CONTRIBUTION TO DEF IN ING THE HUMAN TOLERANCE TO PERPENDI CULAR S IDE IMPACT *

A. Fayon , C . Tarri ere , G . Wal fi sch Laboratoi re de Phys i o l ogie et de Bi omecan ique de 1 ' Associ at i on Peugeot­Renaul t , La Garenne-Col ombes ( 92 ) , France .

· c . Got , A . Patel , Insti tut de Recherches Orthoped iques , Höpita l Raymond Poi ncare , Garches ( 9 ? ) , France .

The protecti on of the passengers of pri vate cars whi ch are struck s i de-on i s a maj or prob l em as yet unresol ved . Too l i tt l e data i s avai l ab l e on the human tol erance to s i de-on i mpacts . The behaviour of conventi onal impact test dummi es di ffers too much from the behaviour of the human . Lastly , pri vate cars do not possess anv ver i tab l e paddi ng , the effecti veness of whi ch cou l d be stu­d ied by means of mul ti -disci pl i nary s urveys of acc i dents .

The present study uses the res u l ts of the free fa l l of ei ghteen human s ubjects . These stri ke ri gid surfaces or s urfaces covered with shock-absorb i ng materi a l s si de-on at the thorax and pel vi s . These tests were reproduced wi th Hybrid I I dummi es . A contri buti on wi l l be made to knowledge of human to l erance to l ateral i mpacts , the des i rab l e characteri sti cs of a dummy for s i de-on i m­pact and for protecti on padd ings .

Th i s work fo l l ows from that a l ready pub l i shed ( 1 ) ( 2 ) concern i ng l atera l i mpact against the head and has been conducted wi th the s ame mental approach .

EXPERIMENTAL METHODS

The s ubject or dummy i s hung and then re l eased i n order to drop freely agai nst the s i de , in the pos i t i on shown in fi gure 1 . The s i de struck varies for reasons re l ated tö the experimental cond i t i ons .

Two confi gurati ons for the arms with rel at i on to the trunk were used .

In the fi rst pos i t i on , the arm on the s i de struck l i es at only a s l i ght ang l e to the thorax , in a pos it ion s imi l ar to that of a passenger in a car . Th i s res u l ts i n a fai rly rea l i stical i nterference between the arm and the thorax .

I n the second pos i t i on , the arm on the s i de struck i s at an ang l e of about 90° to the thorax and does not compress i t when the i mpact occurs .

(*) Th i s r�sear�h was performed with the col l aborati on of Anatomy Labo­ratory of th� B 1 omed 1 ca l Research and Teach ing Department ( U . E . R) of Rene Descartes Un1 vers i ty - Pari s - Pr Del mas .

� c.t..o I"'� i "'j 1-o �u'bi�c.. r

po fyvr�t-J, ,H, foci wt ,.,q,..J ! <A -v 1'5o _, ! L s o H : ol N 1 1 S'J f l

Fi gure 1 - typ i ca l dummy and s ubject pos i ti ons , before i mpact .

Depend ing on the part i cu l ar tes t , the fol l owi ng are the types of surface st ruck :

a ) a ri g i d p l ane con s i st i ng of metal p l ates of suffi ci ent d imen s i ons to extend beyond the compl ete trunk of the subj ect , i nc l udi ng the shou l der .

b ) The same p l an e , covered with a shock-absorb i ng materi a l 8 cm th i c k . Th i s mater ia l was a semi -ri g id polyurethan foam .

c ) A set of two ri g id but separate p l ane surfaces , one concern i ng the thorax and the other the pel vi s . Th i s comb i n at i on does not di rectly i nvo l ve the shou l der .

d) A set of two paral l el epi peds cons i st ing of other shock-absorb i ng materi a l s , one for the thorax and the other for the pel v i s . The den s i ty of these s hock-absorb ing e l ements was mod i fied i n the l i ght of the resu lts ob­tai ned i n the i n i ti a l tests : a modi fi cati on appears i n the tab l e of resu l ts .

