fbd_inv

[paky983]

hello, i have 2 question about convergence of a general analysis:
1)what does "fbd_inv" means, in the running analysis?
2)which parameter should be changed to not have the fbd_inv ?

[seismosoft]

Have you tried searching the Help System and/or this Forum for the word "fbd_inv"? You should.

Seismosoft Support

[ladex]

I have the same problem.
I found with this search
http://www.seismosoft.com/forum/search.asp?mode=DoIt

I put the convergence criteria 0.1 mm 0,0001 rad
and 1000 iterations does not change anything:
here is the analysis

Code: Select all

      Permanent Loading
-----------------------------------------

 LF=  0.00000,   LF_incr=           (Iter:  3 => fbd_Inv)
 LF=  0.12500,   LF_incr=  0.12500  (Iter:  3 => Converg)
 LF=  0.37500,   LF_incr=  0.25000  (Iter: 10 => Converg)
 LF=  0.37500,   LF_incr=           (Iter:  3 => fbd_Inv)
 LF=  0.43750,   LF_incr=  0.06250  (Iter:  6 => Converg)
 LF=  0.56250,   LF_incr=  0.12500  (Iter: 16 => Converg)
 LF=  0.56250,   LF_incr=           (Iter:  3 => fbd_Inv)
 LF=  0.59375,   LF_incr=  0.03125  (Iter: 10 => Converg)
 LF=  0.65625,   LF_incr=  0.06250  (Iter: 40 => Converg)
 LF=  0.65625,   LF_incr=           (Iter:  3 => fbd_Inv)
 LF=  0.67188,   LF_incr=  0.01563  (Iter: 27 => Converg)
 LF=  0.70313,   LF_incr=  0.03125  (Iter:178 => Converg)
 LF=  0.70313,   LF_incr=           (Iter:  3 => fbd_Inv)
 LF=  0.70313,   LF_incr=           (Iter:376 => fbd_Inv)
-----------------------------------------
Unable to apply the entire permanent load. Analysis terminated
    Total Analysis Time: 0h:10min:29sec

recommendations?
sorry for my english

[seismosoft]

Dear ladex,

There could be many different reasons for the convergence difficulties that you report, though in the majority of times these are related to either errors in the model (e.g. disconnected elements) or excessive loading.

We suggest you to search this Forum for “convergence problems” and follow at least some of the multiple suggestions that you will find.

Seismosoft Support

[ladex]

solved using linear material

bye