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Piezoelectric actuators are commonly considered for active vibration control of smart structures. The placement and sizing of the actuators are normally decided based on control effectiveness. A piezo actuator affects the host structure's mass and stiffness properties and thus alters the original system, which would have been designed to have a certain natural frequency spectrum in relation to the disturbance excitation. For a rotating structure, the mass of the actuator additionally contributes to the centrifugal stiffening effect. In the event of failure of the active system, natural frequencies of the structure with piezos (now rendered passive) become significant. Considering the example of a stationary and rotating beam-like structure, it is attempted to identify the piezo actuator sizing and location that possess significant control effectiveness yet cause minimal change in the system dynamics.

Placement and sizing of piezo actuators is normally based on control effectiveness. However, retrofitting of piezoelectric actuators alters the inherent stiffness/mass properties of the parent structure. In rotating structures, the additional mass due to piezo patches contributes to the centrifugal stiffening force. The parent structure is originally designed to have a certain natural frequency spectrum in relation to the disturbance excitation. In the event of failure of the active system, the dynamics of the structure with piezos (now rendered passive) will therefore become significant. Thus it will be helpful to determine locations for mounting piezo patches based on minimal natural frequency change yet with good control authority. In this study, a finite element based procedure for plate structures is presented. Favorable locations for mounting piezos based on minimal natural frequency changes are iteratively evolved from an initial configuration wherein the whole plate is covered with piezos. A modal controllability approach has been used for finding piezo mounting locations from a good controllability perspective. The procedure is demonstrated for simply supported square, swept-back, circular and rotating rectangular plates considering the first four modes.

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