scholarly journals Using ANN to Estimate the Critical Buckling Load of Y Shaped Cross-Section Steel Columns

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Thuy-Anh Nguyen ◽  
Hai-Bang Ly ◽  
Hai-Van Thi Mai ◽  
Van Quan Tran
Keyword(s):  
Correlation Coefficient ◽  
Cross Section ◽  
Structural Engineering ◽  
Buckling Load ◽  
Model Assessment ◽  
Ann Model ◽  
Critical Buckling Load ◽  
Steel Columns ◽  
Marquardt Algorithm ◽  
Shaped Cross Section

Accurate measurement of the critical buckling stress is crucial in the entire field of structural engineering. In this paper, the critical buckling load of Y-shaped cross-section steel columns was predicted by the Artificial Neural Network (ANN) using the Levenberg-Marquardt algorithm. The results of 57 buckling tests were used to generate the training and testing datasets. Seven input variables were considered, including the column length, column width, steel equal angles thickness, the width and thickness of the welded steel plate, and the total deviations following the Ox and Oy directions. The output was the critical buckling load of the columns. The accuracy assessment criteria used to evaluate the model were the correlation coefficient (R), root mean square error (RMSE), and mean absolute error (MAE). The selection of an appropriate structure of ANN was first addressed, followed by two investigations on the highest accuracy models. The first one consisted of the ANN model that gave the lowest values of MAE = 40.0835 and RMSE = 30.6669, whereas the second one gave the highest value of R = 0.98488. The results revealed that taking MAE and RMSE for model assessment was more accurate and reasonable than taking the R criterion. The RMSE and MAE criteria should be used in priority, compared with the correlation coefficient.

scholarly journals A Numerical Study of the Effect of Component Dimensions on the Critical Buckling Load of a GFRP Composite Strut under Uniaxial Compression

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 931 ◽  
Author(s):  
Quoc Hoan Doan ◽  
Duc-Kien Thai ◽  
Ngoc Long Tran
Keyword(s):  
Uniaxial Compression ◽  
Cross Section ◽  
Numerical Study ◽  
Slenderness Ratio ◽  
Thickness Ratio ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
Channel Section ◽  
Gfrp Composite ◽  
Thin Walled

In the practical design of thin-walled composite columns, component dimensions should be wisely designed to meet the buckling resistance and economic requirements. This paper provides a novel and useful investigation based on a numerical study of the effects of the section dimensions, thickness ratio, and slenderness ratio on the critical buckling load of a thin-walled composite strut under uniaxial compression. The strut was a channel-section-shaped strut and was made of glass fiber-reinforced polymer (GFRP) composite material by stacking symmetrical quasi-isotropic layups using the autoclave technique. For the purpose of this study, a numerical finite element model was developed for the investigation by using ABAQUS software. The linear and post-buckling behavior analysis was performed to verify the results of the numerical model with the obtained buckling load from the experiment. Then, the effects of the cross-section dimensions, thickness ratio, and slenderness ratio on the critical buckling load of the composite strut, which is determined using an eigenvalue buckling analysis, were investigated. The implementation results revealed an insightful interaction between cross-section dimensions and thickness ratio and the buckling load. Based on this result, a cost-effective design was recommended as a useful result of this study. Moreover, a demarcation point between global and local buckling of the composite strut was also determined. Especially, a new design curve for the channel-section GFRP strut, which is governed by the proposed constitutive equations, was introduced to estimate the critical buckling load based on the input component dimension.

Simulation of Compress Buckling Performance of Composite Stiffened Panel

2012 ◽  
Vol 184-185 ◽  
pp. 1189-1193
Author(s):  
Qing Shao ◽  
Yu Ting He ◽  
Teng Zhang ◽  
Hai Wei Zhang ◽  
Qing Shan Kang
Keyword(s):  
Cross Section ◽  
Optimization Design ◽  
Engineering Application ◽  
Buckling Load ◽  
Stiffened Panel ◽  
Critical Buckling Load ◽  
Cross Section Area ◽  
Section Area ◽  
Calculation Results ◽  
Composite Stiffened Panel

Finite element method is applied to analyze the buckling performance of composite stiffened panel. Compress buckling critical loads of six types panels with T or Z-section stiffeners are calculated by FEM. The emulational calculation results show that with same cross section area, critical buckling load of panel with T-section stiffeners increases with the reduction of stiffener pitch and the increase of stiffener numbers, while the buckling load of panel with Z-section stiffeners increases to a certain level and then keep almost changeless. To T-section stiffener panels, the relation between thickness of skin and buckling load is approximately quadratic trinominal. Conclusions obtained can offer a referenced measure for the optimization design and engineering application of the structure.

