Influence of porosity on ultrasonic wave velocity, attenuation and interlaminar interface echoes in composite laminates: Finite element simulations and measurements
Influence of porosity on ultrasonic wave velocity, attenuation and interlaminar interface echoes in composite laminates: Finite element simulations and measurements
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DOI：
10.1016/j.compstruct.2016.05.054
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发表时间：
2016-09-15
影响因子：
6.3
通讯作者：
Kuraishi, Akira
中科院分区：
文献类型：
--
作者：
Ishii, Yosuke;Biwa, Shiro;Kuraishi, Akira
基于二维有限元分析和测试，研究了单向碳纤维增强复合材料层合板中孔隙率对超声波传播的影响。分析中考虑了不同孔隙含量和大小的随机分布，以及粘弹性层和层间树脂富集区的影响。瞬态反射波形计算从频域有限元解的逆傅立叶变换。作为孔隙率表征的措施，超声波的速度，衰减系数，和层间界面回波特性进行了检查24层单向复合材料层合板。结果，波速以对孔径不敏感的方式随着孔隙度含量而减小。另一方面，衰减系数随着孔隙率含量和孔径的增加而增加。反射波形的时频分析表明，层间界面回波在阻带频率的时间衰减率是孔隙含量的一个很好的指标。当层间界面刚度根据孔隙率含量进行调整时，通过数值模拟更好地再现了测得的波速的孔隙率含量依赖性，这表明不仅孔隙率特征而且层间界面性质随固化条件而变化。(C)2016爱思唯尔有限公司版权所有。
The influence of porosity on the ultrasonic wave propagation in unidirectional carbon-fiber-reinforced composite laminates is investigated based on the two-dimensional finite element analysis and measurements. Random distributions of pores with different contents and size are considered in the analysis, together with the effects of viscoelastic plies and interlaminar resin-rich regions. The transient reflection waveforms are calculated from the frequency-domain finite-element solutions by the inverse Fourier transform. As the measures for porosity characterization, the ultrasonic wave velocity, attenuation coefficient, and interlaminar interface echo characteristics are examined for 24-ply unidirectional composite laminates. As a result, the wave velocity decreases with the porosity content in a manner insensitive to the pore size. On the other hand, the attenuation coefficient increases both with the porosity content and with the pore size. The time-frequency analysis of the reflection waveforms shows that the temporal decay rate of interlaminar interface echoes at the stop-band frequency is a good indicator of the porosity content. The measured porosity-content dependence of the wave velocity is better reproduced by the numerical simulations when the interlayer interfacial stiffnesses are adjusted according to the porosity content, indicating that not only the porosity features but also the interlaminar interfacial properties vary with curing conditions. (C) 2016 Elsevier Ltd. All rights reserved.