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UMAT for non-linear viscoelastic model

Submitted by BMEstudent on

Hi all,

I'm using Code-Aster (FE solver) and I need to implement a UMAT subrouting to model a non-linear viscoelastic model in it.

The model is combination of viscoelasticity+ Ogden hyperleastic model. I was thinking of 2 approaches:

1. I wonder do you know where I can find such a subroutine?

2. I've seen linear viscoelastic subroutine and maybe I can find another subroutine for hyperlelastic part, I wonder how can I combine this two models to a non-linear viscoelastic model? 

I really appreciate your help

BME 

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fendi

Hi,

For 3D viscoelastic model, you can refer to the following:

Kaliske M. and Rothert H. 1997. Formulation and
Implementation of Three-Dimensional Viscoelasticity at Small and Finite Strains.
Computational Mechanics, 19: 228-239.

which is the one used in Abaqus version 6.8 and before.

For a simple 1D viscoelastic model:

Goh S. M., Charalambides M. N. and Williams J.
G. 2004. Determination of the
Constitutive Constants of Non-Linear Viscoelastic Materials. Mechanics of Time-Dependent Materials, 8: 255–268

Both models in the papers can be used with any hyperelastic model for large deformation, where the latter paper can be implemented explicitly in any spreadsheet using a least squares method. Good luck.

Fendi

Sat, 06/23/2012 - 22:09 Permalink
BMEstudent

 

Hi,

Thank you
guys, especially Fedi for very good references. I’m not very good at writing codes,
and also I know some software produces such subroutines (like ZMAT).  I was wondering do you know any sources to
fined UMAT subroutines for viscohyperleastic models. Otherwise I should prepare
myself to write the code!

Thanks

 

Wed, 07/04/2012 - 16:10 Permalink
Frank Richter

This thesis combines hyperelastic with viscosity, but without Ogden:



DISS. ETH NO. 18135

INVERSE ANALYSIS IN ROAD GEOTECHNICS

A dissertation submitted to ETH ZURICH

author: CARLO RABAIOTTI

 

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Ruhr-University
Bochum
Germany

Thu, 07/05/2012 - 17:03 Permalink