Welded Beams Research Articles

Hybrid Strategies Based Seagull Optimization Algorithm for Solving Engineering Design Problems

The seagull optimization algorithm (SOA) is a meta-heuristic algorithm proposed in 2019. It has the advantages of structural simplicity, few parameters and easy implementation. However, it also has some defects including the three main drawbacks of slow convergence speed, simple search method and poor ability of balancing global exploration and local exploitation. Besides, most of the improved SOA algorithms in the literature have not considered the drawbacks of the SOA comprehensively enough. This paper proposes a hybrid strategies based algorithm (ISOA) to overcome the three main drawbacks of the SOA. Firstly, a hyperbolic tangent function is used to adjust the spiral radius. The spiral radius can change dynamically with the iteration of the algorithm, so that the algorithm can converge quickly. Secondly, an adaptive weight factor improves the position updating method by adjusting the proportion of the best individual to balance the global and local search abilities. Finally, to overcome the single search mode, an improved chaotic local search strategy is introduced for secondary search. A comprehensive comparison between the ISOA and other related algorithms is presented, considering twelve test functions and four engineering design problems. The comparison results indicate that the ISOA has an outstanding performance and a significant advantage in solving engineering problems, especially with an average improvement of 14.67% in solving welded beam design problem.

Experimental and numerical investigation on residual stress and deformation of welded I-section curved steel beams

This paper presents an experimental and numerical investigation on welding-induced residual stresses and deformations of in-plane curved welded I-section steel beams. Two welded curved beams with different curvatures were investigated. After welding the curved beam, the residual deformations were measured by a 3D scanner. The residual stresses were subsequently obtained through a high-precision sectioning method. The effects of curvature on the magnitude and distributions of residual deformations and stresses at the specific sections were analysed with the test results. It was found that the residual deformation gradually increased from the weld region to both ends of the flange plate, and the torsion in the web plate became severe with a decrease in curvature of the curved beam. Moreover, the welding process of the curved beam was simulated using the finite element (FE) method. The developed FE model was validated against the test results, and thereafter, parametric analyses were conducted to assess the influence of welding sequence, welding speed, and curvatures of the curved beam on the welding residual stresses and deformations. The numerical results demonstrated that the residual stresses and deformations were significantly influenced by welding speeds, but the influence from curvature of the curved beam was relatively small. Finally, a reasonable welding sequence, welding speed, and curvature of the curved beams were recommended.

Hybrid Bird Mating Optimizer for Welded Beam Design Optimization Problem

This study introduces a hybridization of the Bird Mating Optimizer (BMO) with Differential Evolution (DE). The Bird Mating Optimizer exhibits certain limitations, such as a slow convergence rate and a tendency to become trapped in local optima. To address these issues, a new method, BMO-DE, is proposed to enhance the performance of the BMO swarm intelligence algorithm. BMO-DE is a versatile swarm intelligence algorithm applicable to various engineering problems. In this research, it is specifically employed in the optimization of welded beam design, a type of problem characterized by numerous constraints. The penalty function approach is used to handle the constraints associated with welded beam design. Comparative analysis indicates that the proposed BMO-DE method outperforms other swarm intelligence algorithms in tackling this category of problems. Notably, the method demonstrates efficacy in finding optimal solutions with a low number of objective function evaluations, making it a potent and promising approach for addressing such problems.

Optimization of Welded Beam Design Problem Using Water Evaporation Optimization Algorithm

This paper introduces a novel approach to tackle the Welded Beam Design Problem through the application of the Water Evaporation Optimization Algorithm (WEOA), a nature-inspired metaheuristic. The problem involves finding the optimal dimensions of a welded beam that can support a given load while minimizing its weight. The Water Evaporation Optimization Algorithm draws inspiration from the evaporation process and water droplet movement in nature. The design is formulated as an optimization challenge with beam dimensions as variables and incorporate constraints such as allowable stress and geometric limitations. The fitness function is tailored to evaluate each candidate solution based on load-bearing capacity and weight. To demonstrate the efficacy of the proposed method, extensive experimental evaluations are conducted. Comparisons with traditional optimization techniques highlight the WEOA's superior convergence and global search capabilities. Real-world case studies further illustrate the practical applicability of the optimized welded beam designs, showcasing their cost-effectiveness and high-performance characteristics. The results underscore the potential of the Water Evaporation Optimization Algorithm as a robust and efficient tool for tackling the welded beam design problem. The approach provides engineers with valuable support in achieving optimized beam designs, leading to improved structural performance and material utilization.

