The effect of hydrostatic pressure fields on the structural and acoustic response of cylindrical shells

Abstract

The effects of external hydrostatic pressure fields and fluid loading on the structural and acoustic response of a point-driven infinitely long circular cylindrical shell were examined over a range of frequencies. The external pressure field was modeled using static prestress terms in the shell equations of motion, and the structural response was characterized by the driving point admittance and the circumferential resonant frequencies. The acoustic response was quantified through calculation of the radiated sound power, both in an overall sense and on an individual modal basis. The analysis was performed for the in-air case as well as for the in-water case. The structural response was found to be strongly affected by fluid and pressure, resulting in significant resonant frequency shifts. However, the overall acoustic response was shown to be nearly independent of the external pressure field, both in air and in water. In addition, it was shown that relatively fewer modes contribute significantly to the sound radiation for the submerged shell as compared to the shell in air. In both cases, the sound generation was controlled by the low-order nonresonant modes.

The effect of hydrostatic pressure fields on the dispersion characteristics of fluid-shell coupled system

“…These stresses are assumed to exist prior to an independent dynamic stresses arising from vibration (Keltie, 1983). …”

“…The presence of a static prestress caused by hydrostatic pressure modifies structural response characteristics. These include the natural frequencies of vibration (Zhang et al, 2004) and the acoustic response (Keltie, 1983).…”

“…The effects of initial deformation and the viscosity parameter of fluid on the propagation characteristics were discussed. The effect of hydrostatic pressure fields on the structure and acoustic response of cylindrical shells immersed in water have been examined in the literature (Keltie, 1983).…”

Acoustic Resonance Scattering by Submerged Elastic Shells

“…(") (pi/p 2 )^2a 2 Di(v) -ix sin aA-M(90) J^Wcr-"')', (p l /p 2 )i<z 2 a~D l (v) + /x sin a£> 2 M'r ". v J^[ J c ~D(v) e~' " edV '^8 b ' > and the saddle P°i nt is found at « = ^/ 2 -Ec l uation ( 89 > is a high-frequency approximation since x (= ^a) is the "large where we have used Eq (76) to obtain Eq (88b).parameter" needed for the validity of the saddle-point asymp-Normalized (sonar or) backscattering cross section of a small coated cylindrical shell vs k,c for ten values of a, b, and c. Plots 6-9 are for a shell thickness of 1/4 in.…”

Resonance frequencies of a spherical aluminum shell subject to static internal pressure

“…Although the maximum ICP investigated was less than 0.5 psi, this result is consistent with the predictions of early theoretical studies of thin cylindrical shells subject to much larger pressures. [3][4][5][6][7][8][9][10] In addition to ICP monitoring, this phenomenon has the potential to be exploited as a diagnostic tool for the pressure inside any thin-walled container that should remain sealed, such as an industrial tank containing hazardous waste.…”