Error in eigenvalue analysis

[hussien]

Hello,

Fairly new to the opensees and stko world. There is a program called MsBridge, i was trying to replicate one of its models in stko to confirm my modeling approach. i did a simple two span bridge with a pier. and tried running an analysis.


and got this error
"OpenSees -- Open System For Earthquake Engineering Simulation
Pacific Earthquake Engineering Research Center
Version 3.7.2 64-Bit

(c) Copyright 1999-2016 The Regents of the University of California
All Rights Reserved
(Copyright and Disclaimer @ http://www.berkeley.edu/OpenSees/copyright.html)


MPCO recorder - Written by ASDEA Software Technology: M.Petracca, G.Camata
ASDEA Software Technology: https://asdeasoft.net
STKO (Scientific ToolKit for OpenSees): https://asdeasoft.net/stko/
If you use this tool, please cite us:
Petracca, M., Candeloro, F., & Camata, G. (2017). "STKO user manual". ASDEA Software Technology, Pescara Italy.
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (6, -9.73243e-58)
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (8, -9.83235e-26)
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (18, -9.73243e-58)
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (20, -9.83235e-26)
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (30, -9.73243e-58)
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (32, -9.83235e-26)
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (42, -9.73243e-58)
ProfileSPDLinDirectSolver::solve() - aii < minDiagTol (i, aii): (44, -9.83235e-26)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (54, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (66, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (69, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (78, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (81, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (90, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (93, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (114, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (117, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (126, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (129, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (138, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (141, 0)
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (150, 0)
ANALYSIS SUCCESSFULLY FINISHED
Press any key to continue . . ."


i have attached the stko file and the msbridge tcl files. what is the issue here, are my equaldof and zerolength materials wrong?

[STKO Team]

That error shows that your model is singular.
I would suggest you follow the basic e-learning corses because you are using the wrong CAD modeling apporach.
STKO is not an orphan-mesh based modeler, so you don't have to model nodes and elements (connectivity) one by one, otherwise they will be detached from eachother (leading to the singularity you see here).

This is the right modeling approach (Note: I added a small gap between the different parts to show their interactions):

Merge Bridge parts.png (42.02 KiB) Viewed 306 times

[hussien]

Thank you! i figured that out and got a model running. I tried to switch up the model a little bit by using more points for the roller abutment model also using MSbridge. and i got the following error
Pacific Earthquake Engineering Research Center
Version 3.7.2 64-Bit

(c) Copyright 1999-2016 The Regents of the University of California
All Rights Reserved
(Copyright and Disclaimer @ http://www.berkeley.edu/OpenSees/copyright.html)


MPCO recorder - Written by ASDEA Software Technology: M.Petracca, G.Camata
ASDEA Software Technology: https://asdeasoft.net
STKO (Scientific ToolKit for OpenSees): https://asdeasoft.net/stko/
If you use this tool, please cite us:
Petracca, M., Candeloro, F., & Camata, G. (2017). "STKO user manual". ASDEA Software Technology, Pescara Italy.
ProfileSPDLinDirectSolver::solve() - aii < 0 (i, aii): (204, 0)
WARNING ModifiedNewton::solveCurrentStep() -the LinearSysOfEqn failed in solve()
StaticAnalysis::analyze() - the Algorithm failed at step: 0 with domain at load factor 0.1
OpenSees > analyze failed, returned: -3 error flag
ERROR: the analysis did not converge
while executing
"error "ERROR: the analysis did not converge""
("for" body line 30)
invoked from within
"for {set STKO_VAR_increment 1} {$STKO_VAR_increment <= $initial_num_incr} {incr STKO_VAR_increment} {

# before analyze
STKO_CALL_OnBeforeAnalyze
..."
(file "analysis_steps.tcl" line 83)
invoked from within
"source analysis_steps.tcl"
(file ".\main.tcl" line 81)
Press any key to continue . . .
The files are zipped in this link.
https://drive.google.com/file/d/1SI0vPM ... Nzj-s/view

is it the fact that Msbridge applies the load in two stages? will that make an effect?

[STKO Team]

I moved again your parts apart and as you can see you have un-connected nodes.
That error means that your model is singular.

unconnected.png (87.12 KiB) Viewed 235 times