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From:
Victor M. Casado (1), Svend Hinsch (1), Jesús Gómez García (1), and Saullo G. P. Castro (2)
(1) Airbus Defence & Space, Bremen, Germany
(2) PFH Göttingen, Composite Engineering Campus, Stade, Germany
(2) EMBRAER, Brazilian Aerospace Company, Brazil
“Lower-bound methods to predict the buckling load of cylindrical sandwich shell under axial compression”, DESICOS (www.DESICOS.eu), 2014 or 2015. [3rd Int. Conf. on Buckling and Postbuckling Behaviour of Composite Laminated Shell Structures with DESICOS Workshop (25. - 27.03.2015)]
ABSTRACT: A numerical investigation was carried out to assess the impact of geometrical imperfections on the stability of laminated sandwich cylindrical shells. This paper summarizes the most interesting results of a more extensive investigation in which a number of geometrical imperfection patterns were implemented. Specifically, eigenmode-shaped and single perturbation load imperfections are discussed herein. Such imperfections might provide a method for fast prediction of lower-bound buckling loads during the design phase, when details about the real structural and material defects are unknown. In order to make design and qualification more affordable, it is common practice to use sub-scaled hardware for testing. As part of the DESICOS project, a sandwich cylinder product of the sub-scaling of a typical launcher Inter Skirt Structure (ISS) will be tested. This paper verifies the sub-scaling method, validates the test set-up and makes a prediction of the test results. Buckling mechanisms are described and the different lower-bound methods are discussed.
The authors of the paper write:
"Deterministic approaches like the Single Perturbation Load Approach (SPLA) have recently gained importance [9]. This method considers a perturbation load applied normally to the shell surface as a disturbance that produces a worst case imperfection which can directly lead to a realistic and conservative design load.
[9] Hühne C., Rolfes R., Breitbach E., Tessmer J., Robust design of composite cylindrical shells under axial compression - simulation and validation. Thin-walled structures, vol. 46, no. 7, p. 947-962, 2008
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