engleski

Electromechanical Properties of a Non- Destructive Evaluation Ultrasound Transducer at Different Electrical Excitation Levels

The electrical excitation level dependence of electromechanical behavior of a non-destructive evaluation ultrasound transducer has been investigated. Notable differences between the transducer input electrical impedance and acoustic properties at low excitation voltages (~1V), most often used in electromechanical characterizations by performing frequency sweeps, and at high excitation voltages (~250V), generally used to drive ultrasound transducers in non-destructive evaluation applications, have been emphasized. For the purpose of this work, a circular ultrasound transducer of center frequency 2MHz was constructed by using a PZT piezoelectric disk, epoxy-based acoustically passive front matching and backing layers, an electrical impedance matching element, housing and coaxial cable. The transducer was characterized around the thickness extensional vibration mode both by using low and high voltage electrical excitation signals. The characterization of the electromechanical properties was conducted at several different stages of the transducer construction and for several excitation signal waveforms and levels. The influence of high electrical excitation levels on significant changes in transducer electromechanical properties has been discussed within the KLM (Krimholtz, Leedom, and Matthaei) and Rayleigh theoretical models.

ultrasound NDE transreciever; electromechanical parameters; impulse and sweeping excitation

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