Electronic Signal Processing Techniques. Phase 2. Nondestructive Testing
Annual rept. 30 Oct 1969-29 Oct 1970
BOEING AEROSPACE CO SEATTLE WA
Pagination or Media Count:
Signal averaging was used to enhance flaw indications in the ultrasonic inspection of electron beams welds. An electronic gate, synchronized to the transducer motion through the use of an electrically controllable delay was also used to enhance flaw indications. To aid in electrical signal processing, a technique for recording ultrasonic video information on a low- frequency tape recorder was developed. In preparation for optical matched filtering, ultrasonic information was recorded on a photographic transparency in a C-scan format. An XY scanning densitometer was constructed to remove the intensity modulated information from the film and to aid in the production of hard copy recordings. Phaselock detection was used to perform through transmission eddy current testing. Methods were developed for obtaining quantitative through transmission data. Through transmission thickness measurements were performed and procedures were developed for obtaining a linear relationship between part thickness and eddy current signal. Applications to chemical milling and in-motion thickness measurements were demonstrated. Phaselock detection and signal averaging were used to measure resistance and inductance changes in conventional eddy current coils during a scanning operation. Quantitative data was produced from bridge unbalance signals.
- Test Facilities, Equipment and Methods