The Buckling Analysis of Drill String in Inclined Wellbore with a Concave Curved Geometric Defect

2014 ◽  
Vol 670-671 ◽  
pp. 759-763
Author(s):  
Bing Kun Zhu
Keyword(s):  
Energy Method ◽  
Drill String ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Well Bore ◽  
Straight Line ◽  
Drilling String ◽  
Inclined Boreholes ◽  
Inclined Borehole ◽  
Geometric Defect

Some inclined boreholes have to be drilled in directional wells, but the track of inclined borehole is impossible to be a ideal straight line, there are always some geometric defects such as bending, thus the drilling string in it is bound to have initial bending due to the constraints of borehole, hence the drilling string in inclined borehole is usually a curved compressed rod. Its buckling nature is quite different from straight compressed rod, it is necessary to analyze it specially. In this paper the buckling problem of drill string in inclined borehole with a concave curved geometric defect is studied by energy method, the computing formula of buckling load for it was obtained. And the influence of initial concave bending on buckling load was discussed. The research indicates that when drilling string in inclined well bore has a initial concave bending, the greater the degree of initial bending of drill string, the greater its buckling load.

Buckling Analysis of Symmetric Cross-Ply Laminated Annular Plates with Carbon Nanotubes

2014 ◽  
Vol 592-594 ◽  
pp. 901-905
Author(s):  
Pankaj Kumar ◽  
Pandey Ramesh
Keyword(s):  
Carbon Nanotubes ◽  
Boundary Condition ◽  
Carbon Nanotube ◽  
Aspect Ratio ◽  
Energy Method ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Buckling Loads ◽  
Annular Plates ◽  
Buckling Behavior

The Paper presents the buckling response of composite annular plates with under uniform internal and external radial edge loads using energy method. For the equation of stability Trefftez rule is used. The paper consists of buckling behavior of laminate (90/0) s, influence of some parameters such as thickness, boundary condition, aspect ratio on buckling loads and modes are investigated. Present results are compared with other papers. In this paper the effect of % weight of carbon nanotube (MWCNT) on the buckling load is also investigated.

scholarly journals Assessment of the global stability of three-limbed steel tube latticed column using finite element modelling

2021 ◽  
Vol 2045 (1) ◽  
pp. 012021
Author(s):  
Y D Fu ◽  
X Y Dai ◽  
H D Zhang ◽  
K G Shang
Keyword(s):  
Finite Element ◽  
Global Stability ◽  
Steel Tube ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Elastic Buckling ◽  
Analysis Method ◽  
Element Analysis ◽  
Stability Performance ◽  
Geometric Defect

Abstract In order to study the stability performance of the three-limbed steel tube latticed column, the finite element numerical analysis method based on the structural stability theory is adopted. Firstly, the linear analysis of the three-limbed steel tube latticed column without diagonal lacing bar is carried out, and the calculation method of elastic buckling load considering the influence of shear deformation is obtained. Then, the elastic buckling analysis and elastoplastic buckling analysis three-limbed steel tube latticed column with diagonal lacing bar are carried out. The elastic buckling load and elastoplastic buckling load of three-limbed steel tube latticed column with diagonal lacing bar are studied when only the global initial geometric defects, only the member initial geometric defects, and both kinds of defects are considered at the same time. The results show that the direct finite element analysis method can be used to calculate the elastic buckling load of three-limbed steel tube latticed column with diagonal lacing bar, and the error is 6.67%. In the elastic analysis of three-limbed steel tube latticed column with diagonal lacing bar, the column global stability mainly depends on the global initial geometric defects, and the member initial geometric defect is negligible. And when two kinds of defects are applied at the same time, the structural buckling load is reduced by less than 0.20% compared to the global initial geometric defects. In the elastoplastic analysis, the column global stability is determined by both the global initial geometric defect and the member initial geometric defect. When both defects are applied at the same time, the structural buckling load decreases by less than 0.65% compared to the global initial geometric defect only, and 7.60% compared to the member initial geometric defects only. It can be concluded that there is little difference in the overall stability bearing capacity between the two kinds of defects.

RELIABILITY ASSESSMENT OF AXIALLY COMPRESSED COMPOSITE CYLINDRICAL SHELLS WITH RANDOM IMPERFECTIONS

2011 ◽  
Vol 11 (02) ◽  
pp. 215-236 ◽  
Author(s):  
MATTEO BROGGI ◽  
ADRIANO CALVI ◽  
GERHART I. SCHUËLLER
Keyword(s):  
Mathematical Models ◽  
Axial Compression ◽  
Cylindrical Shells ◽  
Reliability Assessment ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Experimental Results ◽  
Drastic Decrease ◽  
Different Types ◽  
Probability And Statistics

Cylindrical shells under axial compression are susceptible to buckling and hence require the development of enhanced underlying mathematical models in order to accurately predict the buckling load. Imperfections of the geometry of the cylinders may cause a drastic decrease of the buckling load and give rise to the need of advanced techniques in order to consider these imperfections in a buckling analysis. A deterministic buckling analysis is based on the use of the so-called knockdown factors, which specifies the reduction of the buckling load of the perfect shell in order to account for the inherent uncertainties in the geometry. In this paper, it is shown that these knockdown factors are overly conservative and that the fields of probability and statistics provide a mathematical vehicle for realistically modeling the imperfections. Furthermore, the influence of different types of imperfection on the buckling load are examined and validated with experimental results.

