Low‐frequency acoustic scattering from finite cylindrical shells immersed in water. New resonances related to the shell length

1990 ◽  
Vol 88 (2) ◽  
pp. 1184-1185
Author(s):  
Florence Lecroq
Keyword(s):  
Shell Length ◽  
Cylindrical Shells ◽  
Acoustic Scattering ◽  
Low Frequency

Modified Svensson’s Formula for More Accurate Burst Pressure Predictions of Thin Cylindrical Shells With Small Shell Length to Diameter Ratios

2015 ◽  
Author(s):  
Sang-Guk Kang ◽  
Kuao-John Young
Keyword(s):  
Shell Length ◽  
Safety Management ◽  
Cylindrical Shells ◽  
Burst Pressure ◽  
Process Safety ◽  
Finite Element Analyses ◽  
Improved Method ◽  
Displacement Effect ◽  
Study Results ◽  
Small Shell

For process safety management purposes, it is often required in industries to perform burst pressure calculations for pressurized equipment subjected to internal deflagrations. In predictions of burst pressures of vessels with short cylindrical shell sections, the stiffening effects of heads are often overlooked, which may lead to underestimated results. In this paper, a new improved method is proposed for predictions of burst pressures of thin cylindrical shells with small shell length to diameter ratios (L/D) at ambient temperature. The idea is to use the Svensson’s formula, modified by a factor that accounts for the effects of small L/D ratios, head types, and materials for more accurate predictions. Tables of such factors are developed based on study results from a series of elastic-plastic Finite Element Analyses including large displacement effect for different L/D ratios, thicknesses, materials, and head types. Some example problems are presented to validate the method.

Acoustic Scattering from Bi-Layered Cylindrical Shells: Influence of the Layers Thicknesses on the Guided Waves

2019 ◽  
Vol 105 (6) ◽  
pp. 1251-1257
Author(s):  
Younes Khandouch ◽  
El Houcein Aassif ◽  
Said Agounad
Keyword(s):  
Stainless Steel ◽  
Guided Waves ◽  
Shape Change ◽  
Cylindrical Shells ◽  
Acoustic Scattering ◽  
Modal Identification ◽  
Current Work ◽  
Geometrical Characteristics ◽  
Cutoff Frequencies

The current work focuses on the study of acoustic scattering from bi-layered stainless steel-copper and copper-stainless steel cylindrical shells filled with air and immersed in water. This paper is interested in revealing the effects of physical and geometrical characteristics of the layers constituting the shells on the scattering phenomenon. The object of this work, is to study the influence of the layers thicknesses on guided waves, the overall thickness of the shells is fixed. The plane of modal identification was chosen to analyze the scattering phenomenon. We investigate the resonance trajectories of the guided waves, especially the curves change. The investigation and comparison made on resonance trajectories, show a shape change, a gradual deviation, or both, appear on the resonance trajectories of different guided waves, for the reduced cutoff frequencies of guided waves a sliding to higher and lower value are noticed. The interaction between guided waves is also manifested in the scattering phenomenon. The findings for the bi-layered cylindrical shells are then compared with those obtained for the mono-layered stainless steel and copper cylindrical shells. Then, this work is completed by an investigation on the reduced cut-off frequencies of the A1 wave, that have been extracted for different possible values of the intermediary radius. In this part, to understand the observed phenomena, other examples of bi-layered cylindrical shells are introduced. The obtained results are analyzed and investigated.

Sign in / Sign up

Export Citation Format

Share Document