Even though the pulse-echo ultrasonic technique is commonly used for the assessment of metal structures, it has some inherent limitations. Vibro-acoustography (VA) is a relatively new ultrasonic technique which has demonstrated a great potential in revealing defects in objects, however it is traditionally used to analyze the integrity of specimens made of low-stiffness materials. This work presents the evaluation of the performance of VA technique for the inspection of a steel structure, which was manufactured with defects of known geometry on its inner surface. All the inspection process was done automatically, from the data acquisition to the image processing for characterizing the defects. Experimental results show that VA was able to identify and characterize even the smallest defects in the structure, with a diameter of 2 mm. In addition, the results show that VA was able to characterize the artificial defects in the steel structure with almost the same errors as the traditional pulse-echo method, which indicates a potential use of VA in the inspection of materials with high mechanical stiffness.

中文翻译：

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使用音爆振动声学无损检测金属样品

尽管脉冲回波超声技术通常用于评估金属结构，但它也有一些固有的局限性。振动声学 (VA) 是一种相对较新的超声波技术，在揭示物体缺陷方面显示出巨大潜力，但它传统上用于分析由低刚度材料制成的样品的完整性。这项工作对 VA 技术在钢结构检测方面的性能进行了评估，该钢结构的内表面存在已知几何形状的缺陷。从数据采集到用于表征缺陷的图像处理，所有检测过程都是自动完成的。实验结果表明，即使是直径为 2 毫米的结构中最小的缺陷，VA 也能够识别和表征。此外，