Structure Analysis And Optimization Of Tail Rotor Bearing Testing Machine

A very important part of a helicopter tail rotor system is a rod end joint bearing installed at both ends of a pitch rod,and its performance will directly affect flight.At present,testing machines that test the performance of this type of bearing can only simulate the single movement of a single bearing and cannot simulate all movements and loading performance of the actual working process.Therefore,predecessors designed a special tail rotor bearing tester for a certain type of helicopter,and the vibration performance that has a great influence on the test accuracy and the stress state of the core components must be analyzed.Therefore,this paper mainly studies the core components of the swing system,the complete machine frame and the loading system.The main research contents are as follows:The oscillating system is balanced and its dynamic performance is studied.Based on the method of adding balance mass,the system is improved;the inertial force and moment of inertia of the modified system are dynamically simulated and analyzed through ADAMS to obtain the change of force and moment;then the swing precision of the pendulum is studied and analyzed and judges whether the accuracy meets the design requirements.The results show that the inertial force and moment of inertia of the improved system are significantly reduced,and its swing accuracy is also satisfactory.Based on the fatigue life of the pendulum,it is optimized.Firstly,transient stress analysis is used to determine the presence of stress concentration.Based on this,fatigue analysis is performed to obtain the dangerous part of the pendulum.The structural dimensions of the pendulum rod are optimally designed by orthogonal test,and the optimal structure size of the pendulum is obtained.The structure of the entire machine frame is optimized.Using ANSYS Workbench for static analysis and modal analysis,the distribution of stress and strain as well as its natural frequency and mode shape performance are obtained.To reduce the vibration of the frame,topology optimization is performed on the basis of static analysis to find a satisfied structural form.The static and dynamic characteristics of the core components of the loading system are analyzed by using ANSYS Workbench.Then the corresponding stress and strain conditions as well as the natural frequency and mode shape are obtained,and resonance is avoided.