Two section bone 1

[fruton]

Hello all,

I have a solid section femur and need the first 1.5mm thickness from the surface to be one material property and the rest of the solid section be another material proerty. This would represent the first 1.5mm thickness of the bone being cortical bone and the internal structure being cancellous bone.

I want to import the model into abaqus for analysis.

What would be the easiest and most reliable way to do this?

The other problem is whenever I important different section models into abaqus (via a step file) it imports it all as one solid.

I have attached the solidworks part file of the bone if it helps.

Thanks

 

[Eltron]

This wouldn't be a school project, would it?

Dan

http://www.eltronresearch.com

Dan's Blog

 

[fruton]

No I am an FE analyst, looking at orthopedic devices. However, I am not so advanced on Soldiworks, therefore I was seeking some guidence on it. Thanks.

 

[SnowCrash]

Eltron, you meanie ;-)
Fruton,
Shell the part; make a cavity to re-create the inner and outer bodies, create an assembly of the two and evaluate that. However, the required thickness is too large for the minimum radius for shelling. Determine the minimum radius and do the shell in layers. Try to do a surface offset and cut the part with that.
As fas as your issue with abaqus, we can't help you here. If there is an alternative to STEP files, avoid that format.


--
Hardie "Crashj" Johnson
SW 2011 SP 2.0
HP Pavillion Elite HPE
W7 Pro, Nvidia Quaddro FX580

 

[fruton]

Thanks SnowCrash, I have tried a few things, without success. I tried to shell at a thickness less than the minimum radius, but still not luck. I tried something with offsets but did not get much further with that either.

Is there any kind of auto surface smoothers in I can use? or any other suggestions?

Thanks.

 

[rstupplebeen]

I do not believe that you will have an easy solution to this problem since your topology does not lend it's self to shelling because of the minimum radius. Because of this you need to prework the model to remove the minimum curvature.

1. Split your model into different sections along the bone so you can work on 1 section at a time.
2. Use tool check to see the minimum radius surfaces.
3. From here you can fillet or do a delete face with tangent propagation.
This may take many steps. Once you have the minimum radius above 1.5mm then try shelling.

For Abaqus I have most success with STEP however SAT (asics) is it's native format some times I also use IGS. Depending on your analysis you could bring in the part as is to Abaqus and then skin the part with shell elements offset in to provide the additional stiffness. Just be sure to knock down the stiffness of the skin by the difference in cortical and cancellous bone. I hope this helps.

Rob Stupplebeen

https://sites.google.com/site/robertkstupplebeen/

 

[rbpmc]

You could try to copy your model and do a scale factor on the copy to simulate the 1.5mm thickness. Use the combine subtract to remove the inner scaled model. This would leave a shell.

 

[EEnd]

A very similar discussion occurred in: thread559-284706.