Receiving principles and experimental test of several commonly used methods for laser ultrasonic thickness measurement

Laser ultrasonic technology has become an effective method and technological means for thickness measurement of metal materials nowadays. Generally, common method for receiving laser ultrasonic signals has piezo-electric transducer (PZT), laser interferometer and electro-magnetic acoustic transducer (EMAT). In this paper, the receiving principles of three kinds of receiving methods are given, and the diagrams of three methods with different thickness obtained by experiments are drawn. Each method has its own advantages and disadvantages, so appropriate receiving method should be selected according to actual needs for engineering application.