Metal Foams: A Design Guide

146 Metal Foams: A Design Guide
ψ =
W
b 2 ρ s
Optimum
density, (ρ c /ρ s )
0.01
0.008
0.006
0.004
0.002
0
0.04
0.03
0.02
0.01
0
0
a
E c/E s = (ρ c/ρ s) 2
b
Wrinkling,
buckling
E c/E s = (ρ c/ρ s) 2
E c/E s = 3(ρ c /ρ s) 2
E c /E s = 3(ρ c /ρ s ) 2
1 2 3 4 5
Π =
P
λE fb
Wrinkling, yielding,
buckling
(10 5 )
Yielding,
buckling
Figure 10.19 Global weight minima for sandwich and hat-stiffened panels
Other configurations
Corresponding diagrams for panels and columns (Budiansky, 1999) are
presented on Figures 10.18–10.20; associated buckling modes are indicated
on the insets. Results for minimum weight flat sandwich panels at a fixed core
density, c/ s D 0.1 (Figure 10.18) are not especially promising. There is only
a small domain of weight advantage, arising when sandwich construction is used