Thermal-mechanical Coupled Finite Element Analysis For Buried Thermal Pipeline

With the rapid development of the urban central heat supply, the heating network is getting bigger and bigger, and the thermal pipes are also getting more and more. As the important component of the urban underground lifeline project, the thermal pipe network has some characteristics, including the high temperature of heat medium in the pipe, high pressure and so on. In addition, leakage accidents happened frequently, that threatened people's life and property's security seriously, polluted the environment, and caused serious resources waste. Therefore the thermal pipeline's breakage forecast has a very big social and the economical significance.The finite element analysis software ADINA is used for numerical simulation of the buried thermal pipeline damage under the external force. The controlling factors of the buried thermal pipeline damage is analyzed, the buried thermal pipe damage analysis of three-dimensional finite element modeling considering area changing is discussed, and the thermal-mechanical coupling in the calculation is considered importantly. In the construction process of three dimensional numerical models, two modeling ways-native and parasolid are used to complete the model. The pipeline and soil are merged by Boolean Operation. The pipeline is modeled by native while the site is modeled by parasolid. This can also make the element coordinated. We define the pipeline material for the thermoplastic material, the soil body as the hot isotropic material in the structural model's establishment process. The load considers separately the dead load, live load which including the seismic force load and so on. In the construction process of thermal modeling, the material is heat conduction material, and load is temperature load. In the circumstances of considering heat medium in the pipe, the paper analyzes the destruction situation of buried pipe under thermo-mechanical coupled effect with the thermo-mechanical coupled analysis solver ADINA-TMC in ADINA. Because the temperature of heat medium in the thermal pipeline is very high, it is influential to the pipe wall distortion and the stress distribution, so it is very important to analyze the coupling analysis between the heat flow and pipeline.The influence of the factors is analyzed according to the computing result, some conclusions are drawn: Under the influence of gravity, the temperature affects mainly axial strain and circumferential strain, makes axial destruction and circumferential destruction increased; under the role of gravity and seismic forces, the temperature affects mainly axial strain, and the increasing temperature enables to reduce the circumferential destruction.