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
This is a preview of subscription content, log in to check access.
Wang W-C, Reinhall P, Yee S (1999) Fluid viscosity measurement using forward light scattering. Meas Sci Technol 10:316–322CrossRefGoogle Scholar
Wang W-C, Yee S, Reinhall P (1995) Optical viscosity sensor using forward light scattering. Sens Actuators, B 24–25:753–755CrossRefGoogle Scholar
Wang W-C (1996) A study of fluid viscosity and flow measurement using fiber-optic transducer. Ph.D. Thesis, University of Washington, U.S.AGoogle Scholar
Fedorchenko AI, Stachiv I, Ho J, Wang A, Wang W-C (2008) On the forced vibration of the fiber partially immersed in fluid. Sens Actuators, A: Phys 147(2):498–503CrossRefGoogle Scholar
Fedorchenko AI, Stachiv I, Wang AB, Wang W-C (2008) Fundamental frequencies of mechanical systems with N-piecewise constant. J Sound Vib 317:490–495CrossRefGoogle Scholar
Fedorchenko AI, Stachiv I, Wang W-C (2013) Method of the viscosity measurement by means of the vibrating micro-/nanomechanical resonators. Flow Meas Instrum 32:84–89CrossRefGoogle Scholar
Timoshenko S, Young DH, Weaver W Jr (1974) Vibration problems in engineering, 4th edn. Wiley, New YorkGoogle Scholar