Hello!,
The QUAD mesh of the sphere is a litle disaster, you are violating the minimum quality checks imposed by nastran:
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* * N X N a s t r a n * *
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* * VERSION - 8.1 * *
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* * OCT 6, 2011 * *
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* *Intel64 Family 6 Model 23 Steppi * *
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* *Intel(R) Core(TM)2 Quad CPU Q955 * *
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* * Windows Vista Service Pack 2 * *
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* * Compiled for X86-64 * *
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Welcome to NX Nastran
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M O D E L S U M M A R Y
NUMBER OF GRID POINTS = 298
NUMBER OF CBAR ELEMENTS = 120
NUMBER OF CQUAD4 ELEMENTS = 208
*** USER INFORMATION MESSAGE 7555 (GMTSTD)
FINITE ELEMENT GEOMETRY CHECK RESULTS EXCEED TOLERANCE LEVELS FOR THE FOLLOWING ELEMENTS.
USER ACTION: USE THE GEOMCHECK (EXECUTIVE CONTROL STATEMENT) KEYWORD=VALUE TO CHANGE TOLERANCE VALUES IF DESIRED.
User information:
Element Geometry test tolerance levels and message limits can be changed by the GEOMCHECK Executive Control statement.
The following keywords are available:
Q4_SKEW - to modify the CQUAD4/CQUADR skew angle test tolerance.
Q4_TAPER - to modify the CQUAD4/CQUADR taper ratio test tolerance.
Q4_WARP - to modify the CQUAD4/CQUADR warping coefficient test tolerance.
Q4_IAMAX - to modify the CQUAD4/CQUADR maximum interior angle test tolerance.
Q4_IAMIN - to modify the CQUAD4/CQUADR minimum interior angle test tolerance.
T3_SKEW - to modify the CTRIA3/CTRIAR skew angle test tolerance.
T3_IAMAX - to modify the CTRIA3/CTRIAR maximum interior angle test tolerance.
TET_AR - to modify the CTETRA aspect ratio test tolerance.
TET_EPLR - to modify the CTETRA edge node point length ratio test tolerance.
TET_DETJ - to modify the CTETRA determinant of the Jacobian matrix test tolerance.
TET_DETG - to modify the CTETRA determinant of the vertex points Jacobian matrix test tolerance.
HEX_AR - to modify the CHEXA aspect ratio test tolerance.
HEX_EPLR - to modify the CHEXA edge node point length ratio test tolerance.
HEX_DETJ - to modify the CHEXA determinant of the Jacobian matrix test tolerance.
HEX_WARP - to modify the CHEXA face warping coefficient test tolerance.
BEAM_OFF - to modify the CBEAM offset length ratio test tolerance.
BAR_OFF - to modify the CBAR offset length ratio test tolerance.
MSGLIMIT - to limit the number of messages that are generated.
MSGTYPE - to modify the severity level of the test.
A MAXIMUM OF 100 SKEW ANGLE (SA) TOLERANCE LIMIT VIOLATIONS WILL BE IDENTIFIED AND INDICATED BY xxxx.
A MAXIMUM OF 100 MIN INT. ANGLE (IA) TOLERANCE LIMIT VIOLATIONS WILL BE IDENTIFIED AND INDICATED BY xxxx.
A MAXIMUM OF 100 MAX INT. ANGLE (IA) TOLERANCE LIMIT VIOLATIONS WILL BE IDENTIFIED AND INDICATED BY xxxx.
A MAXIMUM OF 100 WARPING FACTOR (WF) TOLERANCE LIMIT VIOLATIONS WILL BE IDENTIFIED AND INDICATED BY xxxx.
A MAXIMUM OF 100 TAPER RATIO (TR) TOLERANCE LIMIT VIOLATIONS WILL BE IDENTIFIED AND INDICATED BY xxxx.
TOLERANCE LIMITS ARE: SA = 30.00, IA(MIN) = 30.00, IA(MAX) = 150.00, WF = 0.05, TR = 0.50 (xxxx = LIMIT VIOLATED)
ELEMENT TYPE ID SKEW ANGLE MIN INT. ANGLE MAX INT. ANGLE WARPING FACTOR TAPER RATIO
QUAD4 103 63.51 44.11 118.38 0.01 0.51 xxxx
QUAD4 125 64.01 44.71 105.56 0.01 0.52 xxxx
QUAD4 173 63.41 44.12 120.10 0.01 0.51 xxxx
E L E M E N T G E O M E T R Y T E S T R E S U L T S S U M M A R Y
TOTAL NUMBER OF TIMES TOLERANCES WERE EXCEEDED
ASPECT/ MINIMUM MAXIMUM SURFACE/FACE EDGE POINT JACOBIAN
ELEMENT TYPE SKEW ANGLE TAPER RATIO INTER. ANGLE INTER. ANGLE WARP FACTOR OFFSET RATIO LENGTH RATIO DETERMINANT
BAR N/A N/A N/A N/A N/A 0 N/A N/A
QUAD4 0 3 0 0 0 N/A N/A N/A
N/A IN THE ABOVE TABLE INDICATES TESTS THAT ARE NOT APPLICABLE TO THE ELEMENT TYPE AND WERE NOT PERFORMED.
FOR ALL ELEMENTS WHERE GEOMETRY TEST RESULTS HAVE EXCEEDED TOLERANCES,
QUAD4 ELEMENT ID 125 PRODUCED LARGEST TAPER RATIO OF 0.52 (TOLERANCE = 0.50).
Best regards,
Blas.
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Blas Molero Hidalgo
Ingeniero Industrial
Director
IBERISA
48011 BILBAO (SPAIN)
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