Page 60 - 《应用声学》2021年第6期

第 40 卷 第 6 期 Vol. 40, No. 6
2021 年 11 月 Journal of Applied Acoustics November, 2021

⋄ 研究报告 ⋄

幅度调制的非线性超声相控阵成像方法 ∗

刘志勇 滕 达 项延训 †

(华东理工大学 上海 200237)

摘要：超声相控阵是超声检测领域常用的材料缺陷定位和成像技术，可便捷快速地对裂纹、孔洞等缺陷进行成
像。但是，传统超声相控阵方法对较小缺陷如闭合裂纹不太敏感。非线性超声信号因对材料性能退化以及微
小缺陷敏感而广受关注。该文针对疲劳闭合裂纹检测，提出一种基于幅度调制的非线性超声相控阵成像方法，
通过测量物理聚焦和虚拟聚焦两种聚焦模式下超声扩散场中的声能差，并将其作为非线性参量，实现疲劳裂
纹闭合部分的定位成像和定量表征。将该法应用于 7075 铝合金试样疲劳裂纹的实验测量，并研究了扩散场信
号延迟时间对非线性超声相控阵成像结果的影响。结果表明：相较于传统超声相控阵全聚焦法，基于幅度调制
的非线性超声相控阵成像方法能够更准确地定位和成像疲劳裂纹闭合部分；延迟时间的选择对疲劳裂纹长度
的表征精度影响较大，该文研究了该延迟时间的选择方法并实现了检测结果的优化。
关键词：非线性超声成像；相控阵；幅度调制；闭合裂纹
中图法分类号: TB559 文献标识码: A 文章编号: 1000-310X(2021)06-0856-09
DOI: 10.11684/j.issn.1000-310X.2021.06.007

Research on nonlinear ultrasonic phased array imaging based on amplitude
modulation

LIU Zhiyong TENG Da XIANG Yanxun

(East China University of Science and Technology, Shanghai 200237, China)
Abstract: Ultrasonic phased array is a common material defect location and imaging technology in ultrasonic
testing, which can quickly image defects like cracks, holes. However, traditional ultrasonic phased array method
is less sensitive to smaller defects such as closed cracks. Nonlinear ultrasonic signals are widely concerned
because of their sensitivity to material degradation and minor defects. Aiming at the detection of fatigue
closed cracks, this paper proposes a nonlinear ultrasonic phased array imaging method based on amplitude
modulation, which measures the sound energy difference in the ultrasonic diffusion field under two focusing
modes of physical focus and virtual focus, and uses the sound energy difference as the nonlinear parameter
to realize the positioning imaging and quantitative characterization of the closed part of fatigue crack. The
method was applied to the experimental measurement of fatigue cracks of 7075 aluminum alloy specimen, and
the influence of the diffusion field signal delay on the results of nonlinear ultrasonic phased array imaging was
studied. The results show that compared with the full focusing method commonly used in ultrasonic phased
array, the nonlinear ultrasonic phased array imaging method can locate and image the closed part of fatigue
crack more accurately. The choice of delay time has a great influence on the accuracy of fatigue crack length
characterization. This paper studies the choice of delay time and optimizes the detection results.
Keywords: Nonlinear ultrasonic imaging; Phased array; Amplitude modulation; Closed crack

2021-01-08 收稿; 2021-04-07 定稿
国家自然科学基金项目 (U1930202)
∗
作者简介: 刘志勇 (1995– ), 男, 河北邢台人, 硕士研究生, 研究方向: 超声相控阵成像。
† 通信作者 E-mail: yxxiang@ecust.edu.cn