1、 _ SAE Technical Standards Board Rules provide that: “This report is published by SAE to advance the state of technical and engineering sciences. The use of this report is entirely voluntary, and its applicability and suitability for any particular use, including any patent infringement arising ther
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4、70 (outside USA) Fax: 724-776-0790 Email: CustomerServicesae.org SAE WEB ADDRESS: http:/www.sae.org SAE values your input. To provide feedback on this Technical Report, please visit http:/www.sae.org/technical/standards/J2531_201604 SURFACE VEHICLE INFORMATION REPORT J2531 APR2016 Issued 2003-11 Rev
5、ised 2011-03Reaffirmed 2016-04 Superseding J2531 MAR2011 Impulse Noise from Automotive Inflatable Devices RATIONALE J2531 has been reaffirmed to comply with the SAE five-year review policy. FOREWORD All acronyms are defined in this document in Section 3.0 “Definitions.“ a. Relationship of the docume
6、nt to other documents The following organizations are involved in setting standards or recommendations for impulse noise analysis: 1. Arbeitskreis (AK) 2. American National Standards Institute (ANSI) 3. National Academy of Sciences/National Research Council, Committee on Hearing, Bioacoustics and Bi
7、omechanics (CHABA). 4. North Atlantic Treaty Organization (NATO) Research Study Group 29 on “Impulse Noise Effects“ 5. U.S. Department of Defense (DOD) 6. U.S. Department of Transportation (DOT) b. History, background, and introductory material. 1. Evolution of Impulse Noise Risk Assessment (a) ca.
8、1960: Research into damage risk criteria for impulse noise centers on occupational exposure from steady state noise. Military research established the threshold for eardrum rupture at 180 dB for an unprotected ear with a free-field sound pressure wave at grazing incidence. (b) 1966: Criterion for st
9、eady state noise published by CHABA Working Group 46 (Kryter et al., 1966) SAE INTERNATIONAL J2531 APR2016 Page 2 of 18 (c) 1968: First criterion specifically for impulse noise published by CHABA based on Coles et al. (1968). This criterion: lowered the tolerable pressure by 5 dB for normal incidenc
10、e of noise wave to ear, lowered the allowable pressure by another 5 dB to protect 95% of population instead of 75% as in Coles et al., established 179 dB peak SPL over 25 microsecond duration as single impulse limit to unprotected ear, accounted for acoustic reflex contraction of middle ear muscles,
11、 and established a correction factor for single impulse exposures by permitting a 10 dB increase in allowable pressure. The method of signal analysis was also specified in this paper using the A and B-durations (see Definitions section). Lacking other tools, passive restraint engineers adopted these
12、 methods and criteria. Typical driver airbag systems produced impulses in the range of 140 to 150 dB. These were considered to be associated with a low risk for PTS. (d) 1969: Classic experiments with human volunteers exposed to automotive airbags performed and reported Nixon (1969). (e) 1971: Bolt,
13、 Beranek, and Newman revised earlier impulse noise criteria to specifically address impulse noise produced by airbag deployment (Allen et al., 1971). Raw pressure-time data was low-pass filtered at 300 Hz for A-duration calculation and high-pass filtered at 300 Hz for B-duration calculation. This me
14、thod analyzes the low and high frequency data as if they act independently on the ear, without interaction between them. (f) 1973: Another classic set of human volunteer experiments conducted by Sommer and Nixon (1973). Volunteers were exposed to low frequency noise (by itself), high frequency noise
15、 (by itself) and low plus high frequency noise acting together. A protective effect of low frequency noise was suggested. (g) 1975: MIL-STD-1474A “Noise Limits for Army Materiel“ first published. This standard established maxima for combinations of peak Sound Pressure Level and B-duration beyond whi
16、ch varying types of hearing protection are required by military personnel. These B-durations are calculated using the wideband pressure-time data collected (with the low and high frequency noise analyzed together in contrast to the BBN method). (h) 1987: SAE J247 (FEB87) Recommended PracticeInstrume
17、ntation For Measuring Acoustic Impulses Within Vehicles. Describes the instrumentation and procedure for measurement of airbag noise in vehicles. (i) 1992: National Academy of Sciences/National Research Council (1992) reports that “The 1968 criterion should not be used for low-frequency impulses suc
18、h as air bags, sonic booms, rapid pressurization etc.“ The NAS decision was primarily based on the fact that the 1968 criterion did not account for the spectral distribution of the energy, the number of impulses, or the temporal spacing of the impulses. (j) 1996: A mathematical model of the feline e
