0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 0.045 0.05
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
Stress
(MPa)
Strain (mm/mm)
Quasi−Static Data
3rd Order Least Squares
σ = 2.46ε − 18.44ε
2
− 68.70ε
3
Vibration Response
In order to understand the complex vibration response of a
simplified packaging system containing Arcel
®2
, the nonlinear
constitutive relationship of polymer foam was approximated
using polynomials. Furthermore, classical elements of
viscoelasticity such as time dependent exponential decay
terms were used to capture the rate dependent or viscoelastic
behavior of the material. The experimental stress–strain
behavior, Fig. 3, and stress-relaxation behavior, Fig. 4, of
Arcel
®
was used to identify the unknown parameters of the
model.
9
0 50 100 150 200 250 300 350 400 450
0.02
0.025
0.03
0.035
0.04
0.045
Time (min)
Stress
(MPa)
Foam
L
L
Figure 3: Polynomial fit of the stress-relaxation behavior of Arcel
®
.
Figure 4: Stress-relaxation behavior of Arcel
®
.
2
Arcel® is a blend of expanded polystyrene (EPS) and expanded polyethylene and is manufactured by Nova Chemicals Corporation.
