An optimised design of a dynamic umbilical requires an extreme cross-sectional stress to be maintained within an allowable limit and a fatigue life to be guaranteed to be sufficient. It should be noted that a dynamic umbilical is a typical geometric bi-scale structural system. It consists of a local cross-sectional scale and a global configuration scale, which are significantly different in terms of geometric sizes. In this study, we established an approximate model to achieve an optimised design of the dynamic umbilical by considering the parameters of local cross-sections and global configurations simultaneously. The design variables of a dynamic umbilical are independently identified and defined at both local sectional and global configuration scales in the approximate model. Furthermore, we selected the maximum tension strain and the maximum bending moment, for covering local and global properties, as the objectives to be minimised. The approximate model was observed to be effective in integrating the local and global responses into one loop so that the computational efficiency could be significantly increased. We implemented the optimisation framework on a dynamic umbilical with a lazy-wave configuration, which is considered to be a basis for a case study. Furthermore, we verified the feasibility and effectiveness of the integrated optimisation strategy by numerical simulations. Moreover, we compared the optimised dynamic umbilical properties with those without optimisation. It was observed that the fatigue life of the optimised dynamic umbilical was improved significantly, thereby indicating that the integrated optimisation methodology provides a new model and algorithm for an efficient design of the dynamic umbilical.

动态脐带的优化设计要求极限横截面应力保持在允许的范围内，并且疲劳寿命要保证足够。应该注意的是，动态脐带是典型的几何双尺度结构系统。它由局部横截面比例尺和整体配置比例尺组成，它们在几何尺寸方面存在显着差异。在这项研究中，我们建立了一个近似模型，通过同时考虑局部横截面和全局配置的参数来实现动态脐带的优化设计。动态脐带的设计变量在近似模型中以局部截面和整体配置比例独立标识和定义。此外，我们选择了最大的拉伸应变和最大的弯矩来覆盖局部和全局特性，以此作为最小化的目标。观察到近似模型可以有效地将局部和全局响应集成到一个循环中，从而可以显着提高计算效率。我们在具有延迟波配置的动态脐带缆上实现了优化框架，这被认为是案例研究的基础。此外，我们通过数值模拟验证了集成优化策略的可行性和有效性。此外，我们将优化的动态脐带性质与未优化的脐带性质进行了比较。观察到，优化的动态脐带的疲劳寿命显着提高，