Nondestructive Evaluation of Stress Using Ultrasound and Pulsed Heat
Abstract
Unique instrumentation was developed for high-precision time - resolved ultrasonic velocity measurement. Such instrumentation is not available commercially nor, as far as is known, has such a capability ever been developed previously. It has a significant potential for materials studies and possibly other areas as well, as for instance noninvasive biomedical applications. It was demonstrated that with such instrumentation, applied stress even of modest values can be detected at depths of at least 1 cm in aluminum. Furthermore, such detection was shown to be quantitative, i.e., the amplitude of the effect is proportional to stress magnitude, and its shape is responsive in the predicted manner to locality of the stress. In view of item 3, below, it is evident that this concept is a viable basis for nondestructive characterization of subsurface residual stress in metals. Methods for data inversion to obtain stress profiles from measured velocity were explored and it was found that two techniques give good results with simulated data and relatively large amounts of additive noise, namely: (a) generalized matrix inversion with constraints and (b) least mean squares parameter fitting. Keywords: Nondestructive evaluation; Ultrasonic sound; Pulsed heat; Acoustoelastic phenomenon; Metal stress.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1989
- Accession Number
- ADA205176
Entities
People
- Wallace L. Anderson
Organizations
- University of Houston