A quantitative comparison of the capabilities of in situ computed tomography and conventional computed tomography for damage analysis of composites
A quantitative comparison of the capabilities of in situ computed tomography and conventional computed tomography for damage analysis of composites
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DOI：
10.1016/j.compscitech.2015.01.020
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发表时间：
2015-04-06
影响因子：
9.1
通讯作者：
Hufenbach, W.
中科院分区：
文献类型：
--
作者：
Boehm, R.;Stiller, J.;Hufenbach, W.
原位层析成像是研究材料加载过程中损伤现象的一种强有力的无损检测方法。然而，卸载标本后检测到的损伤量与传统CT扫描相比的差异到目前为止还没有报道，因此是本研究的重点。为此，对三种不同的纺织增强复合材料进行了实验研究。对多层平床纬编织物和多轴向无卷曲织物的碳纤维增强环氧复合材料进行了单轴拉伸试验。分别在不同负荷水平下进行原位CT扫描，并在卸载后进行常规CT扫描。实验表明，由于卸载过程中的裂纹闭合效应，加载时观察到的裂纹长度和分层面积明显较大。因此，任何损坏诊断都应在负载下执行。第三个例子是编织增强的陶瓷C/C复合材料。该复合材料是通过厚度方向的压缩加载的。结果表明，总孔隙率随载荷的增加而减小，只能通过原位CT测量来预测。(C)2015爱思唯尔有限公司。保留所有权利。
The so called in situ computed tomography is a powerful non-destructive testing method to study the damage phenomenology while a material is loaded. However, the difference in the detected amount of damage compared to conventional CT scans after unloading of the specimen has not been reported so far and is therefore the focus of this study. Three different textile-reinforced composite materials have been experimentally investigated for that purpose. Carbon fibre reinforced epoxy composites with multi-layered flat bed weft-knitted fabrics and multi-axial non-crimp fabrics were uniaxially loaded in tension. In situ CT scans were taken at different load levels and conventional CT scans after unloading. The experiments have shown that the observed crack lengths and delaminated areas are significantly larger while the load is applied because of crack closure effects during unloading. Any damage diagnosis should therefore be performed under load. A ceramic C/C composite with woven reinforcement was taken as a third example. This composite was loaded by compression in thickness direction. It was found that the decrease of total porosity with increasing load can only be predicted by in situ CT measurements. (C) 2015 Elsevier Ltd. All rights reserved.