A question on Arruda-Boyce model

[LUSONG]

Hello everyone. :D
Hello Jorgen_Bergstrom.
I am using Arruda-Boyce model to calculate the hyperelastic material. The FEM software I used is ABAQUS. Now, I have a question. Is this Arruda-Boyce model ABAQUS offered the same with the "Arruda-Boyce model" in paper " Constitutive modeling of UHMWPE under large-deformation and cyclic loading conditions"? As we know, the "Arruda-Boyce model" in paper " Constitutive modeling of UHMWPE under large-deformation and cyclic loading conditions" is viscoelastic-plastic, not hyperelastic.
Are there any different between these two models?
As I understand,the model ABAQUS offered is more like the 8-chain model. Why did they call this model Arruda-Boyce model too?
Also, I have another question. That is how I can express or plot the hyperelastic Arruda-Boyce model as figure in the paper.

Thanks
lusong

[Jorgen]

That is a good question and a common source of confusion. When Ellen Arruda did her PhD thesis at MIT she developed two separate model: one hyperelastic model that is commonly refered to as the 8-chain model, and one viscoplastic model which is often referred to as the Arruda-Boyce model.
Now, the confusion is that ABAQUS does calls the 8-chain model the Arruda-Boyce model.

I am not sure I understand your second question. If you want to plot the results from the 8-chain model you can simply run an ABAQUS simulation using that model, and then extract and plot the results.

Jorgen

[LUSONG]

Thank you Jorgen. :D Your reply make me understand the difference between the two Arruda-Boyce model.

My second question is whether i can make the rheologicl representation of the hyperelastic model (8-chains model) as you do in your paper "Constitutive model of UHMWPE......". As you know , we always use spring element to express elastic model. How to express the hyperelastic model?

Thanks
Lusong

[Jorgen]

I am still not quite sure I understand your question. Yes, you can use the 8-chain hyperelastic model. In my paper "Constititutive model of UHMWPE..." I use that hyperelastic model as one of the building blocks in a more advanced viscoplastic framework.

-Jorgen

[LUSONG]

Hello Jorgen, now i have another question.
I want to use ABAQUS software to simulate the mechanic property of UHMWPE. The constitutive model for UHMWPE is viscoelastic model.
I want to use the viscoelastic model ABAQUS offered. As you know, the viscoelastic model ABAQUS offered must combine with a elastic model.So, in order to express the nonlinear property of UHMWPE,i choosed the hyperelastic Arruda-Boyce model. My question is how i can plot this model (viscoelastic model combine with Arruda-Boyce model). [/quote]

[Jorgen]

Hello Lusong,

Your strategy is valid: first specify which hyperelastic material model that you are interested in. Then, specify the prony series terms.

Finally, to plot the predicted stress-strain response you simply need to create and run a one-element finite element simulation that imposes a strain or stress history that you are interested in.

Cheers,
Jorgen