Semi-active reduction of device casing vibration using a set of piezoelectric elements

Semi-active control methods are well known in context of structural vibration reduction. Despite of lower efficiency in comparison to the active methods, they are still the alternatives providing several advantages. The main benefit is that no additional energy is added to the system, which guarantees stability of the whole system. In addition, semi-active methods are more efficient than passive ones, especially for the systems controlled by e.g. switching or adaptive algorithms and with non-stationary excitation or unknown excitation during the design stage. The experiments have been performed using five Macro Fiber Composite piezoelectric elements attached to a thin, steel plate, which is a front wall of a cubical, rigid casing. The placement of the elements has been optimized based on the measured mode shapes of the structure. The vibration of other walls are reduced using the passive methods. This paper is focused on experimental evaluation of structural vibration reduction, depending on excitation and configuration of piezoelectric elements. Several types of electrical circuits are considered.