Performance Evaluation of Augmented Lagrangian Coordination for MDO

The numerical performance and formulation flexibility of an augmented Lagrangian coordination method proposed by the authors is demonstrated on two example problems. First, a geometric programming problem is decomposed in a number of different ways to illustrate the flexibility of the approach in setting up different coordination structures. For this problem and a business jet design example, numerical results indicate that the coordination method is effective and robust in finding (local) solutions of the original non-decomposed problem, and does not introduce new local minima. The required coordination costs are found to be determined by how the problem is partitioned and coordinated. These costs do not only depend on the number of quantities that have to be coordinated, but also on their coupling strengths. The formulation flexibility of the method provides means to minimize these costs by adapting the decomposition to a problem at hand.