Environmental factors such as temperature and humidity influence the efficacy of defect imaging procedures based on the identification of changes between an intact state and the current state of a sample/component/structure in the presence of a defect. In this paper, we focus on the Reconstruction Algorithm for Probabilistic Inspection of Damage (RAPID) and propose a nonlinear Lamb wave version of RAPID to visualize a delamination in a composite structure without having to know anything about the intact state, i.e. a baseline free RAPID. Once the optimal frequency selection of Lamb waves in a pitch-catch configuration mode is performed, low and high excitation amplitude signal responses within a sparse array at that frequency are evaluated along each transducer-receiver path by analyzing a set of damage sensitive parameters: the correlation coefficient, the energy of the scaling subtracted signal, and the third harmonic ratio. Processing of this information leads to a corresponding probabilistic damage map of the area within the sparse array. The obtained results from a validation experiment demonstrate the capability of this nonlinear variant of RAPID for the identification of a delamination in a composite structure.
|Number of pages||11|
|Journal||Acta Acustica united with Acustica|
|Publication status||Published (in print/issue) - 1 Nov 2017|