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Analytical buckling analysis of composite structures

Aircraft and Aircraft SystemsMaterialsEco-Efficiency

Development of highly efficient analysis methods describing the buckling and post-buckling behaviour of stiffened and unstiffened thin-walled composite structures under in-plane loads.

In many fields of lightweight design the use of structures consisting of composite materials is increasing steadily. When building a mechanical model of the real structure, e.g. a ship's hull or an aircraft's fuselage, the entire structure is often decomposed into substructures which can then be idealized using rods, beams, plates or shells.

In the framework of a cooperative doctoral dissertation, various analysis methods are being developed describing the linear and non-linear buckling behaviour of stiffened and unstiffened thin-walled structures.

The investigations include (but are not limited to) the linear and non-linear buckling behaviour of the following structural configurations:

  • A slightly curved, orthotropic cylindrical shell with all edges simply supported under longitudinal compression.
  • An anisotropic plate strip with elastically clamped long edges under biaxial compression and shear.
  • An orthotropic plate with one long edge elastically clamped and the other one free under compression.
  • An anisotropic plate strip, stiffened with T-profiles, considering periodic boundary conditions at the long edges under axial compression and shear.

The main objective in developing the analysis methods is high computational efficiency. Thus, variation methods in combination with shape functions with few degrees of freedom are applied to solve stability problems.

By inserting shape functions into the compatibility condition of in-plane strains, closed-form analytical solutions of the Airy stress functions are obtained.  The equilibrium conditions are then used to deduce the load-displacement relationships by means of the Galerkin method. All remaining characteristics, such as in-plane displacements and stresses, are derived from kinematics and material law.

Contact

Prof. Dr.-Ing. Michael Seibel, michael.seibel@haw-hamburg.de, +49 [0]40-42875-7988

Dipl.-Ing. (FH) Matthias Beerhorst, matthias.beerhorst@haw-hamburg.de

Leadership

Hamburg University of Applied Sciences, Department of Automotive and Aeronautical Engineering

Partner

Technical University of Berlin