Model from shape equation

[m3tro]

Hello everybody,

I am a bioengineer and I am interested in studying the problem of deformation of body tissues. I have never used ABAQUS so far but I have read about it and it seems exactly what I need to address certain problems that I am having. However, I wanted to make sure of a couple of things before acquiring it.

I have the mathematical expressions of the shapes of the objects I want to study. Say, I want to study the deformations of a solid object whose external surface is defined by the equation z=5-x^2-y^2 (0<z<5) (just an example) or a thin shell with the same shape, subjected to external forces. Would this be easily implemented and meshed in ABAQUS? I have been looking for it but all the help sections talk about simple shapes like cubes and cylinders.

Would the inclusion of an incompressible fluid inside the shell be implemented in the standar version of ABAQUS, or do I need specific fluid dynamics packages?

Thank you for your help.

 

[IceBreakerSours]

I didn't follow the equation but whatever else you've mentioned is doable in Abaqus (or any other modern FE package, really). You don't need any CFD functionality for this purpose. Which soft tissue is of interest to you, by the way? A disc? What are you trying to accomplish?

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[m3tro]

I am trying to model the deformations of a cancer cell subject to external forces. Getting the relaxed, stress-free shape of the cell right is of great importance for the results. That is why I would like to map this shape equation that I have straight into an ABAQUS model.

I have an equation that determines the external shape of the cell in absence of forces, just the same way as x^2+y^2+z^2=1 is the shape of a sphere of unit radius, except much more complex. I'm sure there's some way of mapping it straight into a 3d model but I don't know exactly how.

Thanks for your help.

 

[IceBreakerSours]

Okay, yes, you can use the *parameter keyword to define nodal coordinates and create your geometry from an equation.

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[m3tro]

Thank you! I am happy to hear that it's possible. I was now looking *parameter keyword in the online ABAQUS help and I found this "analytical rigid surface" which seems exactly what I was looking for!

http://abaqus.me.chalmers.se/v6.12/books/usb/default.htm?startat=pt01ch02s03aus19.html

 

[IceBreakerSours]

I thought you were planning on making a cell, which I assume ought to be deformable, isn't it?

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[m3tro]

Oh yes I want it deformable (hyperelastic). But what I meant is that the keyword *SURFACE seems to do the job, doesn't it? Then instead of asigning the surface to a rigid body I would assign it to a deformable shell