Imaging of Impact Damage in Composite Materials
Imaging of Impact Damage in Composite Materials
复制标题
复合材料冲击损伤的成像
DOI：
10.1007/978-1-4613-0979-6_26
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发表时间：
1988
期刊：
影响因子：
--
通讯作者：
K. Shimmin
中科院分区：
文献类型：
--
作者：
B. Frock;R. W. Martin;T. J. Moran;K. Shimmin
传统的超声波 C 扫描图像是根据在 A 扫描的低通滤波和校正版本上放置在特定时间位置的“门”内获取的信息生成的。将门放置在与界面相对应的时间位置允许检查界面的完整性。然而，如果界面间隔很近，就像准各向同性石墨/环氧树脂复合材料的情况一样，由于超声波脉冲的持续时间有限，上层的信息会模糊到下层。这会产生较低的信号与背景电平比，从而导致第一个界面处及其下方的模糊。
Conventional ultrasonic C-scan images are generated from information acquired within “gates” placed at specific temporal locations on low-pass filtered and rectified versions of A-scans. Placing the gates at temporal locations which correspond with interfaces allows the integrity of the interfaces to be examined. However, if the interfaces are closely spaced, as is the case for quasi-isotropic graphite/epoxy composites, the information from upper layers is blurred into the layers below because of the finite time duration of the ultrasonic pulse. This creates a low signal-to-background-level ratio, which causes blurring at and below the first interface.