**Secant Modulus:** Secant modulus is the
slope of a line drawn from the origin of the stress-strain diagram
and intersecting the curve at the point of interest. Therefore, the
secant modulus can take different values depending on the location
of intersect. The figure below shows how the secant modulus is
obtaind at point A on the curve. The secant modulus can be
expressed as a percentage of the Young's Modulus (e.g., 0.7E or
0.85E), and it is used to describe the stiffness of a material in
the inelastic region of the stress-strain diagram. Secant modulus
is commonly denoted by E_{s}.