Page 37 - 《应用声学》2022年第4期
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第 41 卷 第 4 期                                                                       Vol. 41, No. 4
             2022 年 7 月                          Journal of Applied Acoustics                      July, 2022

             ⋄ 研究报告 ⋄



                激光超声的多模式合成孔径聚焦成像仿真分析                                                                    ∗





                                钟 华     1   孙凯华     1†   孙 铭    2   黄姝珂      1  周英平      3


                                        (1 中国工程物理研究院机械制造工艺研究所           绵阳   621999)
                                               (2 南京理工大学理学院      南京   210094)
                                               (3 绵阳第一军事代表室      绵阳   621900)

                摘要：针对激光超声体波在检测材料内部缺陷时反射信号弱、信噪比较差的问题，提出了一种基于激光超声的
                多模式合成孔径聚焦成像方法。通过耦合激光激发超声方向性、干涉仪探测超声方向性、超声波与缺陷作用后
                声场分布方向性得到声场灵敏度图，再根据声场灵敏度图和不同模式波的传播特性预测不同位置分布缺陷的
                最佳成像模式波，从而使用多模组合的合成孔径聚焦成像方法对缺陷成像。使用有限元方法对该成像过程进
                行数值模拟来验证其可行性，成像结果与理论预测一致。采用这一缺陷成像方法可减小盲区，消除伪像，从而
                提高图像质量。
                关键词：合成孔径聚焦成像技术；激光超声；内部缺陷；方向性；多模组合成像
                中图法分类号: TG115.28           文献标识码: A          文章编号: 1000-310X(2022)04-0535-13
                DOI: 10.11684/j.issn.1000-310X.2022.04.005


                  Simulation analysis of multi-mode synthetic aperture focusing technique
                                              based on laser ultrasound



                       ZHONG Hua   1   SUN Kaihua 1  SUN Ming  2  HUANG Shuke   1  ZHOU Yingping  3

                 (1 Institute of Mechanical Manufacturing Process, China Academy of Engineering Physics, Mianyang 621999, China)
                           (2 School of Science, Nanjing University of Science and Technology, Nanjing 210094, China)
                                 (3 Mianyang First Military Representative Office, Mianyang 621900, China)

                 Abstract: To deal with the weak reflection signal and poor signal to noise ratio in the detection of internal
                 defects via laser ultrasound, we proposed a multi-mode synthetic aperture focusing technique (SAFT) based on
                 laser ultrasound. By coupling the directivity of laser exciting ultrasound, interferometer detecting ultrasound
                 and ultrasonic filed interacting with defects, we can obtain the sensitivity image, then based on the sensitivity
                 image and characteristic of different waves, the most suitable mode for defects in different locations can be
                 determined. Finally, using the multi-mode combination SAFT to image defects. This imaging method is
                 simulated numerically by the finite element method to verify its feasibility, simulation results coincide well with
                 the theoretical prediction. The proposed imaging method can reduce blind areas, eliminate fake images and
                 improve the image quality.
                 Keywords: Synthetic aperture focusing technique; Laser ultrasound; Internal defects; Directivity; Multi-mode
                 combination imaging


             2021-05-31 收稿; 2021-09-07 定稿
             国家自然科学基金项目 (61801451)
             ∗
             作者简介: 钟华 (1997– ), 男, 四川成都人, 硕士研究生, 研究方向: 激光超声缺陷检测。
              通信作者 E-mail: sundoom@126.com
             †
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