Design and experiment study on a novel magnetorheological impact damper coupled with multiple parallel relief orifices for reducing higher impact peaks

Conventional magnetorheological (MR) dampers exhibit the drawbacks of excessively large and non-adjustable peak force/acceleration during the initial impact in the context of high-impact loads, limiting their applicability in the field of impact resistance. This paper introduces an innovative MR damper (MRD), which, coupled with multiple parallel relief orifices, is capable of effectively mitigating the initial impact peak and enhancing the plateau effect during the mid and late stages of impact. Firstly, the configuration and principle of the novel MRD with multiple orifices (MRDWO) are illustrated and its nonlinear model, based on Bingham-Plastic model and accounting for minor loss, is established. Secondly, the structural design and fabrication of MRDWO were conducted. Simultaneously, for comparative purposes, a traditional MRD with an identical structure to MRDWO, except for the absence of relief orifices, was also fabricated. Then, experimental investigations were conducted separately on MRDWO and MRD without relief orifices (MRDWOO) under various impact velocities and control currents to study their damping forces, accelerations, and displacement responses. Finally, the experimental results of MRDWO were utilized to validate the reliability of the aforementioned nonlinear model. Additionally, a comparative analysis was conducted between MRDWO and MRDWOO under various operating conditions in terms of impact forces, accelerations, and displacements. The results indicate that the novel MRDWO significantly reduces the impact force/acceleration peak during the initial impact and enhances the plateau effect of force/acceleration in mid to later stages, thereby reducing the required displacement for absorbing. This is crucial for mitigating the initial impact damage and improving the damping efficiency of the MR damper.