Biology for Computer Engineers Course Handout.pptx
Mechanical properties of metals
1.
2. Stress and Strain
In a simplistic sense, stress may be
thought of as Force/Area.
Similarly, strain is the deformation of the
component/original length.
A stress may be direct, shear or torsional -
leading to corresponding deformations.
Stress cannot be measured directly, but
deformation can be.
7. Hooke’s Law
Elastic Deformation
Elasticity :
Elastic deformation is not permanent; it means
that when the load is removed, the part returns
to its original shape and dimensions.
For most metals, the elastic region is linear. For
some materials, including metals such as cast
iron, polymers, and concrete, the elastic region is
non-linear.
If the behavior is linear elastic, or nearly linear-
elastic, Hooke’s Law may be applied:
Where E is the modulus of elasticity (MPa).
S Ee
8. • Property of body by which it retains to its
shape after removing stresses.
• Plasticity = %age elongation + %age
reduction in area.
9. “Ability of a material to resist
deformation.”
Tensile strength: Measure of level of
tensile stress required to make
material fail.
Compressive strength: Maximum
compressive stress that a material
can resist without being crushed.
11. Ductility & Brittleness
Ability of a material by
which it can be drawn
into wires.
Opposite to ductility.
Tendency of a body to
break without being
distorted.
12. Malleability
Ability of a body to be plastically extended in all
directions without breaking under compressive
forces only.
Property by which metals drawn into sheets.
16. • Progressive deformation of a material
under constant load with time.
• Important for some type of engineering
design particularly those operating on
high temperature.
• Tertiary creep > Primary creep >
Secondary creep.
18. When stress is applied on a material then after
certain time it becomes unfit as compared to
new one.
It occurs due to repeated loading and
unloading.