Optimization And Experimental Study Of Two-stage Vibration Isolation System

As one of the modes of transportation,diesel locomotive is widely used in less developed areas because of its excellent economy,safety and reliability,large output power,flexibility and convenience.The internal combustion engine is usually powered by a power package,and the vibration of the system is characterized by strong coupling,wide frequency band and multi vibration sources.The vibration of the vehicle will seriously affect the comfort of the passengers,and the double layer vibration isolation system is used to suppress the vibration.Due to the passive control of the traditional rubber isolator has been difficult to meet the requirements of the European and American countries on the light weight and vibration control of the internal combustion engine,new methods are urgently needed to solve the problem.Aiming at the typical vibration isolation system,the mechanical model of a two degree of freedom system under the action of the main exciting force is abstracted.The influence of vibration isolation parameters on the vibration intensity and transfer rate of the system is analyzed by the analytical method,and the basic vibration characteristics and vibration control strategy of double layer vibration isolation system are obtained.Then,the influence of vibration isolation system parameters(damping and stiffness)on the vibration isolation performance of the vibration isolation system is studied by the method of simulation analysis.The parameters of the vibration isolation system to be further improved and the degree and scope of the vibration isolation system are determined,and the parameter optimization scheme is formed.Based on the investigation of the existing vibration isolator and damper,the feasibility of the optimization scheme is studied.Finally,the optimal scheme is verified by using the double layer vibration isolation system.The results show that in order to reduce the dynamic reaction force obviously,the method of reducing the stiffness of the first stage and(or)the two stage isolator is necessary.Reduction of vibration intensity and stiffness will increase the low-frequency system startup and shutdown conditions and affect the stability of the system.The vertical stiffness of the first stage and the two stage vibration isolation system plays an important role in changing the directional characteristics of the toppling moment and the longitudinal and lateral stiffness of the isolator have little effect.When the damping is increased,the peak value of the directional mode resonance of the overturning moment becomes smaller,and the influence of the first stage isolator damping on the stability of the system is more obvious.The theoretical analysis and simulation results are combined with the feasibility of the project,and two vibration reduction schemes are formed.The first one is to replace the existing vibration isolator with the different vibration isolator with different parameters(smaller stiffness),and the passive vibration isolation system is equipped with the damper and the limiting device.The second one is the damper stiffness isolator under the condition with the parameters of vibration isolation system of semi active control method of adjustable damper.The experimental results show that the vibration isolation efficiency of the vibration isolation system is improved when the system is stable,and the vibration isolation efficiency of the vibration isolation system is obviously improved when the semi active vibration isolation system is used to ensure the stability of the system.The above conclusions have practical significance for the research and development of new vibration isolation system.It also has the universal reference value for the development of the double layer vibration isolation system.