TYPICAL INJURIES CAUSED BY AIR-BAG IN OUT-CF-POSITION SITUATIONS - AN EXPERIMENTAL STUDY - G Schroeder, J Edam Insu für Rechsmedzn Medznsche Hochschue Hannover ABSTRACT Curreny many cars are equpped wh an arbag on he drver's or n addon on he passenger's sde Recen repors based on accden nvesgaons n he USA and European Counres, emphaszed he safey poena of he arbag Bu on he oher hand, was found ha n some cases, njures or even faaes are repored, when he car occupan s n a so-caed ou-of-poson (OOP), ha means pars of he occupan's body are very cose o he expandng arbag To gan an nsgh no he njury mechansm, en expermens were carred ou wh Pos Morem Tes Objecs (PMTO) The effec of he nfang fu-sze arbag was nvesgaed n saonary ess, when he dsance o he human head or ehes was 0, 50 and 100 mm The njury rsk was deermned by monorng head and horacc spne acceeraon The njury paerns were nvesgaed by auopsy - he njury mechansms were expaned on he bass of hgh speed fm anayss The resus showed ha he regsered eve of he HIC and he horacc spne acceeraon sgnfcany exceeded he commony used oerance eves The expandng arbag generaed fracures o he rb cage and sernum Even njures of nerna organs such as he ver were deeced In cases where he expandng arbag conaced he head drecy, we observed njures of he faca regon, for exampe superfca skn njures, and a nasa bone fracure, as we as severe ndrec njures o he neck regon BASED ON SURVEYS CARRIED ou n he USA, 50 road raffc faaes - approx 60% beng chdren - have been arbued o he arbag snce 's nroducon Severa cases recorded ncorrec depoymen of arbags a exremey ow coson speeds Some of he faa njures o chdren were susaned, where a chd's car sea was fed facng he rear of he vehce or where he chd was no bucked up, as recommended Faa njures were caused by he depoymen of arbags, even n he even of a mnor accden, /RCOBI Conference - Hannover, Sepember 1997 409
where no faaes were o be ancpaed, when passengers' sea bes are fasened Afer cose examnaon, he accden sequence proved ha he carhoders were n very cose proxmy o arbag depoymen and were obvousy njured by he arbag modue sef The opma proecve funcon of he arbag for head and horax areas for he drver and passenger on coson s acheved when passengers are bucked up and seaed n a norma poson an mpac wh he compeey nfaed arbag In hs case he arbag s abe o opmze he mpac an he head and upper body In conras, passengers no seaed n a norma poson coud be njured on dfferen pars of he body, f hey are n very cose proxmy o he arbag durng nfaon We carred ou varous ess wh PMTO's n order o research ypca njury mechansms and rsks of njury for a vehce occupans, n cose proxmy o arbag depoymen RESEARCH DEVELOPMENT PROGRAM A car sea wh an adapabe seerng whee was mouned ono a sod mea frame o conform wh he seang capacy of a mdde sze auomobe The seerng whee was fed wh a sandard fu-sze (approx 65 Lre) arbagmodue (year of producon 1989) The sudy of sequences were acheved by means of 16 mm-hgh-speed cameras, hereby producng pcures wh 1000 exposures per second and addonay an overvew of 500 exposures per second To research he acceeraon affecs an PMTO's, acceeraon sensors were aached o dfferen pars of he body A raxa acceeraon sensor was aached o he regon of he cener of gravy of he head n fron of he cvus o monor he me-hsory of head acceeraon A furher raxa acceeraon sensor was frmy aached o he 6h horacc verebra The resus of he evauaons of he curves for head and ehes acceeraon were dagrammed The maxmum vaues, he 3-ms-vaues and he HIC were evauaed The auopsy of he PMTO was carred ou n he usua way, concenrang on he preparaon of he neck srucure The cervca vererbrae and a secon of he base of he sku were dsseced and frozen The deepfrozen specmens were nay dsseced by means of a band-saw, n he saga secon In hs way, dssecons were made beween he 3rd and he 4h cervca vererbra, and hen verca dssecons of he saga srucure of approx 35 degrees and 70 degrees were prepared o examne he gamen srucures beween he dens and he upper head condye 410 IRCOBI Conference - Hannover, Sepember 1997
