VEHICLE COLLISION FORCE IN OFFSET BARRIER AND CAR TO CAR OFFSET TESTS

VEHICLE COLLISION FORCE IN OFFSET BARRIER AND CAR TO CAR OFFSET TESTS Hirotoshi lshikawa(1l, Kennerly H Digges(2l, Jason B Ennis(2l (1) Japan Automobile Researh Institute (2) National Crash Analysis Center, the George Washington University ABSTRACT This paper examines the loation, magnitude and diretion of rash fores ating on vehiles during frontal offset rashes Both artoar and ar to deformable barrier are examined A frame by frame analysis of rash test films permits the prinipal rash fore vetor to be positioned relative to the vehile's plane of deformation and enter of gravity Tests with left side overlaps onduted in North Ameria are analyzed The resulting analysis shows that the vehile rotates first lokwise and then ounterlokwise The hange in rotation is aused by a reversal in the diretion of the lateral rash fore The analysis shows subtle differenes in the transverse and rotational fores when omparing artoar and ar to deformable barrier offset tests These differenes may influene the fores on the lower leg and the rebound kinematis of the oupant CRASH TESTING IN THE FRONTAL OFFSET MODE has beome of inreasing interest in reent years Crash tests into an offset barrier with a deformable fae have served as a basis for onsumer information tests in Australia (Griffiths, 1994) and the United States (O'Neil, 1994) This form of testing is also being onsidered as a basis for a regulation in Europe and Australia (Lowne, 1994) The offset deformable barrier (ODB) test is intended to simulate a artoar frontal rash, with the ars offset Reently, the National Highway Traffi Safety Administration (NHTSA) in the United States onduted a series of artoar offset tests to examine the safety performanes in this rash mode (Hollowell, 1994) Six of these tests involved midsize ars equipped with air bags whih were rash tested using a 1991 Honda Aord as the rash partner The tests were at 112 km/h (7 mph) losing speed and a vehile overlap of 6 % The lnsurane Institute for Highway Safety (llhs) has tested fourteen 1995 model midsize ars into a deformable offset barrier and reported the results (llhs Status Report, 1995) The rash speed was 64 km/h and the overlap was 4 % llhs has also tested models of the Oldsmobile Siera in a large variety of rash modes These rash modes inlude offset artoar and ar to offset deformable barrier 189

In this study, the body of test data from llhs and NHTSA has been analyzed in order to ompare the fores imposed on vehiles du ring the various offset rash modes Vehile aeleration was determined from on board vehile aelerometers when available However, the instrumentation on the vehiles varies from test to test In order to develop omparative vehile aeleration data, film analyses of seleted rash tests were onduted The time history of the vehile enterofgravity position in the longitudinal and lateral diretion was determined and the resulting aeleration alulated The aeleration time histories for artoar and artodeformable barrier offset rashes are examined in the setions to follow CARTOCAR CRASH TESTS The NHTSA artoar offset rashes inluded six tests at 6 % left side overlap and 112 km/h losing veloity The six ars tested were The lsuzu Stylus, Chevrolet Corsia, Dodge Dynasty, Saab 9, Volvo 74, and Aord Station Wagon The rash partner for eah of these vehiles was the Honda Aord Sedan Table 1 shows the weights and speeds for eah vehile rash tested Film analysis of the motion of eah vehile was onduted, using about 5 ms time intervals From the analysis, longitudinal and lateral aelerations were determined for the vehile enter of gravity The longitudinal and