The evaluation of internal damage in multilayered composite materials is of great importance for high reliability-demanding applications, and remains a challenge due to the complex failure modes and mechanism of composite materials. This study presents a volumetric method of three-dimensional size quantification and prediction for low velocity impact damage in thin composite plates using phased-array ultrasound. A set of low velocity impact damages are induced in thin carbon fiber/epoxy resin matrix composite plates using quasi-static indentation tests. A volumetric reconstruction method is proposed to reconstruct a three-dimensional volume from the raw data, allowing for direct damage identification, localization, and quantification. Using the echo amplitude feature of the reconstructed volume, the 6 dB-drop method is employed to characterize the damage size in terms of volumes and areas. An impact size prediction model is established to correlate the impact energy and the damage volume/area. Comparisons are made between the microscopy measurement of the damage cross-section and results obtained using the developed method.

中文翻译：

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使用相控阵超声对复合薄板低速冲击损伤进行三维损伤量化

多层复合材料内部损伤的评估对于高可靠性要求的应用非常重要，并且由于复合材料的复杂失效模式和机制仍然是一个挑战。本研究提出了一种使用相控阵超声对薄复合板中的低速冲击损伤进行三维尺寸量化和预测的体积方法。使用准静态压痕测试在薄碳纤维/环氧树脂基复合材料板中引起一组低速冲击损伤。提出了一种体积重建方法，从原始数据重建三维体积，允许直接损伤识别、定位和量化。利用重建体积的回波幅度特征，6 dB-drop 方法用于根据体积和面积来表征损伤大小。建立冲击尺寸预测模型以关联冲击能量和损伤体积/面积。对损伤截面的显微镜测量与使用开发的方法获得的结果进行了比较。