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Help simulating deformation of red blood cell — Ansys Learning Forum

# Help simulating deformation of red blood cell

Member Posts: 10

Hello,

I'm new to Ansys and need some help simulating the deformation of a red blood cell. I've modeled and meshed my model but finding trouble moving forward. This is my model so far:

The model is a quarter of a red blood cell, with a silicon bead attached to it. I want to apply a force to the bead causing the cell to deform similar to this:

If any advice on how I can move forward and achieve this sort of deformation will be greatly appreciated

Thank you

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## Best Answer

• Member Posts: 11,369
Accepted Answer

I recommend you delete the force and instead apply a Remote Displacement.

That way you can ramp on a displacement of your choosing.

Probe the results to obtain the Reaction Force at each load step of the displacement.

## Answers

• Ansys Employee Posts: 262

Hello @Wazawaki,

Could you provide more details about the physics of your problem? What is the bead's function? What are the forces that are causing the cell to deform? Is it fluid pressure or is it the bead that is pulling the cell? From the images above it looks like the bead is trying to pull the RBC. Since you are modelling half of the cell you need to use a symmetry object to fix appropriate degrees of freedom along the symmetry plane. You could refer this tutorial https://www.youtube.com/watch?v=RETzoXbbwBA. Once this is done you could apply a force/displacement along x axis to pull the bead. It looks like you have already defined the bonded contact which should work.

Regards,

Ishan.

• Member Posts: 10

Hi @1shan ,

Thank you for your reply, that's correct the bead will be pulling the cell in order to deform the cell. I have implemented the symmetry object into the model, would it be okay to explain how would I go about applying the stretching force shown in the second image onto the bead into deforming the cell?

Thank you again, your help is greatly appreciated!

• Member Posts: 11,369

Your model is pulling one red blood cell with 2 beads, one on each side of the symmetry plane.

If you want your one red blood cell to be pulled with 1 bead, then you have to put the bead on the symmetry plane and cut that in half too.

• Member Posts: 10

Thank you for the help, I have now made those adjustments. Would you be able to explain how I can apply a force on the bead in the x-direction in order to pull and deform the cell as shown in my second image?

Thank you again for the help!

• Member Posts: 11,369

I don't understand why you are asking this question because I can see in the image that you have already applied a force in the X direction to the bead.

What happens when you solve?

Under Analysis Settings, have you turned on Large Deflection?

Have you set Auto Time Stepping to On

Have you set the Initial and Minimum Subseps to 10?

Set the Maximum Substeps to 100.

• Member Posts: 10

Hi,

When I apply the force the simulation is unable to complete full and I get the following result using a force of 10pN:

Would you know what could possibly be causing this?

Thanks again.

• Member Posts: 11,369
Accepted Answer

I recommend you delete the force and instead apply a Remote Displacement.

That way you can ramp on a displacement of your choosing.

Probe the results to obtain the Reaction Force at each load step of the displacement.

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