reading

Cover
Preface
1 Introduction
1. 1.1 Automotive Body Structure and Noise and Vibration Problems
2. 1.2 Transfer of Structural‐Borne Noise and Airborne Noise to Interior
3. 1.3 Key Techniques for Body Noise and Vibration Control
4. 1.4 Noise and Vibration Control During Vehicle Development
5. 1.5 Structure of This Book
2 Vibration Control of Overall Body Structure
1. 2.1 Introduction
2. 2.2 Overall Body Stiffness
3. 2.3 Control of Overall Body Stiffness
4. 2.4 Identification of Overall Body Modes
5. 2.5 Control of Overall Body Modes
6. Bibliography
3 Noise and Vibration Control for Local Body Structures
1. 3.1 Noise and Vibration Problems Caused by Vehicle Local Structures
2. 3.2 Body Plate Vibration and Sound Radiation
3. 3.3 Body Acoustic Cavity Mode
4. 3.4 Panel Contribution Analysis
5. 3.5 Damping Control for Structural Vibration and Sound Radiation
6. 3.6 Stiffness Control for Body Panel Vibration and Sound Radiation
7. 3.7 Mass Control for Body Panel Vibration and Sound Radiation
8. 3.8 Damper Control for Body Vibration and Sound Radiation
9. 3.9 Noise and Vibration for Body Accessory Components
10. Bibliography
4 Sound Package
1. 4.1 Introduction
2. 4.2 Body Sealing
3. 4.3 Sound Absorptive Materials
4. 4.4 Sound Insulation Materials and Structures
5. 4.5 Application of Sound Package
6. 4.6 Statistical Energy Analysis and Its Application
7. Bibliography
5 Vehicle Body Sensitivity Analysis and Control
1. 5.1 Introduction
2. 5.2 Source–Transfer Path–Response Model for Vehicle Body
3. 5.3 Characteristics and Analysis of Noise and Vibration Sources
4. 5.4 Dynamic Stiffness and Input Point Inertance
5. 5.5 Vibration−Vibration Sensitivity and Sound−Vibration Sensitivity
6. 5.6 Sound−Sound Sensitivity and Control
7. Bibliography
6 Wind Noise
1. 6.1 Introduction
2. 6.2 Mechanism of Wind Noise
3. 6.3 Control Strategy for Wind Noise
4. 6.4 Body Overall Styling and Wind Noise Control
5. 6.5 Body Local Design and Wind Noise Control
6. 6.6 Dynamic Sealing and Control
7. 6.7 Measurement and Evaluation of Wind Noise
8. 6.8 Analysis of Wind Noise
9. Bibliography
7 Door Closing Sound Quality
1. 7.1 Vehicle Sound Quality
2. 7.2 Evaluation Indexes of Sound Quality
3. 7.3 Evaluation Indexes of Automotive Sound Quality
4. 7.4 Evaluation of Door Closing Sound Quality
5. 7.5 Structure and Noise Source of Door Closing System
6. 7.7 Design Procedure and Example Analysis for Door Closing Sound Quality
7. 7.8 Sound Quality for Other Body Components
8. Bibliography
8 Squeak and Rattle Control in Vehicle Body
1. 8.1 Introduction
2. 8.2 Mechanism and Influence Factors of Squeak
3. 8.3 Mechanism and Influence Factors of Rattle
4. 8.4 CAE Analysis of Squeak and Rattle
5. 8.5 Subjective Evaluation and Testing of Squeak and Rattle
6. 8.6 Control of Body Squeak and Rattle
7. Bibliography
9 Targets for Body Noise and Vibration
1. 9.1 Target System for Vehicle Noise and Vibration
2. 9.2 NVH Targets for Vehicle‐Level Body
3. 9.3 NVH Targets for Trimmed Body
4. 9.4 NVH Targets for Body‐in‐White
5. 9.5 NVH Targets for Body Components
6. 9.6 Execution and Realization of Body Targets
7. Bibliography
Index
End User License Agreement

List of Tables

Chapter 02
1. Table 2.1 Modal frequencies for a vehicle’s body, steering wheel system, engine idling speed, and fan speed, and the corresponding excitation frequencies.
2. Table 2.2 Body modal table: overall body modes and local modes.
3. Table 2.3 Relationship between speed and frequency.
4. Table 2.4 Ratios between rotary machines’ speeds and engine speed, and their corresponding engine orders.
5. Table 2.5 Partial body modes.
Chapter 03
1. Table 3.1 Body panels and corresponding mode description.
2. Table 3.2 Body acoustic cavity modes and description.
3. Table 3.3 Body accessories and modes.
4. Table 3.4 Secondary‐beam structures and modes.
5. Table 3.5 Geometrical dimensions and physical parameters of a rectangular plate.
6. Table 3.6 Frequencies for the first 10 modes of a rectangular plate calculated by analytical formula and by the FE method.
7. Table 3.7 Comparison between structure mode and acoustic cavity mode.
8. Table 3.8 Modal frequencies of cavity modes with and without seats.
9. Table 3.9 Frequency range of body cavity modes for most passenger cars.
10. Table 3.10 Comparison of first three modal frequencies calculated by real cavity FE model, rectangular FE model, and simple calculation formula.
