From Ultrasonic and Advanced Methods for Nondestructive Testing and Material Characterization


Lester W. Schmerr Jr.

Center for Nondestructive Evaluation and the Dept. of Aerospace Engineering Iowa State University Ames, Iowa 50011

It will be shown that it is possible to completely characterize an ultrasonic nondestructive flaw measurement system and simulate the measured flaw signals. This characterization includes the pulser/receiver, cabling, and transducers present as well as the propagating and scattered acoustic/elastic wave fields. All the elements of this comprehensive ultrasonic measurement model will be discussed as well as practical methods for obtaining those elements through a combination of models and measurements.

1. Introduction

Ultrasound is widely used for both medical evaluations and industrial inspections. In medical applications the ultrasound is typically propagating in tissue and the interactions of the sound with objects such as tumors are normally displayed in the form of ultrasonic images for evaluation by a physician. In industrial nondestructive evaluation (NDE) ultrasonic tests the ultrasonic waves are traveling in structural materials or components and the focus is often on evaluating those components for flaws such as cracks. While the results of the interaction of the sound with flaws can also be displayed as an ultrasonic image, a more common type of display used in industrial inspections is a received voltage versus time trace, ? R ( t), on an oscilloscope, called an A-scan, as shown in Fig. 1 for a typical immersion ultrasonic NDE flaw inspection system. Since images are generated by processing combinations of such A-scans, A-scan data provides the fundamental basis...

Products & Services
Flaw Detectors
Flaw detectors are used to detect or measure defects in raw materials or finished products. This product area includes fault detectors, NDT instruments that are used to find faults in electrical, mechanical, optical, or other systems.
Ultrasonic Instruments
Ultrasonic instruments use beams of high frequency, short wave signals to inspect, monitor, and measure materials and components.
Web Inspection Systems
Web inspection systems are used for the detection and/or automatic identification of web or web coating patterns and defects or problems such as streaks and blurs.
Pulser-receivers generate ultrasonic pulses, which are propagated into materials for NDT testing.

Topics of Interest

Overview Cheng-Kuei Jen and Makiko Kobayashi Industrial Materials Institute, National Research Council Canada 75 de Mortagne Blvd., Boucherville, QC, J4B 6Y4, Canada

Of all the applications of industrial ultrasonic testing, flaw detection is the oldest and the most common. Since the 1940s, the laws of physics that govern the propagation of sound waves through...

10.1 INTRODUCTION This chapter deals with the use of piezoelectric wafer active sensors (PWAS) to detect structural damage using wave propagation techniques. This application of PWAS technology...

The high-frequency sound waves used for flaw detection and thickness gaging in ultrasonic nondestructive testing applications are generated and received by small probes called ultrasonic transducers.

Chapter List Chapter 21: Computational Intelligence Methodologies for Non Destructive Testing/Evaluation Applications Chapter 22: Split Spectrum Processing and Automatic Flaw Detection Chapter 23:...