| 刘婉婷,罗云跃,杜好阳,朱大铭,吴刚,王凯.螺旋型电磁超声辐射声场对缺陷检测影响的 计算机模拟*[J].,2023,42(4):737-745 |
| 螺旋型电磁超声辐射声场对缺陷检测影响的 计算机模拟* |
| Computer simulation of spiral electromagnetic acoustic transducers radiated sound field influence on defect detection |
| 投稿时间：2022-09-16 修订日期：2023-07-03 |
| 中文摘要: |
| 电磁超声(EMAT)作为一种非接触超声检测技术，已得到了普遍的关注和研究。然而，EMAT目前只得到了一些有限的应用，尤其在缺陷探伤应用方面还不能替代压电超声，深入探究其原因并加以改进，对推动EMAT在缺陷检测方面的应用具有重要意义。利用有限元方法建立了螺旋型EMAT模型，分析了其辐射声场和声场特征；通过将有限元计算所得到的洛伦兹力分布简化为门函数，并结合格林函数法，得到了螺旋型EMAT辐射声场的简化解析结果。这些方法可用于计算螺旋型EMAT辐射声场指向性以及在缺陷检测中比较关心的一些特征参数，如扩散角、偏离角等参数。通过螺旋型EMAT辐射声场实验，验证了理论分析结果。通过与压电超声检测理论与实验的对比，研究认为：螺旋型EMAT辐射声场的具有横波和纵波等多种波模及多种模态转换的特点，以及相对复杂的异型声场几何分布等复杂特性，使其在缺陷检测应用方面受到局限。这些研究方法对改进EMAT设计，优化控制EMAT辐射声场，拓展EMAT在缺陷检测方面的应用具有参考价值。 |
| 英文摘要: |
| As a non-contact ultrasonic testing technology, electromagnetic acoustic transducers (EMAT) has received extensive attention and research. Although being used in some applications, EMAT can still not replace the piezoelectric ultrasonic testing in flaw detection. It is meaningful to promote the application of EMAT in defect detection by in-depth study of its causes. At first, by establishing finite element method(FEM) model of spiral EMAT, this paper shows its field radiation pattern and characteristics. Next, by simplifying FEM generated Lorentz force distribution into the gate function and applying the Green’s function method, the simplified analytic model of spiral EMAT is presented. These methods can be used to calculate the field radiation directivity of the spiral EMAT and some characteristic parameters which are concerned in the defect detection, such as diffusion angle, deviation angle and so on. By comparing with piezoelectric ultrasonic testing, there are complex modes such as transverse wave and longitudinal wave, mode conversion wave and heterogeneous field distribution, which result in the complexity of spiral EMAT ultrasonic field and limited EMAT in defect detection applications. These methods are valuable for improving the design of EMAT, optimizing the control of EMAT radiation field, and expanding the application of EMAT in defect detection. |
| DOI：10.11684/j.issn.1000-310X.2023.04.009 |
| 中文关键词: 螺旋型EMAT 辐射声场 计算机模拟 格林函数 缺陷检测 |
| 英文关键词: Spiral EMAT Radiated sound field Computer Simulation Green''s function Defect detection |
| 基金项目: |
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