11. Table 3.11 Modal frequencies (Hz) for a flat plate and stiffened plates.
Chapter 04
1. Table 4.1 Overall body leakage and leakage area of each leaking portion.
Chapter 05
1. Table 5.1 Relationship among engine speed, order, and frequency of first four orders for a four‐cylinder engine.
2. Table 5.2 Excitation frequencies of first and second orders of tire’s dynamic imbalance at different vehicle speeds.
3. Table 5.3 Gear ratio of rotary machines to engine crankshaft for an engine.
Chapter 06
1. Table 6.1 Subjective scoring of wind noise.
Chapter 07
1. Table 7.1 Bark critical band.
2. Table 7.2 Relationship between loudness and sound pressure level.
3. Table 7.3 Ten‐point subjective evaluation system.
Chapter 08
1. Table 8.1 S&R severity coefficient (V).
2. Table 8.2 Weighting coefficient for different roads (R_i).

List of Illustrations

Chapter 01
1. Figure 1.1 Structure of a united body.
2. Figure 1.2 Structure of a trimmed body.
3. Figure 1.3 Classification of body structure.
4. Figure 1.4 Body frame structure.
5. Figure 1.5 Fender.
6. Figure 1.6 A door panel. (a) Outside. (b) Internal side.
7. Figure 1.7 A floor.
8. Figure 1.8 A roof.
9. Figure 1.9 A dash inner insulator.
10. Figure 1.10 Damping material on floor.
11. Figure 1.11 A sandwiched dash panel system.
12. Figure 1.12 Foaming material inside a frame cavity.
13. Figure 1.13 Source–transfer path–receiver model.
14. Figure 1.14 Transfer process of drumming to occupants: airborne noise.
15. Figure 1.15 Transfer process of airborne noise to occupants’ ears.
16. Figure 1.16 Transmission of structural‐borne sound in rails.
17. Figure 1.17 Sources and body transfer paths of airborne noise and structural‐borne noise.
18. Figure 1.18 Structural wave pattern of a vibrated panel: first mode.
19. Figure 1.19 Flat plate and bead plate.
20. Figure 1.20 Comparison of magnitude of sound radiation of an undamped panel and a damped panel.
21. Figure 1.21 First acoustic cavity mode of a vehicle body.
22. Figure 1.22 Engine mounting brackets. (a) A bracket. (b) A bracket connected with an engine mounting.
23. Figure 1.23 Diagram of a steering system.
24. Figure 1.24 Noise reduction (NR) increases with frequency increase.
25. Figure 1.25 Noise reduction (NR) comparison of an ideal body without holes and a body with holes.
26. Figure 1.26 Apertures/holes on a dash panel.
27. Figure 1.27 Reflection and absorption of a sound wave.
28. Figure 1.28 Sound absorption coefficients versus frequency for the three types of sound absorptive materials.
29. Figure 1.29 Reflection, absorption, and transmission of a sound wave.
30. Figure 1.30 Relationship between a system and input and output.
31. Figure 1.31 Transfer processes of sound–vibration sensitivity and vibration–vibration sensitivity.
32. Figure 1.32 Transfer process of acoustic sensitivity.
33. Figure 1.33 Sound–vibration sensitivity curves.
34. Figure 1.34 A color map of sound–vibration sensitivity.
35. Figure 1.35 Airflow vortex layer and stable layer.
36. Figure 1.36 Underbody belly pan cover.
37. Figure 1.37 Source–transfer path–receiver model used in wind noise analysis.
38. Figure 1.38 Curve and spectrum of a door closing sound. (a) Time‐domain curve. (b) Time‐frequency color spectrum.
39. Figure 1.39 (a) Squeak. (b) Rattle.
40. Figure 1.40 A vehicle modal frequency table.
Chapter 02
1. Figure 2.1 Relationship between interior noise and body stiffness.
2. Figure 2.2 Relationship between subjective rating and body stiffness.
3. Figure 2.3 (a) A segment of a beam; (b) cross‐section of a beam.
4. Figure 2.4 A simply supported beam with a concentrated load.
5. Figure 2.5 Testing diagram of body bending stiffness.
6. Figure 2.6 Tested deflection curves of a vehicle body.
7. Figure 2.7 A group of BIW bending stiffness values for economy sedans with windshields.
8. Figure 2.8 A group of BIW bending stiffness values for mid‐sized sedans with windshields.
9. Figure 2.9 A group of BIW bending stiffness values for SUVs with windshields.
10. Figure 2.10 A twisted beam and a small segment dx.
11. Figure 2.11 Testing diagram of body torsional stiffness.
12. Figure 2.12 Measured twisted angles of a body.
13. Figure 2.13 A group of BIW torsional stiffness values for economy sedans with windshields.
14. Figure 2.14 A group of BIW torsional stiffness values for mid‐sized sedans with windshields.
15. Figure 2.15 A group of BIW torsional stiffness values for SUVs with windshields.
16. Figure 2.16 A closed‐loop structure.
17. Figure 2.17 Open‐loop structures: (a) disconnected at the end; (b) disconnected at a longitudinal beam; (c) disconnected at a cross member.
18. Figure 2.18 A floor structure: (a) open loop; and (b) closed loop.
19. Figure 2.19 Influence of number of beams on body stiffness. (a) Two cross members. (b) Three cross members.
20. Figure 2.20 (a) Base frame structure; (b) widened frame structure.
21. Figure 2.21 Reinforced beams to support shotguns: (a) one cross frame; (b) a V‐beam.
22. Figure 2.22 Several cross‐section shapes of body frames and pillars: (a) cross‐section of A‐pillar; (b) cross‐section of rocker frame; (c) cross‐section of front roof cross member; (d) cross‐section of rear roof cross member; (e) cross‐section of floor cross member.
23. Figure 2.23 A cross‐section with two closed loops.
24. Figure 2.24 A closed cross‐section and open cross‐section.
25. Figure 2.25 (a) A closed circular cross‐section; (b) an open circular cross‐section.
26. Figure 2.26 Joints of a sedan at A‐pillar, B‐pillar, and C‐pillar.
27. Figure 2.27 Joints of an SUV at A‐pillar, B‐pillar, C‐pillar, and D‐pillar.
28. Figure 2.28 A system consisting of two beams and a joint.
29. Figure 2.29 A joint finite element model.
30. Figure 2.30 Anatomy diagram of a B2 joint.
31. Figure 2.31 Structural foam installed at a joint.
32. Figure 2.32 Structural adhesives used on a body.
33. Figure 2.33 A comparison of FRFs for two bodies with and without adhesives.
34. Figure 2.34 Comparison of BIW stiffness with and without windshields: (a) bending stiffness; (b) torsional stiffness.
35. Figure 2.35 A system subjected to general forces and induced general deformation.
36. Figure 2.36 Bending strain energy distribution on the frames and joints of a BIW when it is subjected to a static bending load.
37. Figure 2.37 Torsional strain energy distribution on the frames and joints of a BIW when it is subjected to a static torque.
