Performance evaluation of a novel squeeze mode magnetorheological fluid damper with pre-compression mechanism under small amplitude and medium-high frequency

Under small amplitude and medium-high frequency excitations, mechanical properties of squeeze mode magnetorheological (MR) damper change obviously which are different from general properties. Performance will be attenuated seriously which is known as the high frequency hardening effect. In this paper, mechanical performance of a novel squeeze mode MR damper with pre-compression mechanism under such excitations has been analyzed qualitatively and quantitatively. A novel squeeze mode MR damper with pre-compression mechanism is proposed to improve performance. Then, considering viscoelasticity, inertial effect and pre-compression, an optimized model has been proposed which can precisely describe the performance under such excitations. Comparing with experimental results, performances of squeeze mode MR damper under such excitations are quite different from general properties. The damping force decreases gradually without a sudden decrease at the maximum stroke and it shows stiffness characteristics obviously. What's more, the maximum damping force is up to 1916 N with an increase of 321.6% at the current of 1 A and frequency of 10 Hz. The energy dissipation is increased by 342% with pre-compression of 1 MPa. The damping force and energy dissipation increase rapidly with increasing the pre-compression. Experimental results demonstrate that the high frequency hardening effect is effectively improved by pre-compression.