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. .

The Secant Method for Buckling Load of Centrally Compressed Member with Residual Stresses

2013 ◽  
Vol 749 ◽  
pp. 54-59
Author(s):  
Jian Qin ◽  
Jin Miao Zhang ◽  
Yong Jun Xia
Keyword(s):  
Residual Stresses ◽  
Axial Strain ◽  
Nonlinear Function ◽  
Buckling Load ◽  
New Method ◽  
Fast Method ◽  
Plastic Buckling ◽  
Elastic Plastic ◽  
Iterative Calculation ◽  
Medium Length

A fast method for elastic-plastic buckling of centrally compressed members is put forward, which is suitable for the medium length column considering the effect of residual stresses. The problem of elastic-plastic buckling is simplified as a nonlinear function of axial strain, and the secant algorithm is built based on the nonlinear function. The advantages of the new method are discussed and the iterative calculation process is listed. The new method offers significant improvements in accuracy, robustness and calculation amount of the solution, which can be used for members with any type section. An example of I-shape member is calculated by the new method and the result is compared with the analytical solution. The contrast of the buckling load verifies the reliability of the new method.

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.

Elastic-Plastic FEM Analysis of Deformations of a Cylinder Subjected to Severe Uniaxial and Bilateral Compression by Flat Plates

1991 ◽  
Author(s):  
M. Gotoh ◽  
Y. Shibata
Keyword(s):  
Compressive Force ◽  
Fem Analysis ◽  
Plane Stress State ◽  
Deformation Pattern ◽  
Lateral Compression ◽  
The Finite Element Method ◽  
Ring Plane ◽  
Flat Plates ◽  
Elastic Plastic ◽  
Plastic Forming

Abstract Uni-lateral and bi-lateral elastic-plastic compressions of a circular cylinder with three different wall thicknesses by flat plates are numerically analysed by the Finite Element Method (FEM). J2-flow theory (J2F), and J2-Gotoh’s corner theory (J2G) which was previously proposed by one of the authors are used as the constitutive equations. In the case of uni-lateral compression, the cylinder is compressed up to a completely flattened shape, which is considered a kind of plastic forming processes. The deformed shapes and the compressive force are predicted better by J2G than by J2F. The spring-back behaviours are also analysed by imposing unloading process during deformation. The deformation process in the compression of a ring (plane stress state) and a spherical shell (axi-symmetric state) is also analysed. In the case of bi-lateral compression, the process is considered a kind of square-tube forming. In its final stage, the cylinder deforms into a completely unexpected shape which could be thought of as a square tube reinforced with ribs. The J2G allows the process to proceed at a lower compressive force than that for J2F. The effect of n-value (the strain-hardedning exponent) on the deformation pattern is also discussed.

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