Efficient and Robust Shell Design of Space Launcher Vehicle Structures

Friedrich, L., Ruess, M. and Schröder, K.-U. (2016) Efficient and Robust Shell Design of Space Launcher Vehicle Structures. In: 57th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference (SciTech2016), San Diego, CA, USA, 4-8 Jan 2016, ISBN 9781624103926 (doi: 10.2514/6.2016-1973)

Abstract

Space launcher vehicles consist of thin-walled shell structures which are prone to buckling and often are sensitive towards geometrical imperfections. Even small deviations of the shell from the perfect structure which still are within manufacturing tolerances, result in a tremendous decrease of load carrying capacity. To account for geometrical imperfections in an early design phase, empirical knock-down factors or theoretical approaches can be applied. In this paper, it is shown that the design of imperfection sensitive shell structures with unknown geometric imperfections may not lead to robust designs for the existing empirical and theoretical design methods. In contrast to unstiffened structures and grid stiffened shell structures, which are imperfection sensitive, it is known that the influence of imperfections during an early design phase of ring frame stringer stiffened shells is negligible when the post-buckling regime of the skin fields is exploited. Frame stringer stiffened structures can be designed in a robust manner, using efficient analysis methods, as imperfection tolerant structures; but, existing methods to size ring frame stiffeners of space launcher vehicles shell structures do not mandatorily lead to reliable and light designs. In this contribution a novel method for the efficient design of ring frame stringer stiffened shells is presented. The suggested approach is based on the explicit description of the mechanical behavior of the ring frame stiffeners at the onset of panel instability. Together with existing sizing methods for stringer stiffened shell panels the suggested approach allows for robust designs of ring frame stringer stiffened shells. The application of the novel method to size ring frames reveals that the minimum stiffness requirements are satisfied likewise with regard to existing methods; whereby, the lightweight potential is not mandatorily exploited using existing methods.

• Item Type: Conference Proceedings
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Ruess, Dr Martin
• Authors: Friedrich, L., Ruess, M., and Schröder, K.-U.
• College/School: College of Science and Engineering > School of Engineering > Infrastructure and Environment
• ISBN: 9781624103926