Z. Li
226 records found
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As a critical factor in the degradation of rails and wheels, wheel-rail contact heat has been investigated with various analytical and numerical methods. However, the predicted temperature distributions and thermal loads have not been directly validated through measurements due t
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This study experimentally and numerically investigated wheel–rail rolling contact fatigue (RCF), focusing on the initiation mechanisms of head check (HC). The experimental study was conducted using V-Track, a scaled test rig developed at TU Delft that is able to simulate real-lif
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Detection of Rail Surface Defects based on Axle Box Acceleration Measurements
A Measurement Campaign in Sweden
This work presents the results of a measurement campaign to demonstrate the effectiveness of the axle box acceleration (ABA) technology for detecting rail defects. The measurements were conducted along the Iron Ore line between Sweden and Norway for the IN2TRACK3 project. This li
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A train-borne laser Doppler vibrometer (LDV) directly measures the dynamic response of railway track components from a moving train, which has the potential to complement existing train-borne technologies for railway track monitoring. This paper proposes a holistic methodology to
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Vibrations resulting from dynamic vehicle-track interactions (VTI) offer valuable insights into track conditions. This paper presents an approach for track condition monitoring by detecting and quantifying multiple track degradations using a digital twin of the VTI system. Unlike
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This article develops and tests a self-contained railway track monitoring system that fits in existing vehicles without the need for speed and load control. Combining a train-borne laser Doppler vibrometer and axle box accelerometers enables synchronized measurements of train-tra
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Short pitch corrugation is a typical defect on rail surfaces that induces high level of noise and increases maintenance costs. Despite numerous research efforts, corrugation development mechanism has not yet been fully understood and root-cause solutions have not been developed.
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A transfer function (TF) is an effective representation of the load-response relationship of railway track structures. To fill the gap in measuring track structure TFs over a wide frequency range from a moving vehicle, we develop a TF measurement system and the associated TF esti
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Wheel-rail high-frequency interaction is closely related to the formation of railway short-wave defects. Finite element (FE) method has been widely used to simulate wheel-rail dynamic systems, but its validity in modelling high-frequency interaction has not been fully demonstrate
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Vibration transfer from underground train to multi-story building
Modelling and validation with in-situ test data
Excessive underground train-induced vibration becomes a serious environmental problem in cities. To investigate the vibration transfer from an underground train to a building nearby, an explicit-integration time-domain, three-dimensional finite element model is developed. The und
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The Coefficient of Friction (CoF) is an important parameter affecting acceleration and braking behavior of trains, and consequently the inter-train distance and utilization of track. To optimize operation schedules, maximize railway capacity, and realize automatic train operation
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The conventional vertical track quality index (TQI) based on the standard deviation of longitudinal levels yields standardized railway track condition assessment. Nevertheless, its capability to identify problems is limited, particularly in the ballast and substructure layers whe
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Friction/adhesion management in railway networks is a challenge for infrastructure managers and railway operators. Friction/adhesion at the wheel–rail interface influences the braking and traction performance of railway vehicles and the formation of wheel and rail defects. A mini
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Polygonal wear is a type of damage commonly observed on the railway wheel tread. It induces wheel-rail impacts and consequent train/track components failure. This study presents a finite element (FE) thermomechanical wheel-rail contact model, which is able to cope with the three
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Vertical dynamic measurements of a railway transition zone
A case study in Sweden
This study presents a measuring framework for railway transition zones using a case study on the Swedish line between Boden and Murjek. The final goal is to better understand the vertical dynamics of transition zones using hammer tests, falling weight measurements, and axle box a
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Excessive underground train-induced building vibration is an environmental concern resulting in human distress. Wheel polygon is probably one of the main vibration sources. In the present work, an explicit-integration time-domain, fully coupled 3D dynamic train-track-tunnel-soil-
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Condition monitoring of railway transition zones using acceleration measurements on multiple axle boxes
Case studies in the Netherlands, Sweden, and Norway
Railway transition zones connecting conventional embankments and rigid struc-tures, such as bridges and tunnels, usually degrade much faster than other railway sections. Efficient health condition monitoring of transition zones is important for preventative track maintenance. In
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Railway track stiffness is an important property closely related to track condition and maintenance. Track stiffness variations occur over time and space due to dynamic train loading and aging of track components. Track stiffness variations may further lead to geometry deteriorat
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Inefficient management of rail surface defects can increase maintenance costs, safety hazards, service disruptions, and catastrophic failures like rail breaks. To achieve adequate management, having effective technology capable of timely detecting and frequently monitoring rail d
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This paper aims at identifying the formation mechanism of short pitch rail corrugation using an improved configuration of a 1/5 scaled V-Track test rig. The loading conditions of the V-Track are designed to simulate the wheel-rail dynamic interactions on the tangent track. Corrug
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