Fluid-strucure Intraction Analysis And Fatigue Life Prediction Of Aviation Elastic Thin-walled Fuel Tank

During the course of the voyage of aircraft,the flight attitude changes,the flight encountered unstable airflow,engine rotation imbalance and other causes will cause oil tank sloshing,so that the oil impact the fuel tank and thus make the fuel tank deformation.On the other hand,the deformation of the fuel tank will aggravate the sloshing of the oil,which called Fluid-Structrue interaction.The aircraft tank shaking will change the weight of the aircraft,affect the stability of the flight,and the impact of the liquid will make the structure of stress concentration,fatigue damage to the structure,greatly reducing the life of the fuel tank.At present,the study of liquid sloshing is mainly dependent on the higher cost test method.The numerical method is mainly based on the rigid body structure,and the influence of fluid-solid coupling is rarely considered.Therefore,it is important to study the fluid-structure interaction of the elastic thin-walled oil tank of aircraft.This paper uses the ALE(arbitrary Lagrange-euler)Finite element method to calculate and analyze the fluid-Structrue interactin problem of aircraft elastic thin-walled fuel tank.The ALE finite element method is used to establish the liquid sloshing control equation,and the discrete of the fluid domain and the solid domain is completed.In this paper,the ALE finite element method is used to study the sloshing of liquid in the water tank,and the results of the ale fem are compared with the test results in reference,which proves that the ALE finite element method is very accurate when applied to the liquid sloshing problem.Then,the Fluid-Structure interaction problem of liquid sloshing in a container is analyzed based on the elastic thin-walled fuel tank?cubic container and cylinder container.The comparison of the liquid sloshing characteristics between the elastomer container and the rigid body container shows the necessity of considering the fluid-solid interaction in the liquid sloshing problem.The comparison of the liquid sloshing characteristics between the cube container and the cylinder container shows the necessity of considering the shape of the oil tank in the fluid-solid coupling problem.After that,the fluid-structure interaction characteristics of the elastic thin-walled oil tank are analyzed deeply from the factors of liquid filling,shaking angle and shaking frequency.Finally,the fatigue life of the fuel tank is estimated according to the time domain curve of the dangerous position stress in the coupling analysis.