Research on the vibration band gaps of isolators applied to ship hydraulic pipe supports based on the theory of phononic crystals

According to theory of phononic crystals (PCs), a ship hydraulic pipeline isolator with one-dimensional periodic composite structure is designed, which is composed of metal and rubber. The vibration of ship hydraulic pipeline can be suppressed by the band gaps (BGs) of the isolator. The band structure and frequency response function (FRF) of the isolator is figured out by the finite element method (FEM). To obtain the best frequency ranges and width of the BGs, the influences of various material, lattice constant and fineness ratio are considered, and the best structure parameters were also obtained. The results revealed that the isolator has axial vibration BGs with frequencies from 400 Hz to 10000 Hz, and the maximum vibration attenuation is up to 150 dB. The research provides a new technical method to control vibration of ship hydraulic pipeline.