The single perturbation load approach applied to imperfection sensitive conical composite structures

Journal article (2014)

Authors

Regina Khakimova Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)
Christopher J. Warren University of New South Wales
Rolf Zimmermann Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)
Saullo G.P. Castro Private University of Applied Sciences
Mariano A. Arbelo Private University of Applied Sciences
Richard Degenhardt Private University of Applied Sciences, Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)
Research Group
Aerospace Structures & Computational Mechanics (Aerospace Engineering) (TU Delft)
Design Buckling Composite Imperfections Knock-down factor Truncated conical shell
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Published Date

01-01-2014

Language

English

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Faculty

Aerospace Engineering

Department

Aerospace Structures & Materials

Research Group

Aerospace Structures & Computational Mechanics

Abstract

The importance of taking into account geometric imperfections for cylindrical and conical thin-walled structures prone to buckling had been already recognized by the first authors dealing with new formulations. Nowadays, the analysts still use empirically based lower-bound methods such as the NASA SP-8007 guideline to calculate the required knock-down factors (KDFs), which does include important mechanical properties of laminated composite materials, such as the stacking sequence. New design approaches that allow taking full advantage of composite materials are required. The single perturbation load approach (SPLA), a new deterministic approach first proposed by Hühne, will be investigated with unstiffened composite conical structures varying the geometry, lamina and layup. The SPLA's capability for predicting KDF is compared with the NASA approach. The SPLA was applied to the geometrically perfect structures and to the structure with geometric imperfections of two types, mid-surface imperfections and thickness imperfections. The study contributes to the European Union (EU) project DESICOS, whose aim is to develop less conservative design guidelines for imperfection sensitive thin-walled structures.