Spine Fractures in Open Cockpit
Open Wheel Race Car Drivers
Reducing the Risk through Seat Modification
Terry R Trammell MD
OrthoIndy
Trammell Motorsports and Consulting
Indy Racing League
Henry Bock MD
Indy Racing League
trt@motorsportsmd.com
Introduction
• 11,000 cases of Spinal Cord Injury / year
in US
– 47.5% from MVA
• Spinal Cord Injury: Facts and Figures at a Glance.
2004, National Spinal Cord A Injury Statistical
Center.
• CIRENS Data
– Spinal Fractures 18.6% of Injuries in MVA
• Spine and Spinal Cord Injury in MVC: Smith and
Siegel New Jersey Medical School CIREN Center
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Introduction
• Incidence of Spinal Fractures in Indy Car
– From 1984 – 1996
• 8.5% of drivers injured
• 9.8% of all injuries (12/123)
– Spinal Injuries in Indy Car – a 12 year experience
Presented at the ICMS Mtg Toronto CA 11/23/06
– IRL 1996 – 2005
• 21.1% of drivers injured
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Introduction
PURPOSE OF INVESTIGATION
• Spinal Fractures
–
–
–
–
• Determine Kinematics
Occurrence
Location / level
Type
Severity
–
–
–
–
• Correlate with
direction of major
impact
Accident analysis
Barrier Impact test
Sled tests
Computer modeling
• Determine Load Path
• Preventative
measures
trt@motorsportsmd.com
Material and Methods
Spinal fractures occurring in Open cockpit
Open wheel single occupant racecars
1996-2005 Seasons
IRL,IPS,CART, F-1,Toyota Atlantic, and
Champ Car
trt@motorsportsmd.com
Materials and Methods
• Data Extracted
– Impact direction
– Fracture location
– Fracture type and severity
• Data Generated
–
–
–
–
–
Impact Barrier test
HYGE sled tests
X-ray Analysis of Spinal Contour
Measurement of Seated Position in race car
Computer modeling
trt@motorsportsmd.com
Material and Methods
• Driver Data
– Principal Author
• Initial or Final Treating Physician
• 35 of 36 surviving drivers
– Extracted from Medical Records
• Diagnostic Imaging (X-rays, CT and MRI)
• Autopsy Results in two
trt@motorsportsmd.com
Materials and Methods
SPINAL REGIONS
Occipital – Cervical (O-C1-2)
Cervical (C3 – T1)
Thoracic (T2 – T9)
Thoracolumbar (T10 – L2)
LumboSacral (L3 – Sacrum)
Courtesy DaVinci
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Materials and Methods
• Impact Vector Analysis in 35 of 38
– ADR – 2 data
– Accident reports
– Video tape
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Materials and Methods
• ADR – 2 Crash Recorder
– Attached to the chassis of
race car
– 6 axis accelerometer
– Senses and records 1000
times/sec
• Prior to, during and after a
triggering event
– Records
• X,Y,Z accelerations
• Yaw rate
• Steering angle
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Materials and Methods
Fracture Classification:
Comprehensive Classification System
Gertzbein in Controversies in Spine Surgery
Vol 1, 1999
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Materials and Methods
• Fracture classification
– Gertzbein’s Comprehensive Classification system
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Materials and Methods
Definition of Fracture Severity:
1. Compression Fracture without Deformity
(vertebral contusion)
2. Compression Fracture
<10% compression (single endplate)
<15° angulation
3. Compression Fractures
>10%<30% compression
>15° <30° angulation
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Materials and Methods
Definition of Fracture Severity:
4. Compression or single endplate burst fx
>30% compression
≥30° angulation
5. #4 + posterior column injury
Burst Fracture (both endplates)
6. Fracture Dislocation / Cord Injury
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Materials and Methods
• Driver Seated Position in the Car
– Series of Measurements (direct and indirect)
• Seated in the car in race trim
– Belts tightened
• HANS
