×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Female breast under zero-gravity
2

Female breast under zero-gravity

Female breast under zero-gravity

(OP)
Hi every one,

I am doing a Biomechanics research of female breast cancer, i am using ANSYS 12  to solve my FEM problems.

I have the mesh of deformed breast under itself weight (from a 3D RMI images) and i would like to know if it is possible to get the zero-gravity mesh of that breast. So i can apply the gravity in another direction.
 

  

RE: Female breast under zero-gravity

(OP)
Hi again, we know the deformed shape of breast under gravity, so we need to solve a backward problem to have a reference state. Could ansys do that? Help needed!

Thanks and best regards
 

RE: Female breast under zero-gravity

I think it can.  If you know the deformed shape w/ 1g of load couldn't you apply a -1g inertial load and solve for the undeformed shape in this manner?

The most correct way would be to apply stresses as initial conditions to the deformed configuration of the breast and let the problem find the undeformed configuration.  I seems that it'd be difficult to know what stresses are present in the tissue to apply as initial conditions though.

-Brian

RE: Female breast under zero-gravity

(OP)
Hi brian, thank you for reply, actually i tried to apply -g internal load, maybe it is good for approximation but didn't give the exact result due to shape deformation and displacement of the center of mass of the studied geometry and for each elements.

Actually i don't know how to apply stresses as a initial conditions because i just have the final deformed shape and the internal force, can you please give me some hints to do it?
thank you again
 

RE: Female breast under zero-gravity

Initial stresses are applied with the INISTATE command.  That's the easy part...knowing what those stresses and/or strains are is the difficult part. ;)

RE: Female breast under zero-gravity

I'm just curious... do you have material property data for... erm... boob?

RE: Female breast under zero-gravity

(OP)
Hi brain, my question was about the difficult part. ;)

Hi flash, yes i know the material propert actually breast has three tissues and all of them are hyperelastic (rubber-like) material.

RE: Female breast under zero-gravity

Perhaps the undeformed shape could be approximated with by a "guess-and-check" methodology on a 2D model. You could build a parametric model of an undeformed breast, apply a gravity load and adjust the initial shape based on the results. As long as the model runs quickly, you could probably hone in on a shape in a reasonable amount of time.
You could probably automate this process, but seeing as there are likely quite a few parameters defining the shape of the breast, it might be easier to adjust them manually.  

RE: Female breast under zero-gravity

(OP)
Hi again flash, thank you for your reply, it is a good idea, but i have a huge 3D mesh with 3 milliones of nodes and it is imposible to be adjusted manually.
I have another question, i start to use ansys 13, in this version there is no real constant for shell 181 or shell 281 and I dont know how to define the thickness of shells!!  

best regards and merry christmas  

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources