Frequency and damping adaptation of a TMD with controlled MR damper

Abstract

This paper describes the new concept of a semi-active tuned mass damper with magnetorheological damper (MR-STMD). The real-time controlled MR damper force emulates controlled damping and a superimposed controllable stiffness force to augment or diminish the force of the passive spring stiffness which enables us to control the MR-STMD natural frequency. Both the damping and natural frequency are tuned according to Den Hartog’s formulae to the actual dominant frequency of the main structure irrespective of whether it is a resonance or a forced frequency. The MR-STMD is experimentally validated on the Empa bridge with a 15.6 m main span for different added masses to shift its resonance frequency −12.2% and +10.4% away from its nominal value. The experimental results are compared to those obtained when the MR-STMD is operated as a passive TMD that is precisely tuned to the nominal bridge. The comparison shows that the MR-STMD outperforms the TMD both in the tuned and all de-tuned cases by up to 63%. Simulations of the MR-STMD concept point out that the proposed semi-active control algorithm is most suitable for MR-STMDs due to the small amount of clipped active forces. A sensitivity analysis demonstrates that the real MR-STMD could be even more powerful if the force tracking errors in the MR damper force due to the current driver and MR fluid dynamics and remanent magnetization effects could be further reduced. The MR-STMD under consideration represents the prototype of the 12 MR-STMDs that have been running on the Volgograd Bridge since late fall 2011.

Semi-Active Control Systems in Bridge Engineering: A Review of the Current State of Practice

“…Moving towards real applications, a semi-active TMD with a magneto-rheological damper (MR-STMD) ( Figure 6) was installed as a retrofit measure on the Volgograd Bridge (Russia) after it exhibited large wind-induced vibrations 70,71 . The main feature of the MR-STMD concept is that the real-time controlled MR damper (used instead of passive dampers in common TMDs) emulates a controllable stiffness force that modifies the stiffness of the passive springs and thereby tunes the MR-STMD frequency to the actual frequency of the bridge, and a controllable friction force that generates frequency-dependent energy dissipation.…”

Vibration Control Design for a Plate Structure with Electrorheological ATVA Using Interval Type-2 Fuzzy System

“…Due to the controllable and varied physical properties of smart materials, they are also used for living infrastructures, mechanical structures, and seismic vibration controls for decades . Smart materials and structures that possess electromechanical characteristics have been widely used for active vibration control or semi-active vibration control, such as piezoelectric damper [4][5][6][7][8], eddy current damper [9], magnetostrictive spring [10], magneto-rheological fluid (MRF) damper [11][12][13], electro-rheological fluid (ERF) damper [14][15][16][17], shape memory alloy (SMA) [18][19][20][21], and electromagnetic and piezoelectric shunt damper [22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Smart materials have one or more properties changed by the external stimuli, such as temperature, stress, electric field or magnetic field.…”

Vibration Control Design for a Plate Structure with Electrorheological ATVA Using Interval Type-2 Fuzzy System

“…Due to the controllable and varied physical properties of smart materials, they are also used for living infrastructures and mechanical structures, and seismic vibration controls for decades . Smart materials and structures that possess electromechanical characteristics have been widely used for active vibration control or semi-active vibration control, such as piezoelectric damper [4][5][6][7][8], eddy current damper [9], magnetostrictive spring [10], magneto-rheological fluid (MRF) damper [11][12][13], electro-rheological fluid (ERF) damper [14][15][16][17], shape memory alloy (SMA) [18][19][20][21], electromagnetic and piezo-electrical shunt damper [22][23][24][25][26][27][28][29][30][31][32][33][34][35]. Smart materials have one or more properties changed by the external stimuli, such as temperature, stress, electric or magnetic fields.…”