Comparative study on two finite element models for multi-clamp pipeline system

Due to the limitations of space and environment, a considerable number pipelines supported by multiple clamps are used in the external pipeline system of aero engines, which lead to the modeling difficulties and low efficiency. In this paper, taking U-shaped and Z-shaped pipelines as examples, two methods of whole modeling and section modeling are used based on the finite element, and the piecewise linear models of clamps are introduced to compare the vibration characteristics under different boundary conditions. In addition, the simulation results are compared and verified by experiments. In the modal analysis, the coupled modes refer to the dependent modes which can influence each other through energy transfer while independent modes without energy transfer are called un-coupled modes. The results show that, for uncoupled modes of U-shaped and Z-shaped pipeline systems, the section model has smaller error and higher efficiency, which is suitable for the primary design stage of complex multi-clamp pipeline system. For the order of coupled mode, the accuracy of the whole model is high, and it is suitable for the check and vibration analysis of pipeline system. Moreover, the errors of both models decrease with the increase of tightening torque.