Parameter Sensitivity Analysis Of Mechanical Characteristics Of Air Rudders Based On Equivalent Stiffness Method

As an important part of aircraft guidance and attitude control system,air rudder system has gradually become a research hotspot in the field of aerospace in recent years.In the air rudder system,the bearings inside the transmission mechanism have strong contact and friction nonlinearity,which will have a greater impact on the mechanical characteristics of the air rudder.Therefore,in the design process of the air rudder structure,it is necessary to establish a suitable finite element model for analysis to determine the sensitivity of the mechanical characteristics of the structure to various design parameters.However,the nonlinear contact inside the structure will greatly reduce the calculation efficiency of the finite element analysis,and then affect the design process of the structure.Therefore,it is necessary to study an engineering calculation method to improve the calculation efficiency of the finite element analysis of the air rudder structure while meeting the error requirements.In this thesis,an air rudder structure is taken as the research object.By equating the deep groove ball bearing inside it,the calculation efficiency can be improved while ensuring the calculation accuracy.Studying the influence law of design parameters in the air rudder transmission mechanism on its mechanical performance has certain engineering application value to the structure design of the air rudder.This thesis mainly conducts the following researches:(1)In order to establish the equivalent stiffness model of deep groove ball bearing,the finite element analysis is carried out for deep groove ball bearing,the mechanical characteristics of deep groove ball bearing are studied,and the radial non-linear stiffness of deep groove ball bearing is obtained.The equivalent stiffness model of deep groove ball bearing is established by using Abaqus non-linear spring element,and the stiffness of the model is modified to reduce errors.Since the model does not consider excessive non-linear contact inside the bearing,the calculation efficiency of the model can be improved under the condition of ensuring the calculation accuracy.(2)Based on the equivalent stiffness model of the deep groove ball bearing,the stress and displacement characteristics of the air rudder were studied,and the parameter sensitivity analysis was carried out,the influence of the clearance,friction coefficient and material parameters of the internal transmission mechanism of the air rudder structure on the mechanical properties of the air rudder is determined.Studies have shown that the stiffness of the air rudder structure has the highest sensitivity to the material of the rudder shaft,the second is the sensitivity to the internal clearance of the transmission mechanism,and the least sensitivity to the friction coefficient.The clearance will make the dynamic response of the air rudder have obvious non-linear characteristics and affect the vibration amplitude of the air rudder.