In contrast to the familiar Kirchoff approach, a simple, consistent, s
hear flexible model for the stability analysis of stiffened panels has
been developed in the context of hybrid mixed technique. This model i
s composed of a quadrilateral plate element, as well as its complement
ary skeletal grid element. The formulation is based on the Hellinger/R
eissner mixed variational principle with independently assumed displac
ement and strain fields. The proposed model has been utilized to devel
op a general finite element code for determination of critical bucklin
g stresses of stiffened panels for any case of in-plane loadings and b
oundary conditions. The effectiveness and practical usefulness of this
model have been demonstrated by a variety of numerical results for pr
actical applications. In particular, design curves for buckling stress
es of simply supported rectangular panels with central cut-outs and la
teral stiffeners have been developed under in-plane load-type. These c
urves provide a valuable insight into the behavior of stiffened panels
and could be useful for design codes.