• Helmet
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Materials and Methods
• X-ray Analysis of
Spinal contour in race
car
– Indy Pro Series tub
– X-rays obtained w/wo
HANS
•
•
•
•
Upright
Nose down
Nose up
Inverted
– Normal standing and
seated posture
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Materials and Methods
• Barrier Impact Test
– Fully loaded Indy Car
– Rearward into a rigid
barrier
– Hybrid III with HANS
and Helmet
– High speed video
– Multiple channels
– Multiple
accelerometers
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Materials and Methods
• HYGE Sled Tests
– Delphi – Vandalia OH
– 80 g pulse
– THOR ATD
• T8 and T12 load cells
• HANS
– Indy Car Posture
• Reclined 45°
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Material and Methods
• Computer Model
– MADYMO Full FE
Human body Model
• SAE MSEC # 2006-013659
– MADYMO Facet
Human Body Model
– Correlated with sled
test
– Validated
trt@motorsportsmd.com
Materials and Methods
In frontal
impact, up
to 30mph
THOR Physical dummy
Real
human
body
THOR dummy math model
At frontal and rear
impacts, under low
severity impacts
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Human Body math model
Results
• Fracture Data
• Seated Position
– Number
– Location
– Measurements from
driver in car
• HYGE sled tests
• Computer model
• Impact direction
– Classification
– Severity
• Barrier Impact Test
• Spinal Alignment
– X-ray analysis
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Results
Spinal Fractures
• 36 - drivers sustained spinal injury
• 38 - incidents resulted in spinal injury
• Two drivers with two separate incidents
• 54 - spinal levels injured
• 9 sustained injury at more than one level
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Results
Fracture Location
Region of Injury
14
13
12
12
10
9
8
6
4
4
3
2
0
Region
OCC
Cervical
Thoracic
3
9
12
ThoracoLumbar LumboSacral
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13
4
Results
Fracture Location
Cervical Fractures by Level
4.5
4
3.5
Number
3
2.5
2
1.5
1
0.5
0
O-C2
C3
C4
C5
Level
trt@motorsportsmd.com
C6
C7
Results
Fracture Location
Thoracic Fractures
4.5
4
3.5
Number
3
2.5
2
1.5
1
0.5
0
T2
T3
T4
T5
T6
Level
trt@motorsportsmd.com
T7
T8
T9
Results
Fracture Location
Thoracolumbar Fractures
8
7
6
Number
5
4
3
2
1
0
T10
T11
T12
Level
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L1
L2
Results
Fracture Location
Lumbosacral Fractures
2.5
2
1.5
1
0.5
0
L3
L4
L5
Level
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Sacrum
Results
Impact Direction
Impact Direction vs. Injury
25
20
15
10
5
0
Direction
Frontal
Rearward
Axial
Poly
7
25
3
3
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Results
Impact Direction v. Fracture Region
Impact Direction
8
7
6
5
4
3
2
Frontal
Rearward
Axial
Poly
Poly
Axial
Rearward
1
Frontal
L/S
ThoracoL
Thoracic
Cervical
OC
Fracture Region
0
OC
Fracture Region
Cervical
Thoracic
ThoracoL
L/S
Frontal
2
0
2
4
0
Rearward
1
8
7
8
3
Axial
0
0
3
0
0
Poly
0
1
0
0
1
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Results
Impact Direction
Impact Direction vs. Cervical Level
4
3.5
3
2.5
Number
2
Total Number
Rearward Impacts
1.5
1
0.5
0
O-C2
C3
C4
C5
C6
C7
Level
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Results
Impact Direction
Thoracolumbar Fractures: Impact Direction
Thoracic Fractures: Impact Direction
4
7
3.5
6
3
5
2.5
4
Number
2
All Fractures
Rearward
Axial Force Only
1.5
Number
All Fractures
Rearward Impact
3
2
1
1
0.5
0
T2
T3
T4
T5
T6
T7
T8
T9
0
T10
Level
trt@motorsportsmd.com
T11
T12
Level
L1
L2
Results
• Data Segregation
– Study of thoracic and thoraco- lumbar
fractures
– Fractures resulting from rearward impacts
• 22 cases (drivers injured)
– 13 incidents of thoracic and thoracolumbar fractures
» 19 levels fractured
