Problem with creating beam model

[adrenalin123]

Hello everybody!

I am currently working on creating a beam model which consists of several beams connected by nodes. They are constrained by a single 6-DOF-zero-displacement in the first node. Everytime I create the beams in a line (that means they all have the same direction) everything works fine. As soon as I create them having angles between them, the analysis stops with the famous "excessive pivot ratios" mistake. I just don't know what might fix the problem. Could anybody please help me?

Here is the bdf with a test version of two beams:

$ NASTRAN input file created by the Patran 2010 (MD Enabled) input file
$ translator on February 07, 2011 at 13:52:45.
$ Direct Text Input for Nastran System Cell Section
$ Direct Text Input for File Management Section
$ Direct Text Input for Executive Control
$ Linear Static Analysis, Database
SOL 101
CEND
$ Direct Text Input for Global Case Control Data
TITLE = MD Nastran job created on 07-Feb-11 at 13:46:18
ECHO = NONE
SUBCASE 1
$ Subcase name : lc1
SUBTITLE=lc1
SPC = 2
LOAD = 2
DISPLACEMENT(SORT1,REAL)=ALL
SPCFORCES(SORT1,REAL)=ALL
STRESS(SORT1,REAL,VONMISES,BILIN)=ALL
BEGIN BULK
$ Direct Text Input for Bulk Data
PARAM POST -1
PARAM PRTMAXIM YES
$ Elements and Element Properties for region : beam1
PBARL 1 1 BAR
1. 1.
$ Pset: "beam1" will be imported as: "pbarl.1"
CBAR 1 1 1 2 0. 0. 1.
CBAR 2 1 2 3 0. 0. 1.
$ Referenced Material Records
$ Material Record : a
$ Description of Material : Date: 07-Feb-11 Time: 13:50:56
MAT1 1 1.+9
$ Nodes of the Entire Model
GRID 1 0. 0. 0.
GRID 2 1. 1. 0.
GRID 3 0. 1. 1.
$ Loads for Load Case : lc1
SPCADD 2 1
LOAD 2 1. 1. 1
$ Displacement Constraints of Load Set : dof1
SPC1 1 123456 1
$ Nodal Forces of Load Set : f1
FORCE 1 3 0 10. 0. 0. 1.
$ Referenced Coordinate Frames
ENDDATA 762d9011


Regards
Martin

 

[adrenalin123]

Hello again!

Problem is solved. Poisson ratio was missing. I didn't expect it to be necessary.

Thanks anyways!