Shakedown Analysis of Offshore Platform Under Varied Combined Loading

2011 ◽  
Author(s):  
Qiyi Zhang ◽  
Sheng Dong
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Offshore Platform ◽  
Static Equilibrium ◽  
Combined Loading ◽  
Shakedown Analysis ◽  
Elastic Plastic ◽  
Element Method

Based on static Melan shakedown theorem, an elastic-plastic finite element method is presented to analyze the shakedown of saturated undrained foundation due to varied combined loadings, and the shakedown loadings under different patterns of loading combination are compared. At the same time, a comparison is given between the shakedown failure envelop under varied combined loading and the failure envelop of ultimate bearing capacity under static equilibrium, and it is found that the shakedown loading under varied combined loading is less than the ultimate bearing capacity under combined loading.

Study on Buckling of an H-Shaped Steel Member with Initial Geometric Imperfection

2012 ◽  
Vol 204-208 ◽  
pp. 3226-3229
Author(s):  
Peng Niu ◽  
Gang Yang ◽  
Chun Fu Jin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Compressive Load ◽  
Bending Moment ◽  
Ultimate Bearing Capacity ◽  
Geometric Imperfection ◽  
Elastic Plastic ◽  
Axial Compressive Load ◽  
Initial Geometric Imperfection

Based on Ježek method of computing the elastic-plastic buckling of the member under the axial compressive load and the bending moment, considering the initial imperfection, the analytical expressions of calculating the ultimate load of buckling about the neutral axis with the maximum moment of inertia for an H-shaped member are derived. Using the elastic-plastic finite element method and the theory of nonlinear buckling, the impact by initial geometric imperfections on the H-shaped steel member under the axial compressive load and the bending moment are analyzed and the numerical solutions of ultimate bearing capacity are obtained. By compared with the values of the finite element method (FEM), it shows that the analytical method in this paper is valid. The results of the example show that the presence of initial imperfections reduces the ultimate bearing capacity of the steel member to a great extent. It is also found that the influence of the initial geometric imperfection on the ultimate bearing capacity of member is smaller when the bending moment increases.

Comparison of Analytical Solutions with Finite Element Solutions for Ultimate Bearing Capacity of Strip Footings

2013 ◽  
Vol 353-356 ◽  
pp. 3294-3303
Author(s):  
Zi Hang Dai ◽  
Xiang Xu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Analytical Solutions ◽  
Numerical Solutions ◽  
Slip Surface ◽  
Ultimate Bearing Capacity ◽  
The Finite Element Method ◽  
Strip Footings ◽  
Element Method

The finite element method is used to compute the ultimate bearing capacity of a fictitious strip footing resting on the surface of c-φ weightless soils and a real strip footing buried in the c-φ soils with weight. In order to compare the numerical solutions with analytical solutions, the mainly existing analytical methods are briefly introduced and analyzed. To ensure the precision, most of analytical solutions are obtained by the corresponding formulas rather than table look-up. The first example shows that for c-φ weightless soil, the ABAQUS finite element solution is almost identical to the Prandtls closed solutions. Up to date, though no closed analytical solution is obtained for strip footings buried in c-φ soils with weight, the numerical approximate solutions obtained by the finite element method should be the closest to the real solutions. Apparently, the slip surface disclosed by the finite element method looks like Meyerhofs slip surface, but there are still some differences between the two. For example, the former having an upwarping curve may be another log spiral line, which begins from the water level of footing base to ground surface rather than a straight line like the latter. And the latter is more contractive than the former. Just because these reasons, Meyerhofs ultimate bearing capacity is lower than that of the numerical solution. Comparison between analytical and numerical solutions indicates that they have relatively large gaps. Therefore, finite element method can be a feasible and reliable method for computations of ultimate bearing capacity of practical strip footings.

