Rotationally Tunable Permanent Magnet Magnetorheological Damper for Stepless Damping Control: Magnetic Modeling and Experimental Validation

Magnetorheological (MR) dampers, leveraging the intelligent rheological properties of MR fluids, have been widely applied in vibration control systems across civil engineering, mechanical engineering, and aerospace. However, conventional coil-driven MRDs suffer from inherent limitations such as Joule heating, current-regulation delays, discrete damping adjustment, high energy consumption, and complex architectures. To address these challenges, this paper presents a novel rotationally adjustable MRD utilizing permanent magnets (PMs) to generate the magnetic field, enabling stepless damping modulation via magnetic flux density control. The damper’s cylindrical single-tube piston structure was first designed, incorporating a radial-magnetized NdFeB PM core and symmetric damping channels. Magnetic field analysis was conducted using analytical models and COMSOL simulations, demonstrating a 95% consistency in flux density predictions. A hybrid mechanical model integrating shear and valve modes was developed to quantify the damping force, revealing an adjustable range of 60–90% of the maximum output with an optimal damping channel angle of [Formula: see text]. Experimental validation of the fabricated prototype showed over 97% agreement with model predictions, confirming precise stepless adjustment without power supply. This design offers a compact, portable, and reliable solution for low-power vibration control applications, highlighting significant scientific and engineering value.