The identification of cracks using boundary elements and evolutionary algorithms

This paper is devoted to the identification problems for structures which contain cracks. The problem of crack identification is formulated as the minimization of the difference between the measured and computed values of displacements or stresses at selected boundary nodes. The coupling of the dual boundary element method and evolutionary algorithms is proposed to solve the problem. The identification of single cracks of different shapes is presented. The multiple crack identification is also considered. The problem of the identification of unknown number of cracks is formulated by introducing a special kind of chromosome. The influence of random errors in experimentally measured displacements on a convergence of the evolutionary identification is examined. A hybrid evolutionary approach based on sensitivity information of the fitness: function is tested. Several numerical examples are presented. (C) 2001 Elsevier Science Ltd. All rights reserved.