Flex-GT Certification Tests

NHTSA Vehicle Research & Test Center

Flex-TEG MeetingMarch 31, 2008

akonosuTEG-064

Overview

• Fabricated test rig– Slight differences from recommended setup

• Conducted 21 tests– Pre & post vehicle test– Analyzed various configurations

• Spacer vs. no spacer• Ballast vs. no ballast• Nylon vs. steel pivot bolt• Physical vs. software offset• Release method

Test Setup

Setup Differences

Total padding supplied was 31 mm instead of 25 mm Supported rig

with sandbags instead of bolting it down

Wall thickness is 6.25 mm instead of 4.5 mm

We cut this thin wire to release the leg.

Effect of 3 mm Spacer & Ballast

• Presence of spacer and ballast did not affect leg measurements at all

Effect of Pivot Bolt Material• Adjustments to bolt improved pre-impact signal

– Nylon and electrical tape wrap both reduced the magnitude of pre-impact oscillations

-0.5 0 0.5 1 1.5 2Time (sec)

-75

-50

-25

0

25

50

75

100

Tibi

a A

3 M

omen

t (N

- m)

Standard Bolt

Electrical Tape

Electrical Tape w\O-Rings

Nylon bolt

-0.2 -0.15 -0.1 -0.05 0 0.05 0.1Time (sec)

-5

-4

-3

-2

-1

0

1

2

3

4

5

Tibi

a A

3 M

ome n

t (N

-m)

Standard Bolt

Electrical Tape

Electrical Tape w\O-Rings

Nylon bolt

Offset Removal & Release Method

• Pre-impact offset can be done by post-processing the data rather than physically removing it

• Our release method is consistent

-1 -0.5 0 0.5 1 1.5 2Time (sec)

-75

-50

-25

0

25

50

75

100

Tibi

a A

3 M

omen

t (N

- m)

Cert20

Cert21

Cert22

Release

CERTIFICATION DATA

Test Record

Femur A1

135140145150155160165170175180185

Cer

t01

Cer

t02

Cer

t03

Cer

t04

Cer

t05

Cer

t06

Cer

t07

Cer

t08

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t09

Cer

t10

Cer

t11

Cer

t12

Cer

t14

Cer

t15

Cer

t16

Cer

t17

Cer

t18

Cer

t19

Cer

t20

Cer

t21

Cer

t22

Test

Fem

ur1

Mom

ent (

N-m

)

AVG 158.7SD 4.4CV 2.8%

Femur A2

110115120125130135140145150155160

Cer

t01

Cer

t02

Cer

t03

Cer

t04

Cer

t05

Cer

t06

Cer

t07

Cer

t08

Cer

t09

Cer

t10

Cer

t11

Cer

t12

Cer

t14

Cer

t15

Cer

t16

Cer

t17

Cer

t18

Cer

t19

Cer

t20

Cer

t21

Cer

t22

Test

Fem

ur2

Mom

ent (

N-m

) AVG 129.1SD 6.8CV 5.2%

Femur A3

80

85

90

95

100

105

110

115

120C

ert0

1C

ert0

2C

ert0

3C

ert0

4C

ert0

5C

ert0

6C

ert0

7C

ert0

8C

ert0

9C

ert1

0C

ert1

1C

ert1

2C

ert1

4C

ert1

5C

ert1

6C

ert1

7C

ert1

8C

ert1

9C

ert2

0C

ert2

1C

ert2

2

Test

Fem

ur3

Mom

ent (

N-m

)

AVG 98.9SD 7.7CV 7.8%

Tibia A1

120125130135140145150155160165170C

ert0

1C

ert0

2C

ert0

3C

ert0

4C

ert0

5C

ert0

6C

ert0

7C

ert0

8C

ert0

9C

ert1

0C

ert1

1C

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ert1

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ert1

5C

ert1

6C

ert1

7C

ert1

8C

ert1

9C

ert2

0C

ert2

1C

ert2

2

Test

Tibi

a1 M

omen

t (N

-m)

AVG 147.0SD 7.1CV 4.8%

Tibia A2

80859095

100105110115120125130

Cer

t01

Cer

t02

Cer

t03

Cer

t04

Cer

t05

Cer

t06

Cer

t07

Cer

t08

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t09

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t10

Cer

t11

Cer

t12

Cer

t14

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t15

Cer

t16

Cer

t17

Cer

t18

Cer

t19

Cer

t20

Cer

t21

Cer

t22

Test

Tibi

a2 M

omen

t (N

-m)

AVG 116.2SD 3.6CV 3.1%

Tibia A3

50556065707580859095

100C

ert0

1C

ert0

2C

ert0

3C

ert0

4C

ert0

5C

ert0

6C

ert0

7C

ert0

8C

ert0

9C

ert1

0C

ert1

1C

ert1

2C

ert1

4C

ert1

5C

ert1

6C

ert1

7C

ert1

8C

ert1

9C

ert2

0C

ert2

1C

ert2

2

Test

Tibi

a3 M

omen

t (N

-m)

AVG 88.8SD 3.1CV 3.5%

Tibia A4

0

10

20

30

40

50

60C

ert0

1C

ert0

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ert0

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ert0

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ert1

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ert1

8C

ert1

9C

ert2

0C

ert2

1C

ert2

2

Test

Tibi

a4 M

omen

t (N

-m)

AVG 46.7

SD 2.2

CV 4.8%

ACL

0.0

1.0

2.0

3.0

4.0

5.0

6.0C

ert0

1C

ert0

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ert1

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ert1

8C

ert1

9C

ert2

0C

ert2

1C

ert2

2

Test

AC

L El

onga

tion

(mm

)

AVG 4.2SD 0.1CV 3.2%

PCL

0.00.51.01.52.02.53.03.54.04.55.0C

ert0

1C

ert0

2C

ert0

3C

ert0

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ert1

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ert1

9C

ert2

0C

ert2

1C

ert2

2

Test

PCL

Elon

gatio

n (m

m)

AVG 3.9

SD 0.3

CV 7.5%

MCL

10.010.511.011.512.012.513.013.514.014.5

Cer

t01

Cer

t02

Cer

t03

Cer

t04

Cer

t05

Cer

t06

Cer

t07

Cer

t08

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t09

Cer

t10

Cer

t11

Cer

t12

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t14

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t15

Cer

t16

Cer

t17

Cer

t18

Cer

t19

Cer

t20

Cer

t21

Cer

t22

Test

MC

L El

onga

tion

(mm

)

AVG 13.5SD 0.3CV 1.9%

Summary• Certification test does not seem to be sensitive

to any of the following:– Rig connection/support– Impact plate width– Release method– Offset method

• Isolation of leg from rig seems to help reduce noise in moment signals

• Certification data was very repeatable, but did not always fall within the provided corridors

Flex-GT Certification TestsOverviewTest SetupSetup DifferencesEffect of 3 mm Spacer & BallastEffect of Pivot Bolt MaterialOffset Removal & Release MethodTest RecordFemur A1Femur A2Femur A3Tibia A1Tibia A2Tibia A3Tibia A4ACLPCLMCLSummary