Lavrentyev A I, Rokhlin S I
Department of Industrial Welding and Systems, The Ohio State University, Columbus 43210, USA.
Ultrasonics. 2001 Apr;39(3):211-21. doi: 10.1016/s0041-624x(00)00066-4.
An ultrasonic method proposed by us for determination of the complete set of acoustical and geometrical properties of a thin isotropic layer between semispaces (J. Acoust. Soc. Am. 102 (1997) 3467) is extended to determination of the properties of a coating on a thin plate. The method allows simultaneous determination of the coating thickness, density, elastic moduli and attenuation (longitudinal and shear) from normal and oblique incidence reflection (transmission) frequency spectra. Reflection (transmission) from the coated plate is represented as a function of six nondimensional parameters of the coating which are determined from two experimentally measured spectra: one at normal and one at oblique incidence. The introduction of the set of nondimensional parameters allows one to transform the reconstruction process from one search in a six-dimensional space to two searches in three-dimensional spaces (one search for normal incidence and one for oblique). Thickness, density, and longitudinal and shear elastic moduli of the coating are calculated from the nondimensional parameters determined. The sensitivity of the method to individual properties and its stability against experimental noise are studied and the inversion algorithm is accordingly optimized. An example of the method and experimental measurement for comparison is given for a polypropylene coating on a steel foil.
我们提出的一种用于确定半空间之间薄各向同性层的声学和几何特性全套参数的超声方法（《美国声学学会杂志》102 (1997) 3467）被扩展用于确定薄板上涂层的特性。该方法可从垂直和斜入射反射（透射）频谱中同时确定涂层厚度、密度、弹性模量和衰减（纵向和剪切）。涂层板的反射（透射）表示为涂层六个无量纲参数的函数，这些参数由两个实验测量频谱确定：一个是垂直入射频谱，另一个是斜入射频谱。引入这组无量纲参数使得重构过程从在六维空间中的一次搜索转变为在三维空间中的两次搜索（一次垂直入射搜索和一次斜入射搜索）。根据所确定的无量纲参数计算涂层的厚度、密度以及纵向和剪切弹性模量。研究了该方法对各个特性的灵敏度及其对实验噪声的稳定性，并相应地优化了反演算法。给出了该方法及用于比较的实验测量的一个示例，对象是钢箔上的聚丙烯涂层。
