Study of the Volume Deformation and Stress Development of Concrete Influenced by the Different Cooling Rate

2015 ◽  
Vol 744-746 ◽  
pp. 1495-1498
Author(s):  
Yi Fang ◽  
Xue Feng Song ◽  
Long Chen
Keyword(s):  
Thermal Stress ◽  
Cooling Rate ◽  
Temperature Control ◽  
Control Measures ◽  
Stress And Strain ◽  
Stress Tests ◽  
Volume Deformation ◽  
Cooling Rates ◽  
Stress Development ◽  
Concrete Placement

This paper studied the development of stress and strain influences by different cooling rates based on the concrete thermal stress tests. furthermore, discussed the temperature control measures for early concrete placement.

The Influences of Different Temperature Histories on the Assessment of Cracking Resistance Based on the Concrete Thermal Stress Test

2014 ◽  
Vol 496-500 ◽  
pp. 2426-2430
Author(s):  
Xue Feng Song ◽  
Ying Fei Wang ◽  
Chao Li
Keyword(s):  
Thermal Stress ◽  
Temperature Control ◽  
Stress Test ◽  
Adiabatic Heating ◽  
Control Mode ◽  
Stress Tests ◽  
Cracking Resistance ◽  
Data Matching ◽  
Empirical Tests ◽  
Heating Mode

This paper studied the influences of different temperature histories on the assessment of cracking resistance based on the thermal stress tests, and also initially considered and discussed the effects of several empirical tests on thermal stress tests, including approximate adiabatic heating mode, temperature control mode, archived data matching mode, followed by some proposals regarding the standardizing research of thermal stress test of concrete.

The Effect of the Different Constraint Degree on the Temperature Stress and Strain of Concrete

2015 ◽  
Vol 727-728 ◽  
pp. 305-308
Author(s):  
Xue Feng Song ◽  
Zhi Hong Fan ◽  
Chao Li ◽  
Bao Lan Zhang
Keyword(s):  
Thermal Stress ◽  
Temperature Stress ◽  
Stress Test ◽  
Stress And Strain ◽  
Stress Tests

This paperstudied the development of stress and strain influences by different constraintdegree based on the concrete thermal stress tests. furthermore, suggested thevalue range of the constraint degree in the thermal stress test.

scholarly journals Effect of Hydration Heat Inhibitor on Thermal Stress of Hydraulic Structures with Different Thicknesses

2020 ◽  
Vol 2020 ◽  
pp. 1-17
Author(s):  
Wenqiang Xu ◽  
Sheng Qiang ◽  
Zhengkai Hu ◽  
Bingyong Ding ◽  
Bingyong Yang
Keyword(s):  
Thermal Stress ◽  
Stress Field ◽  
Tensile Stress ◽  
Temperature Control ◽  
Hydration Heat ◽  
Control Measures ◽  
Hydraulic Structures ◽  
Hydration Reaction ◽  
Early Hydration ◽  
External Temperature

Concrete hydration heat inhibitor can inhibit the early hydration reaction of concrete and reduce the initial heat release of concrete. However, there is no in-depth research on the effect of hydration heat inhibitor on hydraulic structures with different thicknesses and constraints. In this paper, numerical simulation is used to study the change of temperature and stress field after adding hydration heat inhibitor by establishing the finite element models of tunnel lining, sluice, and gravity dam. The results show that the effect of the hydration heat inhibitors on reducing the temperature peak is inversely proportional to the thickness of the structure. A formula is put forward to evaluate their relation in this paper. When the thickness of the structure is about 6 m, there is no peak cutting effect. For the stress field, hydration heat inhibitor can greatly reduce the thermal stress of the thin-walled structure and make the structure meet the temperature control requirements; for the medium wall thickness structure, it can reduce the internal tensile stress about 50% and the surface tensile stress about 20%, and other temperature control measures are still needed to ensure that the surface tensile stress of the structure meets the requirements; for hydraulic structures with large volume and thickness, the application effect of the inhibitor has limitations, which can reduce the internal tensile stress about 30%, but the tensile stress in the surface area will increase about 7% due to the increase of the internal and external temperature difference; therefore, other temperature control measures such as arranging cooling water pipe, strengthening surface insulation, and so on are needed to ensure that temperature cracks do not occur. This paper provides references and suggestions for the research and engineering application of hydration heat inhibitor.

