Abstract:Tread braking is a common friction-based braking system that finds use on metro and suburban trains. Here the wheels are safety-related components and there is a need to develop design specifications and guidelines to ensure that the wheels perform properly under the service conditions to which they are exposed. In the present paper, examples of applications are given that employ a modelling framework that was developed in a companion paper. The examples represent typical conditions in metro and suburban opera… Show more
“…Teimourimanesh et al. 3 found that wheel gauge reduces during stop and drag braking and increases during subsequent cooling of wheels. S-type wheel profile resulted in lower axial deflections as compared to straight plate wheel profile.…”
Field statistics of the wheelsets of gauge-widened coaches in the Indian Railways show higher tendency for excessive wheel gauge widening for lower diameter wheelsets. Additionally, the axial flange deflection in gauge-widened wheelsets increases nearly linearly with the radial distance. In this work, a finite element model is developed to investigate the reasons behind these field observations. The model considers heat generation during braking, heat loss to rail, brake blocks, ambient air, residual stresses generated during wheel manufacturing, and material removal during wheel reprofiling. Wheel gauge evolution is studied for different braking histories, including those that span the entire life period of the wheel, i.e. as the wheel diameter reduces from its initial to minimum allowable size. Simulations show that higher wheel rim temperatures and lower wheel stiffness, for lower diameter wheels, result in higher wheel gauge widening for these wheelsets. Wheel gauge widening occurs primarily due to bending at the hub–disc interface; consequently, the axial flange deflection increases linearly with the radial distance.
“…Teimourimanesh et al. 3 found that wheel gauge reduces during stop and drag braking and increases during subsequent cooling of wheels. S-type wheel profile resulted in lower axial deflections as compared to straight plate wheel profile.…”
Field statistics of the wheelsets of gauge-widened coaches in the Indian Railways show higher tendency for excessive wheel gauge widening for lower diameter wheelsets. Additionally, the axial flange deflection in gauge-widened wheelsets increases nearly linearly with the radial distance. In this work, a finite element model is developed to investigate the reasons behind these field observations. The model considers heat generation during braking, heat loss to rail, brake blocks, ambient air, residual stresses generated during wheel manufacturing, and material removal during wheel reprofiling. Wheel gauge evolution is studied for different braking histories, including those that span the entire life period of the wheel, i.e. as the wheel diameter reduces from its initial to minimum allowable size. Simulations show that higher wheel rim temperatures and lower wheel stiffness, for lower diameter wheels, result in higher wheel gauge widening for these wheelsets. Wheel gauge widening occurs primarily due to bending at the hub–disc interface; consequently, the axial flange deflection increases linearly with the radial distance.
“…An important aspect of these effects, when it comes to assessing the thermal capacity of railway wheels, is the ‘thermal fuse’ function of the brake blocks, see below, which will be analysed and discussed in the companion paper. 22…”
Section: Modellingmentioning
confidence: 99%
“…A safe performance of the wheels depends on their ability to tolerate not only the repeated stresses imposed by normal loads and different braking conditions, but also the occasional high stresses that develop under abnormal operational conditions, such as increased lateral design loads for the metro that may occur because of high proportions of curves. In the companion paper, 22 this factor is considered. Figure 5.Standard mechanical load cases and definition of loads used in fatigue analysis.…”
Section: Modellingmentioning
confidence: 99%
“…The influence from the varying mean stresses and load combinations are studied in detail in the companion paper. 22…”
Tread brakes are still a common frictional braking system used on metro and suburban trains. Here the wheels are safety-related components and there is a need to develop design specifications and guidelines to ensure that the wheels perform properly under the service conditions to which they are exposed. In the present paper, a model is proposed and developed that represents typical conditions in metro and suburban operations, in particular during sequential stop braking. The analysis also considers drag braking, mechanical loading, residual stresses and wheel–axle interference fit. Finite element modelling, with an advanced temperature-dependent material model, together with a fatigue analysis is employed to quantify the wheel’s performance. An application example demonstrates the method for a typical metro wheel. In a companion paper, further applications are presented that demonstrate important aspects of the thermal capacity of tread-braked railway wheels.
“…Teimourimanesh et al [15] studied different drag and stop braking scenarios for metro and freight car wheels subjected to synchronized braking. Teimourimanesh et al [16] and Teimourimanesh et al [17] studied axial flange deflections of straight plate and Sshaped metro wheels having diameters 700-850 mm. A 2D FE model incorporating residual stresses from heat treatment process and press fit was used in these works.…”
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
