The Whole Process Simulation and Research on Temperature Field and Thermal Stress for Large Sluice Pier

2010 ◽  
Vol 163-167 ◽  
pp. 259-263 ◽  
Author(s):  
Hai Bo Wang ◽  
Sheng Qiang ◽  
Zhen Yang Zhu ◽  
Zhi Qiang Xie
Keyword(s):  
Temperature Field ◽  
Stress Field ◽  
Control Measures ◽  
Internal Cooling ◽  
3D Fem ◽  
Construction Period ◽  
Whole Process ◽  
Cooling Pipe ◽  
Field Environment ◽  
Temperature Filed

Based on the real construction process and field environment of large sluice pier for Caojie Project, considering the factors of surface insulation, internal cooling, the strength of the foundation and environmental climate, the basic theories of temperature field and stress field of concrete and 3D FEM combining with cooling pipe discrete model and iteration method are used to carry out the study of cracking mechanism. According to the 3D dynamic simulation of the temperature filed and stress field for the pier, reasonable temperature control measures are put forward for reference during construction period. The result of the simulation shows that the concept of the exterior thermal insulation and interior pipe cooling measures are of great useful in practice, and the methods should have great reference signification in future.

Simulation Analysis of Concrete Temperature and Stress of Plant Elbow Section of Sluice Dam

2011 ◽  
Vol 368-373 ◽  
pp. 3011-3014
Author(s):  
Shou Kai Chen ◽  
Li Xia Guo
Keyword(s):  
Concrete Structure ◽  
Thermal Field ◽  
Simulation Analysis ◽  
Fem Simulation ◽  
Element Model ◽  
Control Measures ◽  
3D Fem ◽  
Whole Process ◽  
Concrete Temperature ◽  
Complex Constraints

In view of concrete structure of dam plant elbows section is complex and strong external constraints, the study of concrete temperature and stress during construction should be carried out by computer simulation. A case of plant elbow section of a sluice dam project is presented where the 3D FEM simulation of instability thermal field and stress field of the concrete structure is adopted after building the 3D finite element model, and the changes and distribution characteristics of temperature and stress during whole process of construction is obtained. The results show that, under the complex constraints condition, the concrete of plant elbow section has greater tensile stress, it can lead to structural cracking, and it is necessary to take appropriate temperature control measures.

Real Time Temperature Simulation on Caohe River Aqueduct in South to North Water Transfer Project During Construction Period

2011 ◽  
Vol 255-260 ◽  
pp. 1270-1274 ◽  
Author(s):  
Ping Zhang ◽  
Bin Tian
Keyword(s):  
Temperature Field ◽  
Water Transfer ◽  
Maximum Temperature ◽  
Long Distance ◽  
Maximum Temperature Difference ◽  
Construction Period ◽  
Cracking Control ◽  
Temperature Filed ◽  
North Water ◽  
Emergency Water Supply

The cracking control standard of water delivery structure is quite strict especially for middle-route of south-to-north water transfer project with long distance water transfer, large discharge, the crack prevention standard is extraordinary strict and must be reached. Early crack during construction period will affect safe operation of aqueduct, and diurnal variation of air temperature has significant effect on temperature field of thin-walled structure. Construction process simulation and temperature filed calculation during construction period about Caohe river landing rectangle aqueduct of Beijing-Shijiazhuang emergency water supply engineering of middle-route of south-to-north water transfer project are carried out by FEM , and compared with the monitoring temperature. The comparison result shows that temperature field during construction can be accurately simulated by calculation, which is helpful for guiding construction and choosing construction scheme, and worthy to popularize to other similar projects. From the calculation and monitoring, the maximum temperature difference is less than the standard, so there will be no serous cracks during construction in Caohe river aqueduct.

A New Method for Improving the Stress Status of the Dam

2013 ◽  
Vol 444-445 ◽  
pp. 849-853
Author(s):  
Jian Hua Cui ◽  
Yong Feng Qi ◽  
Jie Su
Keyword(s):  
Temperature Control ◽  
Cooling Water ◽  
Control Measures ◽  
Sensitivity Analyses ◽  
Mass Concrete ◽  
Water Cooling ◽  
Concrete Gravity Dam ◽  
3D Fem ◽  
Construction Period ◽  
Operation Period

Under the action of annual change and sudden drop of air temperature, thermal induced cracking will occur in concrete dam during the operation period. For exploring the temperature control measures for crack prevention, taking a concrete gravity dam section as the research object, sensitivity analyses to the factors which affecting the water-cooling effect are conducted with 3D FEM, some significant suggestions for the water cooling are presented. The results show that, the stresses of the dam surface will decrease to a certain extent after water cooling in the operation period using the cooling water pipe which embedded during construction period, and the cracking risk of the dam will reduce. The study provides a new train of thought for the temperature control and crack prevention of the mass concrete during the operation period.

