Study On The Relationship Between Buffer Characteristics And Locomotive Adhesion Under Starting And Braking Situation

With the rapid development of our economy,the demand for all kinds of materials is becoming more and more huge.As an economical and efficient transportation mode,heavy-haul railway has been widely concerned and developed in the world.For China,the construction of heavy-haul railway will greatly alleviate the unbalanced between supply and demand in domestic freight transportation.In the beginning,the development of heavy-haul transportation was largely solved by lengthening train marshalling and increasing axle load.However,many new problems have emerged with the growth of heavy-haul train marshalling and increasing of axle load,including coupler breakage,wheelset and track damage,derailment and insufficient infrastructure of the line.All of these problems will threaten the safety of train operation.Nowadays,many researchers concerned that promoting the efficiency of locomotive adhesion can not only increase the capacity of heavy-haul trains,but also ensure the stability of trains.To ensure the rapid and sound development of heavy-haul railway transportation,it is necessary to carry out some relevant simulation analysis on locomotive adhesion state.Based on the traditional model of wheel-rail coupling dynamics of single-section vehicles,this paper has considered the longitudinal dynamics of vehicles and the model of coupler buffer to establish a three-dimensional model of rail coupling dynamics of trains.The dynamic model is used to simulate the train under different line conditions and buffer characteristic parameters.In line condition,two kinds of lines are mainly selected: curve and vertical curve,and the characteristic parameters of buffer choose stiffness and damping.The state of wheel-rail adhesion of locomotive is simulated and analyzed based on different line conditions and buffer parameters.The results show that when the train starts or brakes on the curve,the wheel-rail adhesion will fluctuate greatly,and the smaller the radius of the curve,the greater the fluctuation,therefore,the curve with smaller radius should be avoided as far as conditions permit;When the train passes through the vertical curve,the adhesion state of the locomotive becomes worse with the increase of slope;The smaller the stiffness and damping of the buffer under the starting condition of the train,the average value of the locomotive adhesion coefficient will be maintained in a smaller state at the beginning of the train;Under the train braking condition,the increasing stiffness value of the buffer and the decreasing damping value will make the adhesion state of the locomotive fluctuate more violently.