A Component Head Injury Criteria Tester for Aerospace
Applications
Hamid LankaraniNational Institute for Aviation Research
Wichita State UniversityEmail: [email protected]
Fire & Cabin Safety Research ConferenceAtlantic City, New Jersey
October 22-25, 2001
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Problem Statement
The compliance with the Head Injury Criteria (HIC) poses a significant problem for aerospace industry
Where, a(t) is the head resultant acceleration of the Part 572 Hybrid IIATD in g’s and t1 and t2 are the response times to maximize the function.
Non injurious if: HIC < 1000
( ) ( )max
5.2t
t1212
2
1
)t(att
1ttHIC
∫−
−=
HIC problem encountered in:
Bulkhead Class Dividers Cabin Furnishings Cockpit Glare Shields Cabin Side Walls Row-to-Row Instrument Panel Entry Door Steps Wind Screen Posts/Side Posts
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Problems Related To Dynamic Full-scale Sled Tests
Difficult to identify and test the critical conditionsSeveral test articles are destroyed to certify one test conditionRequire large flow timeInherent variations in sled test data may result in excessive HIC scatterAssociated with significant cost
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Component Level Testers
Advantages Easier to setupShorter flow timeEffective product development tool Cost effectiveAppropriate for identifying critical impact location(s)
Validation CriteriaHICHIC window, ∆t = t2 – t1Average head C.G. accelerationGeneral form of the head acceleration time history
GoalDevelop an enhanced component test method as an alternate procedure to support HIC compliance for front row bulkhead seating
Fire & Cabin Safety Research Conference October 22 – 25, 2001
ATD Kinematics During a 16g Dynamic Test
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Component HIC Test Devices
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Evaluation of Component HIC Test Devices
The component HIC test devices provide reasonable correlation compared with the 16g dynamic full-scale sled tests only for
Configurations with dominantly normal head impact velocity (short distances to impact surface) Relatively short duration impacts(relatively hard surfaces) Properly utilized system effective masses
Factors affecting these differences may include:articulation of other body segments for the ATD belt compliance & motion (translation) of the pelvisfriction of the pelvic/seat and head/frontal-structure
The HIC window t = t2 – t1 is usually much smaller for all the component HIC testers compared to the results from dynamic sled tests
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Methodology
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Design of an Inverted Pendulum Device
Production Bulkhead
16.2 in.Length of Pendulum
63.5 lbSum of Upper Torso, Arms, and Hands
Seat Setback Seat Reference Point
Seat
Hybrid II Head-neck Assembly
Hybrid II ATD
Inverted Pendulum model
Revolute Joint
88.2 lbSum of Lower Torso, Upper and Lower Legs, and Feet
Inverted Pendulum ModelFull-scale Model
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Qualification Test with Inverted Pendulum Setup
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Comparison of Results
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Adjustments in Design Based on Madymo Analysis
Hybrid II Head –neck Assembly
28.8 kg (63.5 lb)Sum of spine , Upper
Torso and Hands
40 kg (88.2 lb)Sum of Lower Torso , Upper
Lower Legs, and Feet
Hybrid II Head –neck Assembly
10 kg (22.2 lb)Pendulum Arm
64 kg (141.1 lb)Lower Torso
Initial design based on ATD weight distribution.
Weight distribution based on Madymo analysis.
Design Iteration/ Parametric Study
0.412 m (16.2 in.)
0.508 m (20 in.)
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Final Design of the Component HIC Tester
Rear Torso
Support ArmHead Top Actuator
Pendulum Arm Actuator Stand
Linear Bearings
Sliding plateLower Torso
ProEngineer Model of Component HIC Tester
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Fabricated Component HIC Tester
Support Arm Extension
Top Actuator
Support Arm
Top Actuator Stand
Pendulum Arm
Lower Torso
Slide Plate
Base Plate
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Operation of NIAR’s Component HIC Tester
Mode:1Lower torso constrained in the forward directionLower torso allowed to snap backward at the time of impact and resisted by springs/dampers, or crushable honeycombOperated only by top actuator
Mode:2Fixed lower torso (similar to MGA device)Operated only by top actuator
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Operating Methodology of Component HIC Tester
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Component HIC Test Methodology – Flow Chart
Conduct a baseline dynamic sled test with Hybrid II ATD for a particular seat setback distance, restraint system and bulkhead
Note all the test setup conditionsCollect the evaluation criteria data from full-scale test like head C.G acceleration profile, head impact angle, head impact velocity, HIC window
Conduct a test with Component HIC tester in Mode-I/II condition with the same test conditions used for the full-scale sled test
Note all the test setup conditionsCollect all the critical data from component tester like head C.G acceleration profile, head impact angle, head impact velocity, HIC window
Compare the obtained data form sled test and component test for the evaluation criteria
Does data correlate?