Numerical modelling and design of normal and high strength steel non-slender welded I-section beam–columns

This paper presents a comprehensive numerical study into the in-plane member stability and design of normal and high strength steel (NSS and HSS) non-slender welded I-section beam–columns subjected to compression plus uniaxial bending. Finite element (FE) models were firstly developed to replicate the structural performance of welded I-section beam–columns made of different steel grades, as observed in existing tests collected from the literature. The validated FE models were then employed in a comprehensive parametric study to generate extensive numerical data covering a wide range of cross-section geometries, steel grades, member slendernesses and loading combinations. The numerically obtained data were utilised to evaluate the accuracy of the current design methods set out in the European Standards EN 1993-1-1:2005 and EN 1993-1-12:2007 as well as the American Specification AISC 360-16 for both NSS and HSS non-slender welded I-section beam–columns. The comparisons revealed that the codified design methods yield varying levels of accuracy in predicting the ultimate capacities of welded I-section beam–columns depending on the steel grade. To address this issue, new design proposals that are compatible with the European beam–column design framework have been developed, featuring more accurate yield strength-dependent interaction curves anchored to improved resistance predictions for members subjected to isolated loading scenarios (i.e. the compression and bending end points of the interaction curves). The new design proposals have been found to provide more accurate and consistent resistance predictions than the existing codified design provisions for NSS and HSS non-slender welded I-section members under compression plus uniaxial bending. The reliability of the new proposals has been confirmed through statistical analyses according to EN 1990: 2002.

Effects of state‐of‐the‐art residual stress models on the member and local stability behaviour

AbstractResidual stresses have considerable effect on both the local and the member stability behaviour of steel structures. Previous studies have shown that the structural stability behaviour depends on both the distribution and the amplitude of the residual stresses. The residual stress distribution is affected by the cross‐section geometry, the steel grade and the manufacturing process, e.g. flame cutting and the welding procedure. A realistic consideration of residual stresses is necessary for an efficient and safe design of steel structures.This article presents an experimental and numerical study on the influence of residual stresses on the stability behaviour of structural members, i.e. steel columns and beams considering a variety of cross‐sectional slenderness, i.e. plastic, compact and slender cross‐sections are taken into account. A novel residual stress model for welded I‐shaped sections was developed and evaluated using test data. This model takes into account the main influencing parameters, i.e. the cross‐sections geometry, the steel grade as well as manufacturing process with thermal cuts or non‐thermal cuts of the steel plates. The novel residual stress model is then used to investigate the stability behaviour in terms of a numerical simulation study. The result of the study allows to propose an improvement of the buckling curve selection for welded high strength steel columns and beams.

Local buckling and hysteretic behavior of Q690 high-strength steel box-section beam–columns

High-strength steel structures have favorable mechanical properties and perform economically, but their application in seismic design is limited owing to their poor deformation capacity. In order to evaluate the hysteretic performance of Q690 high-strength steel box-section beam–columns and to assess the rationality of applying Eurocode 3 (EC3) to classify cross-sections of high-strength steel, three non-thin-walled welded box-section beam–columns were designed, and horizontal cyclic loading tests under constant axial force were undertaken. The hysteretic response of the specimens was analyzed from the standpoint of the failure mode, the degree of plastic evolution in the cross-section, energy dissipation capacity and ductility. Following this, numerical models verified from the experimental results were used for a parametric analysis to obtain the hysteretic response over a wider range of variables. The test results show that the local buckling failure of the plate at the base of the beam–column determines the failure mode of all three specimens. For a low axial compression ratio, a section with small width to thickness ratio may experience fracture. The parameter analysis showed that there is a flange-web interaction, and the evolution of cross-section plasticity under axial force is also related to the plate width to thickness ratio. In addition, through an analysis of the degree of plasticity in the cross-section under different parameter combinations, it is found that the classification of high-strength steel box-sections by the current specification is not rational, and that EC3 may be unreliable for 690 MPa box-section columns with Class 1 and Class 2 cross-sections, especially with a large axial compression ratio. A new cross-section classification method suitable for high-strength steel columns considering the influence of web-flange interaction and axial compression should be explored.

