Optimization of Rail Profiles to Improve Vehicle Running Stability in Switch Panel of High‐Speed Railway Turnouts

Abstract

A method for optimizing rail profiles to improve vehicle running stability in switch panel of high-speed railway turnouts is proposed in this paper. The stock rail profiles are optimized to decrease the rolling radii difference (RRD). Such characteristics are defined through given rail profiles, and the target rolling radii difference is defined as a function of lateral displacements of wheel set. The improved sequential quadratic programming (SQP) method is used to generate a sequence of improving profiles leading to the optimum one. The wheel-rail contact geometry and train-turnout dynamic interaction of the optimized profiles and those of nominal profiles are calculated for comparison. Without lateral displacement of wheel set, the maximum RRD in relation to a nominal profile will be kept within 0.5 mm–1 mm, while that in relation to an optimized profile will be kept within 0.3 mm–0.5 mm. For the facing and trailing move of vehicle passing the switch panel in the through route, the lateral wheel-rail contact force is decreased by 34.0% and 29.9%, respectively, the lateral acceleration of car body is decreased by 41.9% and 40.7%, respectively, and the optimized profile will not greatly influence the vertical wheel-rail contact force. The proposed method works efficiently and the results prove to be quite reasonable.

Parameters Studies on Surface Initiated Rolling Contact Fatigue of Turnout Rails by Three-Level Unreplicated Saturated Factorial Design

“…The turnout model is an elastic track model (Figure 9) established according to a Chinese CN60-1100-1:18 high-speed railway turnout. For the detailed establishment of the models, see references [8,30]. …”

“…. , mexisting results greater than 1 (8) where, m is the total number of times the experiment has been conducted, EMS i is the mathematical expectation of the mean square error. The equation for the mean square error MS i is shown below [33,34]:…”

“…In addition, they also evaluated the structural design of turnout switches based on this method. Markine, Wan and Wang et al [6][7][8] optimized the track stiffness and rail profiles in order to reduce the dynamic wheel-rail interaction at turnout zones and solve problems such as rail wear and fatigue of turnout rails. Pletz et al [9] presented a finite element model for crossing with a single running wheel according to the wheel-rail vibration, elastic wheel deformation and plastoelastic rail deformation, in order to calculate the dynamic wheel-rail interaction, then they also presented a simplified finite element model for calculating the dynamic wheel-crossing interaction [10], according to the influence of grid precision and calculation time, through setting appropriate grid sizes.…”

Numerical Investigation into the Effect of Geometric Gap Idealisation on Wheel‐Rail Rolling Contact in Presence of Yaw Angle

“…The last two conditions are also termed non-Hertz geometry. For computational efficiency, the first geometric gap is adopted by most vehicle-track dynamic models to get a global force [1][2][3][4], and the second one is usually used for a detailed wheel-rail rolling contact solution even if the actual contact 2 Mathematical Problems in Engineering shape is asymmetric [5][6][7]. To the best of authors' knowledge, a thorough study of wheel-rail rolling contact considering asymmetric geometry is rare.…”

“…Combination of Hertz theory [8] and ellipse shape based tangential method such as Kalker's FASTSIM algorithm [9] or Shen-Hedrick-Elkins model [10] are widely used in vehicletrack dynamics for fast calculation [1][2][3][4]. In this case, one basic assumption is the two contacting bodies are represented by second degree polynomials, meaning contact shape is elliptic.…”