STUDY OF SOME FEATURES OF THE LASER OPTICAL-ACOUSTIC METHOD FOR TECHNICAL DIAGNOSTICS OF HEAT AND POWER ENGINEERING OBJECTS

Abstract

The article presents the diagnosis of heat power facilities. The distinguishing features of the applied method are shown in solving a number of technologically important diagnostic problems, in particular: quality control of pipe welds, determination of residual stress, structural, mechanical, elastic properties of materials. The physical foundations of the laser optoacoustic method for exciting ultrasonic waves are theoretically investigated. It is shown that this method is based on laser thermooptical excitation of broadband ultrasonic signals in a test object. Absorbed in a thin surface layer of the object under study, the laser pulse excites a broadband ultrasonic pulse. Propagating in an object, an excited ultrasonic pulse (either a transmitted or scattered ultrasonic signal with a high temporal resolution is recorded) carries information about the object under study.