GHBMC Head Model Validation using head drop tests performed at Medical College of Wisconsin by Narayan Yoganandan and Frank A. Pintar in 2001

1. GHBMC Head Model Validation
using three Head Drop Tests performed by Narayan Yoganandan and Frank A. Pintar
Department of Neurosurgery, Medical College of Wisconsin, 2001
Made by:
Akshay Mistri

2. CONTEN
TS
• OBJECTIVE
• TEST DETAILS
– Test Setup
– Accelerometer Locations
– Specimen Details : Forehead
– Specimen Details : Right Lateral
– Specimen Details : Left Lateral
2
• MODEL SETUP
– Pad Properties
– Model Velocities
• RESULTS
– Forehead Impact
– CORA Rating (Forehead Impact : Left)
5
6
7
8
9
10
11
12
13
14
15
16

3. • RESULTS
– CORA Rating (Forehead Impact : Right)
– Right Lateral Impact
– CORA Rating (Right Lateral : Anterior)
– CORA Rating (Right Lateral : Posterior)
– Left Lateral Impact
– CORA Rating (Left Lateral : Anterior)
– CORA Rating (Left Lateral : Posterior)
– Vertical Force (Forehead Impact)
– CORA Rating (Forehead Vertical Force)
– Vertical Force (Right Lateral Impact)
3
CONTENT
S
17
18
19
20
21
22
23
24
25
26

4. • RESULTS
– CORA Rating (Right Lateral Vertical Force)
– Vertical Force (Left Lateral Impact)
– CORA Rating (Left Lateral Vertical Force)
4
CONTENTS
• CONCLUSION
• LIMITATION
• REFERENCES
• KEYWORDS
27
28
29
30
31
32
33

5. OBJECTI
VE
• To validate the GHMBC Head model using results of three
drop tests performed at Medical College of Wisconsin in the
year 2001:
– Forehead Impact [1]
– Right Lateral Impact [2]
– Left lateral Impact [3]
5
Test Ref: CHD1207
Test Ref: CHD1001
Test Ref: CHD1104

6. TEST
DETAILS
• Three drop tests were carried with varying heights of drop (0.6 – 3.05 m).
• Each drop test was performed only once using three different head
specimens.
• No fracture was observed in pre and post pathology tests in all specimens.
6
Drop Tests Drop Height (m) Head Weight (Kg) Velocity at Impact (m/s)
1. Forehead 3.05 3.32 7.74
2. Right Lateral 0.6096 2.35 3.46
3. Left Lateral 1.83 3.46 5.99

7. TEST
SETUP
• The test setup consisted of 2-inch thick pad of
durometer rating of 40, supported by a rigid plate
beneath it.
• Instrumentation consisted of a tri-axial load cell.
• Tri-axial accelerometers were used in the following
way:
– On the left and right of head in Forehead Impact test.
– On the anterior and the posterior ends in Right and Left
lateral impact tests.
7

8. ACCELEROMETER
LOCATIONS
8
Right Left Anterior Posterior
Forehead Impact Right & Left Lateral Impact

9. SPECIMEN DETAILS :
FOREHEAD
Description
9
Sex : Male
Age : 75 years
Weight : 73.1 Kg
Height : 1.7 m
Anthropometric Information
Weight : 3.32 Kg
Weight of Instrumentation: 0.09 Kg
Head Circumference : 533 mm
Head Height : 165 mm
Head Breadth : 152 mm
Head Length : 197 mm
Skin Thickness : 3 mm

10. 10
SPECIMEN DETAILS: RIGHT
LATERAL
Description Anthropometric Information
Sex : Female
Age : 87 years
Weight : 48 Kg
Height : 1.55 m
Weight : 2.35 Kg
Weight of Instrumentation: 0.09 Kg
Head Circumference : 540 mm
Head Height : 171 mm
Head Breadth : 149 mm
Head Length : 203 mm
Skin Thickness : 2 mm

11. 11
SPECIMEN DETAILS: LEFT
LATERAL
Description Anthropometric Information
Sex : Male
Age : 77 years
Weight : 71 Kg
Height : 1.78 m
Weight : 3.46 Kg
Weight of Instrumentation: 0.09 Kg
Head Circumference : 559 mm
Head Height : 171 mm
Head Breadth : 165 mm
Head Length : 190 mm
Skin Thickness : 4 mm

12. MODEL
SETUP
12
1
• Rigid plate beneath the impact pad was
constrained on the bottom
2
• Head model was scaled to match the mass of
the specimens in each test and then oriented
according to the respective tests.
3
• Models were simulated using impact velocities
of the specimens in the three tests.
4
Acceleration & Force time histories were
observed at locations similar to accelerometer
locations in specimen.

