Elements failed to get compatible element forces & deformations in time history analysis

[mahipal]

Hi
I am analyzing a 4-story 2D RC frame under gravity followed by earthquake ground motion. All the columns as well the beams have same cross-section. However, I am getting "WARNING - ForceBeamColumn2d::update - failed to get compatible element forces & deformations for element: 2232(dW: << 0.201805)" for the beams of first story only. Is there some problem with the fibre section and element (nonlinearBeamColumn) I defined? Kindly help.

The time history code segment is as follows:
# Define time history load case
set Nsteps 3000
set DtAnalysis 0.01
set TmaxAnalysis [expr $Nsteps*$DtAnalysis];
set G 9.81
timeSeries Path 2 -dt 0.005 -filePath Northridge.tcl -factor $G; # define acceleration vector from file (dt=0.005 is associated with the input file gm)
pattern UniformExcitation 2 1 -accel 2; # define where and how (pattern tag, dof) acceleration is applied

# set damping based on first eigen mode
set zeta 0.05; # percentage of critical damping
set betaK [expr $zeta*2.0/($w1)]; # stiffness proportinal damping coefficient
rayleigh 0.0 0.0 0.0 $betaK ;# last committed stiffness is actually just the element’s tangent stiffness

constraints Transformation ; #Lagrange
numberer RCM ;
system UmfPack;#SparseGeneral;BandSPD;UmfPack ;BandGeneral
set Tol 1.e-8;
variable testTypeDynamic EnergyIncr;
test EnergyIncr $Tol 10;
algorithm Newton;# Newton-Raphson algorithm to solve the nonlinear residual equation

integrator Newmark 0.5 0.25 ;
analysis Transient ;
# analyze 3995 0.01;

set ok [analyze $Nsteps $DtAnalysis]; # apply 3995 0.01-sec time steps in analysis
if {$ok != 0} { ; # analysis was not successful.
set ok 0;
set controlTime [getTime];
while {$controlTime < $TmaxAnalysis && $ok == 0} {
set controlTime [getTime]
set ok [analyze 1 $DtAnalysis]
if {$ok != 0} {
puts "Trying Newton with Initial Tangent .."
test NormDispIncr $Tol 1000
algorithm Newton -initial
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
if {$ok != 0} {
puts "Trying Broyden .."
algorithm Broyden 10
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
if {$ok != 0} {
puts "Trying NewtonWithLineSearch .."
algorithm NewtonLineSearch 0.8; #0.8 is default tol
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
if {$ok != 0} {
puts "Trying NewtonWithLineSearch .."
algorithm ModifiedNewton
set ok [analyze 1 $DtAnalysis]
test EnergyIncr $Tol 10
algorithm Newton
}
}
};

[mhscott]

You probably have an error in your section definition, or you have loaded the model beyond its limit. Do a moment-curvature analysis and other checks to figure out the issue.

https://portwooddigital.com/2021/10/10/ ... ompatible/