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Results
Fracture Classification:
Comprehensive Classification System
Gertzbein in Controversies in Spine Surgery
Vol 1, 1999
trt@motorsportsmd.com
Results
Fracture Type by Direction of Impact
Rearward
Frontal
Type B2
Flexion Axial Compression
Type A1
Axial Compression
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Results
Classification of Fractures from Rearward Impacts
• All Type A – Vertebral Body Compression
– Group 1 Impaction Fracture
-11
• Subgroup 1 End Plate Infraction – 4
• Subgroup 3 Wedge impaction
-7
– Group 3 Burst Fracture
• Subgroup 1 Partial burst
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- 2
The Injury
FRACTURE SEVERITY CLASSIFICATION
Type 1: Vertebral compression without deformity
Only present on MRI seen best in T2 sagittal
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The Injury
Type 2: <10% Comp; <15°
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The Injury
Type 3: >10%<30%
compression;>15°<30°
26% & 27°
*
38% & 14°
Type 4: ≥ 30% ≥ 30° ± posterior injury
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The Injury
Type 6: Fracture dislocation
T12 Burst Fracture
>50% compression
Type 5: Burst Fracture
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Results
Injury Severity
Severity vs. Direction
5
4.5
4
3.5
3
2.5
2
1.5
T-3 -9
T11 - L1
1
0.5
T11 - L1
0
Overall
forward
rearward
Severity
T-3 -9
axial
Overall Severity
forward
rearward
axial
T-3 -9
3.2
4.5
2.4
3.7
T11 - L1
3.8
5
3.3
0
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The Focus
REARWARD IMPACTS
• 67% of the injuries
• 63% levels injured
• 2.9 ave.severity
index
• (frontal = 4.8)
• Large database
trt@motorsportsmd.com
Accident Analysis
Analysis of Crash Videos
and ADR data
+ x g’s = 60
-z g’s = 25
Δ V = 68 mph
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Accident Analysis
A Group 1 Type 4
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Accident Analysis
ADR – 2 Data
• 13 incidents of rearward impact with Th
and T/L spinal fractures
– Average
ΔV
67
G’s
x
z
72
43
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Barrier Impact Test
50 mph cv (80kph) ; +x g’s = 146.5
-z g’s = 44.6
Pelvic displacement = 4.7 inches
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Driver Position in Race Car
MEASUREMENTS
• Driver height
• Below roll hoop
• Forward of roll hoop
• Faceplate to steering
wheel
• Chest to steering wheel
• Height above surround at
visor pivot
• HANS to helmet
trt@motorsportsmd.com
H
V
Visor
Ch
HANS to Helmet
P
es
t
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Height
69.1
Rollbar V
14.8
Rollbar H
7.8
Pivot
2.0
Visor
13.2
Chest
13.6
HANS
1.1
Spinal Contour
Spine X-rays in tub with and without
HANS in 4 orientations
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Spinal Contour
X-ray
acquisition
and
analysis
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Spinal Contour
Normal
Seated in race
car
Th Kyphosis 59°
Th Kyphosis 20° 50°
T10 – L2 0°
Lumbar Lordosis
40° - 80°
55°
5
-13°
T10 – L2 +17°
(kyphosis)
Lumbar Lordosis
- 5°
-40°
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Spinal Contour
SEAT CONTOUR and ALIGNMENT
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Seat Contours
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HYGE Sled Testing
ATD CALIBRATION & VALIDATION
Hybrid III
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THOR
HYGE Sled Testing
New Sled Buck
designed and built to
accommodate
• THOR
• Variable seat back
angle
• Thigh – torso angle
• Complete visibility of
ATD
HyG Sled buck for THOR and variable seat
back angle and thigh torso angle
trt@motorsportsmd.com
HYGE Sled Testing
Test# IS66F010
Rear Impact Sled Test With 6pt Belts
ThorFtLowerSpine Rev 1
Released By: M.Shipp
T-8_X_Y_Z [N]
Test Type: Frontal Sled
