Numerical and experimental study on comprehensive optimization for the KPIs of ship propulsion shafting design based on MDO

Abstract Ship propulsion shafting as an important part of the main power plant, its design quality affects the safety, stability and sustainability of ship operation directly, and it includes many components, which subjects to complex external loads during operation. Its design process is a complicated system design problem, which involves structure science, statics, rotor dynamics and other disciplines. To improve the quality and efficiency of shafting design, the Multi-disciplinary Design Optimization (MDO) strategy was adopted to achieve the optimal design in this paper. Further, the multi-objective optimization framework was established by analyzing the characteristics of the shafting design. The optimization strategy was employed to write the optimization algorithm and multidisciplinary design optimization scheme was obtained. In order to demonstrate the feasibility of this proposed method, a shafting testing platform (STP) was taken as an example, the vertical displacements of its two bearings were determined as design variables, and its key preference indexes (KPIs) comprehensive optimization objective function was acquired due to its practice states. Then, the MDO framework of the STP was constructed. The design variables were optimized by application of multi-objective Genetic Algorithm (MOGA), and the feasibility of this design idea was verified by several designed experiments.