The largest value of the stress
for which the material will return to its original length after the stress
is removed is called the elastic limit. If the material is stressed beyond
this limit, then it behaves inelastically and will have permanent deformation
Young's Modulus also known as the Elasticity Modulus of a material is the ratio of the stress versus the strain within the Elastic region. This is usually found from the slope of the stress vs. strain curve.
Elasticity Modulus = Stress / Strain
This is a more generalized version
of the Hook's law, similar to the spring constant.
The ultimate strength is defined
as the maximum stress that a material can withstand before it ruptures.
It is determined by dividing the maximum load by the original cross-sectional
area of the test specimen.
A material stressed beyond its
plastic region reaches a stage, with very large displacements, where the
material ultimately breaks. This point is called the Rupture Point of the
In the elastic region, there is a straight line relationship between stress and strain. Within this loading range, if the force is removed, the structure will return to its original dimensions. The slope of this linear portion describes a structure's elastic or Young's Modulus, and is calculated as stress/strain.
Resilience is the capacity of a material to absorb energy when it is deformed elastically and then, upon unloading to have this energy recovered.
It is represented by the area
under the curve in the elastic region.