It gives the complete description of the Solid Mechanics

1. BASICS OF
STRENGTH of
MATERIALSby
ARAVINDKUMAR B

2. S• olid mechanics is the branch of
mechanics that studies the behavior of
solidmaterials

3. Solid Mechanics Dealswith
• Motion and deformation of material under action of
• Force
• Temperature change
• Phase change
•Other external or internal agents These changes
lead us to some
properties that are called Mechanical properties

4. MechanicalProperties
• Ductility: ductility is a solid material's ability
to deform under tensile stress
Hardness of a material may refer to resistance
to bending, scratching, abrasion or cutting.
Impact resistance is the ability of a material to
withstand a high force or shock applied to it over
a short period of time
Plasticity: ability of a material to deform
permanently by the application of force

5. MechanicalProperties
• fracture toughness is a property which describes the ability of a material containing a
crack to resist fracture
• Elasticity is the tendency of solid materials to return to their original shape after
being deformed
• Endurance strength/ Fatigue strength: The highest stress that a material can withstand
for a given number of cycles without breaking —called also endurance strength
• Endurance limit: In fatigue testing, the maximum stress which can be applied to a
material for an infinite number of stress cycles without resulting in failure of the material
is called Endurance limit
• Creep Resistance: It’s the ability of a material not to deform
permanently or slowly under the influence of Mechanical Stress.
Creep means Time Dependent Deformation

6. Creep(SlowDeformation)
• Reasons Behind Creep
• Long term stress below yield strength
• Material subjected to long term heat when in operation
• Working condition near to the melting point of the material
• Total time of use
Creep is a time dependent phenomenon
Stages of Creep:

7. What to Learn ?
• What is pressure and what is stress?
• What are the different types of stress?
• What is strain?
• How stress and strain can be correlated? (Hook’s law)
• Stress – strain diagram.

8. Force applied on fluid – pressure
Force applied on solid body – stress
Pressure Stress

9. Different stresses
1) Axial stress
1) Tension
2) compression
2) Transverse stress
1) Bending
2) Torsion

10. Axial stress
Tension
Sectional area decreases
Length increases
Compression
Sectional area increases
Length decreases
Stress(σ) = 𝑟𝑒𝑠𝑖𝑠𝑡𝑖𝑛𝑔 𝑓𝑜𝑟𝑐𝑒
= 𝐹
𝑟𝑒𝑠𝑖𝑠𝑡𝑖𝑛𝑔 𝑎𝑟𝑒𝑎 𝐴
Unit of stress in SI unit is N/𝑚2

11. Transverse stress
Bending stress
Due to bending load, deformation occurs
Torsional stress
Due to torsional load, twisting occurs

12. Shearing Bearing Tearing
stress stress stress
Stress due to two parallel loads

13. Strain
Strain means relative change in shape or
size implies that it is dimensionless and
has no units.
Deformation per unit length is strain.
It is the ratio of change of shape to the
original shape.
It is denoted by ϵ (or) e

14. Hook’s law
It state that within elastic limit, stress is directly proportional to strain.
It is a material property which shows that how much
external force it can withstand.
For mild steel, modulus of elasticity is 200 GPa.

15. Stress strain curve
The shaded area shows
the feasible region for
Hook’s law. I.e. It shows
the proportional limit.