×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Modelling a rope in Solidworks 2006/ 2007

Modelling a rope in Solidworks 2006/ 2007

Modelling a rope in Solidworks 2006/ 2007

(OP)
I am trying to model a braided rope in Solidworks. Can anyone advise me on how to do this. I have tried many things and have been unsuccesful. If anyone has any suggestions please let me know.

Thank you!!

RE: Modelling a rope in Solidworks 2006/ 2007

dudeSW,

   Is the rope straight, or does it hang between its ends.  A straight rope would be a couple of helices, with the circle sections overlapping a bit.

   I heard somewhere that ropes and chains hang in a hyperbolic cosine.  Modeling this with helices will be fun!

                      JHG

RE: Modelling a rope in Solidworks 2006/ 2007

Just how accurate do you need to model it?  A sweep with twist of the rope cross section along a 3D sketch should give you excellent visual results.  Making it move like a rope in an animation will be more problematic, but there are a lot of experts here who can help you with that.

Timelord

RE: Modelling a rope in Solidworks 2006/ 2007

(OP)
Thank you drawoh and timelord for your responses.  I think I did not explain myself well.  I need to model more of a braid.  So the individual strands have to interweave.  I am having trouble with the weave.  Please suggest if you can.  Thank you again!!!

 

RE: Modelling a rope in Solidworks 2006/ 2007

(OP)
Also, I need to model it accurately as I would like to preform an FEA analysis on the model in compression.

RE: Modelling a rope in Solidworks 2006/ 2007

In SW 2007 you can also use the Flex command.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog

RE: Modelling a rope in Solidworks 2006/ 2007

(OP)
ctopher,

can you explain how i can create a weave with multiple strands with the flex command?  This was one of my attemps earlier that was unsuccessful.  I also tried projecting a profile on a curved surface.  Is there a way to how a helix follow a guided curve?  Would this work?

Thank you!

RE: Modelling a rope in Solidworks 2006/ 2007

dudeSW,

   You are going to have to search a manual or the internet for whatever rope braid you are using.  Perhaps a boy scout manual or an outdoor survival book will tell you something.  There are many ways to braid ropes.  

   There are ways to fake geometry like this, but not if you are doing FEA.  

                         JHG

RE: Modelling a rope in Solidworks 2006/ 2007

Compression?

"Art without engineering is dreaming; Engineering without art is calculating."

Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of these Forums?

RE: Modelling a rope in Solidworks 2006/ 2007

Create a sketch with the strands where you want them, then extrude it to the required distance...plus a little more.
Use the flex command to twist the extrusion as needed, then add bends via the flex command.
I have created braided wire like this. It takes a little practice, but works.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog

RE: Modelling a rope in Solidworks 2006/ 2007

(OP)
Thank you for the example.  The rope, (braid) i need to make is somewhate more complex.  I need the strands to weave together like a basket.  The basic way to think about it is like the braid in someone's hair.  The model will be a basket like weave with no bottom to the basket.

RE: Modelling a rope in Solidworks 2006/ 2007

Can be done with pratice. Or as the other's suggested, a 3D sketch with a sweep. YouTube may have some examples.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog

RE: Modelling a rope in Solidworks 2006/ 2007

Modelling it will be a pain.

You mention FEA. If this is the primary aim, could a bit of lateral thinking create a really simple model to test. i.e. multiply up the strands?

I must confess I know as much about FEA as the first chapter of the Cosmos Works Designer manual, so this might be completely rubbish advice.

Regards

WP
www.whitney-paine.com

RE: Modelling a rope in Solidworks 2006/ 2007

Quote:

Compression?

MadMango,

   That occurred to me too.  I figure you can push a rope if it is short enough, but maybe then you should not consider it a rope.  See thread1103-224665: Bolts vs Screws for what happens when a semantics discussion gets out of control.  :)

   I do not see how any analysis is going to work here without a precisely accurate model of the braid.  No handy dandy visual trick is going to work here.

   Is this a metal or plastic rope, or is it a rope made of some grossly non-homogenous material like what ropes are traditionally made of?

                        JHG

RE: Modelling a rope in Solidworks 2006/ 2007

(OP)
DraftingMan ,

That is exactly what I am trying to model!!

Any suggestions anyone?

Thank you!

RE: Modelling a rope in Solidworks 2006/ 2007

I wouldn't bother modeling it. It would be a headache, take a lot of your time to figure it out, then model it. FEA will take longer and possibly crash.
I would create a basic model close to it, then apply appropriate materials to it.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog

RE: Modelling a rope in Solidworks 2006/ 2007

(OP)
Sorry, I used rope for lack of another term.  Semantics, an impartant factor in communication.  :)

You are correct that an analysis won't work without a precisely accurate model.  This is why I am inquiring about methods to develop a model.

The material is metal, I have all the values I need in order to run an analysis, i just need to develop the model.

RE: Modelling a rope in Solidworks 2006/ 2007

If it's a cable or wiring, or ?? ... model it, then model a 'shell' over it. Add the correct metal to the 'shell'.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog

RE: Modelling a rope in Solidworks 2006/ 2007

Regardless of if you could accurately model an object like that one, could you trust the results of a FEA analysis of it.

The actual response of that material to a load will depend a lot on factors which will be hard to capture in an FEA program.  Specifically the wires may or may not slide against one another depending on friction and the applied load.  Additionally there could be significant change in the orientation / configuration of the strands with respect to the load.

You may have more success experimentally determining the behavior of the rope and applying appropriate material properties to a geometrically simpler shape for further analysis.

Eric
 

RE: Modelling a rope in Solidworks 2006/ 2007

Quote (EEnd):

Regardless of if you could accurately model an object like that one, could you trust the results of a FEA analysis of it.

The actual response of that material to a load will depend a lot on factors which will be hard to capture in an FEA program.  Specifically the wires may or may not slide against one another depending on friction and the applied load.  Additionally there could be significant change in the orientation / configuration of the strands with respect to the load.

You may have more success experimentally determining the behavior of the rope and applying appropriate material properties to a geometrically simpler shape for further analysis.

I agree 1-million % with EEnd.  You are way better off performing some real world tests.

-Dustin
Professional Engineer
Certified SolidWorks Professional
Certified COSMOSWorks Designer Specialist

RE: Modelling a rope in Solidworks 2006/ 2007

(OP)
Regardless, I am still interested in trying to figure out how to model something like this.  I appreciate all the responses but still welcome suggestions on how to accurately model something like this.  

Thank you.

RE: Modelling a rope in Solidworks 2006/ 2007

All of the above suggestions...and practice.

Chris
SolidWorks/PDMWorks 08 3.1
AutoCAD 06/08
ctopher's home (updated Jul 13, 2008)
ctopher's blog

RE: Modelling a rope in Solidworks 2006/ 2007

Model rope? Fraid not.
"found at the end"

--
Hardie "Crashj" Johnson
SW 2008 SP4
Nvidia Quadro FX 1000
AMD Athalon 1.8 GHz 2 Gig RAM

 

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources