Cancel
Showing results for 
Search instead for 
Did you mean: 

How to simulate ropes or chains

Creator
Creator
Hello,

I can't find any possibility in NX6 to create elements or manipulate for simulating ropes or chains. Does anybody know how I can do that in NX6 with NX-Nastran.

Thanks, Maik
NX 7.5.2, NX-Nastran 7.1
7 REPLIES

Re: How to simulate ropes or chains

Siemens Builder Siemens Builder
Siemens Builder
In the Advanced nonlinear solutions, you could use rod elements with a nonlinear elastic material (MATS1 with TYPE=NLELAST).

In SOL 106, you could use PBUSHT type KN.

In SOL 101, you could use gap elements set up as 'hooks'. Be sure to toggle on the 'Treat CGAP as Linear Contact Elements' toggle on the edit solution form in NX.
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm

Re: How to simulate ropes or chains

Creator
Creator
Hello Jim,

thanks for the reply and help. I will give it a try.

Thanks, Maik
NX 7.5.2, NX-Nastran 7.1

Re: How to simulate ropes or chains

Creator
Creator
Hello,

I tried to use the CGAP in SOL101 but I'm not able to get the behavior of a rope. I played hit the contact stiffness, etc. but no success. :confused:

@Jim: Is it possible to give me another tip.

Thanks, Maik
NX 7.5.2, NX-Nastran 7.1

Re: How to simulate ropes or chains

N/A
Gap elements in sol 101 behave just like linear springs. You need to use sol 106 for gaps to have the bilinear behavior.
You can also use the nonlinear elastic material trick for a rod in sol 106.

Re: How to simulate ropes or chains

Siemens Builder Siemens Builder
Siemens Builder
Gap elements in sol 101 behave just like linear springs. You need to use sol 106 for gaps to have the bilinear behavior.
You can also use the nonlinear elastic material trick for a rod in sol 106.


Joe,

This is true in other Nastran versions. However, in NX Nastran, if you add a BCSET card to your case control (and leave system cell 412/OLDGAPS set to it's default of 0) in SOL 101, the CGAP elements will be treated as linear contact elements.

The gap stiffness comes from KA and KT on PGAP by default. System cell 464 can be set to have gap stiffness determined from the linear contact penalty factors.

Regards,
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm

Re: How to simulate ropes or chains

Siemens Builder Siemens Builder
Siemens Builder
Hello,

I tried to use the CGAP in SOL101 but I'm not able to get the behavior of a rope. I played hit the contact stiffness, etc. but no success. :confused:

@Jim: Is it possible to give me another tip.

Thanks, Maik


Here's an example NX database with NX Nastran input decks and output files. There is a SOL 106 and SOL 101 version of the same model using CGAPS. Results are identical. Axial force in the cable/rope is zero in the compression subcase.
--
Jim Bernard
Advanced Applications Engineer

Siemens PLM Software
2000 Eastman Dr., Milford, OH 45150-2712
www.siemens.com/plm

Re: How to simulate ropes or chains

Creator
Creator
Here's an example NX database with NX Nastran input decks and output files. There is a SOL 106 and SOL 101 version of the same model using CGAPS. Results are identical. Axial force in the cable/rope is zero in the compression subcase.


Hello Jim,

thanks for the input decks. My falt was an wrong model(see 1 sketch in PDF). I thought its enough to set the open/close stiffness so that the stiffness for open contact has an high value and for closed stiffness the other way around.

Thanks all for helping, Maik
NX 7.5.2, NX-Nastran 7.1