Yes
No
Component HIC tester calibrated in Mode-I/II by checking for repeatability and for different seat setback distance, restraint system and bulkheads
Vary parameters such as actuator pressure, pendulum
arm length
Fire & Cabin Safety Research Conference October 22 – 25, 2001
MODE-I: Calibration Tests with Aluminum Bulkhead
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Calibration of MODE-I Tests with Full-Scale Sled Test
Description Full-Scale Test#96288-004
CompHIC Test#01057-24
CompHIC Test#01057-25
HIC 694 676 703 Head impact angle (deg) 38 37 37.5
Head impact velocity (fps) 45.1 41.0 44.0 HIC window (ms) 23.7 20.0 22.5
Head CG peak acceleration (g’s) 142.5 145.0 142.9
Head CG average acceleration (g’s) 61.0 64.0 62.5
2.78 2.79 2.8 2.81 2.82 2.83 2.84 2.85 2.86Time (s ec)
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HeadCGResultantAcceleration(g's)
S led Te s t Data (Tes t#96288-004)Component Te s t Data (Tes t#01057-24)S led Contact S tartS led Contact EndComponent Contact S tartComponent Contact Endtc1ts1ts2tc2
MODE-IValidation Tes t 01057-24(35 inch Seat S e tback, Aluminum 2024-O Bulkhead)
ts1=2.7925sec
TSe=2.8565sec
tc1=2.7924sec
TCs=2.8404sec
tc2=2.8124sec
ts2=2.8162sec
TCs=2.7924sec
TSs=2.7925sec
2.79 2.8 2.81 2.82Time (s ec)
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HeadCGResultantAcceleration(g's)
S led Tes t DataComponent Tes t DataTs1Ts2Tc1Tc2
MODE-IValidation Tes t 01057-24(35 inch Seat Setback, Aluminum 2024-O Bulkhead)
Ts1=2.7926sec
Ts2=2.8163sec
Tc1=2.7924sec
Tc2=2.8124sec
Fire & Cabin Safety Research Conference October 22 – 25, 2001
MODE-I Repeatability
1.49 1.495 1.5 1.505 1.51Time (s ec)
10
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50
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HeadCGResultantAcceleration(g's)
Component Tes t#01057-24Component Tes t#01057-25
MODE-IRepeatability Tes t 01057-24 &Tes t 01057-25(35 inch S eat S e tback, Aluminum 2024-O Bulkhead)
Repeatability Plot
1.471.4751.481.4851.491.4951.51.5051.511.5151.521.5251.531.5351.541.5451.55Time (s ec)
10
20
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HeadCGResultantAcceleration(g's)
Component Tes t#01057-24Component Tes t#01057-25
MODE-IRepeatability Tes t 01057-24 &Tes t 01057-25(35 inch S eat S e tback, Aluminum 2024-O Bulkhead)
Fire & Cabin Safety Research Conference October 22 – 25, 2001
MODE-II: Calibration Tests with Aluminum Bulkhead
Full-Scale Sled Test#96288-004
Calibration Test#01057-28
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Calibration of MODE-II Tests with Full-Scale Sled Test
Description Full-Scale Test#96288-004
CompHIC Test#01057-27
CompHIC Test#01057-29
HIC 694 677 700 Head impact angle (deg) 38 38 37
Head impact velocity (fps) 45 46 46 HIC window (ms) 23.7 24.3 29
Head CG peak acceleration (g’s) 142.5 142 139
Head CG average acceleration (g’s) 61 g 65.7 60
2.78 2.79 2.8 2.81 2.82 2.83 2.84 2.85 2.86Time (s ec)
0
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HeadCGResultantAcceleration(g's)
S led Tes t DataComponent Te s t DataS led Contact S tartS led Contact EndComponent Contact EndComponent Contact S tartts 1tc1ts 2tc2
MODE-IIValidation Tes t 01057-27(35 inch S eat S e tback, Aluminum 2024-O Bulkhead)
TSs=2.7925sec
TSe=2.8565sec
TCs=2.7925sec
TCe=2.8387sec
tc1=2.7925sec
ts1=2.7925sec
ts2=2.8162sec
tc2=2.8168sec
2.79 2.8 2.81 2.82Time (s ec)
0
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HeadCGResultantAcceleration(g's)
S led Tes t DataComponent Tes t DataTs1Ts2
MODE-IIValidation Tes t 01057-27(35 inch S eat S e tback, Aluminum 2024-O Bulkhead)
Ts1=2.7926sec
Ts2=2.8163sec
Fire & Cabin Safety Research Conference October 22 – 25, 2001
MODE-II Repeatability
Repeatability Plot
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Comparison Of The Component HIC Test Data With MGA Test
CORRELATION OF MGA TEST 197011 AND NIAR ENHANCED COMPONENT HIC TEST 01057-25 WITH SLED TEST
Fire & Cabin Safety Research Conference October 22 – 25, 2001
MODE-I: Calibration Tests with Honeycomb Bulkhead
Full-Scale Sled Test# 01008-008
Calibration Test# 01057-43
Fire & Cabin Safety Research Conference October 22 – 25, 2001
MODE-I: Calibration Tests with Honeycomb Bulkhead
