声波散射在焊接板结构超声导波合成孔径阵列成像中的作用

为揭示声波散射在焊接板结构超声导波合成孔径阵列成像中的作用机制，将散射回波矩阵和散射渡越时间矩阵用于分析描述超声水平剪切（shear horizontal，SH）导波声波散射，探讨了焊缝散射和边界散射在导波成像中的作用关系.结果表明，散射矩阵是揭示声波散射在超声导波阵列成像作用机制的有效工具，散射回波矩阵与散射渡越时间矩阵具有相同的散射矩阵因子，导波图像出现与散射矩阵因子成倍数关系的“条带”伪像，图像椭圆簇轨迹特征复杂化，图像背景噪声增强，图像信噪比减小.研究工作可为深入开展焊接板结构超声导波非直线阵列成像算法研究提供基础.

Action mechanism of acoustic scattering in synthetic aperture array imaging of ultrasonic guided waves in plate with welding structures

In order to discover the action mechanism of acoustic scattering in synthetic aperture array imaging of ultrasonic guided waves in plate with welding structures, the scattering amplitude matrix (SAM) and the scattering flight time matrix (SFTM) were proposed to analyze and describe the acoustic scattering of ultrasonic shear horizontal(SH) guided waves, the action relationship between the weld scattering and the boundary scattering were researched emphatically. The research result shows that, the scattering matrix may be a forceful analysis tool that may be used into discovering the action mechanism of acoustic scattering in synthetic aperture array imaging of ultrasonic guided waves, the SAM and the SFTM have the same scattering matrix factor that lead to pseudo strip-shaped shadows with the same degree and the characteristic of elliptical cluster tracks in array image, and then the background noise of image may increase and signal-nose ratio may decrease accordingly. The research work proposed would provide support for no-line array imaging algorithm of ultrasonic guided waves in plates with welded structure.