Experimental study and load control of concentric electromagnetic damper under intensive impact load

Background: Conventional electromagnetic dampers impose a bias torque on artillery systems, which adversely affects system stability and performance. Objective: This study aims to propose a novel concentric electromagnetic damper (C-EMD). Based on the principle of electromagnetic induction, it achieves efficient braking to effectively eliminate the aforementioned bias torque effect. Methods: First, a nonlinear dynamic model of the C-EMD was established through theoretical analysis, finite element simulations, and impact experiments. This model was used to analyze the mechanism by which magnetic flux density affects damping performance and the parameter influence patterns. Subsequently, parameter sensitivity analysis was conducted using Optimal Latin Hypercube Design (OLHD) and polynomial regression methods. Finally, a surrogate model based on elliptic basis neural networks was developed, and multi-objective optimization was performed by integrating multi-island genetic algorithms with nonlinear programming by quadratic lagrangian. Results: Modeling analysis revealed that the resultant resistance curve exhibits a saddle-shaped profile with a concave center and elevated ends. Parameter sensitivity analysis results showed that liner thickness and air gap thickness have the most significant impact on performance (contributions >26%), while the influence of outer tube thickness is minimal (only 0.83%). Post-optimization results demonstrated: a reduction in resultant resistance curve flatness to 1.42, an increase in fill ratio to 89.86%, a 4.63% decrease in maximum displacement, and near-complete elimination of the saddle-shaped characteristics. Conclusions: This research provides an innovative solution for enhancing electromagnetic damper performance, with significant practical implications.