lateral aelerations for the twelve vehiles in Table 1 are shown in Fig 1 The longitudinal (xaxis) aeleration trae has similar harateristis in all twelve ars The peak aeleration ranges from 25 to 3 m/s2 and it ours at 5 to 7 se The pulse duration is about 15 se The peak lateral (yaxis) aeleration ours at about the same time as the longitudinal aeleration, and ranges from 125 to 2 m/s2 During this time period the aeleration produes a fore to the right The lateral aeleration reverses diretion at around 75 se, and produes a fore to the left whih peaks at around 8 to 12 se The peak fore to the left (positive diretion of yaxis) is about 5 % of the fore to the right Table 1 NHTSA artoar offset rashes Test Overlap Vehile Mass Veloity No (%) m/s (km/h) 1544 6 Stylus 127 162 (583) Aord 1365 162 (583) 1666 6 Corsia 1283 162 (583) Aord 137 162 (583) 1678 6 Dynasty 1442 157 (565) Aord 137 157 (565) 174 6 Saab 9 1456 161 (58) Aord 137 161 (58) 1618 6 Volvo 74 1488 162 (583) Aord 137 162 (583) 1676 6 Aord STW 151 156 (562) Aord 137 156 (562) (kg) 19

15,,, 1 IOO t+tl l 5 l+++aflhl2!11i111 +h1"ßn lft!llj"'r'! f,pffffr'j+i > g 2 r fjrri!! 25 1 Pl# f +l 8 < 3 1+1ti " 15 35 1 15 2 5 f>,8l\'lil&,,1'1'jf'l,'l++\,+i+== g 1 t'1'1111"rtj e!! 15 1' ++l e < 2 1'"f'++l 5 25 ' 5 1 15 2 Fig 1 Longitudinal and lateral aelerations in NHTSA 6 % overlap arto ar tests at 1 1 2 km/h losing speed (7 models, 1 2 ars) so,r, 5 1t;tttt====;i 1 > 9 1 '"1++l "' ü 9438 15 2 9412A 94128 5 1 15 2 Fig 2 Longitudinal and lateral aelerations in llhs 5 % overlap artoar tests at 1 1 2 km/h and 1 28 km/h losing speed (Oldsmobile Ciera, 4 ars) The llhs artoar offset rashes inluded two tests at 5 % left side overlap and 1 1 2 km/h and 1 28 km/h losing veloities The two tests were both Oldsmobile Siera vs Oldsmobile Siera Table 2 shows the weights and speeds for eah vehile rash tested Longitudinal and lateral aelerations for the four vehiles in Table 2 are shown in Fig 2 Vehile aelerations from aelerometers were available in the llhs data However, some noise signals were found in the data, and so only the film data are used in Fig 2 The longitudinal (xaxis) and lateral (yaxis) aelerations of the l l HS data are similar to those of the NHTSA results However, the peak aelerations tend to be smaller and our later, ompared to the NHTSA 6 % overlap rashes The peak longitudinal aeleration ranges from 1 5 to 2 m/s2 and ours at 6 to 9 se The pulse duration is about 2 se The longitudinal peak aeleration is about 4 % lower and its time 2 se later than in the NHTSA 6 % overlap artoar tests The peak lateral aeleration ours at around 7 se This is about the same time as the peak for the longitudinal aeleration The lateral aeleration ranges from 1 to 1 5 m/s2, about the same peak values as the NHTSA test data The lateral aeleration reversal ours at around 9 se Table 2 llhs artoar offset rashes Test No 943 Overlap (%) 5 94 1 2 5 Vehile 1 988 Oldsmobile Ciera 1989 Oldsmobile Ciera 1986 Oldsmobile Ciera 1986 Oldsmobile Ciera 1 91 Mass (kg) 1 349 1 35 1 342 1 395 Veloity m/s (km/h) 1 7 8 (64) 1 7 8 (64) 1 5 6 (56) 1 5 6 (56)

5 1 15 2 Fig 3 Longitudinal and angular aelerations alulated from film data and from aelerometers (943A) The peak lateral aeleration to the left is about half the magnitude of the aeleration to the right The left aeleration peak ours at around 12 se As shown in Figs 1 and 2, the longitudinal and lateral aelerations in the llhs 5 % overlap artoar rashes are generally omparable to the NHTSA 6 % overlap rashes, although the test vehile and overlap ratios were different Linear and angular aelerations, veloities and displaements alulated from film data and from