Study on the Temperature Distribution Law of Thermoelastic Coupling Field in Concrete Pavement under Tunnel Fire

2014 ◽  
Vol 1065-1069 ◽  
pp. 716-720
Author(s):  
Zhong Shan Ren ◽  
Wo Wang ◽  
Lei Zhang ◽  
Xiong Lin ◽  
Pan Peng
Keyword(s):  
Temperature Field ◽  
Concrete Pavement ◽  
Hysteresis Phenomenon ◽  
Thermoelastic Coupling ◽  
Coupling Effects ◽  
Coupling Field ◽  
Material Parameters ◽  
Tunnel Fire ◽  
Single Temperature ◽  
Environment Temperature

Much research work about tunnel fire focused on a single temperature field of tunnel lining structures, and ignored the thermoelastic coupling effects in concrete pavement. Normally, the simplified heating curve sush as the environment temperature curve was adopted, therefore, a mathematical model of the thermoelastic coupling field was established based on finite element method, and the solving algorithm using finite difference method was proposed to analyze tunnel fire problem. Moreover, the results by the above method was also compared to those without considering thermoelastic coupling effects. In addition, the influences of material parameters, such as heat conductivity coefficient, specific heat capacity, elastic modulus and so on, were studied respectively to give the sensitivity of the problem. Through this research, the following conclusions were obtained: the thermoelastic coupling has a certain impact on the temperature field, and it appears the hysteresis phenomenon along the depth direction. Furthermore, when considering the thermoelastic coupling, the temperature of tunnel pavement under fire decreases with the increment of each material parameter respectively, i.e. all the material parameters have similar effects on the temperature field.

Dynamic thermoelastic coupling effects in a rod

AIAA Journal ◽  
1995 ◽  
Vol 33 (4) ◽  
pp. 776-778 ◽  
Author(s):  
Dan Givoli ◽  
Omri Rand
Keyword(s):  
Thermoelastic Coupling ◽  
Coupling Effects

scholarly journals Thermal Modeling and Calibration Method in Complex Temperature Field for Single-Axis Rotational Inertial Navigation System

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 384 ◽  
Author(s):  
Zihui Wang ◽  
Xianghong Cheng ◽  
Jingjing Du
Keyword(s):  
Temperature Field ◽  
Inertial Navigation ◽  
Calibration Method ◽  
Measurement Unit ◽  
Calibration Model ◽  
Navigation Systems ◽  
Moving Vehicle ◽  
Temperature Change Rate ◽  
Environment Temperature ◽  
Complex Temperature

Single-axis rotational inertial navigation systems (single-axis RINSs) are widely used in high-accuracy navigation because of their ability to restrain the horizontal axis errors of the inertial measurement unit (IMU). The IMU errors, especially the biases, should be constant during each rotation cycle that is to be modulated and restrained. However, the temperature field, consisting of the environment temperature and the power heating of single-axis RINS, affects the IMU performance and changes the biases over time. To improve the precision of single-axis RINS, the change of IMU biases caused by the temperature should be calibrated accurately. The traditional thermal calibration model consists of the temperature and temperature change rate, which does not reflect the complex temperature field of single-axis RINS. This paper proposed a multiple regression method with a temperature gradient in the model, and in order to describe the complex temperature field thoroughly, a BP neural network method is proposed with consideration of the coupled items of the temperature variables. Experiments show that the proposed methods outperform the traditional calibration method. The navigation accuracy of single-axis RINS can be improved by up to 47.41% in lab conditions and 65.11% in the moving vehicle experiment, respectively.