I n th i s l ast confi gurat i on , the shoul der i s not s truck di rectly . (*)

The tab les of resu lts i ndi cate the experimental condi t i ons of each test and the hei ghts through wh i ch the subject or dummy fal l s . Al so refer to fi gu­res 2 and 3 .

The subjects cons i s t of fresh non-embal med cadavers or cadavers wh i ch have a l ready been subject to a head impact but without damage to the thorax , as reported i n ( 1 ) ( 2 ) . I n the l ater case , the head and neck were removed and the t i s s ues were treated to stab i l i se them . Th i s i s brought about by perfu­s i o n with a mi xture of water , fonnol and chi na i nk used to detect bra i n i nj u­ries duri ng head i mpact tests , but i n no case can the resul ts of th i s stabi ­l i sation of the ti ssues onto the s kel eton be as s i mi l ated to emba lmi ng .

Al l the s ubjects were equi pped with two tri axi a l accel erometers .

The fi rst accel erometer was screwed to the fourth dorsa l vertebra .

The second was a l s o screwed to the sacrum i n the med i an sagi ttal p l ane , 90 mm be l ow the i l i ac crests .

The acce l erometers and measuring sys tems meet the requi rements for mea­suri ng accel erati on of the fuorax of Safety Standard 208 ( SAE J 2 1 1 b and 180 Hz ) .

Deflect i on of the thorax was measured by us ing fi l ms taken duri ng these tests (w ith a Stal ex 1000 frames per second camera) .

Dur ing the tests made agai nst a ri g id surface , the rel ati ve movement of s i ghti ng marks on the thorax seen from the back was observed .

(�descri bed on fi gure 1

w

0 0 Fi

gure

3 -

thor

ax i

njur

ies

afte

r te

sts

Duri ng the tests agai n st a shock-absorb i ng materi a l , the penetrati on of the thorax i nto the materi a l makes i t i mpos s i b l e to observe the reference p l ane di rect l y . Th i s i s why a cy l i ndri cal rod was used i nserted cross -wi se through the thorax . One of i ts ends was attached to the contour of the thorax of the s i de struck , wh i l e the other carried s i ghti ng marks the movement of wh i ch , wi th re l at ion to the thorax , was observed . The defl ect i on con s i dered was that wh i ch occured i n the mean p l ane of the thorax between the thi rd and fourth r i b s .

A l oad measuri ng p l ate usi ng Ki s t l er cel l s was beneath the s urface struck by the thorax . The l oad measured approaches that app l i ed to the top of the trunk , i n v iew of the smal l mass of the shock-absorb ing materi a l . The frequen­cy FH i n th is measurement i s 600 Hz .

After the test , an autopsy was carri ed out on each s ubject .

Knowl edge ot the strength of the i r skel eton enab les the res u l ts to be i nterpreted more f ine ly . W i th th i s i n v iew , undamaged parts of the r i b s were samp l ed after the test and s ub jected to bendi ng and s hear mechani cal tests as descri bed i n ( 3 ) . L i kewi se , the ca lc i nati on of a fragment cf ri b made i t pos s i b l e to determine the percentaqe by wei ght of mi neral s a l ts i n the bone . The overal l resu l ts ( tab l e 1 ) s how that excepti onal s ubj ects the skel etal strength of whi ch i s too great or too smal l , wou l d b i as the resu l ts .

RESULTS AND D ISCUSSION

Inj uries - On the thorax , under the experi mental condi t ions brought about , a great many ri b fractures were observed . S ubject 88 a l so presented a b roken col l ar bone on the i mpact s i de ; th i s s ubject i s one of those wh i ch struck a s urface i nvol v inq the enti re shou l der . Fracture of the sternum was a l s o observed i n s ubj ect 1oe . Fi gure 3 shows the l ocat i on of the fractures revealed by the autopsy . Al l the impacts are s hown as occuri ng on the r igh t hand s i de of the thorax i n thi s fi gure ; certai n r i b cages were therefore shown schemati ca l ly wi th the l eft and ri ght hand s i des i nverted .

