Design, development and characterization of novel multi-layer multi-pole hybrid radial flux MR damper for vehicular application

Magneto-Rheological (MR) fluid exhibits rapid and controllable change in rheological properties under applied magnetic field, making it suitable for semi-active damping systems. This study presents design, development and performance of optimized multi-layer multi-pole hybrid radial flux MR damper using in-house prepared MR fluid sample, with carbonyl-iron-particles, silicone oil and guar-gum. Through characterization, MR fluid exhibited strong field-dependent behaviour, showing rise in yield stress and viscosity with increasing current input, utilized for damper design. Conceptual design of novel MR damper was subjected to magneto-static analysis using ANSYS software to achieve effective combination of radial-axial magnetic flux across MR fluid gap. Comprehensive design optimization study was then carried out using factorial L27 array, considering six design parameters and three key responses. Optimized damper was fabricated and experimentally evaluated under various frequencies and current levels, showing consistent increase in damping force with magnetic excitation. Modified Bouc–Wen model is used to formulate mathematical model based on measured experimental force–displacement loops while current dependent relations for all model parameters were established and integrated into quarter car model for dynamic studies subjected to random road irregularities as per ISO 8608 standard along with skyhook control. Results demonstrated significant vibration reduction upto 73% under skyhook control compared with passive state. Further, the simple Skyhook control logic implemented in the present study can be considered for future real-time implementation in automotive suspension systems.