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Human Response to Vibrations and Its Contribution to the Overall Ride Comfort in Automotive Vehicles - A Literature Review
Technical Paper
2020-01-1085
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
The various factors that affect ride comfort, including noise, vibrations and harshness (NVH) have been in focus in many research studies due to an increasing demand in ride comfort in the automotive industry. Vibrations have been highlighted as an important contribution to assess and predict overall ride comfort. The purpose of this paper is to present an approach to explain ride comfort with respect to vibration for the seated occupant based on a systematic literature review of previous fundamental research and to relate these results to the application in the contemporary automotive industry. The results from the literature study show that numerous research studies have determined how vibration frequency, magnitude, direction, duration affect human response to vibration. Also, the studies have highlighted how body posture, age, gender and anthropometry affect the human perception of comfort. An analysis was made of the consistency and inconsistency of the results obtained in the different studies. The deviations of the research results from real-world ride comfort in automotive vehicles were analyzed and divided into three groups: appreciable and consistent with industry results, appreciable and inconsistent with industry results and not appreciable in industrial results. The overall conclusion from this literature study was that there is much information available from laboratory studies regarding human response to vibrations, but there is a lack of studies that take into account all the different parameters that affect the overall ride comfort experience for automotive vehicle occupants.
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Wang, X., Osvalder, A., Höstmad, P., and Johansson, I., "Human Response to Vibrations and Its Contribution to the Overall Ride Comfort in Automotive Vehicles - A Literature Review," SAE Technical Paper 2020-01-1085, 2020, https://doi.org/10.4271/2020-01-1085.Data Sets - Support Documents
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References
- Lyons , G. and Urry , J. Travel Time Use in the Information Age Transp. Res. Part A Policy Pract. 2005 10.1016/j.tra.2004.09.004
- Wallington , T.J. and Wiesen , P. N2O Emissions from Global Transportation Atmos. Environ. 94 258 263 2014
- Greene , D.L. , Baker , H.H. Jr , and Plotkin , S.E. 2010
- Vilhelmson , B. Daily Mobility and the Use of Time for Different Activities. The Case of Sweden GeoJournal 1999 10.1023/A:1007075524340
- Guignard , J. and Vibration , C. . 1965
- Guignard , J.C. 1985
- Hood , W.B. , Murray , R.H. , Urschel , C.W. , Bowers , J.A. , and Clark , J.G. Cardiopulmonary Effects of Whole-Body Vibration in Man J. Appl. Physiol 1966
- Zhang , L. , Helander , M.G. , and Drury , C.G. Identifying Factors of Comfort and Discomfort in Sitting Hum. Factors 1996 10.1518/001872096778701962
- Slater , K. Human Comfort 1 USA Springfield, Ill, CC Thomas 1985
- Keegan , J.J. Alterations of the Lumbar Curve Related to Posture and Seating JBJS 35 589 603 1953
- Sheng , G. Vehicle Noise, Vibration, and Sound Quality SAE 2012
- Corbridge , C. 1987
- Griffin , M.J. and Erdreich , J. Handbook of Human Vibration J. Acoust. Soc. Am. 1991 10.1121/1.401606
- Gillespie , T.D. Fundamentals of Vehicle Dynamics 400 Warrendale, PA Society of Automotive Engineers 1992
