about Arc-Length Method

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Xiang Wang
Posts: 1
Joined: Thu Jan 24, 2008 10:08 am
Location: UCSD

about Arc-Length Method

Post by Xiang Wang »

Hi, silvia,

I've just conducted a nonlinear fiber section analysis, in order to test for the Arc-Length Integrator.

Compared with the results by Displacement Integrator, two curves fits well in the ascending branch... but in the descending branch, the curve with Arc-Length flip-flops, as the one with Displacement Integrator runs smoothly...I think that the differences may be contribute to the selection method in arc-length method...so, what's the selection criterion for the two roots in arc-length method? and can arc-length method be used to control the direction of displacement increment??

BTW: is there any preconditioning method in OpenSees when the condition number of the stiffness matrix becomes very large??
BLJ
Posts: 5
Joined: Wed Mar 03, 2010 12:22 pm

Re: about Arc-Length Method

Post by BLJ »

Hello,

Can you post your tcl files? I also want to see the difference. Thank you very much.



[quote="Xiang Wang"]Hi, silvia,

I've just conducted a nonlinear fiber section analysis, in order to test for the Arc-Length Integrator.

Compared with the results by Displacement Integrator, two curves fits well in the ascending branch... but in the descending branch, the curve with Arc-Length flip-flops, as the one with Displacement Integrator runs smoothly...I think that the differences may be contribute to the selection method in arc-length method...so, what's the selection criterion for the two roots in arc-length method? and can arc-length method be used to control the direction of displacement increment??

BTW: is there any preconditioning method in OpenSees when the condition number of the stiffness matrix becomes very large??[/quote]
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