Location

Brunswick, ME

Start Date

1-1-1997 12:00 AM

Description

Most of the large variety of non-destructive methods and their associated measurement instruments for flow, multilayer and crack detection are based on two physical principles: eddy-current monitoring and ultrasonic pulse- echo measurement. Application of the first one is limited by low spatial resolution and is useful for the study of magnetic metal samples. A well developed ultrasonic pulse-echo detection technique is free of such limitations, and can be used for quality control and material testing. Almost all commercially available ultrasonic NDT devices work at ultrasonic frequencies of 0.1 to 20 MHz and thus have spatial resolutions worse than 0.3–0.5 mm. Only simple evaluations of pulse-echo characteristics are usually made, such as determinations of transit time and maximum echo amplitude. As a result, ultrasonic inspection is used only to determine whether or not a test piece is free of discontinuities, and for thickness measurements.

Book Title

Review of Progress in Quantitative Nondestructive Evaluation

Volume

16B

Chapter

Chapter 7: New Inspection Procedures

Section

New Techniques

Pages

1845-1851

DOI

10.1007/978-1-4615-5947-4_241

Language

en

File Format

application/pdf

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Jan 1st, 12:00 AM

Imaging of Deep Internal Layers in Layered Polymer Systems Using the Ultra-Short Pulse Acoustic Microscope

Brunswick, ME

Most of the large variety of non-destructive methods and their associated measurement instruments for flow, multilayer and crack detection are based on two physical principles: eddy-current monitoring and ultrasonic pulse- echo measurement. Application of the first one is limited by low spatial resolution and is useful for the study of magnetic metal samples. A well developed ultrasonic pulse-echo detection technique is free of such limitations, and can be used for quality control and material testing. Almost all commercially available ultrasonic NDT devices work at ultrasonic frequencies of 0.1 to 20 MHz and thus have spatial resolutions worse than 0.3–0.5 mm. Only simple evaluations of pulse-echo characteristics are usually made, such as determinations of transit time and maximum echo amplitude. As a result, ultrasonic inspection is used only to determine whether or not a test piece is free of discontinuities, and for thickness measurements.