An investigation into the causes of squats—Correlation analysis and numerical modeling

Li, Zili; Zhao, Xin; Esveld, C; Dollevoet, Rolf; Molodova, Maria

doi:10.1016/j.wear.2008.02.037

Cited by 168 publications

(182 citation statements)

References 8 publications

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“…A typical squat with W-shape profile [58] was applied on the rail surface of the full-size model. Applying the linear scale Fig.…”

Section: Fe Modelling With Squat Defectmentioning

confidence: 99%

Development of a New Downscale Setup for Wheel-Rail Contact Experiments under Impact Loading Conditions

Naeimi

Petrov

et al. 2017

Exp Tech

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A new downscale test rig is developed for investigating the contact between the wheel and rail under impact-like loading conditions. This paper presents the development process of the setup, including review and synthesis of the potential experimental techniques, followed by scalability, mechanical and operational analysis of the new setup. The new test rig intends to remedy the lack of dynamic similarity between the actual railway and the existing laboratory testing capability, by taking into account the factors that contribute to high-frequency dynamics of the wheel-track system. The paper first reviews the functionalities of the existing test techniques in the literature. Based on this survey, the category of the scaled wheel on the rail track ring is chosen. Afterwards, three potential alternatives are identified under the chosen category and the optimum mechanism is achieved through finite element modelling and analysis of the structures. A downscale test rig, consisting of multiple wheel components running over a horizontal rail track ring, effectively fulfilled the requirements needed for analogical testing of the wheel-rail contact behaviour. The new test rig is a unique experimental setup due to the involvement of high-frequency dynamic vibrations in the wheel-track system and analogy of the incorporated elements and loading to those of the real-life system. This paper further presents the results of some real experiments carried out using the newly-built setup to support substantial ideas behind its development.

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“…A typical squat with W-shape profile [58] was applied on the rail surface of the full-size model. Applying the linear scale Fig.…”

Section: Fe Modelling With Squat Defectmentioning

confidence: 99%

Development of a New Downscale Setup for Wheel-Rail Contact Experiments under Impact Loading Conditions

Naeimi

Petrov

et al. 2017

Exp Tech

Self Cite

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“…2 illustrates a 3D transient rolling contact FE model developed with ANSYS/LS-DYNA, which considers a high-speed vehicle and a typical slab track on a Chinese high-speed line. The modeling approach for the vehicle is the same as that used by Li et al (2008) and Zhao and Li (2011). The track is composed of the rail, fastenings, slabs, and the mortar layer.…”

Section: Fe Modelmentioning

confidence: 99%

“…The FE modeling approach employed in this study origins from that published in (Li et al, 2008). This approach has been validated by Li et al (2008; and Molodova et al (2011) for the high frequency vehicle-track interaction at squats (in the frequency range between a few hundred and about 2000 Hz), and by Zhao and Li (2011) for the normal and tangential contact solutions.…”

Section: Introductionmentioning

confidence: 99%

“…This approach has been validated by Li et al (2008; and Molodova et al (2011) for the high frequency vehicle-track interaction at squats (in the frequency range between a few hundred and about 2000 Hz), and by Zhao and Li (2011) for the normal and tangential contact solutions. Li et al (2012) employed the FE modeling approach to study the wheel-rail rolling contact on corrugation and the 80 mm resulting wear pattern at a speed of 108 km/h, for which a ballasted track was considered.…”

Section: Introductionmentioning

confidence: 99%

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Modeling of high-speed wheel-rail rolling contact on a corrugated rail and corrugation development

Zhao

Wen

Heng-yu

et al. 2014

JZUS-A

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Short pitch rail corrugations were observed on a recently opened Chinese high-speed line. On the basis of field measurements and observations of corrugations occurred on the high-speed line, a 3D transient rolling contact model is developed using the explicit finite element (FE) method to investigate high-speed vehicle-track interactions in the presence of rail corrugations. The rotational and translational movements of the wheel are introduced as initial conditions in the model. The frictional rolling contact between the wheel and the corrugated rail is solved by a penalty method based surface-to-surface contact algorithm with Coulomb's law of friction. The contact filter effect is considered automatically by the finite size of the contact patch. Through specifying a time-dependent driving torque applied to the wheel axle, the tangential vehicle-track interaction on the corrugated rail is analyzed in the time domain together with the normal one at different traction levels and at rolling speeds of up to 500 km/h. This analysis focuses on detailed contact solutions, such as distributions of the pressure, surface shear stress, Von Mises (V-M) stress, and frictional work. The corrugation dimensions, traction level, and rolling speed are varied to investigate their influences, building a solid basis for further studying the material damage mechanisms. A theory is proposed based on the simulations to explain the observed phenomenon that the corrugation gradually stabilizes. The traditional multi-body approach is found to overestimate the dynamic wheel-rail interaction on a corrugated rail.

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“…While rail damage in conventional mainline routes has been primarily investigated within previous studies (Li et al 2008;Olofsson and Nilsson, 2002;Girsch and Heyder, 2003), there has been less emphasis placed on the development of RCF cracking in metro-underground systems. However, with the changing track characteristics, the high traffic demand as well as the reduction in the available maintenance times, means that the management of RCF cracks is also of vital importance on these lines.…”

Section: Introductionmentioning

confidence: 99%

Prediction of RCF Damage on Underground Metro Lines

Boyacioglu¹,

Bevan²,

Vickerstaff

2018

Icrt 2017

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London Underground (LUL) is one of the largest metro networks in the world and carried nearly 1.5 billion passengers in 2015. This increasing passenger demand leads to higher axle loads and shorter headways in the railway operations. However, this has a detrimental impact on the damage generated at the wheel-rail interface. In spite of the advances in rolling stock and track engineering, new developments in material manufacturing methods and rail inspection technology, cracking in rails still remains a major concern for infrastructure managers in terms of safety and maintenance costs. In this study, field data from two metro lines on the LUL network was analysed to identify the distribution and severity of the different damage types. Detailed vehicle dynamics route simulations were conducted for the lines and the calculated wheel-rail forces were investigated to assess the applicability current models for the prediction of rail damage on metro lines. These models include the Whole Life Rail Model (WLRM), previously developed for Great Britain (GB) main line tracks, and Shakedown theory. The influence of key factors such as curve radius, different friction conditions, track irregularities and wheel-rail profiles on the wheel-rail contact interface have been evaluated and compared with outputs from simulations on mainline routes. The study found that the contact patch energy (Tγ) and the interaction between wear and RCF in rails were highly influenced by the characteristics of metro tracks. It was also shown that both the Tγ and Shakedown methods can provide successful prediction of damage susceptibility of rails. However, in order to increase the accuracy of damage predictions and to ascertain the severity of different damage types, the duty conditions which are observed by the rail and the changes in contact conditions resulting from the successive vehicle passes should be considered in the modelling.

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An investigation into the causes of squats—Correlation analysis and numerical modeling

Cited by 168 publications

References 8 publications

Development of a New Downscale Setup for Wheel-Rail Contact Experiments under Impact Loading Conditions

Development of a New Downscale Setup for Wheel-Rail Contact Experiments under Impact Loading Conditions

Modeling of high-speed wheel-rail rolling contact on a corrugated rail and corrugation development

Prediction of RCF Damage on Underground Metro Lines

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