Optimization of Mechanically Coupled Composite Pipes by Genetic Algorithms

The optimization of composite components with regard to minimum weight and maximum load bearing capacity in consideration of multiple constraints is an optimization problem of rather high complexity. Genetic Algorithms are a good choice for solving such problems. In this paper the formulation of a Genetic Algorithm for the simultaneous optimization of two thin walled, mechanically coupled composite pipes subjected to a combination of thermal and mechanical loads is presented. The optimization goal is the minimization of the total mass of the pipe arrangement taking into account multiple design constraints. It is shown that Genetic Algorithms are valueable tools for solving optimization problems with a large number of parameters. Furthermore, it is possible to find additional, perhaps practicable, close-to-optimal configurations as a byproduct of the optimization process. Laminated composites provide unique opportunities with regard to tailoring thermo-mechanical properties by selecting the right orientations and thicknesses of each ply. Thus, laminated composites offer lots of opportunities for the application of advanced optimization methods. Several parameters and constraints are needed to describe the desired optimal configuration. In terms of optimization this means that an extremum in a constrained multidimensional search space has to be found. Genetic Algorithms are a good choice for solving such problems. They are based on the mechanisms of natural selection and genetics and seek the optimal solution(s) through a guided random search. In this paper the formulation of a Genetic Algorithm for the simultaneous optimization of two thin walled, mechanically coupled composite pipes subjected to a combination of thermal and mechanical loads is presented. The optimization goal is the minimization of the total mass of the pipe arrangement in consideration of multiple design constraints. These constraints are the requirements for symmetric and balanced stackings of the laminates, the requirement of not having more than four consecutive plies with equal orientations, and the limitation of using discrete orientation and thickness values for the plies.