For application of non-metallic material in efficient vibration isolation, the polymer materials are used to construct a ST (sleeve type) isolator. The outside parts of ST isolator are made of PLA material, and the inside parts of ST isolator are made of TPU material. The polymer material model is linear elastic and isotropic. The numerical model of the ST isolator is calculated by using the finite element method. The static analysis and vibration isolation performance are analyzed. The numerical results show that when the ST isolator is under a force of 20000 N in vertical direction, the maximun deformation is 0.80 mm and the maximum stress is 2.68×10⁷ Pa. When under a force of 5000 N in horizontal direction, the maximun deformation is 1.44 mm and the maximum stress is 3.70×10⁷ Pa. The natural frequency of ST isolator is higher than 1800 Hz, and the fixed frequency of ST isolator is higher than 560 Hz. The harmonic analysis and transient analysis results show that the ST isolator has an efficient vibration isolation performance, especially when the ST isolator is fixed on a rigid foundation. This 3D printed ST isolator can be used in next engineering application.

Abnormal vibration is one of the primary causes of high-pressure fuel pipe failure. To investigate the vibration characteristics of a high-pressure fuel pipe under combined diesel engine excitation and fuel pressure pulsation, a two-way fluid–structure interaction (FSI) model was established. A comparative analysis of the dry and wet modal characteristics was first performed. Based on the prescribed diesel engine vibration displacement, the vibration responses of the high-pressure fuel pipe with and without diesel engine excitation were compared. Furthermore, the effects of different engine loads (50 %, 75 %, and 100 %) and inlet pressure levels (36, 38, 40, 42, and 44 MPa) on the vibration energy distribution were investigated through spectral analysis. The results show that the natural frequencies of the high-pressure fuel pipe decrease under fluid-structure interaction, with the frequency reduction becoming more pronounced in higher-order modes. When diesel engine excitation is considered, the peak vibration displacement decreases slightly, while the vibration attenuation rate decreases, resulting in a longer vibration response duration. As the engine load increases, the vibration displacement increases, and the spectral components near the second and fourth wet modal frequencies become more pronounced under the full-load condition. Increasing the inlet pressure also leads to a progressive increase in the spectral amplitude, particularly near the fourth wet modal frequency. These findings provide theoretical support for vibration assessment and structural optimization of marine high-pressure fuel pipes.