1. Forging new generations of engineers
Strain
Principles of EngineeringTM
Lesson 5.2 – Strength of Materials
Forging new generations of engineers
Project Lead The Way, Inc.
Copyright 2007

2. Strain

3. Strain
Strain is a measurement of deformation in a structure due to applied forces.
If a rod of length L and constant cross section area A has a force P applied at the end, the deformation will be . L  A P

4. Strain ε=  / L Strain is calculated from: Strain = Deformation
Original Length or
ε=  / L
Strain is deformation per unit length, a
dimensionless quantity

5. Stress- Strain Curve
Stress and Strain are related through the stress strain curve and Hooke’s Law in the elastic region.

6. Stress- Strain Curve Hooke’s Law E is the Elastic Modulus.
E is the slope of the line in the elastic region.