ID:10.01.03.095

1. AHSANULLAH UNIVERSITY OF SCIENCE &
TECHNOLOGY
Department of Civil Engineering
Presentation On
Axial Stress-Strain Curve
&
Modulus of Elasticity
Presented by
Md. Nafizul Haque
ID: 10.01.03.095

2. What Is Axial Stress?
 A tension or compression
stress created in a
structural member by the
application of a lengthwise
axial load.
 Axial stress is defined as
the force per unit area of
a material.
 i.e. Axial stress = axial
force / cross sectional
area:

3. What Is Axial Strain?
 Increase (or decrease) in
length resulting from a
stress acting parallel to the
longitudinal axis of the
specimen.
 Axial strain is defined as
extension per unit length.
 Axial Strain = extension /
original length

4. Universal Testing Machine

5. Axial Stress-Strain Curve for Brittle Material

6. Axial Stress-Strain Curve for Ductile Material
Typical regions that can be
observed in a stress-strain
curve are:
 Elastic region,
 Yielding,
 Strain Hardening,
 Necking and Failure

7. Elastic behavior
 If the specimen returns
to its original length
when the load acting on
it is removed, it is said to
response elastically

8. Yielding
 A slight increase in stress
above the elastic limit will
result in permanent
deformation. This behavior
is called yielding for
ductile materials.
 The stress that causes
yielding is called yield
stress sy.
 The deformation that
occurs is called plastic
deformation

9. Strain Hardening
 When yielding has ended,
a further load can be
applied to the specimen,
resulting in a cure that
rises continuously but
becomes flatter until it
reaches a maximum stress
referred to as ultimate
stress, su.
 The rise in the curve is
called Strain Hardening

10. Necking & Fracture
 After the ultimate stress,
the cross-sectional area
begins to decrease in a
localized region of the
specimen, instead of
over its entire
length. The load (and
stress) keeps dropping
until the specimen
reaches the fracture
point.

12. Modulus of Elasticity
 The modulus of a material describes how well it resists
deformation. A material with a higher modulus is stiffer
and has better resistance to deformation. The modulus is
defined as the force per unit area required to produce a
deformation or in other words the ratio of stress to strain.
 Modulus of elasticity=Stress/Strain