EXPERIMENTS In order o smuae he Ou-Cf-Poson, we nfaed he arbag agans he head as we as he ehes, by means of adjusng he passenger sea and he seerng whee These fundamena posons are demonsraed n Fgure 1 and n Fgure 2 Fg 1 - Ches-poson Fg 2 - Head-poson In hese es seres, wo ras were carred ou n each case wh nfaon of he arbag agans he rbcage a dsances of 1 00 mm, 50 mm and 0 m m as we as on he regon of he head wh a dsance of 0 m m beween he md forehead and he arbag The PMTO were beween 20 and 75 years od, wo of hem femaes The body engh and wegh are comped n Tabe 1 Tabe 1 - Tesobjecs Run No agans 9 1 0ab 81 00a r 850a KOa : 9 I Küb -- head 1 head 50 ehes r mae 74 r r 178 1 11 r wegh [kg] 1a 20-50 45 74 1 femae 1 J mae oooooooooooooooooooooo : O j 0 oo 0 : 50 J 74 "''''''"""''"'"'"""'' 75 IRCOB Conference - Hannover, Sepember 1997 mae mae L j femae 1 '"''''''""''"''''''''''''''"" 168 72 1 70 1 75 -? 1 74 68 """"''"""'"''"'''''"""" 1 60 65 z ehes ; : BOa ehes 0a h r 11 00 ehes --- engh [cm] sex BSOb age [y] dsance [mm] 87 : 87 "'"'' ''''"'''"'""'"oooooooooooooooooooooo 73 41 1
RESULTS The daa for he 3ms-G's and he HIC of he resung head acceeraon as we as he 3ms-G's of he resung ehes acceeraon are comped n Tabe 2 In one case, he daa acquson sysem faed, so ha he resus for B 1 OOb are no avaabe Tabe 2 - Measuremen resus Run No 3ms-Head-G's HIC36 1 [ms] d [ms] 3ms-Ches G's B100a 35 112 69 329 33 01aabTTTr -r 1 n f ouooooooo u 1 + f o o OOOOooooooooo ooouooo oouo - :-:+ - -: + ooooo ooooooouou no u oe ouooo BOa 61 187 36 152 60 0abr9ar514r1ö:5r1:1T0a K:a r1aar13aar3:5r1:1r2a K"a;125248961 1 : : : 20 37 : 44 The njures whch were denfed afer he auopsy and afer nspecon of he cervca vererbrae, are comped n Tabe 3 DISCUSSION Based on he me hsory of he measures, he maxmum of each head and breas acceeraon was aready reached n a few m-seconds afer he depoymen of he arbag The evauaons of he hgh speed fms showed ha hese were obaned durng he na phase of arbag nfaon and, herefore, mmedaey afer he modue cover reeased he arbag Durng he ras wh depoymen of he arbag agans he orso secon, fexng movemens n he neck secon, due o he mass of nera of he sac head, were observed Fnay, upper body and head were ncreasngy acceeraed hrough he expandng arbag n he drecon of he backres The fu expanson of he arbag was reached, on he average, approx 30 mseconds aer Dependng on he sea poson, he acceeraed body made an mpac 70 o 125 m-seconds afer depoymen, agans he car sea back-res and head-res The speed of mpac was measured a 21 o 35 km/h accordng 412 IRCOBI Conference - Hannover, Sepember 1997
Tabe 3 - Deeced njures B100a : skn eson and aceraon of he skn n fron of he ehes ------------------------------------------------------ B100b : no deeced njures 850a : skn eson beow he chn and aceraon of he skn n fron of he ehes fracure of he sernum a he chondroserna juncon of he 4h rb fracure of he 3rd rb on he rgh, 9 cm besde he medan ne ------------------------------------------------------ 850b : skn eson above he fron of he ehes fracure of he sernum a he chondroserna juncon of he 2nd rb ear of he aneror and poseror gamen of he cervca spne beween verebra 5-6 ear of he Lg apcs dens a he appendx of he dens BOa : skn eson above he fron of he ehes and on he fron of boh upper arm regons ear of he aneror gamen of he cervca spne beween verebra 5-6 - --- ----------------------------------- - - -------- - ----- BOb : skn eson above boh cavcua regons and on he chn fracure of he Sernum a he chondroserna juncon of he 4h rb fracure of he 3rd rb on he rgh, 11 cm besde he medan ne KOa : skn eson and aceraon of he skn n fron of he forehead bruses of boh eyebas wh aceraons above boh roof of he orbs and of he upper eyeds open fracure of he nasa bone par ear of he aneror gamen of he cervca spne beween verebra 3-4 hemorrhage above he spna mennx n he cervca verebrae regon brusng of he sof ssues n-beween he processus spnosus n he regon of he cervca verebra 5-6 of he cervca spne ------------------------------------------------------ KOb : skn eson above boh eyebas sockes as we as above he brdge of he nose and he fron of he neck ear of he aneror gamen of he cervca spne beween verebra 6-7 ear of dsk beween cervca verebrae 4 un horacc verebrae 1 (degenerave pahoogca changes) brusng of he sof ssues n-beween he processus spnosus n he regon of he cervca verebra 2-3 un 5-6 fracure of boh upper bones of he arynx IRCOBI Conference - Hannover, Sepember 1997 413
