Liquid Viscosity Sensing Using Nonlinear Higher Order Harmonic Excitation in Fiberoptic Vibrating Sensor

  • Wei-Chih WangEmail author
  • Per G. Reinhall
Conference paper
Part of the Lecture Notes in Electrical Engineering book series (LNEE, volume 306)


In practice, the vibration amplitudes are always kept sufficiently small in order to avoid nonlinear vibration effects. In this paper, however, nonlinear vibration is intentionally excited to improve the sensitivity of viscosity measurements, in particular nonlinear higher order harmonic excitation. The results show that a nonlinear effect drastically improves sensitivity to viscous damping. Theory and experimental results are presented. Three different experiments were conducted: (1) observe the frequency responses of the third harmonic in a linear system; (2) excite the system into a nonlinear region using different driving (~2 kHz) and response frequencies (~6 kHz); (3) excite the system into a nonlinear region using the same frequency for both driving and response (~6 kHz). For liquid viscosity measurement, the gain per unit of viscosity for the superharmonic case is highest among all cases at 3 dB/cp.


Nonlinear Vibration Viscosity measurement Higher order harmonic excitation Superharmonic excitation Subharmonic excitation Fiber optic sensor Forward light scattering Nonlinear system 


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Copyright information

© Springer International Publishing Switzerland 2014

Authors and Affiliations

  1. 1.Department of Mechanical EngineeringUniversity of WashingtonSeattleUSA
  2. 2.Department of Electrical EngineeringUniversity of WashingtonSeattleUSA
  3. 3.Medical Device Innovation CenterNational Cheng Kung UniversityTainanTaiwan, ROC

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