To overcome defects caused by the complex structure and unstable damping performance of the wedge- type damper, a new lever-type friction damper has been developed for use in freight bogies; the design allows the adva...To overcome defects caused by the complex structure and unstable damping performance of the wedge- type damper, a new lever-type friction damper has been developed for use in freight bogies; the design allows the advantages of traditional three-piece bogies to be retained. A detailed description of the structure and mechanism of the lever-type damper is provided, followed by a stress analysis using the finite element method. Dynamic per- formance characteristics of the lever-type damper and the wedge-type damper are compared in terms of the nonlinear critical speed, riding index, and curve negotiation. The results indicate that the maximum stress of the lever remains below its yield limit. The lever-type car has higher running performance reliability, and achieves similar nonlinear critical speed, riding index, and curve negotiation when compared with the wedge-type car.展开更多
To study the curving performance of trains, 1D and 3D dynamic models of trains were built using nu- merical methods. The 1D model was composed of 210 simple wagons, each allowed only longitudinal motion; whereas the 3...To study the curving performance of trains, 1D and 3D dynamic models of trains were built using nu- merical methods. The 1D model was composed of 210 simple wagons, each allowed only longitudinal motion; whereas the 3D model included three complicated wagons for which longitudinal, lateral, and vertical degrees of freedom were considered. Combined with the calculated results from the 1D model under braking conditions, the behavior of draft gears and brake shoes were added to the 3D model. The assessment of the curving performance of trains was focused on making comparisons between idling and braking conditions. The results indicated the following： when a train brakes on a curved track, the wheel-rail lateral force and derailment factor are greater than under idling conditions. Because the yawing movement of the wheelset is limited by brake shoes, the zone of wheel contact along the wheel tread is wider than under idling conditions. Furthermore, as the curvature becomes tighter, the traction ratio shows a nonlinear increasing trend, whether under idling or braking conditions. By increasing the brake shoe pressure, train steering becomes more difficult.展开更多
文摘To overcome defects caused by the complex structure and unstable damping performance of the wedge- type damper, a new lever-type friction damper has been developed for use in freight bogies; the design allows the advantages of traditional three-piece bogies to be retained. A detailed description of the structure and mechanism of the lever-type damper is provided, followed by a stress analysis using the finite element method. Dynamic per- formance characteristics of the lever-type damper and the wedge-type damper are compared in terms of the nonlinear critical speed, riding index, and curve negotiation. The results indicate that the maximum stress of the lever remains below its yield limit. The lever-type car has higher running performance reliability, and achieves similar nonlinear critical speed, riding index, and curve negotiation when compared with the wedge-type car.
文摘To study the curving performance of trains, 1D and 3D dynamic models of trains were built using nu- merical methods. The 1D model was composed of 210 simple wagons, each allowed only longitudinal motion; whereas the 3D model included three complicated wagons for which longitudinal, lateral, and vertical degrees of freedom were considered. Combined with the calculated results from the 1D model under braking conditions, the behavior of draft gears and brake shoes were added to the 3D model. The assessment of the curving performance of trains was focused on making comparisons between idling and braking conditions. The results indicated the following： when a train brakes on a curved track, the wheel-rail lateral force and derailment factor are greater than under idling conditions. Because the yawing movement of the wheelset is limited by brake shoes, the zone of wheel contact along the wheel tread is wider than under idling conditions. Furthermore, as the curvature becomes tighter, the traction ratio shows a nonlinear increasing trend, whether under idling or braking conditions. By increasing the brake shoe pressure, train steering becomes more difficult.
