Research On Key Technologies Of Phased Array Laser Ultrasonic

With the development of modern industry, the demand for nondestructive testing is increasing. Based on traditional ultrasonic testing, some new kinds of ultrasonic testing technologies are coming, such as ultrasonic phased array technology and laser ultrasonic technology, this paper mainly focuses on the key technologies of phased array laser ultrasonic testing.Based on the basic theory of ultrasonic testing, the physical basis of ultrasonic flaw detection and physical quantities of ultrasonic field are described. Focus on the longitudinal wave sound filed irradiated by round transducer under ideal sound filed. Based on the longitudinal wave sound filed, study the ultrasonic sound pressure distribution, directivity and half angle of spread.In ultrasonic testing, ultrasonic transducers produce real acoustic field which is different from ideal sound field, and then analyze the reasons why it happens.Based on the understanding of sound field, use straight probe to produce ultrasonic and then use phased array probe to receive ultrasonic. Analyze the feasibility of experiments theoretically and then propose virtual focusing algorithm of ultrasonic imaging for this experiment, introduce imaging principle, ultrasound image reconstruction and ultrasonic signals' processing method. Based on this experiment use laser as ultrasonic source, propose a phased array laser ultrasonic detection method by phase control emission. Use ANSYS software to simulate the laser ultrasonic thermodynamic process, get the change of temperature on the surface of materials and displacement waveforms after laser irradiation. Use different ultrasonic probes to receive different kinds of ultrasonic waveforms after the simulation and use this system to test the defects on the surface of materials.Multiple arrays receiving, laser array design and ultrasonic imaging method are the key technologies of phased array laser ultrasonic. Based on the key technologies, design simulation multiple receiving detecting system and phase control emission laser ultrasonic detecting system. And use these detecting systems to test the defects in materials and on the surface of material, and also the virtual focusing algorithm is applied to these systems. These systems reflect the defects information visually, and the results are basically consistent compared with the actual defects. This project provides a foundation for further research on phased array laser ultrasonic.