A finite element analysis of an interferometric optical fiber hydrophone

Abstract

This paper investigates the influence of structural parameters on the performance of an optical fiber wound mandrel hydrophone by using the finite element method (FEM). A hydrophone should exhibit the highest possible sensitivity, the widest possible flat frequency response, and an omni-directional sensitivity pattern within the frequency range. The parameters studied included the mandrel geometry, the thickness of the molding coated over the fiber, and the material properties of the constituent parts of the hydrophone. The analysis results showed that the pressure sensitivity of a hydrophone increases in relation to the length of the mandrel and the thickness of the molding. A higher pressure-sensitivity also requires a mandrel or molding material with a relatively low Young’s modulus and Poisson’s ratio. On the other hand, the flat frequency response of a hydrophone increases when either the mandrel length is shortened or the mandrel material is hardened. The omni-directional characteristic is also improved with a shorter mandrel. Therefore, a hydrophone with the best performance must balance the tradeoff between the geometrical and material parameters. The analysis discussion is focused on a representative specification of a frequency range of up to 5 kHz.

Characteristic frequency analysis of valve internal leakage detection based on fiber optic acoustic wave sensor

“…To meet the requirement of the characteristic frequency range of the simulated valve internal leakage acoustic signals mentioned above, it is necessary to increase the resonant frequency of the sensor to avoid resonance [8] , which is related to the material and structure of the sensor itself [9] . In this study, we employ a core-cladding fiber optic acoustic sensor designed by our research group [10] .…”

Crack Propagation Calculations for Optical Fibers under Static Bending and Tensile Loads Using Continuum Damage Mechanics

“…In this work, the finite element model is generated in ANSYS Workbench to obtain the mechanics parameters, including strain and stress, that will be used in the calculation of damage of interested elements. Here, we use the three-dimensional optical fiber winding model in hydrophone [ 33 ] with a change of the geometry parameters and a simplification of the twining mode. As shown in Figure 2 , spiral optical fibers wound on the spool are simplified as a length of fiber circumferentially twined on a part of the spool.…”

“…The Young’s modulus of the inner coating is 3.5 MPa, and that of the outer coating is 6.24 GPa. The other geometry parameters as well as the material properties of the optical fiber in the simulation are listed in [ 33 ].…”

Characterization of the spatio-temporal response of optical fiber sensors to incident spherical waves

“…3,19 These investigations were based on scattering models describing the scattering and transmission of plane acoustic waves by a homogeneous, solid cylinder, i.e., investigating uncoated glass fibers only. Although later works also applied the finite element method to elaborate the influence of elastic and geometric parameters of coated fibers in the frequency response, 20 the geometrical simplicity of the problem with a cylindrical cross-section allows a straightforward extension of the original problem to coated fibers with multiple layers 16,21 by pure analytical models using the transfer matrix method, for example. 22 The main drawback of these previously published models is that they all assume incident plane waves.…”