# Thread: Beginner Viscoelastic Question-Abaqus

1. Junior Member
Join Date
2008-12
Posts
26

## Beginner Viscoelastic Question-Abaqus

I have a bunch of test data for a viscoelastic material and I would like to distill this down to a viscoelastic model in Abaqus without using a custom material subroutine. And quite frankly I am not sure where to start.

Data I have:
TCE vs Temp
Viscosity vs Temp
Cp vs Temp

For now I can ignore bulk modulus but I was wondering if someone could give me some guidance in taking the test data and putting this into a shear relaxation modulus. A fit has already been done to get this into a TNM model so I have the TCE (liquid and and solid), time constant, activation energy, and the parameters of a TNM model.

Is it possible to use this information in a way that would not require a series of custom material/property routines? Or is that really the only way?

Any help is appreciated.
DS

2. First, by TCE I assume that you are referring to Thermal Coefficient of Expansion. Is that right?

I am not quite sure what you have mind with the TNM term, however. I use TNM when talking about the Three Network Model. What do you mean by TNM?

The easiest viscoelastic material model to use is a linear viscoelasticity model. To use that model you need both the elastic part of the response, and information about the viscous response. In your case if sounds like you know the viscosity, and hence you can calibrate a one-term Prony series to your viscosity data set. If you then combine that with a hyperelastic material model then you will have a valid linear viscoelasticity model.

Best of luck,
Jorgen

3. Junior Member
Join Date
2008-12
Posts
26
Jorgen,

Yes TCE is the Thermal Coefficient of Expansion. What I am referring to by the TNM model is the Tool-Narayanaswamy-Moynihan method. This is a method of determining the ficitive temperature of a material. I think this is one of the main areas that I am unclear as to getting the data in a form that can be used in a viscoelastic model.

Originally Posted by Jorgen
First, by TCE I assume that you are referring to Thermal Coefficient of Expansion. Is that right?

I am not quite sure what you have mind with the TNM term, however. I use TNM when talking about the Three Network Model. What do you mean by TNM?

The easiest viscoelastic material model to use is a linear viscoelasticity model. To use that model you need both the elastic part of the response, and information about the viscous response. In your case if sounds like you know the viscosity, and hence you can calibrate a one-term Prony series to your viscosity data set. If you then combine that with a hyperelastic material model then you will have a valid linear viscoelasticity model.

Best of luck,
Jorgen

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