State-Switched Absorber for Semi-Active Structural Control

Abstract

A system that has the capability to make instantaneous changes in its mass, stiffness, or damping may be termed a state-switchable dynamical system. Such a system will display different dynamical responses dependent upon its current state. For example, state-switchable stiffness may be practically obtained through the control of the termination impedance of piezoelectric stiffness elements. If such a switchable stiffness element is incorporated as part of the spring element of a vibration absorber, the change in stiffness causes a change in the resonance frequencies of the system, thereby instantaneously "retuning" the state-switched absorber to a new frequency. This paper briefly develops the fundamental analysis tools for a Single-Degree-of-Freedom state-switchable device, and then considers the application of such a device for the purpose of vibration control in a 2-DOF system. Simulation results indicate that state-switched vibration absorbers may be advantageous over classical passive tuned vibration absorbers under certain conditions.

Application of dynamic vibration absorbers in structural vibration control under multi-frequency harmonic excitations

“…Similar to the work [20], the performances of a single DVA, SSA and dual DVAs optimized for the identical set of exciting frequencies x 1 and x 2 are compared.…”

“…Following the work of Cunefare et al [20], the dynamical systems described above may all be cast in terms of a state-space representation as…”

“…For a two-state SSA, the switching control law developed by Cunefare et al is used to adjust its stiffness [20]. The switching principle is…”

“…Cunefare et al developed a kind of state-switched absorber (SSA) which is a single-degree-of-freedom oscillator, but one with a spring whose stiffness can assume a number of discrete values [20]. It can address the control of multifrequency excitation.…”

Switched Stiffness Vibration Controllers for Fluidic Flexible Matrix Composites

“…The performance of this controller under the step load inputs, however, is not discussed. Cunefare et al [22] propose a substitute for state-switching that avoids instantaneous changes in potential energy by switching at zero strain. Fluidic Flexible Matrix Composites (F 2 MC) are variable stiffness structures consisting of Flexible Matrix Composite (FMC) tubes with two families of bers wound at α with respect to the longitudinal axis (See Fig.…”