Dear All,
Has anyone built a model to simulate and check Chain and sprocket for
- Fitment
- Torque/Load transfer
- NVH ( vibration analysis)
I don’t think you can find a ready-made PrePoMax model of this. You could look for some examples in Abaqus since the syntax is in large part the same as the one of CalculiX. But it may not be easy to find such examples either. In fact, mechanisms like that are usually simulated with MBD approach so maybe check the MBDyn add-on for FreeCAD: https://www.youtube.com/@josegegas/videos
Thank you for your feedback. I will check this.
Let me know if the below sprocket can transfer 25Nm( from motor shaft) . Let us not worry about the chain now( for time being). I want to know if our approach to check if the sprocket can handle the above criteria is correct or not…
- ANSI 25 , No of Teeth 17. Thickness of sprocket: 11mm. The model is attached( option 1).
- ANSI 25 , No of Teeth 17. Thickness of sprocket: 11mm. The model is attached ( option 2).
Just the screenshots but I can already see a very likely mistake in the second picture. It’s explained in this post: Don't apply concentrated force load to surfaces
How can I share the model? It is not allowing me to upload files as it is more than specified limit…
you were right. It matches with the correct model.
So we are very sure that the sprocket can transfer 25Nm.
Please confirm.
You could use some hosting website like Dropbox, Google Drive, WeTransfer or other and share the link here.
we can just change the options in the model
- Use momentum
- use surface traction
Please let me know which one is the correct approach…
It’s a highly simplified approach but commonly used in practice to avoid simulating the whole system with the chain. However, you should consider applying the forces to all engaged teeth. Theoretical basics for that can be found in the literature. One example: https://ijera.com/papers/Vol6_issue9/Part-5/M060905066069.pdf
I have read the paper and a few more similar ones. What we have done is very simple after calculating the worst-case torque transfer and the force that acts on the tooth. Further worst case scenario we want to keep 5-6 teeth engaged.
I hope it makes sense?.
Now do you have an example for running analysis on the chain please ?.
Yeah, it’s always good to check the worst case first and be on the safe side. But it’s also very valuable to compare the results from the different approaches (different simplification levels). Here you could do the hand calcs as well (based in the standard machine design handbooks).
Chain alone or together with the sprocket as a mechanism ?
please share both options if u can …
As I’ve mentioned initially, I don’t have any ready examples of sprocket with chain and it can be hard to find them (also because it’s usually simulated with MBD) but there are some for chains themselves:
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Thank you for your update.