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No Linear Buckling results in SOL105

Hi Folks,

 

I met some problem. I run the solution SOL105 to check the Eigenmodes of the structure, but no results for Buckling Methode are present. I recieved only the results for Linear Statuc analysis.

It is strange because I can see the Eigenvalues Extraction tab in Solution Monitor.

What could happen ?

 

I used default parameters for the analysis and never met such problem before.

What statement in output files (ex. in *.f06 file) can indicate that something is wrong with SOL 105 solution ?


It's quite simple model that's why I am confused ....

What happened ?

4 REPLIES

Re: No Linear Buckling results in SOL105

Dear Tomek,

Well, first you have a little error when you mix "nonlinear buckling" with "SOL105": with NX NASTRAN the NonLinear basic module is SOL106, but "Linear" Buckling Analysis is SOL105, based in the Euler buckling.

 

The workflow for Linear Buckling (SOL105) is quite simply, surely you have forgot to drag &drop the loading under the "Buckling Load - Subcase", revise your model, or better post here all your files (*.prt, *.fem, *.sim) and we will take a look to it, OK?.

 

 

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/

Re: No Linear Buckling results in SOL105

[ Edited ]

Hi Blas !

 

Good to see that you are here, you have always good solutions Smiley Happy

From the begining, I try to perform Linear Buckling only (didn't mention SOL 106 anywhere before?).

 

When going into the subject. I can not give you the files, because of the company rules, but see below:

- number of desired eigenmodes is set to 10 and no limitations for lower and upper limit are defined

- loads and constraints are given as presented

 

 

the fatal messages i get in *.f06 when eigenvalues are beeing extracted (based on the Job Monitor) are:

 


NASTRAN Msg: *** SYSTEM FATAL MESSAGE 7340 (LNNHERR) PROCESS ERROR REPORTED BY SUBROUTINE LNNP2CD (IER= -725) NASTRAN Msg: *** SYSTEM FATAL MESSAGE 7340 (LNNHERR) WARNING REPORTED BY SUBROUTINE LNNDRVD (IER= 725) NASTRAN Msg: *** SYSTEM FATAL MESSAGE 3003 (READ) ATTEMPT TO READ PAST THE END OF A LOGICAL RECORD IN DATA BLOCK SCRATCH (FILE 315) IN SUBROUTINE REIGL3 NASTRAN Msg: *** SYSTEM FATAL MESSAGE 3003 (READ) ATTEMPT TO READ PAST THE END OF A LOGICAL RECORD IN DATA BLOCK SCRATCH (FILE 315) IN SUBROUTINE REIGL3 NASTRAN Msg: 0FATAL ERROR See NASTRAN F06 file for more details. Total messages: 0 WARNINGS and 5 FATALS

 

When I change the Lanczos data to "NONE" ( so default values shall be taken) i get errors as follows:

NASTRAN Msg:  *** USER WARNING MESSAGE 4506 (GPFDEV)
                  TOTAL STRAIN ENERGY IS ZERO. THE PERCENT OF TOTAL STRAIN ENERGY IS ALSO 
SET TO ZERO.
NASTRAN Msg:  *** SYSTEM FATAL MESSAGE 3001 (CASE)
                  THE INPUT DATA BLOCK NAMED CASERS   AT POSITION      1 DOES NOT EXIST.
NASTRAN Msg:  *** SYSTEM FATAL MESSAGE 3001 (CASE)
                  THE INPUT DATA BLOCK NAMED CASERS   AT POSITION      1 DOES NOT EXIST.
NASTRAN Msg: 0FATAL ERROR
             See NASTRAN F06 file for more details.


Total messages: 1 WARNING and 3 FATALS

results for "NONE" Lanczos data:

 

 

what to do with this ?

Re: No Linear Buckling results in SOL105

I think that I found a solution for that problem.

 

I do not know why, but this problem occured when I used QUAD8 elements. When changed them to QUAD4 the problem disappeared.


Is there any limitation for using such elements (QUAD8) for linear buckling ?

Re: No Linear Buckling results in SOL105

Dear Tomek,

You will need to play with the MAXRATIO value in the NASTRAN BULK DATA, check the F06 file and see the error and use a value a little bigger and you are done, OK?.

Best regards,

Blas.

Blas Molero Hidalgo, Ingeniero Industrial, Director
IBERISA • 48004 BILBAO (SPAIN)
WEB: http://www.iberisa.com
Blog Femap-NX Nastran: http://iberisa.wordpress.com/