Novel method for true guided waves spectral characteristics estimation using a logistic function fit and nonlinear least square algorithm

The paper presents a method for the estimation of true spectral characteristics and for the analysis of numerical models for guided waves. The proposed procedure makes use of a four parametric logistic distribution, called logistic function, and nonlinear least square fit algorithm. The method requires numerical results obtained for five various discretizations only in order to properly estimate true spectral characteristics. Thereby, the method can be used for any arbitrarily sets of data. A general framework for the proposed analysis is given, along with application examples. Although the proposed method is verified and application examples are given based on the local interaction simulation approach for elastic waves propagation, the proposed methodology can easily be adopted for other numerical methods, for example, finite elements.