超声波衍射时差法检测的有限元仿真

Ultrasonic time of flight diffraction detection by finite element simulation method

超声波检测是常用的无损检测方法,因超声波传播过程复杂,含有各种噪声信号,使缺陷衍射信号夹杂在大量噪声中难以被辨识出来,导致检测结果抽象.为了更好地应用超声波衍射时差法(TOFD)检测技术,对超声波衍射时差法的机理进行了有限元分析.首先,利用TOFD实验检测了带有人工缺陷的焊接钢板,提取了带有噪声的检测信号.其次,用ANSYS软件模拟仿真了超声波在工件中的传播过程,建立了焊接钢板和人工缺陷的有限元模型,分析确定了缺陷衍射信号.最后,对比了仿真结果与实验结果,发现仿真结果符合实际检测情况.结果表明超声波有限元仿真方法可以用于缺陷的定量与定位分析,为实际检测复杂的工况提供了可靠的评判依据.

Ultrasonic testing is a generally used nondestructive testing method, the results of which are abstract because the complex transmission path of ultrasonic contains a variety of noise signals, and the defect signals mixing with a large number of noises are difficult to be identified. We investigated the ul-trasonic mechanism of time of flight diffraction（TOFD） by finite element analysis for the better applica-tions of ultrasonic detection technology. Firstly, the welding steel with the artificial defects was detec-ted by TOFD method and the detection signals with the noise were extracted in experiments. Secondly, the propagation of ultrasound in artificial defect test block was simulated by ANSYS software and mo-reover the model of the finite element analysis was established to identify the defect diffraction signals accurately. Finally, the simulation results were compared with the experimental results, which showed the similarity of the values of simulation and actual detection. The research suggests that ultrasonic wave propagation simulation can be used for quantitative analysis and position to defects, which pro-vides reliable judgment basis for the actual test of complex conditions.