nvh category nvh characteristicfrequency (hz) steady state frequency response ride< 5 shake5 - 40...
TRANSCRIPT
![Page 1: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/1.jpg)
NVH Category
NVH Characteristic Frequency (Hz)Steady State Frequency Response• Ride < 5• Shake 5 - 40• Boom 20 - 100• Moan 100 - 150• Structural Borne Noise 150 – 500• Air Borne Noise > 500
Transient Response• Harshness 20 - 100
![Page 2: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/2.jpg)
Single Degree of Freedom
Frequency (Hz)
Am
plit
ud
e (2
0% D
amp
ed)
Control byDynamicStiffness
Control byMass
Control byDamping
Isolation Region
2fn * fn
![Page 3: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/3.jpg)
Dynamic Stiffness
Dynamic Stiffness:
(K - m ω2) – j C ω
K* = ----------------------------------
(K - m ω2)2 + (C ω)2
Mass M
Damping CStiffness K
ω = 2* π*f
f is the frequency
![Page 4: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/4.jpg)
Pure Tone
• Sound at a single frequency
• Sound Pressure– Objective measurement
• dB– Logarithmic of sound pressure
• dBA– A-Weighted to adjust for ear sensitivity
![Page 5: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/5.jpg)
Human Sensitivity
• More constant across frequency range with velocity
• Hearing range 20 – 2000 Hz
• Depends on overall level
• Sound at one frequency may mask by other frequencies
• Depends on age, sex and other factors
![Page 6: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/6.jpg)
Tactile ResponseSubjective-Objective
Acceleratio
nA
cceleration
FrequencyFrequency
SR = 6SR = 6
SR = 5SR = 5
![Page 7: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/7.jpg)
Tactile ResponseSubjective-Objective (2)
Velo
cityV
elocity
FrequencyFrequency
SR = 6SR = 6
SR = 5SR = 5
![Page 8: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/8.jpg)
Sound Pressure Level and A Weighting
![Page 9: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/9.jpg)
NVH Classification
• Operating Condition– Idle, Low Speed, Cruising, POT, WOT
• Subjective Evaluation– Shake, Boom, Noise, Harshness
• Objective Measurement– Sound Pressure, Acceleration
• Frequency Range• Source
– Powertrain, Road, Exhaust
![Page 10: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/10.jpg)
NVH Subjective Rating
MostTargetsNo Sale
![Page 11: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/11.jpg)
NVH Objectives
• Assess vehicle responses relative to design targets:–Tactile responses
• Seat track• Steering column• Toe pan
–Acoustic responses• Driver’s ear• Front Passenger’s ear• Rear passenger’s ear
![Page 12: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/12.jpg)
Shake
• 5 – 40 Hz
• Idle Shake
• Isolated Road Shake
• Rough Road Shake
• Smooth Road Shake– Wheel/Tire Imbalance– Tire Force Variation
![Page 13: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/13.jpg)
Design For Shake
• Body vertical, lateral bending and torsion modes
• Front end bending and torsion modes• Front floor modes• Steering column modes• Seat modes• Avoid stickiness of the shock and CV
joints that causes high force input and resonance in smooth road shake
![Page 14: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/14.jpg)
Design For Shake (2)
• Mode separation and mode shape management of engine bounce, roll, pitch and yaw rigid body modes
![Page 15: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/15.jpg)
Boom
• 20 - 100 Hz
• Idle Boom
• Isolated Road Boom
• Rough Road Boom
![Page 16: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/16.jpg)
Body Design for Boom
• 1st and 2nd fore-aft acoustic modes• Body 1st and 2nd order vertical bending• Front floor vertical bending• Dash panel fore-aft bending• Quarter panel bending• Fuel tank bounce• Spare tire tub bounce• Decklid, liftgate or lower back panel pumping
![Page 17: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/17.jpg)
Structural Borne Noise
• 100 - 500 Hz
• Powertrain Noise
• Rough Road Noise
• Gear Whine
![Page 18: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/18.jpg)
Design For Noise
• Most of the vibration energy imparted to the vehicle is below 150 Hz.
• Below 150 Hz:– Body structure is important for controlling noise and
vibration – Lack of structure usually results in costly design and
tooling changes• Above 150 Hz:
– Can be resolved with relatively simple structure modifications, such as bead patterns, or damping treatments.
