Clay and Sand hypoplasticity UMAT and Plaxis implementations, including UMAT-Plaxis interface

Description: Interface between umat and Plaxis (UsrMod) user defined model standards. Includes clay and sand hypoplastic model implementations, including the intergranular strain concept versions of the model. Description of the implementation and a user manual can be found here.

The implemented sand model has been published by von Wolffersdorff (1996). The implementation also contains Niemunis and Herle (1997) extension for predicting small strain stiffness effects.

The implemented clay model has been published by Mašín (2014). This model is an anisotropic version of the general clay hypoplasticity model described thoroughly in Mašín (2013). Structure of the anisotropic stiffness matrix described in Mašín and Rott (2014). Structured-soil specific model features are described in Mašín (2007). The model can be used with the intergranular strain concept, its original formulation is in Niemunis and Herle (1997), enhanced formulation implemented is described in Mašín (2013). Most of the cited journal papers available here for free download in the form of PDF preprints.

Interface implementation between umat user defined constitutive model format of Abaqus and User_Mod format of Plaxis finite element code. Comes pre-compiled along with clay and sand hypoplastic model implementations, can be used as a base for implementation of other constitutive models.

Authors: The original umat implementation has been developed by Claudio Tamagnini in 2005. It has since been further developed and updated to new models by David Mašín. The original interface implementation has been developed by prof. P. A. von Wolffersdorff in 2005. It has since been further developed and updated by David Mašín.

Related publications (clay hypoplasticity):







Related publications (sand hypoplasticity):






Associated Software and Constitutive Models

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7 Comments
  1. Abd Elfattah
    Abd Elfattah 1 month ago

    Dear sir
    i try use the Umat- hypo-plasticity model but i found the following message “”ERROR in job messaging system: Error in connection to analysis”
    can you help me

    • David Mašín Author
      David Mašín 1 month ago

      Hi, this is probably some Abaqus-related compilation error.
      I am not expoert in this, but it seems to me this is not a problem of umat itself.
      I recommend you firstcopy elastic umat from ABAQUS manual and try to run elastic analysis. Once this works, you can move to complex umats like this hypoplastic one. Regards David

  2. Abd Elfattah
    Abd Elfattah 1 month ago

    I appreciate for your quick response, when i used Umat SANISAND model, it is seem ok and no problem related compilation, however this model is very complicated to estimated required parameters. in contrast, when i used Umat for hypoplasticity model, this problem was appeared.

  3. Abd Elfattah
    Abd Elfattah 1 month ago

    Thank you very much for your cooperation
    I will try once again, I will tell you the Updates

  4. Cristian Rodriguez Lugo

    Respected sir

    Thanks for your hypoplastic subroutines. I am running the implementation for sand in plaxis but I get the following error:

    Intel(r) Visual Fortran run-time error
    forrtl: severe(9): permission to Access file denied, until 1, file C:\Program Files (x86)\Plaxis\Plaxis 2D\ fort-1
    Image PC Routine Line Source
    usdm_hps64.dll 00007FF9ADD31D2F Unknown Unkown Unknown

    Do you have any idea what could be the reason for this error message?

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