Fractures occur more frequent ly on the s i de struck than on the oppos i te s i de and more occured on the forward face of the thorax than the dorsal face .

The 11 fl ai l . ehest" l eve l of severity was often reached ; general ly , a l s o , fractures occured at two poi nts on a number o f the ri bs on the s i de struck , combi ned wi th fractures at one po int on ly on the ribs on the oppos i te s i de .

No i nj ury occured for a drop through 0 . 50 m onto a ri g i d surface , and unacceptab l e 1horax i nj uri es ( AI S = 4) occured twi ce out of four drops through 1 m .

For a drop of 2 m onto a shock-absorb i n g materi a l measuri ng 14 cm a l ong the s i de and with dynami c characteri sti cs very remote from the opti mum ones , the i nj uries were of severity i ndex A IS � 3 i n the three correspondi n9 sub­jects , one of them compl etely escap i ng i njury . These were the l eas t severe i nj ur ies obtai ned wi th a shock-absorb i ng materi a l .

At the pel v i s ( tab l e 2 ) , no i nj u ri es occured i n the maj ority of cases .

. .. . . I _> '

Subject No

104

105

109

1 1 1

118

1 1 9

92

100

101

88

95

96

102

107

108

120

121

122

A

B

Tab l e I - Res u l ts of rib test ing

Static bend i n g �ests

ene rgy f defl ection J max IT111

daN

C . 21 1 7 . 6 8

1 . 05 1 7 . 2 12

0 . 44 6 . 6 1 6'

1 . 49 1 6 . 8 1 6

1 . 0 1 6 . 5 8 . 5

0 . 55 1 2 8 . 5

1 . 80 22

0 . 7 1 1 0 . 4 1 2

0 . 23 25 . 1

0 . 9 1 3-1 . 8 4

0 . 2 5 6 . 4 5 . 7

0 . 74 1 3 . 3 14 . 5

0 . 96 1 7 . 9

1 . 4 26. 8

0 . 3 1 5 . 4 3

Stat i c sheari ng tests

2 W 2 F max J daN

2 . 8 101

1 . 7 46

0 . 8 31

2 . 0 64

2 . 9 74

0 . 9 39

2 . 1 122

2 86

1 . 2 55

4 . 6 1_20

1 . 4 7

2 .·2 59

2 . 2 66

3 . 2 84

4 . 9 163

Averages - from 2e previ ous ly tested ma l e s ubj ects

0 . 8 20 6 . 5 2 . 6 75

Averages - from 5 previous·ly tested fema l e subj ects

0 . 44 1 7 2 . 5 120

c41 mi nera 1

s a l ts

J.:-0

29

2 7 . 5

2 1 . 5

24

30

26

37

3 7 . 5 26

32

27 27

34

2 7 . 5 27

26 . 5

3 2 . 5

40 . 5

26 . 5

28

Tabl

e II

I -

Meas

urem

ents

con

cern

ing

thor

ax

Te

st

fa 1

1 0.

R (f

R G

ad

d

Fo

rc

e m

ax

. (d

ar!

) de

fle

ct

ion

No

he

igh

t

pe

ak

3rns

s. I.

m

ea

sure

d/

nor

ma

liz

ed

i AI

S a

rms

po

s it

i on

m

9

g -

--

co

nt

inu

ou

s r

ig

id s

ur

fac

e

104

1

. 6

2 5

5

187

59

0/

69

0

30

4 di

spla

ced

105

1.

56

50

189

7

00

/8

70

32

3 II

109

1

. 34

29

6

2

--

17

.5

4 n

orm

al

11

1

1.