38. Figure 2.38 (a) Cantilever beam; (b) first bending mode; (c) second bending mode.
39. Figure 2.39 First bending mode of a BIW.
40. Figure 2.40 First torsional mode of a BIW.
41. Figure 2.41 Modal frequencies of a BIW’s first bending modes for (a) economy sedans, (b) mid‐sized sedans, and (c) SUVs.
42. Figure 2.42 Modal frequencies of a BIW’s first torsional modes for (a) economy sedans, (b) mid‐sized sedans, and (c) SUVs.
43. Figure 2.43 Modal testing system for a vehicle body.
44. Figure 2.44 A tested body is hung by soft rubber ropes.
45. Figure 2.45 A tested body is supported by soft air cushions.
46. Figure 2.46 An excitation location where an exciter is mounted.
47. Figure 2.47 Distribution of response points for BIW modal testing.
48. Figure 2.48 Accelerometer distribution on a dash panel.
49. Figure 2.49 A transfer function between an acceleration and an input force.
50. Figure 2.50 (a) The body first bending mode; (b) the body first torsional mode.
51. Figure 2.51 First bending mode (a) and first torsional mode (b) of a body calculated by finite element analysis.
52. Figure 2.52 Excitation relationship between body modes and rotary machines.
53. Figure 2.53 Bending stiffness target values for frames and joints of a body.
54. Figure 2.54 Torsional stiffness target values for frames and joints of a body.
55. Figure 2.55 Influence of a battery placed at different locations on body bending modal frequency: (a) at front end; (b) on top of front tire; (c) at behind of rear seat.
56. Figure 2.56 A power plant used as a body damper.
57. Figure 2.57 A cooling module used as a body damper.
Chapter 03
1. Figure 3.1 Classification of local body structures.
2. Figure 3.2 An acoustic cavity of a sedan.
3. Figure 3.3 Some secondary beams of a body.
4. Figure 3.4 Pipes passing through a dash panel.
5. Figure 3.5 Floor and systems installed on the floor.
6. Figure 3.6 Interior idle noise comparison for rigid connection and soft connection between fuel pipe and floor.
7. Figure 3.7 A roof and supporting beams.
8. Figure 3.8 A huge interior booming at 46 Hz in a vehicle driven on a rough road.
9. Figure 3.9 First acoustic cavity mode of a sedan.
10. Figure 3.10 A rectangular plate.
11. Figure 3.11 Modal shapes for the first 10 modes of a simply supported rectangular plate.
12. Figure 3.12 Point source and sound radiation.
13. Figure 3.13 Sound radiation of a rectangular plate surrounded by infinite baffles.
14. Figure 3.14 Analogous comparison between a dash panel and a speaker. (a) Vibration of dash panel. (b) Vibration of speaker membrane.
15. Figure 3.15 Third acoustic cavity mode of a vehicle body.
16. Figure 3.16 An FE model for a body acoustic cavity.
17. Figure 3.17 First five acoustic cavity modes for a body cavity without seats. (a) First longitudinal mode. (b) Second longitudinal mode. (c) First transverse mode. (d) Intertwined mode. (e) Complex mode.
18. Figure 3.18 Microphones knotted onto a bar.
19. Figure 3.19 Microphone array inside a vehicle.
20. Figure 3.20 Volume velocity source.
21. Figure 3.21 A tested first acoustic cavity mode of a body.
22. Figure 3.22 An FE model of a cavity including seats.
23. Figure 3.23 First five modes of the body cavity including the seats. (a) First longitudinal mode. (b) Second longitudinal mode. (c) First transverse mode. (d) Intertwined mode. (e) Complex mode.
24. Figure 3.24 A rectangular box.
25. Figure 3.25 Body panel vibration and sound radiation to passenger compartment.
26. Figure 3.26 Transfer processing of panel vibration to sound at the occupant’s ears.
27. Figure 3.27 Volume sound source and panel radiation sound source inside an enclosed space.
28. Figure 3.28 Overall interior sound pressure and each panel’s contributions.
29. Figure 3.29 A roof is further divided into small blocks.
30. Figure 3.30 Contributions to the 75 Hz booming by all blocks, including positive, zero, and negative contributions.
31. Figure 3.31 Window measurement method: (a) body panel is covered; (b) one area is opened.
32. Figure 3.32 A sound intensity probe.
33. Figure 3.33 Position relationship between a sound source and the probe.
34. Figure 3.34 A schematic diagram of a probe passing through the sound source.
35. Figure 3.35 Schematic diagram of measuring a body panel’s vibration by laser.
36. Figure 3.36 Vibration responses of one side of a body, as measured by laser.
37. Figure 3.37 A sound source surface and a microphone array surface.
38. Figure 3.38 A microphone array is used to test the sound radiation of a vehicle body.
39. Figure 3.39 Sound source distribution of the body at 192 Hz.
40. Figure 3.40 Configurations of planar array beamforming: (a) rectangular array, (b) circular array, (c) spiral array, (d) random array.
41. Figure 3.41 Spherical array beamforming.
42. Figure 3.42 A spherical array placed inside a vehicle to test interior noise.
43. Figure 3.43 Display of the tested interior noise.
44. Figure 3.44 (a) A beam without damping and its motion, and (b) a beam with damping and its motion.
45. Figure 3.45 A single DOF system with damping.
46. Figure 3.46 Damped oscillation of underdamped free vibration system.
47. Figure 3.47 A typical curve of Young’s modulus and loss factor varying with temperature for a viscoelastic material.
48. Figure 3.48 Optimal temperature range for (a) a free damping structure and (b) a constrained damping structure.
49. Figure 3.49 Young’s modulus and loss factor of a typical viscoelastic material varying with frequency.
50. Figure 3.50 An active damping structure.
51. Figure 3.51 Configurations of damping materials.
52. Figure 3.52 Free damping structure.
53. Figure 3.53 Constrained damping structure.
54. Figure 3.54 A loss factor curve for a free damping structure varying with the ratio of damping layer thickness (H₂) and steel plate thickness (H₁).