- Von , H.E.G. and Coermann , R.R. The Biodynamics of Human Response to Vibration and Impact Rev. Med. Aeronaut. 2 201 203 1961
- Nawayseh , N. Effect of the Seating Condition on the Transmission of Vibration through the Seat Pan and Backrest Int. J. Ind. Ergon. 45 82 90 2015
- Giacomin , J. and Woo , Y.J. Steering System Vibration: Information and Perception Enhancement ATZ Automob. Zeitschrift 107 422 429 2005
- Morioka , M. and Griffin , M.J. Equivalent Comfort Contours for Vertical Vibration of Steering Wheels: Effect of Vibration Magnitude, Grip Force, and Hand Position Appl. Ergon. 40 817 825 2009
- International Standards Organization 1997
- British Standards Institution BS 6841:1987 Guide to Measurement and Evaluation of Human Exposure to Whole-Body Mechanical Vibration and Repeated Shock BSI 1987
- Arnold , J.J. and Griffin , M.J. Equivalent Comfort Contours for Fore-and-Aft, Lateral, and Vertical Whole-Body Vibration in the Frequency Range 1.0 to 10 Hz Ergonomics 61 1545 1559 2018
- Zhou , Z. and Griffin , M.J. Response of the Seated Human Body to Whole-Body Vertical Vibration: Biodynamic Responses to Sinusoidal and Random Vibration Ergonomics 57 693 713 2014
- De Silva , C.W. Human Response to Vibration Vibration Monitoring, Testing, and Instrumentation 2007 641 649
- Morioka , M. and Griffin , M.J. Magnitude-Dependence of Equivalent Comfort Contours for Fore-and-Aft, Lateral and Vertical Whole-Body Vibration J. Sound Vib. 298 755 772 2006
- Jones , A.J. and Saunders , D.J. Equal Comfort Contours for Whole Body Vertical, Pulsed Sinusoidal Vibration J. Sound Vib. 1972 10.1016/0022-460X(72)90785-7
- Shoenberger , R.W. and Harris , C.S. Psychophysical Assessment of Whole-Body Vibration Hum. Factors J. Hum. Factors Ergon. Soc. 1971 10.1177/001872087101300106
- Fothergill , L.C. , Fothehgul , L.C. , and Grifexn , M.J. The Subjective Magnitude of Whole-Body Vibration Ergonomics 20 521 533 1977
- Zheng , G. , Qiu , Y. , and Griffin , M.J. Fore-and-Aft and Dual-Axis Vibration of the Seated Human Body: Nonlinearity, Cross-Axis Coupling, and Associations between Resonances in the Transmissibility and Apparent Mass Int. J. Ind. Ergon. 69 58 65 2019
- Toward , M.G.R. and Griffin , M.J. Apparent Mass of the Human Body in the Vertical Direction: Inter-Subject Variability J. Sound Vib. 330 827 841 2011
- Holmlund , P. , Lundström , R. , and Lindberg , L. Mechanical Impedance of the Human Body in Vertical Direction Appl. Ergon. 31 415 422 2000
- Holmlund , P. and Lundström , R. Mechanical Impedance of the Human Body in the Horizontal Direction J. Sound Vib. 1998 10.1006/jsvi.1998.1593
- Mandapuram , S. , Rakheja , S. , Boileau , P.É. , and Maeda , S. Apparent Mass and Head Vibration Transmission Responses of Seated Body to Three Translational Axis Vibration Int. J. Ind. Ergon. 42 268 277 2012
- Bhiwapurkar , M.K. , Saran , V.H. , and Harsha , S.P. Effects of Posture and Vibration Magnitude on Seat to Head Transmissibility during Exposure to Fore-and-Aft Vibration J. Low Freq. Noise Vib. Act. Control 38 826 838 2019
- Mansfield , N.J. Impedance Methods (Apparent Mass, Driving Point Mechanical Impedance and Absorbed Power) for Assessment of the Biomechanical Response of the Seated Person to Whole-Body Vibration Industrial Health 2005 10.2486/indhealth.43.378
- Kitazaki , S. and Griffin , M.J. A Data Correction Method for Surface Measurement of Vibration on the Human Body J. Biomech. 28 885 890 1995
- Sezgin , A. and Yagiz , N. Analysis of Passenger Ride Comfort MATEC Web of Conferences 2012 1
