Analysis Of Fluid Solid Interaction Characteristics Of Fuel Tank Bench Experiment

In recent years,with the rapid developm ent of the auto industry,the demand for the quality of the auto parts has been improved,and the increasing requirements of users and manufacturers are raised on the safety of the vehicle.In our country,the fuel tank is one of the most important auto parts which gove rned by compulsory standards and plays an important role in the safety of the vehicle.It can improve the safety performance and the life of the tank and ef fectively reduce the fuel tank bench experim ent times,which the statics analysis,the modal analysis,the fluid solid interaction characteristics of the fuel tank in the preliminary design of the fuel tank.The domestic and international development status of th e fuel tank was introduced and a brief overview about the fluid solid interaction in the the chapter 1.The m ain research contents of this paper are stated.In the chapter 2,the failure mode and failure mechanism of the metal fuel tank are introduced.The fuel tank bench experim ent requirements and the evaluation criteria of the fuel tank are introduced and the mechanism of vibration fatigue failure of fuel tank is analyzed.In the chapter 3,in order to obtain the m ore close to the actual bench experim ent data,according to the standard GB(18296-200 1)item 4.3,it's to verify the accuracy of the finite element analysis data which the two dif ferent boundary conditions of the tank for static analysis,transient analysis and the bench experiment of the fuel tank are carried out,respectively.It's show that the analys is of 3 degrees of freed om of the tank are constrainted,which the analysis data is more close to the bench experiment's data than the 3 degrees of freedom of the tank ar e constrainted for the dif ferent boundary conditions of the tank static analysis and transient analysis.In the chapter 4,Fo r the problem of abnormal noise and the fuel tank have a great shock by fuel oil shoshing when the spee d conversion and the road condition are poor.The modal analysis of the fuel tank can be carried out with the software Hypermesh and NX-Nastran and it was found that the first order frequenc y of the fuel tank in the area of dangerous area of natural frequency.The structure of the fuel tank baffle has been improved for enhance the anti-vibration capability of the fuel tank baffle,meanwhile,the overall structure of the fuel has not be altered.The m odal analysis and the frequency-sweeping test of the improved fuel tank was carried out.It shows that the first order frequency of the improved fuel tank is 54 Hz which it has been improved com pared the former and avoid dangerous area of na tural frequency,which is proved to be effective.Through the bench experiment of the fuel tank,it was found that the am plitude was large and the bottom was ruptured,which was caused by the resonance.Then the vibration frequency-sweeping experiment was carried out to get the natural frequency of the fuel tank.It was found that when loading half tank of water,the frequency of damped vibration was reduced.The natural frequency of th e fuel tank is obtained through the modal analysis by Hyper mesh and compared with the results of the fre quency-sweeping experiment.Three improved schemes of the bottom structure was proposed to change the natural frequency of the fuel tank.The vibr ation frequency-sweeping experiment of the improved fuel tank was carried out.It shows that the natural frequency is improved.For investigating the effect of half a ta nk of water on the fuel tank in the bench test,the paper is presented that the m odal analysis of fuel tank without w ater and the wet modal analysis with half a tank water were carried out use a finite elem ent software,respectively.The natural frequencies and vibration types of the fuel tank under the two conditions were obtained use software.And the experimental verification of the fuel tank through the frequency sweeping ex periment.The results show the m aximal displacement appeared on the baffle under the condition without water and the maximal displacement appeared on the bottom under the condition with half a tank of water.The first order natural frequencies of the fuel tank is reduced by 56.83% with the effect of the half a tank of water.