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Member
ryannechapman
Posts: 4
Registered: ‎02-26-2013

Non Linear hinge: Number associated with them

222 Views, 5 Replies
02-26-2013 03:02 PM

HI,

 

I ran a non linear model on a 2D frame, and gradually added non-linear moment hinges on the members near the points of highest stress to simulated the collapse from plastic hinges. 

 

The highest global stress is given as a bar and a node location, so I had to add non-linear hinges on the bar at a relative distance that was close to the node but not on the node itself. 

 

When I got my structure to become unstable it gave the error message of "instability (of tyoe 3) at node 32 in direction Ry"  I tried to find out which location this instability occured so I had the program display the number of calculation points and it shows 2 different numnbers at each hinge and I cannot find a pattern to the numbering. Also, the numbers are as low as 3 and as high as 90 but not all of the numbers in between these two are on the screen. 

 

Can anyone tell me how the numbering works for non-linear hinges and what the instability at node 32 means. 

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Rafal.Gaweda
Posts: 4,935
Registered: ‎04-26-2010

Re: Non Linear hinge: Number associated with them

02-27-2013 12:40 AM in reply to: ryannechapman

Send us model to look at.



Rafal Gaweda
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Member
ryannechapman
Posts: 4
Registered: ‎02-26-2013

Re: Non Linear hinge: Number associated with them

02-27-2013 08:05 AM in reply to: ryannechapman

It will not let me uplaod an Autodesk file. Would you like a screen shot or do you need to file?

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Rafal.Gaweda
Posts: 4,935
Registered: ‎04-26-2010

Re: Non Linear hinge: Number associated with them

02-27-2013 08:15 AM in reply to: ryannechapman

Zip file before attaching.

If it is bigger than 1.5 MB please used www.filemail.com or www.wetranster.com or any other similar  to generate link to file then post the link here.



Rafal Gaweda
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Member
ryannechapman
Posts: 4
Registered: ‎02-26-2013

Re: Non Linear hinge: Number associated with them

02-27-2013 08:43 AM in reply to: Rafal.Gaweda

Attached is the zip file 

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Product Support
Rafal.Gaweda
Posts: 4,935
Registered: ‎04-26-2010

Re: Non Linear hinge: Number associated with them

02-28-2013 03:52 AM in reply to: ryannechapman

1. Ful Newton Raphson should be set for these cases:

 

nr.jpg

 

2. Define properly nonlinear function, try to avoid relative definition of limits.

My example below

 

hinge2.jpg

 

 

3. or delete hinges from bottom of the columns.



Rafal Gaweda
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