Finite Element Analysis on Axial-Torsional Coupled Vibration of Drill String

2011 ◽  
Vol 291-294 ◽  
pp. 1952-1956 ◽  
Author(s):  
Xue Liang Bi ◽  
Jian Wang ◽  
Zhan Lin Wang ◽  
Shi Hui Sun
Keyword(s):  
Finite Element ◽  
Coupled Model ◽  
Resonance State ◽  
Drill String ◽  
Hole Drilling ◽  
Drilling Process ◽  
Coupled Vibration ◽  
Element Analysis ◽  
Drilling String ◽  
Rotary Speed

In the drilling process, axial vibration, transverse vibration and torsional vibration happen to drilling string. And the coupled vibration is more complex. In the resonance state, drilling string collides with the wall, which causes serious damage on drilling string in a short time and results in economic loss to the drilling operation. In this paper, the regularity of coupled vibration is analyzed by using finite element method. The model of full-hole drilling strings is established. The distribution regularities of coupled resonant frequency are obtained through computer analysis. The coupled model is more accurate than single vibration model. And the gaps of high rotary speed resonance regions are larger. Resonance state can be avoided by changing rotary speed, and drilling accidents can be reduced.

The Energy Solutions for the Stability of Tower Crane

2012 ◽  
Vol 170-173 ◽  
pp. 3159-3165
Author(s):  
Ming Xin Huang ◽  
Jian Ping Xu ◽  
Jian Guo Wu
Keyword(s):  
Energy Method ◽  
Buckling Load ◽  
Tower Crane ◽  
The Stability ◽  
Design And Construction

The energy method is used to solve the buckling load of tower crane. It can conclude the effect law on the stability of different section parameters of tower crane and thus provides some references for the design and construction of tower crane.

Thermal buckling analysis of double-walled carbon nanotubes considering the small-scale length effect

2011 ◽  
Vol 225 (1) ◽  
pp. 248-256 ◽  
Author(s):  
A Ghorbanpour Arani ◽  
M Mohammadimehr ◽  
A R Saidi ◽  
S Shogaei ◽  
A Arefmanesh
Keyword(s):  
Temperature Change ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Small Scale ◽  
Buckling Mode ◽  
Critical Buckling Load ◽  
Winkler Model ◽  
Non Local ◽  
Double Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

In this article, the buckling analysis of a double-walled carbon nanotube (DWCNT) subjected to a uniform internal pressure in a thermal field is investigated. The effects of the temperature change, the surrounding elastic medium based on the Winkler model, and the van der Waals forces between the inner and the outer tubes are considered using the continuum cylindrical shell model. The small-length scale effect is also included in the present formulation. The results show that there is a unique buckling mode corresponding to each critical buckling load. Moreover, it is shown that the non-local critical buckling load is lower than the local critical buckling load. It is concluded that, at low temperatures, the critical buckling load for the infinitesimal buckling of a DWCNT increases as the magnitude of temperature change increases whereas at high temperatures, the critical buckling load decreases with the increasing of the temperature.

Buckling analysis of functionally graded annular sector plates resting on elastic foundations

2010 ◽  
Vol 225 (2) ◽  
pp. 312-325 ◽  
Author(s):  
A Naderi ◽  
A R Saidi
Keyword(s):  
Boundary Conditions ◽  
Elastic Foundation ◽  
Buckling Analysis ◽  
Functionally Graded ◽  
Buckling Load ◽  
Critical Buckling Load ◽  
Elastic Foundations ◽  
Annular Sector ◽  
Sector Plate ◽  
Annular Sector Plate

In this study, an analytical solution for the buckling of a functionally graded annular sector plate resting on an elastic foundation is presented. The buckling analysis of the functionally graded annular sector plate is investigated for two typical, Winkler and Pasternak, elastic foundations. The equilibrium and stability equations are derived according to the Kirchhoff's plate theory using the energy method. In order to decouple the highly coupled stability equations, two new functions are introduced. The decoupled equations are solved analytically for a plate having simply supported boundary conditions on two radial edges. Satisfying the boundary conditions on the circular edges of the plate yields an eigenvalue problem for finding the critical buckling load. Extensive results pertaining to critical buckling load are presented and the effects of boundary conditions, volume fraction, annularity, plate thickness, and elastic foundation are studied.

Buckling Analysis of Wind Power Tower Considering the Effect of Nonlinearity

2012 ◽  
Vol 256-259 ◽  
pp. 792-795
Author(s):  
Bo Song ◽  
Shuai Huang ◽  
Wen Shan He ◽  
Wei Wei
Keyword(s):  
Wind Power ◽  
Geometric Nonlinearity ◽  
Local Buckling ◽  
Element Model ◽  
Buckling Analysis ◽  
Buckling Load ◽  
Nonlinear Buckling ◽  
Buckling Behavior ◽  
Geometry Nonlinearity ◽  
Material And Geometric Nonlinearity

Based on the 3D finite element model of the wind power tower, buckling behavior of the wind power tower in different wind directions is analyzed, and the effect considering geometry nonlinearity and considering the material and geometry nonlinearity to the buckling analysis is studied. The results show when the ratio of the radius of the tower drum and the length of the element is 18.75, the calculated precision can reach 95%. Local buckling of the wind power tower first appears, and buckling load and displacement considering the material and geometric nonlinearity reduce 52% and 58% compared with that only considering geometry nonlinearity. The linear and nonlinear buckling load of the wind power tower which is 90° sidewind are 1.8 and 1.2 times than those facing the wind direction.

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