Hunting patterns and bifurcation characteristics of a three-axle locomotive bogie system in the presence of the flange contact nonlinearity

摘要

This paper considers a three-axle railway locomotive bogie running on a straight track and presents pattern diversity and bifurcation characteristics of its hunting behaviors, at forward speeds higher than the hunting critical speed. Poincare sections describing the cycle characteristic and wheel-rail impacts of the bogie system are defined according to the geometric structure of phase space of the dynamical system for carrying out multi-target and multi-parameter co-simulation analysis. The influences of dynamical parameters of the locomotive bogie on the wheel rail impacts are studied and some important features of hunting behaviors in the presence of the flange contact nonlinearity are found. A series of grazing bifurcations induce the pattern diversity of hunting behaviors. The impacts of the middle and trailing wheelsets on the rail fall behind that of the leading wheelset, and the impact lag of the hunting motion of the middle wheelset is the most obvious of the three wheelsets. The top branch of impact velocity bifurcation diagram of period 1 hunting motion of the trailing wheelset is slightly lower than those of the leading and middle wheelsets. The instability speed of period 1 hunting-impact motion of the bogie system with worn wheelsets is lower than that with new wheelsets and the impact velocities of the worn wheelsets on the rail become smaller. A method of reasonable matching of primary suspension parameters, which brings about the substantial increase of the instability speed of periodic hunting behavior in the presence of the flange forces, is presented and the matching effect is verified by bifurcation diagrams of impact velocities of the new and worn leading wheelsets versus the forward speed. (C) 2017 Elsevier Ltd. All rights reserved.