Fiber Optic Sensors for Smart Structure and Structural Health Monitoring

Transcription

1 Prof. O.B. Vitrik, Fiber Optic Sensors for Smart Structure and Structural Health Monitoring Far Eastern State Technical University, Vladivostok, Russia Institute Automatic and Processing Control, Far Eastern Branch of Russian Academy of Sciences,

2 Contents: Smart structure principles Fiber optic sensors for smart structure and structural health monitoring Principles for fiber optic sensors Principles for fiber optic sensing systems Amplitude and phase fiber optic sensors for the monitoring systems Tomography fiber optic systems for structural monitoring.

3 Smart structure External problem Smart Structure Appropriate solution

4 Smart structure Nervous system Brain (Computer)

5 Key features of fiber optic sensor for smart structure applications: High flexibility Low mass and low diameter. It is possible to insert the optical fiber in many materials Hi sensitivity to number of physical and chemical quantities. Immunity to electromagnetic interference Immunity to corruption Wide range of sensor gauge lengths Ability to distant monitoring The Ability to Multiplex Many Fiber Optic Sensors Possibility to Create Fiber Optic Sensor Network The Ability to 1-D, 1 2-D 2 D and 3-D 3 D areas monitoring Possible Low Cost, High Performance Devices

6 position, deformations, inclinations, strains, forces, pressures, accelerations, Fiber Optic Sensor s s measuring m quantities vibrations, temperatures, humidity, air temperature, wind speed and direction, water levels and flow,

7 Fiber-optics sensors. Intrinsic and extrinsic fiber-optics sensors. Fiber grating sensors. Interferometric fiber-optics sensors Fiber-optics sensors based on light amplitude changing. Nonlinear and other fiber - optics sensors.

8 Extrinsic fiber-optics sensor. Light source Processing system Measuring value Extrinsic light parameters modulator Intrinsic fiber-optics sensors. Light source Measuring value Processing system

9 Fiber grating sensors. Measuring value λ ref = 2Λn ef

10 Interferometric fiber-optics sensors. Ψ external effect Δl Ψ+ΔΨ

11 Amplitude fiber-optics sensors. external effect

12 Nonlinear sensors based on Mandelshtam-Brillouin scattering.

13 Advantages and disadvantages of Different Fiber Optic Sensors. ADVANTAGES DISADVANTAGES Grating Sensor low cost; Sensing of transverse & Expensive signal processing and longitudinal strain, strain interrogation technology gradients, temperature, pressure Problem of temperature and and corrosion strain signal division Interferometer Extremely flexible geometry Problem of multisensing High sensitivity, signal division; Wide area distribution Sensitivity stabilization problem Amplitude Tuning control problem Low cost; Simplicity, In many cases low sensitivity Easy installation, and presence of mobile Possibility of coverage of wide mechanical elements, high area requirements to stability of light Nonlinear source intensity Possibility of distributed sensor fabrication. Low sensitivity, high cost

14 Fiber optic measuring systems: M (x,y,t) M(t) M(L,t) M M(L,t) M(L,t) M L M(L,t) N N-1. i i N L

15 Fiber optic measuring systems: Y X Y M(x,y,t) X Y X Y M(x,y,t) X

16 Integral sensitivity fiber optic sensor S(L) L S(L) dl

17 Tomography system principle

18 Tomography system principle

19 Amplitude tilt sensors

20 Amplitude bending sensors

21 Amplitude sensors OTDR interrogation

22 Amplitude accelerometer

23 Amplitude accelerometer

24 Amplitude hydrophone

25 The threshold FOS for pipeline health monitoring

26 Photo of a place of break of a welded seam of pipeline together with worked threshold FOS

27 External pressure sensing

28 Traditional Phase Fiber-optics sensors based on Mach - Zender scheme. External effect Measuring value Laser Detector (0) I Σ = I1 + I2 + 2I1 I2 cos( ΔΨ01 + kn1l )

29 Single fiber double mode interferometer External effect External effect efect Laser Detector Detector

30 Double mode interference pattern

31 Waveguide processing of DMI signal LP 11 LP 01 LP 01

32 Integral sensitivity long strain sensor

33 Strain and Cracking control in concrete beams 1 2 F F h

34 Strain control in concrete beams Δϕ, рад 2π π F, Н

35 Cracking control in concrete beams

36 Fiber-optics sensors based on single- fiber multimode interferometer scheme. Distributed Optical field detector Corr Calc Linearizator

37 SFMI hydrophone

38 SFMI hydrophone Laser Измеритель гидростатического давления на основе ОМИ 3

39 Beam bending monitoring by SFMI

40 Tomography scanning process

41 Tomography scanning process

42 Tomography scanning process

43 Tomography scanning process

44 Tomography scanning process

45 Tomography scanning process

46 Tomography scanning process

47 Tomography scanning process

48 Fiber optic network of tomography type

49 Software for Scalar field monitoring by OF tomography system

50 Acceleration field monitoring by OF tomography system

51 Acceleration field monitoring by OF tomography system

52 Acceleration field monitoring by OF tomography system

53 Vector field monitoring by OF tomography system h(x,y,φ)= r A( x, r y) e

54 Vector field monitoring by OF tomography system r r h(x,y,φ)=d( A(x, y)e )/dl r g( p, φ) = R[ diva( x, y)]

55 Vector field monitoring by OF tomography system g ( p, φ ) = R[ A ( x, y)] r r h(x,y,φ)= ( A(x, y)e ) 2 2

56 Software for Vector field monitoring by OF tomography system

57 Vector field of longitudinal shifts monitoring by OF tomography system

58 Vector field of longitudinal shifts monitoring by OF tomography system

59 Vector field of longitudinal shifts monitoring by OF tomography system

60 Vector field of transversal shifts gradients monitoring by OF tomography system

61 Vector field of transversal shifts gradients monitoring by OF tomography system

62 Laboratory model for smart skin

63 Problem under solution -Stabilization of sensitivity, -Improving of FO sensors and sensing system adaptivity - Improving of technology for FO sensors and sensing system fabrication - Development of new principles for FO sensors and sensing system based on nanotechnology