Engineering topics
Publications and source records attributed to Schaefer, Lloyd A..
Subtle indications of flaws extracted from ultrasonic waveforms. Ultrasonic-inspection system uses artificial intelligence to help in identification of hidden flaws in electron-beam-welded castings. System involves application of flaw-classification logic to analysis of ultrasonic waveforms.
Flaws identified faster than in ultrasonic inspection. Holographic technique detects hidden "unbonds", and does not require elaborate provisions for suppression of vibrations. Laser-shearographic apparatus used to observe object while stress being applied. Shearographic image indicative of deflection caused by stress. Also used to inspect complexly contoured surfaces.
Computed tomography (CT) enables identification of cracked thermistors without disassembly of equipment containing them. CT unit used to scan equipment and locate thermistors. Further scans made in various radial orientations perpendicular to plane of devices to find cracks. Cracks invisible in conventional x-radiographs seen.