Laser Phase Array Generation of Ultrasound for On-Line Weld Quality Control

点击翻译按钮获取中文摘要

The purpose of this research is to develop a novel, efficient technique of noncontacting laser phased array generation of ultrasound, for the nondestructive evaluation (NDE) of solids and processes. The new technique uses an array of laser beams in place of a single beam. The research will include a basic study to evaluate the performance of and develop an analytical model for the phased array. Specific applications to noncontact NDE on-line control of the depth of penetration and porosity during a gas metal arc welding (GMAW) process will be pursued. An electromagnetic acoustic transducer will be used as a noncontact receiver. The research has five phases as follows: (1) development of an analytical model for predicting the generation of ultrasound by a laser phased array; (2) experimental verification of the model for the phased array; (3) application of phased array to noncontact NDE on-line control of the depth of weld pool penetration and porosity; (4) development of an analytical model for propagation of sound through the weld pool; and (5) development of the data acquisition system and algorithms. The information on weld pool penetration and porosity extracted from the ultrasonic signal will be used in the system feedback for the welding power-supply, current, or speed control, to achieve the desired penetration and porosity.