aelerometers (filter lass CFC 6 Hz) were ompared to validate the film analysis The auray of the film analysis in alulating linear and angular aelerations is onsidered to be aeptable, as shown in Fig 3 OFFSET DEFORMABLE BARRIER (ODB) TESTS The llhs has onduted an extensive series of ODB rashes in 4% left front overlap onfiguration Table 3 lists fifteen different ars tested at 64 km/h and three similar ars tested at 6 km/h Figure 4(1) shows the longitudinal and lateral aelerations for Oldsmobile Siera tested at 6 km/h and 64 km/h into a deformable offset barrier The longitudinal aeleration trae, taken from film analysis, has similar harateristis for all four ars The peak aeleration is about 2 m/s2 and ours at around 1 se The longitudinal peak aeleration is about the same in magnitude and about 5 se later ompared to the llhs artoar tests shown in Fig 2 The pulse duration is about 2 se, similar to the artoar tests The peak lateral aeleration ours at 6 to 9 se, about 1 to 4 se earlier than the peak longitudinal aeleration The ranges are from 5 to 1 m/s2, about 5 % lower than the llhs artoar tests During this period the aeleration produes a fore to the right The lateral aelerations reverse diretion at around 12 se and produe a fore to the left whih peaks at around 15 se The peak fore to the left (positive diretion of yaxis) is about 3 to 5 % of the fore to the right The reversal of the lateral aeleration is moderate in the Oldsmobile Siera ODB rashes at 6 km/h and 64 km/h Figure 4(2) shows the longitudinal and lateral aelerations for fourteen 1995 year models tested at 64 km/h into a deformable offset barrier Their average longitudinal and lateral aelerations are also indiated The aelerations of the 192

Table 3 llhs ODB (EEVC barrier) rashes Overlap Vehile Veloity Test Mass m/s No (%) (km/h) (kg) 4 167 (6) 1986 Oldsmobile Ciera 946 1 386 1986 Oldsmobile Ciera 4 1 67 (6) 948 * 1 1 49 4 1986 Oldsmobile Ciera 1 387 1 67 (6) 949 *2 4 Oldsmobile Ciera 1 79 (64) 9523 1428 4 954 1 995 Subaru Legay 1 38 1 79 (64) 4 1995 Volvo 85 1 79 (64) 955 1 565 956 1995 Mazda Millenia 4 1 79 (64) 1 593 4 957 1995 Toyota Camry 151 1 1 79 (64) 1 995 Mitsubishi Galant 4 1 79 (64) 1459 958 1 995 Honda Aord 4 959 1452 1 79 (64) 4 1 995 Ford Contour 143 1 1 79 (64) 95 1 4 95 1 1 1 995 Chevrolet Lumina 1 645 1 79 (64) 1 995 Nissan Maxima 4 95 1 2 1 57 1 79 (64) 4 1995 Ford Taurus 1 565 1 79 (64) 95 1 3 1 995 Chevrolet Cavalier 1 362 4 9514 1 79 (64) 4 1995 Chrysler Cirrus 1 553 95 1 5 1 79 (64) 4 1 995 Volkswagen Passat 1 557 95 1 6 1 79 (64) 95 1 7 1995 Saab 9 1489 1 79 (64) 4 * 1 Singlestage barrier *2 Twostage barrier so, ;;; so &'=t+"'1 so 1=;;;;;>"J,&+ 1 1'ii>'F'l)rfW""'l > " 2 1so 1+Wd#1*f"=;;;;;;rl 1 1+>;,<i1 946A 948A t; 15 2 +"'"'11 v 949A 949A 8 2 1+111 <C 2SO 952A <C 9S23A Lb = ==ij J t L J L = = ==i 3 L2SO L S 1 IS 2 5 1 15 2 "' ( 1 ) Oldsmobile C iera (3 ars at 6 km/h, 1 ar at 64 km/h) ISO IOO t++llrt 5 f [ 5 [ irtti<lttrt1 &;t,;, ), ISO > so t''im!! 2 *81TllfIL+J 1 1''l"Hll!l"l'i\'<ff++l!! 2SO Y+1 j1 ISO tt'lt11,++t <> "" 'L " n"""' l 2 i++t + li'h 3 1++f" Ml' "' 1 "' IPl'+l "' 5 3SO OOS 1 IS 2 '' 25 'O oos 1 15 (2) 1 995 year models ( 1 4 ars at 64 km/h) Fig 4 Longitudinal (x) and lateral (y) aelerations in l l H S ODB tests 1 93, 2

llhs ODB rashes at 64 km/h are similarto those at 6 km/h The peak longitudinal aeleration ranges from 2 to 35 m/s2 and ours at around 1 se The peak longitudinal aeleration is similar and 5 se later than in the NHTSA artoar tests The pulse duration is about 18 se, 3 se longer than in the NHTSA artoar tests The peak lateral aeleration ours at around 7 se, about 3 se earlier than the peak longitudinal aeleration, and ranges from 5 to 15 m/s2, about 5 % lower than the in NHTSA artoar tests FORCE ANALYSIS OF CARTOCAR TESTS Detailed fore analyses have been onduted for speifi artoar tests The tests seleted are the Oldsmobile Ciera to Oldsmobile Ciera offset rashes onduted by the llhs The losing speeds are 112 km/h and 128 km/h, and the overlap is 5 % Figure 5 shows the time history of the normal and tangential impat fores at the ontat surfae Impat fores were alulated by multiplying the CG aeleration by the vehile mass From the film analysis, ontat surfaes were determined and alulated to be inlined 4 degrees relative to the vehile front end during the ollision Tire fores were assumed to be negligible during the ollision The rash pulse in the normal diretion peaks at around 7 se with a value of 2 to 3 kn, and the duration is around 12 se The tangential rash pulse keeps lower than about 5 kn for the first 7 se and then maximizes at around 1 to 13 se with a value of about 15 kn The tangential rash pulse duration is around 2 se As shown in Fig 2, the longitudinal and lateral aelerations both peak at around 7 se and the peak lateral aeleration to the right is lose in magnitude and time phase to the peak longitudinal aeleration These phenomena an be explained by onsidering the time histories of the normal and tangential impat fores at the ontat surfae That is, the peak values of the longitudinal and lateral aelerations at around 7 se are aused mainly by the normal interation fore at the ontat surtae The lateral aeleration reversal and the seond peak at around 12 se are due to the tangential interation fore Figure 6 shows the angular aeleration and displaement in the 5 % overlap Oldsmobile Ciera to Oldsmobile Ciera offset rashes The first peak of the angular aeleration is about 5 rad/s2 (lokwise) ourring at around 6 se, approximately when the normal impat fore maximizes The seond peak of the angular aeleration is about 8 rad/s2 (ounterlokwise) at around 12 se, omparable to when the tangential impat fore maximizes As a result, the vehile rotates first lokwise and then ounterlokwise In order to gain insight into the rash fores on vehiles du ring offset tests, a fore vetor analysis was onduted from the film analysis A typial result is shown in Figs 7 and 8 Figure 7 shows the vehile ontat at 5 se The resultant rash fore vetor ats at the enter of the segment of damage Both vehiles are in ontat along the segment of damage At this time instant, the lateral fore ats to the right and the resultant fore vetor produes a lokwise 194

2SO 2SO 1+1++4l 943A g 2 11+,,i+H 9438 9412A u " ISO 1J'tt>"'fti 94128 S 1,44J!======! ;;; E 5;oJ, 5 z so oos 1 IS 94M 9438 9412A u 15 94128 l 1 z 2,,Lt4<T,,,=b,=t=t so '' 2 OOS 1 OIS 2 OIS 2 Fig5 Normal and tangential fores at the ontat surfae in 5 % overlap artoar test 1 8 ;,, 6 < 4, 2 u u "' 2 a ; 4 6 < 8 1 25 2 E o1s " u 5 ; 94128 1 "' < 15 1 943A 9438 9412A 94128 oos O S 2 OOS 1 Fig 6 Angular aeleration and displaement in 5 % overlap artoar test n CG n CG CG CG,, (h ooanjixlaxloaxo xxiapl eod'loijci y Fig7 Fore vetor at 5 seonds ( 1 se ) Fy Ft rjsj y Fig8 Fore vetor at 1 seonds rotation of the vehile Figure 8 shows the vehile ontat at 1 se At this time instant, the longitudinal fore is less than half its peak value and the lateral fore has reversed diretion The resultant fore vetor ats to rotate the vehile ounterlokwise The hange in rotation is aused by a reversal in the diretion of the lateral rash fore The vehile rotation in the NHTSA 6 % artoar rashes was similar to the llhs 5 % artoar rashes However, the lokwise rotation in the NHTSA data was signifiant when ompared to the llhs 5 % artoar rashes FORCE ANALYSI S OF ODB TESTS Crash tests of the Oldsmobile Ciera into a deformable barrier were seleted for detailed fore analysis The tests, onduted by llhs, were at 4 % overlap 1 95

