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Norton creep constants

    • Chandra Sekhar Narra

      Dear Group members,

      Iam working on creep in Ansys. A bending test for the creep is performed for 210hours at two stress.  From this test, i have only deflection along the length of the sample.I have a question, how to derive the Norton creep constants from the Creep bending test data ? Is there any procedure to calculate creep coefficients from the deflections? Can anyone suggest some method/procedure for this?

      Thanks in advance!

      Kind regards


    • John Doyle
      Ansys Employee

      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.

    • Chandra Sekhar Narra


      Thank you very much for your response.

      I have 3 deflections at 3 different times(200,500and 1000hours),From this I can get deflection vs time. Will it helpful to derive rate dependency?

      And I know the dimensions of the sample.

      I will look into 6.3 Section.



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