Structural Parameters Of Shipborne Helicopter Tail Drive Shaft Study On The Influence Of Vibration Characteristics

In order to improve the flight performance of shipborne helicopter and ensure its flight safety,China’s helicopter industry is developing towards the direction of low cost,low noise and low vibration.The structure of the tail drive system of shipborne helicopter is becoming more and more complex.All kinds of exciting forces and external maneuvering loads generated during flight will lead to obvious vibration of the tail drive system of helicopter.In serious cases,the tail drive shaft will break or even crash.Aiming at the above problems,this paper takes a certain helicopter tail drive system as the research object,constructs the finite element model of the tail drive system,carries out dynamic analysis and experimental test,and studies the influence of supporting structure parameters and shaft Angle parameters on the natural properties and vibration characteristics of the helicopter tail drive shaft.The main research contents of this paper are as follows:(1)The modeling principle of shipborne helicopter tail drive system is introduced,the dynamics equation of shipborne helicopter tail drive system is derived,and the finite element model of helicopter tail drive system is established based on the quantitative modeling method.The inherent characteristics of the stern drive system model of shipborne helicopter were analyzed,and the first three critical speeds and modes of vibration of the stern drive system were obtained.The analysis scope of the subsequent research was determined,which provided a theoretical basis for the influence of structural parameters on the vibration characteristics of the stern drive shaft of shipborne helicopter.(2)Based on the natural characteristics and response analysis of the stern drive system of shipborne helicopter,the influence of supporting structure parameters on the vibration characteristics of the stern drive shaft of shipborne helicopter is analyzed.By studying the vibration pattern diagram,bearing support reaction diagram and gear meshing force diagram of the tail drive system,it is found that the natural frequencies of the tail drive system of shipborne helicopter will increase with the increase of the support stiffness.With the decrease of the number of supports of the tail drive system,the span between the middle shaft of the horizontal drive shaft increases,its natural frequency decreases,and the mode participation coefficient increases.When the number of supports increases,the conclusion is opposite.(3)Based on actual helicopter tail drive system structure,according to the prin ciple of similar rotor design design the helicopter tail drive system simulation platform,design the experiment scheme,on the basis of the principle of force hammer experiment modal experiment was carried out,obtained the number of bearing rotor system in simulation test bench the influence law of critical speed and vibration mode,and compared the experimental test results with the results of the simulation analysis,The validity of the research method and the influence of structural parameters on the vibration characteristics of helicopter tail drive system is verified.(4)Aiming at the problem that the tail drive shaft vibration exceeds the standard and even breaks due to the deviation of tail drive shaft Angle of shipborne helicopter.With shaft Angle parameters of the tail drive system was deduced vibration equation,get the relationship between shaft Angle deviation and meshing stiffness,explores the deviation and tail inclined shaft vibration amplitude of the internal connection,reveals the tail shaft Angle parameters on the influence law of inclined shaft bending vibration properties,the results can be designed for the helicopter tail drive system dynamics and vibration fault analysis to provide the reference.