Description Full-Scale Test#01008-008
CompHIC Test#01057-43
CompHIC Test#01057-44
HIC 862 834 980 Head impact angle (deg) 38 38 38
Head impact velocity (fps) 44.0 40.3 41.0 HIC window (ms) 28.7 32.9 31.8
Head CG peak acceleration (g’s) 132.3 131.0 134.0
Head CG average acceleration (g’s) 61.0 58.0 62.5
3.18 3.2 3.22 3.24 3.26 3.28 3.3Time (s ec)
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HeadC.GresultantAcceleration(g's)
Component Tes t# 01057-43S led Tes t# 01008-008Ts1Ts2Tc1Tc2
Mode - IValidation Tes t 01057-43(35 in. s eat s e tback dis tance , Nomex Honeycomb pane l)
Ts1=3.200sec
Ts2=3.302sc
Tc1=3.2089sec
Tc2=3.2469sec
e c
3.18 3.2 3.22 3.24 3.26 3.28 3.3Time (s ec)
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HeadC.GresultantAcceleration(g's)
Component Te s tS led te s tS led Contact S tartS led Contact EndComponent Contact S tartComponent Contact Endts1ts2tc1tc2
Mode - IValidation Tes t 01057-43(35 in. s eat s e tback dis tance , Nomex Honeycomb pane l)
TSs=3.2000se
TSe=3.302sec
TCs=3.2089sec
TCe=3.2469sec
ts1=3.2000sec
ts2=3.2328sec
tc1=3.2089sec
tc2=3.2418sec
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Pressure – Velocity Calibration Charts
25 30 35 40 45 50Head Impact Ve locity (ft/s ec)
90100110120130140150160170180190200210220230240250
ActuatorPressure(psi)
P = 0.2917V2 - 15.4996V +296.0768
25 30 35 40 45 50Head Impact Ve locity (ft/s e c)
60708090
100110120130140150160170180190200210220230240250260
ActuatorPressure(psi)
P = 0.3471V2 - 18.6858V +322.0912
25 30 35 40 45 50Head Impact Ve locity (ft/s e c)
30405060708090
100110120130140150160170180190200
ActuatorPressure(psi)
P = -0.0091V2 + 7.4019V -147.988
35 degrees 40 degrees 45 degrees
20 25 30 35 40 45 50Head Impact Ve locity (ft/s e c)
405060708090
100110120130140150160170180190200210220230240250260
ActuatorPressure(psi)
P = 0.2538V2 - 10.5720V + 155.1803
25 30 35 40 45 50Head Impact Ve locity (ft/s ec)
60
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90
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120
130
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150
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ActuatorPressure(psi)
P = 0.0098V2 + 4.4262V - 60.0306
25 30 35 40 45 50Head Impact Ve locity (ft/s e c)
30405060708090
100110120130140150160170180190200210220230240250
ActuatorPressure(psi)
P = 0.0871V2 + 1.6739V - 59.3593
50 degrees 55 degrees 60 degrees
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Concluding Remarks
A component HIC tester was designed, fabricated and tested for aerospace applications.
Calibration of the device was conducted for aluminum and honeycomb-type bulkheads.
Preliminary tests of the NIAR component HIC tester have shownpromising results.
Pressure-velocity calibration charts have been developed. The charts are independent of the physical characteristics and surface treatment of the bulkhead.
Preliminary tests with aluminum bulkheads at small and large seat setback distances have indicated that the device can be used with reasonably good correlation in Mode-1 for small head impact angles (less than 40 degrees) and in Mode-II for high head impact angles (greater than 40 degrees).
The system will be enhanced to have a representation of the upper torso restraint system or at least calibrated for the presence of the upper torso system.
Fire & Cabin Safety Research Conference October 22 – 25, 2001
Concluding Remarks
A range of impact angles and velocities from the dynamic sled tests will be used for calibration of the device.
The system will also be evaluated for the seating configurations utilizingtypical airline seats rather than iron seats.
Other bulkhead types and surface treatments will also be considered and the system will be evaluated for these bulkhead types.
The system will also be calibrated for Part 23 applications.
Project will deliver a tool that can be utilized to easily identify potential solutions for bulkhead HIC problem.
The component HIC tester will offer the capability of evaluating different designs and/or test conditions at relatively low cost and short period of time.
Detailed test methodology and guidelines for the use of the system as an eventual compliance test method is being developed.