ATD Position: Front Row Left
ATD Type: THOR
5000
Process Date: 06.29.2006
(X)-Force X Max.: 1.326E+02[N]
Time of Max. X: 0.0461[Sec]
(X)-Force X Min.: -6.944E+03[N]
Time of Min. X.: 0.0260[Sec]
0
(+)-Force Y Max.: 4.087E+02[N]
Time of Max. Y: 0.0227[Sec]
(+)-Force Y Min.: -2.096E+03[N]
Time of Min. Y.: 0.0247[Sec]
(*)-Force Z Max.: 8.218E+02[N]
Time of Max. Z: 0.0465[Sec]
(*)-Force Z Min.: -1.933E+04[N]
Time of Min. Z.: 0.0261[Sec]
-5000
-10000
CAC:
Filter Class: CFC1000
0
Released By: WT
Test Type: Frontal Sled
ATD Position: Buck/All Positions
Std Pulse: PlsI107
Sled_X [G's]
20
0.02
iftS
6
ltLd
3S
1
A
5
1
A1
O
E2
J0
5S
7
18
727
8
ht
3S
3
41
0
IH
T
FtRL
3
1
2
Ct
I0
C
6S
187li0H
6N
0R
90C
V
R
2
4
5
7
3
IRL Rear Impact, Pulse 107, THOR
SledChk Rev 5
Test# IS66F010
8360N
-20000
Test# IS56F031
0.04
0.06
0.1
0.08
0.12
0.14
0.16
0.2
0.18
Time [Sec]
Page _____ of______
-15000
Thor T8 Load Cell
Process Date: 07.01.2005
Test# IS66F010
(+)Le Re Accel. Max.: 2.2[G's]
Time of Max.Acc: 0.0806[Sec]
Le Re Accel. Min.: -73.3[G's]
Time of Min.Acc: 0.0135[Sec]
Rear Impact Sled Test With 6pt Belts
ThorFtLowerSpine Rev 1
0
Released By: M.Shipp
(*)Std Pulse Accel. Max.: 0.0[G's]
Time of Max.Acc: 0.0000[Sec]
T-12_X_Y_Z [N]
-20
Test Type: Frontal Sled
ATD Position: Front Row Left
ATD Type: THOR
5000
Std Pulse Accel. Min.: -82.1[G's]
Time of Min.Acc: 0.0121[Sec]
Process Date: 06.29.2006
(X)-Force X Max.: 3.503E+02[N]
Time of Max. X: 0.0418[Sec]
(X)-Force X Min.: -2.810E+03[N]
Time of Min. X.: 0.0309[Sec]
0
(+)-Force Y Max.: 7.912E+01[N]
Time of Max. Y: 0.0225[Sec]
(+)-Force Y Min.: -6.915E+02[N]
Time of Min. Y.: 0.0240[Sec]
(*)-Force Z Max.: 2.367E+03[N]
Time of Max. Z: 0.0462[Sec]
-40
(*)-Force Z Min.: -1.991E+04[N]
Time of Min. Z.: 0.0280[Sec]
-5000
-60
80g’s +x
CFC60
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.2
0.18
Time [Sec]
Indy Car Rear Impact Pulse
-15000
8430N
-20000
0
trt@motorsportsmd.com
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
Time [Sec]
Thor T12 Load Cell
Test# IS66F010
0.02
CAC:
Filter Class: CFC1000
Page _____ of______
0
Test# IS56F031
-100
Page _____ of______
-80
-10000
CAC:
Computer Modeling
COMPUTER MODELING
• Review past work
• Validation and
refinement
– SAE papers on FE
model
• Integration of known
parameters
– Schmidt Thesis
• Acquisition of
• Model refinement
software
•
Model
development
• Sled – Model
integration
• Model Behavior with
variable modification
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Computer Modeling
Full MADYMO FE HBM
• Unable to allow
IndyCar Seating
position (SAE 2006 01 -3659)
MADYMO Facet Model
• Adapted to position of
the reclined driver
posture
• Reliable at high g’s
MADYMO Facet Human Body Model
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Computer Modeling
Facet Model demonstrated large z loads at
all vertebral levels with applied pulse in the
+x direction
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HBM Positioning
•HBM Positioning by Rotating the
Whole body
•Pre-positioned HBM From TASS
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Result Analysis – Overall Occupant
Kinematics
•HBM Positioning by Rotating the
Whole body
•Pre-positioned HBM From TASS
Movie
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Result Analysis – Overall Occupant
Kinematics
•HBM Positioning by Rotating the
Whole body
•Pre-positioned HBM From TASS
Movie
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Result Analysis – Overall Occupant
Kinematics
•T=0ms
•T=3ms
•T=6ms
•T=35ms
•Note: All vertebrae are made of rigid elements, no
deformation, no stress and strain outputs
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Result Analysis – Acceleration
Comparison
•
The acceleration curves from the THOR dummy
sled test only as a reference point for the HBM
responses.
