NLBUCKLING WITH CALCULIX

Hello

I'm doing a simple nl buckilng with beam elements, a very simple model.

Please, did anyone experience very long still times in solving these tasks with calculix?

Thank you

Bruno

*NODE,NSET=Nall
1, 0, 0, 0
2, 0, 0, 500
3, 0, 0, 1000
4, 0, 500, 1000
5, 0, 1000, 1000
6, 0, 1000, 500
7, 0, 1000, 0

*ELEMENT,TYPE=B32,ELSET=EALL
1,1,2,3
2,3,4,5
3,5,6,7

*BOUNDARY
3,1,6
7,1,6

*MATERIAL,NAME=STEEL
*ELASTIC
2E5,0.3

*PLASTIC,HARDENING=ISOTROPIC
311.753332,0.00000,273.0
332.292332,0.00097,273.0
352.831331,0.00243,273.0
373.370331,0.00456,273.0
393.909330,0.00763,273.0
414.448330,0.01196,273.0
434.987329,0.01795,273.0
455.526329,0.02612,273.0
476.065329,0.03712,273.0
496.604328,0.05173,273.0
517.143328,0.07092,273.0
537.682327,0.09583,273.0
558.221327,0.12786,273.0
578.760326,0.16868,273.0
599.299326,0.22023,273.0
619.838325,0.28483,273.0
640.377325,0.36518,273.0
660.916325,0.46442,273.0
681.455324,0.58619,273.0
701.994324,0.73469,273.0
722.533323,0.91473,273.0

*BEAM SECTION,ELSET=EALL,MATERIAL=STEEL,SECTION=RECT
20
1.d0,0.d0,0.d0

*AMPLITUDE,NAME=Loading
0.,0,1.,1

*TIME POINTS,NAME=T20,GENERATE
0.,1.,0.05

*NSET,NSET=N5
5

*STEP,T20

*STATIC
0.05,1.

*CLOAD, AMPLITUDE=Loading
5,1,5000

*NODE PRINT,TIMEPOINTS=T20,NSET=N5
U

*NODE FILE,TIMEPOINTS=T20,OUTPUT=2D
U,S

*EL FILE,TIMEPOINTS=T20,SECTION FORCES
S

*ENDSTEP

*STEP,PERTURBATION

**STATIC

*BUCKLE
1,0.01,50

*ENDSTEP