SAR-LINE Method - A new method for Squeak & Rattle simulation and test developed at SAAB

Transcription

1 SAR-LINE Method - A new method for Squeak & Rattle simulation and test developed at SAAB Saab Automobile AB 5 th European HyperWorks Technology Conference Bonn, Germany 2011 November 8 th 9 th Page 1

2 Squeak & Rattle (SAR) causes Material pairs Manufacturing Assembling Surface finishing Relative displacement Temperature Tolerances Humidity Road load Page 2

3 Instrument panel (IP) assembly SAAB 9-5 Page 3

4 IP assembly on quiet shaker F(t) Deformation scale factor 50! Page 4

5 Parameters Load Rel disp in local Coordinate System (CS) Global stiffness Local stiffness Clips/snaps stiffness Contact / gap Load Relative displacement SAR-LINE SAR evaluation Page 5

6 Global stiffness Modal correlation Test - FEM MAC Foil (shell) - Only the lowest modes are represented Foam (solid) - Improved material data for plastic and foam/foil (Young s modulus) Page 6

7 Modal correlation Laser Scanning Vibrometer Page 7

8 Local stiffness MAC value Simulation with shell elements: - thickness: t - mass: m - Young s modulus: E ω ~ k(e,t)/m Mode # Simulation [Hz] 2130 MPa Simulation [Hz] 2600 MPa Test [Hz] MAC value [ - ] Test Page 8

9 [m/s 2 ] [mm] S&R Cockpit test on quiet shaker Global stiffness Local stiffness Clips/snaps stiffness Contact / gap Load Load Relative displacement Part I Rattle Q w v Squeak u Z Y X GAP P Part II T [s] Samplings frequency SF T [s] Page 9

10 Contact / gap SAR-LINE method Master surface x rattle z squeak 1001 Local CS: - aligned to master surface - assigned as analysis CS to node # 1001 and 2001 RBE3 3D line (SAR line path) RBE Slave surface TCL script in HyperMesh SAR line numbering convention: SAR line # 1065: 1001 / 2001 to 1065 / 2065 SAR line # 3099: 3001 / 4001 to 3099 / Page 10

11 Contact / gap SAR line RBE3 Local CS RBE3 SAR lines Page 11

12 Input signal PSD load definition for quiet shaker table Time signal Time signal length? Page 12

13 Time length of input signal vs relative displacement Page 13

14 Post processing relative displacement using HyperGraph Rel disp in node Gap closing Max value 0.45 mm - Gap opening T = 3 s Ranking the peak amplitudes Mean value 0.19 mm 20 % Mean value of 20 % of highest peak amplitudes Page 14

15 [m/s 2 ] [mm] Analysis process FFT - Frequency response - ifft delta f = f(sf, T, 2 n ) TLOAD (random signal) in time domain Load RADIOSS Modal transient analysis TSTEP = 1/SF Displacement in local CS (LCS) in time domain on SAR line Displacement in LCS T [s] Samplings frequency SF T [s] Page 15

16 SAR-LINE evaluation process Input Node pairs on SAR lines: *.dat file GRID node # Results on SAR line *.pch X Y Z *.mat Disp T1/T2/T3 in LCS Time = time length of input signal Purpose Global Line Point Output Relative displacement (max or % value of highest peak amplitude) Comparing design variants : material, mounting points Correlation to rattle and squeak occurance 3D contour plot of all SAR lines showing the magnitude of rel disp Ranking all SAR lines (Histogram) Relative displacement along the SAR line (in LCS) User option: Magnitude, Squeak, Rattle Relative displacement at each node pair in time domain Ranked amplitudes Page 16

17 Global level - Contour plot Page 17

18 Global level - Ranking SAR Line ranking - Magnitude - Mean over 30% highest values (HV) mm Line Page 18

19 Line level z Local CS in each SAR line point y Node 7001 Node 7027 Node 7001 Node 7027 Page 19

20 Point level Node 7015 and 8015 z y Mean value over 30 % HV Page 20

21 Ranking comparison of design variants Variant 1 Remove mounting point Variant 2 Change material from PP-LGF30 to ABS PC Page 21

22 Line - comparison of design variants Variant 1 Remove mounting point Node 3035 Node 3001 Variant 2 Change material from PP-LGF30 to ABS PC Node 3001 Node 3035 Page 22

23 Gap line vs contact line Contact line Gap line Rattle correlation Peak amplitude > Gap size Squeak correlation Peak to peak amplitude > 1/Impulse rate Peak to peak amplitude Gap size Rel disp in contact plane Page 23

24 Rattle correlation Rel disp in node gap = mean crit Ranked peak amplitudes when rattle sound starts? % Rattle occurs when gap = mean crit value of? % hightest peak amplitudes TEST SIMULATION Displacement measured with 3D Laser Vibrometer Displacement simulated with modal transient solver F (t) F (t) Page 24

25 Rattle correlation Page 25

26 Rattle correlation Page 26

27 s sut at sr ot o m ] [N ecr of t eser ] g[ n iot ar le ecca Squeak correlation date time :19:02 stick-slip test stand parameters normal force temperature humidity rel. velocity 50,3 25,09 54,06 5,8 N C % rel. F. mm/s Relative velocity stick-slip risk RPZ grade groan rate grade acceleration grade impulse rate 10,33 27,00 5,72 max. accel. groan rate impulse rate testing duration impulses 22,1 0,10 1,4 26,1 212 g khz 1/mm s Impulse rate dyn. frict. force dyn. COF 8,3 0,17 N stat. frict. force stat. COF 13,4 0,27 N version 2.00 Page 27

28 Squeak correlation in contact plane Relative displacement (in contact plane) 1/Impulse rate < peak to peak amplitude Peak to peak amplitude 0.44 mm Relative velocity Relative velocity max relative velocity Max value 22 mm/s Page 28

29 SAR-LINE applications interior / exterior Page 29

30 SAR-LINE applications interior / exterior Volvo 3P By courtesy of Volvo 3P Page 30

31 Interior design process Start of production Virtual engineering Validation Modal analysis Pulse analysis (Global CS) SAR-LINE analysis Root cause analysis / test support Page 31

32 Tack så mycket! Page 32