NONLINEAR BUCKLING OF MARINE ELASTICA PIPES TRANSPORTING FLUID

2001 ◽  
Vol 01 (03) ◽  
pp. 333-365 ◽  
Author(s):  
S. CHUCHEEPSAKUL ◽  
T. MONPRAPUSSORN
Keyword(s):  
Large Strain ◽  
Slenderness Ratio ◽  
Internal Flow ◽  
Pipe Material ◽  
Postbuckling Behavior ◽  
Limit States ◽  
Nonlinear Buckling ◽  
Critical Weight ◽  
Strain Formulation ◽  
Nonlinear Buckling Analysis

This paper addresses the nonlinear buckling and post-buckling behavior of an extensible marine elastica pipe conveying fluid. The mathematical model employed in the nonlinear buckling analysis is developed based on the extensible elastica theory and the large strain formulation, so that the high extensibility of the pipe due to large axial strains is tackled thoroughly. The boundary value problem of the model is solved by the shooting method, and the numerical elastica solutions are obtained. For stability examination, the method of adjacent nonlinear equilibrium is exploited. It is revealed that the fundamental mode of nonlinear buckling of the pipe is reached when the pipe experiences either the critical top tension or the critical weight. Postbuckling behavior of the pipe is recognized to be unstable. The investigation is extended to studying various parameters that impinge on the limit states of the pipe. These parameters are the dimensionless quantities that relate to density of pipe material, densities of external and internal fluids, applied top tension, Poisson's ratio, slenderness ratio, vessel offset, seawater depth, current-drag coefficients, current velocity, and internal flow velocity.

Nonlinear Postbuckling of Auxetic-Core Sandwich Toroidal Shell Segments with CNT-Reinforced Face Sheets Under External Pressure

2021 ◽  
Author(s):  
Nguyen Van Tien ◽  
Vu Minh Duc ◽  
Vu Hoai Nam ◽  
Nguyen Thi Phuong ◽  
Lanh Si Ho ◽  
...  
Keyword(s):  
Core Layer ◽  
Elastic Interaction ◽  
Radial Pressure ◽  
Equation System ◽  
External Pressure ◽  
Toroidal Shell ◽  
Postbuckling Behavior ◽  
Nonlinear Buckling ◽  
Foundation Model ◽  
Nonlinear Buckling Analysis

Nonlinear buckling analysis for honeycomb auxetic-core sandwich toroidal shell segments with CNT-reinforced face sheets surrounded by elastic foundations under the radial pressure is presented in this study. The basic equation system of shells is established based on the von Kármán–Donnell nonlinear shell theory, combined with Stein and McElman approximation. Meanwhile, the foundation-shell elastic interaction is simulated by the foundation model based on the Pasternak assumption. The Galerkin procedure is utilized to achieve the pre-buckling and post-buckling responses for the shell, from which the radially critical buckling load is determined. Numerical analysis shows the various influences of auxetic-core layer, CNT-reinforced face sheets, and elastic foundation on the pre-buckling and postbuckling behavior of sandwich shells with CNT reinforced face sheets.

scholarly journals Instability analysis of a filament-wound composite tube subjected to compression/bending

2019 ◽  
Vol 28 ◽  
pp. 096369351987741
Author(s):  
Gyula Szabó ◽  
Károly Váradi
Keyword(s):  
Failure Modes ◽  
Slenderness Ratio ◽  
Equivalent Stress ◽  
Bending Test ◽  
Test Machine ◽  
Fe Model ◽  
Rubber Tube ◽  
Nonlinear Buckling ◽  
Cross Sectional ◽  
Composite Tube

The aim of this study is to investigate the global buckling of a relatively long composite cord–rubber tube subjected to axial compression and its cross-sectional instability due to bending by a macromechanical nonlinear finite element (FE) model (nonlinear buckling analysis). Composite reinforcement layers are modelled as transversely isotropic ones, while elastomer liners are described by a hyperelastic material model that assumes incompressibility. Force–displacement, equivalent strain, equivalent stress results along with oblateness and curvature results for the complete process have been presented. It is justified that bending leads to ovalization of the cross section and results in a loss of the load-carrying capacity of the tube. Strain states in reinforcement layers have been presented, which imply that the probable failure modes of the reinforcement layers are both delamination and yarn-matrix debonding. There is a significant increase in strains due to cross-sectional instability, which proves that the effect of cross-sectional instability on material behaviour of the tube is crucial. A parametric analysis has been performed to investigate the effect of the member slenderness ratio on cross-sectional instability of the composite tube. It shows that Brazier force is inversely proportional to the slenderness ratio. It further shows that higher oblateness parameters occur in case of a lower slenderness ratio and that cross-sectional instability takes place at a lower dimensionless displacement in case of a lower slenderness ratio. FE results have been validated by a compression/bending test experiment conducted on a tensile test machine.

Finite Element Analysis of Drilling Frame on Down-the-Hole Drill Based on Mechanical Mechanics and Mechanical Properties

2014 ◽  
Vol 908 ◽  
pp. 282-286
Author(s):  
Wan Rong Wu ◽  
Lin Chen
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Working Condition ◽  
Slenderness Ratio ◽  
Stress And Strain ◽  
Limit States ◽  
Element Analysis ◽  
Practical Engineering ◽  
Structure Strength ◽  
Strength And Stiffness

Drilling frame on TD165CH Down-The-Hole Drill that has large slenderness ratio and be longer than 10m is one component of Down-The-Hole drill which is mainly subjected to load.In the process of drilling, drilling frame is not only subjected to loads which are like tensile, compression and torsion and so on, and be under the influence of impacting and vibration of impactor,the situation of force is complicated.By analysing of working condition of Down-The-Hole drill,there get all kinds of limit states of typical working conditions, and then using Ansys doing finite element analysis, there get distribution of the stress and strain of drilling frame and the result of modal analysis to check whether drilling frame meets the requirements of strength and stiffness or not,and whether it is possible to resonate with the impactor or not.By analysis,Structure strength and stiffness of drilling Frame on TD165CH Down-The-Hole drill meet the requirements of practical engineering, and drilling Frame does not resonate with the impactor.

Linear Buckling Analysis Considering No-compression Property of Metal Grid Shells Stiffened by Tension Braces

2021 ◽  
Vol 62 (3) ◽  
pp. 195-205
Author(s):  
Kenji Yamamoto ◽  
Hayato Utebi
Keyword(s):  
Geometrical Nonlinearity ◽  
Buckling Analysis ◽  
Nonlinear Buckling ◽  
Compression Property ◽  
Buckling Behavior ◽  
Metal Grid ◽  
Linear Buckling ◽  
Nonlinear Buckling Analysis ◽  
Linear Buckling Analysis ◽  
Lattice Shells

In order to analyze the buckling behavior of lattice shells stiffened by cables or slender braces without pre-tension, it is necessary to consider the no-compression property of braces. This paper proposes an innovative method of linear buckling analysis that considers the no-compression property of braces. Moreover, in order to examine the proposed method's validity, its results are compared with the results from a nonlinear buckling analysis with geometrical nonlinearity and material nonlinearity to express the no-compression property of braces. The results show that the proposed method can well-predict the buckling behaviors of lattice shells stiffened by tension braces.

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