Laser Interferometry-Based Health Monitoring Technology for Plate Structures

Conventional piezoelectric sensors used for health monitoring of plate structures are affected by their contact measurement method and narrow bandwidth, thus reducing the accuracy of the monitoring process, while the system design of external differential interferometry is complex and costly, therefore a laser vibration measurement method based on the zero-difference interference principle is investigated for health monitoring of plate structures. The principle of laser zero-difference interferometry method is analysed, the laser zero-difference interferometry system is designed, and finally the system is integrated and active lamb wave monitoring experiments of the plate structure are carried out. The experimental results reveal that the system can record signals with frequencies ranging from 200kHz to 400kHz and is of practical technical interest for usage in the field of structural health monitoring.