超薄双层复合结构界面特性超声兰姆波评价方法

提出超声兰姆波方法来评价超薄双层复合结构界面联接特性 ,这里“超薄”的概念是指层厚度 h远小于层中的声波波长λ,导致采用脉冲回波方法时 ,在时域上层前后界面的各次回波信号相互混迭。分析了超薄双层复合结构界面处于刚性联接、滑移联接和完全脱层 3种情况下超声兰姆波的色散特性 ,提出了以色散曲线为依据的超声兰姆波界面特性评价方法 ,进一步分析了影响方法估计准确性的各种因素。

ULTRASONIC GUIDED WAVE METHOD FOR EVALUATING THE INTERFACE BONDING PROPERTY OF ULTRA-THIN TWO-LAYER COMPOSITES

An ultrasonic guided wave method suitable for evaluating the interfacial bonding property of the ultra thin two layer composite is presented. The “ultra thin” here means that the thickness of the layer is only a fraction of the ultrasound wavelength so that the echoes from the front and back surfaces cannot be separated in the time domain. The interfacial bonding condition of the ultra thin two layer composites is estimated by using the dispersion properties of the ultrasonic guided waves propagating through it. The reasons for evaluation error of the parameters and the sensitivity of the method are analyzed. In experimental study the technique is employed to characterize the interface properties of the ultra thin aluminum/brass composite with thickness down to 10 percent of the ultrasonic wavelength with a pair of broadband 2MHz longitudinal wave transducers. It is observed that the agreement between the nominal value and the estimation is excellent.