Design method of worn rail grinding profile based on Frechet distance method

Abstract

Due to the large volume and high running density of railway freight lines, rail deterioration occur frequently. Thus, it is necessary to grind the rail in time to improve the wheel-rail relationship. The profile data of the worn rail were measured at different measuring points in a section, and the Frechet distance method was adopted to analyze the data. The representative profile reflecting the overall condition of rail wear in this section is obtained. Combined with NURBS curve theory, a fitting algorithm in which the rail profile with certain discrete points was established. Taking the reduction of the amount of grinding material removed as the objective function, setting wheel-rail matching characteristics, and the reduction of rail wear as the constraint conditions, a calculation model for rail grinding profile was established. The dynamic characteristics of standard profile CN75 and g grinding profile OP75 were analyzed by the vehicle track dynamics model. The results showed that compared with the standard profile CN75, the amount of grinding material removed of the grinding profile OP75 is reduced by 44.7%, and the height reduction of the rail top is reduced by 0.39 mm. After [Formula: see text] km of running, the wear amounts of grinding profile OP75 is about 36.1%–36.5% less than that of standard profile CN75.In the small curve section, the derailment coefficient of grinding profile OP75 is reduced by 11.7% compared with that of standard profile CN75. The dynamic performance is improved. The grinding target profile has better dynamic characteristics and is beneficial to reduce wheel-rail wear.

Design Method of Worn Rail Grinding Profile for the Curve Section

“…The contact spot area reaches the minimum value of 108.5 mm 2 when the wheelset lateral displacement is 16 mm, which is reduced by 41.3% compared with 184.9 mm 2 at 8 mm. This is because the wheel-rail contact presents a single Here, R grindÀreal has two-point contact or conformal contact when the wheelset lateral displacement is within [12,20] mm, while for R transÀopt and R consÀopt two-point contact occurs at 20 mm, so the contact state of the optimized design profile is obviously improved. Figure 16b shows that the maximum von Mises stress of R grindÀreal has no obvious change when the wheelset lateral displacement is within [0,8] mm, but when the wheelset lateral displacement is within [8,16] mm, because of the stress concentration in advance, the stress of R grindÀreal increases significantly at 16 mm.…”

“…Assume that the binary group ( S,d ) is a metric space, where d is a metric function on S . For any two continuous curves A and B on S , there are A : [0,1]→ S , B :[0,1]→ S , and for two parameterized functions α and β on the unit interval, there are α : [0,1]→ S , β : [0,1]→ S , α ( 0 ) = 0 , α ( 1 ) = N , β ( 0 ) = 0 , β ( 1 ) = N ( 12 ).…”

“…Huang ( 10 ) proposed an optimization design method of the rail grinding profile based on the analysis of wheel–rail contact stress, and verified the feasibility of this method by comparing the wheel–rail contact geometric performance and contact stress before and after optimization. Lin et al ( 11 , 12 ) proposed a smooth design method for constructing a rail profile with multi-parameter variables, such as a multi-section arc and radius, and then established a cubic NURBS description method for the rail profile based on NURBS theory, and obtained the optimized profile through the optimization algorithm. Zhou ( 13 ) adopted the reverse method of the wheel–rail contact angle curve to design a rail profile with high commonness, which effectively improved the wheel–rail contact state.…”

Influence of rail weld irregularity on dynamic stress of bogie frame based on vehicle-track rigid-flexible coupled model

“…Many researchers have developed various kinds of track models (Pålsson et al, 2021; Sun et al, 2022) to study the influence of turnout and the wear mechanism between the wheel/rail contact (Kisilowski and Kowalik, 2021; Milosevic et al, 2022). The corresponding condition monitoring methods related to the bogie (Lai et al, 2021) and other grinding schemes (Lin et al, 2021) are proposed. But few of them focus on the relationship between the turnout and vibration fatigue of the vehicle.…”