Genetic algorithm in structural damage detection

Detection of structural damage is an inverse problem in structural engineering. There are three main questions in the damage detection: the existence, location and extent of the damage. In this study, the problem is formulated as an optimization problem, which is then solved by using genetic algorithm (GA). Static measurements of displacements at few degrees of freedom (DOFs) are used to identify the changes of the characteristic properties of structural members such as Youngʹs modulus and cross-sectional area, which are indicated by the difference of measured and computed responses. In order to avoid structural analyses in fitness evaluation, the displacements at unmeasured DOFs are also determined by GA. Unlike the traditional mathematical methods, which guide the direction of hill climbing by the derivatives of objective functions, GA searches the problem domain by the objective function itself at multiple points. The proposed method is able to detect the approximate location of the damage, even when practical considerations limit the number of on-site measurements to only a few.