48

4

4

126

46

0/

580

15

3 II

2 se

para

te r

igid

sur

face

s 1

18

0.5

34

29

4

5

250

/3

30

1

1

0

no

nna

l 1

19

0

.5

27

2

6

33

24

0/

360

2

0

0

II

--

cont

inuo

us p

ad

din

g -

e =

8 c

m

92

2

. 69

59

3

24

10

90

/

--

4 df

spla

ced

100

2

. 54

5

1 20

9

630

/7

70

-

4 no

nna 1

101

2.

42

38

1

31

8

00

/10

20

-

5 "

88

3

. 8

4 6

5

43

6

950

/

--

4 no

nnal

95

3.

83

74

410

12

40

/

--

4 di

spla

ced

96

3

. �

78

-

6{1.8

116

0/

--

4 II

--

2 se

para

te m

olde

d el

ement

s -

hard

10

2

3.

82

60

34

5

87

0/

110

0

-5

nonn

al

107

3.

75

70

39

2

64

0/

94

0

-4

II

108

3

. 7G

6

2

33

5

e4

0/

110

0

-5

II

2 se

pa

ra

te m

old

ed

ele

men

ts

-s

oft

120

2

. 4

0

32

100

t>

90

/93

0

35

3

no

rma

1 t \�

121

2.

42

3

7

114

10

20

/10

20

24

3

II

122

2.

44

40

147

56

0/

78

0

22

0

II r\

„..,

l,J-1

Th i s absence of i nj uri es occured every time for the less severe tests . 3 m drops res ul ted i n three fractures i n s i x s ubj ects .

The type of fracture wh i ch seems to appear the most often i s a fracture of the pubi a l i sch i o and i l i o branches on the s i de struck ( i nvo l vi ng l i tt le or no di s p l acement ) . The correspondi ng AIS l evel i s 2 0" 3 , depending on whe­ther d i s p l acement occurs or not .

Re l at i onsh i ps between thorax i nj uri es and the measurements of accel era­tion - The resu1ts of measurements of the accelerat1 on on cadavers are given Trltable 3 . The maxi mum acce l e rati ons measured at 04 l i e between 27 and 84 g . Cl i ppi ng of the peaks of the curves for an i nterval of 3 ms reduces thi s bra­cket to 26 to 74 g .

Part i al i nterference between the arm and the thorax p robably reduces the accel erat i on when th i s i nterference occurs .

The Unacceptab l e i nj ur i es obtai ned for the l owest accel erat ion ( 29 g du­ring 3 ms and an A I S of 4) appeared in s ubj ect 109 . Th i s 68 years o l d femal e s ubj ect s howed the l owest l e vel o f mi neral i sation i n a l l s ubjects , a s i s shown i n tab l e 1 g iv ing resu l ts of the ri b tests . The same tab l e a l so shows that th i s s ubj ect i s amongst the weakest ones , i n part i cu l ar d i s si pating the l east energy of al l the s ubjects during the s tati c shear test . l t can there­fore be e l i mi nated from the analysi s .

As i de from subject 109 , the l owes t l evel of acce l erati on accompani ed by an A IS va l ue of 4 i s 38 g ( s ubject number 10 1 ) . The corresponding s kel eton has mean strength wi th i n a reference s amp l e cons i sting of a l l the s ubjects undergo ing b i omechanical tes ts . Thei r strength i s wel l bel ow that of a popu l a­t i on of road acci dent vi cti ms .

The h i ghest accel erati on associ ated to an AIS of 3 i s 50 g for s ubj ect 105 , whi ch , l i ke s ubj ect 101 , i s a 11mean 11 subject .

The resu l ts as a who le of the measurements of accel eration di spl ay no d i s ti nct re l at i on between the maximum accel erat ion and the i nj uries ( fi gure 2 ) . One shou l d not forget that the tes ts were made at several i mpact speeds , res u l t i ng i n di fferent appl i cation t imes for the accel erati ons and the l oads . Th i s represents . an add i t i ona l factor unconducive to th i s re l at i o n . It wou l d therefore b e unfounded a t thi s j uncture t o s i tuate the tolerance o f the s ub­jects wi t h i n the 40-50 g , as one mi ght be tempted to do s o . A series of expe­r iments under i dent i ca l and real i sti ca l condi t ions i s necessary to determi ne whether the maxi mum accel eration may or may not act as an i ndi cator to the i mpact severi ty for the s ubject , thi s severity ori gi nati ng from phenomena other than the acce l erat i on , wh i ch i s only the materi a l mani festati on of thei r effects .

