Strength Analysis And Structural Optimization Of The Truck-like Landing Gear's Truck Beam

Landing gear is the main load-bearing part of the airplane, it is used for bearing corresponding load which the plane produces in taking off and landing or parking on the ground. It put forward higher requirements on the landing gear system with the development of large aircraft, it needs not only high strength and stiffness but also lightness. So analyzing landing gear truck system's strength and optimizing its construction have a vital practice meaning, which will effectively guidance new products design, it is an indispensable step in landing gear design.This paper introduces the elementary theory of finite element method and optimum design, the processes using ANSYS to carry out strength analysis and optimum design of Yun-8 nose landing gear's truck beam are introduced as a focal point.Firstly, this thesis uses the Ansys Parametric Design Language (APDL) which the ANSYS software provides, carries on the parametric finite element modeling to the truck beam according to the design drawings. The interaction between the truck beam and axle is simulated by the establishment of contact pairs in the installation of axle parts. This thesis discussed the options setting of contact analysis and its importance to confirm the reliability of the simulation. Discuss the way of equivalent the landing gear load to the loading point on the end of axle, the strength of the beam is validated by the stress distribution rule of the beam under six kinds of different operating modes obtained through the computation. Then, the simulation results are compared with theoretical calculation results to confirm the reliability of the simulation. Finally, in order to reduce the weight of the truck beam, In the process of optimization, selecting three main cross-section parameters as design variables, the stress and the deformation as state variables, the volume of the middle part of the beam was designated as objective function. The optimum results show that the volume of the middle part of the truck beam is reduced 23%of its volume, at the same time, the stiffness and intensity can meet the requirement, which reached to the purpose of reducing its weight and cost.