A U.S. Navy research program is using lasers to predict damage in mechanical parts. The result could be a system of lasers built into military equipment that continuously monitors for parts fatigue, warning users before dangerous failures happen.
Researchers at the U.S. Navy's Naval Research Laboratory (NRL) have proven their ability to detect acoustic emissions from cracks in riveted lap joints. The laser-based monitoring system can monitor "key structural parameters such as temperature, strain, impacts, and cracks". The program involves installing "distributed feedback fiber laser acoustic emission sensors" into a series of riveted lap joints. Each sensor is about the size of a human hair, and is inserted into a groove in the lap joint. The lap joints were then put into a two-hour accelerated fatigue test.