1. Vibration and Shock in National Institute of Metrology Chenguang CAI Vibration and Gravity Lab

2. Outline
1、Resume 2、Location of NIM 3、Staff of Vibration and Shock Lab in NIM 4、Working tasks 5、Measurement Standards 6、Research under doing 7、Research plan in next five years

3. Resume
Present National Institute of Metrology. Vibration and Shock calibration
Post doctor at Nokia Research Center. Research activities: User interaction sensing
Resistive multi touch screen
Dual-mode loudspeaker
Multi-directivity sound device
3D display by controlling grating
PhD in Precision Instrumentation and Mechanics, Beijing University of Aeronautics and Astronautics.
Research topic: close-loop controlling of resonant sensor
B.Sc. in Automatic Control, Beijing University of Aeronautics and Astronautics.
The sound is modulated by a ultra sonic signal,
High frequency signal attenuates quicker than low frequency signal.

4. NIM —— Locations of Two Campus
40 km

5. NIM —— Gates of Two Campus
There are 13 tombs of emperors of Ming dynasties.

6. NIM —— Hepingli Campus

7. NIM —— Changping Campus

8. New Lab for Vibration and Shock
13m*5.5m*3m
>500 ton

9. Staff of Vibration and Shock Lab
Mechanics and Acoustics Division
Vibration and Gravity Lab
Acoustic Lab
Mass Lab
Force and Torque Lab
Volume and Density Lab
Hardness Lab

10. Staff of Vibration and Shock Lab
Mechanics and Acoustics Division
Vibration and Gravity Lab
Head of the Lab
Dr. CAI Chenguang
Dr. LIU Zhihua
Mr. ZUO Aibing
Mr. LIU Aidong
Mr. YANG Lifeng
Mr. Hu Hongbo
Mr. XIA Yan
Mr. LI Jingshen
Vibration and Shock
8 employees
retire
comparison
Gravity
6 employees
Speed
Dr. SUN Qiao
4 employees
CCAUV Delegate

11. Working tasks Research —— projects and budget from government
Realization and dissemination of motion units
Measuring methods and devices of motion units
Service —— more than 2000 certificates
Calibration of transducers, measuring chains and instruments
Calibration/testing of vibration and shock generators
Measurement of environmental vibration
International Cooperation
BIPM CCAUV
APMP TCAUV
ISO TC108

12. Ultra-low frequency vibration standard (1 m stroke)
Vibration Measurement Standard
Homodyne
Heterodyne
Interferometer
Ultra-low frequency vibration standard (1 m stroke)

13. Low frequency vibration standard (vertical and horizontal)
Vibration Measurement Standard
Fundamental research and hearing aid assessment.
Low frequency vibration standard (vertical and horizontal)

14. Middle frequency vibration standard (SE-09 is used now)
Vibration Measurement Standard
Fundamental research and hearing aid assessment.
Middle frequency vibration standard (SE-09 is used now)

15. High frequency vibration standard (piezoelectric stack)
Vibration Measurement Standard
Fundamental research and hearing aid assessment.
High frequency vibration standard (piezoelectric stack)

16. CS 18 primary vibration calibration system (2911 and APS 113)
Vibration Measurement Standard
Trade
Economy
CS 18 primary vibration calibration system (2911 and APS 113)

17. Low shock standard (electro-magnetic exciter)
Shock Measurement Standard
Fundamental research and hearing aid assessment.
Low shock standard (electro-magnetic exciter)

18. Shock Measurement Standard
Diameter
High shock standard (Hopkins bar excited by air gun and piezoelectric stack)

19. Low Frequency and Middle Frequency (diffraction grating )
Angular Vibration Measurement Standard
Low Frequency and Middle Frequency (diffraction grating )

20. Air bearing 3 axial shaker
3 Component Vibration Measure Standard
Technician
Air bearing 3 axial shaker

21. Frequency response by shock excitation
Pulse width

22. In-situ calibration
The key problem for in-situ calibration of vibration transducer is: Vibration Source!
Solution for calibration purpose vibration source:
Inverse piezoelectricity for accelerometers with exciting piezoelectric component;
Lorentz force for transducers with calibration coil.
The key problem for in-situ calibration of vibration transducer is: Vibration Source!
The transducers cannot be detached from the local spot. How to excite them for calibration purposes?
Solution for calibration purpose vibration source:
For piezoelectric accelerometers, inverse piezoelectricity can be excited by an electric signal to produce inside seismic mass vibration.
For magnetoelectric velocity transducers, Lorentz force can be excited by an electric signal to produce inside seismic mass vibration.

