摘要
研究了一种应用恢复函数和低频超声波对超薄层弹性材料的声学特性（厚度、声速和密度）进行无损测量的新方法。这里所说的"超薄"是指材料的厚度远小于检测所用的声波波长。文中对应用透射恢复函数的幅度谱、相位谱和复谱在最小二乘意义下估计材料的定征参数的性能进行了详细的研究和比较，分析了影响估计准确性的典型因素，推导和讨论了灵敏度函数及其在误差传递中的意义．实验使用中心频率为2MHz的超声波测量厚度为25．4～152．4μm的铜箔，得到的估计值与真实值符合的非常好．
Combining frequency domain retrieve function with low frequency ultrasound, a method is presented in this paper for characterizing ultra-thin plate. By 'ultra-thin', we mean the thickness of specimen is much less than wavelength. The through-transmission retrieve function is examined in detail. In conjunction with the method of least squares) the amplitude spectrum, phase spectrum and complex spectrum are all being used to determine the best estimation, respectively. An analysis of some typical sources of the estimate deviation is presented. The sensitivity of the retrieve function to acoustical parameters and its significance in the propagation of errors have been carried out and well discussed.In experimental study the technique is employed to characterize the brass sheets ranging from 25.4 μm to 152.4 μm with a broadband 2 MHz center frequency transducer. It is observed that the agreementbetween the nominal value and the estimation is excellent.
出处
《声学学报》
EI
CSCD
北大核心
1999年第1期71-80,共10页
Acta Acustica
基金
中国国家教委跨世纪人才基金
