Nonlinear Buckling Analysis of Wind Turbine Towers

2011 ◽  
Vol 383-390 ◽  
pp. 6469-6475
Author(s):  
Qing Cao ◽  
Yang Li ◽  
Hao Zhang
Keyword(s):  
Wind Turbine ◽  
Buckling Load ◽  
Plastic Buckling ◽  
Nonlinear Buckling ◽  
Integration Algorithm ◽  
Critical Buckling Load ◽  
Initial Imperfections ◽  
Elastic Plastic ◽  
Post Buckling ◽  
Wind Turbine Towers

Wind turbine towers are belonging to towering cylinder shell structures, which are easy to appear buckling instability under wind or other complicated loads, and on which integral elastic-plastic buckling analyses have great theoretical and practical significances. This paper used large deflection nonlinear pre-buckling and Koiter initial post-buckling theories, and adopted the finite element scheme of updated integration algorithm and LDC nonlinear solution method, then analyzed the linear buckling, elastic-plastic static buckling, and post-buckling response of the towers with initial imperfections in different location and size. It has obtained that: 1) the critical load of towers with elastic-plastic buckling is much smaller than it with elastic buckling; 2) gravity has certain influence on the critical buckling load; 3) the critical buckling load is insensitive to initial imperfections, meanwhile the imperfections which located on the top or the bottom of the tower are inferior for the stability of tower.

Buckling Load Estimation of Two-way Grid Domes Stiffened by Diagonal Braces Under Vertical Load

2021 ◽  
Vol 62 (1) ◽  
pp. 7-23
Author(s):  
Shiro Kato ◽  
Shoji Nakazawa ◽  
Yoichi Mukaiyama ◽  
Takayuki Iwamoto
Keyword(s):  
Slenderness Ratio ◽  
Fem Analysis ◽  
Buckling Load ◽  
Vertical Load ◽  
Imperfection Sensitivity ◽  
Plastic Buckling ◽  
Elastic Plastic ◽  
Alternative Formula ◽  
Efficient Scheme ◽  
Estimation Scheme

The present study proposes an efficient scheme to estimate elastic-plastic buckling load of a shallow grid dome stiffened by diagonal braces. The dome is circular in plan. It is assumed to be subject to a uniform vertical load and to be supported by a substructure composed of columns and anti-earthquake braces. Based on FEM parametric studies considering various configurations and degrees of local imperfections, a set of formulations are presented to estimate the elastic-plastic buckling load. In the scheme, the linear buckling load, elastic buckling load, and imperfection sensitivity are first presented in terms of related parameters, and the elasticplastic buckling load is then estimated by a semi-empirical formula in terms of generalized slenderness ratio using a corresponding plastic load. For the plastic load, the present scheme adopts a procedure that it is calculated by a linear elastic FEM analysis, while an alternative formula for the plastic load is also proposed based on a shell membrane theory. The validity of the estimation scheme is finally confirmed through comparison with the results based on FEM nonlinear analysis. The formulations are so efficient and simple that the estimation may be conducted for preliminary design purposes almost with a calculator. .

scholarly journals Study of the Bearing Capacity of Stiffened Tall Offshore Wind Turbine Towers during the Erection Phase

Energies ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 5102
Author(s):  
Yu Hu ◽  
Jian Yang ◽  
Charalampos Baniotopoulos
Keyword(s):  
Wind Energy ◽  
Bearing Capacity ◽  
Wind Turbine ◽  
Structural Response ◽  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
Nonlinear Buckling ◽  
Wind Turbine Towers ◽  
Nonlinear Buckling Analysis

Offshore wind energy is a rapidly maturing renewable energy technology that is poised to play an important role in future energy systems. The respective advances refer among others to the monopile foundation that is frequently used to support wind turbines in the marine environment. In the present research paper, the structural response of tall wind energy converters with various stiffening schemes is studied during the erection phase as the latter are manufactured in modules that are assembled in situ. Rings, vertical stiffeners, T-shaped stiffeners and orthogonal stiffeners are considered efficient stiffening schemes to strengthen the tower structures. The loading bearing capacity of offshore monopile wind turbine towers with the four types of stiffeners were modeled numerically by means of finite elements. Applying a nonlinear buckling analysis, the ultimate bearing capacity of wind turbine towers with four standard stiffening schemes were compared in order to obtain the optimum stiffening option.

Nonlinear Buckling Analysis of Shallow Spherical Shell under Uniform Pressure and Temperature Field

2013 ◽  
Vol 753-755 ◽  
pp. 1114-1118
Author(s):  
Yong An Zhu ◽  
Fan Wang
Keyword(s):  
Temperature Field ◽  
Spherical Shell ◽  
Buckling Load ◽  
Shallow Spherical Shell ◽  
Effect Of Temperature ◽  
Uniform Pressure ◽  
Nonlinear Buckling ◽  
Critical Buckling Load ◽  
Material Texture ◽  
Nonlinear Buckling Analysis

Shallow spherical shell is an important kind of sensor elastic element. Because of the particular metal material texture, it can work under high temperature field. The nonlinear buckling problems of shallow spherical shell in load and temperature filed are very important. In this paper, nonlinear buckling of shallow spherical shell under uniform pressure and temperature field in simply supported boundary conditions is studied by the modified iteration method, and the analytic formulas for determining the critical buckling load are obtained. The effect of temperature field on critical buckling load and critical geometrical parameter are discussed.

