Differential Equation for Evaluating Transverse Buckling Behavior of Tensile Armour Wires

2014 ◽  
Author(s):  
Svein Sævik ◽  
Guomin Ji
Keyword(s):  
Differential Equation ◽  
Numerical Study ◽  
Failure Criteria ◽  
Fe Analysis ◽  
Design Criteria ◽  
Transverse Tensile ◽  
Flexible Pipes ◽  
Buckling Behavior ◽  
Transverse Stability ◽  
Bending Behaviour

The present paper addresses aspects related to transverse tensile armour buckling in flexible pipes. An analytical model for evaluating the tensile armour buckling capacity is presented based on formulating the linearised differential equation describing the transverse stability of the thin curved wire assuming no friction. This is followed by a numerical study based on FE analysis to evaluate the extra capacity from friction during cyclic bending behaviour and where the yield stress is used as the failure criteria. The results is then compared to test data and a design criteria for transverse tensile armour buckling proposed.

An Analytical Treatment of Buckling and Instability of Tensile Armors in Flexible Pipes

2017 ◽  
Vol 139 (4) ◽  
Author(s):  
Svein Sævik ◽  
Mats J. Thorsen
Keyword(s):  
Differential Equation ◽  
Test Data ◽  
Local Buckling ◽  
Analytical Models ◽  
Ultimate Capacity ◽  
Analytical Treatment ◽  
Alternative Models ◽  
Outer Sheath ◽  
Flexible Pipes ◽  
Transverse Stability

The present paper addresses aspects related to local buckling and instability of tensile armors in flexible pipes. Analytical models for evaluating the tensile armor buckling capacity in both transverse (radial and lateral) directions are presented based on formulating the linearized differential equation describing transverse stability of the thin curved wire assuming no friction. Then analytical models for the ultimate capacity of the outer sheath and antibuckling tape are formulated and a combined criterion for radial instability is proposed based on considering radial buckling of the tensile armor, wire yield failure, and the ultimate capacity of the outer sheath and tape. Thereafter, a study is performed comparing the proposed models with test data and alternative models available in the literature.

Numerical Study of the Effect of Geometry and Boundary Conditions on the Collapse Behaviour of Stocky Stiffened Panels

2012 ◽  
Vol 154 (A2) ◽  
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Ultimate Strength ◽  
Material Properties ◽  
Finite Element Modelling ◽  
Numerical Study ◽  
Fe Analysis ◽  
Stiffened Panels ◽  
Element Modelling ◽  
Geometric Configurations

This study aims at studying different configurations of the stiffened panels in order to identify robust configurations that would not be much sensitive to the imprecision in boundary conditions that can exist in experimental set ups. A numerical study is conducted to analyze the influence of the stiffener’s geometry and boundary conditions on the ultimate strength of stiffened panels under uniaxial compression. The stiffened panels with different combinations of mechanical material properties and geometric configurations are considered. The four types of stiffened panels analysed are made of mild or high tensile steel and have bar, ‘L’ and ‘U’ stiffeners. To understand the effect of finite element modelling on the ultimate strength of the stiffened panels, four types of FE models are investigated in FE analysis including 3 bays, 1/2+1+1/2 bays, 1+1 bays and 1 bay with different boundary conditions.

scholarly journals A Numerical Study of Chemical Reaction in a Nanofluid Flow Due to Rotating Disk in the Presence of Magnetic Field

2021 ◽  
Author(s):  
Muhammad Ramzan ◽  
Poom Kumam ◽  
Kottakkaran Sooppy Nisar ◽  
Ilyas Khan ◽  
Wasim Jamshed
Keyword(s):  
Differential Equation ◽  
Radial Velocity ◽  
Chemical Reaction ◽  
Axial Velocity ◽  
Numerical Study ◽  
Tangential Velocity ◽  
Rotating Disk ◽  
Partial Differential ◽  
Suction Parameter ◽  
Matlab Programming

Abstract In this paper, a numerical study of MHD steady flow due to the rotating disk with chemical reaction was explored. Effect of different parameters such as Schmidt number, chemical reaction parameter, Prandtl number, Suction parameter, heat absorption/generation parameter, Nano-particle concentration, Reynold number, Magnetic parameter, skin friction, shear stress, temperature distribution, Nusselt number, mass transfer rate, radial velocity, axial velocity, and tangential velocity was analyzed and discussed. For the simplification of non-linear partial differential equations (PDEs) into the nonlinear ordinary differential equation (ODEs), the method of Similarity transformation was employed, and the resulting partial differential equation was solved by using finite difference method through MATLAB programming. This work's remarkable finding is that with the expansion of nanoparticle concentration radial velocity, tangential velocity and temperature of the fluid was enhanced but reverse reaction for axial velocity. Furthermore, the present results are found to be in excellent agreement with previously published work.

scholarly journals Numerical study of the transverse stability of the Peregrine solution

2020 ◽  
Vol 145 (1) ◽  
pp. 36-51
Author(s):  
Christian Klein ◽  
Nikola Stoilov
Keyword(s):  
Numerical Study ◽  
Transverse Stability

