A magnetorheological vibration absorber with bidirectional tunability for pipelines

Abstract

Magnetorheological elastomer (MRE) had been employed as a tunable stiffness element in dynamic vibration absorber (DVA) due to its remarkable magnetic tunability. However, the natural frequency of MRE-based DVA could only be tuned towards high frequency under magnetic fields, which failed to solve or even exacerbate the low-frequency pipeline vibration. To tackle this issue, an innovative DVA (H-DVA) with bi-directional magnetic tunability was proposed in this paper. The hard magnetic MRE filled by NdFeB particles was selected as the core tunable stiffness element in H-DVA. Besides, the discretization distribution design scheme for the mass oscillators was adopted to improve the flexibility of H-DVA. Then, the magnetic field simulation and resonance frequency shifting test of H-DVA under different magnetic fields were completed to validate the bi-directional magnetic tunability. Lastly, the vibration absorption effect was verified in a self-established experimental pipeline system. The experiment results demonstrated that the resonance frequency of the proposed H-DVA exhibited a maximum frequency shift of approximately -2.7Hz under reversed magnetic field. Compared to H-DVA working in zero field state, the acceleration magnitude of pipeline vibration was furtherly reduced by 8.8% when applying -1.5A to H-DVA under 55Hz excitation. Similarly, the acceleration magnitude was furtherly reduced by 22.2% when applying 2A to H-DVA under 85Hz excitation. Thus, these findings confirmed that the H-DVA proposed in this paper not only achieved the bi-directional magnetic tunability, but also improved the vibration absorption effect for pipeline vibration.

Improving the performance of magnetorheological elastomer-based adaptive isolator through integrated compression-torsion structure

“…MRE is created by dispersing micro-sized magnetic particles into a polymer elastomer matrix, rendering it a smart material with rapidly and reversibly controlled properties under the influence of an applied magnetic field [10][11][12]. Based on this advantage, MRE has found extensive applications in the development of various vibration isolation and absorption devices, aimed at mitigating the impact of harmful external vibrations on engineering structures [13][14][15].…”