55. Figure 3.55 Schematic diagram of a damping material test.
56. Figure 3.56 Resonant frequency and lower and upper frequencies on a transfer function.
57. Figure 3.57 Foil layers used on (a) a door and (b) a roof.
58. Figure 3.58 Application of expandable damping sheets (a) on the vehicle floor, (b) on a wheelhouse, and (c) on the console.
59. Figure 3.59 Application of damping coating.
60. Figure 3.60 (a) A conventional dash panel; (b) a composite damping dash panel.
61. Figure 3.61 Two pieces of composite damping plate are attached on two locations of a dash panel.
62. Figure 3.62 Comparison of (a) vibration on a dash panel and (b) interior noise between a steel panel and composite damping panel.
63. Figure 3.63 Influence of stiffness on transfer functions between (a) displacement, (b) velocity, and (c) acceleration and input force.
64. Figure 3.64 Flat plate and reinforced plates. (a) Flat plate. (b) Stepped plate. (c) Fluted plate. (d) Bead plate. (e) Curved plate. (f) Plate with supporting beams. (g) Plate with reinforcement adhesives.
65. Figure 3.65 Square flat plate and stiffened plates. (a) Flat plate. (b) Bead plate. (c) Cross‐bead plate. (d) Curved plate.
66. Figure 3.66 First five modes for a (a) flat plate, (b) bead plate, (c) cross‐bead plate, and (d) curved plate.
67. Figure 3.67 Excitation point and response point on a plate.
68. Figure 3.68 Transfer functions between velocity and force for a flat plate, bead plate, cross‐bead plate, and curved plate.
69. Figure 3.69 Radiated sound pressure levels for a flat plate, bead plate, cross‐bead plate, and curved plate.
70. Figure 3.70 (a) A few beads on a panel surface; (b) many beads punched on a panel surface.
71. Figure 3.71 Beads punched on body panels. (a) Beads on floor. (b) Beads on dash panel. (c) Beads on rear package tray.
72. Figure 3.72 Arc‐shaped body panels. (a) Wheelhouse. (b) Luggage trunk.
73. Figure 3.73 Supporting plates added on the internal surfaces of (a) an engine hood, (b) a trunk lid, and (c) a rear side panel.
74. Figure 3.74 Supporting beams on the internal side of outer body panels: (a) side‐impact beam on the internal surface of an outer door panel; (b) supporting beams on a roof.
75. Figure 3.75 Structure of reinforcement adhesive.
76. Figure 3.76 Reinforcement adhesive used on the internal surface of an outer door panel.
77. Figure 3.77 Reinforcement adhesives pasted on a roof and wheelhouse.
78. Figure 3.78 Comparison of interior sound pressures with and without reinforcement adhesives.
79. Figure 3.79 Transfer functions between (a) displacement, (b) velocity, and (c) acceleration and input force for different masses.
80. Figure 3.80 Two masses of 1.5 kg each are added to a trunk lid.
81. Figure 3.81 Comparison of the interior sound pressure level with and without masses.
82. Figure 3.82 Tested body modal shape at 53 Hz.
83. Figure 3.83 A 2 kg mass mounted on a rear roof bow.
84. Figure 3.84 Comparison of interior sound pressure levels with and without mass.
85. Figure 3.85 A dynamic damper and a primary system.
86. Figure 3.86 Transmissibility of primary mass response and base input with and without a dynamic damper.
87. Figure 3.87 Comparison of interior sound pressure for three cases: the original case, with dynamic dampers, and with masses.
88. Figure 3.88 Engine mount bracket: (a) low modal frequency; (b) high modal frequency.
89. Figure 3.89 (a) Cantilever beam; (b) cantilever beam with supporter.
90. Figure 3.90 Two connection methods between steering CCBs and A‐pillars: (a) with two connecting points, and (b) with three connecting points.
91. Figure 3.91 Mounting points of engine brackets: (a) straight line distribution, and (b) triangular distribution.
92. Figure 3.92 A steering system.
93. Figure 3.93 (a) A steering shaft system. (b) A CCB system.
94. Figure 3.94 Structure of a steering shaft system.
95. Figure 3.95 A CCB system.
96. Figure 3.96 A dynamic damper installed in a steering wheel.
97. Figure 3.97 Seat structure: (a) outside structure, (b) interior structure.
98. Figure 3.98 Accelerometer layout for modal testing of the seatback. (a) Frame covered by foams; (b) exposed metal frame.
99. Figure 3.99 Modal shapes of a seatback: (a) first longitudinal bending mode; (b) first lateral bending mode.
100. Figure 3.100 Two seatback frame structures: (a) weak structure, (b) strong structure.
101. Figure 3.101 Joint structure between backrest frame and seat cushion frame. (a) Single adjuster; (b) double adjusters.
102. Figure 3.102 Acceleration sensitivity of the human body in a vertical direction.
103. Figure 3.103 A vibration platform and an installed seat.
104. Figure 3.104 Transfer functions between a seat cushion and platform for a luxury vehicle seat.
105. Figure 3.105 Transfer functions of a typical sports vehicle seat.
Chapter 04
1. Figure 4.1 Two transfer paths of airborne noise into vehicle interior.
2. Figure 4.2 Frequency distribution of a typical interior noise.
3. Figure 4.3 Holes and apertures on a vehicle body: (a) holes on dash panel; (b) hole on mirror supporter; (c) holes on spare tire floor.
4. Figure 4.4 Manufacturing process holes on floor.
5. Figure 4.5 An error‐state hole at a junction area of three panels.
6. Figure 4.6 Relationship between STLs with different opening rates and without holes.
7. Figure 4.7 Influence of opening holes on STL.
8. Figure 4.8 Receiver of an ultrasonic leak detector.
9. Figure 4.9 A blower and a tested body are connected by a flexible pipe.
10. Figure 4.10 A leakage test device: (a) throttle, (b) blower, (c) speed meter, (d) controller, (e) pressure recorder, (f) flexible pipe.
11. Figure 4.11 A pipe passing through a dash panel and single‐layer sealing.
12. Figure 4.12 Improved sound insulation: (a) single ring with increased thickness; (b) two rings form double‐layer insulation.
13. Figure 4.13 Vibration comparison on a dash panel for two cases in which the hardness of the isolation rubbers between the compressor pipe and panel is different.
