorbing devices, Three essential reinforced concrete buildings were taken for analysis G+ 30 floors to cover the broader spectrum of high-rise building construction. Software ETABS carried out seismic analysis through Response Spectrum Analysis. The result highlights how structural damper systems perform much better than other systems with accuracy and exactness through the parameters of Displacement, Drift, Base shear, and Stiffness. Damper structures are more suitable for high-rise buildings and earthquake zones due to this study's results; maximum height of systems could be possible, which must be economically less expensive than steel structure of the same height.

The use of composite materials is growing up compared to the traditional materials, in basically all the industrial domains, where we need powerful, lightweight and cost effective structures. An example of a challenging lightweight structure made of composite materials are wind turbine blades. Indeed, the modern wind turbine blades are becoming dramatically bigger, and nowadays a length of a standard one is over 60 m. The wind turbine blades are often facing extremely complex loads due to environmental conditions they are working in. One of the main loading acting on the wind turbine bale are pressure load, which can engender flap wise and edgewise bending. On the other hand, the consequence of optimum design strategy, the wind turbine blades are becoming thin-walled structures, which raise the risk of buckling phenomena. Therefore, the understanding of the wind turbine blade behaviour under this kind of aforementioned load is very crucial. In this study, the buckling behaviour of the spar cap of a wind turbine blade using the finite element method is investigated. For so doing, a generic NACA 634- 421 airfoil section is considered. The spar cap is taken as a multilayer curved cylindrical shell. A parametric study is made in order to study the effect of material choice, stacking sequence and number of layers on the buckling resistance of the spar cap. The results showed that the buckling load is very sensitive to the considered parameters.

This paper presents a novel hybrid FEM-based approach to establish the mathematical model for solving the nonlinear buckling problem of truss systems with length imperfection under mechanical and thermal load. due to constant temperature change-based hybrid FEM. The proposed approach deals with establishing hybrid types of truss elements, including perfect truss elements without thermal deformation and truss elements with length imperfection and thermal deformation. The equilibrium equation of both truss elements is established based on compatibility relationships considering geometric nonlinearity. The hybrid global equilibrium equations of truss systems are developed by assembling constructed perfect truss elements without thermal deformation and truss elements with length imperfection and thermal deformation. The incremental-iterative algorithm based on the arc-length method is used to establish calculation programs to solve the hybrid global equilibrium equation for investigating the geometrically nonlinear buckling behavior of the truss system. The numerical test is presented to investigate the buckling and post-buckling behavior of truss systems having some elements with length imperfection under thermal and mechanical load.

Cold-rolled aluminium sections are the new products introduced by BlueScope Permalite. These products have illustrated their cost-effectiveness in comparison with the traditional extruded aluminium alloy sections, which has attracted the attention of users and researchers. Research projects on cold-rolled aluminium alloy structures have been carried out to investigate the strengths and behaviors of such members that are the base for the development of the design guidelines for this new structural type. Cold-rolled aluminum alloy sections in the form of thin-walled sections are sensitive to instability. The design guidelines, therefore, have been proposed on the basis of the design of cold-formed steel structures with the development of the Direct Strength Method. The buckling analyses are conducted to determine the elastic buckling load, which is a compulsory step for the application of this method. The buckling analyses for symmetrical sections have been thoroughly investigated whereas these analyses for asymmetric sections are not clearly regulated in the design standards. Based on the experimental and numerical investigations on cold-rolled aluminium asymmetric section beams in a research project conducted at the University of Sydney, the paper will investigate the elastic global buckling moments of these asymmetric beams by using different methods including numerical, experimental and theoretical methods. The investigated results are subsequently discussed to figure out the procedure for the determination of elastic global buckling moments of the investigated cold-rolled aluminium alloy asymmetric section beams.

The term of shear lag is related to the discrepancies between the approximate theory of the bending of beams and their real behaviour, and it refers to the increases of the bending stresses near the flange-to-web junctions, and the corresponding decreases in the flange stresses away from these junctions.

