| Subway is an indispensable means of transportation in every big city now.At present,the metro vehicles are developing towards the direction of fast speed and light weight,which puts forward higher requirements on the running stability and riding comfort of the vehicles.The improvement of running speed and the insufficient stiffness caused by the lightweight of the vehicle body will aggravate the coupling vibration between the vehicle body and on-board equipment and affect the running quality of the subway vehicles.At the same time,the active equipment such as transformer and air conditioner will generate its own excitation when working,which will also aggravate the vibration of the vehicle body.In this paper,the air conditioning and transformer which have great influence on the vibration of vehicle body are studied.Firstly,the rigid and flexible coupling dynamic model and multi-rigid body dynamic model of subway vehicle with on-board equipment were established by using the dynamics software UM and the finite element software ANSYS as the template of a certain type of metro vehicle intermediate vehicle,and the difference of the dynamic response of the two models under the linear and curved conditions was analyzed.The results show that the dynamic responses of the multi-rigid-body model and the rigid-flexible coupling model differ little in the curve condition,while the vertical stability and comfort values of the two models differ greatly in the linear condition.Then,the optimal Latin hypercube test design method was used to select the suspension parameter sample points of transformer and air conditioner,and the vehicle body vibration response value of each sample point was calculated by the um-isightl joint simulation platform.The response surface(RMS)approximate model is constructed according to the sample points and the corresponding response values of vehicle body vibration characteristics.After finishing the approximate model by using multi-objective optimization algorithm the NSGA-? optimization calculation,the approximation model to get the optimal parameter combination.The approximate model was optimized for a total of8,001 times,and the optimal dynamic response of the parameter combination obtained was as follows compared with the original parameter combination optimization: the root mean square value of vehicle front end vibration acceleration decreased by 17.75%(transverse)and14.69%(vertical),and the stability index decreased by 8.16%(transverse)and 4.19%(vertical).The root mean square value of vibration acceleration in the middle of vehicle body decreased by 23.25%(transverse)and 3.27%(vertical),and the stability index decreased by11.37%(transverse)and 0.29%(vertical).The root mean square value of vibration acceleration at the rear end of the vehicle body decreased by 15.35%(transverse)and 5.84%(vertical),and the stability index decreased by 6.96%(transverse)and 1.87%(vertical).Finally,according to the optimal suspension parameters,the structure of the corresponding vehicle equipment vibration isolation device is designed.Taking the air conditioning as an example,the initial structure of the air conditioning suspension bracket for installing the vibration isolation device is designed.On this basis,the fatigue life is taken as the constraint,and Optistruct software is used to optimize the topology of the suspension bracket by variable density method.After analysis,under the maximum longitudinal load after optimization,the maximum displacement of the support is 7.118×10-4mm and the maximum stress is 0.8365 Mpa.Under the maximum transverse load,the maximum displacement of the support is3.892×10-4mm and the maximum stress is 0.5673 Mpa.Under the maximum vertical load,the maximum displacement of the support is 5.442×10-5mm and the maximum stress is2.41 mpa.Under dynamic load,the minimum fatigue life of the support is 5×1019 stress cycles,which is far greater than the bottom line of 107 infinite life cycles,which meets the design requirements. |
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