Machine Design - mechanical properties

1. Mechanical Properties

2. Material
Properties
1) Elasticity : It is the property
of the material by which it
can regain its original
shape & size when applied
load is removed.
1) Plasticity : The property
which enables the material
to regain its original shape
& size when applied load
is removed.

3. 3) Stiffness : Ability of the material to resist the deformation
under the load.
4 ) Ductility : Ability of the material to deform under the load
condition. measured in percentage of elongation or
reduction in cross section,

4. 5) Brittleness : Ability of the material to fail without the
deformation. Less than 5% elongation is considered
as a brittle material.
6) Malleability : property which allow material to deform without
rupture. it is considered when compressive load is applied.

5. Stress Strain
Diagram
Stress strain diagram for ductile material

6. • PROPORTIONAL LIMIT :
It is the maximum stress at which the stress is
proportional to strain and above this limit the plastic
deformation of a material occurs. That is nothing but the
hooks law. Which is given as,
stress / strain = a constant
• Here the constant is known as the Modulus of elasticity .

7. • Elastic limit : even if material is stressed beyond the
proportional limit , it can regain its original shape and
size. That is called elastic limit.
• Yield limit : it stress applied beyond elastic limit then
plastic deformation takes place. For ductile material
two yield point is obtained that is denoted by the
Y1&Y2.
• Ultimate point : maximum value of the stress which
is applied beyond the yield point .
• Fracture point : The value of the stress for which

8. 7) Resilience : Ability of the to absorb the
energy within elastic limit.
Modulus Of Resilience

9. 8) Toughness : Ability of the material to
absorb the energy without fracture.
Modulus Of Toughness

10. 9) Creep : The progressive deformation of the
material under continue and loading at a high
temperature.
Stress Vs Time Diagram For Creep test