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Advances in Stability of Composite Airframe Structures Regarding Collapse, Robust Design and Dynamic Loading

Degenhardt, Richard (2008) Advances in Stability of Composite Airframe Structures Regarding Collapse, Robust Design and Dynamic Loading. ABAQUS Users-Meeting, 22.-23.Sept. 2008, Bad-Homburg, Germany.

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Abstract

European aircraft industry demands for reduced development and operating costs, by 20% and 50% in the short and long term, respectively. Structural weight reduction by exploitation of structural reserves in composite aerospace structures contributes to this aim, however, it requires accurate and experimentally validated stability analysis of real structures under realistic loading conditions. This paper presents new achievements from the area of computational and experimental stability research of composite aerospace structures which contribute to that field. The first two topics focus on stringer stiffened panels and the last one on imperfection sensitive unstiffened cylinders. Section 1 presents selected results achieved in the finished EU project COCOMAT, which deals with an accurate and reliable simulation of collapse. The main objective of COCOMAT is a future design scenario which exploits considerable reserves in fibre composite fuselage structures by accurate simulation of collapse. The project results comprise an experimental data base, improved slow and fast computational tools as well as design guidelines. In today’s design process dynamic loading, e.g. due to gusts or landing impact, is assumed to be uncritical, since the dynamic process increases buckling stability. Section 2 shows that rapidly applied loading of stiffened panels can yield critical dynamic behavior in the postbuckling regime. When applying the new design philosophy it has either to be assured that these critical interactions do not occur under the loading velocities to be expected, or they have to be taken into consideration. Section 3 presents a recently developed approach for unstiffened shells which are usually susceptible to imperfections. This robust design approach is based on a single buckle as the worst imperfection mode leading directly to the load carrying capacity of a cylinder. It also promises to improve the knock-down factors which are according the current guidelines very conservative. Future work should facilitate full applicability of the analysis methods in preliminary design. For that purpose speed of the collapse analysis of stiffened panels needs to be increased and for collapse simulation degradation must be taken into account. The application field of the robust design method should be widened towards imperfection sensitive stiffened shells (skin-dominant designs).

Item URL in elib:https://elib.dlr.de/83821/
Document Type:Conference or Workshop Item (Speech)
Title:Advances in Stability of Composite Airframe Structures Regarding Collapse, Robust Design and Dynamic Loading
Authors:
AuthorsInstitution or Email of AuthorsAuthors ORCID iD
Degenhardt, RichardUNSPECIFIEDUNSPECIFIED
Date:2008
Refereed publication:No
Open Access:Yes
Gold Open Access:No
In SCOPUS:No
In ISI Web of Science:No
Status:Published
Keywords:Composite Structures, Buckling, Stability, Postbuckling, Collapse, Imperfection, Dynamic Loading, Robust Design, Simulation tools, Experiments
Event Title:ABAQUS Users-Meeting
Event Location:Bad-Homburg, Germany
Event Type:national Conference
Event Dates:22.-23.Sept. 2008
Organizer:CAD-FEM
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Aircraft Research (old)
DLR - Research area:Aeronautics
DLR - Program:L AR - Aircraft Research
DLR - Research theme (Project):L - Simulation & Validation (old), L - Structures & Materials (old)
Location: Braunschweig
Institutes and Institutions:Institute of Composite Structures and Adaptive Systems > Structural Mechanics
Deposited By: Degenhardt, Richard
Deposited On:10 Dec 2013 19:19
Last Modified:31 Jul 2019 19:41

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