1. STRESS-STRAIN CURVE:
Stress-strain curves will have a modulus of elasticity, the slope leading up
to the yield point. Along this line, a material can take the pressure and
will only elastically deform. Meaning, the material will go back to its
original state without a change in its properties or dimensions.

2.  Its like bending a paperclip, the paperclip be slightly bent without
the shape changing. Once you bend the paperclip far enough, the
paperclip will reach its yield point and begin to plastically deform.
Plastically deform means you have permanently altered the shape and
now you begin to effect the strength of the material.

3. STRESS-STRAIN CURVE:
 If stress is continually applied, let’s say as a tensile test, then an
ultimate tensile strength will have been reached. This is where plastic
deformation continues and worsens. And eventually a breaking point
for all materials will have been reached, when discussing most metals;
the breaking point is less than the ultimate tensile strength due to the
loss in cross sectional area.

4. There are many materials that will also break at its own yield point, which can
include glass, some plastics, and cast iron. The actual stress-strain curve really
depends on the material that is being tested.
There are two types of material.
1-Brittle materials
2-Ductile materials

7. Stress-Strain Curve Diagram for Brittle
Materials:
Brittle Materials:
Brittle materials are those substances which
rupture occurs without any noticeable prior
change in the rate of elongation.
For example: cast iron, glass, and stone etc.

9. Stress-Strain Curve Diagram for Brittle
Materials:
Ductile Materials:
Ductile materials are characterized by their ability
to yield at normal temperatures which includes
structural steel, as well as many alloys of other
metals etc.

11. Thank You
(Mehdi Balti)
You can mail me at mehdileo05@yahoo.com
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