Promptness and dissipative capacity of MR dampers: Experimental investigations

Abstract

The experimental analyses of response time and dissipative capability of two prototype magnetorheological semi-active dampers are presented herein. These activities have been conducted during an Italian research project on devices manufactured in Germany. A detailed report of the response time analysis based on experimental data is presented and commented. It is shown how the control delays are strongly dependent on the effectiveness of the electric part of the control hardware, generally being less than 10 ms if special care is paid in designing the whole control chain. The dissipative capacity of the devices is further analyzed under the action of different imposed displacement laws, investigating a large range of displacement amplitudes, frequencies, and feeding currents. Interesting comparisons in terms of energy are finally drawn between magnetorheological damper used in a passive (constant current) and in a semi-active mode (variable current commanded by an energy-based control logic)

Experimental Assessment of a Skyhook Semiactive Strategy for Seismic Vibration Control of a Steel Structure

“…of the University of Napoli Federico II, in order to evaluate the characteristics of their operations [13,15]. They look pretty much like conventional fluid viscous damper, with the exception of some extra wiring needed to feed the coils inside the body.…”

“…The magnetic field produced in the device is generated by a magnetic circuit, and the current in the circuit, provided by a power supply commanded by a voltage input signal, is in the range = 0 ÷ 3 A. Figure 3 shows the results of four "passive" tests performed during the experimental campaign described in [13,15], carried out at the same displacement frequency (1. and 2.7 A). It shows how much the response behavior is variable according to the feeding current.…”

Response Time of MR Dampers for Seismic Semiactive Control: Experimental Measures and Possible Prediction

“…During these tests, the power supply has been used according to a current-driven scheme. All these tests have been also analyzed from a dissipated energy point of view in [11]. …”

A Smart Base Restraint for Wind Turbines to Mitigate Undesired Effects Due to Structural Vibrations

“…The high promptness of response of the SA control chain based on the use of MR dampers and of an appropriate electronic and power equipment has been experimentally demonstrated [8], showing that unavoidable delays however are always less than 10 ms, thus negligible compared to the long period of the flexible structures under examination. This is one of the aspects strongly encourage the use of such technology for the application in question.…”