Multidisciplinary design optimization of non-uniform stiffened cylindrical shells

Abstract

ObjectivesUnderwater structures have strict requirements for intensity, mass, vibration, noise and so on. From a multidisciplinary perspective, realizing the design optimization of such structures to improve their overall performance is of great significance.MethodsThe enhanced analytical target cascading method and surrogate model are employed for the design optimization of underwater structure vibration and acoustic radiation: an enhanced target cascading (ATC) method based on the Lagrange duality theory and traditional ATC method is established to achieve the classification of problems and parallel optimization of the performance of different disciplines; and the Kriging surrogate model is used to solve the time-consuming problem in the calculation of the vibration and acoustic radiation of underwater structures. Underwater non-uniform stiffened cylindrical shells (i.e., underwater unmanned vehicles) are selected for multidisciplinary design optimization (MDO): six design variables are selected, and the structural mass, stress components, resonant frequency and corresponding radiated power level are regarded as objectives for establishing the parallel optimization model when considering the vibration and acoustic radiation characteristics and lightweight requirements.ResultsThe results show that the Kriging surrogate model can accurately predict the response in the design space, while the enhanced ATC method can obtain effective multidisciplinary optimization results with a 30% increase in convergence properties.ConclusionsThis study shows that multidisciplinary design optimization based on the enhanced ATC method and surrogate model not only obtains effective results but also has better convergence properties.

Keywords

• non-uniform stiffened cylindrical shell
• enhanced analytical target cascading method
• surrogate model
• multidisciplinary design optimization