IMPROVEMENT IN CRACK DETECTION BY ULTRASONIC PULSE-ECHO WITH LOW FREQUENCY EXCITATION.
Abstract
A program of analytical and experimental research is being conducted to investigate the effect of stress fields on the ultrasonic energy reflected from thin flat cracks in solids. It has been established that the amplitude of ultrasonic signals reflected from a crack interface is decreased significantly when a compressive stress field is applied to the region of the crack. Also, within certain limitations, the amplitude is increased with increasing tensile stress. Thus, a crack in compression is more difficult to detect by pulse-echo than an unstressed crack, and the capability of detecting the crack is improved by application of tensile stress. Technically, it is possible to induce the stress required for improved detection by introducing low frequency sound excitation in the region of the crack. Efforts are being continued to further develop and to optimize this technique. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1970
- Accession Number
- AD0708747
Entities
People
- John G. Sessler
Organizations
- SRC Inc.