Quantitative Analysis of Concrete Lining Damage in Field Canals by Frost Heave Using a Water–Heat–Mechanical Coupling Model

Author(s):  
Sen-Hao Cheng ◽  
Liang Wang ◽  
Bernard A. Engel ◽  
Yu-Bao Wang
2011 ◽  
Vol 361-363 ◽  
pp. 1922-1925
Author(s):  
Qing Zhang ◽  
Zhong Qiu Liu

Considering reinforced concrete lining often using in underground diversion tunnels as permeable media and combining concrete smeared cracking model, equivalent continuum porous saturated hydro-mechanical coupling model of lining is established based on generalized Biot’s theory. Reinforcement in concrete structures is typically provided by means of rebars which are embedded in the concrete. Then the model is applied to analyze lining structures of Jinping diversion tunnels during excavation and operation processes in which high external and internal water pressure would play a dominant role in affecting the behavior of lining respectively. Coupling research are carried out to analyze some important factors that would influence the hydro-mechanical behavior of lining and surrounding rock mass such as decreased orders of hydraulic conductivity magnitude of grouting zone, internal water pressure acting as body force and existing cracks in the lining, and the results shows that grouting zone of good quality and sufficient measurement for preventing the cracks from initiation and coalescence in the lining are important for the construction and operation of the diversion tunnels.


2013 ◽  
Vol 05 (04) ◽  
pp. 1350040 ◽  
Author(s):  
WENBIN ZHOU ◽  
FENG HAO ◽  
DAINING FANG

Poor cyclic performance of lithium-ion batteries is calling for efforts to study its capacity attenuation mechanism. The internal stress field produced in the lithium-ion battery during its charging and discharging process is a major factor for its capacity attenuation, research on it appears especially important. We established an electrochemical –mechanical coupling model with the consideration of the influence of elastic stiffening on diffusion for graphite anode materials. The results show that the inner stress field strongly depends on the lithium-ion concentration field, greater concentration gradients lead to greater stresses. The evolution of the stress field is similar to that of the concentration gradient but lags behind it, which shows hysteresis phenomenon. Elastic stiffening can lower the concentration gradient and increase elastic modulus, which are two major factors influencing the inner stress field. We conclude that the latter is more dominant compared to the former, and elastic stiffening acts to increasing the internal stress.


2014 ◽  
Vol 986-987 ◽  
pp. 823-827
Author(s):  
Qing Yuan Zheng ◽  
Min You Chen ◽  
Bing Gao ◽  
Nan Jiang

Reliability of IGBT power module is one of the biggest concerns regarding wind power system, which generates the non-uniform distribution of temperature and thermal stress. The effects of non-uniform distribution will cause failure of IGBT module. Therefore, analysis of thermal mechanical stress distribution is crucially important for investigation of IGBT failure mechanism. This paper uses FEM method to establish an electrical-thermal mechanical coupling model of IGBT power module. Firstly, thermal stress distribution of solder layer is studied under power cycling. Then, the effects of initial failure of solder layer on the characteristic of IGBT module is investigated. Experimental results indicate that the strain energy density and inelastic strain are higher which will reduce reliability and lifetime of power modules.


2014 ◽  
Vol 41 (6) ◽  
pp. 817-823 ◽  
Author(s):  
Hang WEN ◽  
Mian CHEN ◽  
Yan JIN ◽  
Kai WANG ◽  
Yang XIA ◽  
...  

2020 ◽  
pp. 2150002
Author(s):  
XIAOLI LI ◽  
LI CHEN ◽  
XIAOYAN LIU ◽  
YU ZHANG ◽  
LIFU CUI

The geological environment along a buried pipeline in permafrost regions is complex, where differential frost heave often occurs. To understand the changes in the stress behavior of pipeline structures caused by corrosion while laying them in permafrost regions, we established a thermo-mechanical coupling model of buried pipeline with corrosion defects by using finite element software. Numerical simulation analysis of buried pipeline was conducted. The effects of the frost heave length, the length of the transition section, the corrosion depth, and the corrosion length on the stress displacement were obtained. These analyses showed that the stresses and displacements of the pipeline with corrosion defects in permafrost regions can be simulated by using the finite element software numerical simulation method. Afterward, the corrosion resistances of pipelines with different corrosion lengths and depths were investigated via an electrochemical testing method. These results can provide some useful insights into the possible mechanical state of buried pipeline with regard to their design and construction, as well as some useful theoretical references for simulating real-time monitoring and safety analysis for their operation in permafrost regions.


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