–
–
•
•
THOR dummy math model outputs expected to match
dummy sled test outputs
The HBM outputs not expected to match those of the
THOR dummy sled test or dummy math model
General trend of HBM accelerations reasonable
Rock-and-roll spinal motion resulting in unrealistic
pelvis acc
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Result Analysis – Numerical
Stability
•
Pre-positioned model
becoming unstable
after 35ms
– Excessive element
deformation
– Penetrations among
the internal organs,
the skeleton and the
skin
– Elbow joint dislocation
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Computer Modeling
THUMS
• Total Human Model for Safety
Toyota Motor Corporation
Toyota Central Research and Development Laboratory
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Validation
Toyota FIA Modeling Project Cooperative with THUMS
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Discussion
PATHOPHYSIOLOGY • Superior endplate
failed most commonly
• Load required to
produce fracture
• Wedging
• Effect of rate of
application
• Effect of position
– Degree of flexion
trt@motorsportsmd.com
Discussion
Loads to failure for Endplate and Vertebral
Body were rate dependant
– Higher velocity loading resulted in increased
likelihood of fracture
– Loads from 2500N - 6000N
– Thoracic Vertebral Fractures 4200N – 7600N
• Dependent on the age of the specimen
trt@motorsportsmd.com
Discussion
Type and Severity of Fx Effect of loading rate
• Force
on endplate and
– Magnitude
vertebral body
– Point of application
strength in human
– Rate of application
lumbar vertebrae
– Associated moment
• Ochia, R., Tencer, A.
& Ching, R.
• Direction
– +x (rearward)
Journal of
– -y (axial compression)
Biomechanics
36 (2003) 1875-1881
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Discussion
Major Injury Vector
• Major Injury Vector
– Compression loading
of the end plate
• z axis (axial)
– Fracture types from
rearward impacts are
variants of axial
loading with some
flexion moment
trt@motorsportsmd.com
Discussion
EJECTION SEAT INJURY STUDIES
Biomechanics of fracture
• Load path
– z axis
•
Magnitude of load
– >20 g’s
•
Rise time (rate)
**
– Crash pulse
• Canon shell
• Rocket motor
•
Spatial orientation of the
vertebral column
– out of position spinal
flexion
•
Dampening effect of the
seat material
Eccentric Load vs Facet Rotation *
trt@motorsportsmd.com
Discussion
Common Factors
ejection vs. race car
• Fracture type
• Fracture severity
• Anatomical location
– Mid Thoracic
– Upper Lumbar
• Posture at impact
– Out of position
– Indy Car posture
trt@motorsportsmd.com
Discussion
EJECTION SEAT INJURIES
Spatial Orientation
• Normal contours
– Thoracic kyphosis
– Lumbar lordosis
• Straight spine
• Thigh – Trunk angle
– 135°
• Pelvis anchored
INJURY LEVELS
• Mid thoracic spine
• Compression
• Fractures less likely
when spine
extended
– Thoracolumbar
contour preserved
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Discussion
Risk of Fracture Reduced
• Maintaining physiologic
posture
– Contact with seat back
• Altered position of ejection
lever
– Anchoring pelvis
– Thigh – torso angle
• 135°
• Reducing rate of force
application <20g’s
– Limiting rise time with
rocket
– Seat cushion material
trt@motorsportsmd.com
Discussion
Results of Previous Modeling
Optimum Position for Rearward Impact
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Discussion
Driver Kinematics
• Forward rotation of torso
– Out of position seating
• Ramping phenomenon
– Video analysis
– Rear impact barrier test
– HYGE sled tests
• Viano effect
trt@motorsportsmd.com
Discussion
• Compressive Loads
– Ramping with inertial
loading
• Torso rise
• Frontal rise on impact
– Straightening of
thoracic kyphosis
• Viano data
VIANO EFFECT: Impact applied to the
thoracic kyphosis resulted in straightening
of the spine and a compressive load on
the spine remote from the point of force
application
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Discussion
THOR in HYGE Sled
• z (axial) loads
produced in rearward
impact (+x)
– T8 and T12 load cells
• Ramping
Model Validation
