STACKING-SEQUENCE OPTIMIZATION BY A GENETIC ALGORITHM WITH A NEW RECESSIVE GENE LIKE REPAIR STRATEGY

A genetic algorithm is used to obtain the stacking sequence of the lam inate that has the set of lamination parameters that are the closest t o a set of target lamination parameters. In addition, the laminate is required to be balanced and to have no more than 4 contiguous plies of the same orientation in order to satisfy practical considerations. Th is problem is a constrained combinatorial optimization problem which i s usually difficult to solve. The difficulty of enforcing constraints in genetic optimization is handled by introducing a new repair strateg y. The new repair strategy does not alter genes but only changes decod ing rules, and is similar in this respect to the way recessive genes o perate in biology. The relationship between the reliability of the gen etic algorithm and the probability of repair was investigated, and it is shown that 100% probability of repair is optimal when the target la minates include 45 degrees plies. Since practical composite laminates usually include 45 degrees plies, it is concluded that the repair stra tegy discussed herein should always be used with the optimization. (C) 1998 Elsevier Science Limited. All rightss reserved.