Reinforced concrete (RC) frames are commonly built together with shear walls. In high seismicity regions, constructing shear walls along the frame’s height is proven ineffective. Thus, in numerous studies, using shear walls at a certain height is beneficial, and this kind of structure is popularly known as curtailed shear walls. However, the area above the curtailed walls could suffer significant deformation under high seismic load and upgrading the seismic performance in those upper parts is needed. In this study, the seismic performance of 2-dimension RC frame building with curtailed walls is improved by installing buckling-restrained braces (BRBs). The seismic response is performed through non-linear dynamic analysis using an open-licensed software, STERA_3D. To determine the ideal number and location of the BRBs above the curtailed walls, a classical genetic algorithm is exercised using Python language programming. The parameters involved in optimizations are inter-story drifts, the number of BRBs, and damage indices surround the frames. The result shows that the configuration of BRBs resulted from the optimization could reduce the excessive amount of displacement along the building height. Moreover, the genetic algorithm could give the fittest number and location of BRBs installation to upgrade the seismic response of RC frames with partial shear walls.

The problem of loss of stability of underground pipelines with a middle part in the form of a straight or П-shaped part located in liquefied soils is considered in the article. The pipeline lifting process occurs under the action of buoyancy force in the liquefied soil zone and then under the action of the longitudinal compressive force that appears due to the temperature of the transported product and its pressure. The problem is solved by the finite element method. The results are presented as a table and graphs of changes in the values of transverse displacements along the coordinate depending on the pipeline geometric characteristics and the soil rheological properties. It is established that the П-shaped part is a damper against pipeline buckling.

In this paper, a refined trigonometric shear deformation plate theory is applied for the buckling analysis of thick isotropic square and rectangular plates. The theory involves only two unknowns, as against three in first order shear deformation theory and other higher order theories. The theory involves sinusoidal function in the in-plane displacement. The transverse displacement involves bending and shear components. Governing equations and boundary conditions of the theory are obtained using the principle of virtual work. A simply supported isotropic rectangular plate subjected to uniaxial and biaxial compression is considered for the detailed numerical study. Results of critical buckling load for simply supported isotropic rectangular plates are compared with those of other refined theories.

This paper is concerned with the approach to implementing the Penalty function method for imposing multi-freedom constraints in geometrically nonlinear analysis of imperfect trusses based on mixed finite element formulation. Using a finite element model based on displacement formulation, it is required to incorporate both the dependent boundary relations and initial length imperfection to the nonlinear master stiffness system of equations for solving the geometrically nonlinear problem of imperfect truss with multi-freedom constraints. For decreasing the mathematical complexion of the incorporating process, the author proposes a novel mixed finite truss element considering initial imperfection, used in building the model for solving the geometrically nonlinear problem of truss with multi-freedom constraints. The modified nonlinear stiffness equation is constructed by employing the penalty function method to convert a constrained problem into an unconstrained problem by extremizing the augmented energy function established based on the proposed mixed finite element formulation. For solving the nonlinear equilibrium equation of imperfect trusses with multi-freedom constraints, the incremental equilibrium equation is constructed, and the incremental-iterative algorithm for calculation is established utilizing the arc-length method, used for writing the calculation program for investigating geometrically nonlinear behavior of imperfect truss with multi-freedom constraints. The results of the numerical test show the influence of initial imperfection and choosing weight values on the equilibrium path of the truss.

The research object of this work is a clamped rectangular plate made of glass-reinforced plastic. The dynamic problem of stability of the plate under rapidly increasing shear load is considered. Within the Kirchhoff–Love hypothesis framework, a mathematical model was built in a geometrically nonlinear formulation. By the Bubnov–Galerkin method, based on a polynomial approximation of the deflection, the problem was reduced to solving systems of nonlinear ordinary integro-differential equations. With a weakly singular Koltunov–Rzhanitsyn kernel with variable coefficients, the resulting system was solved by a numerical method based on quadrature formulas. The plate’s dynamic behavior was investigated depending on the plate’s geometric and physic parameters. The importance of considering the viscoelastic properties of the material is shown.

