Elastic-plastic wrinkling of compression loaded sandwich panels made with layered cores was studied analytically and experimentally. A core with a stiff layer near the sandwich skins can improve various properties, including wrinkling and impact strengths, with only a minor weight penalty. The 2D plane stress and plane strain bifurcation problems were solved analytically, save for a determinantal equation which was solved numerically. Experiments were performed on aluminum skin/foam core sandwich panels with different combinations of stiff and soft core materials. Good correlation between experiments and theory was obtained.

Keywords:
aluminium, polymer foams, bifurcation, yield stress, elastoplasticity, impact strength, elastic constants
Topics:
Aluminum, Bifurcation, Plane strain, Stress, Skin, Impact strength
1.
Danielsson
,
M.
, and
Grenestedt
,
J. L.
,
1998
, “
Gradient Foam Core Materials for Sandwich Structures, Preparation and Characterisation
,”
Composites, Part A
,
29
(
8
), pp.
981
–
988
.
2.
Gough
,
G. S.
,
Elam
,
C. F.
, and
de Bruyne
,
N. A.
,
1940
, “
The Stabilization of a Thin Sheet by a Continuous Supporting Medium
,”
J. R. Aeronaut. Soc.
,
44
, pp.
12
–
43
.
3.
Hoff
,
N. J.
, and
Mautner
,
S. E.
,
1945
, “
The Buckling of Sandwich-Type Panels
,”
J. Aeronaut. Sci.
,
12
, pp.
285
–
297
, eq. (103).
4.
Grenestedt, J. L., and Olsson, K.-A., 1995, “Wrinkling of Sandwich with Layered Core or Non-Symmetric Skins,” Proc. Third International Conference on Sandwich Construction, Southampton, UK, 12–15 September.
1.
Shield
,
T. W.
,
Kim
,
K. S.
, and
Shield
,
R. T.
,
1994
, “
The Buckling of an Elastic Layer Bonded to an Elastic Substrate in Plane Strain
,”
ASME J. Appl. Mech.
,
61
, pp.
231
–
235
.
2.
Corrections: ASME J. Appl. Mech., 61, pp. 796, and further, 1994, b=ω[1−P1−2ν/2μ1−ν]1/2 in Eq. (4).
1.
Hill
,
R.
,
1957
, “
On Uniqueness and Stability in the Theory of Finite Elastic Strains
,”
J. Mech. Phys. Solids
,
5
, pp.
229
–
241
.
2.
Hill
,
R.
,
1967
, “
Eigenmodal Deformations in Elastic/Plastic Continua
,”
J. Mech. Phys. Solids
,
15
, pp.
371
–
386
.
3.
Hutchinson, J. W., 1974, “Plastic Buckling,” in Advances in Applied Mechanics, C.-S. Yih, ed., 14, pp. 67–144.
4.
DIAB. Divinycell H-Grade Technical Manual, 10.00. DIAB AB, Box 201, S-312 22 Laholm, Sweden (also available at www.diabgroup.com/DIAB/filecabinet.nsf/LookupFiles/H_Man_M/$file/H_Man_M.pdf)
5.
Ley, R. P., Lin, W., and Mbanefo, U., 1999, “Facesheet Wrinkling in Sandwich Structures,” NASA/CR-1999-208994.
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