Corre l evance wi th the dumm ies - The tests made under i dent i ca l condi ti ons with a Hybrid II dummy revealed con s i derab l e di fferences i n the behavi our bet­ween the dummy and the human s ubjects .

In the event of i mp act aga i n st the shou l der , the l oads are transmi tted d i rectly to the sp ine of the dummy . Noth i ng s imul ated the re l ati vely fl exi b l e chain runn i n g from the h umerus to the sternum v i a the shoul der b l ade and the

108 � 6. :::J 1gz ü � 1� 86

.D 20 1Cf 6. 1rg ·c:

ö 1� 1 9& 1 5 1!0 z 1r; r:

9E V) 1 0 Q) •r-s... 2fR THORAX « . n :J .,.., 111

c:: 5 121 6. ( 3 ms ) •r- 6. . V) :J V) s... Q) 0 50 > V) � 1/) u � •108 Q) 3 .,.., � •102 .0 :J V) .D 20 1 0 7 e •101 c:: ·c 0 "ö V) 105

+-' 15 1 04 c:: z • Q) • •120 E Q) • s... 100 :J 10 V) '° F MAX ( d a N ) Q) E 1 1 1 Q) 5 • 121 Normaliz-ed

E • 0 V) 4- 1 1 119 0 0 500 1000 V) +-'

r- 1/) :J � .... V) :::J Q) ü 0:: �

.D 20 . 1 09 N ·c: • Q) 0 s... 105 :J 15 Ol z •

•r-1 0 4 . . 120

l.J....

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1 1 1 5 Ä 121 DEFLECTION '/,

• 118 1 19

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30�-·

\Y ,....}

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Te

st

fall

A

ge

Se

x ri

o

he

ig

ht

104

105

109

111

118

119 92

· 10

0 10

1 88

95

96

102

107

108 120

12

1 12

2

m 1.

1.

1 .

1 .

0.5

0.5

2 .

2.

2.

3 .

3.

3.

3.

3.

3.

2.

2.

2.

70

47

68

52

46

52

69

34

41

71

55

53

69

55

64

51

57

42

M M F t.4 �1 M F M M F M M M F H H M F

Tabl

e II

-An

thro

pome

trie

dat

a an

d re

sult

s co

ncer

ning

pel

vis

Imp

ac

t W

ei

Qh

t

Tho

rax

T

hor

ax

s i d

e Kg

br

ea

dth

c

ept

h QR

KR

R R R R· L. l l R R l l l R R R L L L

pe

ak

3ms

cm

cm

aq

ain

st

on

e

co

nt

inu

ou

s

riq

idlsu

rf

ace

59

54

49

53

27

. 27 27

28

20

20

21

21

ag

ain

st

two

se

par

at

e

rig

id

49

28

20

41

25

20

55

153 90

89

sur

fac

es

1 62

34

pa

dd

ing

-co

nt

inu

ou

s -

e

•

8 cm

56

52

25

28

26

20

28

30.

19

18

20 17

23

20

82

44

110 65

12

0 13

5

two

se

pa

ra

te

mo

lde

d e

lem

en

ts.-

har

d

53

42

50

27

26

27

21

17

19

62

77

74

two

se

par

ate

m

old

ed

ele

men

ts

-so

ft

70

75

45

30

32

?6

23

23

16

37

32

34

40

6€

70

47

33

30

50

38

77

60

.105 90

57

66

53

30

31 34

AIS

0 0 3 0 0 0 2 0 0 0 3 0 3 2 0 0 0 0

Pelv

is i

nj

ur

ies

f.

li

tt

le d

isp

lac

em

en

t,

R. i

schi

o an

d

ilio

­p

ubic

br

anc

he

s

f.

