Hello,

This question is an update to my previous inquiry on using the Holzapfel model to simulate the material response of a tubular fibre-elastomer composite. I believe I have achieved what I hoped to do but I would like someone to confirm as the documentation and literature of such applications of Abaqus is quite spotty.

I am trying to model the distension of an inflated rubber tube that has fibre families in the longitudinal direction (along the length of the tube) and the circumferential direction (wrapping around the tube). Per the advice given in my last post I have made a 3D 'slice' of the cylindrical tube (1/12th of the tube's circumference) and applied cyclic symmetry conditions.

Next I applied a discrete material orientation that followed the curve of the tube, where axis 1 is in the longitudinal direction, axis 2 is in the circumferential direction, and axis 3 is normal to the tube surface.

Next I edited the .inp file directly to specify the proper directions. I can attach the file directly if needed but the relevant section of code is the *Orientation section which I have edited to say

*Orientation, name=Ori-1, system=RECTANGULAR, local directions=2
Ori-1-DiscOrient
1, 0.
1, 0, 0
0, 1, 0

I added the last 2 lines, and Ori-1-DiscOrient is the discrete orientation, listed fully elsewhere in the .inp file. Running this .inp file yields usable results. The key is that I want to ensure that the 2 lines I added specify the local directions in terms of the discrete material orientation, not the global coordinate axes.

If anyone can confirm this for me, then that would be greatly appreciated. Thank you all.