A Novel Residual Stress Model for Welded I‐sections and the Influence on the Stability Behaviour

AbstractResidual stresses have a marked influence on the stability behavior of steel members. Previous studies have shown that the structural behavior depends on both the distribution and the size of residual stresses. The residual stress distribution is affected by the cross‐section geometry, the steel grade and the manufacturing process, e.g. flame cutting and the welding procedure. A realistic consideration of residual stresses is necessary for economic models for design purposes and a safe design of steel structures.This paper presents an experimental and numerical study on the influence of residual stresses on the stability behavior of structural members, i.e. steel columns and beams. A novel residual stress model for welded I‐shaped sections was developed and evaluated using test data. This model takes into account the main influencing parameters, i.e. the cross‐sections geometry, the steel grade as well as manufacturing process with thermal cuts or non‐thermal cuts of the steel plates. The novel residual stress model is then used to investigate the structural stability behavior in terms of a numerical simulation study. The result of the study allows to propose an improvement of the buckling curve selection for welded high strength steel columns and beams.

Deflection analysis of welded steel I‐girders with corrugated webs based on first yield

AbstractSinusoidal corrugated profile webs have been popularly used in steel structural designs to replace the flat webs in conventional welded beams, while there are better performances in corrugated web beams (CWBs) regarding more stability and less material used to against beam failures caused by buckling. Previous studies have provided that CWBs enabled numerous favourable benefits to be recognised as alternatives to the traditional weld beams in designing structures. Furthermore, as CWBs are proposed as the major load‐carrying elements, the maximum deflection in the elastic range is one of the important beam properties that should be precisely estimated and calculated. To find an appropriate method in computing the maximum deflection of CWBs based on the first yield for civil communities in Australia, proposed equations based on other standards will be employed to calculate the theoretical results for the comparisons with simulation‐based results. While applying the linear analysis simulations provided by SAP 2000, ultimate limit state design theory has also been used with requirements stated by AS 4100. In this study, the results in theoretical calculations and numerical simulations have been compared to conclude that the highly defined equations by ASTM [37] and Sause et al. [38] could precisely estimate the maximum deflections of CWBs based on the first yield in conjunction with requirements and limitations in Australian standards, which could be adequate for the structural design calculations in Australian design fields.

Flange Local Buckling Resistance and Local–Global Buckling Interaction in Slender-Flange Welded I-Section Beams

AISC Specification Chapter F characterizes the flange local buckling (FLB) strength of I-section members having a slender compression flange as the theoretical elastic plate local buckling resistance, ignoring beneficial local post-buckling strength. Previous research has shown that this results in highly conservative strength predictions for slender-flange members. Additionally, potential interaction between local and global lateral-torsional buckling modes is not considered in the AISC Specification. These aspects can be important in applications involving the use of slender-flange members. This paper investigates a number of potential methodologies to account for local post-buckling strength as well as local–global buckling interaction in beams having slender flanges. A parametric finite element analysis (FEA) study is conducted considering a range of I-section members. The strength predictions from the proposed methodologies and the AISC Specification are evaluated against the FEA results as well as against a database of measured strengths from previous experimental tests of I-section beams governed by FLB. Recommendations are provided focusing on simplicity of the calculations and the efficacy of their predictions.

