- It is the resistive force per unit area.
- Stress = (Applied Load, P)/(Cross-sectional area, A)
- Unit- Newton per Sq. meter
- It is the change in length per unit length.
- Strain = (Change in length, dl)/(Original length, l).
- It is also a dimensionless quantity.
- A maximum unit stress to which a material can be subjected and is able to return to its original form after the removal of strength.
Within the elastic limit, Stress is proportional to Strain.
E = (Stress)/(Strain), E is Proportionality Constant called Young’s Modulus of Elasticity.
Within the elastic limit, the extension of an elastic body is directly proportional to the force producing it.
- The Ratio of maximum load which a specimen sustains to its original area of cross-section.
- Unit stress at which deformation first increases, without any increase in the applied load; and it is always above the proportional limit.
- The highest unit stress it can sustain before rupturing.
- Ability to resist deformation under stress.
The factor of Safety (FOS)
- The ratio of failure stress to the allowable stress (of the material).
For ductile Materials
- FOS = Ratio of Syt to σ; where Syt is yield strength of a material
- For brittle Materials
- FOS = Ratio of Sut to σ; where Sut is yield strength of a material