Table 10-1.—Tensile Strengths
Elongation
The term elongation d e s c r i b e s
deformation, lengthening, or stretching caused by
a tensile force. It’s what you do when you stretch
a rubber band. The ability to elongate gives stretch
to a fabric. Elongation is expressed as the
percentage of stretch over the original length. For
instance, if a tape has 10 percent elongation, a
10-inch
breaks.
percent
piece will stretch to 11 inches before it
Parachute specifications call for 20-25
elongation.
Elasticity (or Elastic Recovery)
The term elasticity describes the ability of a
fabric to elongate (or stretch) when tension is
applied, and to recover its original shape when
the tension is released. If you stretch a rubber
band and then let it go, it comes back to its
original size. To test the elesticity of a material,
stretch it 4 percent and then measure to see how
closely it returns to its original length. A fabric
that returns to within 75 to 95 percent of its
original length after being stretched is said to
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