S960 ultra-high strength steel slender welded I-section beam–columns: Testing, numerical modelling and design

This paper presents experimental and numerical investigations of the buckling behaviour and resistance of S960 ultra-high strength steel slender welded I-section beam–columns under combined compression and minor-axis bending moment. An experimental programme, including initial geometric imperfection measurements and eight beam–column tests, was firstly conducted. The test procedures, setups and results were fully reported. Following the experimental programme, a numerical modelling programme was carried out, with finite element models initially developed and validated against the test results and then employed to conduct parametric studies to generate further numerical data. On the basis of the test and numerical data, the relevant design interaction curves, as provided in the European code, Australian standard and American specification, were evaluated for their applicability to S960 ultra-high strength steel slender welded I-section beam–columns. The evaluation results revealed that all three codified design interaction curves lead to conservative resistance predictions, mainly owing to the conservative end points (i.e. column buckling strength and cross-section minor-axis bending resistance). Finally, a revised Eurocode design interaction curve, with improved compression end point determined from more accurate column buckling curve and bending end point determined from the direct strength method, was finally proposed, and shown to result in more accurate resistance predictions for S960 ultra-high strength steel slender welded I-section beam–columns than the codified design interaction curves.

Structural behaviour and continuous strength method design of high strength steel non-slender welded I-section beam–columns

This paper presents the development of efficient design equations for high strength steel (HSS) welded I-section beam–columns under the framework of the Continuous Strength Method (CSM). The present work includes a collection of available experimental data on HSS S690 and S960 welded I-section beam–columns and a comprehensive numerical modelling programme considering a wider spectrum of parameters that influence the structural behaviour of the HSS welded I-section beam–columns. The developed FE models were first validated against test results collected from the literature, after which parametric studies were performed to generate further results to assess the accuracy of the codified design methods as used in Europe and the US, as well as to underpin new design proposals for HSS non-slender welded I-section beam–columns. It has been shown that the proposed CSM-based design approach is able to provide reliable design predictions with improved accuracy and reduced scatter over the existing design methods, and its reliability has been confirmed by means of statistical analyses.

МАТЕМАТИЧНЕ МОДЕЛЮВАННЯ ОПТИМІЗАЦІЇ ПОКРИТТЯ КРУГЛОЇ У ПЛАНІ БУДІВЛІ З РАДІАЛЬНИМ РОЗТАШУВАННЯМ БАЛОК

The article presents the results of optimization of the angle between radial beams in the floor of a circular building in the plan. On the one hand, they rest on the central post, and on the other, on vertical supporting structures along the circle. Steel decking is laid on the beams. The angle between the beams is determined so that the mass of the beam and the deck is minimal. This angle is considered optimal. To solve the problem, the target function of the cost of flooring and radial beams per unit floor area is used. This function depends on the angle between the beams. Using mathematical methods of differentiation, the minimum of the objective function and the corresponding value of the optimal angle were found. The thickness of the flooring was determined on the basis of ensuring its rigidity. It is assumed that composite welded radial beams have I-beams with two axes of symmetry. The height of the beam corresponds to the equality of the areas of the shelves and the wall. The problem of determining the optimal angle between the beams was solved on the basis of ensuring the strength of the beams under normal stresses. In the design diagram of the beam, a triangular distributed load is adopted. The dimensions of the cross-section of the beam were determined based on the equality of the required and actual moments of resistance, and were included in the target cost function. The study took into account that the deflection of the beam at the optimal angle between them can exceed the limiting standard value. Based on the solution of the system of equations of strength and stiffness, a formula is obtained for the minimum angle between the beams from the stiffness condition. The carried out mathematical studies have shown that at the optimal angle between the beams, it is possible to ensure its rigidity. This is possible when the flexibility of the beam wall exceeds a certain minimum value. Analysis of the formula for the minimum value of the wall flexibility showed that it is proportional to the design steel resistance to the sixth power. Therefore, to ensure that the deflection of the beam does not exceed the limiting value at the optimum angle, it is necessary to use low strength steel. To confirm the practical feasibility of using the proposed method, the problem was solved with certain numerical data. The results obtained have confirmed that the problem has a practical meaning at a relatively low steel strength. In addition, it turned out that the optimal angle between the beams does not depend on its span.

