Abstract
Piezoelectric film is a flexible, thin and lightweight sensor/actuator material. Conventionally, it has been used for the development of the thin and lightweight sound insulation control device based on the vibration control of plate or beam with piezoelectric film actuators and sensors. In most studies which has treated the relationship between the placement of piezoelectric films and control effects, metal materials (such as aluminum) of thickness ranging from 1mm to 5mm was considered as the controlled plate structures. However, there were few studies which treated the vibration analysis of much more thin plate materials with high flexibility such as resin materials of thickness under lmm. In general, vibration control effects of the flexible plate strongly depend on the placement of piezoelectric films. Especially, these dependencies tend to appear in case of fixed supported plate. Instead, depending on the placement of the piezoelectric film actuators, in the worst case, unwanted vibration modes of the plate are excited by these piezoelectric film actuators and the transmission noise will be augmented. In this study, at first, analytical models of rectangular plates with piezoelectric films are defined, and fundamental equations are derived. Then, the optimum placement of piezoelectric film actuators are investigated by forced vibration analysis of the plate. Here, since the application to sound insulation control is considered, frequency responses of the plate are evaluated in terms of volume velocity. After that, the behavior of the system is investigated analytically for the thinner plate with piezoelectric films in the optimum placements, and the results are discussed toward the development of the thinner and lighter sound insulation devices.
