Two inverse methods for characterization of an inaccessible thin film under a plate by low-frequency ultrasound  

作　　者：WANG Yang MAO Jie LI Mingxuan WANG Xiaomin 

机构地区：[1]National Laboratory of Acoustics,Institute of Acoustics,Chinese Academy of Sciences Beijing 100190

出　　处：《Chinese Journal of Acoustics》2010年第3期230-241,共12页声学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(No.10474113 and No.10834009)

摘　　要：Two ultrasonic methods were studied for determining the parameters of a composite consisting of a soft thin film attached beneath a hard plate substrate from resonant frequencies and amplitude spectra in low frequency region,respectively.Analyses of the sensitivity function, the objective function and the error transfer function were presented for discussing the effects of the two methods for both single parameter and two-parameter inversion.Two techniques were employed in experiment to characterize a composite consisting of a film attached beneath an aluminum plate substrate with a 7 MHz center frequency broadband transducer.It was observed that the results were similar for single parameter inversion and the method based on resonant frequencies got better result for two-parameter inversion under the same condition. The relative errors of the method based on resonant frequencies for inversing acoustic impedance and time-of-flight were 3.4%and 4.7%,respectively,and the method based on amplitude spectra got no results.Two ultrasonic methods were studied for determining the parameters of a composite consisting of a soft thin film attached beneath a hard plate substrate from resonant frequencies and amplitude spectra in low frequency region,respectively.Analyses of the sensitivity function, the objective function and the error transfer function were presented for discussing the effects of the two methods for both single parameter and two-parameter inversion.Two techniques were employed in experiment to characterize a composite consisting of a film attached beneath an aluminum plate substrate with a 7 MHz center frequency broadband transducer.It was observed that the results were similar for single parameter inversion and the method based on resonant frequencies got better result for two-parameter inversion under the same condition. The relative errors of the method based on resonant frequencies for inversing acoustic impedance and time-of-flight were 3.4%and 4.7%,respectively,and the method based on amplitude spectra got no results.

分 类 号：O484.1[理学—固体物理] TQ639[理学—物理]