What Exactly is a Foam’s Tensile Strength

Unit of measure	kPa
Test method	JIS K6767-1976

Tensile strength σ_UTS, or S_U measures the force required to pull a piece of foam to the point where it breaks.

Tensile strength is measured in units of force per unit area. In the SI system, the units are newtons per square metre (N/m²) or pascals (Pa), with prefixes as appropriate. The non-metric units are pounds-force per square inch (lbf/in² or PSI).

The calculation for Tensile Strength is done by stretching a dumbbell shaped piece of foam of a particular shape, and measuring the maximum force applied until it breaks.

Calculation of Tensile Strength (T)

T=F/(Wt)

Where, F = maximum load until test piece breaks (N)

          W = width of test piece (m)

            t = thickness of test piece

Example

Using our testing equipment we have a piece of foam that is 10mm thick and 10mm wide, and 70N of force was required to break it.

From above, T=F/(Wt)

Where, F = 70N

           W = 0.01m

                       t = 0.01m

therefore       T = 70/(0.01 x 0.01)

                                  = 700kPa

Thus, the Tensile Strength of the tested foam is 700kPa.