How to alter the .bdf to change contact settings from Glued to touching.

Hello, I have an assembly with 4 parts, and I need to swap 2 of the 3 contact settings from glued to touching with a friction coefficient of 0.05. Bodies 1, 2 , and 3 should be touching, while bodies 3 and 4 should be glued. I'm looking through the nastran reference guide, but interpreting the matrices within matrices is proving difficult.

Thanks for any help!

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0 Don.Graff over 3 years ago

BCONECT 3 is what 'connects' bodies 3 and 4, so leave that one alone, and remove the 'glue' settings (IGLUE 2) from the other 2 BCONECT entries:
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0 Don.Graff over 3 years ago
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0 Don.Graff over 3 years ago

once you feel this is working as desired, then you can add friction by defining the FTYPE (usually 6 for bi-linear coulomb) on the BCPARA entry and then a friction coefficient on the BCONPRP (FRIC field)... you call out the BCONPRP on the fourth field of the BCONECT entry.
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0 elijah.d.lamppin.civ over 3 years ago

Well, I thought I had it right but there's some problems found in the .f06. Attached are the .f06 and the .bdf sections for this.

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0 elijah.d.lamppin.civ over 3 years ago

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0 Don.Graff over 3 years ago

you need to shift the FRIC entry one more field to the right... the 3rd field is always blank... it is easier to use free field format if hand-editing:

BCONPRP, PID, , FRIC, 0.02
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0 Don.Graff over 3 years ago

also, you will need to add the BCONPRP entry ID to the BCONECT field 4 or it won't be turned on.

BCONECT, ID, BCGPID, BCPPID

Your best approach is to do all this on a simple samplemodel, and if you have issues getting it to work, it is best to open a support case with MSC Technical Support... it is sometimes more difficult to communicate at a detailed level via the forum.
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0 elijah.d.lamppin.civ over 3 years ago

Thank you!!! I have it working now. The big thing that made it all start clicking was mentioning I can use "tree field format" which I've never heard of before. That made it so much easier to conceptualize and follow the manual with.
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