Research On Optimization For Stainless Steel Carbody Structure Of DMU

With the rapid development of China’s rail transit equipment manufacturing industry and the continuous advancement of The Belt and Road Initiative,China’s rail vehicles are gradually moving to all over the world.Among all exported vehicles,the DMU with stainless steel carbody is recognized by most foreign users.Because it has a large number of advantages such as safety,speediness,low life cycle cost,operation without geographical restrictions and strong adaptability.What’s more,the exported DMU with stainless steel carbody can be optimized and improved according to the different standards of different countries.As a result,the production costs can be reduced and production efficiency will be improved significantly.First of all,this paper summarizes the development history and present situation of domestic and abroad DMU with stainless steel carbody.The development situation of structural optimization for stainless steel carbody is expounded.Subsequently,the basic theory of finite element method,modal analysis,super-element method are summarized briefly,and then the development history and mathematical model of the structural optimization design are also introduced.The research takes a certain kind of exported DMU with stainless steel carbody as the research object.After fully understanding its geometric characteristics,the finite element model of the carbody is established by Hyper Works to calculate its performance.The calculation results show that the strength,stiffness and modality of the carbody meet the requirements from relevant standards.But the distribution of stress is uneven and there are a large number of redundant solder joints,which indicate the carbody has a plenty of room for optimization.Finally,the side wall is optimized twice by using the Opti Struct solver.For the first time,all the 7mm diameter solder joints of the side wall are optimized by topology optimization.The super-element method based on static condensation can reduce the calculation time of the optimization process by 47.5%.Considering the factors of welding technology and welding appearance,the optimization results are improved manually.On the premise of ensuring the performance of the carbody,1190 redundant solder joints of the side wall are reduced,which accounting for 12.8% of the total solder joints.For the second time,the plate beam structures of the side wall are optimized by size optimization.With the super-element method based on dynamic condensation,the time of optimization process can be reduced by 67.4%.On the premise of ensuring the performance of the carbody,the mass of the side wall is reduced197.4kg,accounting for 8.7% of the side wall’s total mass.Obviously,it is a remarkable lightweight result.The decrease in the number of solder joints and the reduction in the mass of the carbody can directly improve the economic benefits of the factory.In conclusion,the efficient optimization processes and feasible optimization programs can provide valuable references for actual engineering applications.