Three dimensional analysis of an arch dam abutment using a fracture damage model

The Generalized Finite Element Method (GFEM) is employed in this paper for the numerical analysis of three-dimensional solids under nonlinear behavior. A brief summary of the GFEM as well as a description of the formulation of the hexahedral element based on the proposed enrichment strategy are initially presented. Next, in order to introduce the nonlinear analysis of solids, two constitutive models are briefly reviewed: Lemaitre's model, in which damage and plasticity are coupled, and Mazars's damage model suitable for concrete under increased loading. Both models are employed in the framework of a nonlocal approach to ensure solution objectivity. In the numerical analyses carried out, a selective enrichment of approximation at regions of concern in the domain (mainly those with high strain and damage gradients) is exploited. Such a possibility makes the three-dimensional analysis less expensive and practicable since re-meshing resources, characteristic of h-adaptivity, can be minimized. Moreover, a combination of three-dimensional analysis and the selective enrichment presents a valuable good tool for a better description of both damage and plastic strain scatterings.

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Thermal Stress Analysis of Concrete Arch Dams Due to Environmental Action

Heat Transfer, Volume 2 ◽

10.1115/imece2004-60242 ◽

2004 ◽

Author(s):

Farrokh Sheibany ◽

Mohsen Ghaemian

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

Solar Radiation ◽

Dimensional Analysis ◽

Thermal Stresses ◽

Three Dimensional ◽

Arch Dam ◽

Downstream Face ◽

Element Analysis ◽

Arch Dams

A three-dimensional finite element analysis was carried out to determine the annual variation of temperature and thermal stresses of a concrete arch dam. Appropriate heat transfer boundary conditions in the dam body were used for air and reservoir temperature as well as solar radiation variations. Karaj arch dam in Iran was used as a case study. The rate of convergence of the numerical solution is examined. Results of the finite element analysis show that probable cracks occur in a very narrow region of the downstream face. Thermal loads have the most significant effects for causing downstream cracks in comparison with self-weigh and hydrostatic loads. The cracked areas of downstream face conform to the regions that have the highest temperature in downstream face. It can be associated to the solar radiation, which shows two-dimensional analysis of an arch dam cannot yields accurate results and three-dimensional analysis is necessary.

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Fracture-Damage Model for Anchored Discontinuous Jointed Rockmass and its Application

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.353-358.973 ◽

2007 ◽

Vol 353-358 ◽

pp. 973-976 ◽

Cited By ~ 1

Author(s):

Gang Wang ◽

Shu Cai Li ◽

Shu Gang Wang ◽

Jing Long Li ◽

Xiao Jing Li

Keyword(s):

Constitutive Relation ◽

Damage Mechanics ◽

Damage Model ◽

Three Dimensional ◽

Damage Mechanism ◽

Equivalent Strain ◽

Complex Stress ◽

The State ◽

Constructive Model ◽

Fracture Damage

According to the theories of fracture mechanics and damage mechanics, the constructive model and fracture damage mechanism of brittle discontinuous jointed rockmass are systematically studied under the state of complex stress in this paper. By the aid of the method of equivalent strain energy, the constitutive relation of anchored brittle discontinuous jointed rockmass is derived under the state of compression-shearing. The constitutive relation under the state of tension-shearing is also developed according to the theory of self-consistence. Finally, based on the above constructive models, the three-dimensional finite element procedure has been developed to model the ground movements that occur when underground power-houses of pumped-storage power station are installed in discontinuous jointed rockmass. The anchor supporting is an important component of this underground power-houses excavation work. Besides the displacement field and the secondary state of stress induced by the excavation disturbance, the effect of anchoring and the damage evolution around the power-houses have been particularly described during the process of installation. The numerical results obtained by numerical simulation were compared with that of field monitoring in order to verify the validity of the proposed models.

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In situ investigation of the primary recrystallization of alpha titanium in HVEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100110313 ◽

1978 ◽

Vol 36 (1) ◽

pp. 634-635

Author(s):

S. Naka ◽

R. Penelle ◽

R. Valle

Keyword(s):

Dimensional Analysis ◽

Texture Evolution ◽

Cold Work ◽

Three Dimensional ◽

Primary Recrystallization ◽

Thin Foils ◽

In Situ Investigation ◽

Grain Growth Model ◽

Alpha Titanium

The in situ experimentation technique in HVEM seems to be particularly suitable to clarify the processes involved in recrystallization. The material under investigation was unidirectionally cold-rolled titanium of commercial purity. The problem was approached in two different ways. The three-dimensional analysis of textures was used to describe the texture evolution during the primary recrystallization. Observations of bulk-annealed specimens or thin foils annealed in the microscope were also made in order to provide information concerning the mechanisms involved in the formation of new grains. In contrast to the already published work on titanium, this investigation takes into consideration different values of the cold-work ratio, the temperature and the annealing time.Two different models are commonly used to explain the recrystallization textures i.e. the selective grain growth model (Beck) or the oriented nucleation model (Burgers). The three-dimensional analysis of both the rolling and recrystallization textures was performed to identify the mechanismsl involved in the recrystallization of titanium.

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