- Wei , L. and Griffin , M.J. Mathematical Models for the Apparent Mass of the Seated Human Body Exposed to Vertical Vibration J. Sound Vib. 212 855 874 1998
- Zheng , G. , Qiu , Y. , and Griffin , M.J. An Analytic Model of the In-Line and Cross-Axis Apparent Mass of the Seated Human Body Exposed to Vertical Vibration with and without a Backrest J. Sound Vib. 330 6509 6525 2011
- Kitazaki , S. and Griffin , M.J. A Modal Analysis of Whole-Body Vertical Vibration, Using a Finite Element Model of the Human Body J. Sound Vib. 200 83 103 1997
- Cho , H.Y. , Han , M. , Hirao , A. , and Matsuoka , H. Virtual Occupant Model for Riding Comfort Simulation Proc. 12th Int. Model. Conf. Prague, Czech Republic , May 15-17, 2017 132 27 34
- Siefert , A. , Hofmann , J. , Veeraraghavan , A. , and Lu , Y. Numerical Methods for Combined Analysis of Seat and Ride-Comfort SAE Technical Paper 2019-01-0404 2019 https://doi.org/10.4271/2019-01-0404
- Nawayseh , N. and Griffin , M.J. Power Absorbed during Whole-Body Fore-and-Aft Vibration: Effects of Sitting Posture, Backrest, and Footrest J. Sound Vib. 2012 10.1016/j.jsv.2011.08.015
- Huang , Y. and Griffin , M.J. Nonlinearity in Apparent Mass and Transmissibility of the Supine Human Body during Vertical Whole-Body Vibration J. Sound Vib. 324 429 452 2009
- Zhou , Z. and Griffin , M.J. Response of the Seated Human Body to Whole-Body Vertical Vibration: Discomfort Caused by Sinusoidal Vibration Ergonomics 57 714 732 2014
- Basri , B. and Griffin , M.J. Equivalent Comfort Contours for Vertical Seat Vibration: Effect of Vibration Magnitude and Backrest Inclination Ergonomics 2012 10.1080/00140139.2012.678390
- Matsumoto , Y. and Griffin , M.J. Non-Linear Characteristics in the Dynamic Responses of Seated Subjects Exposed to Vertical Whole-Body Vibration J. Biomech. Eng. 124 527 532 2002
- Matsumoto , Y. and Griffin , M.J. Nonlinear Subjective and Biodynamic Responses to Continuous and Transient Whole-Body Vibration in the Vertical Direction J. Sound Vib. 287 919 937 2005
- Whitham , E.M. and Griffin , M.J. The Effects of Vibration Frequency and Direction on the Location of Areas of Discomfort Caused by Whole-Body Vibration Appl. Ergon. 1978 10.1016/0003-6870(78)90084-4
- Griffin , M.J. , Whitham , E.M. , and Parsons , K.C. Vibration and Comfort I: Translational Seat Vibration Ergonomics 25 603 630 1982
- Beard , G.F. and Griffin , M.J. Discomfort during Lateral Acceleration: Influence of Seat Cushion and Backrest Appl. Ergon. 2013 10.1016/j.apergo.2012.11.009
- Fairley , T.E. and Griffin , M.J. The Apparent Mass of the Seated Human Body in the Fore-and-Aft and Lateral Directions J. Sound Vib. 139 299 306 1990
- Nawayseh , N. and Griffin , M.J. Non-Linear Dual-Axis Biodynamic Response to Fore-and-Aft Whole-Body Vibration J. Sound Vib. 282 831 862 2005
- Subashi , G.H.M.J. , Nawayseh , N. , Matsumoto , Y. , and Griffin , M.J. Nonlinear Subjective and Dynamic Responses of Seated Subjects Exposed to Horizontal Whole-Body Vibration J. Sound Vib. 321 416 434 2009
- Wyllie , I.H. and Griffin , M.J. Discomfort from sinusoidal oscillation in the pitch and fore-and-aft axes at frequencies between 0.2 and 1.6 Hz J. Sound Vib . 2009 10.1016/j.jsv.2009.02.018
- Beard , G.F. and Griffin , M.J. Discomfort Caused by Low-Frequency Lateral Oscillation, Roll Oscillation and Roll-Compensated Lateral Oscillation Ergonomics 56 103 114 2013
- Griffin , M.J. , Whitham , E.M. , and Parsons , K.C. Vibration and Comfort: II Rotational Seat Vibration Ergonomics 25 631 644 1982
