Numerical Study on the Thermal Fatigue of Cryogenic Vacuum Insulated Pipe

A vacuum insulated pipe used to transport LNG was exposed to repeated thermal loads at an extremely low temperature in order to study its thermal-fatigue lifetime. To prevent fatigue failure, the lifetime of vulnerable parts needs to be estimated beforehand; therefore, thermal stress and thermal deformation were first observed using thermal-structural coupling analysis. Based on the results, the structural safety of the vacuum insulated pipe was evaluated. Furthermore, fatigue life was evaluated according to the design parameters by applying the boundary condition of thermal fatigue analysis based on the results from the thermal-structural coupling analysis.