Design And Analysis Of The Crashworthiness Structure Of The Narrow Gauge Locomotive

With the rapid development of railway locomotive technology,passive safety of locomotives has become an important issue in current railway vehicle study and design.Carbody with good crashworthiness is an important way to improve the passive safety of railway vehicles.Locomotives can be classified into three kinds as per the gauges,i.e.standard,narrow,and wide.The standard gauge is 1435 mm,and that below 1435 mm is called narrow gauge.For locomotives with narrow gauge,its external dimensions are relative small due to the limit of the track gauge and vehicle gauge,which will accordingly limit the space sizes in designing on crashworthiness structure.In this paper,the narrow gauge diesel locomotive is taken as the object of study.Based on the Australian standard AS7520.1,the crashworthiness structure for narrow gauge diesel locomotive is designed and analyzed by using finite element analysis.Firstly,this paper introduces the research status and general design standard on crashworthiness both domestic and abroad.The design of the locomotive crashworthiness structure mainly focuses on two aspects: one is the monocoque type locomotive crashworthiness structure,which means the crashworthiness structure is integrated totally with the carbody structure,featuring reasonable strength,rigidity and good performance to transfer vertical force.Enough bearing capability is ensured for the cab's structure;the other is energy absorption structure,which means an energy absorption area composed of energy absorption parts for collision and deformation is placed at the end of locomotive.Such area can reduce the impact in collision as well as the deceleration speed so as to ensure the passenger survival space and the integrity of the locomotive structure.This locomotive is a kind of diesel locomotive.According to locomotive design standard requirements in AS7520.1,the crashworthiness structure strength is used to assess the performance of crashworthiness structure.Secondly,the locomotive adopts dual-cab and the load is carried by the underframe with no load carried by the mechanical room in the middle.That means the locomotive crashworthiness structure is the underframe and the cab.The major contacted components are anti-climbing device,collision post and corner post during the collision of underframe and cab.They are the most important structure in crashworthiness design.The underframe,cab,anti-climbing device,collision post and corner post are designed as per the locomotive carbody general layout,requirements of equipment arrangement functionality and locomotive crashworthiness.Thirdly,detailed calculation model on crashworthiness structure is established with finite element analysis software.Analysis and verification is carried out to locomotive crashworthiness as per the locomotive design standards under ten worse situations,such as underframe compression,underframe stretching,rescue,whole body lifting,side roll,cow-catch compression,anti-climbing device in longitudinal and in vertical,collision post,corner upright post,etc.The weak area in the original design are found out and improved.After improvement,the max allowable stresses of the crashworthiness structure are all less than the allowable stress.Strength requirements of locomotive crashworthiness structure are satisfied.The crashworthiness structure is proved reasonable for this narrow gauge diesel locomotive.Finally,after comparing with traditional locomotive crashworthiness structure on the basis of same criteria,it shows that this locomotive has a better static strength in crashwothiness structure.The structure designed is much more simple and compact.This paper can offer a reference for narrow gauge diesel locomotive in crashworthiness design.