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support@mecway.com
Mecway
FEA
Bolted Joint Representation
Hey all,
Pretty new to Mecway, coming from a NASTRAN/ANSYS background.
How do you all go about representing bolts in large models? It obviously isn’t reasonable to model every bolt into some things. In NASTRAN, ANSYS or ABAQUS I would just use bush elements to do this. I’m assuming mecway doesn’t support this? I had the thought of using beam elements between two rigids on a hole, but it appears that rigids aren’t really supported in Mecway either.
I saw another discussion where some people is use beam elements for the shank of the bolt, and shells for the head/nut with bonded contact between the surfaces. Ideally, I just want something to hold parts together such that I can back out fastener loads for hand calcs.
TLDR;
1. How do you all represent bolted connections in Mecway?
2. Can I extract axial and shear loads from beam elements?
Input on how you all do this would be much appreciated!
Pretty new to Mecway, coming from a NASTRAN/ANSYS background.
How do you all go about representing bolts in large models? It obviously isn’t reasonable to model every bolt into some things. In NASTRAN, ANSYS or ABAQUS I would just use bush elements to do this. I’m assuming mecway doesn’t support this? I had the thought of using beam elements between two rigids on a hole, but it appears that rigids aren’t really supported in Mecway either.
I saw another discussion where some people is use beam elements for the shank of the bolt, and shells for the head/nut with bonded contact between the surfaces. Ideally, I just want something to hold parts together such that I can back out fastener loads for hand calcs.
TLDR;
1. How do you all represent bolted connections in Mecway?
2. Can I extract axial and shear loads from beam elements?
Input on how you all do this would be much appreciated!
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Comments
You have another option in which the bolts are fully beam elements. The internal protrusion of the nut is used as contact area. There is a liml file in there:
https://mecway.com/forum/discussion/comment/6057/#Comment_6057
Not sure how it would perform in a big model with large number of bolts. I would recommend you to be sure you manage to make one of them to work before running the full model and find that nothing works. There is one contact for each nut with its facing plate and another for the plates themselves. You can introduce nonlinear materials and nonlinear geometric effect if needed.
Regards
NOTE: There is also some sort of RBE3 we have being recently experimenting with an API to easily apply it if you want to try.
https://mecway.com/forum/discussion/comment/6099/#Comment_6099
I have tried using the beam option to model the bolts on a larger scale problem. 20 sets of two plates bolted with 32 bolts each one and loaded in different loading conditions. The model contains 640 thermally preestresed bolts and took 7 minutes to compute. I think small to medium scale structures could be addressed. The holes on the plates consumed a lot of nodes, so I have removed them. If one just wants to extract the axial and shear stress on the bolts I think it could be an option to reduce the computational time. ¿Does someone see any possible problem with this approach?