PVDF large aperture spherical transducer in the transient mode

In this paper a converging impulsive beam interacting with a liquid-solid interface is studied both theoretically and experimentally. The model assumes that the transducer vibrates uniformly. The impulse response for the ultrasonic field received by the same transducer, after its reflection by a fluid/solid interface, has then been determined. This calculation has been carried out numerically, directly in the time-domain, by adding the Green's function contributions of each point of the transmitting surface. The main components of the predicted signals can be interpreted by a ray model. Experiments have been carried out with different solid specimens by using a PVDF spherical transducer excited by a very short electrical impulse. A good agreement between the theoretical and experimental signals is observed