Volume 103, Issue 5, May 1998
Index of content:
- TRANSDUCTION 
103(1998); http://dx.doi.org/10.1121/1.422762View Description Hide Description
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 moldingcoated 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.
103(1998); http://dx.doi.org/10.1121/1.422763View Description Hide Description
Three-dimensional wave propagation and probe modeling in a homogeneous, linear elastic,anisotropic half-space is discussed. The probe is modeled by modifying the traction vector at the interface between an isotropic half-space and an anisotropic half-space. The traction vector is obtained by considering a plane wave in the isotropic solid incident upon the interface. The probe can be of any type, angle, frequency, and size. The probe is attached to an anisotropic half-space and the wave propagation problem is solved by means of Fourier transform techniques. Numerical examples illustrate some of the properties of the probe model and wave propagation in anisotropic solids.