Comparison of approximation methods for multidisciplinary design optimization of ship structures

As the complexity of ship structural designs keeps on increasing, the use of statistical techniques to build approximation models for expensive computer analysis is getting popular. In this paper, three commonly used approximation methods for multidisciplinary design optimization (MDO) of complex engineering systems, including response surface modeling, Kriging and radial basis function network, are reviewed briefly and compared through two case studies. The sample points are selected by a series of randomized orthogonal arrays. Error analysis is then performed to measure the accuracy of the approximation models. Besides the traditional quadratic response surface, fully three-order polynomial response surface models are also constructed for the comparison. It is found that Kriging model is much more suitable for MDO of ship structures than other models for its high accuracy and stability.