The buckling and post-buckling behaviors are analyzed for the multilayer functionally graded graphene platelets reinforced piezoelectric (FG-GRP) plates. The FG-GRP plates are subjected to the ...external electric potential and axial forces, including the uniaxial loading and biaxial loading. The graphene platelets (GPLs) disperse uniformly and parallelly in each graphene platelets reinforced piezoelectric composite (GRPC) layer, but they spread grading across the thickness of the FG-GRP plates. The effective Young’s modulus of each layer for the FG-GRP plates is calculated by the Halpin-Tsai parallel model. The rule of the mixture is employed to predict the Poisson’s ratio, effective mass density and piezoelectric properties of each layer of the FG-GRP plates. The governing equations of motion for the FG-GRP plates are obtained by the first-order shear deformation plate theory, von Karman nonlinear theory and principle of virtual displacements. To obtain the buckling and post-buckling behaviors of the FG-GRP plates with different boundary conditions, the differential quadrature (DQ) method and a direct iterative technique are combined to solve the governing equations of motion for the FG-GRP plates. The impacts of the external electric voltage, distribution pattern, volume fraction, piezoelectric properties, length-to-thickness of the GPLs and geometry of the plates on the critical buckling load and post-buckling equilibrium paths of the FG-GRP plates are discussed in detailed. It is clearly illustrated that the GPLs have a significantly enhancing influence on the buckling and post-buckling strength of the FG-GRP plates.
Scissoring in thick bars suppresses buckling behavior in serpentine traces that have thicknesses greater than their widths, as detailed in a systematic set of analytical and experimental studies. ...Scissoring in thick copper traces enables elastic stretchability as large as ≈350%, corresponding to a sixfold improvement over previously reported values for thin geometries (≈60%).
Local buckling of structural steel shapes Seif, Mina; Schafer, Benjamin W.
Journal of constructional steel research,
10/2010, Letnik:
66, Številka:
10
Journal Article
Recenzirano
The objectives of this paper are to (1) provide analytical expressions for the elastic cross-section local buckling stresses, including element interaction, of hot-rolled steel structural shapes, and ...(2) compare these local buckling results to the assumptions inherent in the local slenderness limits of the US AISC structural steel specification. The cross-section local buckling stress is determined by finite strip analysis (FSA). Local stability of each cross-section in the AISC shapes database (excluding pipes) is considered in axial compression, as well as positive and negative bending about the major and minor geometric axes. Local buckling stresses are converted into plate buckling coefficients (
k
’s) and simplified expressions are provided for all observed
k
’s. The new
k
’s explicitly include elastic web-flange interaction amongst the elements comprising the cross-section. The
k
values from the FSA are compared to those inherently assumed in the AISC Specification, significant differences are observed.
Buckling of thermalized elastic sheets Morshedifard, Ali; Ruiz-García, Miguel; Abdolhosseini Qomi, Mohammad Javad ...
Journal of the mechanics and physics of solids,
April 2021, 2021-04-00, 20210401, Letnik:
149
Journal Article
Recenzirano
Odprti dostop
Steady progress in the miniaturization of structures and devices has reached a scale where thermal fluctuations become relevant and it is thus important to understand how such fluctuations affect ...their mechanical stability. Here, we investigate the buckling of thermalized square sheets under either compression or shear. We demonstrate that thermal fluctuations increase the critical buckling load compared to the classical Euler buckling load due to the enhanced scale-dependent bending rigidity for sheets that are much larger than a characteristic thermal length scale. The presented results are universal and apply to a wide range of microscopic sheets. These results are especially relevant for atomically thin 2D materials, where thermal fluctuations can significantly increase the critical buckling load because the thermal length scale is on the order of nanometers at room temperature.
•Local shear buckling of beams with trapezoidal corrugated webs analysed using FEA.•Elastic buckling analyses on 90 cantilever beams were performed.•Influence of web thickness, panel width and web ...height was investigated.•Shear buckling coefficient was compared against existing theoretical equations.•Equation to approximate the local shear buckling coefficient is recommended.
A corrugated web beam (CWB) is a variation to the universal hot rolled or welded I section. CWBs usually comprise of wide thick plate flanges and a thin corrugated web. Due to the accordion effect shear is carried primarily by the corrugated web while bending moments are resisted by the flanges. Under shear action three different modes of shear buckling may be realised in the web – local, global or interactive.
This paper describes analyses performed to investigate the local shear buckling behaviour of beams with trapezoidal corrugated webs. Finite element models of cantilever beams with different web geometries were prepared and an elastic eigenvalue buckling analysis was performed using the program ABAQUS. The influence of web thickness, panel width and web height on the local shear buckling coefficient kL was investigated. Values of kL were compared against existing equations from theory and other research. The effect of these dimensions on the local shear buckling stress was also considered. In total, 90 models were analysed.