19、ar is reported by Price and Kalb from the US Army Research Lab. The model calculates risk based on a hypothesis that damage to the hair cells in the cochlea correlates to a mathematical function of the number and amplitude of basilar membrane displacements in a manner analogous to mechanical fatigue
20、 of solid materials. (k) 1996: Math model of the feline ear is validated for airbag impulses (Price, Rouhana and Kalb, 1996; Price and Kalb, 1996). The model has a movie function that shows the development of the risk of impulse noise-induced threshold shift as it relates to the impulse noise pressu
21、re-time history. (l) 1997: MIL-STD-1474D “Noise Limits“ a revision of MIL-STD-1474C. This standard continues the use of maxima for combinations of peak Sound Pressure Level and B-duration beyond which varying types of hearing protection are required by military personnel. The limits are referenced t
22、o the Curve X instead of Curve Y and Curve X is reduced by 1.5 dB from MIL-STD-1474B). (m) 1999: The ARL Ear model is extended to a human ear model (Price and Kalb, 1999). SAE INTERNATIONAL J2531 APR2016 Page 3 of 18 (n) 1999: ANSI Working Group S3-32 issued a draft report on the effects of impulse
23、noise“. The group recommended using the 8-hour equivalent energy (LAEQ8) criterion for impulse noise below a peak SPL of 140 dB, and the ARL criterion for impulse noise above a peak SPL of 140 dB. (o) 2001: The ARL Ear Model was reviewed by a Peer Review Panel of the American Institute of Biological
24、 Sciences. The panel concluded that the Ear Model “represents a significant improvement over the Department of Defense Design Criteria Standard: Noise Limits of 12 February 1997 (MIL-STD-1474D).“, that “the model was validated by human exposure data obtained in Albuquerque, New Mexico“, and that “th
25、e HRED model can be used to test potential health hazards associated with impulse noise levels in excess of 140 dB“. 2. Biomechanics of Hearing-Sound travels through the air as pressure waves. The external ear lobe (pinna) channels the sound into the ear canal and to the eardrum (tympanic membrane),
26、 where it is converted into vibrations of the ear ossicles called the malleus, the incus and the stapes (also known as the hammer, anvil, and stirrup). The ossicles are located in the middle ear cavity. The stapes is held in the oval window of the cochlea, or inner ear, by the annular ligament. When
27、 the stapes moves due to vibrations of incoming sound pressure, a pressure wave is transmitted down the fluid of the cochlea. The pressure wave distorts a membrane that runs along the length of the cochlea (basilar membrane). Within the cochleas organ of Corti, thousands of microscopic hairs, embedd
28、ed in hair cells resting on the basilar membrane, move when the basilar membrane is distorted. This causes the hair cells connected to the auditory nerve to generate electrochemical signals, which pass to the hearing centers of the brain, to be interpreted as sound. Hair cells near the base of the c
29、ochlea respond mainly to higher frequencies and those near the apex respond mainly to lower frequencies. 3. Human Biovariability Distinct age populations have different hearing acuity. For example, the elderly typically show distinct changes in hearing from their middle age capability (this is calle
30、d presbycusis45% of Americans over age 75 are affected). The feline subject is a human surrogate with hearing acuity similar to that of people, although it is viewed overall, as having significantly greater acuity than humans. The presence of a middle ear infection can reduce the transmissivity of t
31、he middle ear and lower the effective hearing acuity. It is unknown whether age or illness have any effect on risk of noise-induced hearing loss. 4. Mechanisms of Hearing Loss 1. Blow to the Head-gross mechanical failure of structures, such as fracture of ossicles and tearing of the eardrum. 2. Expo
32、sure to Continuous Noise-long duration (hours, weeks, months) exposures to loud noises, such as a rock concerts, heavy equipment, and pneumatic drills without ear protection. Hearing loss in continuous exposure is believed to be biochemical in nature. 3. Exposure to Impulsive Noise-physical trauma t
33、o the cellular structures of the cochlea. For example, the ARL Ear Model risk algorithm identifies the peaks of the upward displacement of the stapes that put the inner ear tissues in tension where they are most likely to sustain damage. Using the calculated stapes displacement as the driving input
34、to the cochlea, the model calculates the displacement history of the basilar membrane for the duration of the input waveform. Risk is calculated at 23 locations along the basilar membrane. The postulated mechanism of injury in the algorithm is similar to mechanical fatigue of the hair cells in gener
