Creep behaviour of Polyethylene

[Ching]

Hi Everybody,

I am designing polyethylene balloon for nucleus replacement in interverbral disc using ABAQUS. I need to test creep behavior of that material. Can anyone help me in doing this. I defined material as elastic and i have the young's modulus and poisson's ratio with me. I am new to this field and I read abaqus manual, from which i understood a little. I am trying to write the code for the creep. If anyone has the ABAQUS code for this, i will be very very happy.

W8 4 your reply,
Ching

[Jorgen]

I have done tons of work on polyethylene and I am very familiar with the creep behavior of this material. In your case the first thing you need to decide is how accurate you need your simulations to be. You can use a simple linear viscoelastic model if you are only interested in "very small strains" and you are not that concerned about the accuracy. If you want the best possible accuracy you will need to use a more advanced material model (such as the Hybrid Model).

Also, do you have experimental data for the particular type of PE that you are interested in?

- Jorgen

[Ching]

Hi Jorgen,

Thanx for your reply. i am dng modeling and I am implanting the polyethylene balloon in the vertebra and ill simulate using ABAQUS. Actually i am new to this field. I don't think Hybrid option will be there in ABAQUS if i am not wrong. I want the viscoelastic constant values like shear compliance and volumetric compliance values, some other constants like Kr something like that.... I need those values so that i can put those in my model and i can run the model using ABAQUS. Is there anyway by which i can contact you?

waiting for your reply.
Ching.

[Jorgen]

What type of experimental data do you have? Would you be able to run additional tests if needed?

- Jorgen

[Ching]

Hi Jorgen,

In order for me to test the viscoelastic properties of polyethylene,i need to define the constants as i told u earlier. Is there anyway by which i can contact u?So far i run the many models before including the viscoelasticity term. Actually i am stucked up here.So far i got good results and now i need to do the creep test which i am not able to do.i need the viscoelastic constants for the PE.

Thank you,
Ching