Ultrasonic TOFD Testing Model for Crack Measurement in Thick Wall Weldment
In this paper, both forward and inverse problem about crack testing by using ultrasonic Time of Flight Diffraction (TOFD) B-scan mode are studied. For forward problem, the propagation behavior of ultrasonic beam is described, and the electrical and electromechanical elements of inspective system are characterized by system efficiency factor.Based on this, crack simulating model is established by employing Kirchhoff approximation theory. By using the model, ultrasonic TOFD A-scan line is simulated and B-scan foreground image is synthesized. For inverse problem, in order to obtain lateral location and buried depth information of crack in the weld, B-scan image reconstruction is studied. According to the dynamic relation between the probes and crack tip in the course of testing, synthetic aperture focusing (SAF) algorithm for image enhancement is developed. The results show that the simulated dada are in better accordance with the measured ones and the presented SAF algorithm can be validated by the simulating model. Processed by SAF, high resolution image can be obtained by using transducers with poor sound directivity and lower frequency, and measurement can be carried out rapidly with high accuracy.
Model Ultrasonic TOFD SAF Weld crack
Tie GANG Dazhao CHI
State Key Laboratory of Advanced Welding Production Technology,Harbin Institute of Technology, Harbin, 150001 China
国际会议
第十七届世界无损检测会议(17th World Conference on Nondestructive Testing)
上海
英文
775-780
2008-10-25（万方平台首次上网日期，不代表论文的发表时间）