into a deformable barrier at 6 km/h and 64 km/h Figure 9 shows the time histories of the normal and tangential impat fores at the ontat surfae Calulations on impat fore and ontat surfae were done using the film analysis as previously desribed The rash pulse in the normal diretion peaks at around 1 se, with a value of 2 to 3 kn, and the duration is around 2 se Comparing this result with the artoar tests indiates that the peak normal fore is similar and ours muh later (1 se vs 6 se) The tangential rash pulse keeps lower than 5 kn for the first 8 se and maximizes at around 1 4 se with a value of about 2 kn, whih is almost omparable to the artoar result Figure 1 shows the angular aeleration and displaement in the 4 % ODB test The first peak of the angular aeleration is about 3 rad/s2 (lokwise) ourring at around 7 se, about 3 se earlier than the peak time of the normal impat fore The seond peak of the angular aeleration is about 6 to 8 rad/s2 (ounterlokwise) at around 1 3 to 15 se, about the same time as the tangential impat fore maximizes The lokwise angular aeleration develops from 5 se and ontinues for about 3 to 5 se, with a peak value of about 3 rad/s2, whih about 5 % of the peak in the artoar rashes shown in Fig 6 The vehile lokwise rotation in the ODB tests is less than in the artoar tests COMPARISON O F CARTOCAR AND ODB CRASHES Figure 1 1 shows fore vetors in artoar and ODB tests from to 2 se, 25 z 25 1+++T 2 f +=r+rt,h if 15 r7t91t'e'\'tl 8 1 1,ql+ll+ z e 5 1,q>oJJ'f+>r= ; 5 1 15 948A "' 9523A 946A z 2 f! 8 1 ;; 5 u' 15 "' CO f 5 2 949A 5 1 15 2 Fig 9 Normal and tangential fores at the ontat surfae in 4 % overlap ODB test 5 2 15 1 946A /// v,,ij 948A 949A 9523A 5 / / /,,,, A 5 5 1 OIS Fig 1 Angular aeleration and displaement in 4 % overlap ODB test 1 96 2

in whih longitudinal and lateral fores are plotted sequentially at about 5 ms time intervals The fore vetor of the artoar test initially ats to propel the vehile 3 to 4 degrees to the right and rearward relative to the vehile enter line The fore maximum is at 64 se At this time, the lateral rash fore reverses its diretion and the longitudinal rash fore dereases, ausing the fore vetor to sweep to the left Du ring this period of 64 to 1 6 se, the magnitude of the rash fore vetor retains more than 5 % of its peak value After 1 6 se the vetor is inlined at approximately 45 degrees to the left rearward The fore vetor of the ODB test initially ats to the right and rearward relative to the vehile enter line lt maximizes at 1 4 se The peak fore vetor, with a similar magnitude, ours muh later ( 1 4 se vs 64 se) and inlines with a muh smaller angle ( 1 3 degrees vs 4 degrees) relative to the vehile enter line ompared to the artoar test After ontributing to a peak fore vetor at 1 4 se, the lateral rash fore reverses its diretion for a short time The fore vetors obtained from the artoar and ODB tests show subtle differenes in their diretion and time phase Figure 1 2 shows the lower tibia peak axial fore and its time in the NHTSA 6 % overlap artoar and llhs 1 995 4 % overlap 8 tests The peak axial fore of the lower tibia tends to be higher in the right leg than in the left leg, espeially in the artoar rashes Additionally, the peak axial fore of the right lower tibia is higher in the NHTSA artoar tests than in the llhs ODB tests The time of the peak axial fore both in the right and left lower tibias is around 5 se in the NHTSA artoar tests, whereas in the llhs ODB tests it is around 8 se in many ases lt should be noted that, in ase of the NHTSA artoar tests, the peak time of the axial fore almost oinides with the peak time of the vehile longitudinal and lateral aelerations However, in the ODB tests the lower tibia Cd l 5 1 ; 1 5 j ; 5 T 1 39 ms ; i ; ; ;, ; 1 6ms 1 1 5 2 25 3 35 Longitudinal fore (kn) t> Rear 5 1 1 5 2 25 3 35 Longitudinal fore (kn) t> Rear (2) ODB test (946A) ( 1 ) Cartoar test (943A) Fig 1 1 Comparison of fore vetors between artoar and ODB tests 1 97

