Project TCE

Transducer Characterization - beam pattern and resolution

Introduction

Ultrasonic transducers are electro-mechanical devices that generate vibrations when excited with an electric pulse.

The mechanical part of the transducer can be modeled using a suitable field generation model, the simplest is the piston model. The model approximates sound field measured for a real transducer. The sound field takes the form of main lobe and side lobes with geometry depending on the transducer geometry, frequency and medium parameters (see figures below).

Frequency response of the electrical part is characterized by resonances occuring at frequencies corresponding to different vibration modes of the piezoelement used in the transducer and their multiples.

Beam pattern of an immersion transducer	Acoustic field emitted by an immersion transducer

Goal

To measure and characterize acoustical properties of two immersion transducers:

- unfocused transducer from PANAMETRICS

- focused transducer from PANAMETRICS

Instrumentation

PC based ultrasonic scanner system, transducers from PANAMETRICS

Procedure

• Literature study
• Training on ultrasonic scanner
• Measurement of beam patterns for point reflectors in water
• Measurements of responses to wire reflectors in water
• Reporting

 

Extra task

To simulate acoustic field of one of your transducers using software tool DREAM

Requirements

1. Full report including: theoretical part, experiment description, results of the conducted measurements and conclusions.
2. Oral presentation of the experiment
3. Basic knowledge of the ultrasonic techniques

References

Nondestructive Evaluation of Materials, Compendium for 4MV, 1999, Sec 3 & 4

Ultrasonic NDT from Krautkrämer

Transducers - NDT resource Center