Post on 03-Jun-2018
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
1/27
Analysis of a FrontalImpact of a Formula
SAE VehicleDavid RisingJason KaneNick Vernon
Joseph AdkinsDr. Craig Hoff
Dr. Janet Brelin-Fornari
Kettering University
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
2/27
Overview
Introduction
Formula SAE Impact Attenuator Rules Methodology
Evaluation Criteria HIC, Neck Loads and Moments, Nij, Femur Loads
Testing Procedures Baseline Testing, Pulse Shape Comparison, Critical Speed Test
Results Comparison of evaluation criteria
Kinematic Analysis using high speed video Conclusions
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
3/27
Introduction - Formula SAE
Worldwide collegiate
competition
Students conceive,design, and fabricate
small formula style cars Driver risks have never
been tested in a crash
environment
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
4/27
Introduction - Formula SAE ImpactAttenuator Rules
3.3.6.4 Impact Attenuator Data Requirement
The team must submit calculations and/or test data toshow that their Impact Attenuator, when mounted on the
front of the vehicle with a total mass of 300 kgs (661 lbs)and run into a solid, non-yielding impact barrier with a
velocity of impact of 7.0 m/s (23 ft/s), would give andaverage deceleration of the vehicle not to exceed 20 g.
Does not specify deceleration time-history pulse
shape
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
5/27
Introduction Methodology
Evaluate the Impact
Attenuator rule based onATD Injury Criteria Explore the Safety
Envelope by increasingimpact speeds
Evaluate Pulse Shape Kinematic Analysis Using
High Speed Video Evaluate HANS Device
Effectiveness
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
6/27
Typical Test
Test Conditions
7.0 m/s
16.5 g avg 35 ms
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
7/27
Evaluation Criteria - HIC
Head Injury Criteria (HIC) is used to evaluate the
severity of head trauma based on accelerations
HIC consists of two criterion, HIC36 and HIC15 HIC36 and HIC15 calculate the highest average
acceleration over a 36 ms and 15 ms periodrespectively
Values for HIC36 that exceed 1000 and values of
HIC15 that exceed 700 represent a 31% chance ofskull fracture
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
8/27
Evaluation Criteria - Nij
Nij criteria is based on the resultant neck loads and
moments experienced by the ATD Nij represents the four major combinations of neck
loading in a frontal crash Nce: Compression load and Extension moment
Ncf: Compression load and Flexion moment Nte: Tension load and Extension moment Ntf: Tensions load and Flexion moment
Nij values that exceed 1.0 and individual load and
moment values that exceed their IARV represent a22% chance of AIS 3 neck injury
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
9/27
Evaluation Criteria - Femur
Axial load cell in femur measurescompression and tension loads
Axial loads that exceed 10,000 N represent a
35% chance of a moderate injury to the femur
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
10/27
Procedure
Baseline Test Replicate as close as possible the deceleration due to the impact attenuator:
7.0 m/s, 20 g average, 35 ms pulse Pulse Shape Comparison
Increased speed to 12.5 m/s, average of 16 g, 80 ms pulse Three pulse shapes compared: early high-g peak, constant g, and late high-
g peak
Each pulse shape compared both with and without the use of a HANSdevice
Critical Speed Test Increased impact speed until Injury Assessment Reference Values were
exceeded Test specifications: 15.6 m/s, 80 ms pulse, 20 g average deceleration
Utilized late high-g pulse shape and was tested with and without HANS
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
11/27
Early High-g Pulse
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
12/27
Constant-g Pulse
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
13/27
Late High-g Pulse
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
14/27
Results Baseline
Showed no condition where IARV were exceeded
Test one, two, and three values were negligiblewhen compared to the IARV
Many values in test four were much closer to the
IARV May be due to much higher initial velocity (11.2 m/s) and
average deceleration (27.6) than tests one, two, andthree
Femur load cell was not utilized
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
15/27
Results - Baseline
-224394.869.50.66900.9620.293-101.197.47-413.4234611.227.6Baseline Test #4
-43.443.436.20.1580.0290.2960.200-32.4533.1-449.1394.56.916.6Baseline Test #3
-2839.930.60.1710.0570.2660.230-31.4135.14-475.3379.37.116.7Baseline Test #2
----0.1650.0570.2140.240-25.3534.17-413.7381.76.915.7Baseline Test #1
1000070010001111-135310-40004170IARV
AxialFemurLoad(N)
HIC15
HIC36
PeakR
esultantHeadAccel
(g's)
Ntf
Ncf
Nte
Nce
Extensio
nNeckMoment(N-m)
Flexion
NeckMoment(N-m)
CompressionNeckLoad(N)
Tens
ionNeckLoad(N)
V
(m/s)
AverageAcceleration(g's)
Test
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
16/27
Results - Baseline
ATD did not
experiencemaximumacceleration
until after 35milliseconds
TestConditions: Baseline
Test #4
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
17/27
Results - Pulse Shape
No condition where IARVs were exceeded
On average the constant-g measured valuesexceeded that of the early-g and late-g pulses
The average initial velocity of the constant-g pulse
was also 1 m/s higher that the early-g pulse and2.5 m/s higher that the late-g pulse
The addition of the HANS device reduced the
