International Journal of Steel Structures最新文献

The self-centering (SC) hysteretic damper can effectively enhance the seismic resilience of structures, due to its supplemental damping and recentering capability. Recently, a new SC damper, is developed known as the SC Disc Slit Damper (SC-DSD) was experimentally tested using cyclic loading test. In the proposed damper, the steel slit dampers play the role of energy dissipation (ED) source, while the pre-compressed disc spring stacks form the SC system. The tests have shown that the telescopic configuration of the damper ensures a symmetric cyclic behavior. However, additional analytical and finite element (FE) analyses are required to more deeply explore the effects of the damper's parameters and its local behavior. Based on the working mechanism of the damper, the restoring force models of the ED system and SC system are first derived individually, and then they are combined to obtain the hysteretic model of the damper. In addition, the FE model of the damper is established to provide additional information that is challengeable to observe in tests. The accuracy of the analytical method and FE model is confirmed by the testing results. Further, the parametric analysis is conducted based on the validated FE model, using the key parameters of the length of the steel strips, the width of the steel strips, and the preload of the stacked disc springs. Based on this work, the hysteretic behavior of the damper is further understood, and more importantly, it provides more insights for practical applications of the damper.

The steel rack upright is an essential member of the storage pallet rack system, which is made from mostly cold-formed thin-walled perforated steel profiles. Due to frequent storage and retrieval operations, pallet rack structures are likely subjected to accidental impact from forklifts or other material-handling robots. These impacts can cause local damage to the upright members, probably leading to the progressive collapse of the whole rack structure. In this paper, a physics and data-driven model is proposed for structure engineers to rapidly and quantitatively evaluate the upright local damage. First, finite element models of local bending damaged uprights are developed to accurately simulate the physical experimental results from the compression tests. It is shown that the corner damage of uprights is the most dangerous impact pattern compared to web damage and flange damage. Under certain special conditions, such as smaller upright sections and intermediate stiffeners, the upright with about 1 mm of local bending deformation at the corners can lead to an average decline of the carrying capacity up to 31.02%. Subsequently, a convolutional neural network (CNN) model is trained based on finite element method simulation data to predict the residual carrying capacity of damaged uprights quickly. The results obtained from the cases study indicate that the predicted values of CNNs are in good agreement with the FE numerical values, with mean absolute percentage error being 3.46%, which is a valuable decision-making tool for system engineers in the refined preventive maintenance of the automated storage and retrieval system.

The manufacturing error of steel truss members features significant randomness, which may result in discrepancies between the assembly accuracy of structural members on-site and the design specifications. This paper proposes an assembly accuracy analysis approach based on error propagation and stochastic simulation, constructing a theoretical framework for analyzing and quantifying the assembly accuracy under the influence of all uncertainty factors encountered during the assembly process. In addition, the reliability of assembly accuracy, i.e., the probability that the structural assembly accuracy on-site satisfies the designed specifications, is taken as a reasonable indicator for determining whether assembly on-site is feasible. First, develop error propagation models for a steel truss and clarify errors’ propagation and accumulation mechanisms. Then, identify uncertainty parameters and sample stochastically. Finally, create assembly limit-state functions and calculate assembly accuracy and corresponding reliability through the Monte Carlo simulation. Taking a flat and a spatial steel truss in practical engineering as an example, the results show that the assembly accuracy of the flat truss is 1.361 and 1.698 mm, and that of the spatial truss is 6.422, 6.927, 6.357, 7.346 mm, all above accuracy with 100% reliability. The sensitivity analysis results show that the rod length error plays an important role during flat truss assembly, and so does angular error during spatial truss assembly. The developed strategy is independent of the materials and structures applied. Therefore, it can be used for more complicated structures.

Flat-CSSWs (FCSSWs) have been introduced recently to enhance standard steal shear walls’ (SSWs) lateral behavior. The present paper studied the productivity of a two-layer SSW (SSW) system composed of a flat and corrugated plate with and without centrally-placed square opening under cyclic loading in the finite element Abaqus software. The results showed that adding central square openings decreased resistance, initial rigidity, and energy absorption. In general, owing to the opening, the maximum lateral resistance and energy intake have decreased by 31.4% and 45.9%, respectively. The maximum lateral resistance and energy absorption of FCSSWs have been achieved compared to flat SSWs. The difference between the maximum resistance and energy absorption of the two is 10.5% and 54.1%, respectively, which indicates the influence of the flat-corrugated system on the amount of energy absorption compared with the traditional flat SSW system. Also, despite severe pinching in the hysteresis curve of flat SSWs with and without an opening, the pinching phenomenon is not displayed in the hysteresis curve of FCSSWs with an opening. The average equivalent viscous damping in flat SSWs and FCSSWs is 31.77% and 39.35%, respectively. Also, raising the corrugated plate’s corrugation angle has increased the structural parameters. However, this increase is not significant. In addition to the fully connected FCSSWs samples to the boundary members, the investigation of the behavior of the beam-connected samples showed that the resistance and energy absorption in this system is between 13% and 14.2% compared to the corresponding samples with and without openings.

