Stability of Ring-Stiffened Tubular Members Under External Pressure

1995 ◽  
Vol 117 (2) ◽  
pp. 150-155 ◽  
Author(s):  
S. A. Karamanos ◽  
J. L. Tassoulas
Keyword(s):  
Experimental Data ◽  
Finite Element ◽  
Stability Analysis ◽  
External Pressure ◽  
Nonlinear Finite Element ◽  
Steel Tubes ◽  
Deformation Plasticity ◽  
The Stability ◽  
Element Technique ◽  
Stiffened Steel

This paper presents results of a rigorous nonlinear finite element technique for the stability analysis of ring-stiffened steel tubes under external pressure. Large deformation, plasticity, as well as residual stresses and imperfections, are taken into account. Both internal and external stiffeners are simulated. A study of various parameters which affect pressure capacity is summarized, along with a comparison with available experimental data.

Finite Element Analysis for the Stiffness and the Buckling of Corrugated Tubes in Heat Exchanger

2012 ◽  
Vol 468-471 ◽  
pp. 1675-1680 ◽  
Author(s):  
Xiao Jing Wang ◽  
Zhi Min Wang ◽  
Nian Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stability Analysis ◽  
Heat Exchanger ◽  
Heat Exchangers ◽  
External Pressure ◽  
Element Analysis ◽  
Value Analysis ◽  
Compressive Pressure ◽  
The Stability

Corrugated tubes in a heat exchanger are analyzed by using the FEA methods. And the formula how to compute single wave’s rigidity is obtained. Besides, methods of analyzing the stability of corrugated tubes under internal compressive pressure and external pressure are proposed which include characteristic value analysis and non-linear stability analysis, thus providing theory basis for the stability research of heat exchangers.

Design and Stability Analysis of Latticed Shell Structure in Site of Tianluoshan

2012 ◽  
Vol 193-194 ◽  
pp. 864-867
Author(s):  
Wen Feng Du ◽  
Zhi Fei Sun
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Stability Analysis ◽  
Shell Structure ◽  
Nonlinear Finite Element ◽  
Nonlinear Finite Element Method ◽  
Geometrical Nonlinear ◽  
The Stability ◽  
Element Method ◽  
Geometrical Nonlinear Finite Element

The design and analysis of the large span steel latticed shell structure in site of Yuyao TianLuoshan is introduced, and some key problems are dwelled on in this paper. By the geometrical nonlinear finite element method, the nonlinear stability analysis is carried out. The buckling modal and the whole course of instability are shown by two analysis method, the eigen-buckling analysis and the geometrical nonlinear finite element method. The influence of spring support to the stability of the structure is analyzed. It is shown that the structure has good wind-resisting capacity, which is fit to the circumstance near sea with lots of typhoon. Large compressive membrane stresses arise in the structure under the condition of temperature rise, leading to a significant reduction in the stability load-carrying capacity of the structure.

Influence of a localized plastic layer on embankment stability

1977 ◽  
Vol 14 (4) ◽  
pp. 524-530 ◽  
Author(s):  
C. D. Thompson ◽  
J. J. Emery
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Clayey Soil ◽  
Plastic Material ◽  
Plastic Layer ◽  
Natural Soil ◽  
General Terms ◽  
Clayey Silt ◽  
The Stability ◽  
Embankment Stability

Conventional stability analyses of a 47 ft (14.3 m) high embankment constructed of clayey silt fill indicated a satisfactory design with 2:1 slopes. However, cracking of the fill and movements of the embankment occurred when its height reached 32 ft (9.8 m). Investigation revealed that, in general terms, the geotechnical profile employed for the stability analysis was satisfactory. There was a localized layer of firm clayey soil at the interface between the fill and natural soil, which coincided with the observed cracks and the zone of high pore pressure.Construction scheduling was critical, and an initial wedge analysis showed that a 17 ft (5.2 m) high berm would ensure adequate safety during completion of the fill. A detailed investigation followed to determine the actual deformation mechanism responsible for the cracking. This included plane strain finite element runs using estimated moduli values. It was concluded that the cracking was caused by ‘spreading’ of plastic material at or near the base of the embankment. This case history illustrates that localized layers of weaker soil can be critical even when construction has been carefully controlled.

Stability and Response of Rotors Supported on Active Magnetic Bearings

1993 ◽  
Author(s):  
K. Ramesh ◽  
R. G. Kirk
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Transfer Matrix ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Finite Element Program ◽  
Element Program ◽  
Matrix Codes ◽  
The Stability

Abstract A PC-based program has been developed which is capable of performing stability analysis and response calculations of rotor-bearing systems. The paper discusses the modeling of rotors supported on active magnetic bearings (AMB) and highlights the advantages in the modeling using the finite element method, over the transfer matrix method. An 8-stage centrifugal compressor supported on AMB was chosen for the case study. The results for the stability analysis, obtained using the finite element program was compared with those obtained by the well established transfer matrix codes. The results of unbalance response, including the effects of sensor non collocation are presented and this demonstrates how an AMB supported rotor can experience a synchronous instability for selected sensor locations and balance distributions.

