• equivalent beam
• gfem
• nastran
• optimization
• stick model
• wing box

The most important objective of the current thesis research, carried out
at the Structures Numerical Analysis Department of Airbus UK, is the development
of three algorithms as well as computer programs for computing
the equivalent beam stiness distribution of a complex aircraft wing and for
generating the corresponding simplified beam finite element model, the stick
model.
The stick model is very suitable in the iterative process of wing optimization:
its basic function is to present accurate prediction of the real structure
deformation when it is subjected to similar load conditions and, being a very
simple model, it can be recalled thousands of times with very low computational
costs and time consuming.
After a brief review of the most common methodologies used in the industry
for generating the stick model, the algorithm of two of those methods and
that of a new one proposed as well as their implementation in an automated
program are detailed. It is provided an overview of the Thin Walled Beam
Theory and of the Global Finite Elements Models of wing structures; the
common modelling practices and the modelling elements of MSC Nastran
mostly used in a wing GFEM are described.
Furthermore, the thesis represents a user manual for large scale application
of the computer programs implemented: the steps required for the transition from a generic wing GFEM to the equivalent stick model, basing
on the discussed methodologies, are explained in details.
Finally, some representative examples of application are provided, as the
stick models of two different wing-box 3-D FEMs are generated using the
automated procedures implemented and their performance in similar load
conditions are compared with those of the GFEMs in terms of deformations.