Calculation of the improved steel beams of buildings and structures of the mining and metallurgical complex

Load-bearing elements of buildings and structures of the mining and metallurgical complex in recent decades need to develop new more effective design solutions due to the intensification of technological processes, an increase in temperature loads and aggressiveness of the environment. The main direction of increasing the efficiency of such elements is their design from economically alloyed steel, which allows to increase the resource of structures and prevent accidents with a significant increase in temperature. Due to the fact that alloyed steels have higher mechanical characteristics at elevated temperatures, the question arises of creating lightweight beam structures from such steels, reducing their material consumption while maintaining the stability and fatigue strength of beams, the most promising is the use of welded beams with a perforated wall and composite beams.
 The creation of the most effective cross-sectional shape of metal beams with a perforated wall and welded beams, as well as crane beams in transverse bending, considering strength, local stability, flat bending stability and fatigue strength is considered. It is shown that an effective shape of beams with a perforated wall is a box-shaped structure made of perforated channels. A calculation was carried out to select a rational design made of an assortment of hot-rolled channel profiles. It is shown that due to the use of the proposed sectional shape, significant savings in the weight of the structure can be achieved. Considering the three-dimensional stress-strain state, the fatigue strength of welded metal crane girders operating in severe conditions is estimated. The efficiency of using a hot-rolled I-beam as the upper chord of such welded beams is shown. The necessity of using a hot-rolled I-beam and to ensure the fatigue strength of the lower chord is demonstrated.
 The use of the previously proposed combined method for calculating the structures of industrial buildings and structures and the use of economically alloyed steels allows us to create new designs of critical elements that reduce their material consumption and increase their resource. Further research can be carried out for real object designs in order to reduce their cost and increase reliability during operation in the conditions of mining and metallurgical production.

Numerical Investigation on Shear Deflection of Steel Welded I Sections with Varying Span to Depth Ratios

Deflection of the steel I-sections is an important phenomenon that needs to be taken into account to ensure that the serviceability limit state criteria of the Australian Standards are met. The method that is widely used to calculate the deflection of steel I-sections is by the use of existing formulae that only accommodate the bending stiffness of the beams. A numerical investigation is performed in this study to find the contribution of shear effects in the final deflection of the Welded-Beams (WB) and Welded-Columns (WC). The numerical analyses were carried out in SAP2000 and numerical model was first validated using the experimental results of welded plate girders. The model was then used to analyse simply supported WB and WC sections under uniformly distributed load (UDL) with varying span lengths. The results of the numerical analyses are reported in this study which compare the mid-span deflection values from the simply supported deflection formula with the numerical model deflection values. The data acquired from the numerical analyses were used to establish a span to depth ratio for WB and WC sections below which the shear deflection becomes significant. The analysis of the results obtained from the numerical investigation suggests that a predication error begins to emerge in the result that is acquired from flexure deflection formulae at a certain span-depth ratio.

Flexural strength and rotation capacity of welded I-section steel beams with longitudinally profiled flanges

Application of longitudinally profiled (LP) steel plate in the flange of flexural members may provide a good solution to optimize their mechanical performance and to improve the efficiency of steel use, whilst existing design codes provide no design guidance or prediction methodology for such advanced beams in terms of flexural behaviour. To clarify their flexural strength and rotation capacity, tests on two full-scale welded I-section steel beams with longitudinally profiled flanges (LPB members) are carried out herein, as well as two traditional beams with uniform cross-section for comparison. All the specimens exhibit sufficient flexural strength and rotation capacity for seismic plastic design, and specifically, the LPB members possess even better performance in case of identical steel usage. Parametric analyses of 250 beams incorporating a wide range of flange slenderness and steel grades, are conducted by employing the validated nonlinear FE model to investigate the effects of rate of thickness change for the LP flanges. The results show that the effect is limited on the flexural strength but significant on rotation capacity. The existing design provisions for beams with uniform cross-section give generally conservative design results for the flexural strength of the LPB members, but limiting values of flange slenderness needs to be reduced. The research outcomes may provide an important basis for promoting the application of LP plates in flexural members.

