scholarly journals Seismic Optimization of Concrete Gravity Dams Using a Rubber Damper

2020 ◽  
Vol 25 (3) ◽  
pp. 425-435
Author(s):  
Majid Pasbani Khiavi ◽  
Mortaza Ali Ghorbani ◽  
Arash Ghaed Rahmati
Keyword(s):  
Hydrodynamic Pressure ◽  
Modeling And Analysis ◽  
Seismic Control ◽  
Isolation Layer ◽  
Control Functions ◽  
Concrete Gravity Dams ◽  
San Fernando ◽  
Major Factors ◽  
Element Technique ◽  
Rubber Damper

One of the major factors in an economic project of new concrete dams and safety valuation of available dams in seismic areas is the control and dissipation of the induced hydrodynamic pressure induced by dam and reservoir interaction. As one of the main control functions, dissipating the induced hydrodynamic pressure on the upstream face of the dam is considered in the evaluations. In this paper, the effects of a rubber damper as an isolation layer on the dam's seismic control have been investigated. For optimization of the rubber damper thickness and height, the Monte Carlo probabilistic analysis is used. The ANSYS program on the basis of finite element technique is applied for modeling and analysis. The Pine Flat dam in California, due to components of El Centro, San Fernando and North Ridge earthquake is modeled as a case study to evaluate the effect of upstream isolation layer on seismic control and optimization. The effect of the thickness and height of the rubber damper on reducing the responses is investigated and the optimum thickness and height are selected using sensitivity analysis for safe and economic design. The obtained results show the capability of the rubber damper in the seismic and hydrodynamic control of the sample model.

scholarly journals Study on the mechanism of water inrush in the arid western mining area

2019 ◽  
Vol 118 ◽  
pp. 03008
Author(s):  
Chao Zheng ◽  
Lan Yu ◽  
Jiangyi He ◽  
Fengfeng Yang ◽  
Jufeng Zhang
Keyword(s):  
Large Scale ◽  
Water Pressure ◽  
Water Inrush ◽  
Hydrodynamic Pressure ◽  
Mining Area ◽  
Mining Areas ◽  
Isolation Layer ◽  
Working Face ◽  
Combined Action ◽  
Tension Fracture

The analysis found that the coal mining process in the western mining area has the mining loss and disaster effect of the water-rich aquifer of the coal seam roof, which is mainly manifested by the overburden water in the roof. On this basis, the formation and development of the separation water of the roof is proposed, and the mechanism of the water inrush from the layer is revealed. It is found that there is hydrostatic pressure and hydrodynamic pressure in the separated water, under the combined action of bed separation water pressure, the mining-induced fracture and water-isolation layer tension fracture are connected, which causes water inrushing in the coal working face of the mine, and provides a theoretical guarantee for the large-scale development of coal resources in western mining areas.

Numerical Analysis of General Groove Geometry for Dry Gas Seals

2013 ◽  
Vol 457-458 ◽  
pp. 544-551
Author(s):  
Ji Bin Hu ◽  
Wen Jin Tao ◽  
Yi Min Zhao ◽  
Chao Wei
Keyword(s):  
Numerical Model ◽  
Hydrodynamic Pressure ◽  
Computational Domain ◽  
System Transformation ◽  
Modeling And Analysis ◽  
Gas Seals ◽  
Groove Seal ◽  
Shallow Groove ◽  
Regular Region ◽  
Volume Method

By Changing the key points on the spiral curve, general groove geometry was determined. Considering the simplicity of modeling and analysis, cubic spline function was used to express the general groove profile. By using the boundary fitted coordinate system transformation, irregular computational domain was transferred to regular region; Based on flow conservation principle, finite volume method was applied to discrete compressible Reynolds equation; By the application of Newton-Raphson iteration method for solving algebraic equation, numerical model of general groove dry gas seals was established. When compared sample results with shallow groove theory, the capacity and stiffness of numerical results match well with theoretical ones, verifying the accuracy of novel numerical model. Through analysis of three typical groove seals, spiral groove seal has strongest carrying capacity. Pressure distribution of three groove seals subjects to the law of hydrodynamic pressure effect. And the numerical model established in this paper will offer a general calculate platform for optimization of groove geometry in the future.

scholarly journals ANALYSIS OF ADHESIVELY BONDED SINGLE LAP RIVETED JOINT USING ANSYS

2014 ◽  
pp. 169-174
Author(s):  
KALE SURESH ◽  
K.L.N. MURTY ◽  
T.JAYANANDA KUMAR
Keyword(s):  
Life Time ◽  
Bond Line ◽  
Dissimilar Metals ◽  
Adhesively Bonded ◽  
Modeling And Analysis ◽  
Bond Line Thickness ◽  
Riveted Joints ◽  
Element Technique ◽  
Distribution Of Stress ◽  
Dissimilar Thickness

This project deals with the analysis of adhesively bonded single lap riveted joints. The present work involves the appropriate configuration and characterization of these joints for maximum utilization. The present study includes the effectiveness of bond line thickness, the bonded layer configuration. This is also applicable to dissimilar thickness joints, but in this project we have placed the adhesives at different places for riveted joints. The finite element technique was used throughout the analysis of present work. The present work showed that riveted bonded joints are superior in strengthening to the riveted joints. The riveted bonded joint seems to strengthen and balance the stress and distributed uniformly. This improves the efficiency and life time of the riveted joints; this is also applicable to dissimilar thickness and dissimilar metals joints for balancing, uniform distribution of stress and without any effect of corrosion on dissimilar metals. Modeling and analysis of adhesively bonded single riveted lap joint can be done by using ansys with a version of 13.0.