tension neck load in every test
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
18/27
Results Pulse Shape
4394373452670.3310.0940.40.387-52.7842.29-509.5159012.514.5Late High-g HANS #2
1485354437660.2820.0930.4090.433-54.9647.49-516.8137012.517.7Late High-g HANS #1
353149240540.42500.1730.195-22.8122.86-461.3264111.212.9Late High-g #2
484273449550.53400.3240.245-31.7415.58-505.2329712.116.6Late High-g #1
3581321423620.250.1520.3150.695-65.2648.18-870.6137012.517.5Constant-g HANS#2
4614364587630.39800.3280.608-57.5238.29-1184206612.518.2Constant-g HANS#1
4877306557550.61400.5040.691-73.3825.16-1011363112.516.8Constant-g #2
3866281450520.53500.4260.651-71.1219.88-950.3324012.517.7Constant-g #1
4043312507680.5050.1170.477NA-41.6771.23-270.9187612.117.6Early High-g HANS #2
2342258400750.43300.3280.469-55.6464.29-710.4186211.215.8Early High-g HANS #1
1821249420740.58200.4810.344-45.9441.42-814.6311511.615.6Early High-g #2
2256251421780.53500.4260.651-44.7729.91-927.8313111.616.9Early High-g #1
1000070010001111-135310-40004170IARV
AxialFemur
Load(N)
HIC15
HIC36
PeakResult
antHead
Acc
el(g's)
NtfNcfNteNce
Extension
Neck
Moment(N-m)
FlexionNeck
Moment
(N-m)
CompressionNeck
Lo
ad(N)
TensionNe
ckLoad
(N)
V(m
/s)
AverageAcc
eleration
(g's)
Test
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
19/27
Results Pulse Shape
V(
m/s)
Average
Acceleration(g's)
AxialFem
urLoad
(N
)
HIC
15
HIC
36
PeakRe
sultant
HeadAc
cel(g's)
NtfNcfNteNce
ExtensionNeck
Momen
t(N-m)
FlexionNeck
Momen
t(N-m)
Compr
ession
NeckLoad(N)
TensionNeck
Load
(N)
Test
602%72%29%22%-36%-63%86%98%134%6%-50%8%9.2%Late High-g
-6%17%0%17%-44%--31%-3%-15%92%5%-50%0%3.5%Constant-g
57%14%8%-6%-16%--11%-6%7%90%-44%-40%0%2.8%Early High-g
Comparison with and w/o HANS
2940363444670.3070.0940.4050.41-53.944.9-513148012.516.1Late High-g Hans Avg
4098342505630.3240.0760.3220.652-61.443.2-1027171812.517.9Constant-g Hans Avg
3193285453710.4690.0590.4030.469-48.767.8-491186911.616.7Early High-g Hans Avg
Average Values w/ HANS
419211344540.4800.2490.22-27.319.2-483296911.614.8Late High-g Avg
4372294504540.57500.4650.671-72.322.5-981343612.517.3Constant-g Avg
2039250420760.55900.4540.498-45.435.7-871312311.616.3Early High-g Avg
Average Values w/o HANS
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
20/27
Results Critical Speed
During the critical late high-g test the tension neck load,
HIC15, HIC36, and femur load IARV were exceeded The use of the HANS device reduced the tension neck load
below the IARV
The use of the HANS did not affect the HIC15, HIC36, and
femur load values AxialFemurLoad(N)
HIC15
HIC36
PeakResultantHead
Accel(g's)
NtfNcfNteNce
ExtensionNeck
Moment(N-m)
FlexionNeckMoment
(N-m)
CompressionNeck
Load(N)
TensionNeckLoad
(N)
V(m/s)
AverageAcceleration
(g's)
Test
1349010421412960.4180.1030.3510.491-45.4240.4-1421230515.620.0Critical Late High-g HANS
13550114315491010.8130.0750.7020.589-58.6957.92-1150481715.620.0Critical Late High-g
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
21/27
Results Critical Speed Kite
Graph (no HANS)
Test Conditions
15.6 m/s
20 g avg 80 ms
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
22/27
Results Critical Speed Kite
Graph (w/ HANS)
Test Conditions
15.6 m/s
20 g avg 80 ms
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
23/27
Conclusions
The baseline tests that approximated the Formula
SAE rules (7.0 m/s, 20-g average deceleration)resulted in measured injury values that were negligiblecompared to the IARV
The tests comparing pulse shape all resulted in values
which were less than the IARV The statistically highest values comparing pulse shape
were seen during the constant-g test however, theaverage acceleration was slightly higher for thesetests
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
24/27
Conclusions Cont.
The addition of a HANS device reduced thetension neck load in every test and brought thetest value below the IARV for the critical speed
test
An impact from 15.6 m/s with a 20-g averagedeceleration rate was found to pose a seriousrisk of injury to the driver, with and without theHANS device.
To reduce the risk of injury to the driver,horizontall mounted tubes should be laced a
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
25/27
Acknowledgements
Janet Brelin-Fornari, John Young and the Kettering
University Crash Safety Center for the use of theirfacility.
Denton Safety Systems for the use of their
equipment Jamie Jones and Red Horse Racing for the donation
of a HANS device for testing.
Lynn St. James and HANS for the donation of twonew HANS devices.
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
26/27
References Gideon, T., Melvin, J., Streetz, L., and Willhite, S. ATD Neck Tension
Comparisons for Various Sled Pulses, Society of Automotive
Engineers, 2002, SAE 2002-01-3324. Society of Automotive Engineers. 2006 Formula SAE Rules.
http://students.sae.org/competitions/formulaseries/
Eppinger R., Sun E., Bandak F., Haffner M., Khaewpong N., MalteseM., Kuppa S., Nguyen T., Takhounts E., Tannous R., Zhang A., Saul
R. Development of Improved Injury Criteria for the Assessment ofAdvanced Automotive Restraint Systems II. November, 1999, TheNational Highway Traffic Safety Administration.
FMVSS 208. May 27, 1998 The National Highway Traffic SafetyAdministration, DOT.
Trauma.org. Abbreviated Injury Scale. Accessed on August 22, 2006.
http://www.trauma.org/scores/ais.html.
8/11/2019 Analysis of a Frontal Impact of a Formula SAE Vehicle
27/27
Thank You For Your Time
Any Questions?