Implementation and Numerical Validation of a Semi-Active Tuned Mass Damper for Vibration Mitigation in Lightweight Pedestrian Structures

Experimental and simulation-based optimization of semi-active suspensions using magnetorheological dampers

The dynamic behavior of heavy vehicles is significantly influenced by suspension design, which governs both ride comfort and road-holding characteristics. Conventional passive suspension systems exhibit inherent limitations in isolating the vehicle from road-induced vibrations, especially under high-speed operating conditions. To address this issue, the present study developed a comprehensive bond-graph-based dynamic model of a semi-active suspension system integrated with a magnetorheological damper. The model is experimentally validated using a quarter-car test rig, capturing the nonlinear hysteretic response of the magnetorheological damper through a modified Bouc–Wen formulation. Simulation results are compared with the measured data to confirm model accuracy across varying excitation frequencies and input currents. Subsequently, the response surface methodology is applied to determine the optimal configuration of suspension parameters, namely spring stiffness, damper current, tire stiffness, and tire pressure, to achieve enhanced ride comfort and road-holding. An optimized ride comfort value of 0.679545 m/s 2 and an optimized road holding value of 21.81 mm were obtained with a corresponding desirability value of 0.785. The proposed methodology effectively integrates analytical modeling, experimental validation, and optimization to evaluate and enhance the performance of heavy vehicle suspension systems.

Study on Parameter Optimization of a Multi-Mass Pendulum for a Wind-Induced Vibration Control System

The tuned mass damper (TMD) exhibits good performance in suppressing wind-induced vibrations of high-rise structures. However, a single TMD has a limited control bandwidth and poor robustness. The multiple-pendulum tuned mass damper (MPTMD) offers advantages, such as a wider control bandwidth, stronger robustness, and a simple structural configuration, while its working frequency can be easily adjusted by varying the pendulum lengths. With two optimization objectives, namely displacement and acceleration, this study derives the displacement and acceleration dynamic amplification factors of the primary structure equipped with the MPTMD under external excitation and examines the interrelationships among the optimal parameters and their underlying mechanisms. The accuracy of the proposed optimization method and the effectiveness of the MPTMD are validated by fitting the theoretically derived optimal parameter curves with results from numerical simulations. Finally, the control performance of MPTMD and TMD is compared through a numerical example subjected to realistic wind load excitations, verifying the control effectiveness of MPTMD. Nevertheless, several limitations should be acknowledged. The present optimization is based on a single-degree-of-freedom (SDOF) primary structure and targets only the first translational mode; the effects of higher modes and multi-degree-of-freedom (MDOF) coupling are not considered. Additionally, the wind load is represented by a synthetic time history with a fixed return period, and uncertainties in real wind fields are not fully addressed. Future work should extend the proposed method to multi-modal control, nonlinear behavior, and experimental validation.

Dynamic modelling and adaptive vibration control strategy for rotor systems with elastic support–dry friction damper

Performance-oriented design of overload-protected viscous dampers for adjacent structures

The application and performance-oriented parameter optimisation of an overload-protected viscous damper (OP-VD) are investigated in this study to mitigate seismic responses and prevent excessive force transmission between adjacent structures. Within a performance-based seismic design framework, the damper parameters are systematically optimised to ensure that multiple response objectives are satisfied under varying seismic intensities. The OP-VD integrates a frictional overload protection mechanism with viscous energy dissipation, enabling an adaptive control strategy. This design ensures that damper forces are effectively capped under strong ground motions, while sufficient damping is provided under moderate excitations to control inter-storey drift and absolute structural acceleration. The mechanical characteristics and working principle are first clarified through detailed implementation and simulations. Subsequently, a coupled dynamic model of adjacent structures interconnected by the proposed damper is established for non-linear time-history analyses. Numerical simulation results demonstrate that under severe seismic inputs, the OP-VD successfully limits force transfer by way of the activation of the overload protection mechanism, thereby preventing structural overloading. In contrast, under moderate excitations, the viscous component dominates, leading to enhanced vibration attenuation. Consequently, the device achieves a balanced control of drift, acceleration and force demands, ensuring both structural safety under rare earthquakes and serviceability under frequent events.

Design and Experimental Study of a Semi-Active Boom Vibration Damping System for a Shielded Soybean-Maize Sprayer

For the problem that, under the soybean-maize strip intercropping pattern, the installation of anti-drift shields changes the mass and inertia characteristics of the boom of a shielded sprayer, making it prone to severe vibration under complex field excitations and thereby affecting application uniformity and operational safety, a semi-active boom vibration damping system based on a magnetorheological damper was designed and tested. First, an equivalent mechanical model of the boom considering added mass and stiffness variation was established, and the characteristics of excitation sources such as road spectra and start-stop impacts were clarified. Second, based on the Bouc–Wen model, the magnetorheological damper was selected and its output force boundaries were designed. The stroke was determined to be 80–110 mm, and the maximum damping forces in the compression and rebound strokes were 1.15 kN and 3.44 kN, respectively. Furthermore, a semi-active vibration damping system with an LK3U-14MT PLC as the core controller was developed. Finally, simulation analysis, free-vibration decay tests, obstacle-crossing tests, and field operation tests were conducted to verify the vibration damping performance of the developed semi-active system. The field test results showed that, at typical operating speeds of 3–5 km/h, the semi-active vibration damping system reduced the maximum vertical amplitude at the boom tip by 28.6–43.1% and the maximum inclination angle by 12.2–55.6%, effectively improving the attitude stability and roll resistance of the boom of the shielded sprayer.

Analysis and design of high-rise steel buildings with semi-active dampers

The growing need of the high-rise steel buildings in the fast-developing urban areas has led to the introduction of the new and improved structural control systems that focus on the safety, serviceability and comfort of occupants during the dynamic loading conditions. Such structures are easily vulnerable to vibrations and seismic forces caused by the wind and can result in uncontrolled movement, inter-storey drift and structural damage due to their slenderness and flexibility. This paper provides a detailed literature review on semi-active damping system and how this system can be used in the analysis and design of high-rise steel structures. This paper summarizes the results of recent studies on fluid viscous dampers, tuned mass dampers, magnetorheological dampers, and hybrid control systems. The focus is on semi-active tuned mass dampers (SATMDs), which have adaptive performance, as they modify the damping properties on-the-fly with minimal energy use. The review shows that optimization techniques, control algorithms, and soil-structure interaction are important in improving the efficiency of the damper. Comparative studies reveal that semi-active systems are more effective than the traditional passive devices in damping vibration, displacement, and acceleration, and more robust to the current circumstances of diverse loads. In addition, life-cycle cost analysis shows that such systems are economically and structurally beneficial in the long run even though they are more expensive to purchase. On the whole, semi-active dampers integration is a major contribution to the current structural engineering, which adds to the resilience and sustainability of tall buildings design along with high performance.