- Pradko , F. Human Response to Random Vibration Shock Vib. Bull. 34 173 190 1965
- Wyllie , I.H. and Griffin , M.J. Discomfort from Sinusoidal Oscillation in the Roll and Lateral Axes at Frequencies between 0.2 and 1.6Hz J. Acoust. Soc. Am. 2007 10.1121/1.2715654
- Parsons , K.C. and Griffin , M.J. The Effect of the Position of the Axis of Rotation on the Discomfort Caused by Whole-Body Roll and Pitch Vibrations of Seated Persons J. Sound Vib. 1978 10.1016/S0022-460X(78)80066-2
- Rakheja , S. , Stiharu , I. , and Boileau , P.É. Seated Occupant Apparent Mass Characteristics under Automotive Postures and Vertical Vibration Journal of Sound and Vibration 2002 10.1006/jsvi.2001.4249
- Morioka , M. and Griffin , M.J. Magnitude-Dependence of Equivalent Comfort Contours for Fore-and-Aft, Lateral, and Vertical Vibration at the Foot for Seated Persons J. Sound Vib. 2010 10.1016/j.jsv.2010.01.026
- Matsumoto , Y. and Griffin , M.J. Dynamic Response of the Standing Human Body Exposed to Vertical Vibration: Influence of Posture and Vibration Magnitude J. Sound Vib. 1998 10.1006/jsvi.1997.1376
- Huang , Y. and Griffin , M.J. Nonlinear Dual-Axis Biodynamic Response of the Semi-Supine Human Body during Vertical Whole-Body Vibration J. Sound Vib. 312 296 315 2008
- Toward , M.G.R. and Griffin , M.J. Apparent Mass of the Human Body in the Vertical Direction: Effect of Seat Backrest J. Sound Vib. 327 657 669 2009
- Wang , W. , Rakheja , S. , and Boileau , P.É. Effects of Sitting Postures on Biodynamic Response of Seated Occupants under Vertical Vibration Int. J. Ind. Ergon. 2004 10.1016/j.ergon.2004.04.009
- Mansfield , N.J. and Griffin , M.J. Effects of Posture and Vibration Magnitude on Apparent Mass and Pelvis Rotation during Exposure to Whole-Body Vertical Vibration Journal of Sound and Vibration 2002 10.1006/jsvi.2001.4251
- Nawayseh , N. and Griffin , M.J. Non-Linear Dual-Axis Biodynamic Response to Vertical Whole-Body Vibration J. Sound Vib. 268 503 523 2003
- Jang , H.K. and Griffin , M.J. Effect of Phase, Frequency, Magnitude and Posture on Discomfort Associated with Differential Vertical Vibration at the Seat and Feet J. Sound Vib. 229 273 286 2000
- Bohman , K. , Osvalder , A.-L. , Ankartoft , R. , and Alfredsson , S. A Comparison of Seat Belt Fit and Comfort Experience between Older Adults and Younger Front Seat Passengers in Cars Traffic Inj. Prev. 2019 10.1080/15389588.2019.1639159
- Osvalder , A.-L. , Bohman , K. , Lindman , M. , Ankartoft , R. , and Alfredsson , S.
- Ritzel , H. , Amling , M. , Pösl , M. , Hahn , M. , and Delling , G. The Thickness of Human Vertebral Cortical Bone and Its Changes in Aging and Osteoporosis: A Histomorphometric Analysis of the Complete Spinal Column from Thirty-Seven Autopsy Specimens J. Bone Miner. Res. 1997 10.1359/jbmr.1997.12.1.89
- Fairley , T.E. and Griffin , M.J. The Apparent Mass of the Seated Human Body: Vertical Vibration J. Biomech. 1989 10.1016/0021-9290(89)90031-6
- Duarte , M.L.M. , de Araújo , P.A. , Horta , F.C. , Del Vecchio , S. and de Carvalho , L.A.P. Correlation between Weighted Acceleration, Vibration Dose Value and Exposure Time on Whole Body Vibration Comfort Levels Evaluation Saf. Sci. 103 218 224 2018
- Morioka , M. and Griffin , M.J. Absolute Thresholds for the Perception of Fore-and-Aft, Lateral, and Vertical Vibration at the Hand, the Seat, and the Foot J. Sound Vib. 314 357 370 2008
