Ishii Yosuke, Biwa Shiro
Department of Aeronautics and Astronautics, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8540, Japan.
J Acoust Soc Am. 2014 Jul;136(1):183-91. doi: 10.1121/1.4881920.
An ultrasonic evaluation procedure for the interlayer interfacial normal stiffness and the intralayer longitudinal wave velocity of multilayered plate-like structures is proposed. Based on the characteristics of the amplitude reflection spectrum of ultrasonic wave at normal incidence to a layered structure with spring-type interlayer interfaces, it is shown that the interfacial normal stiffness and the longitudinal wave velocity in the layers can be simultaneously evaluated from the frequencies of local maxima and minima of the spectrum provided that all interfaces and layers have the same properties. The effectiveness of the proposed procedure is investigated from the perspective of the sensitivity of local extremal frequencies of the reflection spectrum. The feasibility of the proposed procedure is also investigated when the stiffness of each interface is subjected to small random fluctuations about a certain average value. The proposed procedure is applied to a 16-layered cross-ply carbon-fiber-reinforced composite laminate. The normal stiffness of resin-rich interfaces and the longitudinal wave velocity of plies in the thickness direction evaluated from the experimental reflection spectrum are shown to be consistent with simple theoretical estimations.
提出了一种用于评估多层板状结构层间界面法向刚度和层内纵波速度的超声评估方法。基于超声波垂直入射到具有弹簧型层间界面的层状结构时的振幅反射谱特性，结果表明，只要所有界面和层具有相同的特性，就可以从谱的局部最大值和最小值频率同时评估界面法向刚度和层内纵波速度。从反射谱局部极值频率的灵敏度角度研究了所提方法的有效性。当每个界面的刚度在某个平均值附近受到小的随机波动时，也研究了所提方法的可行性。将所提方法应用于一个16层的交叉铺层碳纤维增强复合材料层压板。从实验反射谱评估得到的富树脂界面的法向刚度和厚度方向各层的纵波速度与简单的理论估计结果一致。
