Page 68 - Polymer-based Nanocomposites for Energy and Environmental Applications

46 Polymer-based Nanocomposites for Energy and Environmental Applications

Table 2.6 Experimental data of sandwich composites [37]
Type of core No. of specimen Maximum load (N) Average load (N)

Neat polycore 1 730 700
2 596
3 774
1 1170 1073
TiO 2
2 1047
3 1003

beams and the natural frequencies of sandwich beams are affected directly by the face
materials; decrease by increasing the fiber orientations of the graphite/epoxy face lam-
inates and increasing the thickness of the cores increases both the natural frequencies
and the loss factors of the sandwich beams. Because of a better cross-linking, the phe-
nolic resin has a loss factor greater than that of epoxy resin. The experimental results
agree satisfactorily with those from finite element analysis. Fig. 2.19 shows the natural
frequencies of sandwich beams for varied cases from experiment and finite element
analysis.
Hosur et al. [39] have fabricated the sandwich panels with neat and nanophased
foam cores and three-layered plain weave carbon fabric/SC-15 epoxy-nanoclay com-
posite face sheets. Sandwich panels are fabricated with different types of core and face

5000 Experiment
[0] 4 /4mm core
[0] 4
4000 [+30/–30] S S
[+45/–45]
Natural frequency (Hz) 3000 FEM [90] 4 /4mm core
[+60/–60]
S

[0] 4
2000
[0]
4
[+45/–45]
1000 [+30/–30] S S
[+60/–60] S
[90] 4
0
1 2 3
Mode number
Fig. 2.19 Natural frequencies of sandwich beams from experiment and finite element
analysis [38].