scholarly journals Boundary element modeling and analysis of adhesive bonded structural joints

2007 ◽  
Vol 4 (1) ◽  
Author(s):  
G. Cavallini ◽  
G. Davi ◽  
A. Milazzo
Keyword(s):  
Boundary Element ◽  
Anisotropic Elasticity ◽  
Stress And Strain ◽  
Bonded Joints ◽  
Strain Fields ◽  
Modeling And Analysis ◽  
Structural Joints ◽  
Element Technique ◽  
Good Agreement

In this paper, a boundary element technique for modeling and analysis of adhesive bonded structural joints is presented. The formulation is developed in the framework of the anisotropic elasticity and attention is focused on the application to composite structural joints built with the splicing concept technique. To model and analyze composite bonded joints a multidomain implementation of the boundary element method has been used. It has been proven well suited and very effective for the characterization of the mechanical behavior of spliced joints, allowing the analysis of the high gradient stress and strain fields near the splice lines as well as the prediction of the overall distribution of the interlaminar tractions. Numerical results show good agreement with analytical solution and finite element analyses.

scholarly journals Dynamic Stress and Displacement Fields on Concrete Gravity Dams due to Harmonic Ground Motion

2019 ◽  
Vol 8 (12) ◽  
pp. 3082-3089
Keyword(s):  
Boundary Conditions ◽  
Dynamic Stress ◽  
Hydrodynamic Pressure ◽  
Convergent Series ◽  
Upstream Face ◽  
Gravity Dams ◽  
Displacement Fields ◽  
Dynamic Displacement ◽  
Displacement Boundary ◽  
Concrete Gravity Dams

The partial differential equations (PDE) of equilibrium governing the natural vibrations of concrete gravity dams were derived in this work such that the fluid structure interactions were accounted for. The displacement formulation is a system of two coupled PDE in two unknown displacement components. For seismic ground motion assumed to be horizontal harmonic motion whose amplitude and period are known, the system of two coupled PDEs were solved subject to the boundary conditions using the method of undetermined parameters. In applying the method of undetermined parameters to the PDE, displacement shape functions constructed to satisfy the displacement boundary conditions were used in assuming the trial dynamic displacement fields in terms of two unknown parameters that were determined by substitution into the governing equations. Conditions for the trial dynamic displacement fields to be solutions to the governing PDE were sought by solving the resulting system of equations. The problem reduced to an algebraic eigenvalue eigenvector problem which was solved for nontrivial cases to obtain the characteristic frequency equation and the eigenvalues. Modal superposition technique was employed to obtain the general solution for the displacement fields. The use of the displacement boundary conditions at the upstream face and Fourier series theory yielded the dynamic displacement field components, and the dynamic stress fields. The maximum value of the hydrodynamic pressure distribution on the upstream face is found to occur at the bottom of the dam and is found mathematically to be a convergent series of infinite terms. The maximum hydrodynamic force was calculated by integration of the hydrodynamic pressure distribution over the upstream face of the dam, and found to be a convergent series. Values of the maximum hydrodynamic force computed in this work agree with solutions from the technical literature.

Parameters Influence of 150000m3 Base Isolation Storage Tank with Floating Roof

2012 ◽  
Vol 524-527 ◽  
pp. 1839-1843
Author(s):  
Ying Sun ◽  
Jian Gang Sun ◽  
Li Fu Cui
Keyword(s):  
Storage Tank ◽  
Base Isolation ◽  
Damping Ratio ◽  
Hydrodynamic Pressure ◽  
Seismic Excitation ◽  
Base Shear ◽  
Isolation Layer ◽  
Damping Rate ◽  
Overturning Moment ◽  
Isolation Period

Selecting 150000m3 storage tank as research object, the base isolation system was introduced and allowing for the impact of floating roof to study the seismic response of vertical storage tanks. The finite element models were established by using ADINA. The damping rate of floating-roof storage tank in multi-direction seismic excitation, and the damping rate of base isolation vertical storage tank in different isolation layer damping ratio, isolation periods were calculated respectively and comparative analyzed. The results indicate that: the damping rate of hydrodynamic pressure in three-dimensional seismic excitation is less than that of unidirectional, little change in the damping rate of base shear and overturning moment, sloshing wave height control action is not obvious. With the isolation period and isolation layer damping ratio increases, the damping rate of base shear, overturning moment, and hydrodynamic pressure are all increase. Isolation measures can not effectively control the sloshing wave height, and the isolation period and the isolation layer damping ratio have a reasonable optimization range.

Centrifuge Modeling and Analysis of Concrete Gravity Dams

1995 ◽  
Vol 121 (10) ◽  
pp. 1471-1479 ◽  
Author(s):  
Giovanni Plizzari ◽  
Fletcher Waggoner ◽  
Victor E. Saouma
Keyword(s):  
Centrifuge Modeling ◽  
Gravity Dams ◽  
Modeling And Analysis ◽  
Concrete Gravity Dams
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