Global optimization in FEM updating by coupled local minimizers

Coupled Local Minimizers (CLM) is a new method applicable to global optimization problems. With the CLM method a cooperative search mechanism is set up using a population of local optimizers, each starting from a different point in the search space. The individual local optimizers are coupled during the search process by interaction and information exchange. The combination of a fast convergence, due to the derivative information used in the local algorithms, with the expected capability of finding the global minimum, resulting from the parallel strategy, offers an efficient global optimization algorithm. The principal idea of CLM is worked out in the paper and illustrated on a test function. Next, CLM is used for Finite Element Model (FEM) Updating using experimental modal data. As an example the damage pattern is identified of a reinforced concrete beam, on which a modal test has been carried out before and after it was damaged.