- Bastiaan , J.M. , Green , E. , and Kaye , S. Preliminary Study of Perceived Vibration Quality for Human Hands SAE Int. J. Adv. & Curr. Prac. in Mobility 1 4 1741 1754 2019 https://doi.org/10.4271/2019-01-1522
- Morioka , M. and Griffin , M.J. Frequency Weightings for Fore-and-Aft Vibration at the Back: Effect of Contact Location, Contact Area, and Body Posture Ind. Health 2010 10.2486/indhealth.MSWBVI-05
- Leatherwood , J.D. 1979
- Huang , Y. 2012
- Manninen , O. Studies of combined effects of sinusoidal whole body vibrations and noise of varying bandwidths and intensities on TTS2 in men Int. Arch. Occup. Environ. Health 51 273 288 1983
- Tchernychouk , V. , Rakheja , S. , Stiharu , I. , and Boileau , P.É. Study of Occupant-Seat Models for Vibration Comfort Analysis of Automotive Seats SAE Technical Paper 2000-01-2688 2000 https://doi.org/10.4271/2000-01-2688
- Adam , S.A. and Jalil , N.A.A. Vertical Suspension Seat Transmissibility and SEAT Values for Seated Person Exposed to Whole-body Vibration in Agricultural Tractor Preliminary Study Procedia Engineering 2017 10.1016/j.proeng.2017.03.070
- Daruis , D.D.I. , Deros , B.M. , Nor , M.J.M. , and Hosseini , M. An Integrated Model of Static and Dynamic Measurement for Seat Discomfort Ind. Eng. Manag. Syst. 10 185 190 2011
- Kaderli , F. and Gomes , H.M. Vibration Analysis Based on Health and Comfort Levels on Ride Vehicles International Journal of Vehicle Noise and Vibration 2015 10.1504/IJVNV.2015.075166
- Lin , K.Y. , Hwang , J.R. , Chang , S.H. , Fung , C.P. , and Chang , J.M. System Dynamics and Ride Quality Assessment of Automobile SAE Technical Paper 2006-01-1225 2006 https://doi.org/10.4271/2006-01-1225
- Kaderli , F. and Gomes , H.M. Vibration Analysis Based on Health and Comfort Levels on Ride Vehicles Int. J. Veh. Noise Vib. 11 238 254 2015
- Jayachandran , R. and Krishnapillai , S. Modeling and Optimization of Passive and Semi-Active Suspension Systems for Passenger Cars to Improve Ride Comfort and Isolate Engine Vibration JVC/Journal Vib. Control 2013 10.1177/1077546312445199
- Mansfield , N.J. Localized Vibration at the Automotive Seat-Person Interface the 2001 International Congress and Exhibition on Noise Control Engineering 2001
- Wu , X. , Rakheja , S. , and Boileau , P.É. Distribution of Human-Seat Interface Pressure on a Soft Automotive Seat under Vertical Vibration Int. J. Ind. Ergon. 1999 10.1016/S0169-8141(98)00058-4
- Kilincsoy , U. , Wagner , A. , Vink , P. , and Bubb , H. Application of Ideal Pressure Distribution in Development Process of Automobile Seats Work 2016 10.3233/WOR-162350
- Ajovalasit , M. , Shabani , A. , Tajadura , A. , and Giacomin , J. Affective Reactions to Vibro-Tactile Events: A Case Study in Automotive Applications 8th Int. Conf. Des. Emot. Out Control - Proc 2012 1 11
- GS, P. & MJ, G. Use of Seating Control Exposures to Whole-Body Vibration Human Factors Research Unit Institute of Sound and Vibration Research for the Health and Safety Executive (HSE) 2001
- Bengal , W. Discomfort, Pressure Distribution and Safety in Operator’s Seat - A Critical Review Ergonomics 56 1 16 2013
- Park , S.J. and Kim , C.B. The Evaluation of Seating Comfort by the Objective Measures SAE Technical Paper 970595 1997 https://doi.org/10.4271/970595
- Papaioannou , G. , Voutsinas , A. , Koulocheris , D. , and Antoniadis , I. Dynamic Performance Analysis of Vehicle Seats with Embedded Negative Stiffness Elements Veh. Syst. Dyn. 2019 10.1080/00423114.2019.1617424
- Kolich , M. Automobile Seat Comfort: Occupant Preferences vs. Anthropometric Accommodation Appl. Ergon. 2003 10.1016/S0003-6870(02)00142-4
