PMHS Shoulder Stiffness Determined by Lateral and Oblique...

PMHS Shoulder Stiffness Determined by Lateral and Oblique Impacts

S. Caupp1, Y. Kang PhD1, K. Moorhouse PhD2, B. Suntay3, R. Herriott3, J. Bolte IV PhD1

1The Ohio State University, 2National Highway Traffic Safety Administration, Vehicle Research Test Center, 3Transportation Research Center Inc.

o  While side impacts are second in frequency for total motor vehicle crashes, side impacts have a higher mortality rate than other crash types1,2

o  In the study of the side impact, it is important to consider both lateral and oblique loading conditions; the oblique vector may result in more injuries1

o  The shoulder girdle is an important factor in determining the response of other parts of the body to lateral and oblique loading conditions2

o  Past research has shown that the scapula may be responsible for absorbing impact energy2

o  Study objectives include 1) comparing PMHS & adult volunteer quasi-static

(QS) data, 2) comparing PMHS quasi-static & dynamic data, and 3) comparing PMHS lateral & oblique dynamic data

o  In the future, these datasets will aid in developing a more biofidelic

shoulder model for both adult and pediatric ATDs

1.  Pintar, F., Maiman, D., Yoganandan, N. (2007). Occupant dynamics and injuries in narrow-object side impact. Enhanced Safety of Vehicles. Lyons, France.

2.  Subit, D., Duprey, S., Lau, S., Guillemot, H., Lessley, D., Kent, R. (2010). Response of the human torso to lateral and oblique constant-velocity impacts. Annals of Advances in Automotive Medicine, 54: 27-40.

3.  Suntay, B., Moorhouse, K., Bolte IV, J. (2011). Characterization of the pediatric shoulder’s resistance to lateral loading conditions. Enhanced Safety of Vehicles. Washington, D.C.

4.  Bolte IV, J., Hines, M., Herriott, R., McFadden, J., Donnelly, B. (2003). Shoulder impact response and injury due to lateral and oblique loading. Stapp Car Crash Journal, 47: 35-53.

ACKNOWLEDGEMENTS

Quasi-static testing

Modeled after a previous QS adult volunteer study3

REFERENCES

John Borstad, PhD, OSU The students and staff of the IBRC

Dynamic – Lateral Loading Condition

Dynamic – Oblique Loading Condition QS – Oblique Loading Condition

Dynamic – Lateral vs. Oblique Impacts

o  This study is ongoing; one more PMHS will be tested and dynamic data will be normalized to the 50th percentile male

o  Limitations: small sample size (QS: n = 2; dynamic: n = 4), QS DAQ metal sensitivity, inaccurate method of measuring the QS lateral vector, non-normalized dynamic data

o  QS data indicates a similar response of the PMHS and adult volunteer shoulder in the oblique loading condition (as compared to the volunteer’s relaxed muscle state)

o  The oblique vector in both QS and dynamic testing exhibited a lower force, higher displacement, and lower stiffness in the X-component compared to the Y-component

o  At at an impact speed of 4.5 m/s, it is difficult to make a correlation between the lateral and oblique impact vector according to injury patterns

SPONSOR

METHODS

CONCLUSIONS

INTRODUCTION RESULTS & DISCUSSION

Dynamic testing

Modeled after a previous dynamic PMHS study4

Test K (N/mm) 1301 132.0 1302 97.5 1401 90.5 1402 219.0

Average 135 ± 59

Test KX (N/mm) KY (N/mm) 1401 2.1 9.5 1402 1.0 11.2

Average 1.5 ± 0.8 10.3 ± 1.2 Previous Study3 1.6 7.0

•  Current FD curves fit the target corridors from the

previous study4

Dynamic – Oblique Loading Condition (continued)

Figure 3: QS oblique (X- and Y-components) full girdle FD curves for Test 1401, 4 trials

Table 1: QS Oblique Full Girdle Stiffness (K) Values

Table 2: Dynamic Lateral Full Girdle Stiffness Values

Figure 4: Dynamic lateral full girdle force-displacement curves

Figure 6: Dynamic oblique full girdle displacement (X- and Y-components) vs. time curves

