Study On Design Of Composite Hollow Deck Structures For Underframe Of The Maglev Train

Due to its light weight,high flexural stiffness and excellent longtitudinal properties and so on,the composite hollow deck structure has been widely used in the bridge engineering.In recent years,the maglev train designers aslo have paid their attention to this structure and have suggested to use this structure to design the underframe of maglev train for reducing the total weight.Therefore,a underframe of medium-low speed maglev train was designed with the composite hollow deck structure using the finite element analysis method in this paper.During the design processes,the longtitudinal compressive load and the uniformly contributed weight load were considered as the main loads which were subjected to the underframe and the deformation,the maximum stress ratio,the longtitudinal displacement and the vertical displacement were evaluated.In order to obtain a best structural configuration,six different composite hollow deck structures were analyzed and compared.After that,the structural parameters,mainly including the facesheet thickness,the core thickness and the ply angle of the best configuration structure were optimized.Finally,a scale-down composite hollow deck structural underframe was manufactured and tested.The main results and conclusions were shown as follows:Firstly,six different geometrical configurations(including triangle,isosceles trapezoid,right trapezoid,DuraSpan,rectangle and circle)of the composite core tube with same quantity and outline size were simulated and analyzed.By comparing the simulation values of the whole deformation,the maximum stress ratio,the longtitudinal displacement and the vertical displacement,it was found that the comprehensive properties of the rectangular core tube configuration are the best.And this configuration structure was selected to design and manufacture the underframe of maglev train.Secondly,the sensitivity analysis of the structural parameters,including the upper facesheet thickness,the bottom facesheet thickness,both of the upper and bottom facesheet ply angles and the rectangular tube core thickness,were conducted and then the value range of these parameters value were determined.After that,the rectangular configuration structure of the underframe of maglev train was optimized under the 350 kN longtitudinal compressive load.The result showed that the maximum longtitudinal displacement,bending deflection,stress ratio of the composite tube core and the composite facesheet are 0.52 mm,2.98 mm,0.499 and 0.278,respectively.Besides,the total weight of the underframe has been reduced by 26.85% compared with the alloy underframe.Finally,the manufacture process of the composite hollow deck structure underframe was studied.It is mainly consisted of two steps.The first step was fabricating the composite tube through the pultrusion process.The second step was moulding the perform and manufacturing the scale-down underframe component by using the vacuum infusion molding process(VIMP).And then,both of the composite tube and the scale-down underframe component were tested under the mechanical load.The results demonstrated that the longtitudinal compressive properties and flexural stiffness of the rectangular tube core composite hollow deck structure are very good.Therefore,the optimized configuration structure can satisfy the design requirements of the underframe of maglev train.