The Analysis of Temperature and Displacement Coupling in Freeze-Thaw Process of Soil

2011 ◽  
Vol 97-98 ◽  
pp. 192-198
Author(s):  
Shu Guang Hou

Through the coupling analysis of temperature and displacement fields in freeze-thaw process of soil by ABAQUS software, a numerical simulation method of the two fields coupling in freeze-thaw process of soil is put forward. In computation, the temperature field is analyzed firstly, and then the physico-mechanical parameters are defined as functions of temperature field. The geometric model and boundary conditions of numerical simulation are identical with these in laboratorial tests. By comparing the computation results of soil freeze-thaw process with its laboratorial test results, it was found that on the curve of soil freeze-thaw process obtained from laboratorial tests there is a short frost-swelling phenomenon at the initial stage of freeze-thaw process, and then is continuous thaw condition, but on the numerical computation curve, the reflect of soil frost swelling stage isn’t obvious. With the exception of this the numerical computation result and laboratorial test result are more identical. The frost-swelling quantum is very small, so the main expression of overall deformation of soil is thaw-settlement deformation. Therefore the frost swelling phenomenon doesn’t influence the end quantum of settlement. For this reason, the computing method introduced in this paper can be used to conduct numerical simulation of the thaw-settlement of frozen soil and to a certain extent guide the designs of subgrade and pavement in permafrost zones.

Author(s):  
Shaolin Chen ◽  
Hong Zhang ◽  
Liaoping Hu ◽  
Guangqing He ◽  
Fen Lei ◽  
...  

The fatigue life of turbine housing is an important index to measure the reliability of a radial turbocharger. The increase in turbine inlet temperatures in the last few years has resulted in a decrease in the fatigue life of turbine housing. A simulation method and experimental verification are required to predict the life of a turbine housing in the early design and development process precisely. The temperature field distribution of the turbine housing is calculated using the steady-state bidirectional coupled conjugate heat transfer method. Next, the temperature field results are considered as the boundary for calculating the turbine housing temperature and thermomechanical strain, and then, the thermomechanical strain of the turbine housing is determined. Infrared and digital image correlations are used to measure the turbine housing surface temperature and total thermomechanical strain. Compared to the numerical solution, the maximum temperature RMS (Root Mean Square) error of the monitoring point in the monitoring area is only 3.5%; the maximum strain RMS error reached 11%. Experimental results of temperature field test and strain measurement test show that the testing temperature and total strain results are approximately equal to the solution of the numerical simulation. Based on the comparison between the numerical calculation and experimental results, the numerical simulation and test results were found to be in good agreement. The experimental and simulation results of this method can be used as the temperature and strain (stress) boundaries for subsequent thermomechanical fatigue (TMF) simulation analysis of the turbine housing.


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Chaochao Zhang ◽  
Dongwei Li ◽  
Junhao Chen ◽  
Guanren Chen ◽  
Chang Yuan ◽  
...  

In this study, based on the background of massive freezing engineering in coastal strata, the thermal physical parameters and some freezing laws of soil were obtained through soil thermal physical tests and frozen soil frost heaving tests. When the freezing temperatures were −5°C, −10°C, −15°C, and −20°C, the frost heaving rates of the soil were 0.53%, 0.95%, 1.28%, and 1.41%, and the frost heaving forces of the soil were 0.37 MPa, 0.46 MPa, 0.59 MPa, and 0.74 MPa, respectively. In the range of test conditions, the frost heaving rate and the frost heaving force of the soil increased with the decrease of the freezing temperature, and the relationship was roughly linear with the temperature. The entire cooling process could be roughly divided into three stages: active freezing stage, attenuation cooling stage, and stability stage. The range of the frozen soil expansion did not increase linearly with the decrease of the freezing temperature, and there was a limit radius for the frozen soil expansion. A three-dimensional finite element model was established to simulate the temperature field and frost heaving of the soil under the on-site working conditions. The entire frost heaving process could be roughly divided into two stages. The calculated temperature values and the frost heaving force values were compared with the on-site measured values, and the results verified that the numerical calculation could accurately reflect the temperature field and frost heaving law of the formation.


2021 ◽  
Vol 233 ◽  
pp. 04046
Author(s):  
Changhao Zhang ◽  
Hu Li ◽  
Jianyu Yang ◽  
Huawei Lu ◽  
Peng Su

According to the structural characteristics of thin-walled parts, a model slicing method is proposed, and its mathematical process is established. The three-dimensional transient temperature field in the process of synchronous powder feeding laser cladding is studied and verified by numerical simulation method, and the thin-walled parts formed by later experimental processing are processed by the results of numerical simulation. Using the simulation results of temperature field as the basis for optimizing the processing parameters, the forming path of thin-walled parts is programmed and optimized, and the experimental verification shows the reliability of this method.


2013 ◽  
Vol 442 ◽  
pp. 342-345 ◽  
Author(s):  
Qiao Ling Wu ◽  
Yong Sheng ◽  
Feng Xie

Frost-heave and thaw-settlement of roadbed soil in highway will influence directly the durability, safe traffic flow and construction & maintenance costs in high-cold areas, therefore, recognizing and analysing the common embankment technologies of highway roadbed in high-cold areas accurately is significant to the effective controlling of project invest and the highway construction with limited funds in minority areas. The relations of Moisture Content and the freeze-thaw performances of roadbed fillers, subgrade soil were got respectively by experiments, and the results shows: Moisture Content has larger influence on the frost-heave and thaw-settlement performance of the soil. During the embankment of roadbed, the Moisture Content of fillers should be controlled nearby the optimum Moisture Content. The frost-heave and thaw-settlement occurs mainly in the subgrade soil, controlling the Moisture Content of subgrade soil is very important to improve the up-limit of frozen-soil, keep the stability of frozen-soil, control the thaw-settlement of roadbed and get rid of the roadbed diseases. CLC: U416.1 Document code: B


Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3397 ◽  
Author(s):  
Lan Xiong ◽  
Yonghui Chen ◽  
Yang Jiao ◽  
Jie Wang ◽  
Xiao Hu

The reliability and service life of power cables is closely related to the cable ampacity and temperature rise. Therefore, studying the temperature field distribution and the cable ampacity is helpful to improve the construction guidelines of cable manufacturers. Taking a 8.7/15 kV YJV 1 × 400 XLPE three-loop power cable as the research object, cable temperature is calculated by IEC-60287 thermal circuit method and numerical simulation method, respectively. The results show that the numerical simulation method is more in line with the actual measured temperature, and the relative error is only 0.32% compared with the actual measured temperature. The temperature field and air velocity field of cluster cables with different laying methods are analyzed by finite element method. The corresponding cable ampacity are calculated by secant method. The results show that when the cable is laid at the bottom of the cable trench, the cable current is 420 A, which is 87.5% of the regular laying. Under irregular laying mode, the temperature of cable is higher than that of regular laying mode and the cable ampacity is lower than that of regular laying mode. At the same time, a multiparameter online monitoring system is developed to online monitor the temperature, water level and smoke concentration of the cable.


2013 ◽  
Vol 631-632 ◽  
pp. 879-884 ◽  
Author(s):  
Shi Yao ◽  
Pan Guang ◽  
Huang Qiao Gao

Numerical simulation of flow field and flow noise was carried out on SUBOFF with Lighthill acoustical analogy and large eddy simulation method. The results agreed well with the numerical and experimental results obtained from published literature. The validation of the computational method of flow noise used in this paper was carried out. The geometric model was established for the unmanned underwater vehicle with full appendages and the flow field’s computational region discretization was carried out by using structural grid. Numerical simulation of flow noise for unmanned underwater vehicle with full appendages was taken. The numerical results show that the angle of attack has little effect on the flow noise level of the vehicle while the angle ranged from 0° to 4°. Compared with the “+”-type rudders, the flow noise level of the underwater vehicle with “X”-type rudders is about 3dB lower.


2019 ◽  
Vol 23 (Suppl. 3) ◽  
pp. 647-652 ◽  
Author(s):  
Yugui Yang ◽  
Mengke Liao ◽  
Haibing Cai ◽  
Peijian Chen

In this study, the temperature fields of frozen soil wall were calculated by using numerical method, and were analyzed after the soil was actively frozen with different freezing time. The results showed that the temperature field evolved from the freezing pipes, and then formed into frozen soil cylinders. After a certain freezing duration, the cylinders of frozen soil began to connect, and frozen soil walls started to form. At initial freezing stage, the thickness of frozen soil wall was mainly determined by the freezing pipes of the inner two circles. Then, connections were found to have occurred between the inner and outer frozen soil walls. Finally, the temperature fields of the unfrozen and frozen soils reached a state of stability. The results also showed that it was feasible to use numerical method to simulate the temperature fields of frozen soil walls during shaft sinking process, and potentially provided important references for the design and construction of deep alluvium shaft.


2019 ◽  
Vol 16 (03) ◽  
pp. 1842009 ◽  
Author(s):  
Wenxin Wang ◽  
Boyan Mao ◽  
Bao Li ◽  
Xi Zhao ◽  
Chensi Xu ◽  
...  

Instantaneous wave-free ratio (iFR), an invasive index of coronary artery tree, can evaluate the functional performance of vascular stenosis without pharmacological vasodilators. The noninvasive assessment of diameter stenosis (DS) obtained from coronary computed tomography angiography (CTA) has high false positive rate in contrast to iFR. The aim of this study was to develop a numerical simulation method that predicts the iFR and noninvasively assess the myocardial ischemia. Based on the CTA images, a patient-specific three-dimensional model of the aorta and coronary arteries were reconstructed. A stenosis was created in the left anterior descending artery (LAD) by reducing the DS of geometric model (40%, 50%, 60%, 75% and 90%). The patient-specific LPM boundary condition were set up to compute iFRct value during the wave-free period at the resting condition. The computed pressure and flow of coronary artery were realistic as compared to literature data. In contrast to invasive iFR, the iFRct can make a cost-benefit balance in terms of clinical cost and patient’s health.


2012 ◽  
Vol 501 ◽  
pp. 259-262
Author(s):  
Ze Peng Wang ◽  
Jia Na Ke ◽  
Lian Xiang Ma

Rolling resistance can impact on the fuel economy and dynamics of automobile. Numerical simulation can predict the rolling resistance and reduce the experimental cost. So, a simulation model was established base on ANSYS to compute the rolling resistance. Firstly, the 3D model finite element model of a radial tire was setup to solve the strain and stress of a rolling tire. Secondly ,the temperature field of tire was analyzed in line with the analytical result of the strain and stress. Thirdly, the rolling energy loss was calculated to solve the rolling resistance. The simulation method is conducive to the structural design of tire and computation or prediction of the rolling resistance of tire.


2013 ◽  
Vol 712-715 ◽  
pp. 1259-1262
Author(s):  
Jian Yu Cai ◽  
He Juan Chen

Analysis of numerical simulation was used on flow field and temperature field in mechanical seal cavity. It borrowed a new calculation method, which was more visual and simpler than before. And this method analysed the change in temperature field of mechanical seal ring and the distribution of temperature and pressure in the flow field when mechanical seal was working. The result showed that the numerical simulation method was effect to the flow field in centrifugal pump.


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