Dynamic Response Analysis Of A Folding Rudder With Contact Nonlinearity

Folding rudder is widely used in aircraft due to its high space utilization.Because of the functional requirements of the folding mechanism,there are complex connections among the components of the folding rudder structure.These complex connections cause nonlinear contact problems in the structure,and typical nonlinear factors in contact problems,like clearance and friction,have significant influence on the dynamic characteristics of folded rudder.In this paper,the effects of various nonlinear factors on the dynamic response characteristics of the folded rudder are studied.In this paper,the finite element model of folded rudder is established.Considering that there are a lot of connection relationships in the structure,the contact relationship is only defined on the main connections locating on the load path,and the multi-point constraint method is used to simplify the unimportant connections.After meshing the structure,the material parameters of the structure and the connection stiffness of the fixture are modified by hammering test.In order to make the finite element model a close approximation to the physical model,researches on mesh independence and contact properties on the contact region are carried out,and subsequently,the modeling parameters are selected according to the results.The commercial software Abaqus is used to calculate the dynamic response of the folded rudder structure under the foundation excitation.The frequency error between the simulation results and the experimental results is less than 2%,which verifies the correctness of the finite element model.The effects of load magnitude,friction coefficient and clearance on the dynamic response characteristics of the folded rudder are further studied using the finite element model.Considering the simplified modeling requirements of the folded rudder structure,the finite element calculation program of the contact problem is compiled,which lays the foundation for the simplified modeling and calculation of the folded rudder structure.Finally,the three-dimensional contact between the shaft and the hole which is the typical contact problem of the structure is studied and the analytical relationship between the contact force and displacement and rotation angle is established based on the finite element simulation.