Exponential Law
When the stress is below the tensile yield stress, the material behaves elastically. After yielding has occurred, the exponential law can be represented by the graph shown below:
In the case of the exponential law the relation between stress and strain can be represented by the equation:
σ = σy + σlimit [1–exp(-m εp)]
where:
• εp is strain
• σlimit is the hardening limit for the material
σlimit has the same units as stress. The hardening limit of a material is greater than 0.
• m is the exponent which is a constant for the material
The exponent is dimensionless. The value of exponent is greater than 0.
If you select Define By Tests then you must curve fit the values of Hardening Limit and Exponent. If you clear the Define By Tests check box, then you must specify constants for Hardening Limit and Exponent.