FEM Analysis of Massive Concrete Pile Using of Cooling Pipe in Shahe Bridge

2014 ◽  
Vol 501-504 ◽  
pp. 1359-1363
Author(s):  
Jian Cheng Sun ◽  
Ya Jing Pang ◽  
Wen Zhong Zhao
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Temperature Gradient ◽  
Stress Field ◽  
Water Temperature ◽  
Fem Analysis ◽  
Massive Concrete ◽  
Cooling Pipe ◽  
Concrete Pile ◽  
Element Theory

Based on finite element theory,Study on temperatrue field under the using of cooling pipe for massive concrete pile in shahe bridge by using MIDAS/CIVIL.Analysis of various factors effect to the temperature field, stress field and the temperature gradient of massive concrete pile,which included in inlet water temperature and the water flow, proposed the control indicators of cooling pipe design.

Analysis of the Atmospheric Temperature Stress on Mass Concrete by ANSYS Software

2011 ◽  
Vol 255-260 ◽  
pp. 3539-3542
Author(s):  
Pan Wu Li ◽  
Jia Ming Gao ◽  
Xian Zhe Zeng
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Stress Field ◽  
Crack Resistance ◽  
Temperature Stress ◽  
Atmospheric Temperature ◽  
Mass Concrete ◽  
Ansys Software ◽  
Construction Period

The heat(cold) caused by atmospheric temperature flows backward during construction period makes the temperature field and the stress field of concrete change a lot, and we have to take relevant measures when the change influence the crack resistance of concrete. Based on the causes and the change-principium of thermal stress, we use ANSYS software to analyze the influence on temperature field and the stress field of concrete that caused by atmospheric temperature, and find some measures to protect the concrete from excessive temperature stress.

scholarly journals Analysis and prediction of the coronavirus disease epidemic in China based on an individual-based model

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zuiyuan Guo ◽  
Dan Xiao
Keyword(s):  
Reproduction Number ◽  
Control Measures ◽  
Cumulative Number ◽  
Individual Based Model ◽  
Whole Process ◽  
Coordinate Descent Algorithm ◽  
Initial Stage ◽  
The Government ◽  
Prevention And Control Measures ◽  
And Control

AbstractWe established a stochastic individual-based model and simulated the whole process of occurrence, development, and control of the coronavirus disease epidemic and the infectors and patients leaving Hubei Province before the traffic was closed in China. Additionally, the basic reproduction number (R0) and number of infectors and patients who left Hubei were estimated using the coordinate descent algorithm. The median R0 at the initial stage of the epidemic was 4.97 (95% confidence interval [CI] 4.82–5.17). Before the traffic lockdown was implemented in Hubei, 2000 (95% CI 1982–2030) infectors and patients had left Hubei and traveled throughout the country. The model estimated that if the government had taken prevention and control measures 1 day later, the cumulative number of laboratory-confirmed patients in the whole country would have increased by 32.1%. If the lockdown of Hubei was imposed 1 day in advance, the cumulative number of laboratory-confirmed patients in other provinces would have decreased by 7.7%. The stochastic model could fit the officially issued data well and simulate the evolution process of the epidemic. The intervention measurements nationwide have effectively curbed the human-to-human transmission of severe acute respiratory syndrome coronavirus 2.

Investigation of the Constitutive Modle of Saturated Frozen Soil Based on Damage

2013 ◽  
Vol 353-356 ◽  
pp. 221-224
Author(s):  
Shuang Zhang ◽  
Chun An Tang ◽  
Lei Li ◽  
Shuai Li
Keyword(s):  
Phase Transition ◽  
Temperature Field ◽  
Stress Field ◽  
Constitutive Model ◽  
Internal Structure ◽  
Damage Mechanics ◽  
Frozen Soil ◽  
Unfrozen Water ◽  
Freezing And Thawing ◽  
Water Field

Saturated frozen soil is composed of soil, unfrozen water and ice, whose subgrade deformation is due to the weakened of internal structure which coursed by damage of the materials in the process of the cycle of freezing and thawing. Considing of the heterogeneity of saturated frozen soil and the phase transition between water and ice, and using of the damage mechanics theory, thermodynamics theory, filtration mechanics theory, a constitutive model of saturated frozen soil is setted up, which is of the coupfing problem of temperature field, water field and stress field. The rationality and validity of the model is verified by the experiment. It is also provided a new method for the study of frozen soil.

The Simulation of Temperature Field of 12Cr2Mo1R Ultra Thick Plate for Pressure Vessels during Heat Treatment by 3D-FEM

2014 ◽  
Vol 556-562 ◽  
pp. 472-475
Author(s):  
Yi Zhang ◽  
Guang Xu ◽  
Yue Yu ◽  
Hai Lin Yang ◽  
Ming Xing Zhou
Keyword(s):  
Heat Treatment ◽  
Temperature Field ◽  
Thick Plate ◽  
Pressure Vessels ◽  
Thickness Direction ◽  
Cooling Process ◽  
3D Fem ◽  
Treatment Technology ◽  
Quenching Temperature ◽  
Simulation Results

With ABAQUS software, a finite element model is built to simulate the temperature field of 150mm ultra thick plate for 12Cr2Mo1R pressure vessels during heat treatment. The simulation results show that the plate’s temperature between the surface and the core is difference during cooling process. Temperature difference is gradually increased with cooling process, then the temperature distribution of plate in the thickness direction becomes uniform. When quenching temperature is 910 °C and cooling medium is water, the microstructure at plate’s quarter in the thickness direction is bainite. Simulation results provide theoretical reference for determining heat treatment technology in industrial production of ultra thick plate.

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