Profile Design Of Rail Grinding Target For Curve Conditions

In recent years,domestic railways have shown a rapid development trend,with the increasing area of the road network and operating mileage,there are many small radius curves in the lines to adapt to the complex and changing geographical environment.When the train passes through a small radius curve,a large amount of lateral movement of the wheel pairs due to insufficient guiding capacity occurs,resulting in frequent contact between the wheel rims and the inside of the track and a large lateral movement range,which increases the vertical and internal wear of the track.In addition,the small radius curve at the track contact relationship is complex,the track surface is prone to induce fatigue cracks,peeling off blocks,wavy wear and other diseases,when the track wear changes the track contact relationship deterioration,it will aggravate the frequency and rate of the above-mentioned track diseases.Usually,the rail grinding method is used to remove the rail damage and repair the profile,for the curve working condition of the inner and outer rail load demand,respectively design and optimize the inner and outer rail profile to improve the rail contact relationship,can increase the train's curve through capacity,reduce the generation of rail damage.On the basis of comprehensive consideration of small radius curve conditions,the static and dynamic contact relationship between the tracks was studied,and the target profile of the inner and outer tracks was provided for the asymmetric grinding operation of the curve section,and improvement methods were provided to reduce the probability of disease in the curve section.(1)An asymmetric steel rail profile design method is proposed with the optimization goal of wheel track matching equivalent taper,a computational model for obtaining wheel track matching geometric parameters by the minimum distance search method is established,the basic principles of rail profile design and the optimization variables and their constraints are discussed,and a specific method for rail profile design optimization based on particle swarm optimization algorithm is given.(2)The optimized design of different tread profiles of inner and outer rails under post-wear curve conditions was carried out,and the geometric parameter matching relationship of the rails before and after optimization was analyzed in conjunction with LM-type wheel-to-heel comparison.The parameters such as the range of contact point distribution,rolling wheel diameter difference,equivalent taper,contact angle difference,etc.were compared,and the effectiveness of the profile optimization algorithm in improving the static geometric contact relationship of the rails was verified.(3)A vehicle dynamics model for asymmetric profile of a passenger car facing a curved section is built,and the method of setting the asymmetric inner and outer rail profile in a curved line is given.(4)Discussed the law of influence of post-wear rail profile optimization on the vehicle through dynamics performance,using the post-wear inner and outer rail profile optimization before and after as the simulation object,and comprehensively explored the change trend of transverse force,derailment coefficient,wheel weight loss rate,wear index and other parameters,and verified the improvement effect of the proposed profile optimization algorithm on vehicle dynamics performance.