关键词: 不均匀温度场, 定位精度, 多物理场耦合, 位置修正

Abstract: Researching the propagation characteristics of ultrasonic wave in solid with high temperature and non-uniform temperature gradient is exceedingly essential. According to the relationship between temperature gradient and stress gradient, it builds two dimensional finite element model of the ultrasonic wave propagate in mild steel. The disciplinarian between temperature field and positioning accuracy of defects is analyzed. And available experimental data has been used to confirm the correctness of a part of simulation results. The results show that defect positioning error increases due to the following reasons: the rising in temperature; the increasing of temperature difference in?between the two sides of the solid; the increasing of distance defects from the detector. Empirical equation to compensate positioning ultrasonic nondestructive testing is established which can improve the positioning accuracy of defects. Those empirical equations can play a guiding role in engineering.

Key words: high-temperature, non-uniform temperature gradient, positioning accuracy, multi-physics coupling, positioning correction