Research on Optimizing Precast Water Head on Preloading Filling Spiral Case of a Large-Scale Hydropower Station

2011 ◽  
Vol 243-249 ◽  
pp. 6183-6187
Author(s):  
Hai Lin Wu ◽  
Shi He Qin ◽  
Yao Li ◽  
Xiao Fan Du
Keyword(s):  
Finite Element Method ◽  
Large Scale ◽  
Mechanical Characteristics ◽  
Nonlinear Finite Element ◽  
Hydropower Station ◽  
Nonlinear Finite Element Method ◽  
Contact State ◽  
Water Head ◽  
Spiral Case ◽  
Pumped Storage

In combination with the practice of a pumped storage hydropower station, a 3-D nonlinear finite element method on the preloading filling spiral case is carried out to compare and analyze stresses of the steel spiral case and hoop reinforcement, the stress and bearing ratio of the surrounding concrete, the contact state between the spiral case and concrete in different precast water head. The results indicate that the stress of the surrounding concrete will get better with the increasing of precast water head. But there is a distance between the spiral case and the surrounding concrete when the water head is excessive, which is unhelpful for operating of the unit. When the precast water head of the spiral case is 439m or so, it can play a greater degree of mechanical characteristics of steel and concrete under the premise of operating stably of the unit.

Influence of Cutout Position on Buckling of Large-Scale Thin-Walled Cylindrical Shell of Desulphurizing Tower with Welding Induced Imperfection under Wind Loading

2014 ◽  
Vol 687-691 ◽  
pp. 68-72
Author(s):  
Qian Li ◽  
Deng Feng Wang
Keyword(s):  
Finite Element Method ◽  
Cylindrical Shell ◽  
Large Scale ◽  
Cylindrical Shells ◽  
Nonlinear Finite Element ◽  
Wind Loading ◽  
Nonlinear Finite Element Method ◽  
Geometrical Imperfection ◽  
Thin Walled ◽  
Steel Cylindrical Shell

Not only the geometrical imperfection induced by welding but also cutouts will influence the buckling of large-scale thin-walled steel cylindrical shell under wind loading. Based on the practical cylindrical shells of a desulphurizing absorption tower, in consideration of the correlation between welding induced imperfection and circular cutouts, the influence of cutout position on buckling of cylinder under wind loading is investigated by nonlinear finite element method. The results indicate that the buckling capacity varies slightly when the cutout position moves along meridional direction in the neighboring region of welding imperfection. The buckling capacity varies significantly when the cutout position moves circumferentially as the cutout is located in the welding imperfection. The buckling capacity reaches the minimum value as the cutout is located in the buckle center of cylindrical shells without cutout.

Study on Antiseismic Measures of Tailings Dam

2011 ◽  
Vol 90-93 ◽  
pp. 44-47
Author(s):  
Jian Ping Pan ◽  
Sheng Yi Wang ◽  
Shui Tai Xu
Keyword(s):  
Finite Element Method ◽  
Rock Pressure ◽  
Deformation Characteristic ◽  
Nonlinear Finite Element ◽  
Stone Column ◽  
Tailings Dam ◽  
Nonlinear Finite Element Method ◽  
Reinforcement Effect ◽  
Earthquake Action ◽  
Seismic Deformation

Tailings dam due to earthquake action may lead to severe slippage damage, and setting antiseismic measure is an effective method to prevent damage. Dynamic nonlinear finite element method is used in the efforts to analyze the earthquake reaction and the deformation characteristic. To reduce dam seismic deformation, the reinforcement effect of geotextiles, rock pressure and stone column is studied. Finally, a synthetically antiseismic measure that is composed of geotextiles-reinforced in sub-dam, rock pressure out of starter dam and densification foundation is proposed. It is found that the synthetically antiseismic measure produces better antiseismic effect, and offers a consult for the antiseismic design of tailings dam.

Small-Scaled Experimental Research on the Buckling of Steel Containment Under Axial Compression

2017 ◽  
Author(s):  
Pengfei Li ◽  
Fuquan Hu ◽  
Xuwei Wang ◽  
Zheng He ◽  
Zhi Gang
Keyword(s):  
Finite Element Method ◽  
Reference Value ◽  
Fem Analysis ◽  
Nonlinear Finite Element ◽  
Geometrical Parameters ◽  
Nonlinear Finite Element Method ◽  
Arc Length ◽  
Axial Pressure ◽  
Elastoplastic Constitutive Model ◽  
Shape Imperfection

Focusing on the general and localized elastoplastic buckling of the cylindrical section of steel containment under axial pressure, nonlinear finite element method (FEM) and small-scaled experiments are applied to analysis. First, FEM analysis is conducted considering nonlinear items caused by geometric shape imperfection and elastoplastic constitutive model by the arc-length method RIKS procedure. Parameter sensitivity of the buckling is revealed. Then, small-scaled experiments are carried out. Buckles status is observed, and key geometrical parameters’ influence are found. The results show that cylindrical buckling under axial pressure is sensitive to geometrical parameters and imperfection. It is necessary to employ more realistic parameters to the FEM analysis via accurate geometrical measurement. This research has reference value for the design and fabrication of AP series steel containment vessel.

Relevance of Mesh Dimension Optimization, Geometry Simplification and Discretization Accuracy in the Study of Mechanical Behaviour of Bare Metal Stents

2011 ◽  
Vol 2 (1) ◽  
pp. 1-15
Author(s):  
Mariacristina Gagliardi
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Degrees Of Freedom ◽  
Bare Metal Stents ◽  
Nonlinear Finite Element ◽  
Metal Stents ◽  
Bare Metal ◽  
Nonlinear Finite Element Method ◽  
Convergence Test ◽  
Geometry Simplification

In this paper, the authors propose a set of analyses on the deployment of coronary stents by using a nonlinear finite element method. The goal is to propose a convergence test able to select the appropriate mesh dimension and a methodology to perform the simplification of structures composed of cyclically repeated units to reduce the number of degrees of freedom and the analysis run time. A systematic study, based on the analysis of seven meshes for each model, was performed, gradually reducing the element dimension. In addition, geometric models were simplified considering symmetries; adequate boundary conditions were applied and verified based on the results obtained from the analysis of the whole model.

Cause Analysis on the Cracks in Concrete Plate of Canal Lining

2013 ◽  
Vol 405-408 ◽  
pp. 2596-2599 ◽  
Author(s):  
Jian Hua Cui ◽  
Zhi Qiang Xie ◽  
Han Jiang Xiao
Keyword(s):  
Finite Element Method ◽  
Nonlinear Finite Element ◽  
Nonlinear Finite Element Method ◽  
Foundation Soil ◽  
Cause Analysis ◽  
Construction Period ◽  
Concrete Plate ◽  
Operation Period ◽  
External Loads

Concrete cracks often appear in construction period and operation period of the canal lining. For analyzing the cause of these cracks, the factors which will cause cracks are classified based on the data collected. Also sensitivity analysis on these factors is carried out with 3D contact nonlinear finite element method. The result shows that, the factors which resulting in concrete cracks are temperature variation, humidity, uneven settlement of foundation, expansion deformation of foundation soil, external loads etc.; Joint-cutting should be done as soon as possible, expansive property of the foundation soil and construction quality of canal lining should be strictly controlled.

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