CAE Simulation Study on Thermal Stress of Butterfly Valve and Actuator

2014 ◽  
Vol 532 ◽  
pp. 301-306
Author(s):  
Xiao Bo Tian ◽  
Jin Tang Yang ◽  
Dan Meng
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Temperature Control ◽  
Simulation Study ◽  
Hot Rolling ◽  
Control Measures ◽  
Butterfly Valve ◽  
Hot Air ◽  
Hot Rolled ◽  
Cae Simulation

To the valve system in the furnace hot air duct of the hot-rolled furnace in steel, the thermal Stress of butterfly valve and actuator was simulated by ANSYS. The feasibility of appropriate temperature control measures of too high temperature of butterfly valve and actuator was verified. And in the field, the transformation and the temperature measurement of butterfly valve and actuator were performed; the failure rate was calculated, to ensure that butterfly valve and actuator could meet the requirements of hot rolling.

scholarly journals Welding thermal stress diagrams as a means of assessing material proneness to residual stresses

2020 ◽  
Vol 56 (2) ◽  
pp. 1694-1712
Author(s):  
Andrii Mishchenko ◽  
Américo Scotti
Keyword(s):  
Thermal Stress ◽  
Cooling Rate ◽  
Thermal Stresses ◽  
Physical Simulation ◽  
Deformation Behaviour ◽  
Stress Generation ◽  
Cooling Rates ◽  
Wide Range ◽  
Quantitative Manner ◽  
Critical Regions

Abstract In this work, the proposal and appraisal of a method to describe in a quantitative manner the phenomenon of thermal stresses formation in welding at different heat-affected zone (HAZ) regions and under different cooling rates, by means of physical simulation, are explained. Under the denomination of welding thermal stress diagrams (WTSD), initially the concept and experimental arrangements needed to use the idea, based on a Gleeble simulator, are revealed. An approach to determine more realistic thermal cycles (peak temperature and heating/cooling rates) is introduced and applied. The method assessment was carried out by using specimens of a HSLA quenchable steel subjected to different cooling rates (covering a wide range of typical welding heat inputs) and peak temperatures (representing regions progressively farther away from the fusion line). The different thermal stress (TS) curves proved the concept based on the justification of the results. In addition, it was physically demonstrated that TS curves are governed mainly by two complex concurrent phenomena, namely contraction under restriction of heated areas and the expansibility of phase transformation. It was concluded that due to this balance, the highest residual stress (RS) does not occur either at slowest cooling rate or at fastest cooling rate. Nevertheless, the highest RS may not occur at the coarse grain zone either. TS progressively drops along the HAZ regions away from critical regions, and even at sub-critical regions there is tensile RS. Complementarily, it was also concluded that WTSD by physical simulation allows one to determine the deformation behaviour of a material as a function of temperature. This information can be used as input or calibration in modelling for thermal stress generation in steels.

Study on Temperature Field and Construction Monitoring of Hydration Heat of Railway Cable-Stayed Bridge Pile Cap

2011 ◽  
Vol 243-249 ◽  
pp. 1589-1596
Author(s):  
Xu Hui He ◽  
Hao Cheng ◽  
Hong Xi Qin
Keyword(s):  
Temperature Field ◽  
Thermal Stress ◽  
Temperature Control ◽  
Structural Reliability ◽  
Control Measure ◽  
Time History ◽  
Hydration Heat ◽  
Control Measures ◽  
Mass Concrete ◽  
Pile Cap

