Analysis of mass and cost drivers of unstiffened isotropic shell structures considering their imperfection sensitivity

Abstract

The load carrying capacity of unstiffened thin-walled shell structures is highly sensitive to geometric imperfections. These imperfections are usually unknown during the preliminary design phase. The manufacturing process of these structures has a major influence on the geometric imperfections as well as on the manufacturing costs. The goal of this paper is to show the potential of a previously developed structural and economical design procedure and to analyse the cost and mass drivers of isotropic shell structures, considering their imperfection sensitivity. In order to do so, the available cost model is extended by a precise approach for calculating the material and scrap costs as well as by the assembly method TIG welding. Using an example structure, it is shown in detail how the used panel combination and the chosen assembly method have a significant impact on the structural mass and on the manufacturing costs. Additionally, it is shown that for a high manufacturing accuracy a high amount of panels is beneficial and vice versa. Furthermore, it is pointed out that it is possible to predict the buckling pattern based on the chosen panel combination.