Location

La Jolla, CA

Start Date

1-1-1998 12:00 AM

Description

A general model of an ultrasonic flaw measurement system can be developed using the fundamental reciprocity formulation of Auld [1]. This general model can be reduced to a more explicit form by assuming that the waves incident on the flaw are quasi-plane waves, resulting in the Thompson-Gray measurement model [2]. In the Thompson-Gray model, the frequency components of received voltage, V0(ω), in a pitch-catch immersion setup can be written in a product fashion as V0(ω)=β(ω)P(ω)M(ω)T1(ω)C1(ω)A(ω)T2(ω)C2(ω) where P(ω) accounts for the time delay in going from the transmitting transducer to the receiving transducer, M(ω) is due to the material attenuation, T 1(ω) and T 2((ω) are transmission terms that characterize the amplitude changes when going through the fluid- solid interfaces on transmission and reception, respectively, C 1(ω) and C 2(ω) are diffraction correction terms that account for the finite beam characteristics of the transducers on transmission and reception, and A(ω) is the far field scattering amplitude of the flaw. The term β(ω) is an “efficiency factor” that is a function of the electrical properties of the pulser/receiver, the associated cabling, and the ultrasonic transducers. Thus, β(ω) accounts for all the electrical to mechanical and mechanical to electrical conversion processes that contribute to the entire measurement process.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

17A

Chapter

Chapter 4: NDE Sensors and Fields

Section

UT Sensors, Transducers and Fields

Pages

891-898

DOI

10.1007/978-1-4615-5339-7_115

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Electromechanical Modeling of Ultrasonic Transducers

La Jolla, CA

A general model of an ultrasonic flaw measurement system can be developed using the fundamental reciprocity formulation of Auld [1]. This general model can be reduced to a more explicit form by assuming that the waves incident on the flaw are quasi-plane waves, resulting in the Thompson-Gray measurement model [2]. In the Thompson-Gray model, the frequency components of received voltage, V0(ω), in a pitch-catch immersion setup can be written in a product fashion as V0(ω)=β(ω)P(ω)M(ω)T1(ω)C1(ω)A(ω)T2(ω)C2(ω) where P(ω) accounts for the time delay in going from the transmitting transducer to the receiving transducer, M(ω) is due to the material attenuation, T 1(ω) and T 2((ω) are transmission terms that characterize the amplitude changes when going through the fluid- solid interfaces on transmission and reception, respectively, C 1(ω) and C 2(ω) are diffraction correction terms that account for the finite beam characteristics of the transducers on transmission and reception, and A(ω) is the far field scattering amplitude of the flaw. The term β(ω) is an “efficiency factor” that is a function of the electrical properties of the pulser/receiver, the associated cabling, and the ultrasonic transducers. Thus, β(ω) accounts for all the electrical to mechanical and mechanical to electrical conversion processes that contribute to the entire measurement process.