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Discussion
Seated Position
Upright seated posture in aircraft ejection and preservation
of physiologic contours reduced fracture risk
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The Mechanism
Seating Position Confirmed by xray
analysis and seat contour
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Discussion
Environmental Limitations
• Cockpit /Monocoque
dimensions fixed
• Maximum driver
height below roll hoop
• Driver size
– Anthropometry
• Height 67.9 inches
• Weight 164.5#
• Seated height 35.2 in
trt@motorsportsmd.com
Discussion
Variation in Fx Level
• Load Path
– ADR shows -z loads
– Rear crash test high z
loads (compressive)
– Injuries consistent with
z loading
• Rear Crash test
demonstrated chassis
buckling and rise
trt@motorsportsmd.com
Discussion
Variation in Fx Level
• Load Path
– ADR shows -z loads
– Rear crash test high z
loads (compressive)
– Injuries consistent with
z loading
• Rear Crash test
demonstrated chassis
buckling and rise
trt@motorsportsmd.com
Discussion
Variation in Fx Level
• Load Path
– ADR shows -z loads
– Rear crash test high z
loads (compressive)
– Injuries consistent with
z loading
• Rear Crash test
demonstrated chassis
buckling and rise
trt@motorsportsmd.com
Conclusions
•
Spinal fractures
occurrence
increasing
– 8.5% to 21%
•
•
71.4% in rearward
impacts (+x)
All fractures MIV is
in z axis (axial
compression)
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Conclusions
• Rearward (+x) impact generates a
compressive (z) in the driver’s spine
–
–
–
–
–
ADR-2 chassis accelerometer (z)
ADR-2 ear accelerometer (z)
Barrier Impact test with Hybrid III ATD
HYGE sled test with THOR ATD
MADYMO Facet HBM
• Load is sufficient to produce fracture
– ≥ 6000N or 20g’s vertical
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Conclusions
• X-ray Analysis of Driver in Car
– Loss of normal spinal contours
• Loss of lumbar and cervical lordosis
• Accentuated Thoracic Kyphosis
• Thoracolumbar kyphosis
– Pre loads vertebral endplate
• Hydrostatic property of intervertebral
disc
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Conclusions
• Development of Spinal Compressive (z)
loads is multifactoral
– Spinal alignment
– Ramping of the torso
– “Viano effect”
– Frontal rise of vehicle during impact
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Conclusions
• Interaction of torso
with the seat
– Material
characteristics
• Energy management
• Variable density
– Control ramping
• Pelvic anchorage
• Promote/maintain
lumbar lordosis
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Conclusions
Goal of Study to reduce
• Compressive loading of ≤ 6500 N
• Vertical g’s < 20 g’s
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HYGE Sled Testing
New Sled Buck
designed and built to
accommodate
• THOR
• Variable seat back
angle
• Thigh – torso angle
• Complete visibility of
ATD
HyG Sled buck for THOR and variable seat
back angle and thigh torso angle
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Seat Modification
EPP 1.76# IS64f030 – 66F012
Drilled IS66F013 – 67F012
EAR foam added IS68F025
With
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pelvic void IS68F028
Seat Modification
EEP 1.76# with carve out IS72F022
With EPS 1.5# IS72F024
Posterior Void filled IS72F25 - 26
Carbon Kevlar unsupported ISbF024
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Seat Modification
Hyge Sled Testing Rearward impact
Test No. T1 G's Z
IS64F029
44.2
IS65F005
56.5
IS66F010
114.8
IS66F011
x
IS66F012
-469.9
IS66F013
-179.0
IS67F002
-392.0
IS68F025
-74.7
IS68F026
-27.2
IS69F012
52.7
IS69F013
-95.2
IS6BF024
33.8
T8 Z (N) 8 MnY (Nm T12 Z (N) T12 MnY (Nm)
-6444.0
-623.0
6965.00
-207.0
-11080.0
-571.0 11170.00
-81.3
-19330.0
-679.0 -20000.00
-123.4
-17890.0
-773.0 -14690.00
-123.0
-18700.0 -1008.0 -16025.00
-147.0
5012.0
-661.0
-5400.00
-150.0
-15480.0
-555.0 -15210.00
-80.6
-13130.0
-474.0
-9460.00
-21.0
-5356.0
-465.0
-6300.00
-118.0
-11050.0
-178.0
-7335.00
296.0
-15000.0
-460.0 -10230.00
-67.6
-5222.0
37.5
-3300.00
151.0
