In isotropic materials, stress and strain are related through Hooke’s Law, which states that stress is proportional to strain. The relationship between stress () and strain () can be expressed by the following equation:
where:
- is the stress (measured in units of force per unit area, such as Pascals (Pa) or pounds per square inch (psi)).
- is the strain (dimensionless, representing the deformation of the material).
- is the Young’s modulus or modulus of elasticity (measured in units of pressure, such as Pascals (Pa)).
For isotropic materials, Young’s modulus remains constant regardless of the direction of the applied force or strain. This assumption simplifies the stress-strain relationship.