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With the aim of improving micro-vibration isolation, a hybrid magnetorheological elastomerfluid (MRE-F) mount with variable stiffness and damping is presented. The proposed mechanism combines a magnetorheological elastomer stiffness unit with a magnetorheological fluid damping unit in a parallel connection. On the basis of a structural design and magnetic circuit analysis, the performance of this prototype was investigated experimentally using an MTS machine under multi-operating conditions. The field-controlled capacities, including resultant stiffness, equivalent damping, as well as the amplitude and frequency dependence were validated based on the experimental data. This work demonstrates the feasibility of applying this hybrid MRE-F mount to isolation systems with a small displacement.

In this article, an adaptive magnetorheological elastomer bearing prototype for seismic mitigation of bridge superstructures is designed and manufactured. The magnetorheological elastomer bearing is developed featuring conventional laminated structure in the seismic rubber bearing. Besides, the magnetic circuit design of the laminated magnetorheological elastomer bearing is verified by electromagnetic analysis, and a base-isolated testing system is established to obtain the acceleration transmissibility under various applied currents. The experimental results indicate that the resonance frequency of the integrated system can be tuned from 10 to 20 Hz, and the transmissibility peak value reduces 20.67% simultaneously, for which the proposed bearing can be used for seismic mitigation. Finally, the stiffness and damping of the laminated magnetorheological elastomer bearing integrated vibration mitigation system are identified by the response characteristics.

Abstract. A new dipping basalt fiber reinforced concrete (DBF-RC) was developed in this study. The surface of fiber was modified by dipping into epoxy resin. The mix of DBF was first researched on cement mortar, and then on concrete. The workability and mechanical properties of cementitious materials were investigated. Experimental results show that the optimum proportion of DBF is 1%, and with this mix, the compressive strength, flexural strength and flexural toughness of concrete can be improved effectively.