An inverse procedure for crack detection using integral strain measured by optical fibers

We present an inverse procedure for the detection of a three-dimensional crack in plates and shells using a genetic searching algorithm. The integral strain, which can be measured by optical fibers, is utilized as the input for the inverse procedure. Two parameters, each with three components, are used to describe the location and size of the crack. A shell element model is created with a re-mesh operation in the numerical simulation of the integral strains. The squared difference of the integral strains obtained from a plate with an actual crack and from a plate with a trial crack is defined as the objective function. The best crack parameters are found by minimizing the objective function using a searching technique of the micro genetic algorithm (μGA). We have presented numerical examples to demonstrate the procedures and effectiveness of the method.