Experiments and Analytical Modeling of Frequency-Targeted Laser Elastic Wave Generation and Detection in Aluminum Structures

Abstract

AbstractPropagating solid elastic waves forms the basis of multiple nondestructive evaluation (NDE) and structural health monitoring techniques. The majority require direct sensor contact with the material or structure being tested. Conventional NDE methods such as ultrasonic testing have rigorous coupling requirements and limited ranges for damage or defect detection. These requirements and limitations make inspection of large areas or complex geometries slow and cumbersome or altogether impractical. Removing the requirement for contact between the sensor and structure could greatly relax the geometric and size limitations of current elastic wave–based NDE techniques. Laser-based excitation and detection of solid elastic waves are demonstrated capabilities; however, existing laser-based excitation techniques lack the precision and flexibility required by NDE methods that target specific wave modes or frequencies. This proof-of-concept study investigates using a pulsing laser for frequency controlled exci...