13. PAD PROPERTIES [4]
13
Dimensions
(𝑖𝑛𝑐ℎ3
)
Mass Density
( 𝐾𝑔
𝑚𝑚3)
Elastic
Modulus
(GPa)
Short-Time Shear
Modulus (GPa)
Long-Time Shear
Modulus (GPa)
Decay
Constant
Poisson’s
Ratio
Rubber
Pad
(Blue)
2 X 12 X 12 1.5 X 10−6 1.75 0.0013 0.001 0.5 -
Rigid
Plate
(Green)
1 X 12 X 12 7.85 X 10−6 210 - - - 0.3

14. MODEL VELOCITIES
14
Impact Scenario Head Weight (Kg) Velocity at Impact (m/sec)
1. Forehead 3.31 7.74
2. Right Lateral 2.33 3.46
3. Left Lateral 3.44 5.99

15. RESULTS : FOREHEAD IMPACT
15
0
50
100
150
200
0 1 2 3 4 5 6 7 8 9
Acceleration[G]
Time [ms]
Forehead Impact: Left Accelerometer Test Model
Left
accelerometer
-30
20
70
120
170
0 1 2 3 4 5 6 7 8 9
Acceleration[G]
Time [ms]
Forehead : Right Accelerometer Test Model
Right
accelerometer
Test 162 G’s @ 3.28 ms
Model 168 G’s @ 2.91 ms
Peak Values
Peak Values
Test 129.9 G’s @ 3.36 ms
Model 125.9 G’s @ 2.90 ms

16. CORA RATING : FOREHEAD IMPACT (LEFT)
16

17. 17
CORA RATING : FOREHEAD IMPACT (RIGHT)

18. RESULTS : RIGHT LATERAL IMPACT
18
-20
0
20
40
60
80
100
120
0 1 2 3 4 5 6 7 8 9 10 11 12
Acceleration[G]
Time [ms]
Right Lateral : Anterior Accelerometer Test Model
Anterior
accelerometer
-50
0
50
100
150
0 1 2 3 4 5 6 7 8 9 10 11 12
Acceleration[G]
Time [ms]
Right Lateral : Posterior Accelerometer Test Model
Posterior
accelerometer
Peak Values
Test 69.5 G’s @ 3.84 ms
Model 90.25 G’s @ 3.82 ms
Peak Values
Test 134.92 G’s @ 2.64 ms
Model 138.66 G’s @ 3.04 ms

19. 19
CORA RATING :RIGHT LATERAL IMPACT
(ANTERIOR)

20. 20
CORA RATING :RIGHT LATERAL IMPACT
(POSTERIOR)

21. RESULTS : LEFT LATERAL IMPACT
21
-20
30
80
130
180
230
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14
Acceleration[G]
Time [ms]
Left Lateral : Anterior Accelerometer Test Model
-50
0
50
100
150
200
250
300
0 2 4 6 8 10 12 14
Acceleration[G]
Time [ms]
Left Lateral Impact : Posterior Acclerometer Test Model
Anterior
accelerometer
Posterior
accelerometer
Peak Values
Test 242.8 G’s @ 3.52 ms
Model 170.24 G’s @ 3.39 ms
Peak Values
Test 242.8 G’s @ 2.56 ms
Model 261.69 G’s @ 3.47 ms

22. 22
CORA RATING :LEFT LATERAL IMPACT (ANTERIOR)

23. 23
CORA RATING :LEFT LATERAL IMPACT
(POSTERIOR)

24. VERTICAL FORCE : FOREHEAD IMPACT
24
-1000
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
0 2 4 6 8 10 12 14
Force[N]
Time [ms]
Vertical (Z-axis) Force : Forehead Model Test
Vertical Force
Peak Values
Test 9031 N @ 3.93 ms
Model 8546.64 N @ 3.92 ms

25. CORA RATING : VERTICAL FORCE (FOREHEAD)
25

26. 26
VERTICAL FORCE : RIGHT LATERAL IMPACT
-500
0
500
1000
1500
2000
2500
3000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Force[N]
Time [ms]
Vertical (Z-axis) Force : Right Lateral Impact Model Test
Vertical Force
Peak Values
Test 2655.87 N @ 3.49 ms
Model 2658.33 N @ 4.08 ms

27. CORA RATING : VERTICAL FORCE (RIGHT LATERAL)
27

28. 28
VERTICAL FORCE : LEFT LATERAL IMPACT
-1000
0
1000
2000
3000
4000
5000
6000
7000
8000
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
Force[N]
Time [ms]
Vertical (Z-axis) Force : Left Lateral Impact Model Test
Vertical Force
Peak Values
Test 7013.48 N @ 3.97 ms
Model 6926.84 N @ 3.44 ms

29. 29
CORA RATING : VERTICAL FORCE (LEFT LATERAL)

30. CONCLUSION
• Thus, GHMC head model is validated using drop tests at Medical College of
Wisconsin.
• Results show similar trend and peak values.
• This is also confirmed by CORA ratings provided.
30

31. LIMITATIONS
• Along with mass scaling, the head models could also be scaled to match
specimen geometries.
• Accuracy in locations of impact points.
• Accurate properties of impact pad needed, since durometer is not an
accurate measure for the properties.
31

32. REFERENCES
32
1. Narayan Yoganandan, Frank A. Pintar. “CHD1207 – Head Drop Tests – Forehead Impact”
Medical College of Wisconsin : Department of Neurosurgery (2001).
2. Narayan Yoganandan, Frank A. Pintar. “CHD1001 – Head Drop Tests – Right Lateral
Impact” Medical College of Wisconsin : Department of Neurosurgery (2001).
3. Narayan Yoganandan, Frank A. Pintar. “CHD1104 – Head Drop Tests – Left Lateral
Impact” Medical College of Wisconsin : Department of Neurosurgery (2001).
4. Material Properties for Rubber Resource:
http://www.azom.com/properties.aspx?ArticleID=920.

33. KEYWORDS
• GHBMC : Global Human Body Models Consortium
• CORA : COR-relation & Analysis
• MCW : Medical College of Wisconsin
33