Shear in Structural Stability: On the Engesser–Haringx Discord

2010 ◽  
Vol 77 (3) ◽  
Author(s):  
Johan Blaauwendraad
Keyword(s):  
Structural Engineering ◽  
Flexural Rigidity ◽  
Thought Experiment ◽  
Quantitative Information ◽  
Buckling Load ◽  
Structural Members ◽  
Buckling Loads ◽  
Critical Buckling Load ◽  
Helical Springs ◽  
Wide Range

Since Haringx introduced his stability hypothesis for the buckling prediction of helical springs over 60 years ago, discussion is on whether or not the older hypothesis of Engesser should be replaced in structural engineering for stability studies of shear-weak members. The accuracy and applicability of both theories for structures has been subject of study in the past by others, but quantitative information about the accuracy for structural members is not provided. This is the main subject of this paper. The second goal is to explain the experimental evidence that the critical buckling load of a sandwich beam-column surpasses the shear buckling load GAs, which is commonly not expected on basis of the Engesser hypothesis. The key difference between the two theories regards the relationship, which is adopted in the deformed state between the shear force in the beam and the compressive load. It is shown for a wide range of the ratio of shear and flexural rigidity to which extent the two theories agree and/or conflict with each other. The Haringx theory predicts critical buckling loads which are exceeding the value GAs, which is not possible in the Engesser approach. That sandwich columns have critical buckling loads larger than GAs does, however, not imply the preference of the Haringx hypothesis. This is illustrated by the introduction of the thought experiment of a compressed cable along the central axis of a beam-column in deriving governing differential equations and finding a solution for three different cases of increasing complexity: (i) a compressed member of either flexural or shear deformation, (ii) a compressed member of both flexural and shear deformations, and (iii) a compressed sandwich column. It appears that the Engesser hypothesis leads to a critical buckling load larger than GAs for layered cross section shapes and predicts the sandwich behavior very satisfactory, whereas the Haringx hypothesis then seriously overestimates the critical buckling load. The fact that the latter hypothesis is perfectly confirmed for helical springs (and elastomeric bearings) has no meaning for shear-weak members in structural engineering. Then, the Haringx hypothesis should be avoided. It is strongly recommended to investigate the stability of the structural members on the basis of the Engesser hypothesis.

scholarly journals SERIES SOLUTION OF LARGE DEFORMATION OF A BEAM WITH ARBITRARY VARIABLE CROSS SECTION UNDER AN AXIAL LOAD

2009 ◽  
Vol 51 (1) ◽  
pp. 10-33 ◽  
Author(s):  
SHIJUN LIAO
Keyword(s):  
Differential Equations ◽  
Cross Section ◽  
Axial Load ◽  
Nonlinear Differential Equations ◽  
Variable Cross Section ◽  
Variable Coefficients ◽  
Buckling Load ◽  
Moment Of Inertia ◽  
Variable Cross ◽  
Critical Buckling Load

AbstractA general analytic approach is proposed for nonlinear eigenvalue problems governed by nonlinear differential equations with variable coefficients. This approach is based on the homotopy analysis method for strongly nonlinear problems. As an example, a beam with arbitrary variable cross section acted on by a compressive axial load is used to show its validity and effectiveness. This approach provides us with great freedom to transfer the original nonlinear buckling equation with variable coefficients into an infinite number of linear differential equations with constant coefficients that are much easier to solve. More importantly, it provides us with a convenient way to guarantee the convergence of solution series. As an example, the beam displacement and the critical buckling load can be obtained for arbitrary variable cross sections. The influence of nonuniformity of moment of inertia is investigated in detail and the optimal distributions of moment of inertia are studied. It is found that the critical buckling load of a beam with the optimal distribution of moment of inertia can be approximately 21–22% larger than that of a uniform beam with the same average moment of inertia. Mathematically, this approach is rather general and thus can be used to solve many other linear/nonlinear differential equations with variable coefficients.

scholarly journals Numerical analysis of steel columns subject to eccentric loadings