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Progress Report
Past Testing and Analysis
• EPS and EPP testing
– Seat back too stiff (hard)
– Unable to manage energy
• Ramping
• Thoracic straightening
– Loads in excess of limits
• Drilled out seat to soften
– Results improved
• Belt Geometry alterations
– 7 point most effective
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Progress Report
Testing in February 2007
• Proof of Concept
– Carbon – Kevlar Shell
– Foam backed
• Reduced loads
– T8 z’s = 7500
– T12 z’s = 4700
• Excessive excursion
– Available space ~ 2 in
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Progress Report
Testing in June 2007
• New Bracket design
– All restraint harness
anchor points out of
position relative to
ATD
– Invalid tests !
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Progress Report
Testing in August 2007
• 8 sled runs
– EPS seats from Mk – 1
• Corrugated
– EPP seats from Createc
– Modular backing
• Fenestrated
• Corrugated
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Progress Report
Results:
• Data wouldn’t trend
– T8 & T12 loads
remarkable similar
regardless of condition
• Unpredictable effects
of seat modification
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Progress Report
Analysis of Results
• ATD unsupported by
seatback
• Lack of contact due to
error in original seat
molding - pour
• Original mold used to
form all subsequent seats
• All tests to date
unrepresentative of actual
event
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The Problem
New Spine Fx’s in
2007
1 – IRL
2 – IPS
2 – Champ Car
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Progress Report
• New seat mold made for THOR
• Bald Spot / Createc and Mk-1 have use of
mold
– Both have fabricated new seats with accurate
fit to THOR
• Carbon – Kevlar shell
• EPS and EPP backing and seats
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Progress Report
Sled Testing at CAPE (preliminary results)
• 6 rearward runs
–
–
–
–
–
BSS Mk -1 BSS Mk- 1 Mk- 1 -
1.7# EPP
1.5# EPS
1.0# EPS
1.5# EPS with Carbon Shell
0.5” EPS beads
• All performed below fracture threshold, issues
with motion and undesirable loading
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Progress Report
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Progress Report
T8 X (N)
-5717.5
-1033.6
-1947.6
-1229.6
991.2
-1351.1
T8 Z (N) T8 MnY (Nm) T12 X (N)
-15698.4
-4155.2
-5568.8
-3587.8
-4788.5
-6093.0
-711.2
-596.8
-346.5
-536.4
-211.8
-148.4
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-2680.1
-2646.0
-1665.0
-2289.4
-692.6
719.5
T12 Z (N)
-7901.00
-5565.30
-6043.90
-4089.20
-4539.20
-5424.60
Progress Report
Summary
• Injury mechanism validated
– Clinical review, sled test analysis, THUMS
• Seating platform design
– Seat parameters defined
• Softer seat with better energy management to
capture pelvis and prevent ramping
• Design to lessens loads below threshold as yet
unidentified
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Guidelines
• Obtain Seat from either Bald Spot Sports
or Mark 1 Composites
– DO NOT MAKE IT YOURSELF from 2 part
foam
• Don’t press yourself into the mold when
making seat – try to maintain normal
contour
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Desired Seat Contour
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Guidelines
• 2 inch minimum thickness of the back
• 1 inch minimum thickness of the bottom
• High friction surface
– Don’t cover the seat with glossy duct tape
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Guidelines
• Restraints
– Use a 7th center belt
– Use the Schroth HANS 2” over 3” shoulder
belts (HANS goes between the belts)
• Protect your knees
– Pad the forward side of the dash bulkhead
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Goal of Project
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Goal of Project
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Goal of Project
A
Happy
Ending
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The End
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