Simulation Analysis For Vibration Of Main Transmission System And Fuselage Under Maneuvering State

It is a special problem that the vibration of the whole Helicopter by the main vibration sourcewhich from the rotor, but at the same time, it is a very important problem. The vibration of theHelicopter reduces ride quality and deteriorates the environment of crew. and the long-term vibrationimpacts the working life of helicopter parts. According to statistics,60%of broken parts of helicoptercomes from main vibration source for rotor entirely or partly; at the same time, the result of vibrationincludes a high maintenance cost, which is double of the fixed-wing aircraft. So, it is very importantto analysis the vibration of the fuselage and the methods of vibration reduction at the process ofhelicopter development.In this paper, by means of an ultra-light helicopter, at first, analysis the dynamic helicopter rotorload as well as the abstract simplistic and decomposition of it, identified the boundary condition ofvibration simulation analysis of the helicopter system; secondly, the three-dimensional modal of theultra-light helicopter and the finite element modal of it will be established by means of UG andHyperWorks software, identified the support modal between fuselage and main gear box; thirdly, thetransfer function of fuselage system and vibration response under different mode were analyzed andcalculated, and the relationship of fuselage’s vibration and the natural frequency of support system ofmain reducer be identified; lastly, sensitive analysis has been done for support system of main reducerto decide the main factors which affect the natural frequency of support system, and dynamicoptimization for support system has been done to improve the structure of it, juxtapose the result ofvibration simulation between original FEM and optimized FEM.Result of analysis shows that optimization of support system makes sure that vibration levelswere reduced to a certain extant, and the quality performance is not been affected. The process ofsupport system optimization has important reference value on related design in this paper.