Bifurcation Buckling Analysis of Conical Roof Shell Subjected to Dynamic Internal Pressure by the Finite Element Method

2003 ◽  
Vol 125 (1) ◽  
pp. 78-84
Author(s):  
Seiya Hagihara ◽  
Noriyuki Miyazaki
Keyword(s):  
Internal Pressure ◽  
Dynamic Pressure ◽  
Logarithmic Scale ◽  
Pressure Loading ◽  
Oil Storage ◽  
Bifurcation Buckling ◽  
Step Loading ◽  
Accident Conditions ◽  
Roof Shells ◽  
Dynamic Bifurcation

Cylindrical tanks with conical roof shells are utilized as oil storage tanks and for some containment vessels. It is known that conical roof shells and torispherical shells subjected to static internal pressure buckle into a displaced shape with circumferential waves caused by an instability condition commonly called bifurcation buckling. It can be important to obtain the dynamic bifurcation buckling load in designing conical roof shells. In this paper, the bifurcation buckling pressure is calculated for dynamic pressure during accident conditions as characterized by step pressure loading, ramp pressure loading and pulse pressure loading. The minimum bifurcation buckling pressure is shown to be a linear function of radius-to-thickness ratio R/h of the shell in a linear fashion on a logarithmic scale. The minimum bifurcation buckling pressure is minimum for conical roof shells subjected to the step loading. The minimum dynamic bifurcation buckling pressure for step loading is about half of the static bifurcation buckling pressure.

Analysis of Aeroacoustic Phenomena in Centrifugal Compressors Using a Lattice Boltzmann Flow Simulation Approach

2020 ◽  
Author(s):  
Rahul Phogat ◽  
Néstor González Díez ◽  
Jan Smeulers ◽  
Damiano Casalino ◽  
Francesco Avallone
Keyword(s):  
Lattice Boltzmann ◽  
Acoustic Waves ◽  
Dynamic Pressure ◽  
Flow Simulation ◽  
Acoustic Mode ◽  
Secondary Flows ◽  
Pressure Loading ◽  
Compressor Cascade ◽  
High Fatigue ◽  
Return Channel

Abstract Impeller rotation, vortex shedding, secondary flows or a combination of these phenomena can lead to the generation of acoustic waves in the compressor cascade causing dynamic pressure loading on the impeller. When the eigenfrequency and eigenmode shape of the acoustic mode match with the structural ones of the impeller, high fatigue stresses and vibrations occur, which can lead to structural failure. It is well known that cavities enclosing shrouded impellers may strongly amplify the acoustic excitation of the impeller by means of Tyler-Sofrin modes; however, little knowledge is available about the physics of flow-induced noise and resonance mechanisms. In this research, a Lattice Boltzmann Method based approach is employed to predict the origin and amplitude of pressure loading responsible for the strong impeller trailing edge vibrations measured in experiments. The results reveal that this is caused by the acoustic mode generated from the interaction of upstream vane wakes with the impeller that is reflected by the return channel vanes. This research highlights the importance of accounting for aeroacoustic mechanisms in the design of centrifugal compressor stages and paves the way towards the numerical assessment of unsteady flow and resonance phenomena.

Elastic and elastic-plastic finite element analysis of hollow tubes with axisymmetric internal projections under combined axial and pressure loading

2001 ◽  
Vol 36 (4) ◽  
pp. 373-390 ◽  
Author(s):  
S. J Hardy ◽  
M. K Pipelzadeh ◽  
A. R Gowhari-Anaraki
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Internal Pressure ◽  
Plastic Material ◽  
Axial Loading ◽  
Material Model ◽  
Pressure Loading ◽  
Element Analysis ◽  
Elastic Plastic ◽  
Applied Loading

This paper discusses the behaviour of hollow tubes with axisymmetric internal projections subjected to combined axial and internal pressure loading. Predictions from an extensive elastic and elastic-plastic finite element analysis are presented for a typical geometry and a range of loading combinations, using a simplified bilinear elastic-perfectly plastic material model. The axial loading case, previously analysed, is extended to cover the additional effect of internal pressure. All the predicted stress and strain data are found to depend on the applied loading conditions. The results are normalized with respect to material properties and can therefore be applied to geometrically similar components made from other materials, which can be represented by the same material models.

Approximate Elastic Stresses in Pipe Junctions with Chamfer Corners

1981 ◽  
Vol 103 (1) ◽  
pp. 107-111
Author(s):  
D. P. Updike
Keyword(s):  
Internal Pressure ◽  
Stress Analysis ◽  
Elastic Stress ◽  
Branch Pipe ◽  
Optimum Size ◽  
Pressure Loading ◽  
Elastic Stresses ◽  
Rapid Calculation ◽  
Identical Diameter

Elastic stress analysis of a right angle tee branch pipe connection of two pipes of identical diameter and thickness connected through 45-deg chamfer corner sections is developed for internal pressure loading. Stresses in the crotch portion of the vessel are determined. These results are presented in the form of a table of factors useful for rapid calculation of approximate values of the peak stresses. The existence of a structurally optimum size of chamfer is demonstrated.

Mechanism Study on the Coiled Tubing Deformation under a Combination Loading

2011 ◽  
Vol 328-330 ◽  
pp. 1528-1532 ◽  
Author(s):  
Lei Li ◽  
Zhao Xi Shen ◽  
Peng Wang
Keyword(s):  
Internal Pressure ◽  
Deformation Behavior ◽  
Fatigue Tests ◽  
Deformation Mechanisms ◽  
Pressure Loading ◽  
Mechanism Study ◽  
Cyclic Bending ◽  
Coiled Tubing ◽  
Combination Loading

The tendency for coiled tubing to grow in diameter and thin in wall under a combination loading of internal pressure and cyclic bending. This can occur in spite of the fact that nominal stresses due to internal pressure loading are well within elastic limits in both hoop and radial directions. The deformation mechanisms are described. Fatigue tests of 10 coiled tubing specimens are finished. The results show that the trends in coiled tubing deformation behavior are according with the context of theory.

Limit and Burst Pressures for a Cylindrical Vessel With a 30 deg—Lateral d/D⩾0.5

2005 ◽  
Vol 127 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Z. F. Sang ◽  
Y. J. Lin ◽  
L. P. Xue ◽  
G. E. O. Widera
Keyword(s):  
Internal Pressure ◽  
Design Method ◽  
Limit Load ◽  
Diameter Ratio ◽  
Cylindrical Vessel ◽  
Pressure Loading ◽  
Element Analysis ◽  
Design Guideline ◽  
Burst Test ◽  
The Finite Element Analysis

The purpose of this paper is to provide research results for a cylindrical vessel—30 deg lateral intersection with diameter ratio d/D⩾0.5 under increasing internal pressure loading. The results include those from tests as well as from an inelastic stress analysis. The experimentally determined limit load is compared with that from the finite element analysis. The stress concentration factor, the spread of the plastic area, and the behavior of the deformation are provided. Also, a burst test of the model vessel is carried out to provide some data to justify the existing design method and forms a basis for developing an advanced design guideline for cylindrical vessel—lateral intersection under internal pressure loading.

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