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Usage/ Validity of Bergstrom Boyce model for an elastomer??

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  • Usage/ Validity of Bergstrom Boyce model for an elastomer??

    Hello all,

    I am trying to calibrate the parameters of Bergstrom-Boyce material model by curve fitting FE results to experimentally determined uni-axial stress strain curves for different loading rates.
    • In the literature where the model is used for elastomers, FE results are always compared to some experiments conducted on pre-stretched samples (after removing the influence of Mullins effect)

    I am interested in simulating the virgin stress strain response (which is load rate dependent) of the material I am studying.
    • So the question is, can the Bergstrom-Boyce model be used to describe the stress strain response of a virgin elastomeric material?

    My attempt to optimize the model parameters with the experimental data is shown below. Although the (stress strain) curve fit looks good, there seems to be a mechanism (a minimum in the derivative curve) that is probably not captured in the simulated results.

    Green curve is from experiments and the grey ones are from simulations for different parameter sets. (Please refer the attached image)
    I have posted the photo as an answer as I always get some error while uploading it in the question

    I would be really glad for any ideas, suggestions and links to other literature sources.

    Please contact me for more info if required.

    Thanks in advance!

  • #2


    • #3
      Hi everyone

      I am currently modeling the Static and dynamic shear modulus tests of an anti seismic bearing in order to achieve the results of the actual shear modulus tests conducted on the bearings.

      Abaqus is new to me and i have to following questions:
      1. The only test information regarding the elastomer i have is the direct compression tests on identical samples tested at EdF in france which is used to plot a stress strain curve. i do not have the uniaxial, biaxial or planar test results of the neoprene. would this be acceptable data to evaluate as the material test data (uniaxail compression) for a hyperelastic material?
      2. The tangential force is applied to the shear plate at a rate of 8kN/min to obtain a minimum tangential force of 71.28 kN for two bearings tested in a sandwhich configuration to a bearing distortion of 42 degrees. These are the parameters for conducting the test. how would i incorporate these constraints to my model?

      your assistance would greatly be appreciated.


      • #4
        If you have a uniaxial stress-strain curve, then you can calibrate an approximate hyperelastic material model. You can assume a large bulk modulus, and then calibrate the hyperelastic model. I would select a simple hyperelastic model such as the Neo-Hookean, or Arruda-Boyce Eight-chain model. Both of these models are I1-based, and therefore safe to calibrate to uniaxial data alone.

        Jorgen Bergstrom, Ph.D. PolymerFEM Administrator