Dear all,
I modeled a cantilever column with a concentrated mass at its top as 2dof structure. Picture below shows schematic of structure:

The code to model the system is as follow:
#to model a cantilever steel column
#units [length: cm], [force: kgf]
wipe
source box.txt; #procedure to model steel box sections
model BasicBuilder -ndm 3 -ndf 6
node 1 0 0 0
node 2 0 300 0
fix 1 1 1 1 1 1 1
fix 2 0 0 0 0 0 0
mass 2 20 1e-9 20 0 0 0; #assign seismic mass to dof’s 1 & 2
set matID 1
uniaxialMaterial Steel01 $matID 2400 2.1E6 0.02
set coltag 1
box $coltag $matID 20 1; #steel box section of width 20cm and thickness 1cm
geomTransf PDelta 1 0 0 1
element nonlinearBeamColumn 1 1 2 5 1 1
eigen 2; #calculate eigenvalues
I am trying to calculate 2 eigenvalues but I faced to this error:
ArpackSolver::Error with _saupd info = -9999
Could not build an Arnoldi factorization.IPARAM(5) the size of the current Arnoldi factorization: is 3factorization. The user is advised to check thatenough workspace and array storage has been allocated.
WARNING DirectIntegrationAnalysis::eigen() – EigenSOE failed in solve()
Do you know where the problem is?
I would appreciate it if you give consideration to this request.