Reply To: Norton creep constants

[John Doyle]

Do you have deflection vs time or just the final deflection?

If you only have the final deflection, I don’t think you have enough information to derive rate dependency.

If you have deflection vs time, you might be able to derive an equivalent creep strain (creq) and creep strain rate (dcreq), from the measured deflections and times. 

You would need to also know the dimensions of the test sample to do this.

It sounds like you have two ‘constant’ stress values from the test.  

With the above information you might be able to curve fit Norton Creep, Strain Hardening Creep, or Modified Strain hardening Creep .

Please refer to Section 6.3 of the Mechanical APDL Material Reference Guide for minimum data needed to perform creep curve fitting (‘Table 6.7:  Creep Model and Data/Type Attribute ‘) for the different creep models and corresponding curve fitting procedural details.