Thermal Image Analysis on the Axial Temperature Distribution of an AGHP (Axial Grooved Heat Pipe)

2009 ◽  
Author(s):  
Ling Cheng ◽  
Hanzhong Tao
Keyword(s):  
Temperature Field ◽  
Heat Pipe ◽  
Working Conditions ◽  
Wall Temperature ◽  
Flow Instability ◽  
Two Phase ◽  
Vacuum Degree ◽  
Single Temperature ◽  
Working Region ◽  
Vapor Liquid

The wall temperature field on the condenser section of an AGHP (Axial Grooved Heat Pipe) is measured by infrared thermal imaging technology, and the temperature field information on condenser wall is obtained in the horizontal and vertical working conditions and different temperature conditions. In accordance with the temperature field, Combination of the interaction characteristics between vapor-liquid two-phase annular flow, and by calculating, the accuracy to predict the outcome on non-condensable gas region is verified. Based on the distance to evaporator outlet, the condenser of the AGHP is divided into four regions for analysis. The zone I is closest to evaporator outlet and zone IV is located at the end of condenser. There are different characteristics in 4 zones for the AGHP with different vacuum degree and working conditions. On the conditions of horizontal working status, for the high vacuum AGHP, steadily working region, small fluctuations region, large fluctuations region and temperature recovery region will appear in turn. However for the low vacuum one, the single temperature fluctuation region and a linear decline region come forth followed by the abnormal increase region and steadily working region. Recurring to the analysis of wall temperature information, the characteristics of two-phase vapor-liquid phase change heat transfer and capillary driven flow inner the AGHPs can be discerned qualitatively or semi-quantitatively and some of the laws, Such as vacuum degree, two-phase flow instability are conjectured. The research content in this paper will redound to understanding inner working mechanism for an AGHP or a small heat pipe, and at the same time, provide theory evidences for heat pipe testing in the service of mass production.

Research on the Behavior of Rigid Pavement of Basalt Fiber Reinforced Dowel Bar under the Condition of Variable Temperature

2014 ◽  
Vol 587-589 ◽  
pp. 1209-1215
Author(s):  
Ya Ting Zhang ◽  
Chun Xiu Zhou ◽  
Zhi Yi Huang ◽  
Jin Chang Wang ◽  
Gang Bing Wu ◽  
...  
Keyword(s):  
Temperature Field ◽  
Bending Strength ◽  
Variable Temperature ◽  
Basalt Fiber ◽  
Concrete Pavement ◽  
Rigid Pavement ◽  
Cement Concrete Pavement ◽  
Lower Temperature ◽  
Concrete Face ◽  
Dowel Bar

This paper analyzed temperature field and temperature stress of cement concrete pavement under periodic variable low temperature using finite element method modeling technique in ABAQUS. And discussed the effect of wind speed, surface thermal conductivity coefficient on temperature field. Cracking and warping at the joint of concrete panel was simulated to analyze pavement deformation and mechanical characteristics. Results show that at lower temperature, concrete face will appear horizontal longitudinal displacement, causing the appearance of cracking; and warping effect will appear at the concrete panel, leading to concrete pavement void. It is revealed that dowel bar has not occurred plastic deformation, that is, bending strength meets the requirements.

Research on Sliding Layer of Cross-Tensioned Prestressed Concrete Pavement

2014 ◽  
Vol 1004-1005 ◽  
pp. 1486-1491
Author(s):  
De Chen ◽  
Sen Han ◽  
Cheng Ling ◽  
Dong Sheng Zhang ◽  
Fu Yang Guan
Keyword(s):  
Coefficient Of Friction ◽  
Prestressed Concrete ◽  
Concrete Pavement ◽  
Plastic Film ◽  
Analysis Method ◽  
Material Parameters ◽  
Friction Tester ◽  
Optimum Material ◽  
Stress And Deformation ◽  
Testing Speed

A coefficient of friction tester (CFT) for the cross-tensioned prestressed concrete pavement (CTCP) sliding layer was designed and developed basing on the Amonton law. The CFT can obtain precise values of the CTCP sliding layer coefficient of friction. Meanwhile, the sand and polyethylene plastic film (SPPF) sliding layer which has already been used in CTCP experimental road was tested using the CFT. The best testing speed (1mm/min) for CFT was obtained with applying regression analysis method to the results. The optimum material parameters for the SPPF are the combination of 2.6 fineness modulus of sand, 10mm thickness of sliding layer, and 3 μm thickness of polyethylene plastic film (PPF). The optimum materials combination of the SPPF provides minimum coefficient of friction to the CTCP sliding layer which can reduce the stress and deformation of the CTCP slab.

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