Improving the forming efficiency at a reasonable cost has been the main challenge in the electromagnetic forming technology. Towards this aim, this paper proposes a simultaneous cost-effective double-sheet electromagnetic forming method using single driving coil. In order to highlight the features of the proposed technique, comparison of the performance of five electromagnetic forming models is presented. These models include a no-sheet model, single-sheet stationary model, single-sheet moving model, double-sheet stationary model and double-sheet moving model. For each model, electromagnetic force distribution and forming efficiency of the workpiece are analyzed. Furthermore, the influence of the pulse current width of the driving coil on the electromagnetic forming efficiency of the plate is investigated for all models. Results show that for the same system discharge parameters, electromagnetic forming efficiency of double-sheet is 21.14% whereas the single-sheet electromagnetic forming model only achieves 14.68% efficiency. Thus, the double-sheet electromagnetic forming technology can improve the low forming efficiency of a single-sheet electromagnetic forming method and at the same time, the method can form two workpieces simultaneously which makes it more cost effective than the single-sheet method.

A steel Vierendeel sandwich plate used as a large-span lightweight floor structure for vibration comfort during crowd gatherings was considered. Taking the steel Vierendeel sandwich plate in Guizhou Museum as an example, through finite element transient analysis, the effects of the structural damping, pedestrian self-weight, floor span, surface concrete slab thickness, and structural parameters on the floor’s acceleration response distribution were deeply studied. According to the distribution characteristics of the acceleration response, a distribution model function was constructed, and a distribution Gauss model of the relationship between the peak acceleration response and the position of the steel Vierendeel sandwich plate was established. A field test of the sandwich plate under human-induced fixed-point excitation was carried out, and the model fitting results were compared with the actual test results. The results showed that the Gaussian model could effectively estimate the peak acceleration response at different positions on the floor. In addition, according to the distribution model, a comfort evaluation method based on the comfort assurance rate was proposed that could greatly reduce the representative value of the acceleration evaluation. The research results provide a reference for the comfort evaluation and corresponding vibration-reduction design of long-span steel Vierendeel sandwich plates.

In the conventional electromagnetic tube expansion, axial distribution of the electromagnetic force is not uniform along the workpiece. This results in uneven axial deformation of the deformed tube and restricts the full industrial implementation of this technology. In an attempt to overcome this issue, this paper proposes a new method based on dual-coil electromagnetic tube compression. In this regard, an electromagnetic-structure finite element coupling model is developed to emulate the real electromagnetic tube compression process. Influence of the proposed dual-coil structure parameters on the electromagnetic force distribution is analyzed. Results show that the proposed dual-coil electromagnetic tube compression method can effectively solve the problem of uneven axial deformation in the conventional electromagnetic tube compression. The proposed method is expected to promote wide industrial applications of the electromagnetic tube forming technology.

To balance the requirements of structural safety and economic efficiency in transmission tower design, this study proposes a structural optimization method based on an Improved Sparrow Search Algorithm (ISSA). Specifically, the methodology integrates Circle chaotic mapping to initialize the sparrow population distribution, followed by the introduction of a firefly perturbation strategy. This strategy updates the sparrow positions derived from the basic algorithm, thereby enhancing the algorithm’s ability to escape local optima. Based on these enhancements, a mathematical model for structural optimization is established with the primary objective of minimizing the total weight of the tower. The penalty function method is employed to handle constraints, while the finite element method is utilized for internal force analysis. To verify the effectiveness of the proposed approach, a typical cat-head transmission tower is selected as a case study. The optimization results obtained from the ISSA are compared with those produced by the Daoheng software, demonstrating a weight reduction of 3.79%. These findings indicate that the ISSA effectively improves the optimization performance and provides an efficient solution for the preliminary sizing design of transmission towers.