- Stikeleather , L.F. , Hall , G.O. , and Radke , A.O. Study of Vehicle Vibration Spectra as Related to Seating Dynamics SAE Technical Paper 720001 1972 https://doi.org/10.4271/720001
- Siefert , A. , Pankoke , S. , and Wölfel , H.P. Virtual Optimisation of Car Passenger Seats: Simulation of Static and Dynamic Effects on Drivers’ Seating Comfort Int. J. Ind. Ergon. 38 410 424 2008
- Hostens , I. and Hostens , I. Analysis of Seating during Low Frequency Vibration Exposure Solutions 2004
- Van Niekerk , J.L. , Pielemeier , W.J. , and Greenberg , J.A. The Use of Seat Effective Amplitude Transmissibility (SEAT) Values to Predict Dynamic Seat Comfort J. Sound Vib. 2003 10.1016/S0022-460X(02)00934-3
- Lo , L. , Fard , M. , Subic , A. , and Jazar , R. Characterization of the Automotive Seat/Human Structural Dynamics International Conference on Noise and Vibration Engineering 2012, ISMA 2012, including USD 2012: International Conference on Uncertainty in Structure Dynamics 2012
- Wu , X. , Rakheja , S. , and Boileau , P.É. Study of Human-Seat Interactions for Dynamic Seating Comfort Analysis SAE Technical Paper 1999-01-1303 1999 https://doi.org/10.4271/1999-01-1303
- Rützel , S. , Hinz , B. , and Wölfel , H.P. Modal Description-A Better Way of Characterizing Human Vibration Behavior J. Sound Vib. 2006 10.1016/j.jsv.2006.06.019
- Abbas , W. Optimization of Biodynamic Seated Human Models Using Genetic Algorithms Engineering 2010 10.4236/engineering.2010.29092
- Boileau , P.E. and Rakheja , S. Whole-Body Vertical Biodynamic Response Characteristics of the Seated Vehicle Driver. Measurement and Model Development Int. J. Ind. Ergon. 1998 10.1016/S0169-8141(97)00030-9
- Nawayseh , N. A Mathematical Model of the Apparent Mass of the Human Body under Fore-and-Aft Whole-Body Vibration Int. J. Automot. Mech. Eng. 2016 10.15282/ijame.13.3.2016.7.0297
- van Victor Orlinskiy , S.V. Investigating Car Passenger Well-Being Related to a Seat Imposing Continuous Posture Variation J. Ergon. 5 2015
- Vergara , M. and Page , Á. Relationship between Comfort and Back Posture and Mobility in Sitting-Posture Appl. Ergon. 2002 10.1016/S0003-6870(01)00056-4
- Kamp , I. , Kilincsoy , Ü. , and Vink , P. Chosen Postures during Specific Sitting Activities Ergonomics 54 1029 1042 2011
- Beach , T.A.C. , Parkinson , R.J. , Stothart , J.P. , and Callaghan , J.P. Effects of Prolonged Sitting on the Passive Flexion Stiffness of the in vivo Lumbar Spine Spine J. 2005 10.1016/j.spinee.2004.07.036
- Kyung , G. and Nussbaum , M.A. Specifying Comfortable Driving Postures for Ergonomic Design and Evaluation of the Driver Workspace Using Digital Human Models Ergonomics 52 939 953 2009
- Fiorillo , I. et al. Future Vehicles: The Effect of Seat Configuration on Posture and Quality of Conversation Ergonomics 62 1400 1414 2019
- Bhiwapurkar , M.K. , Saran , V.H. , Harsha , S.P. , Goel , V.K. , and Berg , M. Influence of Mono-Axis Random Vibration on Reading Activity Ind. Health 2010 10.2486/indhealth.MSWBVI-09
- Sundström , J. and Khan , S. Influence of Stationary Lateral Vibrations on Train Passengers’ Difficulty to Read and Write Appl. Ergon. 2008 10.1016/j.apergo.2007.11.009
- Bhiwapurkar , M.K. , Saran , V.H. , and Harsha , S.P. Interference in Writing Performance under Whole-Body Vibration Exposure together with Subject Posture Int. J. Veh. Noise Vib. 2016 10.1504/IJVNV.2016.079055
- Paddan , G.S. et al. The Influence of Seat Backrest Angle on Human Performance during Whole-Body Vibration Ergonomics 2012 10.1080/00140139.2011.634030