35、al engineering and is calculated as a function of the amplitude of the vibration and the number of cycles of vibration. The output of the ARL model calculation is presented in values called Auditory Risk Units ARU. SAE INTERNATIONAL J2531 APR2016 Page 4 of 18 1. SCOPE New methods are available to as
36、sist in evaluating the risk of impulse noise-induced hearing loss from inflatable devices, for example, airbags and seat belt pretensioners. This document presents some background on impulse noise measurement techniques and assessment criteria. Related information relative to test details, for examp
37、le, preamplifier specifications and filtering methods and criteria, will be discussed in a future recommended practice. 1.1 Purpose This document serves to disseminate information about these tools and techniques to assist the automotive restraint development process. 2. REFERENCES 2.1 Applicable Do
38、cuments The following publications form a part of this specification to the extent specified herein. Unless otherwise indicated, the latest issue of SAE publications shall apply. 2.1.1 SAE Publications Available from SAE International, 400 Commonwealth Drive, Warrendale, PA 15096-0001, Tel: 877-606-
39、7323 (inside USA and Canada) or 724-776-4970 (outside USA), www.sae.org. Kemmer, M.: “Airbag-Inflation Noise Evaluation and Analysis, presented to SAE Airbag System Task Force, May, 1997. Kemmer, M.: “Evaluation and Analysis of Airbag Inflation Noise“, presented to SAE Airbag Systems Task Force, Feb
40、ruary, 1998. Ochs, J.: “Airbag Inflation NoiseEvaluation and Analysis“, presented to SAE Airbag Systems Task Force, May 13, 1997. Price, G.R.: “Predicting and Ameliorating Hearing Hazard from the Noise of Airbag Deployment, presented to SAE Airbag Systems Task Force, 1997. Price, G.R. and Kalb, J.T.
41、: “Modeling Airbag Noise Hazard: An Engineering Approach“, presented to SAE Airbag Systems Task Force, October, 1998. Price, G.R. and Kalb, J.T.: “Airbag Noise, the ARL Ear Model and Progress Toward a Noise Standard; Comments on the Weissach Tests and the NATO RSG Meeting“, presented to SAE Airbag S
42、ystems Task Force, March, 1999. Rouhana, S.W., Webb, S.R., Wooley, R.G., McCleary, J.D., Wood, F.D., and Salva D.B.: “Investigation into the Noise Associated with Air Bag Deployment: Part IMeasurement Technique and Parameter Study“, in Proceedings of the 38thStapp Car Crash Conference, SAE Technical
43、 Paper Number 942218, 1994. Rouhana, S.W., Dunn, V.C., and Webb, S.R.: “Investigation into the Noise Associated with Airbag Deployment: Part II - Injury Risk Study Using a Mathematical Model of the Human Ear,“ in Proceedings of the 42ndStapp Car Crash Conference, SAE, 1998. Rouhana, S.W.: “Investiga
44、tion of Hearing Loss Associated with Airbag Deployment: Human Ear Model vs BBN Method“, presented to SAE Airbag Systems Task Force, January, 1998. Rouhana, S.W.: “Airbag Noise: Research, Description and Status“, presented to SAE Airbag Systems Task Force, May 13, 1997. Rouhana, S.W.: “Issues to be C
45、onsidered in Drafting a Standard Measurement Procedure for Assessing Airbag Noise“, presented to SAE Airbag Systems Task Force, May 13, 1997. SAE J247FEB87 SAE Recommended Practice-Instrumentation For Measuring Acoustic Impulses Within Vehicles Wunsch, Chris: “Airbag Inflation Noise Tests Conducted
46、at Porsches R see Threshold Shift below) SAE The International Engineering Society for Advancing Mobility Land Sea Air and Space SL Sensation Level (speech intensity) SAE INTERNATIONAL J2531 APR2016 Page 8 of 18 SPL Sound Pressure Level = 20 log (measured Pressure/reference Pressure) TC Technical Co
47、mmittee TTS temporary threshold shift in hearing (hearing loss that recovers; see Threshold Shift below) WG Working Group 3.2 Definitions 3.2.1 ACOUSTIC REFLEX Transmission of sounds through the middle ear can be attenuated by means of the middle ear muscles (Tensor Tympani and Stapedius Muscle). Th
48、ese muscles are triggered by the Trigeminal and Facial nerves. The Acoustic Reflex, can cause contraction of these muscles and can be elicited by loud sounds, vocalization, tactile stimulation of the head or general body movement (Pickles, 1988). This reflex is absent in 6.7% of “normal hearing“ adu
49、lts. 3.2.2 ACOUSTIC TRAUMA Hearing loss or other auditory disturbance associated with exposure to a loud noise or series of loud noises. 3.2.3 A-DURATION A measurement of the length of time of the low frequency component of an impulse noise pressure-time history. It is calculated from the first rise above the ambient pressure to the time the pressure first returns to zero. 3.2.4 ALPHA CABIN A reverberation chamber having li
