UNIQUE TYPE OF PRIMARY HIGH SHOCK CALIBRATION SYSTEM USING ELECTROMAGNETIC EXCITER Gwo-Sheng Peng (on behalf of Mr. Jiun-Kai Chen) Center for Measurement Standards/ Industrial Technology Research Institute Tel: +886-3-5743773 E-mail: [email protected] 30 July 2014 Outline 1. Motivation 2. Calibration methods 3. Measurement setup 4. Preliminary results 5. Conclusions Copyright 2014 ITRI 工業技術研究院 Motivation: additional requests from industry ISO 16063-13 : Rigid body motion ISO 16063-13 : Hopkinson bar NML Low shock : 200~10 000 m/s2 NML High shock Electric connector 500~5 000 m/s2 3C、Cellphone、 GPS 500~15 000 m/s2 Electric component Laptop 15 000~30 000 m/s2 100~200 m/s2 Industrial PC Optical Lens Parking Sensor 500~1 000 m/s2 500~1 000 m/s2 500~1 000 m/s2 500~50 00 m/s2 Motor electric instrument panel 10 000~1 000 000 m/s2 Military Equients Airbag Fire engine impact test Damage test 100 Copyright 2014 ITRI 工業技術研究院 1 000 10 000 100 000 120 000 m/s2 100 000 m/s2 300 000 m/s2 1 000 000 m/s2 Motivation : Fulfill Traceability Chain U : 1.0 % U : 2.1 % to 2.6 % Copyright 2014 ITRI 工業技術研究院 Extend range to 100 000 m/s2 Requests extend to at least 30 000 m/s2 NML- comparative calibration system 1. Calibration capability: 1 000 ~10 000 m/s2 U : 2.1 % to 2.6 % Throttle Air Computer Suck device Range to be extended Steel ball GPIB Vacuum control Scope 2. Transferring standard calibrated by NML Primary Low shock calibration system. Amplifier Air pump Std. Acc. Cal. Acc. Copyright 2014 ITRI 工業技術研究院 Primary shock calibration methods ISO 16063-13 Methods for the calibration of vibration and Shock transducers — Primary shock calibration using laser interferometry Acceleration peak value: 1 000 m/s2 to 100 000 m/s2 Acceleration peak value: 100 m/s2 to 5 000 m/s2 8 10 7 0° 90° 11 PC 1 9 2 6 13 5 4 12 Rigid body motion Copyright 2014 ITRI 工業技術研究院 3 Wave propagation inside a long thin bar - Hopkinson bar Primary low shock calibration system: Rigid body motion Calibration capability : 200 m/s2 to 10 000 m/s2 Uncertainty: 1.0 % 8 10 0° 11 7 90° 1 PC 9 2 6 13 Copyright 2014 ITRI 工業技術研究院 5 4 12 3 1:Shock machine 2: Electromagnetic exciter 3:Airborne hammer 4:Pad 5:Airborne anvil 6:Accelerometer 7:Amplifier 8:Digital waveform recorder 9:Laser 10:Interferometer 11:Light detectors 12:1st seismic block 13:2nd seismic block Electromagnetic Exciter Specification of NML Electromagnetic exciter Input: AC 110/220 V, 1Φ 2W 50/60 Hz Voltage: (0 to 150) V Current: (0 to 10) A Max. output force: 1000 N Comparison of Shock Exciter Type Force Control Cost Comp. air OK Electromagnetic Better Copyright 2014 ITRI 工業技術研究院 Shock acceleration Noise Repeat. Low g High g Higher OK Poor OK Quiet Lower Better OK OK OK Procedures of calibration aa2,max peak au1,max peak Accelerometer t1 t2 Charge amplifier V3,max Anvil Laser interferometer t3 According to ISO 16063-13:2001 Laser Displace interferometer -ment Low pass filter Differen -tiation (Vel.) Accelerometer Low pass filter upeak Acc. Copyright 2014 ITRI 工業技術研究院 Low pass filter Differen -tiation (Acc.) apeak S sh u peak a peak displacement measurement ISO 16063-13:2001 Methods for the calibration of vibration and Shock transducers — Primary shock calibration using laser interferometry practically ideally u1 : 1+cosφ u2 : 1+cos(π/2+φ) Lissajous figure Copyright 2014 ITRI 工業技術研究院 Data processing for displacements Interferometer signals : Vx h a cos( ) Vy k b cos( ) Elliptical parameters are obtained by least squares fitting and then displacements are calculated. ref: Chien-ming Wu, et al., Correction of nonlinearity in one-frequency optical interferometry, Meas. Sci. Technol. 7 (1996) 520–524 Copyright 2014 ITRI 工業技術研究院 Primary high shock calibration system: Hopkinson-bar Copyright 2014 ITRI 工業技術研究院 30 July 2014 Main components of high shock calibration system Interferometer 0° Copyright 2014 ITRI 工業技術研究院 90° Shock machine Voltage (V) Preliminary results Peak=54.9 V @ 0.161ms Velocity (m/s) Signal from Acc. Time Time (s) (s) Vel.: 0.567967 m/s @ 0.161 ms 0.618869 m/s @ 0.162 ms Acc= 50863 m/s2 Time (s) Signal from interferometer Copyright 2014 ITRI 工業技術研究院 Sen.=1.079 mV/(m/s2) Preliminary results 1st 2nd 3rd 4th 5th 6th Avg. Std. 54.9 55.6 55 55.15 55.46 54.97 55.18 0.29 (0.5%) Peak value from laser 50862 50762 50805 50788 50825 50838 50813 interferometer (m/s2) 35.9 (0.07%) Sensitivity from electromagnetic exciter (mV/(m/s2)) 0.0062 (0.6%) Peak value from accelerometer (V) Sensitivity calibrated by PTB (mV/(m/s2)) Copyright 2014 ITRI 工業技術研究院 1.079 1.095 1.083 1.086 1.091 1.081 1.086 1.112 Conclusions 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. Copyright 2014 ITRI 工業技術研究院
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