Optimal Excitation Frequency of Lamb Waves for Delamination Detection in CFRP Laminates
Optimal Excitation Frequency of Lamb Waves for Delamination Detection in CFRP Laminates
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DOI：
10.1177/0021998309353965
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发表时间：
2010-06
影响因子：
2.9
通讯作者：
N. Hu;Y. Liu;Y. Li;X. Peng;B. Yan
中科院分区：
文献类型：
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作者：
N. Hu;Y. Liu;Y. Li;X. Peng;B. Yan
为了提高基于兰姆波的碳纤维增强塑料（CFRP）复合材料层合板脱层检测技术的可靠性，研究了正交铺层CFRP脱层梁中兰姆波激励频率对脱层反射波强度的影响。虽然本文的结论也适用于S0模式，但选择了A0兰姆波模式。采用作者提出的Chebyshev拟谱Mindlin板元模拟了A0模的传播及其与脱层的相互作用。数值结果表明，在不同频率下，A0模态对脱层的敏感性有显著差异。沿着层压件的整个厚度方向具有不同长度或不同位置的每个层离通常具有至少一个或多个最佳激励频率，其可以从层离产生最强的反射波信号。通过分析局部上下分层区域的固有振动，探讨了产生这种现象的原因。最佳激励频率被确定为接近的共振频率的局部脱层区域的纯弯曲振动模式类似的A0模式的变形模式。
To improve the reliability of delamination detection techniques based on Lamb waves for carbon fibre reinforced plastics (CFRP) composite laminates, the influence of excitation frequency of Lamb waves on the intensity of reflected waves from a delamination in cross-ply CFRP delaminated beams was investigated. The A0 Lamb wave mode was chosen although the conclusion in this work is also applicable to S0 mode. A Chebyshev pseudospectral Mindlin plate element proposed by authors was employed to simulate the A 0 mode propagation and the interaction of the A0 mode with the delamination. Numerical results show that the sensitivity of A0 mode to the delamination at different frequencies is remarkably different. Each delamination with different lengths or different locations along the through-thickness direction of the laminates generally has at least one or more optimal excitation frequencies which can generate the strongest reflected wave signals from the delamination. The reason for this phenomenon was also investigated by analyzing the natural vibration of the local upper- and lower-delaminated regions. The optimal excitation frequencies were identified to be close to the resonant frequencies of the local delaminated regions with pure flexural vibration modes similar to the deformation pattern of A0 mode.