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NASTRAN: sol 106. FPU reset error

NASTRAN: sol 106. FPU reset error

NASTRAN: sol 106. FPU reset error

(OP)
Hello!
I have the wing copmosite panel that consists of honeycomb panel itself (modeled by mean of laminate elements) and brackets (that is modeled by mean of plate elements). Brackets and panel connected via cweld elements. Load is pressure on panel. Constraints are on brackets.
Static analysis is ok. But when I run nonlinear static analysis (106) I receive UWM 4896:

 *** USER WARNING MESSAGE 4698 (DCMPD)
     STATISTICS FOR DECOMPOSITION OF MATRIX KLLRH   .
     THE FOLLOWING DEGREES OF FREEDOM HAVE FACTOR DIAGONAL RATIOS GREATER THAN
      1.00000E+08 OR HAVE NEGATIVE TERMS ON THE FACTOR DIAGONAL.
     USER INFORMATION:
     THIS MESSAGE MAY BE IGNORED IF NO GRID POINT IDS OR
...........................
     User's Guide.
1    P=-2460 FI=0                                                             APRIL  20, 2008  NX NASTRAN  1/29/07   PAGE     9
                                                                                                                             GRID POINT ID       DEGREE OF FREEDOM   MATRIX/FACTOR DIAGONAL RATIO        MATRIX DIAGONAL                                
                                                                                                                                    
            4421                    T3                  -4.96299E+02                   3.34151E+04
            4439                    T3                  -1.16222E+02                   2.36758E+04
            4448                    T1                  -3.96610E+01                   6.78013E+03
            4461                    T3                  -2.29087E+03                   5.31481E+03
            4483                    T3                  -2.07175E+01                   5.21180E+03
            4596                    R3                  -3.46916E+01                   6.69773E+03
            4700                    T3                  -6.99364E+02                   6.76800E+03
            4703                    T3                  -3.41159E+03                   6.79904E+03
            5050                    R1                  -1.48623E+01                   6.31438E+03
 ^^^ USER INFORMATION MESSAGE 9004 (NLSTATIC)    
 ^^^ FOR THIS ITERATION, THE DIFFERENTIAL STIFFNESS WILL BE  IGNORED TO AVOID DECOMPOSITION OF A NON-POSITIVE                      
     DEFINITE STIFFNESS MATRIX.

Then solution reaches load step 1.0 and when output listing begins such messages occurs:

 MAIN: The FPU has been reset after floating point exception.
 MAIN: For reference, A(MAINAL)   =   4012B0, A(/SYSTEM/) =  1C930C0           
 MAIN:                A(/XNSTRN/) =  39E0020                                   
 MAIN: "Floating point overflow" (C0000091) exception encountered.
 MAIN: Exception occurred at address 017838C8.
 MAIN: Context Flags 0001003F
 MAIN: EAX 00000001  EBX 0012F380  ECX 000000C1  EDX 00000000  ESI 00000001  EDI  00000004
 MAIN: EBP 00000000  ESP 0012F340  EIP 017838CF  EFLAGS 00010202

I've tried to do eigenvalue analysis - it's ok. The model is constrained properly. Also I checked mesh quality - it's ok.
But most strange thing is when I deleted a part of one bracket solution ended correctly. And when I meshed that part again this error occured. But definitely, the point is not in this part, because mesh is good.
And even when I constrained all separate parts of my model this error occurs again!
Also I tried to replace cweld elements with RBE2 - no effect.

Is there any ideas about this?

Thanks in advance
 

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