Dynamic equivalent design and realization of the pipeline of engine fuel pump accessory

The pipeline space configuration of fuel pump accessory is complex，and it is difficult to simulate directly in vibration environment test. In this paper，the system equivalent reduction expansion process（SEREP）is used for the dynamic equivalent design of the pipelines to meet the test requirements. By selecting the specific nodes on the pipeline as the main DOFs，and reducing the original pipeline model to the main DOFs model，the reduced mass and stiffness matrix are obtained. The sub-mode matrix is decomposed by SVD to further simplify the reduced mass and stiffness matrix，then the new reduced mass and stiffness matrixes of low-order pipeline model are obtained. The "mass ball-beam spring" structure model is proposed，which maps the reduced mass and stiffness matrices using "mass ball" and "beam spring" respectively，thereby determining equivalent design and processing parameters. Finally，the implementation of the equivalent design method is verified through examples，and the first frequency error between the equivalent pipeline and the original pipeline is mostly within 10%，meeting the requirements of engineering applications.