scholarly journals Effect of Elastic Modulus on the Accuracy of the Finite Element Method in Simulating Precision Glass Molding

Materials ◽  
2019 ◽  
Vol 12 (22) ◽  
pp. 3788 ◽  
Author(s):  
Yao ◽  
Lv ◽  
Zhang ◽  
Wang ◽  
Xie ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
High Temperature ◽  
Great Influence ◽  
Molding Process ◽  
Glass Molding ◽  
Precision Glass Molding ◽  
Aspheric Lenses ◽  
Element Method

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.

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
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
High Temperature ◽  
Low Temperature ◽  
Arch Dam ◽  
Downstream Face ◽  
Safety Control ◽  
Principal Compressive Stress ◽  
Element Method

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.

scholarly journals Deformation Analysis of the Glass Preform in the Progress of Precision Glass Molding for Fabricating Chalcogenide Glass Diffractive Optics with the Finite Element Method

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1543
Author(s):  
Yue Liu ◽  
Yintian Xing ◽  
Hang Fu ◽  
Chuang Li ◽  
Chao Yang ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Surface Profile ◽  
Deformation Analysis ◽  
Deformation Model ◽  
Machining Parameters ◽  
The Finite Element Method ◽  
Glass Molding ◽  
Precision Glass Molding ◽  
Element Method

Precision glass molding (PGM) technology is a cost-efficient process for the production of micro/nanostructured glass components with complex surface geometries. The stress distribution, surface profile, and reduced refractive index of the molded lens are based on the lens being fully formed. The process of the deformation of the glass preform is rarely discussed, especially in the case of multi-machining parameters in the experiment. The finite element method (FEM) was adopted to analyze the glass preform deformation. Due to the phenomenon of incomplete deformation of the glass preforms in the experiments, two groups of finite element simulations with different boundary conditions were carried out with MSC.Marc software, to reveal the relationship between the deformation progress and the parameters settings. Based on the simulation results, a glass preform deformation model was established. The error between the model result and the simulation result was less than 0.16. The establishment method of the glass preform deformation model and the established model can be used as a reference in efficiently optimizing PGM processing parameters when the designed lens has two different base radii of curvature.

scholarly journals Integrating the Finite Element Method with a Data-Driven Approach for Dam Displacement Prediction

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Chenfei Shao ◽  
Chongshi Gu ◽  
Zhenzhu Meng ◽  
Yating Hu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Modulus ◽  
Random Coefficient ◽  
Arch Dam ◽  
Data Driven ◽  
The Finite Element Method ◽  
Random Coefficient Model ◽  
Proposed Model ◽  
Element Method

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.

scholarly journals Effect of the Directional Components of Earthquakes on the Seismic Behavior of an Unanchored Steel Tank

2020 ◽  
Vol 10 (16) ◽  
pp. 5489
Author(s):  
Rulin Zhang ◽  
Shili Chu ◽  
Kailai Sun ◽  
Zhongtao Zhang ◽  
Huaifeng Wang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Ground Motion ◽  
Seismic Behavior ◽  
Axial Stress ◽  
Ground Motions ◽  
Great Influence ◽  
Liquid Sloshing ◽  
Base Shear ◽  
Element Method

This paper investigates the effect of the multi-directional components of ground motion on an unanchored steel storage tank. Both the liquid sloshing effect and contact behavior between the foundation and tank are included in the study. A three-dimensional model for a foundation–structure–liquid system is numerically simulated using the finite element method. The Lagrange fluid finite element method (FEM) in ANSYS is used to consider the liquid–solid interaction. In the liquid–structure–foundation interaction model, the contact and target elements are adapted to simulate the nonlinear uplift and slip effects between the tank and the foundation. Three earthquake ground motions are selected for evaluating the seismic behavior of the tank. Comparisons are made on the horizontal displacement, “elephant-foot” deformation, stress, base shear and moment, sloshing of the liquid, uplift, as well as slip behavior under the application of the unidirectional, bi-directional and tri-directional components. Under the selected ground motions, the horizontal bi-directional seismic component has great influence on the liquid sloshing in the tank studied in this paper. The vertical seismic component produces high compressive axial stress, and it also makes the uplift and slide of the tank bottom increase significantly. The applicability of this conclusion should be carefully considered when applied to other types of ground motion inputs.

Modeling of Distortion in Girth-Welded Thin Pipes

1990 ◽  
Vol 112 (3) ◽  
pp. 266-272 ◽  
Author(s):  
H. Song ◽  
A. Moshaiov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
High Temperature ◽  
Qualitative Agreement ◽  
Experimental Results ◽  
Temperature Changes ◽  
Welding Arc ◽  
Element Method

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.

FEM Analysis on Thermal Stress of Desulphurization Injection Lance

2007 ◽  
Vol 336-338 ◽  
pp. 1531-1533
Author(s):  
Jian Qiang Qi ◽  
Yong Huang ◽  
Shi Xi Ouyang ◽  
Nan Li ◽  
Jiang Li ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Finite Element Method ◽  
Finite Element ◽  
Thermal Stress ◽  
Elastic Modulus ◽  
Fem Analysis ◽  
Finite Element Method Model ◽  
Method Model ◽  
Element Method

By means of a finite element method model, the effects of property parameters of refractory on thermal stress of injection lance have been studied. The results show that the maximum thermal stress increases with the improvement of thermal conductivity and elastic modulus of refractory, while it decreases at first and then increases with the improvement of the coefficient of expansion of refractory.

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