Aiming at the difficult problem of detecting internal defects in the second phase of non-uniform structure,by establishing different types of heterogeneous steel non-uniform weld models and mechanical wave interface propagation models,and based on the difference in grain size of heterogeneous materials,the direction of ultrasonic sound beam propagation at the interface of non-uniform materials is changed.The formula for determining the change in incidence angle and wave velocity is derived and calculated,and then the defect displacement position during the detection of non-uniform materials is derived,resulting in low-frequency attenuation scattering is weak and focusing ability is strong.The penetration and focusing ability of longitudinal wave is stronger than that of transverse wave,and scattering is weak.Moreover,the attenuation of longitudinal wave is faster than that of transverse wave.In coarse-grained non-uniform materials,the detection depth is shallower and more remote than the actual depth.In the actual detection process,selecting low-frequency self focusing shear waves can achieve the detection of internal defects in non-uniform materials.
关键词
非均匀组织/机械波界面/低频/纵波/自聚焦
Key words
non uniform tissue/mechanical wave interface/low frequency/longitudinal wave/self focusing
维普
万方数据