Mechanics Analysis Of A Novel Spherical Plain Bearing Tester

The new-type comprehensive fatigue tester of self-lubricating spherical plain bearing of the helicopter swashplate is a novel inner and outer ring nested mechanism referring to the real swashplate operating principle. Its designment will not only develop a new-type spherical plain bearing fatigue testing machine with compact structure and excellent performance, but also provide a useful model for analyzing the mechanical properties of swashplates and spherical plain bearings. The tester’s components parameters and related mechanical properties are mainly studied in this thesis.Firstly, the working principles and structural compositions of the tester and helicopter swashplate are contrasted, and the results show that tester can correctly simulate the movement patterns of self-lubricating spherical plain bearing and the mechanical characteristics of the pitch links. The position analysis of the tester’s air cylinder is carried out to establish their length and the vector equations.The blade pitch moment formula is educed from a kind of simple algorithm. With aerodynamic related formulas, the pitch link load in trimmed and sustained flight condition is calculated when the rotor advance ratio is 0.2. Thus the mechanical properties of the tester’s air cylinder are clearly fixed.Using ABAQUS software, the first 10 steps’ modal simulations of the assembly without inner ring in the different positions are carried out. According to the inherent frequencies and vibration types, several structure optimization opinions are proposed and the conclusion whether the inner ring’s rotation with frequently-used speeds will cause resonance can be drawn.Finally, the dynamic simulation is applied on the tester by using the multi-body system analysis function of ABAQUS software. Two patterns are simulated: the outer ring’s swing and the inner ring’s gradient rotation. Based on these data,the changing process of bearings contact stress is obtained and the mechanical properties of testing machine are evaluated.Based on the mechanical analysis of the machine, the related parameters of parts are obtained and the important reference data for the further optimization improvement are provided.