30 July 2014

Gwo-Sheng Peng (on behalf of Mr. Jiun-Kai Chen)

Center for Measurement Standards/ Industrial Technology Research Institute Tel: +886-3-5743773

E-mail: Gwo-Sheng.Peng@itri.org.tw

UNIQUE TYPE OF PRIMARY HIGH SHOCK CALIBRATION SYSTEM USING ELECTROMAGNETIC EXCITER

Copyright 2014 ITRI 工業技術研究院

OutlineOutline

1. Motivation

2. Calibration methods

3. Measurement setup

4. Preliminary results

5. Conclusions

Copyright 2014 ITRI 工業技術研究院

Motivation: Motivation: additional requests from industryadditional requests from industry

100 1 000 10 000 100 000 1 000 000 m/s2

NML Low shock : 200~10 000 m/s2

500~5 000 m/s2

15 000~30 000 m/s2Electric component

100~200 m/s2Laptop

Electric connector

500~15 000 m/s23C 、 Cellphone 、GPS

500~1 000 m/s2Industrial PC

500~50 00 m/s2Motor electric instrument panel

500~1 000 m/s2Optical Lens500~1 000 m/s2Parking Sensor

120 000 m/s2Airbag

100 000 m/s2Fire engine impact test

300 000 m/s2Damage test

ISO 16063-13 : Rigid body motion

ISO 16063-13 : Hopkinson bar

NML High shock

10 000~1 000 000 m/s2

Military Equients

Copyright 2014 ITRI 工業技術研究院

Motivation : Fulfill Traceability Motivation : Fulfill Traceability ChainChain

Extend range to 100 000 m/s2

Requests extend to at least 30 000 m/s2

U : 2.1 % to 2.6 %

U : 1.0 %

Copyright 2014 ITRI 工業技術研究院

1. Calibration capability: 1 000 ~10 000 m/s2

U : 2.1 % to 2.6 %

Range to be extended

2. Transferring standard calibrated by NML Primary Low shock calibration system.

Scope

Amplifier

Std. Acc.

Cal. Acc.

Steel ball

Air pump

Air

Throttle

Vacuum control

Suck device

Computer

GPIB

NML- comparative calibration systemNML- comparative calibration system

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ISO 16063-13 ISO 16063-13 Methods for the calibration of vibration and Shock transducers — Primary shock calibration using laser interferometry

Acceleration peak value:100 m/s2 to 5 000 m/s2

Acceleration peak value:1 000 m/s2 to 100 000 m/s2

PC

8

1213

1

2

4 36 5

9

10 0° 90°11 7

Rigid body motionWave propagation inside a long

thin bar - Hopkinson bar

Primary shock calibration methodsPrimary shock calibration methods

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Primary low shock calibration system: Primary low shock calibration system: Rigid body motionRigid body motion

PC

8

1213

1

2

4 36 5

9

10

0° 90°11 7

1:Shock machine 2: Electromagnetic exciter 3:Airborne hammer 4:Pad 5:Airborne anvil 6:Accelerometer 7:Amplifier 8:Digital waveform recorder 9:Laser10:Interferometer11:Light detectors12:1st seismic block13:2nd seismic block

Calibration capability : 200 m/s2 to 10 000 m/s2

Uncertainty: 1.0 %

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TypeForce

ControlCost

Shock accelerationNoise

Repeat. Low g High g

Comp. air

OK Higher OK Poor OK Quiet

Electro-magneti

cBetter Lower Better OK OK OK

Electromagnetic ExciterElectromagnetic Exciter

Specification of NML Electromagnetic exciter

Input: AC 110/220 V, 1Φ 2W 50/60 HzVoltage: (0 to 150) VCurrent: (0 to 10) AMax. output force: 1000 N

Comparison of Shock ExciterComparison of Shock Exciter

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Procedures of calibrationProcedures of calibration

t2

a2,max

t3

V3,maxLaser

interferometerAnvil

Laser interferometer

Accelerometer

Displace-ment

Low passfilter

Differen-tiation(Vel.)

Low passfilter

Differen-tiation(Acc.)

apeak

Acc.Low passfilter

upeak

peak

peaksh a

uS

According to ISO 16063-13:2001

apeak

AccelerometerCharge

amplifier t1

a1,maxupeak

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displacement measurementdisplacement measurement

ideally

u1 : 1+cosφ

u2 : 1+cos(π/2+φ)

ISO 16063-13:2001 Methods for the calibration of vibration and Shock transducers — Primary shock calibration using laser interferometry

Lissajous figure

practically

Copyright 2014 ITRI 工業技術研究院

Interferometer signals :

V h ax cos( )V k by cos( )

ref: Chien-ming Wu, et al., Correction of nonlinearity in one-frequency optical interferometry, Meas. Sci. Technol. 7 (1996) 520–524

Elliptical parameters are obtained by least squares fitting and then displacements are calculated.

Data processing for displacements

Copyright 2014 ITRI 工業技術研究院 30 July 2014

Primary high shock calibration system: Primary high shock calibration system: Hopkinson-barHopkinson-bar

Copyright 2014 ITRI 工業技術研究院

Main components of high shock Main components of high shock calibration systemcalibration system

Interferometer Shock machine

 0° 90°

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Vel

oci

ty

(m/s

)V

olta

ge (

V)

Preliminary results Preliminary results

Peak=54.9 V @ 0.161ms

Vel.:

0.567967 m/s @ 0.161 ms

0.618869 m/s @ 0.162 ms

Acc= 50863 m/s2

Sen.=1.079 mV/(m/s2)

Signal from Acc.Time (s)

Signal from interferometerTime (s)

Vel

oci

ty

(m/s

)

Time (s)Time (s)

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1st 2nd 3rd 4th 5th 6th Avg. Std.

Peak value from accelerometer (V)

54.9 55.6 55 55.15 55.46 54.97 55.180.29

(0.5%)

Peak value from laser interferometer (m/s2)

50862 50762 50805 50788 50825 50838 5081335.9

(0.07%)

Sensitivity from electro-magnetic exciter(mV/(m/s2))

1.079 1.095 1.083 1.086 1.091 1.081 1.0860.0062(0.6%)

Sensitivity calibrated by PTB(mV/(m/s2))

1.112

Preliminary results Preliminary results

Copyright 2014 ITRI 工業技術研究院

1. A unique compact electromagnetic exciter was built to produce stable shock force for low and high shock calibration systems.

2. Installation and operation of the electromagnetic exciter are simple, automatic operation of the calibration system will later be implemented.

3. Need to complete the uncertainty evaluation and check the system performance with PTB calibrated value.

ConclusionsConclusions