RIASSUNTO
Abstract
Generally the multidisciplinary design optimization in ship design only considers the impact of certainties with ignoring the existence of uncertainties in the design. The results of the optimization obviously cannot really guarantee the feasibility of ship hull and excellence of sailing performance. Currently, uncertainty multidisciplinary design optimization of ship focuses on one dimension of uncertainty analysis. To obtain the optimal solution of ship design, the problem of Multidisciplinary Robust Design Optimization (MRDO) under multi-dimensional uncertainties is studied in the paper by analyzing and considering uniform distribution and normal distribution of random uncertainties. It deduces a new multi-dimensional polynomial chaos approach based on Legendre polynomials and Hermite polynomials. It is established the mathematical models of multi-dimensional uncertainty quantification while considering the speed reducer and bulk carrier optimization as the research objects. By analyzing the influence of multi-dimensional stochastic uncertainties to the ship design optimization, the research of ship robust multidisciplinary design optimization is completed. The possibility of failure in ship design optimization is effectively reduced and avoided.
Introduction
Over the years, optimization has been playing an increasingly important role in engineering. Complex systems like ships and other marine structures must fulfill multiple, often conflicting objectives (Knight Joshua T., 2014). Multidisciplinary Design Optimization (MDO) can be used to evaluate multiple, conflicting objectives simultaneously and reveal useful tradeoff information for decision-making purposes (Dong Suzhen,2014). However, real world applications are affected by uncertainty and require uncertainty analysis and uncertainty quantification (UQ). Uncertainty exists in many of the design variables and system parameters for ship and marine structure design. This is especially true in the early stages of design. For this reason and others, optimization of a ship's performance characteristics is often delayed until later in the design process, after uncertainties have been at least partially resolved.