The temperature control of mass concrete is regarded to be a universal problem. Because of the heavy load of railway cable-stayed bridges, the pile caps usually have large dimensions, so the thermal stress, which is caused by hydration heat, must be emphasized. In order to study the spatial distribution of temperature in mass concrete and find a functional temperature control measure during construction, the theoretical and FEM analysis of hydration heat-thermal stress field are applied, which can improve structural reliability and provide reference for design and engineering of the similar project. Based on FEM calculation, the theoretical hydration heat temperature field is obtained. In the same time, the temperature sensors as well as strain sensors are arranged in the key position of pile cap. Then the variation of hydration temperature in concrete would be measured and recorded since the concrete is pouring. According to the theoretical simulation and the monitoring results, the time-history curve of hydration heat is obtained, and the variation of inner temperature gradient along the height direction as well as the longitudinal direction with the concrete age are studied, and the feasibility of temperature control measures is also verified.

Simulation of thermal stress and control measures for rock-filled concrete dam in high-altitude and cold regions

2021 ◽  
Vol 230 ◽  
pp. 111721
Author(s):  
Yuxiang Zhang ◽  
Jianwen Pan ◽  
Xinjian Sun ◽  
Jijun Feng ◽  
Dengqiang Sheng ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Altitude ◽  
Control Measures ◽  
Concrete Dam ◽  
Cold Regions ◽  
And Control

The effect of cooling rate on crystallization behavior and tensile properties of CF/PEEK composites

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Guangming Dai ◽  
Lihua Zhan ◽  
Chenglong Guan ◽  
Minghui Huang
Keyword(s):  
Cooling Rate ◽  
Crystallization Temperature ◽  
Crystallization Behavior ◽  
Crystalline Polymer ◽  
Scanning Calorimetry ◽  
Nonisothermal Crystallization ◽  
Cooling Rates ◽  
Control Range ◽  
Temperature Range ◽  
Transverse Tensile

Abstract In this study, the differential scanning calorimetry (DSC) tests were performed to measure the nonisothermal crystallization behavior of carbon fiber reinforced polyether ether ketone (CF/PEEK) composites under different cooling rates. The characteristic parameters of crystallization were obtained, and the nonisothermal crystallization model was established. The crystallization temperature range of the material at different cooling rates was predicted by the model. The unidirectional laminates were fabricated at different cooling rates in the crystallization temperature range. The results showed that the crystallization temperature range shifted to a lower temperature with the increase of cooling rate, the established nonisothermal crystallization model was consistent with the DSC test results. It is feasible to shorten the cooling control range from the whole process to the crystallization range. The crystallinity and transverse tensile strength declined significantly with the increase of the cooling rate in the crystallization temperature range. The research results provided theoretical support for the selection of cooling conditions and temperature control range, which could be applied to the thermoforming process of semi-crystalline polymer matrixed composites to improve the manufacturing efficiency.

scholarly journals Research on concrete temperature control measures in deep hole area of super high arch dam

2021 ◽  
Vol 826 (1) ◽  
pp. 012035
Author(s):  
Yuchen Fu ◽  
Yaosheng Tan ◽  
Chunfeng Liu ◽  
Lei Pei ◽  
Yajun Wang ◽  
...  
Keyword(s):  
Temperature Control ◽  
Arch Dam ◽  
Control Measures ◽  
Deep Hole ◽  
High Arch Dam ◽  
Hole Area ◽  
Concrete Temperature

Effects of RE on Critical Cooling Rate of Bearing-B Steel

2012 ◽  
Vol 535-537 ◽  
pp. 761-763 ◽  
Author(s):  
Yi Sheng Zhao ◽  
Xin Ming Zhang ◽  
Zhi Guo Gao
Keyword(s):  
Phase Change ◽  
Cooling Rate ◽  
Experimental Results ◽  
Cooling Rates ◽  
Critical Cooling Rate ◽  
The Law

The law of phase change of bearing-B steel during continual cooling was studied by adopting dilatometer. The CCT curves of bearing-B steel were drawn, and the effects of RE on critical cooling rates were studied. The experimental results show that the start temperatures of martensite TM was decreased from 438 to 404°C. The critical cooling rate was simultaneously decreased from 33 to 15°C/s.

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