R+L

isc

hio

an

d

il

io-

pub

ic

br

an

ch

es

f.

li

tt

le d

is

pl

ac

eme

nt

L i

sc

hio

pu

bic

br

an

ch

f.

R 1

11

op

ub

ic

, f

. R

il

ia

c w

ing

, f

. +

d

is

pl

ac

eme

nt

R c

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f.

isc

hio

an

d

il

iop

ubi

c b

ran

ch

es

f

=

fr

ac

tur

e

co l l ar bone . The l oads recorded on the dynamometer p l ate at the top of the tho­rax are therefore much greater than those · reached under s imi l ar ci rcumstances on human s ubj ects ; as a resu l t , the accel erati ons d i s p l ay a h i gh peak of no s i gn i ficat i on .

I n the case of i mpact of the s i de of the thorax of the dummy aga i nst a s hock-absorb i ng materi al w i thout any i nterventi on of the s hou l der , on the other han d , a cons i derab l e reducti on in the accel erati ons of the thorax of the dummy compared to those of the human s ubj ects can be observed . Pos s i b l e expl anations may be the d i fferences i n we i ght those th i s wou l d appear to be i n adequate ( s ubj ect 1 2 1 wei ghs 75 kg) ; another expl anation may be the di fference i n equi ­va lent masses for the same we i gh t , s i nce a human , as opposed to the Hybri d I I dummy , does not con s i st of parts practi ca l ly sol i dly connected together , but of masses that are P ract i ca l ly uncoup l e d , s uch as the entrai l s compared to the s ke l eton . The mai n reason , however , res i des i n the d i fferences i n the dynami c ri gi di ty of the thorax of the Hybri d I I and the human s ubj ects and the ensuant rat i os between these ri g i di t ie s and those of the shock-absorb ing e l ements used .

To i l l ustrate thi s , s ubj ect 12 1 , whi ch we i ghs the same as that of Hybri d I I depresses the shock-absorbi nq e l ement agai nst the thorax by 65 mm , whereas the dummy presses i n a lmest compl etely a l ong one s i de and by 1 1 5 mm i n the mi ddl e . In contrast , the defl ect i on of the h a l f of the thorax struck of sub­j ect 12 1 located be l ow the acce l erometer , is 50 mm . The dummy d i sp l ays very l i tt le corresponding deflect i on . The path of the acce lerometer of the dummy i s greater , s i n ce thi s accel erometer l i es approximately on the s i de of the s hock­absorb i ng e l ement undergoi n g the most defl ect i o n .

l t can therefore be s a i d that the h uman s ubject and the Hybri d I I do not undergo comparab l e tests , wh i ch i s i n agreement w ith Me l vi n ( 4 ) .

------

fall impacted area i d . Thorax Pelv1s Observations

hei�ht cod. . 0. R O'R Gadd Force O R OR

m tests peak 3ms s . ! . datl peak 3ms

! . continuous ri- 104/105 5 1 4 7 193 1190 92 68 dulm\Y wi thout arm and "clav1cle" gid surface

109/111 106 54 248 2600 leo 100 comp lete

0 . 5 2 ri�id surfa- 118/119 17 l� 15 840 78 58 complete - no shoulder i mpact ces

3 . 8 cm paddin� 88 m 115 556 2400 116 93 complete

3 . 95/96 64 60 335 1000 60 5 5 w i thout arm and " c l a v i c l e "

2 . 9 2 55 52 220 860 52 51 comp l ete - broken "clavicle" during test

2. 2 molded ele- 120/121 27 26 80 1240 54 52. comp lete - no d i rect shoulder impact ments - soft 122

3 . 2 molded ele- 102/107 53 49 67 63 complete. But shoulder "bottomcd out" after ments - hard 108 impact

Tab l e I V - Resu l ts of measurements wi th durmni es

I nj uries and l oads appl ied to the thorax - A priori , the · di fferences i n the duration and method of appl1 cat 1 on of the l oads resu l ti ng from testi ng con­d it i ons render any general i sati on of the res u l ts i mpos s i b l e ( tab l e 3 ) . Further more , the i n d i v i dual vari ati ons of the wei ght of the s ubjects i ncrease the spread of the val ues of the l oads .

