On the detection of fatigue damage in composites by use of second harmonic guided waves
On the detection of fatigue damage in composites by use of second harmonic guided waves
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DOI：
10.1016/j.compstruct.2016.05.049
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发表时间：
2016-09-15
影响因子：
6.3
通讯作者：
Kuehnrich, Tim
中科院分区：
文献类型：
--
作者：
Rauter, Natalie;Lammering, Rolf;Kuehnrich, Tim
在复合材料结构中，循环加载甚至在早期阶段就会导致微结构损伤。这种损害会随着寿命的推移而增长，最终可能会导致灾难性的故障。在这项研究中，基于累积二次谐波兰姆波的非线性波传播被用来检测微结构损伤和相应的材料退化。结果表明，相对声学非线性参数越大，杨氏模数越小。通过对非线性波传播的数值模拟和杨氏模数的测定，对这一结果进行了更详细的分析。因此，在具有接触边界条件的波导上添加了显微镜检测到的损伤材料中的水平裂纹。数值分析表明，由于波和裂纹的相互作用，产生了更高的简谐振型，并且随着裂纹尺寸和数目的增加，非线性效应越来越大。由于刚性不受水平裂纹的影响，杨氏模量的下降被认为与材料退化等不可见的损伤有关，这也导致了波传播的非线性效应增加。综上所述，相对声学非线性参数可以作为材料退化的指示器，从而用于微结构损伤的监测。(C)2016爱思唯尔有限公司。保留所有权利。
In composite structures cyclic loading leads to micro-structural damage even at an early stage. This damage grows over lifetime and may finally cause catastrophic failure. In this study nonlinear wave propagation based on the cumulative second harmonic Lamb wave generation is used to detect microstructural damage and the corresponding material degradation experimentally. It is shown that an increasing relative acoustical nonlinearity parameter indicates a decreasing Young's modulus. This result is analyzed more in detail by numerical simulations of the nonlinear wave propagation as well as by Young's modulus determination. Therefore, horizontal cracks, detected by microscopy in damaged material, are added to the waveguide with contact boundary conditions. The numerical analysis shows a higher harmonic mode generation due to the interaction of the waves and the cracks and an increasing nonlinear effect with increasing crack sizes and numbers. Since the stiffness is not affected by horizontal cracks the decreasing Young's modulus is assumed to be related to non-visible damage like material degradation, leading also to an increasing nonlinear effect of the wave propagation. In conclusion, the relative acoustical nonlinearity parameter can be used as an indicator of the material degradation and, therefore, for monitoring of micro-structural damage. (C) 2016 Elsevier Ltd. All rights reserved.