ForceBeamColumn3d::update - failed to get compatible

[danile]

hi all!

i'm performing a dynamic analysis on a 3d rc frame building (column in z-direction and beam in x direction and in y direction).
i've a question: when i do the dynamic analysis opensees says to me:
"
WARNING - ForceBeamColumn3d::update - failed to get compatible element forces &
deformations for element: 631632(dW: << -1.#IND, dW0: -1.#IND)
"

however the analysis finishes.

BUT when i see the output files i have some problem:
for all the beam in y direction the early numbers of globalForce are 0: in the gravity load and the first 5 steps of dynamic analysis. here down an exlemple:

"
0.1 0 0 0 0 0 0 0 0 0 0 0 0
0.2 0 0 0 0 0 0 0 0 0 0 0 0
0.3 0 0 0 0 0 0 0 0 0 0 0 0
0.4 0 0 0 0 0 0 0 0 0 0 0 0
0.5 0 0 0 0 0 0 0 0 0 0 0 0
0.6 0 0 0 0 0 0 0 0 0 0 0 0
0.7 0 0 0 0 0 0 0 0 0 0 0 0
0.8 0 0 0 0 0 0 0 0 0 0 0 0
0.9 0 0 0 0 0 0 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0 0 0 0
1.005 0 0 0 0 0 0 0 0 0 0 0 0
1.01 0 0 0 0 0 0 0 0 0 0 0 0
1.015 0 0 0 0 0 0 0 0 0 0 0 0
1.02 0 0 0 0 0 0 0 0 0 0 0 0
1.025 0 0 0 0 0 0 0 0 0 0 0 0
1.03 5.41925e-013 1.67556e-005 -9.95609e-007 ...
1.035 2.80703e-013 0.000309928 -1.33727e-005 ...
1.04 -1.11132e-013 0.000736775 -3.02088e-005 ...
1.045 -2.09245e-013 0.000945273 -3.1909e-005 ...
1.05 -1.96513e-014 0.000948282 -1.82314e-005 ...
1.055 -9.05018e-014 0.000829156 4.20445e-006 ...
1.06 5.61949e-015 0.00100933 3.83455e-005 -0.00378668 ...
1.065 -3.61881e-014 0.00144633 8.26141e-005 0.116913 ...
1.07 -1.5091e-013 0.00208004 0.000134358 0.256592 ...
etc..."
(the ... means that the output is logher and i eliminated in the mail some element for convenience )

what's the problem? i's linked to the model?

NOTE: this problem is when i loaded the nodes. after i tried loading the beam in x direction and pratically i have the same result. instead when i load the beam in y direction i don't have this problem... it's possible that the problem is because the beam in y direction isn't enought stressed, and only after the stress became evdent? ( i'm not very convinced about that!)

thx!!!

danile

[silvia]

try:
1. compare to examples manual
2. run eigen analysis after defining your masses.

[danile]

hi silvia

thx for your fast reply!

1- really i don't see difference from examples manual's scipts ( i compare my model with the exemple 7).

2- for the eigen analysis, i think that there are no problem: i have a 6 floor building, and the periods are:

T1=1.1383124975173782
T2=0.8036370348873173
T3=0.7686173162448388
T4=0.35901854698491165
T5=0.2492623084073496
T6=0.24096253288188613

i think that is ok.

it's possible that there are some mistake when i set the BeamTransfTag???

ALSO: i try with a simple building (8 node) and the load in the node. At first i try with elastic beam and column: i have no problem. After i use the fiber sections: the problem persists. i have to think that the problem is related to the fiber definition, isn't it?



thank you!

[silvia]

it may be that the demands on the section/element are really high.
still, try doing a moment-curavature analysis on your section to check it, it may be a bad section -- make sure you have a realistic axial load.

have you looked at BuildingTcl?

[danile]

hi silvia!

probably i found the error: it's linked with torsional stiffness. i make a mistake when i place it into the model. now i'll try with default torsional stiffness and i hope it's all ok. after i'll say to you if it's ok.

no, i didn't still look at BuildingTcl.

thx!

hear you soon

[danile]

hi silvia!

1) i tried with a simple 8-nodes moldel without torsional stiffness --> OK (and before i have problem also with simple 8-nodes moldel for beam in y direction).

2) after i eliminated torsional stiffness in my model: i removed section aggregator command ---> the result from eigen analysis is very similar ( i have a default GJ = 1e10). but the problem with beam in y direction persists...

3) last mail you told me that "it may be that the demands on the section/element are really high", but what it means? i isn't enough doing the section bigger? for instance from 35x55 to 35x65 cm? i tried that but the error remain. ( do i understand good???)

4) and also the problem remain when i use the elastic beam column in the model...


i have no idea, i don't know where and how i can do... and the strange thing is that now the simple model run withiout problem!

what can i do?

thx

[silvia]

please email me your model: opensees-support at berkeley dot edu

[silvia]

Daniele,
i had no problem running your model, i am confused!

[danile]

yes, me to!

ok, at first sight it seems ok. but if you look the recordere element, for istance @FORZEtraviY_1112.out, you can see that all the force are 0!