Semi-active stabilisation of a pipe conveying fluid using eddy-current dampers: state-feedback control design, experimental validation

Abstract

An application of electromagnetic devices of the motional type (i.e. eddy-current dampers) to improve the dynamic stability of a cantilever pipe discharging fluid is proposed. When the flow velocity reaches a critical value, this system loses stability through the flutter. A contactless damping device is used. This actuator is made of a conducting plate attached to the pipe that moves together with it within the perpendicular magnetic field that is generated by the controlled electromagnets. During the motion the eddy currents in the plate and a resultant drag force of a viscous character are generated. First, an optimal control problem that aims to stabilise the system with the optimal rate of decrease of the system's energy is posed and solved. Then a state-feedback parametrization of the obtained optimal control, which can be used in a closed-loop scheme is proposed. The effectiveness of the designed optimal controller is validated by making a comparison with the corresponding passive solutions on the specially designed and constructed experimental test stand of a pipe conveying air.

Stabilization of a cantilever pipe conveying fluid using electromagnetic actuators of the transformer type

“…What sets them apart is the incorporation of internal damping in the pipe and the effect of the actuators -their mass and electromagnetic force acting on the pipe. This equation is also similar to the equation used by the authors in the research on dynamics and control of the pipe with motional actuators [36]. The only difference is that instead of the term expressing the electromagnetic viscous drag, the right hand side of the equation contains the expression for the electromagnetic force FðtÞ…”

“…Such devices have found numerous applications, for example in vehicle suspension systems [10], beam structures [45] or elevators and other rail systems where they act as electromagnetic brakes [26]. In our previous works we analyzed the effect of electromagnetic devices of the motional type to stabilize a fluid-conveying pipe which proved to be efficient when used both in passive way as well as in a closed-loop feedback control, depending on the state of the system [30,36].…”

Dynamics of axially functionally graded pipes conveying fluid using a higher order shear deformation theory

“…The total kinetic energy comprising those of pipe motion and fluid flow can be written in the form pf K K K =+ (9) where Kp and Kf are kinetic energies of pipe and fluid, respectively and can be expresses as Note that, in the present study, a typical material property of the pipe, denoted by Z, including E, ν, μ, and ρ, is assumed to be axially varying from upstream, 1 0…”

“…Abdollahi, Dehghani Firouz-abadi [8] focused on stability and flexural vibration analyses of rotating pipes undergoing simultaneous external and internal fluid loadings. In some studies, using damping devices such as eddy-current dampers, the effort have been made to stabilize FCPs when the flow velocity inside them reaches the critical value [9].…”

Experimental Study on an Inerter Eddy Current Damper for Base-Isolated Structure

“…The eddy current effect is generated by the relative motion between a nonmagnetic conductive material and a magnetic field [1][2][3][4][5] or by the time-varying intensity of a stationary magnetic field [6][7][8] . The benefits of eddy current effect that is used in a damping device include no mechanical contact friction, stability at high temperatures, and simple form, which has led to its broad implementation in the industry [9][10][11][12][13][14][15][16] .…”