I n Order to reduce the effect of the di fferences i n wei ght i n the analy­s i s , we have app l ied the formu l a (-*) pub l i shed by Epp i nger ( 5 ) based on appl i ­cat i on o f dimens i onal analys i s ( 6 ) . T h i s formu l a was not estab l i shed w ith res­tri cted condi t i ons as to the method of appl i cat i on of the l oads on the s ubjects . We propose to ca l l i n what fol l ows the 11normal i zed force 11 , that res u l t i ng from appl i cati on of th i s formu l a i n order to fi ct i ti ous ly correct the wei ght of the wei ght of the s ubj ect to 75 kgfdummy wei ght)

We can then wri te that the s ubject wi thout a fracture havi ng s upported the h i ghest l oad on the thorax has i n fact s upported a normal i zed l oad of 780 daN ( s ubj ect 122 , a robust s ubject ) and that the severity of AIS 3 corres­pond i ng to the h i ghes t l oad i s that of s ubject 1 2 1 , a l so fai rly robust , on whi ch a force of 1020 daN ( true or normal i zed) was exerted .

Conversely , the severi ty of AIS 4 attai ned wi th the l owest l oad measured on the pl ate i s a normal i zed 690 daN .

These l oad fi gures are cl ose to the val ues actual ly app l i ed aga i nst the r i b cage a l one ; at the moment of maxi mum l oad , the arm i s i nserted i n front of the cage or has been stopped for some time .

I nj uri es and defl ect i on o f the thorax - The resu l ts are gi ven i n fi g . 2 The deflection cons 1dered is the relative defl ecti on , referred to the i n i ti a l wi dth of the thorax . Subject 109 i s d i fferent from the remai nder , and has a l ­been e l i mi nated fol l owing the observati ons concern i n g accel erati ons . T he as ­pect of the cl uster wou l d s uggest a corre l at i on between the i nj uri es and the defl ecti on , but s ubjects 1 1 8 , 1 19 and 122 l i e below the thresho l d of appearan­ce of fractures and shou l d be p l otted further to the right on the fi gure .

We shal l con fi ne oursel ves to stati ng that 30 % o f the re l ati ve defl ec­t i on of the thorax occurs i n conj unct i on wi th unacceptab l e i nj uries . These fi n d i ngs agree wi th those of Sta l naker ( 7 ) .

Use of the q uant i ty �r (wi dth/thi ckness of the thorax) defi ned as the 11morpho l ogy factor11 ( 7) di d not reduce the spread of the resu l ts .

I nj uries of the pe l vi s and meas urements of the accel eration - The s ub­jects d1 splayed no i nJ ury up to SOg /3ms , regardless of the test concerned . I f one cons i ders the group of s ubjects fa l l i ng onto paddi ngs from a hei ght o f 3m , i . e . at a vel oc ity of a l most 27 Km/h on impact , one fi nds a mcan max imum ac­ce l eration ' for 3ms of 72g , together with a mean AIS of 1 . 33 for s i x s ubjects . The Hybri d I I dummy gi ves 68 . 5g . S i nce the pe l v i s di storts only l i ttl e , the measurements of acce l erati on are much more coherent for the pel vi s , whether i n the cadavers or the dummies .

F Nor,.., , -

In view of the greater strength of the vi ctims i nvol ved i n acci dents ( compared to that of the cadavers ) , of the absence of i nj uri es of AIS.> 3 , and of l ow average AIS obtai ned , i t wou l d seem val i d to accept an accel erati on of 80g on the Hybri d dumll\Y as- protecti on l eve l criteri on .