14. Figure 4.14 Sealing methods for manufacturing process holes: (a) patch, (b) plug, (c) thermoforming material.
15. Figure 4.15 Sealing between two metal sheets: (a) sheets of the same length; (b) sheets of different lengths.
16. Figure 4.16 A groove for holding welding adhesive.
17. Figure 4.17 A digital structure of shifter cable and selection cable passing through a dash panel.
18. Figure 4.18 A DMU diagram of draining holes on a door.
19. Figure 4.19 A DMU diagram of an intersection of three sheets on a wheelhouse.
20. Figure 4.20 Incident wave, absorbed wave, and reflected wave.
21. Figure 4.21 Structure of porous sound absorptive material.
22. Figure 4.22 Typical curve of sound absorption coefficient for porous materials.
23. Figure 4.23 Relationship between sound absorption coefficient and flow resistance.
24. Figure 4.24 Sound absorption coefficients for the same material with different thicknesses.
25. Figure 4.25 Relationship between sound absorption coefficient and increase in thickness.
26. Figure 4.26 Relationship between sound absorption coefficient and the density of glass wool with the same thickness.
27. Figure 4.27 Relationship between volume density and sound absorption coefficient.
28. Figure 4.28 Relationship between temperature and sound absorption coefficient.
29. Figure 4.29 Resonant sound absorption structure.
30. Figure 4.30 Helmholtz resonator.
31. Figure 4.31 Engine heat shield with perforated aluminum foil.
32. Figure 4.32 Sound absorption coefficient comparison for heat shields with and without perforated aluminum foil.
33. Figure 4.33 Diagram of the definition of reverberation time.
34. Figure 4.34 A diagram of sound absorption coefficient measurement using an impedance tube.
35. Figure 4.35 A diagram of the two microphone impedance tube measurement method.
36. Figure 4.36 Incident wave, reflected wave, and transmitted wave.
37. Figure 4.37 Relationship between STL and frequency.
38. Figure 4.38 Relationship between mass and STL for a single plate.
39. Figure 4.39 (a) A single plate; (b) a composite plate.
40. Figure 4.40 Two separated plates.
41. Figure 4.41 A double‐plate sound insulation structure.
42. Figure 4.42 STL of a double‐plate sound insulation system.
43. Figure 4.43 Testing diagram of the reverberation chamber–reverberation chamber method.
44. Figure 4.44 Testing diagram of the reverberation chamber–anechoic chamber method.
45. Figure 4.45 Impedance tube method for measuring the sound insulation coefficient.
46. Figure 4.46 Sound package materials and structures in a vehicle body.
47. Figure 4.47 Application areas of absorptive materials on a vehicle body.
48. Figure 4.48 An engine hoodliner.
49. Figure 4.49 Noise comparison above an engine hood with and without a hoodliner during idling.
50. Figure 4.50 Interior noise comparison with and without the hoodliner in the WOT condition.
51. Figure 4.51 Sound absorption structures freely distributed or without fixed shapes: (a) inside A‐pillar; (b) inside door trim; (c) inside rear package tray.
52. Figure 4.52 A section of a roof structure.
53. Figure 4.53 Interior noise comparison with and without headliner.
54. Figure 4.54 Anatomical diagram of the surface and internal acoustic structure of a seat.
55. Figure 4.55 Percentage of sound absorption for different components of a vehicle body.
56. Figure 4.56 Interior noise comparison with and without seats for a vehicle cruising at 120 km h⁻¹.
57. Figure 4.57 Sound absorption comparison for three different surface materials (fabric, leather, and perforated leather) of a seat with the same structure and same internal material.