OPTIMISATION OF WELDED BEAMS: HOW COST FUNCTIONS AFFECT THE RESULTS

AbstractThe increasing market competitiveness and CAE availability require the products to be optimised. This practice is exceedingly present when producing semi-standard parts like structural elements. Several cost calculation methods are developed, bringing up the question - which one to use? In this article, we compared three methods; a welded I-section beam was used as an example. The optimisation was carried out using two objectives (mass and cost) and was submitted to Eurocode boundary conditions. The results have shown that the cost calculation method has a negligible influence on the results.

Multi-objective orthogonal opposition-based crow search algorithm for large-scale multi-objective optimization

Many engineering optimization problems are typically multi-objective in their natures and multidisciplinary with a large number of decision variables. Furthermore, Pareto dominance loses its effectiveness in such situations. Thus, developing a robust optimization algorithm undoubtedly becomes a true challenge. This paper proposes a multi-objective orthogonal opposition-based crow search algorithm (M2O-CSA) for solving large-scale multi-objective optimization problems (LSMOPs). In the M2O-CSA, a multi-orthogonal opposition strategy is employed to mitigate the conflicts among the convergence and distribution of solutions. First, two individuals are randomly chosen to undergo the crossover stage and then orthogonal array is presented to obtain nine individuals. Then individuals are used in the opposition stage to improve the diversity of solutions. The effectiveness of the proposed M2O-CSA is investigated by implementing it on different dimensions of multi-objective optimization problems (MOPs). The Pareto front solutions of these MOPs have various characteristics such as convex, non-convex and discrete. It is also applied to solve multi-objective design applications with distinctive features such as four bar truss (FBT) design, welded beam (WB) deign, disk brake (DB) design, and speed reduced (SR) design, where they involve different characteristics. In this context, a new decision making tool based on multi-objective optimization on the basis of ratio analysis (MOORA) technique is employed to help the designer for extracting the operating point as the best compromise or satisfactory solution to execute the candidate engineering design. Simulation results affirm that the proposed M2O-CSA works efficiently and effectively.

NEW STEEL‐TIMBER COMPOSITE BEAM, NORDIC SYSTEM

AbstractThe design of new steel‐timber composite beam, called Nordic system, is proposed. The beam consists of CLT (Cross Laminated Timber) slabs that are installed on the bottom flanges of an asymmetric welded steel box. The composite action is achieved through connection the slabs to the steel beam by steel plates which are screwed to the timber and bolted to the top flange of the beam. The composite action reduces the stresses of the steel beam compared to the pure steel beam without composite action. This means that there exists a large potential to search lightweight, dry slim floor, low emission and cost optimal solutions using this composite beam due to large variations for available steel grades of the welded beam, as has been shown previously for pure welded steel beams.

Structural Behaviour and Mechanical Properties of Welded Steel I-Girders with Corrugated Webs

Steel I girders with corrugated webs are appropriate alternatives for normal flat-web girders in steel structures since they provide lighter and smaller beam features in steel design. Based on the existing literature, the corrugated web beams (CWBs) provide many advantages for structural applications. In this study, a series of numerical analyses have been performed in order to investigate the structural behaviour of steel I girders with corrugated web profile and to compare their mechanical performance with normal welded beams. Theory of Ultimate Limit State design has been adopted in accordance with AS4100 (Steel structures, Standard Australia, Sydney, 1998) along with considering geometric and material non-linearity in the numerical analyses in SAP2000. Comparing the results of the numerical investigation, merits of using corrugated welded beams (CWBs) over normal welded beams (WBs) have become apparent. Moreover, investigations regarding force–displacement relationship and buckling analysis of the webs were carried out and presented to further validate the advantages of using corrugated web beams. CWBs have been used in some parts of Australia without detailed information about their mechanical properties. Thus, based on the outcomes of this study, CWB table for dimensions and cross sectional properties has been developed and proposed for practical applications.