23. Operation Principle for coil type
For vibration transducers with built-in calibration coil, in-situ calibration method had been researched, and an ISO standard ( ) is in process.
The coil is excited by an electric signal to produce electromagnetic force to simulate inertia force to vibrate the pendulum.

24. Calibration Procedure for coil type
E: Output electric signal
Ue: Exciting electric signal
Sv: Sensitivity
S: Electric sensitivity
c: Coefficient of calibration coil
X: Vibration measured
In Lab
In Situ
Calibrated by vibration standard
Calibrated by electric signal
Calculated
Calibrated by electric signal
Calculated

25. In-situ calibration for coil type
The electric sensitivity “S” can be calibrated only by electric signals, it is possible and easy to calibrate in-situ.
Based on S = c Sv, the performance of transducer can be reflected by “S”, it can be used to evaluate the validity and reliability of the transducer, and it is traceable to a vibration standard by “c”.
In practice, manufactures only calibrate “c” in reference point (in static state) using gravity, and “c” is regarded as a constant. It causes big error in high frequency range.

26. Experiments of coil type
X Y Z
The key problem for in-situ calibration of vibration transducer is: Vibration Source!
The transducers cannot be detached from the local spot. How to excite them for calibration purposes?
Solution for calibration purpose vibration source:
For piezoelectric accelerometers, inverse piezoelectricity can be excited by a electric signal to produce inside seismic mass vibration.
For magnetoelectric velocity transducers, Lorentz force can be excited by a electric signal to produce inside seismic mass vibration.
A triaxial transducer with built-in calibration coils was respectively calibrated by NIM low frequency primary vibration standard and calibration coils.

27. Experiments of accelerometers
In Lab
In Lab

28. Seismometer —— a kind of natural standard
USGS NHNM 1×10-6 g
USGS NHNM 1×10-8 g
Intrinsic microseism frequency：3.2 Hz
Magnitude: 0.05 μm/s
Purpose: evaluation of vibration transducer resolution and noise.

29. Low Frequency Calibration Using Machine Vision
Requirements：
1）Wind power generation monitoring
2）Power transmission line monitoring
3）Machine Vision monitoring method
Problems:
1）How to reproduce the big vibration?
2）Laser vibrometer is not suitable for.
3）How to calibrate the cameras?
Idea：A new trace methold
1）Virtual motion produced by a display.
2）Camera is calibrated by virtual motion.
3）Camera can be a transfer standard.
4）Rotary table is a choice for 1 g low frequency calibration.

30. Research plan in next five years
National Quality Infrastructure (NQI)
1. Machine Vision based low frequency vibration calibration
2. 1 g low frequency vibration calibration by using rotary table
3. Angular rate and rectilinear acceleration calibration by a rotary table (centrifuge)
Other
Shock
1. Response of accelerometers by step excitation
Vibration
1. Angular vibration calibration
2. Multi component vibration calibration
3. Impedance head calibration
The concept was published in last APMP meeting in Beijing by the director of NIM.
Jörn Stenger of PTB gave a presentation “Metrology and Industrie 4.0” .
AQSIQ （General Administration of Quality Supervision, Inspection and Quarantine）
APMP（Asia Pacific Metrology Programme）

31. Acoustic lab
Noise measurement for standard power source, automobile, some electrical appliance.

32. Acoustic lab
Fundamental research and hearing aid assessment.

33. Welcome to visit NIM! Phone: +86 10 64524622, Mobile: +86 13511028631
Don't hesitate, please contact me.
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