Lever Vibration Isolator Design And Experiment Of Helicopter Engine

Helicopter vibration isolation has always been difficult in helicopter design.Excessive vibration levels can cause damage to the structure of helicopter,it may also affect the performance of airborne equipment,and increase the cost and workload of later maintenance.The transmission of engine vibration to the fuselage is one of the most important factors that affects the vibration level.Effective engine vibration control is a key issue in the design of helicopters.Therefore,it is necessary to add a vibration isolator between the fuselage and the engine to reduce the transmission of the exciting force to the fuselage.In this thesis,the dynamic model of the lever spring rubber vibration isolator is established firstly.The simulation program of the vibration isolation system is written by Matlab software.The vibration isolation effect of the vibration isolator and the parameters affecting the vibration isolation effect are analyzed.Secondly,the material properties and mathematical models of viscoelastic materials are analyzed.The stiffness characteristics of rubber mats are analyzed by empirical formula and finite element software modeling.Finally,springs,rubbers and components of the connection structure for the vibration isolator were designed,assembled and subjected to modal experiments and acceleration response experiments.The mode shape and frequency of the structure are obtained.The frequency response function of the model is compared with or without the spring and the damping structure to determine the effective vibration isolation frequency range of the isolator.Comparing the acceleration response of the model with or without the spring and damping structure,the results prove vibration capability of the isolation system.The installation of the isolator can effectively isolate the vertical vibration load.