Application of Ultrasonic Coda Wave Interferometry for Micro-cracks Monitoring in Woven Fabric Composites
Application of Ultrasonic Coda Wave Interferometry for Micro-cracks Monitoring in Woven Fabric Composites
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DOI：
10.1007/s10921-019-0563-z
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发表时间：
2019-03
影响因子：
2.8
通讯作者：
P. Pomarède;L. Chehami;N. Declercq;F. Meraghni;Junliang Dong;A. Locquet;D. Citrin
中科院分区：
文献类型：
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作者：
P. Pomarède;L. Chehami;N. Declercq;F. Meraghni;Junliang Dong;A. Locquet;D. Citrin
四点弯曲试验的后果，高达12毫米，检查通过发射1 MHz的超声导波在编织碳纤维增强聚合物试样，使用尾波干涉法（CWI），揭示了潜在的用途，无损评价。它是已知的，CWI是更敏感的实际损伤比传统的方法的基础上的第一个到达时间的飞行在地球物理，或在土木工程应用，如混凝土结构。然而，在复合材料中，由于所涉及的结构复杂性，CWI还没有很好地建立。在本文中，CWI的监测发生的现实缺陷，如微裂纹的编织碳纤维复合材料板。通过四点弯曲试验产生微裂纹。通过逐渐增加载荷水平，损伤状态逐步增强，直到失效开始。每次加载后，使用超声波监测损坏情况。它表明，CWI是一个强大的工具来检测损伤，即使是低水平，在样品中。基于CWI的两种损伤指标，即信号相关系数和相对速度变化，进行了研究，并出现互补。在显著载荷水平下，受损样本和健康样本（参考0 mm）中记录的波形之间的归一化互相关系数急剧下降;因此，第一个指标可用于严重损伤检测。它还表明，通过第二个指标，在零负载时采取的基线信号之间的相对速度变化，并在各种负载下采取的信号，是线性的负载的函数，直到达到临界水平，因此，第二个指标，是有用的低损伤水平检测。相对速度测量的演变得到支持的相对比较的位移函数的弯曲模量的演变。相对速度的变化表现出相同的演变与加载的弯曲模量。它可用于指示材料刚度何时显著降低。该研究是在复合材料制造质量控制的框架内进行的，似乎是一种很有前途的检测技术。
The consequences of a four-point bending test, up to 12 mm, are examined by emitting 1 MHz ultrasonic guided waves in woven carbon fiber reinforced polymer specimens, using coda wave interferometry (CWI), revealing a potential use for nondestructive evaluation. It is known that CWI is more sensitive to realistic damage than the conventional method based on the first arriving time of flight in geophysical, or in civil engineering applications such as concrete structures. However, in composite materials CWI is not well established because of the involved structural complexity. In this paper, CWI is investigated for monitoring the occurrence of realistic defects such as micro-cracks in a woven carbon fiber composite plate. The micro-cracks are generated by a four-point bending test. The damage state is stepwise enhanced by gradually increasing the load level, until failure initiation. The damage is monitored, after each loading, using ultrasound. It is demonstrated that CWI is a powerful tool to detect damage, even low levels, in the sample. Two damage indicators based on CWI, i.e. signals correlation coefficient and relative velocity change, are investigated and appear to be complimentary. Under significant loading levels, the normalized cross-correlation coefficient between the waveforms recorded in the damaged and in the healthy sample (reference at 0 mm), decreases sharply; this first indicator is therefore useful for severe damage detection. It is also demonstrated, by means of a second indicator, that the relative velocity change between a baseline signal taken at zero loading, and the signals taken at various loadings, is linear as a function of the loading, until a critical level is reached; therefore this second indicator, is useful for low damage level detection. The obtained evolution of the relative velocity measurement is supported by relative comparison to the evolution of the bending modulus in function of displacement. The relative velocity change exhibits the same evolution as the bending modulus with loading. It could be used to indicate when the material stiffness has decreased significantly. The research is done in the framework of composite manufacturing quality control and appears to be a promising inspection technique.