2021 ◽  
Vol 4 (1) ◽  
pp. 1-12
Author(s):  
Emmanuel Ufuah
Keyword(s):  
Load Level ◽  
Buckling Load ◽  
Effective Length ◽  
Mode Shapes ◽  
Linear Perturbation ◽  
Eccentric Load ◽  
Allowable Limit ◽  
Critical Buckling Load ◽  
Steel Columns ◽  
Steel Column

Buckling of framed and plated structures has been a great concern that researchers try to handle over the past decades. In most developing nations such as ours, fewer or no experimental trials are available to obtain requisite information for the proper understanding of this phenomenon. It is on this premise that an attempt is made to conduct a preliminary study to numerically evaluate the buckling of steel columns under eccentric loadings. To achieve this, a static, linear perturbation analysis was initially performed on a pin-ended steel column using the subspace Eigen solver for the different buckled mode shapes to illustrate the likely behaviour of the column when subjected to compressive actions. Then, the static, general analysis was conducted with the column subjected to varying magnitudes of eccentric loadings. It was required to determine the load level at which the column would fail when subjected to these eccentric loadings. Consequently, a base load value equivalent to 10 % of Euler's critical buckling load was used. This load value was thereafter increased by 20 % in sequence. It was discovered that 10 % of the Euler's critical buckling load can alter the stiffness of the column when loaded eccentrically. It was further observed that the steel column finally failed at a load greater than 20 % of the Euler's critical buckling load and 40.1% of Rankine's critical buckling load. This is because the permissible deflection for unbraced columns may be taken as the quotient of effective length of column to 250, which translates to 13.8 mm. Therefore, the maximum deflection of 14.72 mm reached by applying an eccentric load of 514 kN exceeds the allowable limit of 13.8 mm.

scholarly journals Influence of technical parameters on the structure of annular axis braided preforms

2021 ◽  
Vol 28 (1) ◽  
pp. 160-168
Author(s):  
Xi Wang ◽  
Guoli Zhang ◽  
Xiaoping Shi ◽  
Ce Zhang
Keyword(s):  
Cross Section ◽  
Rotation Speed ◽  
Technical Parameters ◽  
Braiding Angle ◽  
Shaped Cross Section

Abstract A modified vertical braiding machine and closed annular axis mandrels with a special-shaped cross section were used to braid annular axis preforms under four different technical parameters. After measuring the braiding angles and yarn spacing of the braided preform in different areas of the mandrels, it was found that the braiding angle increased by 20.9% and the yarn spacing decreased by 19.8% when the speed of the yarn carrier was doubled. The braiding angle decreased by 31.1% and the yarn spacing increased by 28.6% when the rotation speed of the mandrels was doubled. The results show that the rotation speed of the mandrel has a slightly greater influence on the braiding angle and the yarn spacing. By using the modified braiding machine to braid the annular axis preforms, multi-layer continuous braided preforms can be achieved on compact equipment. And the structure of the annular axis braided preforms can be changed by changing the technical parameters.

scholarly journals Hybrid Krill Herd-ANN Model for Prediction Strength and Stiffness of Bolted Connections

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 229
Author(s):  
Iman Faridmehr ◽  
Mehdi Nikoo ◽  
Mohammad Hajmohammadian Baghban ◽  
Raffaele Pucinotti
Keyword(s):  
Correlation Coefficient ◽  
Predictive Accuracy ◽  
Supply And Demand ◽  
Steel Structures ◽  
Ann Model ◽  
Krill Herd Algorithm ◽  
Seat Angle ◽  
Taylor Diagram ◽  
Krill Herd ◽  
Strength And Stiffness

The behavior of beam-to-column connections significantly influences the stability, strength, and stiffness of steel structures. This is particularly important in extreme non-elastic responses, i.e., earthquakes, and sudden column removal, as the fluctuation in strength and stiffness affects both supply and demand. Accordingly, it is essential to accurately estimate the strength and stiffness of connections in the analysis of and design procedures for steel structures. Beginning with the state-of-the-art, the capacity of three available component-based mechanical models to estimate the complex mechanical properties of top- and seat-angle connections with double-web angles (TSACWs), with variable parameters, were investigated. Subsequently, a novel hybrid krill herd algorithm-artificial neural network (KHA-ANN) model was proposed to acquire an informational model from the available experimental dataset. Using several statistical metrics, including the corresponding coefficient of variation (CoV), correlation coefficient (R), and the correlation coefficient provided by the Taylor diagram, this study revealed that the krill herd-ANN model achieved the most reliable predictive accuracy for the strength and stiffness of top- and seat-angle connections with double web angles.

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