Detection of multiple cracks on a partially obstructed plate structure following the probabilistic approach

This paper addresses the problem of detecting multiple cracks on thin plates utilizing measured dynamic responses from only a few points on the target plate. Most existing model-based methods in the literature focus on the detection of single-crack or multi-crack with given crack number on beams. Only very limited number of researches have been carried out for the detection of multiple cracks for plate-type structures following the model-based method. There are two phase contained in the proposed crack detection methodology. The number of cracks is first identified by adopting the Bayesian model class selection method in the first stage. After that, the posterior (updated) probability density function (PDF) of the crack parameters, such as crack locations, lengths and depths are identified in the second phase following the Bayesian statistical identification framework. Very encouraging results are obtained for the case studies showing that the proposed methodology can correctly identify the number of cracks, the corresponding crack parameters and their associated uncertainties. Some useful discussions are also made through the case studies. © 2010 American Institute of Physics.