Numerical Study of Micropolar Fluid Flow Past an Impervious Sphere

2018 ◽  
Vol 388 ◽  
pp. 344-349
Author(s):  
D.V. Jayalakshmamma ◽  
P.A. Dinesh ◽  
D.V. Chandrashekhar
Keyword(s):  
Differential Equation ◽  
Fluid Flow ◽  
Micropolar Fluid ◽  
Similarity Transformation ◽  
Numerical Study ◽  
Transformation Method ◽  
Governing Equations ◽  
Shooting Technique ◽  
Micropolar Fluid Flow ◽  
Incompressible Micropolar Fluid

The numerical study of axi-symmetric, steady flow of an incompressible micropolar fluid past an impervious sphere is presented by assuming uniform flow far away from the sphere. The continuity, linear and angular momentum equations are considered for incompressible micropolar fluid in accordance with Eringen. The governing equations of the physical problem are transformed to ordinary differential equation with variable co-efficient by using similarity transformation method. The obtained differential equation is then solved numerically by assuming the shooting technique. The effect of coupling and coupling stress parameter on the properties of the fluid flow is studied and demonstrated by graphs.

Soil Stresses on Carbon Steel Pipe Undergoing Uplift

2016 ◽  
Vol 835 ◽  
pp. 439-443
Author(s):  
Yuri D. Costa ◽  
Lucas S. Moraes ◽  
Carina L. Costa
Keyword(s):  
Carbon Steel ◽  
Relative Density ◽  
Numerical Study ◽  
Three Dimensional ◽  
Soil Mass ◽  
Steel Pipe ◽  
Surcharge Loading ◽  
Flexible Pipes ◽  
Stress Variations

This paper presents a three-dimensional numerical study to evaluate the variations in stresses in the soil mass surrounding a carbon steel pipe class API 5L X60 submitted to uplift due to ground elevation. Analyses were carried out for soil relative density, pipe stiffness and surficial surcharge loading. Results have shown that stress variations due to uplift are lower for looser backfill soils and flexible pipes. Stress variations in pipe invert are meaningful in the vicinity of the region between stable and unstable soil masses.

Dropped Object Analysis Using Non-Linear Dynamic FE Analysis

2014 ◽  
Author(s):  
Kwanghyun Ahn ◽  
Minsung Chun ◽  
Sangmin Han ◽  
Kibok Jang ◽  
Yongsuk Suh
Keyword(s):  
Material Properties ◽  
Failure Criteria ◽  
Offshore Structures ◽  
Linear Analysis ◽  
Fe Analysis ◽  
Structural Safety ◽  
Design Consideration ◽  
Linear Dynamic ◽  
Non Linear

For the last few decades, necessity of direct non-linear FE analysis has been increasing for the accidental events at the vessel/offshore structures. One of major areas for the accidental design, dropped object analysis using non-linear analysis is indispensable for the verification of structural safety at the design process. This paper is concerned with the methodology, conditions, and design consideration of dropped object analysis using dynamic FE analysis. By comparing the results from direct FE analyses to those from simplified energy method described in DNV-RP-C204, necessities and advantages of direct non-linear analysis can be verified. In this paper, the effect of analysis condition is investigated using parametric study. The results are influenced by the application of failure criteria according to the rule requirements, application of material properties, dropping position, condition of the object, and so on. This study can suggest appropriate determination of the methodology and condition for the dropped object analysis using direct FE analysis.

Enhanced Film Cooling Effectiveness by Integration of Horn-Shaped and Cylindrical Holes

2017 ◽  
Author(s):  
Rui Zhu ◽  
Gongnan Xie ◽  
Terrence W. Simon
Keyword(s):  
Film Cooling ◽  
Numerical Study ◽  
Turbine Blades ◽  
Cylindrical Hole ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Transverse Tensile ◽  
First Case ◽  
Cylindrical Holes ◽  
Shaped Hole

In search of improved cooling of gas turbine blades, the thermal performances of two different film cooling hole geometries (horn-shaped and cylindrical) are investigated in this numerical study. The horn-shaped hole is designed from a cylindrical hole by expanding the hole in the transverse direction to double the hole size at the exit. The two hole shapes are evaluated singly and in tandem. The tandem geometry assumes three configurations made by locating the cylindrical hole at three different positions relative to the horn-shaped hole such that their two axes remain parallel to one another. One has the cylindrical hole downstream from the center of the horn-shaped hole, a second has the cylindrical hole to the left of (as seen by the flow emerging from the horn-shaped hole) and at the same streamwise location as the horn-shaped hole (θ = 90°) and the third has an intermediate geometry between those two geometries (downstream and to the left of the horn-shaped hole - θ = 45°). It is shown from the simulation results that the cooling effectiveness values for the θ = 45° and 90° cases are much better than that for θ = 0° (the first case), and the configuration with θ = 45° exhibits the best cooling performance of the three tandem arrangements. These improvements are attributed to the interaction of vortices from the two different holes, which weakens the counter-rotating vortex pairs inherent to film cooling jet to freestream interaction, counteracts with the lift forces, enhances transverse tensile forces and, thus, enlarges the film coverage zone by widening the flow attachment region. Overall, this research reveals that integration of horn-shaped and cylindrical holes provides much better film cooling effectiveness than cases where two cylindrical film cooling holes are applied with the same tandem configuration.

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