Optimization Design Of Double Layer Vibration Isolation For Diesel Generator

Diesel engine vibration device at home and abroad on the isolation system analysis in favour of car and ship power system,train vibration system with relatively small generator power pack as the locomotive power device in the car suspension,the vibration of diesel generator for the security and comfort of the train and the service life of the unit is not can be ignored,referring to the related literature and research results,for a certain type of train power package for double isolation design,the focus is through the optimization algorithm to determine the reasonable isolator stiffness value.In this paper,the vibration isolation system is a diesel generator set,which is connected with the common frame by 4 primary rubber isolators.The common frame is connected with the chassis of the car body by 6 rubber isolators.In order to improve the efficiency of analysis and calculation,the calculation accuracy under the premise of ensuring,on the model of mechanical system is simplified,the unit and the public architecture are simplified as vibration mechanical model of twelve degrees of freedom,and nod and roll motion.Derived from the system of twelve degree of freedom differential equations,based on the analysis of the response analysis unit and public architecture in order to make the system parameters,excitation frequency and system resonance,resonance unit and frame,and the system can achieve the ideal value of amplitude,the optimum range of frequency ratio is ?1>,?2<1;In order to avoid the resonance zone and the amplitude response,the ideal value of the amplitude response can be obtained,the optimum damping ratio range is0.15<?1<0.2,0.2<?2<0.25.The rate of expression through the system of force transfer differential equation is deduced,analysis of the isolator stiffness on the force transfer rate effect is:in the low-frequency part of the 0-10Hz with one level and two level longitudinal(X)increase the stiffness of the system,the force transfer rate is reduced,the natural frequency of the system increases,when the stiffness of the original stiffness the 3 times when the two level longitudinal stiffness(X)than a longitudinal(X)affect the stiffness of the system,the force transfer rate decreased quickly,increase the natural frequency of the system;a lateral stiffness(Y)and two transverse(Y)rate had no significant effect on stiffness the inherent frequency and force transfer;a vertical(Z)increase the stiffness of the system of force transfer rate has no obvious change,but the natural frequency of the system increases;with two vertical stiffness(Z)increase system force transfer rate increases,the vibration isolation performance variation,but the inherent system increased frequency.Comprehensive analysis shows that the vertical stiffness of the two stage isolator has the greatest influence on the force transfer rate of the system.According to the vibration isolator stiffness ratio between the group and the initial system isolator stiffness values,the force transfer rate as the optimization objective,the 10 isolator stiffness to three a total of 30 optimization variables,SQP optimization algorithm is used to obtain a set of optimization results.But because of a vibration isolation performance index can not reflect the vibration isolation performance,therefore this optimization results based on system vibration intensity as the optimization goal of re optimization,while using two kinds of optimization algorithms,GA and SQP results showed that two kinds of optimization algorithms in the system can meet the requirements of vibration intensity(less than 18mm/s above the normal working state),system of force transfer rate is more than 80%,calculate the inherent frequency of the system can avoid the incentive frequency corresponding to the rotating speed of the stiffness according to the optimization results,the system does not resonate.After the comparison of the various indexes,the GA algorithm is better than the SQP algorithm,which is based on the results of the objective function,the operation efficiency and the cost saving,and the final stiffness value is selected by the GA algorithm.