Research On Dynamic Simulation And Optimization Of Damaged Aircraft Trailer

The damaged aircraft-trailer(DAT)is an important vehicle in the process of airport emergency rescue.In this paper,based on the mathematical model of 9-DOF(degree of freedom)DAT,the physical parameters of suspension and tire are taken into account.The relationships of the parameters of the suspension hydraulic components,the elastic force and damping force are established,the relationships of the tire stiffness,tire pressure and the speed of the tire are established,and then the optimization model of the whole vehicle is obtained.In order to reduce the secondary damage to the aircraft and minimize the vertical maximum acceleration of the DAT,the multi-island genetic algorithm is used to optimize the suspension system and tire.The main contents of the paper are as follows:1.The dynamic model of DAT is established.A random road model is established according to the requirements of emergency pavement,and a pulse road model is established according to the moving condition of the DAT.A schematic diagram of the structure of the DAT is set up,and the mathematical model of 9-DAT is set up according to the Lagrange equation,and the structure size parameters of the vehicle are determined.2.In the mathematical model of DAT,in order to obtain the relationship between the elastic force,damping force and component parameters of the suspension,the physical model of the hydraulic suspension is established.The main components,including the hydraulic cylinder,the accumulator,the damped hole and the one-way valve are selected and calculated,the nonlinear mathematical model of the suspension system is derived,and the different excitation of the suspension system is derived.The suspension hydraulic system is simulated under vibration frequency,and then the influence of component parameters of hydraulic suspension on stiffness characteristics and damping characteristics is analyzed.3.In order to obtain the stiffness of the DAT tire,the vertical stiffness characteristics of the tire are studied.According to the material model and nonlinear characteristics of tires,a finite element model of radial tire is established to simulate static mechanics and steady state rolling.The characteristics of tire static stiffness,tire vertical dynamic stiffness,tire pressure and vehicle speed are studied under different tire pressures.4.The overall vehicle dynamics simulation is carried out on the emergency road surface model and the pulse triangle road surface respectively,and the vertical acceleration curve of DAT is obtained.The key parameters affecting vehicle performance are selected based on Monte Carlo simulation.In order to reduce the secondary damage to the aircraft in the moving process,the optimization target is to minimize vertical maximum acceleration of DAT.The optimization is based on the multi-island genetic algorithm with the variables of the suspension hydraulic accumulator,the damping hole,the parameters of one-way valve and the tire stiffness parameters.Through optimization,a good matching of the suspension hydraulic system,tire physical parameters and vehicle performance is achieved.