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difference on analysis occured in V14 and V8

difference on analysis occured in V14 and V8

difference on analysis occured in V14 and V8

(OP)
V14 vs. V8

1.)
I modeled a simple howe truss in SAP V.14 and compared it with SAP V.8.

i only have released the moments(M2&M3) for the diagonal and vertical members of the truss, having my top and bottom cord with no moment releases.

SAP v. 8 analysis results does not show any WARNINGS.
but SAP v.14 has warnings using the standard solver.

the warning in SAP v 14 goes something like this:

"
 B E G I N   A N A L Y S I S                                2010/08/18  18:25:13


 RUNNING ANALYSIS WITHIN THE GUI PROCESS
 USING THE STANDARD SOLVER (PROVIDES COMPLETE INSTABILITY INFORMATION)


 E L E M E N T   F O R M A T I O N                                      18:25:13



 L I N E A R   E Q U A T I O N   S O L U T I O N                        18:25:13

 FORMING STIFFNESS AT ZERO (UNSTRESSED) INITIAL CONDITIONS

 TOTAL NUMBER OF EQUILIBRIUM EQUATIONS     =          63
 APPROXIMATE "EFFECTIVE" BAND WIDTH        =          15

 NUMBER OF EQUATION STORAGE BLOCKS         =           1
 MAXIMUM BLOCK SIZE (8-BYTE TERMS)         =         862
 SIZE OF STIFFNESS FILE(S) (BYTES)         =       6.996 KB

 NUMBER OF EQUATIONS TO SOLVE              =          63

 * * * W A R N I N G * * *
 NUMERICAL PROBLEMS ENCOUNTERED DURING EQUATION ASSEMBLY:

  TYPE  LABEL DOF     X-COORD     Y-COORD     Z-COORD       PROBLEM       VALUE
 ----- ------- -- ----------- ----------- ----------- ------------- -----------
 Joint       7 RX   -2.666667     .000000     .000000 Diag = 0 -->     1.00E-10
 Joint       8 RX   -1.333333     .000000     .000000 Diag = 0 -->     1.00E-10
 Joint       6 RX     .000000     .000000     .000000 Diag = 0 -->     1.00E-10
 Joint       9 RX    1.333333     .000000     .000000 Diag = 0 -->     1.00E-10
 Joint      10 RX    2.666667     .000000     .000000 Diag = 0 -->     1.00E-10

 * * * W A R N I N G * * *
 NUMERICAL PROBLEMS ENCOUNTERED DURING EQUATION SOLUTION:

  TYPE  LABEL DOF     X-COORD     Y-COORD     Z-COORD       PROBLEM       VALUE
 ----- ------- -- ----------- ----------- ----------- ------------- -----------
 Joint      15 RZ   -2.666667     .000000    1.000000 Lost accuracy 15.5 digits
 Joint      16 RZ   -1.333333     .000000    2.000000 Lost accuracy 15.8 digits
 Joint      17 RZ    1.333333     .000000    2.000000 Lost accuracy 15.8 digits
 Joint      18 RZ    2.666667     .000000    1.000000 Lost accuracy 15.3 digits

 * * * W A R N I N G * * *
 EXCESSIVE LOSS OF ACCURACY WAS DETECTED DURING THE SOLUTION OF EQUATIONS
 NUMBER OF DIGITS LOST EXCEEDED 11.0


 * * * W A R N I N G * * *
 THE STRUCTURE IS UNSTABLE OR ILL-CONDITIONED !!
 CHECK THE STRUCTURE CAREFULLY FOR:
 - INADEQUATE SUPPORT CONDITIONS, OR
 - ONE OR MORE INTERNAL MECHANISMS, OR
 - ZERO OR NEGATIVE STIFFNESS PROPERTIES, OR
 - EXTREMELY LARGE STIFFNESS PROPERTIES, OR
 - BUCKLING DUE TO P-DELTA OR GEOMETRIC NONLINEARITY, OR
 - A FREQUENCY SHIFT (IF ANY) ONTO A NATURAL FREQUENCY


 NUMBER OF EIGENVALUES BELOW SHIFT         =           0


 L I N E A R   S T A T I C   C A S E S                                  18:25:13

 USING STIFFNESS AT ZERO (UNSTRESSED) INITIAL CONDITIONS

 TOTAL NUMBER OF CASES TO SOLVE            =           1
 NUMBER OF CASES TO SOLVE PER BLOCK        =           1

 LINEAR STATIC CASES TO BE SOLVED:

 CASE: DEAD


 A N A L Y S I S   C O M P L E T E                          2010/08/18  18:25:13"

Does how does this differ?is SAP v.14 CORRECT?
you can model it on your own.

2.)
and i have used also the multi-threaded solver and deleted the supports for this type of truss and runned the program for analysis. but SAP14 shows "NO" warnings. how does this happen?

please help.
thanks a lot in advance!!

cprr0107

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