However , thi s n umber can only be wi tho l d when associ ated wi th a paddi ng and an i mportant enough tlV .

For an i mpact associ ated to a l ower �'!, h uman tolerance i n g ' s i s pro­bably h i gher; wi thout paddi n g , the dumll\Y i ndi cates more g ' s than a h uman s ub ­j ect . We wou l d contemp l ate then hi gher val ues for a protection cri teri on . (*)

CONCLUS ION -

The devel opment of systems fi tted i ns i de the car for protect ing the tho­rax aga i nst l ateral i mpact and the eval uat ion of the i r effecti veness are not pos s i b l e wi th a dummy with characteri sti cs s imi l ar to those of the Hybri d I I . However , s uch dummies do enab l e the protection of the pel vi s to be roughly i n ­ves ti gated .

A dulllll\Y whi ch wou l d be appropri ate for the thorax shou l d compri se a l ess ri gi d l i nk between the sho u l de r and the ri b cage , whi ch shou l d a l so be made much more fl exi b l e . Protect i on cri teri a coul d then be adapted to s uch a dulffi\Y .

The m•:asurements made on human s ubjects woul d s uggest a maximum human tol erance to re l at i ve defl ect i on of the thorax s l i ghtly l ower than �O % and wou l d a l so s uooest that n. rl i s tri h ute� l oac' o� over 800 dar : shou l d not be ap­pl i e d . Th i s fi gure i s , however , only an order of magni tude wh i ch cou l d be used for temporari ly determi n i ng i nternal protecti on elements ; th i s fi gure cannot be used i n connect i on wi th an anth ropomorphic tes t dumll\Y .

Final l y , i t shou l d be pointed out that the present s tudy merely repre­sents the starti ng point for s ubsequent research .

RE FE REN CES ( 1 ) A. Fayon , C . Tarri ere , G . �/a l fi sch , C . Got , A. Patel - Performance of

he lmets and contri b uti on to the defi n i t i on of the tolerances of the human head to i mpact .

Meeti ng I RCOB I , Amsterdam , Sep t . 1976 I RCOB I Secretari ate , 109 Av . S . Al l ende - 69500 Bron - France

( 2 ) A. Fayon , C . Tarri ere , G . Wa l fi sch , C . Got , A . P-atel - Contri but i on to the defi n it i on of the tol erances of the human head to i mpact - Proceed i ng ' s of the 6th E . S . V . Conference i Wash ington , Oct . 1976

( 3 ) C. Got , G. Wa l fi sch , A. Fayon , G. Faverjon - Les caracteri sti q ues mor­pho l og iques , ch imiques et phys i q ues a�es cötes et l eurs rel at ions avec l a defl e­xion provoquee du thorax . - 2nd Int Conference I RCOB I - Avai l ab l e from I RCOB I Secretari ate .

( 4) J . W Mel vi n , D . H Robb ins , R . L Stal naker - Si de Impact response and i n­j ury - 6th ESV Conference , Washi ngton , Oct . 1976

( 5 ) R . H . Eppi nger D . O . T . NHTSA - Predi cti on of thoraci c Injury us ing mea­s urab l e experimental parameters

( 6 ) B . S Ho lmes , J . D . Col ton , - App l i cation of Scal e �odel i ng techn i q ues to crash worthiness , Saczal s ki etal , Eds . ( Uni vers i ty Press of Vi rgi ni a 1975)

( 7 ) RL Stal naker VL . Roberts , JM . Mc El haney- S ide Impact Tol erance to b l unt trauma SAE Paper 730979 - 17° Stapp conference

( 8 ) RL Sta l naker , JH Mc E l h aney , RG Snyder , VL Roberts - Door Crashwor­thi ness Cri ter ia SAE Paper 710864 - 15° Stapp Conference

(�) on dumll\Y - i f l ow �V or no paddi ng - n -.., 5 - � ..: