Solving ANSYS Contact Problem for FEA of Rail Fastening Systems

In summary, you should use "augmented lagrange" for contact conditions, and "automatic bisection" to keep the updates consistent. You'll also want a lot of substeps to account for the inaccuracies in your CAD data.
  • #1
albertop
2
0
I'm currently writing my thesis on a "Finite Element Analysis of rail fastening systems under dynamic load", and I'm using ANSYS Workbench 14.0 for that matter.

I don't know how to define the contact area for the clip and the angle guide plate, since it will be changing over time as the clip (and the plate) deform due to the loads applied.
http://imgur.com/xbLPbOl
http://imgur.com/eVhZB6G

This picture shows the existing gap between them, for you to see the future contact areas:
http://imgur.com/YdmPnxy

The CAD data for both objects were obtained with a 3D scanner, which means that the surfaces are neither smooth nor perfectly fitting to each other.

I'm too experienced with ANSYS; therefore a thorough answer will be greatly appreciated!

Thank you in advance!
 
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  • #2
There is a lot to consider, you'll have to get into the gritty details of the contact conditions if you hope to defend the thesis. From a high level, the main considerations you should address from what I'm seeing:

  • You should clean up your mesh by inserting a "Method" object in the mesh portion of the problem tree, and select "hex dominant." This will give you a quad-primary mesh. You're also going to want a much denser mesh than what you have right now.
  • I would select frictionless contact conditions for a start, and then add friction as you have a reliably converging problem setup. Make sure you select your coefficient of friction carefully though, it can vary wildly with subtle changes in material and surface finish.
  • Select "augmented lagrange" for your contact condition formulation, make sure the contacts update every substep, and have "automatic bisection" active.
  • Make sure you have similarly sized elements on both sides of the contact condition using a "contact sizing" mesh element.
  • Substeps: you'll want a lot of them. Possibly hundreds.

That should give you a good start anyway.
 
  • #3
Hello Mech_Engineer,

Yes, it's kind of a hard project considering I'm pretty new to ANSYS.

Thanks for the advice, I really appreciate it!
 
  • #4
Ansys 14.5 contact setting help

Hello to all ,
I new to ansys workbench and I am need guidance as to how to do contact settings and how to find the friction between two moving surfaces. Im designing a surgical scissor. Kindly let me know what settings are preferable for contact setting of scissor and how to find friction between surfaces.

thanks for taking time and helping me.
 

1. How can I ensure that my ANSYS contact problem for FEA of rail fastening systems is accurate?

To ensure accuracy in your ANSYS contact problem for FEA of rail fastening systems, it is important to have a thorough understanding of the contact types and contact settings available in ANSYS. You should also carefully mesh your model to capture the contact surfaces and their behavior accurately. Additionally, performing convergence studies and validating your results against experimental data can help ensure accuracy.

2. What are the different types of contacts available in ANSYS for modeling rail fastening systems?

ANSYS offers several types of contact elements for modeling rail fastening systems, including bonded, frictional, and rough surface contacts. Bonded contacts assume perfect adhesion between contact surfaces, while frictional contacts allow for sliding and separation between surfaces. Rough surface contacts are useful for modeling situations where surfaces are not perfectly smooth.

3. How can I troubleshoot contact issues in my ANSYS FEA model of rail fastening systems?

If you are experiencing contact issues in your ANSYS FEA model of rail fastening systems, there are several steps you can take to troubleshoot the problem. First, check that all contact surfaces are properly defined and have appropriate contact types and settings. You should also ensure that your model is properly meshed and that the contact surfaces are close enough to interact. If the issue persists, try adjusting the contact stiffness or increasing the convergence criteria.

4. Can I use ANSYS contact elements for modeling nonlinear behavior in rail fastening systems?

Yes, ANSYS contact elements can be used to model nonlinear behavior in rail fastening systems. The frictional and rough surface contacts allow for sliding and separation between surfaces, which can capture nonlinear behavior such as plastic deformation and material damage. However, it is important to carefully calibrate the contact parameters and validate the results against experimental data to ensure accuracy.

5. Are there any best practices for modeling contact in ANSYS for rail fastening systems?

Yes, there are several best practices for modeling contact in ANSYS for rail fastening systems. These include carefully defining contact surfaces, using appropriate contact settings and types, and performing convergence studies to ensure accuracy. It is also important to validate the results against experimental data and to use caution when interpreting the results, as contact behavior can be complex and sensitive to small changes in parameters.

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