O 1 1,, 1 1 2 t;; >( 'lro e b 4 Lefl lower 1ibia, ar1ar Right Jower tibia ODB s 1''41F n '9==='1 o 1 OiP D o a dll a a9 =lllltl 8 o O ' ' ' ' 5 15 1 E 3 E Cl) a Lefl lower 1ibia, ODB!! 5 2 Cl) 1 t)i) e Fig 1 2 Peak axial fore and its time of lower tibia in the NHTSA 6 % overlap artoar and llhs 4 % overlap ODB tests e 6 /\ ' 1 1 E g 2 bj) 3 5 os V 2 Lateralmedial (LM) Mx AnteriorPos1erior (AP) My,,p e 4 Peak axial fore (kn) l 6 Fig 1 3 Relationship between peak axial fore and LM and AP bending moments of right lower tibia in 4 % overlap ODB tests 2 Lower 1ibia LM bending moment, Cil Tibia axial fore r 'l 1 1 5 Righ1 lowr tibia ar1ar 1 (Mx) Lower libia AP bending momen1 (My) 15 2 6 5 1 15 2 Time(se) Fig 1 4 Axial fore and LM and AP bending moments of right lower tibia in 4 % overlap ODB test Fig 1 5 Typial lateral aelerations in rear seat, CG and foot area in 6 % overlap artoar test axial fore maximizes at around 8 se, near the peak time of the vehile lateral aeleration, and 2 se earlier than the peak time of the vehile longitudinal aeleration Figure 1 3 shows the relationship between the peak axial fore and peak lateralmedial (LM) and anteriorposterior (AP) bending moments of the right lower tibia in the l l H S 1 995 4 % overlap ODB tests There seems to be no orrelation between the peak axial fore and the peak LM and AP bending moments at the right lower tibia Figure 14 shows the time histories of the axial fore and lateralmedial (LM) and anteriorposterior (AP) bending moments of the right lower tibia in a llhs 1 995 ODB test In almost all ases, the lower tibia axial fore and LM and AP bending moments maximized simultaneously The only exeptions in the 1 4 tests were 2 ases with the right leg and 5 ases with the left leg In 5 ases of the 7 exeptions, the peak times of the axial fore were around 5 se, 3 se earlier ompared to the typial ases lt should be noted that these peak times tend to oinide with the peak time of the vehile lateral aeleration, rather than the peak time of the longitudinal aeleration Figure 1 5 shows the time histories of the lateral aelerations in the rear seat, CG and foot area in a NHTSA 6 % overlap artoar test Vehile aelerations in different loations are alulated by ompensating the angular 1 98

2 r,, 2 Tibia axial fore Foo1 area yaxis a 3 L j J===== ==1 3 5 1 15 2 (1) Cartoar (NHTSA) 3 6 5 1 15 2 (2) ODB (llhs) Fig 16 Vehile longitudinal and lateral aelerations and tibia axial fore in NHTSA 6 % overlap artoar and llhs 4 % overlap ODB tests aeleration and the positions The lateral whiplash aelerations are observed both in artoar and ODB tests, but are less signifiant in the ODB tests Note that the lateral whiplash aeleration is more signifiant in front seat foot area than in rear seat area where the vehile rash test aelerometers are loated Figure 16 shows the typial time histories of the vehile longitudinal and lateral aelerations and the right lower tibia axial fore in the NHTSA artoar and llhs ODB tests In the NHTSA 6 % overlap artoar rash, the lower tibia axial fore maximizes at around 5 se and then retains 5 % of its peak value for about 3 se The longitudinal and lateral aelerations in the foot area also maximize