Localized and cellular buckling in stiffened plates
File(s)
Author(s)
Farsi, Maryam
Type
Thesis or dissertation
Abstract
Nonlinear buckling behaviour of a thin-walled simply-supported stiffened panel that
has uniformly spaced longitudinal stiffeners is studied. The structure is made from
a linear elastic, isotropic and homogeneous material. The panel is subjected to pure
compression applied at the centroid of whole cross-section. In such structures, the
nonlinear interaction can occur between a global (Euler) buckling and local plate ( i.e.
the stiffener or the main plate) buckling modes. The interactive buckling behaviour
is usually more unstable than when the modes are triggered individually. This can
lead to a significant reduction of the load-carrying capacity. The current work focuses
on the case where the stiffening is only on one side of the main plate.
An analytical model of a perfect thin-walled stiffened plate is formulated based on
variational principles by minimizing the total potential energy. The equations of equilibrium
are then solved numerically using the continuation and bifurcation software
Auto to determine the post-buckling behaviour. Cellular buckling (or snaking) is
revealed analytically in such a component arising from nonlinear local global interactive
buckling, perhaps for the first time. In addition, the effect of varying the rigidity
at the main plate -stiffener junction is studied; a rapid erosion of the cellular buckling
response is revealed by increasing the joint rigidity.
The initial model is then developed by including more degrees of freedom within the
stiffened panel and the introduction of global and local imperfections. The results from the analytical model are validated by the finite element (FE) method using the
commercial software Abaqus as well as by comparing against some experimental
results taken from the literature.
To obtain a greater understanding of the drivers of the structural behaviour, parametric
studies are conducted for a variety of different plate and stiffener geometries
as well as an investigation into the heightened sensitivity to geometric imperfections.
The worst forms of local imperfection are identified in terms of the initial amplitude,
number of waves and the degree of localization. The imperfection sensitivity
and the parametric studies are conducted for two limiting cases, where the main
plate- stiffener joint is assumed to be fully pinned or fully rigid. A framework for
establishing the zone where structural designers need to consider mode interaction
carefully is presented.
has uniformly spaced longitudinal stiffeners is studied. The structure is made from
a linear elastic, isotropic and homogeneous material. The panel is subjected to pure
compression applied at the centroid of whole cross-section. In such structures, the
nonlinear interaction can occur between a global (Euler) buckling and local plate ( i.e.
the stiffener or the main plate) buckling modes. The interactive buckling behaviour
is usually more unstable than when the modes are triggered individually. This can
lead to a significant reduction of the load-carrying capacity. The current work focuses
on the case where the stiffening is only on one side of the main plate.
An analytical model of a perfect thin-walled stiffened plate is formulated based on
variational principles by minimizing the total potential energy. The equations of equilibrium
are then solved numerically using the continuation and bifurcation software
Auto to determine the post-buckling behaviour. Cellular buckling (or snaking) is
revealed analytically in such a component arising from nonlinear local global interactive
buckling, perhaps for the first time. In addition, the effect of varying the rigidity
at the main plate -stiffener junction is studied; a rapid erosion of the cellular buckling
response is revealed by increasing the joint rigidity.
The initial model is then developed by including more degrees of freedom within the
stiffened panel and the introduction of global and local imperfections. The results from the analytical model are validated by the finite element (FE) method using the
commercial software Abaqus as well as by comparing against some experimental
results taken from the literature.
To obtain a greater understanding of the drivers of the structural behaviour, parametric
studies are conducted for a variety of different plate and stiffener geometries
as well as an investigation into the heightened sensitivity to geometric imperfections.
The worst forms of local imperfection are identified in terms of the initial amplitude,
number of waves and the degree of localization. The imperfection sensitivity
and the parametric studies are conducted for two limiting cases, where the main
plate- stiffener joint is assumed to be fully pinned or fully rigid. A framework for
establishing the zone where structural designers need to consider mode interaction
carefully is presented.
Version
Open Access
Date Issued
2014-06
Online Publication Date
2015-05-31T06:00:13Z
2015-07-10T14:57:35Z
Date Awarded
2014-12
Advisor
Wadee, Ahmer
Publisher Department
Civil and Environmental Engineering
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)