To avoid resonance, suppress the hull vibration and reduce the noise, vibration characteristics must be predicted during the process of design. The added water mass of the fishery administration ship is calculated for predicting accurately the vibration characteristics. The natural frequency of vertical and horizontal vibration are calculated by FEM method and empirical formula method. The natural vibration characteristics of the target ship under no-load and full-load condition are calculated respectively. The natural frequency of 1st vertical and horizontal vibration which calculated by FEM and calculated by the empirical formula are similar. The natural frequency of the no-load condition is lower than the full load condition.

In the process of modeling, ignoring the displacement of the pier directly replaced with fixed constraint, beam elements were adopted to simulate girder and pylon, and link elements were adopted to simulate the cable. The first ten order natural vibration mode and natural frequency were obtained, and the dynamic characteristics analysis of a single pylon cable-stayed bridge was discussed, which can provide certain reference and guidance for solving the problem of the cable-stayed bridge design.

In order to solve the problem of three-dimensional two medium transportation problems of fluid dynamics, the transportation principles of a metal ball moving in constant velocity fields were given. The space district was dispersed into some cuboid Euler cells in the directions of three coordinate axes, along which mediums were transported by turns. The continuous boundary condition was adopted to simulate infinite boundary. The interface reconstruction method in the mixture cells was the volume fractions method. The numerical simulation result indicates that the shape and size of the medium cuboid can keep unchanged basically during the medium transportation. The overspeed transportation problem of the volume fractions method in the course of transportation is pointed out. The research may provide certain reference and guidance for solving the multi-material fluid dynamics problems.