Scientific studies dealing with mechanical vibration attenuation by means of piezoelectric actuators are mostly focused on special details of structure modeling through finite elements and the amount of attenuation that can be achieved. However, a little explored issue in the scientific literature is the size of the actuator in relation to the size of the vibrating structure and the voltage applied to the piezoelectric actuator in order to achieve optimum vibration attenuation. This paper presents a theoretical and experimental study of mechanical vibration control of an aluminum plate with attached piezoelectric actuator. The aluminum plate was clamped at all four sides and a piezoelectric actuator based on lead zirconium titanate (PZT) was positioned at its center. Its natural frequency was close to 50 Hz, which is a frequency being constantly present on oil drilling platforms, producing annoying sound. The contribution of this paper is the determination of the relationship between the areas of the aluminum plate and the PZT actuator associated with the voltage value applied to the piezo-actuator for the purpose of vibration attenuation. The work demonstrates the possibility of the development of open-loop control using finite elements, to attenuate the vibration via piezoelectric actuator plates. This method makes it possible to vary the electric voltage across the piezoelectric actuator and/ or the actuator dimensions involved, leading to the best attenuation condition. Numerical simulations and experimental results show the relation between size of the PZT actuator and the electric field which must be applied for best attenuation.