Thin-Walled Struct. 26, 261-286, 1996
X. Wang and F.G. Rammerstorfer
Institute of Lightweight Structures and Aerospace
TU Wien, Vienna, Austria
A finite strip (FS) method is presented for the numerical investigation of
two design parameters - effective breadth and effective width - of stiffened
For the effective breadth, stiffened plates under bending are studied.
Due to the transverse bending loads there is shear transmission through the
plate form the stiffener which leads to a non-uniform longitudinal stress
distribution across the plate width.
This phenomenon, termed as shear lag, can be represented by the 'effective
breadth concept', and has been extensively studied by analytical methods.
A linear FS method is presented which utilizes the advantages of decoupling
of Fourier terms on the one hand and, on the other hand, allows the treatment
of both webs and flanges using a plate model.
A definitely different situation exists for estimating the effectiveness
of the breadth (or width) of plates in the postbuckling range.
The 'concept of effective width' is based on the fact that plates with
supported longitudinal edges and/or stiffeners can accept additional load
after buckling under longitudinal compression, and enables the designer
to evaluate the postbuckling strength of plate structures simply by using the
design parameter 'effective width'.
Several formulae (most of them empirically derived) exist for an approximative
calculation of the load dependent value of the effective width.
A nonlinear FS method is developed and applied to the investigation of
the postcritical strength of locally buckled structures.
An incremental successive iterative procedure is introduced for an effective