表面波测定涂层材料参数的反演方法

基于涂层结构中表面波的频散方程,提出了一种从实测的相速度频散数据计算材料参数的反演方法.通过引入以涂层参数、表面波相速度和频率作变量的目标函数,将实测的相速度频散数据代入目标函数,使其取最小值,从而反向计算出涂层的材料参数.为了解决单模态频散数据反演时的多值性问题,数值算例分别分析了采用表面波频散的二阶模态和三阶模态数据,同时反演3个材料参数(涂层密度、纵波速度和横波速度)的过程,验证了多模态反演方法的可行性.值得指出,该反演方法适用于任意多阶模态频散数据.

An Inversion Method for the Determination of Coating Properties by Surface Waves

Based on the dispersive equation of surface waves in the coated materials,an inverse method was proposed for calculating the coating properties from the measured dispersive data of phase velocities.By introducing an objective function dependent on the coating material parameters,the phase velocities and frequencies of surface waves,the material parameters of coating layers can be inversed from the measured velocity dispersion to minimize it.In the numerical analyses,two inversion cases were investigated respectively to avoid the multivalued problem existing in the single mode inversion,using two modes and three modes of phase velocity dispersion,where the three parameters(the density,longitudinal and transverse velocities) can be simultaneously worked out.The numerical results show the inversion with multiple modes is valid.Moreover,the proposed method can be applied to arbitrary multiple modes.