Stress Analysis of Dongjiang Arch dam by Finite Element Method under Different Concrete Elastic Modulus and High-Low Temperature Seasons

2016 ◽  
Vol 851 ◽  
pp. 780-784
Author(s):  
Wei Ping Tang ◽  
Jun Zhang ◽  
Hai Ping Tian

Elastic modulus and temperature are the main influences of dam stress. In order to study the Dongjiang dam stress for crack controlling, the critical parts stress of dam under different elastic modulus and high-low temperature seasons is analyzed by the finite element method. The results show that: (1) the arch crown and abutment principal tensile stress at upstream face and principal compressive stress at downstream face under high temperature season are greater than the calculation results under low temperature season for the whole at the normal storage water level; (2) the influence on stress caused by elastic modulus are more significant under high temperature season compared to low temperature season at arch crown and abutment, the maximum stress increase with the increasing of elastic modulus. (3) Dongjiang arch dam should pay more attention to the safety control under high temperature season and surface crack prevention and control work in low temperature season.

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Chenfei Shao ◽  
Chongshi Gu ◽  
Zhenzhu Meng ◽  
Yating Hu

Both numerical simulations and data-driven methods have been applied in dam’s displacement modeling. For monitored displacement data-driven methods, the physical mechanism and structural correlations were rarely discussed. In order to take the spatial and temporal correlations among all monitoring points into account, we took the first step toward integrating the finite element method into a data-driven model. As the data-driven method, we selected the random coefficient model, which can make each explanatory variable coefficient of all monitoring points following one or several normal distributions. In this way, explanatory variables are constrained. Another contribution of the proposed model is that the actual elastic modulus at each monitoring point can be back-calculated. Moreover, with a Lagrange polynomial interpolation, we can obtain the distribution field of elastic modulus, rather than gaining one value for the whole dam in previous studies. The proposed model was validated by a case study of the concrete arch dam in Jinping-I hydropower station. It has a better prediction precision than the random coefficient model without the finite element method.


Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3788 ◽  
Author(s):  
Yao ◽  
Lv ◽  
Zhang ◽  
Wang ◽  
Xie ◽  
...  

Precision glass molding is a revolutionary technology for achieving high precision and efficient manufacturing of glass aspheric lenses. The material properties of glass, including elastic modulus and viscosity, are highly dependent on temperature fluctuations. This paper aims to investigate the effect of elastic modulus on the high-temperature viscoelasticity of glass and the accuracy of the finite element simulation of the molding process for glass aspheric lenses. The high-temperature elastic modulus of D-ZK3L glass is experimentally measured and combined with the glass cylinder compression creep curve to calculate the high temperature viscoelasticity of D-ZK3L. Three groups of viscoelastic parameters are obtained. Based on this, the molding process of the molded aspheric lens is simulated by the nonlinear finite element method (FEM). The surface curves of lenses obtained by simulation and theoretical analyses are consistent. The simulation results obtained at different initial elastic modulus values indicate that the elastic modulus has a great influence on the precision of the FEM-based molding process of glass aspheric lenses.


1990 ◽  
Vol 112 (3) ◽  
pp. 266-272 ◽  
Author(s):  
H. Song ◽  
A. Moshaiov

The axisymmetric distortion in girth-welded pipes is studied in this paper. A model is developed based on the fact that only a small part of the pipe near the welding arc undergoes high temperature changes, and thus behaves thermo-elastic-plastically, while the rest of the structure is elastic in nature and may, at most, have some thermo-elastic effects. The model is shown to match Finite Element Method in predicting the overall approximated axisymmetric shrinkage in girth-welded pipes. A qualitative agreement with published analytical and experimental results is achieved as well.


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