A New Shape of Snaked-Lay Pipeline

2011 ◽  
Vol 250-253 ◽  
pp. 2829-2832
Author(s):  
Yu Xiao Liu ◽  
Tao Ge ◽  
Xin Li ◽  
Jing Zhou
Keyword(s):  
Finite Element ◽  
Nonlinear Finite Element ◽  
Buckling Load ◽  
Lateral Buckling ◽  
Critical Buckling Load ◽  
Post Buckling ◽  
The Moment

Snaked-lay pipeline is an effective method for control lateral buckling of pipeline, which is used widely. For design of snaked-lay pipeline the key is how to control lateral buckling of pipeline, namely, the lateral buckling is triggered at the designed location, the moment and strain of post buckling are acceptable. A new shape of snaked-lay pipeline is presented. Based on ANSYS, nonlinear finite element of pipeline is built. Comparisons show that the critical buckling load, moment and strain of post-buckling are all reduced for the new shape of snaked-lay pipeline.

scholarly journals Buckling and Post-Buckling Behavior of Uniform and Variable-Density Lattice Columns Fabricated Using Additive Manufacturing

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3539 ◽  
Author(s):  
Aamer Nazir ◽  
Ahmad Bin Arshad ◽  
Jeng-Ywan Jeng
Keyword(s):  
Lattice Structure ◽  
Weight Ratio ◽  
High Strength ◽  
Variable Density ◽  
Buckling Load ◽  
Uniform Density ◽  
Lattice Structures ◽  
Critical Buckling Load ◽  
Buckling Behavior ◽  
Post Buckling

Lattice structures are known for their high strength-to-weight ratio, multiple functionalities, lightweight, stiffness, and energy absorption capabilities and potential applications in aerospace, automobile, and biomedical industry. To reveal the buckling (global and local) and post-buckling behavior of different lattice morphologies, both experimental and simulation-based studies were carried out. Additionally, a variable-density lattice structure was designed and analyzed to achieve the optimal value of critical buckling load. Latticed columns were fabricated using polyamide 12 material on multi jet fusion 3D printer. The results exhibited that the buckling in lattice columns depends on the distribution of mass, second moment of inertia I, diameter and position of vertical beams, number of horizontal or inclined beams, and location and angle of the beams that support the vertical beams. The number of horizontal and inclined beams and their thickness has an inverse relation with buckling; however, this trend changes after approaching a critical point. It is revealed that vertical beams are more crucial for buckling case, when compared with horizontal or inclined beams; however, material distribution in inclined or horizontal orientation is also critical because they provide support to vertical beams to behave as a single body to bear the buckling load. The results also revealed that the critical buckling load could be increased by designing variable density cellular columns in which the beams at the outer edges of the column are thicker compared with inner beams. However, post-buckling behavior of variable density structures is brittle and local when compared with uniform density lattice structures.

Effect of Imperfections on the Plastic Buckling of Rectangular Plates

1975 ◽  
Vol 42 (1) ◽  
pp. 115-120 ◽  
Author(s):  
K. W. Neale
Keyword(s):  
Experimental Data ◽  
Variational Principle ◽  
Buckling Load ◽  
Rectangular Plates ◽  
Plastic Buckling ◽  
Simply Supported ◽  
Initial Imperfections

The effect of initial imperfections in geometry on the plastic buckling of simply supported compressed rectangular plates is examined. The analysis, which is based on the application of a Reissner-type variational principle, indicates that the buckling load can be highly imperfection-sensitive; and that a consideration of small imperfections in geometry could provide results which compare favorably with experimental data.

Non-Probabilistic Models of Uncertainty in the Nonlinear Buckling of Shells With General Imperfections: Theoretical Estimates of the Knockdown Factor

1989 ◽  
Vol 56 (2) ◽  
pp. 403-410 ◽  
Author(s):  
Yakov Ben-Haim ◽  
Isaac Elishakoff
Keyword(s):  
Probabilistic Models ◽  
Theoretical Estimate ◽  
Initial Imperfection ◽  
Theoretical Models ◽  
Buckling Load ◽  
Dimensional Euclidean Space ◽  
Theoretical Treatment ◽  
Nonlinear Buckling ◽  
Initial Imperfections ◽  
Geometrical Imperfections

A non-probabilistic, set-theoretical treatment of the buckling of shells with uncertain initial geometrical imperfections is presented. The minimum buckling load is determined as a function of the parameters which describe the (generally infinite) range of possible initial imperfection profiles of the shell. The central finding of this paper is a theoretical estimate of the knockdown factor as a function of the characteristics of the uncertainty in the initial imperfections. Two classes of set-theoretical models are employed. The first class represents the range of variation of the most significant N Fourier coefficients by an ellipsoidal set in N-dimensional Euclidean space. The minimum buckling load is then explicitly evaluated in terms of the shape of the ellipsoid. In the second class of models, the uncertainty in the initial imperfection profile is expressed by an envelope of functions. The bounding functions of this envelope can be viewed as a radial tolerance on the shape. It is demonstrated that a non-probabilistic model of uncertainty in the initial imperfections of shells is successful in determining the minimum attainable buckling load of an ensemble of shells and that such an approach is computationally feasible.

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