scholarly journals Theoretical stability analysis of mixed finite element model of shale-gas flow with geomechanical effect

2020 ◽  
Vol 75 ◽  
pp. 33
Author(s):  
Mohamed F. El-Amin ◽  
Jisheng Kou ◽  
Shuyu Sun
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Shale Gas ◽  
Gas Flow ◽  
Mixed Finite Element ◽  
Mixed Finite Element Method ◽  
Element Model ◽  
Mathematical Proofs ◽  
The Stability ◽  
Shale Gas Transport

In this work, we introduce a theoretical foundation of the stability analysis of the mixed finite element solution to the problem of shale-gas transport in fractured porous media with geomechanical effects. The differential system was solved numerically by the Mixed Finite Element Method (MFEM). The results include seven lemmas and a theorem with rigorous mathematical proofs. The stability analysis presents the boundedness condition of the MFE solution.

The Solution of Lateral Heat Loss Problem Using Collocation Method with Cubic B-Splines Finite Element

2011 ◽  
Vol 110-116 ◽  
pp. 3184-3190
Author(s):  
Necdet Bildik ◽  
Duygu Dönmez Demir
Keyword(s):  
Finite Element ◽  
Stability Analysis ◽  
Heat Loss ◽  
Collocation Method ◽  
Numerical Solutions ◽  
Analytic Solutions ◽  
B Splines ◽  
Stability Method ◽  
The Stability ◽  
Lateral Heat

This paper deals with the solutions of lateral heat loss equation by using collocation method with cubic B-splines finite elements. The stability analysis of this method is investigated by considering Fourier stability method. The comparison of the numerical solutions obtained by using this method with the analytic solutions is given by the tables and the figure.

Development of Material Constants for Nonlinear Finite-Element Analysis

1988 ◽  
Vol 61 (5) ◽  
pp. 879-891 ◽  
Author(s):  
Robert H. Finney ◽  
Alok Kumar
Keyword(s):  
Experimental Data ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Large Strain ◽  
Strain Range ◽  
Nonlinear Finite Element ◽  
Element Analysis ◽  
Material Models ◽  
Tensile Data

Abstract The determination of the material coefficients for Ogden, Mooney-Rivlin, Peng, and Peng-Landel material models using simple ASTM D 412 tensile data is shown to be a manageable task. The application of the various material models are shown to be subject to the type and level of deformation expected, with Ogden showing the best correlation with experimental data over a large strain range for the three types of strain investigated. At low strains, all of the models showed reasonable correlation.

Theoretical Prediction of Onset of Horizontal Slug Flow

1980 ◽  
Vol 102 (4) ◽  
pp. 441-445 ◽  
Author(s):  
Kaichiro Mishima ◽  
Mamoru Ishii
Keyword(s):  
Experimental Data ◽  
Stability Analysis ◽  
Slug Flow ◽  
Flow Analysis ◽  
Finite Amplitude ◽  
Empirical Correlations ◽  
Deformation Limit ◽  
Theoretical Criterion ◽  
The Stability ◽  
Good Agreement

A criterion for the onset of a slug flow in a horizontal duct is derived theoretically. A potential flow analysis is carried out by considering waves of finite amplitude. The stability criterion is obtained by introducing the wave deformation limit and the “most dangerous wave” concept in the stability analysis. The present theoretical criterion for slug formation shows very good agreement with a large number of experimental data and with some empirical correlations.

DYNAMICS OF SHALLOW CABLES UNDER TURBULENT WIND: A NONLINEAR FINITE ELEMENT APPROACH

2011 ◽  
Vol 11 (04) ◽  
pp. 755-774 ◽  
Author(s):  
NICOLA IMPOLLONIA ◽  
GIUSEPPE RICCIARDI ◽  
FERNANDO SAITTA
Keyword(s):  
Finite Element ◽  
Equilibrium Shape ◽  
Equations Of Motion ◽  
Plane Motion ◽  
Computational Effort ◽  
Nonlinear Finite Element ◽  
Initial Shape ◽  
Linear Behavior ◽  
Element Technique ◽  
Nonlinear Equations Of Motion

In classic cable theory, vibrations are usually analyzed by writing the equations of motion in the neighborhood of the initial equilibrium configuration. Furthermore, a fundamental difference exists between out-of-plane motions, which basically corresponds to the linear behavior of a taut string and in-plane motion, where self-weight determines a sagged initial profile. This work makes use of a continuous approach to establish the initial shape of the cable when it is subjected to wind or fluid flow arbitrarily directed and employed a novel nonlinear finite element technique in order to investigate the dynamics present around the initial equilibrium shape of the cable. Stochastic solutions in the frequency domain are derived for a wind-exposed cable after linearization of the problem. By applying the proper orthogonal decomposition (POD) technique with the aim of reducing computational effort, an approach to simulate modal wind forces is proposed and applied to the nonlinear equations of motion.

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