×
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

Pressure load definition in Abaqus Explicit when the surface is constantly changing

Pressure load definition in Abaqus Explicit when the surface is constantly changing

Pressure load definition in Abaqus Explicit when the surface is constantly changing

(OP)
I am trying to simulate a simple model in Abaqus- an elastic spherical shell being sucked into a rigid tube. The diameter to the sphere is greater than that of the tube and I want to study the large deformation of the shell into the tube.
I am unable to define a load to simulate the suction pressure on the shell applied by the tube. I am using Pressure as the distributed load, which can only be defined for a particular surface. In this problem, the surface on which the suction pressure will be applied will constantly change as the shell enters into the tube. I would be grateful if anyone can help me defining such suction pressure.

How to write a user subroutine using VDLAOD

RE: Pressure load definition in Abaqus Explicit when the surface is constantly changing

Actually this is quite similar to the micropipette aspiration problem, only in larger scale and with different material probaly. There are some articles describing such simulations. In these articles you can find different approaches to the problem of suction pressure application. But first of all it is highly advised to use axisymmetric model (if possible in your case). Also make sure that initially sphere is already in contact with pipe.
I can recommend the following articles:
- ”A Finite Element Study of Micropipette Aspiration of Single Cells: Effect of Compressibility” by A.J. Bidhendi and R.K. Korhonen
- ”Large Deformation Finite Element Analysis of Micropipette Aspiratipn to Determine the Mechanical Properties of the Chondrocyte” by F.P.T. Baaijens et al.

The second article describes simplified approach to the problem of load application (which I would also advise, at least for the beginning). They simply partition the face of the sphere and apply suction pressure to the small face which is initially already inside the pipe.

RE: Pressure load definition in Abaqus Explicit when the surface is constantly changing

(OP)
Thanks for the answer,

I saw both the articles which you attached I found that in both the models they are using fluid to load the cell. I am doing 3D modeling. In which I am using hyperelastic incompressible solid. I don't want to use the fluid to load the cell because it will further complicate my analysis. Do you have any other ideas for the micropipette Aspiration of single-cell without using fluid in Abaqus Explicit?


RE: Pressure load definition in Abaqus Explicit when the surface is constantly changing

Actually I was thinking about something like this (suction pressure applied to the red part of the sphere):



It should eliminate the need for variable loaded surface.

RE: Pressure load definition in Abaqus Explicit when the surface is constantly changing

(OP)
Thanks for your answer,

Yes, it is great if you could tell me how to apply the load without using the fluid in Abaqus Explicit, as shown in the above figure.

RE: Pressure load definition in Abaqus Explicit when the surface is constantly changing

Fluid is not necessary here, pressure applied directly to the sphere in the outward direction can pull it towards the tube (it should work well in vacuum too, just leave the motion of the sphere in this direction free). Since it is applied only on the small region of the sphere, there will be no problem with variable area of load application during the aspiration process. You can try with prescribed displacement too.

RE: Pressure load definition in Abaqus Explicit when the surface is constantly changing

(OP)
Hello,

For the above problem, I am interested in solving by applying the pressure load on the backside of the spherical cell. I am planning to solve using VDLOAD user Subroutine. Can anyone help me with the easiest way of doing using VDLAOD?

Thanks

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! Already a Member? Login


Resources

eBook - Rethink Your PLM
A lot has changed since the 90s. You don't surf the Web using dial-up anymore, so why are you still using a legacy PLM solution that's blocking your ability to innovate? To develop and launch products today, you need a flexible, cloud-based PLM, not a solution that's stuck in the past. Download Now
White Paper - Using Virtualization for IVI and AUTOSAR Consolidation on an ECU
Current approaches used to tackle the complexities of a vehicle’s electrical and electronics (E/E) architecture are both cost prohibitive and lacking in performance. Utilizing virtualization in automotive software architecture provides a better approach. This can be achieved by encapsulating different heterogeneous automotive platforms inside virtual machines running on the same hardware. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close