Overall, it was found that the value of kL lies between 5.34 and 8.98. This corresponds to panel boundary conditions that are between simply supported and clamped. The analysis results revealed that kL increases with stockier panels (large panel width to height ratio) but decreases with thicker webs. When the panel width was decreased, local shear buckling occurred at larger stress values. Similar results were observed when the web height was decreased and the panel thickness was increased. These results are consistent with plate buckling theory. Finally, based on these findings an equation to approximate the local shear buckling coefficient in corrugated web beams is recommended.
•Unprecedented effects of unconstrained length of railway tracks are highlighted.•Physical nature of track buckling is studied using nonlinear FEM models.•Interspersed approach can shift failure from ...progressive to snap-through buckling.•Buckling of timber sleepered tracks can be prevented by interspersed approach.•Track lateral resistance plays a significant role in track buckling prevention.
In a conventional railway system, timber sleepers have been widely used for ballasted railway tracks to carry passengers and transport goods. However, due to the limited availability of reliable and high-quality timbers, and restrictions on deforestation, the “interspersed” approach is adopted to replace ageing timbers with concrete sleepers. The replacement of ageing timber sleepers is frequently done over old and soft existing formations, which have been in service for so long, by installing new stiff concrete sleepers in their place. This method provides a cost-effective and quick solution for the second and third track classes to maintain track quality. Presently, railway track buckling, caused by extreme temperature, is a serious issue that causes a huge loss of assets in railway systems. The increase in rail temperature can induce a compression force in the continuous welded rail (CWR) and this may cause track buckling when the compression force reaches the buckling strength. According to the buckling evidences seen around the world, buckling usually occurs in ballasted track with timber sleepers and thus there is a clear need to improve the buckling resistance of railway tracks. However, the buckling of interspersed tracks has not been fully studied. This unprecedented study highlights 3D finite element modelling of interspersed railway tracks subjected to temperature change. The effect of the boundary conditions on the buckling shape is investigated. The results show that the interspersed approach may reduce the likelihood of track buckling. The results can be used to predict the buckling temperature and to inspect the conditions of interspersed railway tracks. The new findings highlight the buckling phenomena of interspersed railway tracks, which are usually adopted during railway transformations from timber to concrete sleepered tracks in real-life practices globally. The insight into interspersed railway tracks derived from this study will underpin the life cycle design, maintenance, and construction strategies related to the use of concrete sleepers as spot replacement sleepers in ageing railway track systems.
•An accurate nonlinear buckling model is proposed for the flexoelectric cylindrical nanoshell.•The pre-buckling nonlinear deformation is employed to improve the accuracy of critical buckling stresses ...and buckling mode shapes.•The effects of key influencing parameters on buckling characteristics of the flexoelectric cylindrical nanoshell is investigated and reveal.
In this paper, a buckling analysis for flexoelectric cylindrical nanoshells under axial compression is performed by considering the higher-order shear deformation theory and non-uniform pre-buckling deformation. Size-dependent critical buckling stresses and buckling mode shapes are obtained by the Galerkin's method with newly proposed displacement functions. Numerical results are compared with existing solutions and excellent agreements are observed. Furthermore, a comprehensive parametric study of boundary conditions, geometrical parameters and applied electric voltage is carried out to reveal the influence of flexoelectric effect on the size-dependent buckling characteristics of flexoelectric cylindrical nanoshells.
This paper deals with the elastic shear buckling behavior of trapezoidally corrugated wall plates in vertically or horizontally Corrugated Steel Plate Shear Walls (CoSPSWs) considering constraints ...from neighboring subpanels and boundary frame members through eigenvalue buckling analyses and static analyses. Results showed that constraints from boundary frame members along the corrugated edges of wall plates had obvious influences on the shear buckling behavior, while constraints along the straight edges had negligible influence. When the waveform configuration remained the same, the global shear buckling stress of corrugated wall plates increased slightly with the plate thickness, reduced obviously with the straight edge length but barely changed with the corrugated edge length. When the external dimension and thickness remained the same, the global shear buckling stress of corrugated wall plates increased most significantly with the inclined subpanel width, corrugation angle, or corrugation depth. Formulas were proposed for the local shear buckling coefficient, global shear buckling coefficient and interactive shear buckling correlation coefficient of vertically and horizontally corrugated wall plates in CoSPSWs considering constraints from neighboring subpanels and the boundary members. A mode factor was defined to predict the dominant shear buckling mode, and a comprehensive formula was proposed to calculate the shear buckling stress of corrugated wall plates, with good accuracy within the given ranges of geometric parameters from practical engineering.
•Constraints from neighboring subpanels have obvious influence on local shear buckling behavior.•Boundary member constraints on corrugated edges have great influence on global shear buckling behavior.•Formula of local shear buckling stress of corrugated wall plate is revised and proposed.•Formula of global shear buckling stress of corrugated wall plate is revised and proposed.•Correlation formula for interactive shear buckling stress of corrugated wall plates is given.
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