INFRARED IMAGING OF ULTRASONICALLY EXCITED SUBSURFACE DEFECTS IN MATERIALS

摘要

A thermal imaging system (10) for detecting cracks and defects in a component (12). An ultrasonic transducer (14) is coupled to the specimen (12) through a malleable coupler (16). Ultrasonic energy from the transducer (14) causes the defects to heat up, which is detected by a thermal camera (22). The ultrasonic energy is in the form of a pulse where the frequency of the ultrasonic signal is substantially constant within the pulse. A control unit (30) is employed to provide timing and control for the operation of the ultrasonic transducer (14) and the camera (22).