Comput.Model.Engng.Sci. 12, 229-241, 2006
D.H. Pahr and F.G. Rammerstorfer
Institute of Lightweight Design and Structural
TU Wien, Vienna, Austria
Sandwich structures are efficient lightweight materials.
Due to their design they exhibit very special failure modes such as global
buckling, shear crimping, facesheet wrinkling, facesheet dimpling,
and face/core yielding.
The core of the sandwich is usually made of foams or cellular materials, e.g.,
Especially in the case of honeycomb cores the correlation between analytical
buckling predictions and experiments may be poor (Ley, Lin and Uy (1999)).
The reason for this lies in the fact that analytical formulae typically assume
a homogeneous core (continuous support of the facesheets).
This work highlights problems of honeycomb core sandwiches in a parameter
regime, where the transition between continuous and discrete support of the
facesheets is studied.
Periodic finite element unit cell models are utilized for this task, which
offer the big advantage of a homogeneous load introduction to the structure.
The finite element models are found to be well suited for all kinds of
Different uni- and bi-axial loadings are considered as well as influences of
core height, core material, core geometry, and facesheet thickness are
Finally, a new analytical approach is introduced for the unexpected core cell
wall buckling under in-plane compression of the sandwich, which predicts the
critical load very accurately.