Figure 5: Dynamic oblique force (X- and Y-components) vs. time curves

Impact Shoulder Joints Bones Test Lateral Oblique SC AC Ribs Scapula

1301 R. L. L./R. laxity -NA- -NA- -NA-

1302 L. R. L. laxity L. laxity L6/R7 fx L. coracoid

fx

1401 R. L. L./R. laxity -NA- R2/R3

fx -NA-

1402 L. R. L. laxity -NA- -NA- -NA-

Table 3: Injuries from Dynamic Testing

*R. = right; L. = left

−5 0 5 10 15 20 25 30 35 40 45−500

0

500

1000

1500

2000

2500

3000

3500Dynamic Lateral: Full Girdle FD [Y Component]

Displacement [mm]

For

ce [N

]

1301130214011402

Figure 1: Quasi-static test set-up Figure 2: Dynamic test set-up

0 10 20 30 40 50 60 70 80 90 1000

200

400

600

800

1000

1200

1400

1600

1800

2000Dynamic Oblique: Force [Y Component]

Time [ms]

Forc

e [N

]

1301OSH45L011302OSH45R011401OSH45L021402OSH45R02

0 10 20 30 40 50 60 70 80 90 1000

200

400

600

800

1000

1200

1400

1600

1800

2000Dynamic Oblique: Force [X Component]

Time [ms]

Forc

e [N

]

1301OSH45L011302OSH45R011401OSH45L021402OSH45R02

0 10 20 30 40 50 60 70 80 90 1000

50

100

150

200

Dynamic Oblique: Full Girdle Displacement [X Component]

Time [ms]

Dis

plac

emen

t [m

m]

1301OSH45L011302OSH45R011401OSH45L021402OSH45R02

0 10 20 30 40 50 60 70 80 90 1000

50

100

150

200

Dynamic Oblique: Full Girdle Displacement [Y Component]

Time [ms]

Dis

plac

emen

t [m

m]

1301OSH45L011302OSH45R011401OSH45L021402OSH45R02

53%

A) %B)

C) %D) %

Figure%18:%QuasiRstatic%oblique%force%vs.%displacement%curves%for%A)%subject%1401%in%

the%XRcomponent%forceRdisplacement%vector,%B)%subject%1401%in%the%YRcomponent%

forceRdisplacement%vector,%C)%subject%1402%in%the%XRcomponent%forceRdisplacement%

vector,%D)%subject%1402%in%the%YRcomponent%forceRdisplacement%vector%

%%

%

All%stiffness%values%are%reported%with%respect%to%the%full%girdle%deflection%

(measure%of%the%displacement%between%the%right%and%left%acromion)%in%the%XR%and%YR

components%based%off%the%FD%curves%for%each%test.%These%values%are%reported%in%

Table%3.%

0 5 10 15 20 25 30 350

50

100

1501401QS: Full Girdle FD Plot [X Component]

Displacement [mm]

Forc

e [N

]

Trial 2Trial 3Trial 4Trial 5

53%

A) %B)

C) %D) %

Figure%18:%QuasiRstatic%oblique%force%vs.%displacement%curves%for%A)%subject%1401%in%

the%XRcomponent%forceRdisplacement%vector,%B)%subject%1401%in%the%YRcomponent%

forceRdisplacement%vector,%C)%subject%1402%in%the%XRcomponent%forceRdisplacement%

vector,%D)%subject%1402%in%the%YRcomponent%forceRdisplacement%vector%

%%

%

All%stiffness%values%are%reported%with%respect%to%the%full%girdle%deflection%

(measure%of%the%displacement%between%the%right%and%left%acromion)%in%the%XR%and%YR

components%based%off%the%FD%curves%for%each%test.%These%values%are%reported%in%

Table%3.%

0 5 10 15 20 25 30 350

50

100

1501401QS: Full Girdle FD Plot [Y Component]

Displacement [mm]

Forc

e [N

]

Trial 2Trial 3Trial 4Trial 5

•  KY > KX due to the anatomical structure of the

clavicle and the scapulothoracic joint