Buckling-Restraint Braces (BRB) is a new type of bracing system with energy dissipation mechanisms developed to improve the behaviour of conventional braces. In this system, the bracing member is placed in a metal or concrete casting that prevents this member from experiencing failure due to the lateral buckling. By implementing these changes, the brace's behaviour in compression is identical to its behaviour in tension, which is accompanied by yielding of material and therefore buckling does not occur. In this paper, the effect of the BRB system on the seismic performance of a typical frame is evaluated using the finite element method. Numerical studies using ABAQUS software are conducted to develop a 3D model of a BRB system, considering the nonlinearity effects of material and geometrical deformation. The BRB component is analysed under the cyclic loading protocol recommended by FEMA 450 and the resultant hysteretic behaviour of BRB is compared with the experimental work. The results show that the application of this system in structures may improve the stability of the structural system and enhance the energy dissipation mechanisms in the buildings. As a result, the structural design will be safer and more economical.

The paper is devoted to the problems related to buckling analysis of graphene sheets without and with vacancies in the structure under different boundary conditions. The analysis was performed by the classical numerical treatment – the finite element method (FEM). The graphene sheets were modelled by beam elements. Interatomic relations between carbon atoms in the structure were represented by the beams connecting individual atoms. The behaviour of the beam as structural element was based on the properties that were established from relations of molecular mechanics. The vacancies in single layer graphene sheets (SLGSs) were created by elimination of randomly chosen atoms and corresponding beam elements connected to the atoms in question. The computations were accomplished for different percentage of atom vacancies and the results represent an obvious fact that the critical buckling force decreases for increased percentage of vacancies in the structure. The numerical results are represented in form of graphs.

In this work, the dynamic buckling of stiffened panels is evolved numerically through a nonlinear incremental expression through making use of a specific time integration procedure via the finite element software program. the buckling and post-buckling behaviours of hat-stringer-stiffened composite curved panel under axial compression load .Dynamic buckling is extracted from the curve abandoning the very last shortening as a characteristic of time while the shape is subjected with the aid of a square compression pulse movement carried out inside the axial direction. The duration of the heart beat and the amplitude of curvature of decreasing of the cloth inside the band tormented by the warmth, the dynamic buckling motion, are constant. The method approach was proposed to predict the dynamic buckling load of curved panel. Finite element analysis was used to investigate these tests and the FE models were performed by ABAQUS.Approach to determine the reliability of the stiffened panel in dynamic buckling state.

The stability analysis for compressed bars with variable rigidity is studied, by using the finite element method (FEM) in Galerkin’s variant. The general shape of elastic and geometrical stiffness matrices are obtained for stepped and tapered bars. In a study case, the critical buckling load obtained by using FEM, for three columns with constant and variable sectional stiffness (in steps and continuous variation), is evaluated in comparison with others analytical and numerical methods.

The stretchable composite thin-walled lenticular boom can be used in the unfolding process of a large spacecraft structure, and its buckling characteristic is one of the focuses of structural design. In this paper, firstly, the critical buckling load formula is derived based on Euler’s formula and laminated theory for the axial compression buckling problem of the lenticular boom, and verified by the finite element method. Secondly, the influence law of the lenticular boom section and layer parameters on the critical buckling load is quantitatively analyzed. The results show that the lenticular boom generally undergoes first-order buckling in the outer direction of the symmetrical bonding surface. The critical buckling load is most significantly affected by the radius of the convex arc, followed by the center ordinate of the convex arc, the thickness of the layer, and the angle of the layer. And these parameters are positively related to the critical buckling load. The radius of the concave arc and the length of the straight section have little effect on the critical buckling load. The research methods and conclusions of this paper can provide reference for the engineering design of the lenticular boom structure.

This paper presents a novel hybrid FEM-based approach for nonlinear buckling analysis of truss with initial length imperfection. The contribution deals with establishing two types of truss finite element (perfection and imperfection element) considering large displacement based on displacement formulation and mixed formulation. Therefore, the hybrid global equation system is developed by assembling perfection and imperfection truss elements. The incremental-iterative algorithm based on the arc-length method is used to establish calculation programs for solving geometrically nonlinear buckling analysis of truss with initial length imperfection. Using a written calculation program, the numerical test is presented to investigate the equilibrium path for plan truss with initial member length imperfection.

This paper presents an analytical and numerical study of the lateral buckling of beams with double symmetrical I and H cross sections having substantially the same plastic modulus of resistance around the strong axis subjected by a uniformly distributed load in order to understand the influence of the one of the forms during lateral buckling. For this, a critical elastic moment analysis is carried out using ANSYS software using the element SHELL181 and analytical formulas from Eurocode3. Finally, there is a presentation of the non-linear behavior of these two cross sections.

The objective of this article is the investigation of the elastic buckling strength of cylindrical simply supported GLARE (GLAss REinforced) panels subjected to axial compression using probabilistic analysis methods, so that the effect of uncertainties associated with material properties and dimensions of the panels on their elastic buckling load can be evaluated. The mechanical properties of aluminum along with the dimensions of aluminum and unidirectional (UD) glass-epoxy layers are considered to be random input variables whereas the critical buckling load is defined as a random output parameter. The employed eigenvalue buckling analysis and the probabilistic finite element analysis were carried out with ANSYS software. The Probabilistic Design System (PDS), along with the Monte Carlo Simulation and the Latin Hypercube Sampling method were used for the calculations. It is found that the thickness of aluminum layers has the strongest effect on the buckling strength, among the considered random input variables. It is also demonstrated that there is a considerable probability for the buckling load of GLARE panels to be overestimated when a deterministic analysis is conducted.

In this article, the elastic buckling behaviour of cylindrical GLARE (GLAss REinforced) panels with classically simply supported boundary conditions under uniaxial compression is investigated using the finite element method (FEM) and eigenvalue buckling analysis. The buckling coefficient-curvature parameter diagrams of five GLARE grades are obtained and studied along with the diagrams of two glass-fiber composites and monolithic 2024-T3 aluminum, using validated FEM models. It is found that aluminium has a stronger impact on the buckling behaviour of the GLARE panels than the composite layers. From the constructed buckling coefficient - curvature parameter diagrams in double logarithmic scale it is found that there is an approximately linear relation between the buckling coefficient and the curvature parameter of the panels. Based on this finding, appropriate regressions are implemented in order to derive approximate analytical formulas of the buckling coefficient as a function of the curvature parameter for the considered materials.

In this study, non unified local shear deformation theory is proposed to consider the bending and buckling of nano beams. This theory is based on the assumption that the cross-sectional and planar displacements consist of bending and shear components, shear components do not contribute to the bending moments. Motion equations are derived using the Hamilton’s principle. Analytical solutions for deformation, buckling load, and the natural frequency are presented to a nano simply supported beam, and the results obtained are compared to those proposed by the nonlocal Timoshenko beam theory and Reddy beam theories

The post buckling of a rectangular slender web in compression has been analyzed. Shapes of a buckling area obtained from the nonlinear analysis have been compared with buckling modes from the linearized problem for various aspect ratios. Effects of initial shape imperfections upon the analysis have been investigated using nonlinear approach. To trace the complete nonlinear equilibrium curves, specialized code based on FEM was created. The Newton-Raphson iteration algorithm was used, load versus displacement control was changed during the process of calculation. Obtained results were verified using Ansys system, in this case arc-length method was activated for overcoming critical points.

The transverse shear behavior of the composite beams can be critical and must therefore be properly represented by the various models of structures normally used to predict their behavior or to identify their properties. We propose in this work, a warpage analysis in short laminated beams using a simple analytical approach based on the theories of higher order.

We propose an improved version of the energy method in calculating rectangular beams for the stability of a flat bending shape. The essence of this variant of the method is to use the principle of the minimum total energy instead of the condition for the equality of the potential strain energy and the work of external forces. This version of the method makes it easy to obtain a numerical-analytical solution for any number of members of series. The solution of the problem for a pivotally supported beam is presented taking into account the vertical displacement of the load relative to the center of gravity.

In this paper, the buckling of a functionally graded plate is studied by using first order shear deformation theory (FSDT). The material properties of the plate are assumed to be graded continuously in the direction of thickness. The variation of the material properties follows a simple power-law distribution in terms of the volume fractions of constituents. The von Karman strains are used to construct the equilibrium equations of the plates subjected to two types of thermal loading, linear temperature rise and gradient through the thickness are considered. The governing equations are reduced to linear differential equation with boundary conditions yielding a simple solution procedure. In addition, the effects of temperature field, volume fraction distributions, and system geometric parameters are investigated. The results are compared with the results of the no shear deformation theory (classic plate theory, CPT).

Cellular steel beam is flanged steel beam with circular openings of uniform diameter and distance between each opening. The main benefit of such beam is to reduce the structural weight without reducing the strength significantly. A rectangular steel plate with circular opening is frequently used as a model of a web panel of such beam with vertical web stiffeners. The dimension of the plate is the dimension of the web bounded by top and bottom flanges and two adjacent vertical stiffeners. In this research, finite element method is utilized to perform inelastic buckling analyses of rectangular steel plates with circular openings under shear forces along all four edges assuming steel as elastic-perfectly-plastic material with yield stress of 250 MPa. Both nonlinear geometry and nonlinear material are considered in the analyses. The objective of this research is to study buckling behavior of the plate in terms of buckling mode, critical load, and Von Mises (effective) stress distribution. The buckling shear loads of the plates of various length-to-width ratios of the plate (1.0, 1.25, and 1.50) and various opening-diameter-to-plate-width ratios (0.00, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, 0.40, 0.45, 0.50) have been obtained from the analyses. The deformation and Von Mises stress distribution at every load level have been obtained as well from the finite element analyses. Equation to predict inelastic buckling shear force of a rectangular steel plates with circular opening under shear forces is proposed in this study. Verification of the method has been performed by comparing shear buckling loads resulted from finite element analyses with the analytical results in the elastic range.

The paper presents the results of studies of the buckling of the bearing elements of the new structural system, which consists of reinforced concrete precast-monolithic panels-frames produced industrially under a special accidental impact caused by a sudden column removal from the building frame. It is established that under special accidental impact caused by a sudden column removal from RC precast-monolithic structural system consists of industrial panel-frame elements, the reason of the fracture spreading within and outside local damage (fracture) zone may be the buckling of compressed-bent elements.

This paper discusses different aspects of analytical and numerical modelling of the buckling resistance of welded I-section columns subjected to axial compression. The section considered is of class 1 that implies no local buckling affecting the column performance. The proposed analytical formulation of the buckling resistance is based on the so-called Marchant-Rankine's-Murzewski approach (M-R-M approach). The model proposed is of a 2D type and is a simplification of the 3D one that has recently been presented by the authors. The parameters of equivalent stress-strain model of the postwelding steel are calibrated in two stages of the best fit approximation procedure and with use of numerical results of the finite element simulation of the buckling resistance. In the first stage, the postyielding inelastic tangent stiffness parameter ξE,eff is evaluated with fixed value of the first yield parameter ψeff= ψcom. A target of the second stage is to assign the best fit value of the first yield parameter ψeff and the imperfection factor n that allows for accounting the effect of geometric imperfections.

The paper deals with the lateral buckling problem of a freely supported wooden strip with a constant narrow cross section, loaded with a local force in the middle of the span. A differential equation is given for cases when the force is applied out of the gravity section center. Strain-energy method was used in the study of beam lateral buckling. In the case when the load is applied in the center of gravity, problem comes down to a generalized characteristic equation. The correlation between the magnitude of the critical force and the application point of the load was obtained. The linear approximating function was identified for the indicated dependence. The obtained results are compared with an analytical solution using the Bessel functions and a numerical iterative method.

Elastic and inelastic lateral torsional buckling of simply web tapered I beam is studied using the finite element method. The length of the beams is 8000 mm for elastic lateral torsional buckling and 4000 mm for inelastic lateral torsional buckling. The depth of cross section at one end is 500 mm and at the other end it is varied. The thickness of the flange is 16 mm and the thickness of the web is 10 mm. The section of the beams is compact. The beams are loaded by end moments. The ratio of end moments at one end and the moments at the other end are varied. The beams are assumed to have geometric imperfection and the distribution of imperfection follows the shape of the first buckling mode of elastic lateral torsional buckling of the beam. The amplitude of the imperfection is taken one milimeter at the top flange in lateral direction. The load is increased until the beams collapse. The ultimate load is considered as the critical moments of the beams. The results of the analysis are compared to nominal lateral torsional buckling moments using the method presented in the AISC Design Guide 25 (Design Guide for web tapered members). It can be concluded that usually the critical moments of the collapse analysis are close to the critical moments of the design guide. But sometimes it is less than the design guide and it means design guide is sometimes is not on the safe side.

Pitting corrosion, an extremely localized corrosion that leads to the creation of small holes in metal when a protective coating is damaged could trigger structural failure in platform structures. A single pit in a critical point, especially in compression element, can cause a great deal of reduction in overall buckling capacity of the structure. This study aims to indicate the effect of a circular cutout, representing a pitting corrosion on overall buckling capacity of steel pipe truss structure subject to static loading. Five models of truss structure having a circular cutout on their compression elements had been tested experimentally up to failure. The truss structures were made of steel pipes and contain only 2 elements as representation of part of real platform. The single cutout were located at 0.5L, 0.25L and 0.125L, where L is the length of the compression element. Two models without cutout had been used as control models. The overall buckling capacity of the truss were compared to similar truss based on the element buckling of compression element. The experimental test results, represented by nonlinear load deflection curves and their associated critical loads as well as buckling modes, had been verified numerically by eigenvalue and geometric nonlinear finite element analyses utilizing 3D solid elements on ABAQUS. The results showed that: (a) in the truss model with various hole positions, the overall buckling loads were slightly higher than that of element buckling loads: (b) the presence of cutout reduced the overall buckling capacity of the structure, (c) the capacity reduction factors depend on the cutout locations and (d) the lowest capacity reduction factor of 0.882 was associated with the presence of cutout at the middle of compression element.

The paper presents a study of behaviour of axially loaded columns that consist of two flanges and a thin triangularly corrugated web, connected by automatic welding. In the literature, the buckling behaviour of steel columns was dealt with mostly for members with plate webs. Researches of that problem for columns with corrugated webs were found out to be very limited. A parametric study is carried out for various column slenderness and corrugation densities. A general-purpose finite element analysis software ABAQUS was used. The corrugation densities adopted in this study represent practical geometries, which are commonly used for such structures in building practice. Plot showing the influence of section slenderness on value of reduction factor for lateral buckling is presented. It is determined that existing buckling curves poorly describe the dependence of the reduction factor on slenderness for axially compressed members with triangularly corrugated webs. Finally, recommendations were proposed for the design of pin-ended columns with corrugated webs at lateral buckling in accordance with numerical results.

Stress redistribution will occur around the hole for the perforated plate under bending, and the buckling mode of bending plate is changed, which makes the design of bending plate more complicated. The finite element software ABAQUS is used to establish the perforated plate under bending model, analyze the degree of influence of the plate aspect ratio, width-thickness ratio, size and position of the holes, meanwhile, the distance between holes is also discussed. The results show that the thickness of the plate size and width-thickness ratio have little influence on the elastic buckling performance of thin plates with holes in bending. As the size of the holes increase, the influence is greater, and there is a certain regularity. The opening position is closer to the short side of the plate, the buckling coefficient of plate will be significantly decreased. The effect is greater with the increase of opening size, the distance between holes have a safe value, the position of the opening is more obvious for the buckling of the bending plate. Finally, based on the data from finite element analysis, the proposed formula of buckling stability coefficient k for the bending perforated plate is given.

Based on the comparison on buckling stability coefficient between local and distortional buckling, the critical cross-sectional dimensions without considering the distortional buckling for cold-formed steel lipped channel members are put forward. Furthermore, the critical effective length of nonoccurrence of distortional buckling is presented. The research results show that the calculation of distortional bucking strength of cold-formed steel lipped channel members can be avoided by controlling the reasonable cross-sectional dimensions or the effective length.

There is a significant increase in the application of laminated glass panel in the modern and innovative construction industry. Glass element is frequently used as a structural component because of its aesthetic and allows abundance of daylight shining in through in which leads to energy saving. The glazing consists of two thin glass plates bonded together by a thin core material called polyvinyl-butyral (PVB). A laminated glass panel is typically brittle and slender, thus frequently subjected to buckling. This paper focuses on the load-carrying behaviour of laminated glass panel supported merely along four edges subjected to compressive force. A 1 m x 1 m laminated glass panel with glass plies of 8 mm thick and the interlayer thickness of 1.52 mm is modeled and analyzed through nonlinear static analysis by using ABAQUS finite element (FE) analysis software. The behaviour of the laminated glass panel under buckling and post-buckling analysis was presented. Analytical approach by Zenkert’s formulation based on the theory of sandwich is utilized to validate the technique used to build the FE model of the glass panel. Essentially, the critical buckling load and the load-displacement relationship are in a good agreement with the analytical formulation and the empirical study respectively. In addition, the significant effect of the interlayer and the slenderness aspect of the panel are also studied. This involves parametric analysis of the configuration of the different interlayer stiffness and the aspect ratio length to width (a/b) of the glass panel. It was found that the rate of decrement of buckling load is indirectly proportionate to the rate of increment of (a/b) ratio. This study also shows that the buckling load of a laminated glass panel depended very much on the slenderness aspect of the structure.

The study reported in this paper employed Artificial Neural Networks (ANN) to predict the critical force of the buckling composite structures. The critical force depends upon various factors such as thickness, stacking sequence, etc. These factors have been identified in earlier studies by means of the Finite Elements Method (FEM). The critical force is affected by the above-mentioned factors. Various approaches have been applied in the course of the presented study. Apart from our FEM simulation, the ANN approach has been applied and the results were compared. The main contribution of these two approaches is the estimation of the critical force. The ANN model is trained to predict the critical force for different configurations of input variables.

This paper presents a numerical finite element model (FEM) investigation on the overall buckling behaviour of hot-rolled (HR), submerged arc welded (SAW) and high-frequency welded (HFW) steel circular columns under axial compression. Three dimensional FEM of circular hollow sections were developed using shell elements considering material nonlinearities, geometric imperfections and residual stress. The established FEM was used to simulate experimental studies conducted by past researchers. Good agreement has been found between numerical analysis and past researchers results, which has validated the reasonability of the FEM to carry out further investigation. Based on the validated FEM, numerical analysis incorporating 180 numerical generated HR, SAW and HFW steel circular columns with various section sizes and slenderness were carried out. The numerical analysis results were compared with the existing column design curves in Chinese, European and American codes. The numerical results showed that the design resistances for hot-rolled and welded steel circular columns calculated based on design curve a in both GB 50017-2003 and Eurocode 3 and the design formula in ANSI/AISC 360-2016 should be accepted. In addition, to further improve the design efficiency, new column design curves for hot-rolled and welded steel circular columns were recommended based on the expressions in GB 50017-2003 and Eurocode 3.

In this work, the size-dependent buckling behavior of functionally graded (FG) nanobeams is investigated on the basis of the nonlocal continuum model. The material properties of FG nanobeams are assumed to vary through the thickness according to the power law. In addition, Poisson’s ratio is assumed constant in the current model. The nanobeams is modelled according to the new first order shear beam theory with small deformation and the equilibrium equations are derived using the Hamilton’s principle. The Naviertype solution is developed for simply-supported boundary conditions, and exact formulas are proposed for the buckling load. The effects of nonlocal parameter, aspect ratio, various material compositions on the stability responses of the FG nanobeams are discussed.

Different aspects of Eurocode 3 General Method (GM) approaches are discussed in this paper. The purpose of present study is to improve the application of GM approach for both beam-columns without intermediate lateral-torsional restraints and with these restraints. The results from the proposed GM are compared with those from Eurocode 3-1-1 interaction equations according to Method 1 and Method 2. A better consistency between the developed GM approach and the Eurocode's interaction equation approach than Eurocode 3 GM approach is observed.

This paper analyzes the influence of geometrical and material imperfections on the buckling resistance of welded I-section columns subjected to axial compression through numerical and analytical models. The paper is divided into two parts. The first part recalls a FEM parametric study of members under compression taking into account different slenderness ratios, as well as different amplitudes of initial crookedness and different values of postwelding residual stresses. The formulation of analytical approach is the main issue of the second part of the paper. Analytical formulation of the buckling resistance is based on a statistical hypothesis of the minima value approach, called the Marchant-Rankine’s-Murzewski approach (M-R-M). Calibration of imperfection factors included in the analytical formulation is made using the results of FEM simulations performed in the first stage of research investigations.

The aim of the article is to present the application of finite element method (FEM) programs ABAQUS/Standard [1] and ABAQUS/Explicit [2] and the constitutive models of incompressible isotropic hyperelastic materials [3] in the analysis of local and global buckling of axially compressed shell elements made of elastomers. Three FEM models of tubes with the same length and initial stiffness have been created for this purpose. These are tubes with elliptical, square and triangular cross-sections. Three types of constitutive models of a rubber-like (elastomeric) material are used - with the polynomial function of elastic energy in the form of the model MV [3] and standard models of Neo-Hooke and Mooney-Rivlin [4]. No imperfections are introduced in the FEM models of the analyzed pipes. Numerical simulations of buckling of pipes are performed for two types of initial-boundary value problems, i.e. quasi-static and dynamic ones. It has been shown that the type of buckling depends on the cross-section of the pipe. The solutions of buckling of pipes modelling with different constitutive models are compared and good correlations of the results have been observed.

Based on the strain assumption and linear mixing rate of Vogit, the physical property parameter expression of functionally graded material plates is obtained. According to the theory of small deformation and Hamilton principle, the dynamic buckling governing equation of functionally graded material plates under longitudinal load is obtained. Using the method of trial function, the analytical expression of critical load and the buckling solution of the functionally graded material plate under conditions of one edge fixed and three edges simply supported is obtained. The analytical expression of critical load is numerically calculated by METLAB. The influence of geometric size, gradient index, modal order and material composition on critical load is discussed. The results show that the critical buckling load decreases exponentially with the increase of critical length, decreases with the increase of gradient index k, increases with the increase of modal order, and the elastic modulus of constituent materials has significant effect on the critical load. The higher-order buckling modes of functionally graded material plates are prone to occur under the condition of high longitudinal load.

The paper is focused on stability analysis of different models of steel cold-formed C-section column. The analysed element may be applied as a primary load-bearing member in steel trusses or silo columns. The column can be used as a support for a wall of roof plates made of corrugated sheets. The wall sheeting that restrains the column against buckling may be considered as an elastic foundation. Due to the design solutions the foundation may be modelled as a series of lateral translational or rotational elastic supports. Such model is used for example in silo column analysis. In the paper linear bifurcation analysis (LBA) of axially compressed columns with different type of elastic foundation is carried by means of ABAQUS software. The analysed thin-walled column (C 250×100×33×4) is regarded as a load-bearing element in a steel hall. The column was modelled by shell elements, the foundation modelled by means of elastic supports. The column length was 5000 mm. The authors present a 3D image of an influence of lateral translational and rotational elastic supports on the buckling resistance of the column.

In this research, buckling behavior of perforated rectangular plate of symmetric and anti-symmetric laminated composite is investigated based on Finite element analysis. The presence of hole may cause redistribution of stresses in plates with reduction of stability. The aim of the current paper is to find critical buckling load by using the (FSDT) first-order shear deformation theory in concomitance with the variational energy method. The load depends on many factors like as diameter of circular hole, different boundary conditions, lay-up sequences, length/thickness ratio and angle of ply orientation. The result is shown in graphical forms for various boundary conditions.

In this paper, we utilize the Finite Element (FE) method to model twisting of long thin rods and capture the bifurcation scenarios leading to heli- cal buckling and various further post-buckling states. Since standard nonlinear beam elements do not account for nonlinearity in torsional mode, we derive a modified beam element, which allows to model complex torsional buckling bifurcation scenarios of a thin rod subjected to twisting load. A series of veri- fication tests (static analysis with load stepping) of the developed code are per- formed to determine critical torsional buckling loads for various helical buck- ling modes and compared with ABAQUS FE simulation.