![Page 19: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/19.jpg)
Design For Noise (2)
• Powertrain Bending Isolation• Powertrain Bracket Isolation
![Page 20: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/20.jpg)
0 5 10 15 20 25 30 35 40 45 50
CHASSIS/POWERTRAIN MODES
Ride ModesPowertrain Modes
Suspension Hop and Tramp Modes
Suspension Longitudinal ModesExhaust Modes
0 5 10 15 20 25 30 35 40 45 50
BODY/ACOUSTIC MODES
Body First Bending (22Hz)
Body First Torsion (25Hz) Steering Column First Vertical Bending (29Hz)
0 5 10 15 20 25 30 35 40 45 50
EXCITATION SOURCES
Inherent Excitations (General Road Spectrum, Reciprocating Unbalance, Gas Torque, etc.)Process Variation Excitations (Engine, Driveline, Accessory, Wheel/Tire Unbalances)
First Order Wheel/Tire Unbalance (5-75MPH)V8 Idle (500-550RPM)
Hot Cold
Hz
Hz
Hz
First F/A Acoustic Modes (48Hz)
Modal Chart
![Page 21: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/21.jpg)
Body-in-White Targets
• Static Stiffness– Bending– Torsion
• Normal Modes– Vertical bending– Torsion– Lateral bending
![Page 22: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/22.jpg)
Trimmed Body Targets
• Normal Modes– Vertical bending– Torsion– Lateral bending– Front end bending– Front end torsion
![Page 23: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/23.jpg)
Instrument Panel/Column Targets
• Normal Modes– Vertical bending– Lateral bending
![Page 24: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/24.jpg)
Seat Targets
• Normal Modes– On Bedplate
• Fore aft• Lateral
– In Vehicle• Fore aft• Lateral
• Different row may have different target
![Page 25: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/25.jpg)
Idle Load
![Page 26: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/26.jpg)
recipreciprecip amF *
borecrankboregas APPF *)(
tan**)( hFFT recipgastotal
r
h
Pbore
Pcrank
mrecip
arecip
L
Idle Torque
![Page 27: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/27.jpg)
coscos rLh
2sin1cos LL
cossin1 2 rLh
2sin1cos
L
r sinsin
r
h
Pbore
Pcrank
mrecip
arecip
L
Piston Displacement
![Page 28: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/28.jpg)
dt
duvw
dt
dvuw
dt
dwuv
dt
duvwdt
dv
dt
du
dt
vuddt
dunu
dt
du
dt
d
dt
ddt
d
dt
d
nn
)(
sincos
cossin
1
r
h
Pbore
Pcrank
mrecip
recip
L
Trigonometric Derivatives
![Page 29: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/29.jpg)
222
222
2
sin
sincossin
sin
sincossin
)coscos(
rL
rr
rL
rr
dt
d
rLdt
d
dt
dhv
r
h
Pbore
Pcrank
mrecip
arecip
L
Piston Velocity
![Page 30: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/30.jpg)
23222
224
222
22
222
)sin(
sincos
sin
2coscos
)sin
sincos(sin)(
rL
r
rL
rr
rL
r
dt
dr
dt
dva
r
h
Pbore
Pcrank
mrecip
arecip
L
Piston Acceleration
![Page 31: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/31.jpg)
Smooth Road Shake
![Page 32: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/32.jpg)
Wheel/Tire Imbalance Definition
• Simulation– Shake caused by the unbalanced inertia forces from the
high speed rotation of the unbalanced wheel in vehicle cruising
• Load– 1.0 oz-inch (Sensitivity) unbalanced force at the spindles– Both vertical and fore-aft loads with vertical load trailing
fore-aft load by 90 degrees
• Applications– Front wheel in-phase, Front wheel out-of-phase, Rear
wheel in-phase and Rear wheel out-of-phase
![Page 33: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/33.jpg)
Wheel/Tire Imbalance Calculation
• F = mr2
– F is imbalance Force (N)– m is imbalance mass (Mg)– r is imbalance radius (mm) is rotation speed (rad/sec)
• F = 1.0 oz-in = 1.0 * 28.3 * 10-6 (Mg/oz) * 25.4 (mm/inch) * 4 * 2 * f2 = 0.0284 * f2 (N)– f is frequency (cycles/sec)
![Page 34: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/34.jpg)
Wheel/Tire ImbalanceSpeed Map
• The wheel/tire speed map (frequency v.s. vehicle speed) is dependent on the wheel/tire size, the wheel/tire stiffness and the payload
• V = 2 * π * Tire Effective Radius * Frequency• However, the Frequency/Vehicle Speed(MPH) is
typically around 0.2• Based on the above assumption, the frequency
range of interest from 25 MPH to 125 MPH is– 5 Hz to 25 Hz
![Page 35: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/35.jpg)
Tire Force Variation Definition
• Simulation– Shake caused by the variation of the radial stiffness of
the tires
• Load– 1.0 lbf (Sensitivity) variation force at the spindles
– Vertical load only
• Applications– Front wheel in-phase, Front wheel out-of-phase, Rear
wheel in-phase and Rear wheel out-of-phase
![Page 36: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/36.jpg)
Tire Force VariationSpeed Map
• The wheel/tire speed map (frequency v.s. vehicle speed) is dependent on the wheel/tire size, the wheel/tire stiffness and the payload
• V = 2 * π * Tire Effective Radius * Frequency• However, the Frequency/Vehicle Speed(MPH) is
typically around 0.2• Based on the above assumption, the frequency
ranges of interest from 25 MPH to 125 MPH are– First Order : 5 Hz to 25 Hz– Second Order : 10 Hz to 50 Hz
![Page 37: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/37.jpg)
Rough Road Noise
![Page 38: NVH Category NVH CharacteristicFrequency (Hz) Steady State Frequency Response Ride< 5 Shake5 - 40 Boom20 - 100 Moan100 - 150 Structural Borne Noise150](https://reader035.vdocument.in/reader035/viewer/2022062421/56649d0b5503460f949de712/html5/thumbnails/38.jpg)
Spatial PSD Road Profile
• Spatial Frequency ( Cycles / mm)– Wave number– 1 / wavelength
• PSD Amplitude (mm^2 / (cycles / mm))• Power Regression Analysis (Y = 1.7872 * X-0.6729)
Spacial PSD Road Profile
y = 1.7872x-0.6729
R2 = 0.6538
1
10
100
1000
0.0001 0.0010 0.0100 0.1000
Wave Number (cycles/mm)
PS
D (
mm
^2
/(c
yc
les
/mm
))