Research On Design And Application Of Vibration Isolation System Of Floating Raft In Underwater Vehicle

Underwater vehicle is an intelligent system that can carry out underwater work.Underwater vehicle is also called "underwater robot".As a highly integrated and important equipment,the vibration and noise emitted by internal electromechanical equipment must be strictly isolated and controlled.With the support of the National Natural Science Foundation of China(51675306),the theoretical model of the floating raft vibration isolation system in the round cabin is constructed,and the influence trend of various physical parameters on the system vibration isolation effect is analyzed by numerical simulation.Under the actual engineering application background,the model of the vibration isolator is determined and carried out and the analysis of the dynamic characteristics of the vibration isolator was carried out.Based on above work,the raft frame of this floating raft vibration system was designed using the GB structural steel profiles.The underwater vehicle power cabin section is regarded as the overall structure,its dynamic characteristics are studied,and the engineering physical prototype of the floating raft vibration reduction system is trial-produced.After integration with the submersible power cabin section,the vibration isolation effect is tested experimentally.This study is an important guide for the design of floating raft vibration isolation systems for the underwater vehicle.The main research work of this paper can be summarized as follows:(1)A four-pole parameter method and substructure admittance method are used to model a typical floating raft vibration isolation system.The four-pole parameters and admittance matrix description of the machine,the upper and lower layers of the vibration isolator in the floating raft vibration isolation system,and the intermediate raft body are established.The sub-system synthesis method was used to assemble each subsystem,the expressions of force and velocity transmitted to the foundation were derived,and the vibration level difference was used as the vibration isolation evaluation index.The main parameters of the vibration isolation system to the system vibration transmission characteristics were studied.And the basis for the subsequent design of the floating raft vibration isolation system was laid.(2)According to the input parameters and design indicators in the project,the overall design plan of the floating raft vibration isolation system of the fuel cell in the underwater vehicle power cabin is given.Based on the analysis and comparison of the characteristics of various types of vibration isolators,the vibration isolator that meets the needs of this project is selected;the modal characteristics of the vibration isolator under the engineering background are simulated;the static compression deformation of the isolator is calculated;finally,the static and dynamic stiffness characteristics of the vibration isolator are analyzed.(3)According to the project requirements,the floating raft middle raft structure model was preliminarily designed,and the harmonic response analysis of the four different material combination raft structure was carried out.Further,in accordance with the relevant requirements of the GB Standard,a model of the raft frame engineering was designed using the structural steel profiles specified in the GB Standard and integrated with the vibration isolator,the vibration source equipment and the pressure-resistant chamber to form a power module section of this vehicle.Modal analysis and harmonic response analysis were carried out in the cabin model.The vibration level difference was used as the evaluation index of the vibration isolation performance of the floating raft isolation system.The simulation shows that the floating raft isolation system could achieve the vibration isolation effect of 59.7dB;The static characteristics of the underwater vehicle in stable operation,30° roll and 30°pitch conditions are mainly included,including the displacement and stress analysis in each state.Through analysis,it can be obtained that the overall power cabin section meets the statics index claim.(4)The engineering drawings of the floating raft frame were drawn and the engineering prototype was completed;the prototype was assembled;the prototype of the power module section was tested by the static deformation test of the isolator,and the compressive deformation of the upper isolator was 6.2mm,and the compressive deformation of the lower isolator was 8.3mm,and the compressive deformation of the isolators VD5 was within the allowable deformation range.Finally,an experimental test was conducted about the vibration isolation performance of floating raft vibration isolation system.The vibration level data information in the full frequency range is measured,and the vibration level difference is used as the evaluation index of the system's vibration isolation performance evaluation.The vibration isolation performance of floating raft vibration isolation system is analyzed and studied.After passing through the floating raft vibration isolation system,the average vibration level difference within 200 Hz can reach 38.8 dB,which meets the vibration isolation design requirements.