58. Figure 4.58 Combinations of sound absorption parts and sound insulation parts.
59. Figure 4.59 Propagation processing of a sound wave in a sound absorption material and a sound insulation material.
60. Figure 4.60 Schematic diagram of a dash panel and dash mat.
61. Figure 4.61 Interior sound pressure comparison with and without dash mat for a vehicle during acceleration.
62. Figure 4.62 Contact between a dash mat and dash panel: (a) good contact; (b) poor contact.
63. Figure 4.63 A typical carpet sound package structure.
64. Figure 4.64 Interior noise comparison with and without floor sound package for a vehicle during acceleration.
65. Figure 4.65 STL of two pieces of glass with thicknesses of 4 and 5 mm.
66. Figure 4.66 A PVB laminated glass structure.
67. Figure 4.67 Comparison of STL between pieces of PVB laminated glass and ordinary glass with the same thickness.
68. Figure 4.68 Tube and fluid: (a) unblocked tube; (b) blocked tube.
69. Figure 4.69 A sound wave propagates in tubes.
70. Figure 4.70 Hollow tubes of pillars and beams: (a) A‐pillar; (b) door frame.
71. Figure 4.71 Several locations inside beams and pillars are blocked by baffles.
72. Figure 4.72 Volume comparison of a baffle (a) before and (b) after baking.
73. Figure 4.73 A baffle supported by a bracket is placed at the lower end of a B‐pillar.
74. Figure 4.74 A typical response spectrum of a vehicle’s interior noise and vibration.
75. Figure 4.75 A coupled system consisting of two subsystems.
76. Figure 4.76 A big system consisting of N subsystems.
77. Figure 4.77 Solid couplings: (a) point coupling, (b) line coupling, (c) surface coupling.
78. Figure 4.78 Coupling between a rod and a plate.
79. Figure 4.79 Test layout to measure the loss factor of the spare tire well surface.
80. Figure 4.80 Loss factors of five tested points and average loss factor.
81. Figure 4.81 Sound pressure testing outside a body.
82. Figure 4.82 SEA model of a body subsystem structure.
83. Figure 4.83 An exterior model (a) and interior model (b) of a body cavity model.
84. Figure 4.84 Interior noise comparison between measured value and SEA predicted value.
85. Figure 4.85 Cavity model of a dash panel.
86. Figure 4.86 STL comparison between the SEA calculated value and measured value for a dash panel.
Chapter 05
1. Figure 5.1 Relationship between input and output of a system.
2. Figure 5.2 Transfer function of a single degree of freedom system.
3. Figure 5.3 Main attached points on a body.
4. Figure 5.4 External excitation – flexible element – body.
5. Figure 5.5 Flexible elements used to connect other systems and the body.
6. Figure 5.6 Main noise source excitation points.
7. Figure 5.7 Human body response points.
8. Figure 5.8 Transmission process of “Excitation−Transfer Path−Occupant.”
9. Figure 5.9 Vibration transfer processing of path i.
10. Figure 5.10 Transfer processing of N vibration sources to the interior vibration.
11. Figure 5.11 Transfer processing of the ith vibration source to the interior noise.
12. Figure 5.12 Transfer processing of the N vibration sources to the interior noise.
13. Figure 5.13 Transfer processing of the jth noise source to the interior.
14. Figure 5.14 Transfer processing of the M noise sources to the interior.
15. Figure 5.15 Overall interior noise is summation of the structural‐borne noise and the airborne noise.
16. Figure 5.16 Overall interior sound pressure, overall structural‐borne noise, overall airborne noise, and the noise contribution by each path for a vehicle at WOT condition.
17. Figure 5.17 Relationship among speed, frequency, and order.
18. Figure 5.18 Interior booming generated by resonance between an engine excitation and a mounting bracket at 280 Hz.
19. Figure 5.19 A power plant internal driveshaft system.
20. Figure 5.20 An external driveshaft system.
21. Figure 5.21 Schematic diagram of an engine and a transmission.
22. Figure 5.22 A color map of a vehicle interior noise and two gear‐meshing whines.
23. Figure 5.23 Backlash between a pair of freely rotating gears.
24. Figure 5.24 Color map of rattle noise: (a) with rattle (b) without rattle.
25. Figure 5.25 A Cardan joint.
26. Figure 5.26 Diagram of second‐order motion.
27. Figure 5.27 Comparison of interior sound pressure level on a smooth road and rough road.
28. Figure 5.28 Interior booming at 232 Hz generated by resonance between tire cavity acoustic mode and suspension mode.
29. Figure 5.29 Orders of rotary machines on an engine.
30. Figure 5.30 A dynamic stiffness curve for a single DOF.
31. Figure 5.31 Excitation points and response points for a multi‐DOF system or a continuous system.
32. Figure 5.32 Reference values for body driving point dynamic stiffness.
33. Figure 5.33 Reference values for body acceleration impedance.
34. Figure 5.34 Tested acceleration impedances and reference lines of dynamic stiffness.
35. Figure 5.35 IPI and driving point dynamic stiffness.
36. Figure 5.36 Two beams: (a) opening section, (b) closed section.
37. Figure 5.37 A reinforced bracket is added to an open‐section beam.
38. Figure 5.38 IPI comparison for open‐section beam and reinforced beam.
39. Figure 5.39 A series connection of two springs.
40. Figure 5.40 Transfer of vibrational flow from engine excitation to steering wheel by three paths.
41. Figure 5.41 Vibration at one source generating responses on steering wheel in three directions.
42. Figure 5.42 Diagrammatic sketch of vibration−vibration sensitivity testing.
43. Figure 5.43 A tested vibration−vibration sensitivity curve.
44. Figure 5.44 A color‐strip map for a vibration−vibration sensitivity path.
45. Figure 5.45 A color map of vibration−vibration sensitivities.
46. Figure 5.46 Transfer processing of engine mount vibration to interior noise.
47. Figure 5.47 Diagrammatic sketch of the sound−vibration sensitivity testing.
48. Figure 5.48 Sound−vibration sensitivity curve.
49. Figure 5.49 Sound−vibration sensitivity curves for multi‐paths.
50. Figure 5.50 Four points on the underbody of a vehicle cross section.
51. Figure 5.51 First bending mode of a body and three excitation points.
52. Figure 5.52 (a) A constant section beam; (b) a beam with smaller section in the middle.
53. Figure 5.53 Response comparison of two different section beams: (a) time‐domain, (b) frequency‐domain.
54. Figure 5.54 Connections between subframes and body: (a) rigid‐connected subframe; (b) flexible‐connected subframe.
55. Figure 5.55 Comparison of sound‐vibration sensitivities for two subframes (rigid‐connected subframe, and flexible‐connected subframe) subjected to the same excitation.
56. Figure 5.56 Tested vibration−vibration sensitivity and target line at idling.
57. Figure 5.57 Tested sound−vibration sensitivity curves and the target line.
58. Figure 5.58 Diagram of noise reduction measurement in a reverberation chamber.
59. Figure 5.59 Sound pressure levels of five different locations outside the vehicle inside the reverberation chamber.
60. Figure 5.60 Noise reductions at different locations inside the body.
61. Figure 5.61 Noise reduction measurement inside the anechoic room.
62. Figure 5.62 Noise reductions between the simulator six surfaces and the interior.
63. Figure 5.63 Volume velocity source.
64. Figure 5.64 Tested acoustic transfer functions of a car.
65. Figure 5.65 Benchmarked noise reductions between the exhaust orifice noise and the interior noise, and the set target.
Chapter 06
1. Figure 6.1 Relationship between vehicle speed and engine noise, road noise, and wind noise.
2. Figure 6.2 Monopole sound source.
3. Figure 6.3 Dipole sound source.
4. Figure 6.4 Quadrupole sound source.
5. Figure 6.5 An ideal streamlined object.
6. Figure 6.6 A rectangular object with an arc angle.
7. Figure 6.7 A rectangular object.
8. Figure 6.8 Airflow field distribution of a passenger sedan.
9. Figure 6.9 Aspiration noise development procedure by outside airflow moving into interior through an aperture.
10. Figure 6.10 Inside airflow moving toward to outside.
11. Figure 6.11 A moving vehicle with an opening sunroof.
12. Figure 6.12 Analogy between a body cavity (a) and a Helmholtz resonator (b).
13. Figure 6.13 Analogy between a Helmholtz resonator and a mass‐spring system (a) Helmholtz resonator; (b) Equivalent mass‐spring system; (c) single degree of freedom mass‐spring system.
