Research On Crash Energy Management Of Crashworthy Vehicle Body Of Urban Train

With the continuous increase of running speed and passenger loads of passenger train in China,the crashworthiness of vehicle body structure has been widely concerned.The adoption of appropriate crash energy management(CEM)strategy in the design of vehicle body structure is the main measure to improve the crashworthiness of vehicle body structure.Thus,in order to further improve the crashworthiness of rail vehicle body,in this thesis,the CEM strategy of a urban train was researched,an endergonic process orderly and controllable CEM system was proposed,the methods to control vehicle structure deformation were studied,the variations of crash force and energy absorption under the scenarios ruled by AAR and EN15227 standard were analyzed.The above were completed by nonlinear finite element method and based on AAR S-034 and APTA SS-C standards.Establishing reasonable and accurate train FE model is the foundation of crashworthiness analysis for rail vehicles.In this paper,the spot-welding function of LS-DYNA was used to simulate the connection bolts between the traction device and the body pillow beam,the prepressure was added to the suspension system.In order to simulate rotary motion,the rotation pair was established between the wheelset and the axle box and the rotation angular velocity was applied to the wheelset.The influence of the method to control unloading on the “loading to unloading” process was researched when the additional energy-absorbing devices was modeled.An efficient pre-processing method for partial repetitive modeling is adopted to improve the efficiency of train collision modeling.Based on the AAR standard for the design of rail vehicle crash energy management,the CEM principles,requirements and implementation methods or approaches of rail vehicles were analyzed emphatically.Based on AAR standard,a kind of “honeycomb aluminum core-thin wall tube” composite graded energy absorption component was introduced.By comparing and analyzing the influence of different taper thin-wall tubes on the energy absorption process of crushing,a better combination of aluminum core-thin walled tube was obtained.The CEM systems of urban train cab structure and the intermediate vehicle end structure were designed respectively using the composite graded energy-absorbing component.By quasi-static crushing and vehicle-rigid crash scenarios to compare the deformation and energy absorption of the cab structure and the intermediate vehicle end structure before and after the installation of the CEM system.Research shows that the cab structure and the intermediate vehicle end structure adopted reasonable CEM system have a better crashworthiness.The collision deformation shape of the vehicle body is an important part of the safety design of the rail vehicle collision.Based on the principle of “pseudo-plastic hinge” and the requirements of AAR standard CEM design,the method to control the deformation of the main structure of the top cover,the bottom frame and the intermediate vehicle end is proposed.In this way,the longitudinal compression deformation shapes of the underframe,the top cover and the whole vehicle were studied.Then,the horizontal rollover deformation shapes were researched based on the ECE R66 standard.According to the scenarios of AAR standard and combined with the boundary conditions of the corresponding crash scenarios of EN15227,the variation of longitudinal force and interfacial energy distribution were studied when an 8 group urban train crashed a same static train and a single wegon respectively,which provided the theoretical basis for CEM design of new urban train body structure.