WS12 -1 NAS105, Workshop 12, May 2005 WORKSHOP 12 NORMAL MODES OF BODY IN WHITE

WS12 -2 NAS105, Workshop 12, May 2005

WS12 -3 NAS105, Workshop 12, May 2005 Tasks n Compute the first 20 modes of the body in white. n Check the modes. n Determine the number of modes below 400Hz. n Is the mesh fine enough for a frequency of 400Hz?

WS12 -4 NAS105, Workshop 12, May 2005 Problem Files n Required Files: car_bw.dat : Model of the Body in White n Solution Files: ws12s.bdf : Proposed Solution

WS12 -5 NAS105, Workshop 12, May 2005 Model Units: N, mm, s

WS12 -6 NAS105, Workshop 12, May 2005 Input Deck $ Body in White: Normal Modes $ $ Executive Control Statements $ SOL 103 DIAG 8 CEND $ $ Case Control Commands $ TITLE = Body in White: Normal Modes ECHO = SORT(EXCEPT, CQUAD4, CTRIA3, CBEAM, PSHELL, PBEAM, GRID) $ DISP(PLOT) = ALL $ SUBCASE 1 LABEL = First 20 Modes METHOD = 10 ESE(PLOT) = ALL EKE(PLOT) = ALL $ $ Body in White: Normal Modes $ $ Executive Control Statements $ SOL 103 DIAG 8 CEND $ $ Case Control Commands $ TITLE = Body in White: Normal Modes ECHO = SORT(EXCEPT, CQUAD4, CTRIA3, CBEAM, PSHELL, PBEAM, GRID) $ DISP(PLOT) = ALL $ SUBCASE 1 LABEL = First 20 Modes METHOD = 10 ESE(PLOT) = ALL EKE(PLOT) = ALL $

WS12 -7 NAS105, Workshop 12, May 2005 Input Deck (ctd.) SUBCASE 2 LABEL = First 5 Modes above 400Hz METHOD = 20 $ BEGIN BULK $ $ Bulk Data Deck $ PARAM, POST, 0 $ Results to.xdb $ $ Activate Grid Point Weight Generator $ PARAM, GRDPNT, 0 $ $ Output all Strain Energies $ PARAM, TINY, 0. $ SUBCASE 2 LABEL = First 5 Modes above 400Hz METHOD = 20 $ BEGIN BULK $ $ Bulk Data Deck $ PARAM, POST, 0 $ Results to.xdb $ $ Activate Grid Point Weight Generator $ PARAM, GRDPNT, 0 $ $ Output all Strain Energies $ PARAM, TINY, 0. $

WS12 -8 NAS105, Workshop 12, May 2005 Input Deck (ctd.) $ $ Request 20 lowest normal modes $ EIGRL, 10,,, 20 $ $ Request 5 lowest modes above 400Hz $ EIGRL, 20, 400.,, 5 $ $ Model $ INCLUDE 'car_bw.dat' $ ENDDATA $ $ Request 20 lowest normal modes $ EIGRL, 10,,, 20 $ $ Request 5 lowest modes above 400Hz $ EIGRL, 20, 400.,, 5 $ $ Model $ INCLUDE 'car_bw.dat' $ ENDDATA

WS12 -9 NAS105, Workshop 12, May 2005 Results: Resonance Frequencies 0 E I G E N V A L U E A N A L Y S I S S U M M A R Y (READ MODULE) BLOCK SIZE USED NUMBER OF DECOMPOSITIONS NUMBER OF ROOTS FOUND NUMBER OF SOLVES REQUIRED R E A L E I G E N V A L U E S MODE EXTRACTION EIGENVALUE RADIANS CYCLES GENERALIZED GENERALIZED NO. ORDER MASS STIFFNESS E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E+05 1 BODY IN WHITE: NORMAL MODES 0 E I G E N V A L U E A N A L Y S I S S U M M A R Y (READ MODULE) BLOCK SIZE USED NUMBER OF DECOMPOSITIONS NUMBER OF ROOTS FOUND NUMBER OF SOLVES REQUIRED R E A L E I G E N V A L U E S MODE EXTRACTION EIGENVALUE RADIANS CYCLES GENERALIZED GENERALIZED NO. ORDER MASS STIFFNESS E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E E+05 1 BODY IN WHITE: NORMAL MODES

WS NAS105, Workshop 12, May 2005 Results: Torsion

WS NAS105, Workshop 12, May 2005 Results: Vertical Bending

WS NAS105, Workshop 12, May 2005 Results: Horizontal Bending

WS NAS105, Workshop 12, May 2005 Results: Number of Modes below 400 Hz *** SYSTEM INFORMATION MESSAGE 6916 (DFMSYN) DECOMP ORDERING METHOD CHOSEN: BEND, ORDERING METHOD USED: BEND *** USER INFORMATION MESSAGE 5010 (LNCILD) STURM SEQUENCE DATA FOR EIGENVALUE EXTRACTION. TRIAL EIGENVALUE = D+06, CYCLES = D+02 NUMBER OF EIGENVALUES BELOW THIS VALUE = 1410 *** USER INFORMATION MESSAGE 5010 (LNCILD) STURM SEQUENCE DATA FOR EIGENVALUE EXTRACTION. TRIAL EIGENVALUE = D+06, CYCLES = D+02 NUMBER OF EIGENVALUES BELOW THIS VALUE = 1415 TABLE OF SHIFTS: (LNNRIGL) SHIFT # SHIFT VALUE FREQUENCY, CYCLES # EIGENVALUES BELOW # NEW EIGENVALUES FOUND E E E E BODY IN WHITE: NORMAL MODES *** SYSTEM INFORMATION MESSAGE 6916 (DFMSYN) DECOMP ORDERING METHOD CHOSEN: BEND, ORDERING METHOD USED: BEND *** USER INFORMATION MESSAGE 5010 (LNCILD) STURM SEQUENCE DATA FOR EIGENVALUE EXTRACTION. TRIAL EIGENVALUE = D+06, CYCLES = D+02 NUMBER OF EIGENVALUES BELOW THIS VALUE = 1410 *** USER INFORMATION MESSAGE 5010 (LNCILD) STURM SEQUENCE DATA FOR EIGENVALUE EXTRACTION. TRIAL EIGENVALUE = D+06, CYCLES = D+02 NUMBER OF EIGENVALUES BELOW THIS VALUE = 1415 TABLE OF SHIFTS: (LNNRIGL) SHIFT # SHIFT VALUE FREQUENCY, CYCLES # EIGENVALUES BELOW # NEW EIGENVALUES FOUND E E E E BODY IN WHITE: NORMAL MODES

WS NAS105, Workshop 12, May 2005 Results: Detail of High-Frequency Mode

WS NAS105, Workshop 12, May 2005 Additional Tasks n Rerun the analysis with QUAD4 and TRIA3 converted to QUADR and TRIAR respectively. n Comparison of Results: ModeFrequency QUAD4/TRIA3 Frequency QUADR/TRIAR Torsion33.5Hz34.2Hz Vertical Bending35.8Hz36.5Hz Horizontal Bending41.8Hz42.8Hz

WS NAS105, Workshop 12, May 2005