A Hybrid Framework of Efficient Multi-Objective Optimization of Stiffened Shells with Imperfection

In the practical engineering applications of stiffened shell, the initial imperfection is inevitable and it could cause significant reduction in the load-carrying capacity of stiffened shell. The light-weight optimization of stiffened shell is generally performed under the constraint of fixed maximum load-carrying capacity. However, the load-carrying capacity of stiffened shell has been improved continuously as the promotion of manufacturing technology, which causes the previous strategies of light-weight optimization become conservative and outdated. Therefore, an improved hybrid framework of multi-objective optimization of stiffened shell with imperfection is necessary and presented in this paper, which focus on developing a general posterior design method to determine the optimal weight according to the different collapse loads. A new adaptive update criterion based on the Kriging model is developed to improve the efficiency and accuracy of the hybrid framework. The present optimal results provide a set of the Pareto optimal points and form a Pareto front, from which new posterior design can be achieved.

Definition and representation of stiffened shell structures in the context of an integrated development process

Purpose A novel development process aims at finding solutions for lightweight stiffened shell structures and their efficient production. To respect the strong interdependency of structural design and production planning, particularly observed for composite structures, it is of high interest to start considering production effects in early development phases. This integrated approach requires an integrated representation of structure and production. The purpose of this study is to investigate the scope of relevant data and to find a structure for its representation. Design/methodology/approach The development task is analyzed and a system of so-called solution dimensions is presented, which covers all important aspects of stiffened shell structures and their production. An integrated product data model is developed to cover all of the solution dimensions. Findings The product data model consists of five coherent partial models. It is explained how these models are defined and how they are connected to each other. An academic example of an aircraft fuselage panel is used to demonstrate the definition process. It is shown how even complex structural concepts are defined systematically. Practical implications It is explained how this integrated product data model is used in a software project for the development of aircraft fuselage structures. Originality/value The presented approach for the definition and representation of stiffened shell structures enables the developer, e.g. of aircraft fuselage, to respect the crucial criterion of manufacturability from early development phases on. Further, new design approaches, e.g. as inspired by topology optimization, can be considered.