Finite Element Analysis for Unstiffened Overlapped CHS K-Joints Welded in Different Ways

2012 ◽  
Vol 446-449 ◽  
pp. 533-536
Author(s):  
Xiu Li Wang ◽  
Peng Chen ◽  
Wen Wei Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Ultimate Capacity ◽  
The Finite Element Method ◽  
Element Analysis ◽  
Element Method

In this paper，the ultimate bearing capacity of unstifened overlapped CHS K-joints is investigated by using the finite element method with influence of weld and non-weld on joint ultimate capacity under brace different bearing capacity. with angle of chord and brace is increasing ultimate capacity to lowed more and more small，which hidden weld is non-weld by one brace is pulled and other is pressured. ultimate capacity no influence to hidden welded and non-welded by both brace is pulled.

scholarly journals Analysis of the stressed-strained state of the foundation-shell at interaction with the elastic-plastic medium

2021 ◽  
pp. 105-112
Author(s):  
Maksym Vabishchevich ◽  
Gherman Zatyliuk
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Numerical Methods ◽  
Bearing Capacity ◽  
The Finite Element Method ◽  
Plastic Medium ◽  
Soil Base ◽  
Elastic Plastic ◽  
The Impact ◽  
Element Method

On the basis of modern numerical implementations of the finite element method the article presents the justification of the adequacy of the method of solving the problems of structures straining in their contact interaction with the elastic-plastic nonlinear soil medium. Compatible calculations of structures and nonlinear bases, which are described by modern mechanical and soil models within one problem is a significant technical problem. The solution of the assigned tasks is possible only within the framework of numerical methods, the most common of which is the finite element method (FEM). The construction of the computational finite element model raises many complex questions that require additional detailed study. In addition, the compliance with the state building norms and regulations is an important factor for further practical use. The use of numerical methods in the calculation of machines and structures, taking into account their interaction with the elastic-plastic medium is largely determined by the complexity or even impossibility of analytical calculation due to the complexity of structural schemes, heterogeneity of material features, uneven soil layers, implementation of step-by-step work execution technologies and so on. The combination of the latest achievements in the field of structural mechanics and soil mechanics is a promising direction for the development of effective approaches to building discrete models of space systems “structure-nonlinear base” for solving applied problems. The use of the developed method allows to significantly specify the structures stress state interacting with the soil base, and to significantly specify the impact on the calculated level of the base bearing capacity. Only the simultaneous consideration of the nonlinear resistance of the soil base together with the plasticity and the structure destruction in the numerical simulation of the foundation-shell load provided good agreement with the natural experiment data as to the type of the boundary state and the bearing capacity level.

scholarly journals ANALYSIS OF ULTIMATE BEARING CAPACITY OF FOOTING OF TWO LAYERED CLAYEY SOIL SYSTEM BY RIGID PLASTIC FINITE ELEMENT METHOD

2013 ◽  
Vol 19 (43) ◽  
pp. 881-885
Author(s):  
Kazuhiro KANEDA ◽  
Tomohiro TANIKAWA ◽  
Junji HAMADA ◽  
Satoru OHTSUKA ◽  
Masamichi AOKI
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Bearing Capacity ◽  
Clayey Soil ◽  
Ultimate Bearing Capacity ◽  
Rigid Plastic ◽  
Soil System ◽  
Element Method

The Equilibrium Cell-Based Smooth Finite Element Method for Shakedown Analysis of Structures

2019 ◽  
Vol 16 (05) ◽  
pp. 1840013 ◽  
Author(s):  
P. L. H. Ho ◽  
C. V. Le ◽  
T. Q. Chu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Optimization Problem ◽  
Conic Programming ◽  
Equilibrium Equations ◽  
Shakedown Analysis ◽  
Numerical Examples ◽  
Elastic Stresses ◽  
Gauss Points ◽  
Element Method

This paper presents a novel equilibrium formulation, that uses the cell-based smoothed method and conic programming, for limit and shakedown analysis of structures. The virtual strains are computed using straining cell-based smoothing technique based on elements of discretized mesh. Fictitious elastic stresses are also determined within the framework of finite element method (CS-FEM)-based Galerkin procedure, and equilibrium equations for residual stresses are satisfied in an average sense at every cell-based smoothing cell. All constrains are imposed at only one point in the smoothing domains, instead of Gauss points as in a standard FEM-based procedure. The resulting optimization problem is then handled using the highly efficient solvers. Various numerical examples are investigated, and obtained solutions are compared with available results in the literature.

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