Laser Ultrasonics for the Evaluation of Composites and Coatings

摘要

Laser ultrasonics, an esoteric laboratory curiosity in the 1960s, is finding its niche in industry today. The technique has evolved concurrently with advances in electronics and optics to achieve recent breakthroughs Two applications will be presented here: rapid inspection of complex shaped composite structures and in-situ monitoring of a coating process in hostile environments. The ability to inspect complex shapes rapidly with in-process capability is a clear cost benefit for the NDT community, where nondestructive testing has long been viewed as an added cost. Complex shape composite structures are now common, particularly in the aircraft industry, and may be critically load bearing. The ability to inspect virtually any shape without immersion is becoming ever more important. The rapidly growing aircraft engine coating industry is moving toward higher temperature coatings and therefore more efficient engine operation. Control of the coating process will be cost effective and there simply is no other way to quantitatively assess the process at temperatures as high as 2,400℃ (2,552 ℉). These examples serve to demonstrate how a deep understanding of a complex subject has led to timely practical applications.