Structure Dynamics Modeling,Calculation And Response Optimization Of Carrier-Based Aircraft Landing

The carrier-based aircraft landing is a complex dynamics problem including many disciplines.Unlike the general land-based aircraft,carrier-based aircraft landing environment is more severe and dangerous.In order to ensure the operational capability of aircraft carriers,the process of carrier-based aircraft landing must be safe and efficient in the aircraft carrier.Hence,it is necessary to study the key technologies involved in the process of the carrier-based aircraft landing.This paper studies on the model reduction method considering the flexible fuselage,the parameters identification of the landing gear,the fluid-solid interaction analysis of the aircraft fuel tank and the optimal trajectory calculation based on structural dynamics theory,transient nonlinear finite element method,agent model technique and optimal control theory.The content can be listed below:(1)The model reduction method of aircraft landing dynamics has been researched.A hybrid-coordinate free-interface component mode synthesis method for local nonlinear system is proposed.According to the system characteristics,the structure is divided into linear component and nonlinear component.The equations of the linear component can be transformed into the modal coordinates by its linear vibration modes,while the equations of the nonlinear component are kept in the physical space.The synthesis equations can be deduced by combining the nonlinear component and the linear component together in terms of compatibility conditions at the interface.In order to improve the accuracy,the equivalent higher-order matrix is developed which makes the calculation of the residual flexibility matrix easier when the components have rigid-body freedom.In order to quantitatively describe the importance of each mode,a mode selection criterion method is proposed,and the lower order modes with large contribution are selected for modal synthesis.Finally,the validity of the method presented in this paper is verified by numerical examples,and the results show that the proposed method can improve the efficiency of the local nonlinear structure.(2)The method of parameters identification for landing gear is presented based on agent model technology.The mean square deviation of the time domain response of landing gear axial load is employed to formulate the objective function,and the surrogate model of the objective function is constructed by the RBF.Then the optimization algorithm is used to realize the parameter identification.Finally,two types of the parameters of the landing gear model are identified by numerical examples.The calculated results show that the proposed method has high accuracy.(3)The fluid-solid interaction dynamic model of aircraft fuel tank in the landing environment hasbeen developed.The ALE method is empolyed to establish the fluid-solid interaction model of the fuel tank of the aircraft.The simulation results show that the fuel movement in the fuel tank and reveal the influence of the different structure types of baffles on the impact load of the fuel tank was studied.This research provides an efficient simulation analysis method for anti-vibration design of aircraft fuel tank in the ship environment.(4)The problem of the optimal trajectory of carrier-based aircraft landing is presented.The dynamic model of the ideal arresting process without considering the kink-wave is established by taking the release rate of arresting cable as the control input.Based on keeping aircraft speeding up with uniform acceleration as longer as possible,a set of ideal trajectory is acquired by Gaussian pseudospectral method.The rigid-flexible coupling model of the carrier-based aircraft is established by the virtual prototyping technology,the effectiveness of the ideal trajectory is validated.The results show that the optimal trajectory can meet the design index of the acceleration of the aircraft.However,the effect of the kink-wave on the hook load is obvious at the initial period of the arresting process.