New nonlinear ultrasonic method for material characterization: Codirectional shear horizontal guided wave mixing in plate
New nonlinear ultrasonic method for material characterization: Codirectional shear horizontal guided wave mixing in plate
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DOI：
10.1016/j.ultras.2019.04.001
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发表时间：
2019-07-01
期刊：
影响因子：
4.2
通讯作者：
Cheng, Li
中科院分区：
文献类型：
--
作者：
Shan, Shengbo;Hasanian, Mostafa;Cheng, Li
提出了一种基于一组新发现的波三联体的非线性超声方法，其中两个主要的同向剪切-水平SHO波在弱非线性板中混合，并在和频处产生累积SO Lamb波。理论分析表明，当两个主SHO波的频率之和等于SHO模与SO Lamb波模相交的频率时，两个主SHO波的任意组合都会产生内共振的次级SO Lamb波。揭示了频率组合与非线性兰姆波产生效率之间的关系，为进一步的工程应用提供了指导。有限元验证进行了减法的非线性特征提取的援助。的累积效应所产生的SO兰姆波在和频率以及非线性兰姆波产生效率的频率组合的影响被证实。实验进行验证所提出的方法，以及证明其用于材料表征。实验中需要使用凝胶滤波器来消除非线性源的影响。利用凝胶滤波器验证了二次SO Lamb波的累积效应，提取了相应的斜率，并进一步用于表征疲劳样品的材料状态。结果表明，该方法对早期疲劳损伤具有较高的灵敏度，具有良好的应用前景。
A nonlinear ultrasonic method is proposed based on a group of newly discovered wave triplets where two primary codirectional shear-horizontal SHO waves mix in a weakly nonlinear plate and generate a cumulative SO Lamb wave at the sum frequency. Theoretical analyses show that any combination of two primary SHO waves whose frequencies sum to the frequency at which the SHO mode intersects the SO Lamb wave mode results in an internally resonant secondary SO Lamb wave. Moreover, the relationship between the frequency combination and the nonlinear Lamb wave generation efficiency is revealed, which guides further engineering applications. Finite element validations are carried out with the aid of a subtraction method for the nonlinear feature extraction. The cumulative effect of the generated SO Lamb wave at the sum frequency as well as the influence of the frequency combinations on the nonlinear Lamb wave generation efficiency is confirmed. Experiments are performed to validate the proposed method as well as demonstrate its use for material characterization. The experiments require a gel filter to mitigate the influence of the undesired nonlinear sources. With the gel filter, the cumulative effect of the secondary SO Lamb wave is verified and the corresponding slope is extracted and further used to characterize the material status of the fatigue samples. Results demonstrate the proposed method provides high sensitivity to early fatigue damage, which makes it promising for the further early damage detection applications.