14. Figure 6.14 A deflector added at front edge of the sunroof.
15. Figure 6.15 A small cavity in area of the doors, the B pillar and the seals.
16. Figure 6.16 Types of small cavities on body surface (a) wide opening and shallow depth cavity, (b) wide opening and deep depth cavity, (c) narrow opening and deep depth cavity, (d) Helmholtz resonator.
17. Figure 6.17 Control of the cavity in B‐pillar region: (a) filed, (b) covered.
18. Figure 6.18 Structural borne paths of wind noise.
19. Figure 6.19 Airborne paths of wind noise.
20. Figure 6.20 Noise sources and transfer paths of wind noise.
21. Figure 6.21 Transitions of body interfaced surfaces: (a) longitudinal section; (b) lateral section.
22. Figure 6.22 Ideal streamlined body styling: (a) longitudinal section; (b) lateral section.
23. Figure 6.23 Local structures of grilles and hoods for two vehicles.
24. Figure 6.24 Airflow moving through grille gaps.
25. Figure 6.25 Airflow at area between front windshield and engine hood.
26. Figure 6.26 Engine hood rear end is designed as a tilted arc.
27. Figure 6.27 A deflector installed in the front of wiper.
28. Figure 6.28 A transition plate between engine hood and windshield.
29. Figure 6.29 Airflow around A pillar: (a) side view, (b) a section view.
30. Figure 6.30 Airflow in side mirror area.
31. Figure 6.31 Outside cavity in A pillar area, (a) large margin; (b) small margin.
32. Figure 6.32 Transitions between surface and surface in A pillar area.
33. Figure 6.33 Transition between front windshield and A pillar: (a) on the same spatial surface, (b) deep offset.
34. Figure 6.34 Airflow in area of roof, rear windshield and trunk lid.
35. Figure 6.35 Seal on back of trunk lid.
36. Figure 6.36 Appendages on underbody.
37. Figure 6.37 A underbody spoiler (air dam).
38. Figure 6.38 Interior noise comparison between with and without a belly pan cover.
39. Figure 6.39 Relative positions between tires and body.
40. Figure 6.40 Interior noise comparison with and without mirror.
41. Figure 6.41 A side mirror structure.
42. Figure 6.42 Outside structure and dimension of a side mirror.
43. Figure 6.43 Local design of mirror surface.
44. Figure 6.44 A sail and triangular body metal sheet.
45. Figure 6.45 A socket on the triangle metal sheet and a plug on the sail.
46. Figure 6.46 Two working modes for a sunroof: (a) retracted mode and (b) vented mode.
47. Figure 6.47 A sunroof deflector.
48. Figure 6.48 Interior noise comparison for a vehicle cursing at 80 km h⁻¹ with and without a deflector.
49. Figure 6.49 Castellated sunroof deflector.
50. Figure 6.50 Parameters on the castellated sunroof deflector.
51. Figure 6.51 Sunroof in vented mode: (a) without side shields; (b) with side shields.
52. Figure 6.52 Antenna: (a) cylinder shape; (b) spiral shape.
53. Figure 6.53 Interior noise comparison for a vehicle with and without an antenna.
54. Figure 6.54 Luggage rack.
55. Figure 6.55 Circular cross section of a rack bar.
56. Figure 6.56 An elliptical cross section of rack bar with a nub.
57. Figure 6.57 Three designs of door handles: (a) protruding handle; (b) handle with streamlined shape, (c) flush handle.
58. Figure 6.58 Interior noise comparison for a vehicle at original condition and body tapped condition.
59. Figure 6.59 Two contacted parts: (a) at standstill condition; (b) after moving.
60. Figure 6.60 Geometry relationship of a body, a door and a seal at standstill condition.
61. Figure 6.61 (a) Seal is compressed; (b) seal is not compressed.
62. Figure 6.62 Primary seal installed on door.
63. Figure 6.63 Secondary seal installed on body.
64. Figure 6.64 Auxiliary seals on body.
65. Figure 6.65 Seals only installed on door.
66. Figure 6.66 Primary seal installed on body and auxiliary seals on doors.
67. Figure 6.67 A primary seal on door, a secondary seal on body and auxiliary seals on door.
68. Figure 6.68 A primary seal on door, a secondary seal on body and auxiliary seals on both door and body.
69. Figure 6.69 Compression Load Deflection (CLD) of a seal.
70. Figure 6.70 (a) Section of a single bulb seal; (b) CLD curve.
71. Figure 6.71 (a) Section of a double bulb seal; (b) CLD curve.
72. Figure 6.72 Background noise levels of some wind tunnels at different wind speed (a) Inflow (b) Outflow.
73. Figure 6.73 A schematic diagram of a wind tunnel (top view).
74. Figure 6.74 Angle between vehicle and airflow: (a) 0°; (b) angle α.
75. Figure 6.75 Beamforming is used to measure wind noise.
76. Figure 6.76 Diagram of body surface sound measurement by an parabolic mirror.
77. Figure 6.77 Traditional microphone array on a specially made body surface.
78. Figure 6.78 Surface microphone.
79. Figure 6.79 A vehicle interior noise comparison for quietest body, sealed body, and original body.
80. Figure 6.80 Calculated wind noise distribution in the mirror area.
Chapter 07
1. Figure 7.1 Cartoon pictures of a violin and a tractor.
2. Figure 7.2 Ear structure.
3. Figure 7.3 Hearing threshold curve.
4. Figure 7.4 Four persons leaning against a wall.
5. Figure 7.5 Equal loudness contours.
6. Figure 7.6 Relationship between the loudness and the sound pressure level.
7. Figure 7.7 A sound pressure level (a) and corresponding specific loudness (b).
8. Figure 7.8 Two sounds with the same sound pressure level but different sharpness: (a) low sharpness; (b) high sharpness.
