Compressive Stress-Strain Relationships of Layered Solid Foams

stress (kPa)

5.

initial height of foam a (mm)

h

a

20.

coefficients for foam a

c

1a



-1

kPa



3.2

c

2a

0.4

c

3a

0.75

initial height of foam b (mm)

h

b

10.

coefficients for foam b

c

1b



-1

kPa



4.6

c

2b

0.45

c

3b

0.7

initial height of foam c (mm)

h

c

5.

coefficients for foam c

c

1c



-1

kPa



2.2

c

2c

0.3

c

3c

0.8

axes maxima

strain max.

1.

stress max.

20.

This Demonstration calculates and plots the sigmoid compressive stress-strain curve of hypothetical slabs composed of three layers of solid foams having different mechanical properties and thicknesses. It also calculates and displays, separately, the individual components’ stress-strain curves. Each layer is characterized by the foam’s compressibility model equation, whose coefficients can be adjusted, and by its initial thickness, which also can be adjusted.