o he fm anayss The body was hrown owards he back and was fed sghy upwards, dependng on he drecon of nfaon of he arbag and he sea poson of he PMTO Afer coson of he orso wh he car sea, he head was roaed far backwards over he head-res, causng exreme rerofecon Accordng o he knemacs, hree crca suaons for he body coud be observed Durng he nfaon phase of he arbags, wo njury mechansms are o be expeced, akng no accoun he monored acceeraon The frs of hese occurs hrough he drec force n he conac area beween he expandng pars of he arbag sysem sef and he human body The second occurs hrough ndrec njury mechansms as a consequence of bendng, ense and shearng forces beween pars of he body acceeraed a) drecy, by he arbag and pars of he body and b) ndrecy, ousde he area of he expandng arbag Furhermore, afer he expanson phase, njures can be expeced durng mpac of he body n he regon of he backres un Wh he ras a a dsance of 100 mm agans he fron rb cage, he resung acceeraon of he ehes was ower han 60 g Accordngy, ony one case of skn aceraon and skn eson above he fron of he ehes whou nner njures, was observed Wh hs conseaon, ony mpac ocazaon wh bone suppor, due o angena force o he skn, aceraon was observed; he pars of he body exposed o verca pressure componens, however, showed no obvous drec or ndrec njures Wh hese expermens, none of he pars of he openng arbag cover modue came no drec conac wh he body, so ha he susaned skn njures can ony be expaned as a resu of drec conac of he expandng arbag Our research was carred ou wh uncohed upper orsos for he purpose of anayss by knemacs, n respec o possbe njury mechansms Therefore, he observed skn aceraons and esons nfced on he uncohed orso woud no be expeced n case of fuy cohed persons In expermens wh dsances of 50 mm beween he arbag un and he body, we observed esons above he fron of he body due o smar njury mechansms The resus of he fm evauaon were ha, a hs dsance a he begnnng of he arbag depoymen, pars of he openng arbag modue made conac wh he fron rbcage In boh 50 mm ess rb cage fracures resued In boh cases fracures of he sernum a he chondroserna juncon of he 2nd or he 4h rb occurred; hese were bendng fracures resung from drec mpac force agans he fron rb cage In one expermen, we observed a furher soaed rb fracure pushed nwards hrough he same njury mechansm The evden njures of he neck/head regon can be ndcaed bes as a resu of ndrec forces due o rerofecon, causng bendng and shearng 414 IRCOBI Confercncc - Hannover, Sepember 1997
forces o he spna srucure, resung n earng of he aneror and poseror gamens of he cervca spne Comparabe njury paerns coud be observed wh ess where he orso was paced drecy on he arbag modue (dsance 0 mm) Here was aso evden ha - obvousy aso by rerofecon -- n one case, a ear of he aneror gamen of he cervca spne was deeced In he frs expermen open fracure of he nasa bone, as we as skn eson and aceraon of he skn n fron of he forehead, were caused by he mmedae depoymen of he arbag agans he head Afer anayss of he hgh-speed fms, hs coud be expaned by he drec conac wh he arbag modue cover For he second expermen, we removed he cover n order o soae he njures whch were caused by he cover sef In hs expermen we observed ony aceraon o he skn n areas wh a suppor of he faca bone srucure (roof of he orbs, brdge of he nose), whou fracures o he faca bone sef In boh cases, njures n he neck/head regon were susaned, whch can be arbued o he rerofecon mechansm, resung from he drec mpac force durng he arbag depoymen phase Through he njury mechansms, descrbed above, a njures observed on he neck/head regon and he surroundng ssue srucure can be expaned The frs expermen resued, apar from he gamen and dsk njures, n a hemorrhage above he spna mennx n he cervca verebrae regon In he second expermen, addonay, para nsaby of he cervca verebrae wh unceran brusng of he spna cord was deeced Aso, he evden fracure of boh upper bones of he arynx can be expaned hrough he exreme rerofecon of he head, whereby he back of he arynx makes drec conac wh he cervca spne Boh evauaed HIC-vaues of ess wh he arbag depoymen agans he head were consderaby above 1000; ha aready sgnfes a fe-hreaenng poena The rsk of njury o he bran, respecvey he bood vesses nsde of he sku, s ess objecve by auopsy, bu hese njures can be susaned by vng human bengs Ths s especay evden for rupures o he bood vesses n he sku as a consequence of roaon acceeraon of he head around he aano-occpa-jon, observed by fm anayss CONCLUSION Based on marke anayses, approx 500000 annua goba arbag depoymens are esmaed for he year 2000, as a resu of a gradua ncrease IRCOBI Conference - Hannover, Sepember 1997 415
n he quoa of vehces beng equpped wh arbags Apar from accdens wh absouey proven fe-savng funcons of he arbag for beed occupans, here w aso be cases where njures or faaes occur when occupans are subjeced o Ou-Of-Poson conseaons The nfaed arbag undoubedy proecs he head and orso of he passenger n he even of a head-on coson However, he expandng arbag maera poses a poena danger, no o be underesmaed, especay a he na expandng phase, f pars of he body are n very cose proxmy o he arbag modue s herefore our am o reduce he proven rsks of njures, caused by arbag sysems On he one hand, exreme OOP-suaons, eg dsances of ess han 100 mm o drec conac wh he modue surface, can be prevened by means of consrucve measures n he nner pars of he vehce On he oher hand, furher opmzaon of he sysems shoud be amed a, eg hrough he mprovemen of arbag maera of he modue cover, he depoymen echnque, as we as a sophscaed arbag sysem adapve o occupan parameers REFERENCES Berg, A, Frande, J, Schm, B u Maem, R: "Crash-Versuch m enem modernen Kompak-Fahrzeug m SRS-Arbag auf Fahrer- und Befahrer-See uner Berückschgung der Ou-Of-Poson-Probemak - Te 1" In: Verkehrsunfa u Fahrzeugechnk 1996 (34) Hef 1, S 7-14 Berg, A, Frande, J Schm, B u Maem, R: "Crash-Versuch m enem modernen Kompak-Fahrzeug m SRS-Arbag auf Fahrer- und Befahrer-See uner Berückschgung der Ou-Of-Poson-Probemak - Te 2" In: Verkehrsunfa u Fahrzeugechnk 1996 (34) Hef 2, S 45-52 Bg, D u Boso, AC: "Taorabe Resran Sysems: he Fuure n Frona Proecon" 3rd n Symposum on Sophscaed Car Occupan Safey Sysems, Karsruhe, Germany (1996) Ferguson, SA: "Updae on Arbag Performance n he Uned Saes: Benefs and Probems" 3rd n Symposum on Sophscaed Car Occupan Safey Sysems, Karsruhe, Germany (1996) Harsch, JD u Cuver, CC: "A Sudy of Drver neracons wh an nfang Ar Cushon" Proceedngs of 23rd Sapp Car Cash Conference, San Dego, Caoforna (1979), SAE Paper No 791 029 Hueke, DF: "An Overvew of Ar Bag Depoymens and Reaed njures Case Sudes and a Revew of he Leraure" SAE Paper No 950866, 1995 Hueke, DF, Moore, JL Campen, TW Samues, J u Levne, RS: "Upper Exremy njures Reaed o Arbag Depoymens" In: The Journa of Trauma 1995 (38) No 4, S 482-487 Langweder, K u Humme, T: "Arbags m reaen Unfageschehen - Anforderungen und Wrkmögchkeen" 3 n Akzo Nobe Symposum für Fahrzeugnsassen-Rückhaesyseme, Kön, Germany (1994) 416 TRCOBI Conference - Hannover, Sepember 1997
Löhe, Urch: "Arbag: Zu den Schuzwrkungen der Scherungssyseme Arbag und Scherhesgur und hre Grenzen Erkennnsse aus der Unfarekonsrukon" In: Verkehrsunfa u Fahrzeugechnk 1996 (34) Hef 6, S 171-173 Lund, AK u Ferguson, SA: "Drver Faes n 1985-1993 Cars wh Arbags" In: The Journa of Trauma 1995 (38) No 4, S 469-475 Maczyk, A u Adome, HD: "The Arbag Fodng Paern as a Means for njury Reducon of Ou-Cf-Poson Occupans" 39h Sapp Car Crash Conference Proceedngs, Warrendae, PA (1995), SAE Paper No 952704 Schmz, A: "Szposon - Enfuß auf den nsassenschuz" In: Verkehrsunfa u Fahrzeugechnk 1997 (35) Hef 2, S 47-53 Smock, WS u Nchos, GR: "Arbag Modue Cover njures" In: The Journa of Trauma 1995 (38) No 4, S 489-493 IRCOBI Conference - Hannover, Sepember 1997 417