9. Figure 7.9 Two pure tone signals: (a) time domain; (b) frequency domain.
10. Figure 7.10 Superimposed signal of two signals with different frequencies and magnitudes.
11. Figure 7.11 Superimposition of two signals with the same frequency but different magnitudes.
12. Figure 7.12 Superimposition of two signals with the same magnitude but different frequencies.
13. Figure 7.13 Fluctuation strength varying with frequency.
14. Figure 7.14 A prominence tonality within a Bark band.
15. Figure 7.15 Prominent sound within a Bark bandwidth compared with adjacent bandwidths.
16. Figure 7.16 AI weighting coefficient.
17. Figure 7.17 A white noise masked threshold.
18. Figure 7.18 Masked threshold for 60 dB sound pressure levels at each narrowband frequency.
19. Figure 7.19 Masking curves for different SPLs at 1000 Hz center frequency.
20. Figure 7.20 A spider diagram of a power train sound quality including subjective description and scoring.
21. Figure 7.21 A sound quality room.
22. Figure 7.22 An artificial head used to measure door closing sound.
23. Figure 7.23 Loudness of closing doors of a series of vehicles.
24. Figure 7.24 Sharpness values of closing doors of a group of vehicles.
25. Figure 7.25 A time‐domain curve of closing door action.
26. Figure 7.26 Time−frequency spectrum of a closing door sound.
27. Figure 7.27 Objective tested loudness and sharpness values and subjective scorings.
28. Figure 7.28 A door structure.
29. Figure 7.29 A door lock structure: (a) lock outside structure, (b) lock main structure, (c) lock internal structure.
30. Figure 7.30 Test setup of lock impact.
31. Figure 7.31 A tested sound in time domain of impact between latch and striker.
32. Figure 7.32 (a) Side‐impact beam, reinforcement adhesive, and (b) damping sheet used on inner side of outer door panel.
33. Figure 7.33 Complicated reinforced structure of an inner panel.
34. Figure 7.34 Over‐slam bumper on the door.
35. Figure 7.35 IPI testing on a striker.
36. Figure 7.36 A tested IPI curve of a striker.
37. Figure 7.37 Design procedure of door closing sound quality.
38. Figure 7.38 Color map of the door closing action: (a) original door; (b) modified door.
39. Figure 7.39 Time domain curve of the door closing action; (a) original door; (b) modified door.
Chapter 08
1. Figure 8.1 (a) Two contacted objects subjected to a normal force and horizontal force; (b) friction force on the contacted surfaces.
2. Figure 8.2 Friction coefficient varying with time.
3. Figure 8.3 Single DOF friction system.
4. Figure 8.4 Friction force decreases with object movement speed increase.
5. Figure 8.5 Squeak testing of a friction pair.
6. Figure 8.6 Squeak sound pressure level varying with temperature.
7. Figure 8.7 Change of squeak sound pressure levels with humidity.
8. Figure 8.8 Change of squeak sound pressure levels with normal pressure.
9. Figure 8.9 Change of squeak sound pressure levels with excitation frequency.
10. Figure 8.10 (a) A moving object hits a standstill surface; (b) two objects impact each other.
11. Figure 8.11 δ function: (a) graph in time domain; (b) graph in frequency domain.
12. Figure 8.12 Graphs of a half‐sine function: (a) in time‐domain; (b) in frequency domain.
13. Figure 8.13 Relationship between body modal frequency and subjective scoring.
14. Figure 8.14 Body frame and four diagonal lines of body closure openings.
15. Figure 8.15 Deformation values of several body closure openings.
16. Figure 8.16 A door‐in‐white: (a) first bending mode; (b) first torsional mode.
17. Figure 8.17 Bending modal frequencies of a group of door‐in‐white: (a) front doors; (b) back doors.
18. Figure 8.18 Torsional modal frequencies of the doors‐in‐white: (a) front doors; (b) back doors.
19. Figure 8.19 An IP overall modal shape.
20. Figure 8.20 Local modes inside the IP: (a) a mode of the glove box; (b) a mode of the ventilation pipe.
21. Figure 8.21 Modes of the instrument panel and the central console mounted on the body.
22. Figure 8.22 Connections between subsystems and the body: (a) IP and body; (b) cross car beam (CCB) and the A pillar.
23. Figure 8.23 Body S&R sensitivity: 1 N force is applied on four body points connected with suspension.
24. Figure 8.24 Body sensitivities at an IP fastener in three directions to left rear suspension excitation.
25. Figure 8.25 Excitation points and response points for whole vehicle response analysis.
26. Figure 8.26 Acceleration in three directions at a fastener inside an IP.
27. Figure 8.27 Photographs of several roads: (a) brick road; (b) cobblestone road; (c) bumper road.
28. Figure 8.28 Road in a special parking lot.
29. Figure 8.29 A vehicle placed on a four‐post simulator.
30. Figure 8.30 NVH stethoscope.
31. Figure 8.31 A door installed on a component S&R bench.
32. Figure 8.32 Accelerometers placed on the body or subsystem surfaces.
33. Figure 8.33 Acceleration power spectral density on the IP surfaces for the four vehicles.
34. Figure 8.34 Comparison of glove surface acceleration power spectral densities with/without rattle.
35. Figure 8.35 Near‐field sounds of the mount with and without the rattle.
36. Figure 8.36 Integration design of a body S&R control.
37. Figure 8.37 Isolation between adjacent components: (a) using fasteners; (b) using isolation material.
38. Figure 8.38 (a) Disorganized arrangement of the wires; (b) a set of bundled wires.
39. Figure 8.39 A section of a component connected by two bolts or fasteners can be regarded as a beam.
40. Figure 8.40 Connections between an IP upper portion and a body by different number of fasteners.
41. Figure 8.41 Wheelhouse consisting of several large flat plates.
42. Figure 8.42 A subjective evaluation rating for three vehicles at high mileages.
43. Figure 8.43 Overall S&R indicators varying with mileage for three vehicles.
Chapter 09
1. Figure 9.1 Development period of a brand‐new vehicle.
2. Figure 9.2 Processing of target setting, execution, and realization.
3. Figure 9.3 Four factors influencing NVH targets.
4. Figure 9.4 Principles and procedures of target setting.
5. Figure 9.5 Interior noise curves at WOT for several best‐sale vehicles in a segment‐market and set target lines.
6. Figure 9.6 Two‐way directions of target cascading.
7. Figure 9.7 NVH milestone checking.

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Noise and Vibration Control in Automotive Bodies