The transverse shear stiffness of a newly-developed all-metal sandwich core structure is determined experimentally and numerically. The core structure is composed of a periodic array of domes which are introduced into an initially flat sheet through stamping. A finite element model of the stamping process is built and validated experimentally. A parametric study is performed to choose the stamping tool geometry such that the resulting core structure provides maximum shear stiffness for a given relative density. It is found that the optimal geometries for relative densities ranging from 0.2 to 0.35 all feature the same dome shape with the same height-to-width ratio. The simulation results also show that the estimated transverse shear strength of the proposed core structure is the same as that of hexagonal honeycombs of the same weight for high relative densities (greater than 0.35), but up to 30% smaller for low relative densities (lower than 0.2). In addition to numerical simulations of a representative unit cell, four-point bending experiments are performed on brazed prototype sandwich beams to validate the computational model.

References

1.
Bitzer
,
T.
,
1997
,
Honeycomb Technology
,
Chapman and Hall
,
London
.
2.
Ashby
,
M. F.
,
Evans
,
A. G.
,
Fleck
,
N. A.
,
Gibson
,
L. J.
,
Hutchinson
,
J. W.
, and
Wadley
,
H. N. G.
,
2000
,
Metal Foams: A Design Guide
,
Butterworth
,
Washington DC
.
3.
Wicks
,
N.
, and
Hutchinson
,
J. W.
,
2001
, “
Optimal Truss Plates
,”
Int. J. Solids Struct.
,
38
, pp.
5165
5183
.10.1016/S0020-7683(00)00315-2
4.
Gibson
,
L. J.
, and
Ashby
,
M. F.
,
1997
,
Cellular Solids, Structure and Properties
,
Cambridge University
,
Cambridge, MA
.
5.
Hale
,
J. R.
,
1970
, “
Anticlastic Cellular Core Structure Having Biaxial Rectilinear Truss Patterns
,”
US Patent No. 3,525,663.
6.
Zupan
,
M.
,
Chen
,
C.
, and
Fleck
,
N. A.
,
2003
, “
The Plastic Collapse and Energy Absorption Capacity of Egg-Box Panels
,”
Int. J. Mech. Sci.
,
45
, pp.
851
871
.10.1016/S0020-7403(03)00136-X
7.
Akisanya
,
A. R.
, and
Fleck
,
N. A.
,
2006
, “
Plastic Collapse for Thin-Walled Frusta and Egg-Box Material Under Shear and Normal Loading
,”
Int. J. Mech. Sci.
,
48
, pp.
799
808
.10.1016/j.ijmecsci.2006.01.020
8.
Tokura
,
S.
, and
Hagiwara
,
I.
,
2010
, “
A Study for The Influence of Work Hardening on Bending Stiffness of Truss Core Panel
,”
ASME J. Appl. Mech.
,
77
(
3
), pp.
1
6
.10.1115/1.4000419
9.
Mohr
,
D.
, and
Straza
,
G.
,
2005
, “
Development of Formable All-Metal Sandwich Sheets for Automotive Applications
,”
Adv. Eng. Mater.
,
7
(
4
), pp.
243
246
.10.1002/adem.200400216
10.
Jackson
,
K. R.
,
Allwood
,
J. M.
, and
Landert
,
M.
,
2008
, “
Incremental Forming of Sandwich Panels
,”
J. Mater. Process. Technol.
,
204
(
1
3
), pp.
290
303
.10.1016/j.jmatprotec.2007.11.117
11.
Pearce
,
R.
,
1991
,
Sheet Metal Forming
,
Hilger
,
London
.
12.
Seong
,
D. Y.
,
Jung
,
C. G.
,
Yang
,
D. Y.
,
Moon
,
K. J.
, and
Ahn
,
D. G.
,
2010
, “
Quasi-Isotropic Bending Responses of Metallic Sandwich Plates With Bi-Directionally Corrugated Cores
,”
Mater. Des.
,
31
(
6
), pp.
2804
2812
.10.1016/j.matdes.2010.01.009
13.
Gustafsson
,
R. N. G.
,
2000
, “
Ultralight Stainless Steel Sandwich Materials-HSSA
,”
Sandwich Construction
,
5
, pp.
169
176
.
14.
Markaki
,
A. E.
, and
Clyne
,
T. W.
,
2003
, “
Mechanics of Thin Ultra-Light Stainless Steel Sandwich Sheet Material Part I. Stiffness
,”
Acta Mater.
,
51
, pp.
1341
1350
.10.1016/S1359-6454(02)00528-1
15.
Mohr
,
D.
,
2005
, “
On the Role of Shear Strength in Sandwich Sheet Forming
,”
Int. J. Solids Struct.
,
42
(
5
6
), pp.
1491
1512
. 10.1016/j.ijsolstr.2004.07.012
16.
Abaqus
,
2003
,
Reference Manuals v6.4–1
,
Abaqus Inc
,
Providence, RI
.
17.
Kelsey
,
S.
,
Gellatly
,
R. A.
, and
Clark
,
B. W.
,
1958
, “
The Shear Modulus of Foil Honeycomb Cores
,”
Aircr. Eng.
, pp.
294
302
.10.1108/eb033026
18.
Grediac
,
M.
,
1993
, “
A Finite Element Study of the Transverse Shear in Honeycomb Cores
,”
Int. J. Solids Struct.
,
30
, pp.
1777
1788
.10.1016/0020-7683(93)90233-W
19.
Allen
,
H. G.
,
1969
,
Analysis and Design of Structural Sandwich Panels
,
Pergamon
,
Oxford
, UK.
20.
Zenkert
,
D.
,
1995
,
An Introduction to Sandwich Construction
,
Engineering Materials Advisory Services Ltd
,
Birchwood Park, UK
.
21.
Evans
,
A. G.
,
Hutchinson
,
J. W.
, and
Ashby
,
M. F.
,
1998
, “
Multifunctionality of Cellular Metal Systems
,” Progress in Mtls. Sci.,
43
(
3
), pp.
171
221
.
22.
Rébillat
,
M.
, and
Boutillon
X.
,
2011
, “
Measurement of Relevant Elastic and Damping Material Properties in Sandwich Thick Plates
,”
J. Sound Vib.
,
330
, pp.
6098
6121
.10.1016/S0079-6425(98)00004-8
23.
Lebée
,
A.
, and
Sab
,
K.
,
2010
, “
Transverse Shear Stiffness of a Chevron Folded Core Used in Sandwich Construction
,”
Int. J. Solids Struct.
,
47
(
18
19
), pp.
2620
2629
.10.1016/j.ijsolstr.2010.05.024
You do not currently have access to this content.