The closure process of a large-span steel roof directly determines the initial temperature effect during the service life of the structure and affects its internal force, particularly for parts with strong constraints. Therefore, it is essential to elucidate the influence mechanism of the stress response of large-span steel roofs for different closure processes and develop methods for closure optimisation in these structures. In this study, we proposed a novel method to determine the construction closure temperature of such structures by minimising in-service internal forces. Firstly, the surface temperature of the steel components was defined as the sum of the air temperature and temperature increase due to solar radiation. Subsequently, we determined the extremely high, extremely low, and annual average temperatures at the structure location. We then obtained the service temperature conditions of the structure by subtracting the construction closure temperature from these three temperature values. The structural response was subsequently simulated under various construction closure temperatures, and the relationship between the structural response and construction closure temperature was established, using the temperature corresponding to the minimum structural response as the construction closure temperature. Lastly, the proposed method was applied to the roof closure of the sub- and overall structures of the Shenzhen Bay Stadium. Subsequently, we evaluated the reaction reduction effect of the closure optimisation process on the constraint position of the bearings in the structure. The results indicate that the proposed method effectively reduces the influence range and degree of the construction process on the structural response during the service stage.

The loads applied to the structure have a considerable influence on the deformation of structures, for thin shells, because of their complex geometry and thin thickness. To avoid large deformations, stiffeners such as longitudinal or circumferential beams can be added to enhance rigidity. Nevertheless, numerical methods such as the finite element method (FEM) are necessary for examining these structures. Two types of finite elements (shell element + beam element) can be used to model the shell structure. However, there may be a compatibility problem at the intersection between the shell and the stiffener. To address this challenge, three-dimensional (3D) finite elements can be used to analyze the entire structure (stiffened shell) numerically. The numerical analysis of stiffened shells using a three-dimensional ABAQUS element (C3D8IH) is presented in this paper. Different types of structures were analyzed and the results obtained were compared with those derived from reference solutions found in the literature. This study confirms the efficiency of three-dimensional (3D) elements used in stiffened shell modeling and leads to very interesting conclusions for engineering application purposes.

This study determined the limit loads for API X60 pipe elbows subjected to in-plane bending moments in both opening and closing modes, while accounting for the effects of internal pressure. Load–deflection curves were analyzed to identify plastic collapse and instability loads at various pressure levels. The extended finite element method (XFEM) was used, incorporating a specialized elbow element to account for varying bend factors. The results indicated that theoretical equations are more conservative for closing moments compared to opening moments. Internal pressure significantly enhances load-bearing capacity, with a more pronounced effect as the bend factor increases. The Goodall equation remains conservative when combined with internal pressure and bending moments. Additionally, the study highlights pipe elbow geometry as a key factor influencing structural capacity, offering valuable insights for safer pipeline design.

A novel concrete-filled steel tubular section with diagonal strengthening bars was introduced in the current study. It is constructed from a circular steel tube with strengthening bars placed diagonally opposite from one top end to the bottom end. Analysis was done on specimens of diagonally stiffened concrete-filled steel tubular columns to determine the load-bearing capacity, load versus deformation behaviour, stress distribution, and failure pattern. A parametric study was also carried out to ascertain the impact of the steel casing's outer diameter and thickness, concrete strength, and stiffening scheme on the suggested concrete-filled steel tubular's behaviour. The current evaluation's findings indicate that the column sections'geometrical and material properties significantly impacted the uniaxial performance of concrete-filled steel tubular sections with diagonal stiffeners. Increasing the diameter and grade of diagonal stiffeners improved the peak loading capacity and load versus strain graph of concrete-filled steel tubular columns with diagonal strengthening bars. In addition, the design relations given by the current design standards were altered, and new design equations were used to predict the load capacity of concrete-filled steel tubular columns that were diagonally stiffened. The results showed that every updated design equation from the design codes was determined to be in good agreement with the outcomes of the analysis. With the recommended strengthening strategy, the amended Eurocode design equation results demonstrate a more accurate and consistent prediction of the load capacity of concrete-filled steel tubular columns.

This study focuses on the thermomechanical optimization of buckling resistance in laminated composite plate with a hole. The goal is to maximize the critical buckling load by identifying optimal fiber orientations within the layers using the Bonobo Optimizer Algorithm (BOA). The first-order shear deformation theory (FSDT) is employed to determine elastic buckling loads under combined thermomechanical loading. Numerical investigations are conducted for various parameters, including uniform temperature rises, edge loading conditions, support configurations, hole size ratios, load ratios, and geometric proportions. The results showed that these parameteres play a vital role in the the buckling load optimization of laminate composite plate with a hole. The study shows CCCC and SFSF boundary conditions yield the highest and lowest buckling loads, respectively. Critical buckling load decreases with temperature rise. Plates without cut-outs outperform those with cut-outs, and shorter plates under negative temperature rise achieve maximum buckling load. Uniform loading results in the lowest buckling capacity due to its larger loading area.

Detail drawings play an essential role in the steel structure manufacture as the basis for guiding manufacture and installation. Detail drawings are generally generated through software automatically nowadays. However, the current drawings created automatically by software are not of high quality, and the marks are overlapped, unattractive and unclear in the automatically generated drawings, which require considerable effort to manually adjust the position of the marks. In this paper, we developed an artificial intelligence algorithm for marks layout based on target detection algorithm. First, the marks layout problem is defined as the target detection problem. Then the Faster RCNN algorithm is refined on the basis of the unique characteristics of the marks layout problem, so that the algorithm is greatly strengthened in terms of accuracy and efficiency. It has been verified that after learning from the marks library, the marks generated by the proposed algorithm meet the requirements of manufacture. The aesthetics and clarity are significantly improved, and the workload of manual marks adjustment is dramatically reduced.