November 16, 2021 at 9:48 pmdestroySubscriber
I am trying to model 2D fluid-structure interaction of two flaps undergoing large deformation due to flowing water.
The flaps are close to eachother. I want to block some of their deformation, telling ANSYS Mechanical to not deform the body if the distance between the bodies is lower than 0.3 mm. This is done to maintain some gap for the flowing water in Fluent.
To do that, I set the frictional contact, and I added a contact offset equal 8e-4 m - where the minimum distance between the flaps at the beginning of simulation is equal about 12e-4 m.
however, it does not help - during the calculations I achieved the minimum distance between flaps equal about 2e-4 m, till the solution diverges due to excessive element distortion. I expected, that I will achieve minimum distance about defined 8e-4.
Do you have any idea why this happens? Maybe I define a distance in a wrong way...
I attatched an image showing the initial minimum distance between flaps
DestroyNovember 16, 2021 at 9:56 pmpeteroznewmanSubscriberUse a negative value of offset to leave a gap between the contact and target surfaces of a frictional contact when the contact elements are in the closed state.
November 16, 2021 at 9:58 pmdestroySubscriberHello again Just after posting I got two ideas:
1) Maybe I should use two times lower offset value, then the gap that I need? I mean, for example if I need a minimum gap equal 8e-4 m, maybe I shoud use offset 4e-4 m? This presumption I made, because maybe Mechanical adds two offsets, first for the Contact and second for the Target? And therefore I should use two times lower value than demanded gap?
2) I just read in Mechanical users guide:
"Offset: appears if Interface Treatment is set to Add Offset, Ramped or Add Offset, No Ramping.This property defines the contact offset value. A positive value moves the contact closer together (increase penetration/reduce gap) and a negative value moves the contact further apart."
So maybe I should use a negative value?
I added pictures of refreshed contact settings
Edit: @peteroznewman thank you for the answer, I posted before I read your message. Could you please verify and answer questions in my second post?
May 12, 2022 at 4:35 amwwzSubscriberHELLO:
i have the same problem with you. I have a film and a rigid body in the flow . the film will contact with the rigid body, so the mesh in the fluent will be negtive volume. I want to know if you solve the problems. thank you so much
Viewing 3 reply threads
Ansys Innovation Space
- The topic ‘Mechanical contact offset’ is closed to new replies.
Boost Ansys Fluent Simulations with AWS
Computational Fluid Dynamics (CFD) helps engineers design products in which the flow of fluid components is a significant challenge. These different use cases often require large complex models to solve on a traditional workstation. Click here to join this event to learn how to leverage Ansys Fluids on the cloud, thanks to Ansys Gateway powered by AWS.
Earth Rescue – An Ansys Online Series
The climate crisis is here. But so is the human ingenuity to fight it. Earth Rescue reveals what visionary companies are doing today to engineer radical new ideas in the fight against climate change. Click here to watch the first episode.
Subscribe to the Ansys Blog to get great new content about the power of simulation delivered right to your email on a weekly basis. With content from Ansys experts, partners and customers you will learn about product development advances, thought leadership and trends and tips to better use Ansys tools. Sign up here.Trending discussions
- How to do the frequency response of the nonlinear vibration of a flexible PCB?
- Importing Line and Solid Bodies from SpaceClaim to Mechanical
- how to open SendCommand in Ansys
- problems facing during solution
- Still facing the same issue
- Failed to move file from solver directory to scratch directory: file.rst
- Adaptive Sizing
- Stiffness factor
- Import DAT file
- Import pressure data (coordinates and value) to ansys workbench through excel
Top Rated Tags
© 2023 Copyright ANSYS, Inc. All rights reserved.Ansys does not support the usage of unauthorized Ansys software. Please visit www.ansys.com to obtain an official distribution.