at around 5 se During the period of 5 to 8 se, the foot area longitudinal aeleration remains at a high level and the foot area lateral aeleration develops two peaks in opposite diretions In the llhs 1995 4 % overlap ODB tests, the lower tibia axial fore and the vehile lateral aeleration maximize at around 7 se simultaneously, then the vehile near CG longitudinal aeleration peaks at around 9 se Comparing this result to the artoar rash indiates that the lateral inertia fore ativated at the footankle region is less signifiant in the ODB tests ompared to the artoar rashes DISCUSSION Examination of the lower tibia axial fore data from the artoar tests indiates that the peak fore oinides in time with the peak lateral and longitudinal vehile aelerations During the 3 se period of high axial tibia loading, the lateral aeleration reverses diretion, ausing whiplash like fores The ODB test data indiates that the timing of the tibia loading period is different from the artoar tests The opportunity for ankle whiplash loading may be redued by the shorter loading period, the later onset of loading, and the redued lateral aeleration exhibited in the ODB tests A reent report on lower limb injuries in frontal ollision indiates that 3 % of the injuries ourred in the absene of intrusion (Thomas, 1995) Earlier researh 199

in the United States found that a high fration of ankle injuries were indued by inversion or eversion of the foot (Lestina, 1992) In most ases, the ankle bents laterally rather than in the diretion expeted under pure longitudinal loading through the brake pedal or toepan These results suggest that multidiretional inertia fores, inluding the lateral whiplash aeleration observed in artoar offset rashes, may influene the mehanism of lower limb injuries The lateral aeleration in artoar offset rashes is signifiant and reverses the diretion in short time However, this phenomenon is less pronouned in 8 tests An examination of dummy kinematis during the initial 15 se of the rash suggests that lateral aeleration has little influene on the observed dummy motion However, it is possible that it ould influene the footankle region whih is in diret ontat with the deelerating struture In addition, the oupant rebound kinematis ould be influened Further examination of this phenomenon by finite element modeling is now underway ACKNOWLEDGMENTS The authors would like to thank the lnsurane Institute for Highway Safety (llhs) for giving us the opportunity to use the test data from artoar rashes and ar to deformable barrier tests onduted by the llhs REFERENCE8 Griffiths M, et al, Australia's New Car Assessment Program, Paper No 9488 14, 14th ESV Conferene, Munih, Germany, 1994 Hollowell W T, Hithok R J, lmproved Frontal Impat Crash Test Data, Paper No 94889, 14th ESV Conferene, Munih, Germany, 1994 Lestina D C, Kuhlmann T, Keats T, and Alley R, Mehanisms of Frature in Ankle and Foot lnjuries to Drivers in Motor Vehile Crashes, 36th Stapp Car Crash Conferene, SAE paper 922521, 1992 Lowne R W, EEVC Working Group 11, Report on the Development of a Front Impat Test Proedure, Paper No 94885, 14th ESV Conferene, Munih, Germany, 1994 O'Neill 8, Lund A K, Zuby D S, Preuss C A, Offset Frontal Impats A Comparison of RealWorld Crashes with Laboratory Tests, Paper No 9484 19, 14th ESV Conferene, Munih, Germany, 1994 Status Report of lnsurane Institute for Highway Safety Crash Worthiness Evaluations, lnsurane Institute for Highway Safety, 1995 Thomas P, Charles J, Fay P, Lower Limb lnjuries The Effet of Intrusion, Crash Severity and the Pedals on lnjury Risk and lnjury Type in Frontal Collisions, 39th Stapp Car Crash Conferene, SAE paper 952728, 1995 2