Finite Element Analysis of Thermal Mechanical Coupling for Buried Thermal Pipeline under Earthquake Action

Because the temperature of heat medium in the thermal pipeline is very high, which affects the pipe wall distortion and stress distribution, it is very important to analyze the thermal mechanical coupling in thermal pipeline. Numerical simulation of buried thermal pipeline damage under the earthquake action is analyzed by finite element method as basis of ADINA. Three-dimensional finite element modeling of buried thermal pipeline damage affected by site condition is investigated; geometry model is constructed with native and parasolid method in ADINA. The pipeline is modeled by native method and site is modeled by parasolid method, pipeline and soil are subtracted and merged by Boolean Operation. Gravity and earthquake force loads are defined in structure model, and temperature load in thermal model. In the structural model, pipeline is treated as thermoplastic material, and soil is treated as hot isotropic material. In thermal model, all materials are treated as heat conduction material. Thermal-mechanical coupling is calculated with the thermo-mechanical coupled analysis solver ADINA-TMC in ADINA. According to the calculating results of thermal-mechanical coupling, the damage of buried thermal pipeline is analyzed. Influence of single temperature load on the stress and strain of buried thermal pipeline is very small, but the stress and circumferential strain increase rapidly under earthquake action, especially, the axial strain is very complex. Under gravity and earthquake load, the temperature load mainly affects axial strain; the increasing temperature enables to reduce axial strain, which makes axial destruction reduced. Finally, some advice is proposed.