Location

Snowmass Village, CO

Start Date

1-1-1995 12:00 AM

Description

Polymethyl methacrylate (PMMA) is a kind of typical amorphous polymer, whose main mechanical property is viscoelasticity that can be of great importance in materials characterization and nondestructive evaluation (NDE). On the other hand, ultrasonic NDE technique is one of the basic methods to characterize polymeric materials. By the measurements of the velocity and attenuation of the bulk waves as a function of frequency and temperature [1–3], the moduli of PMMA can be deduced and various relaxation phenomena can be investigated. However, as we know, the studies on the SAW attenuation of PMMA have not been reported. It is difficult for the contact ultrasonic method to do so because the effect of the electric transducers working in the contact way on the SAW field can not be avoided. Some disadvantages of using electronic ultrasonic method to characterize polymers, such as the measurement must be made in the immersion apparatus and the piezoelectric transducers with different frequencies must be used to obtain the attenuation spectra etc. have been overcome by the means of the laser ultrasonic technique [4,5]. The noncontact nature of the laser ultrasonic technique can also eliminate the effect of the contact measurement on the SAW field and make it convenient for the measurement at elevated temperatures. Therefore the laser ultrasonic technique is extremely suitable for the study on the attenuation of SAW.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

14A

Chapter

Chapter 2: Emerging Inspection Technologies

Section

Laser Based Ultrasonics

Pages

577-583

DOI

10.1007/978-1-4615-1987-4_70

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Study on Saw Attenuation of PMMA Using Laser Ultrasonic Technique

Snowmass Village, CO

Polymethyl methacrylate (PMMA) is a kind of typical amorphous polymer, whose main mechanical property is viscoelasticity that can be of great importance in materials characterization and nondestructive evaluation (NDE). On the other hand, ultrasonic NDE technique is one of the basic methods to characterize polymeric materials. By the measurements of the velocity and attenuation of the bulk waves as a function of frequency and temperature [1–3], the moduli of PMMA can be deduced and various relaxation phenomena can be investigated. However, as we know, the studies on the SAW attenuation of PMMA have not been reported. It is difficult for the contact ultrasonic method to do so because the effect of the electric transducers working in the contact way on the SAW field can not be avoided. Some disadvantages of using electronic ultrasonic method to characterize polymers, such as the measurement must be made in the immersion apparatus and the piezoelectric transducers with different frequencies must be used to obtain the attenuation spectra etc. have been overcome by the means of the laser ultrasonic technique [4,5]. The noncontact nature of the laser ultrasonic technique can also eliminate the effect of the contact measurement on the SAW field and make it convenient for the measurement at elevated temperatures. Therefore the laser ultrasonic technique is extremely suitable for the study on the attenuation of SAW.