Tight Curves Research Articles

Railway curve squeal detection and tonal analysis

Railway curve squeal is a loud tonal noise generated by instabilities in the wheel-rail contact of railway vehicles while negotiating tight curves. The emitted noise is perceived as highly disturbing and contributes to noise problems in urban environments. Traditional monitoring of squeal occurrence involves analyzing train pass-by sound measurements. Such monitoring system is sensitive to high background noise which can pose a problem in urban environments with limited possibilities for suitable microphone placement. To overcome these issues, an alternative approach to detect curve squeal from rail vibration measurements is investigated. This comprises a simple and practical monitoring solution virtually unaffected by sound disturbances from the surroundings. Furthermore, this method can identify whether squeal noise occurs on the low or high rail. Field measurements involve a two-part analysis: 1) the development and validation of a method for detecting squealing events from rail vibrations, and 2) identifying tonal components from the measured signals. Results from the first part suggest that curve squeal can be detected from rail vibrations and the specific rail where squeal is generated can be identified. In the second part, specific frequency regions where squeal tonal components tend to emerge are recognized.

The influence of semi-actively controlled magnetorheological bogie yaw dampers on the guiding behaviour of a railway vehicle in an S-curve: Simulation and on-track test

Many publications have shown that semi-actively controlled dampers could significantly improve the behaviour of a road or rail vehicle. In the case of a railway vehicle, these dampers promise to solve the contradiction between the damping requirements of different running modes (fast running on a straight track vs negotiating a tight curve). It is known that semi-active control of a bogie yaw damper can improve the vehicle behaviour when running fast on a straight track, but it is not known whether such semi-active control worsens the vehicle behaviour when negotiating a tight curve. This paper investigates the application of magnetorheological bogie yaw dampers in the locomotive bogie to reduce guiding forces and wear in wheel-rail contact when the vehicle negotiates the S-curve. The paper describes the magnetorheological damper, its mathematical model and the strategies for its semi-active control, followed by the results of simulations on a complex multi-body locomotive model and on-track testing on a real vehicle. The simulations and on-track tests have shown that the use of semi-active control of the yaw dampers reduces the guiding force by about 10%. The reduction in these forces will lead to a reduction in wear in the wheel-rail contact.

How do long combination vehicles perform in real traffic? A study using Naturalistic Driving Data

This paper evaluates the performance of two different types of long combination vehicles (A-double and DuoCAT) using naturalistic driving data across four scenarios: lane changes, manoeuvring through roundabouts, turning in intersections, and negotiating tight curves. Four different performance-based standards measures are used to assess the stability and tracking performance of the vehicles: rearward amplification, high-speed transient offtracking, low-speed swept path, and high-speed steady-state offtracking. Also, the steering reversal rate metric is employed to estimate the cognitive workload of the drivers in low-speed scenarios. In the majority of the identified cases of the four scenarios, both combination types have a good performance. The A-double shows slightly better stability in high-speed lane changes, while the DuoCAT has slightly better manoeuvrability at low-speed scenarios like roundabouts and intersections.

Arduino Based Collision Detection and Avoidance System

Abstract: In many developing countries the usage of vehicles is increasing. Vehicles became the basic need of people now a days. Approximately 24% of land area on the earth is covered with hills and mountains. As people can’t make straight roads in mountains, they are curvy. In the upgrading countries accident is the major cause of death. If we talk about dangerous roads in the world then all of them are mountain roads and curve roads. The intensity of the deaths are more in curved roads. In the mountain roads there will be narrow roads with tight curves. In such kinds of situations the driver of a vehicle cannot see vehicles coming from other side. Because of this problem thousands of people lose their lives each year. while we are talking about mountain roads here other side might be lead to a cliff. The solution for this problem is alerting driver about the vehicle coming from other side. One of the solution is proposed in this paper. We can alert driver by placing Ultrasonic Sensor in one side of the road before the curve and keeping LED light other side of the curve, so that if vehicle comes from one end of the curve sensor will sense the vehicle and LED light glows at the opposite side as Red. By looking at the Red LED light driver can become alert and can slow down the speed of the vehicle. And still if an accident occurs we can save the life of victim by giving medical assistance immediately. This can increase the survival chances of victim. but this can happen only when we know the exact location of accidental place. This project presents an inexpensive but intelligent framework that can identify and report an accident to the family member

A Root Cause of Curve Squeal: Self-Excited Frictional Vibration of a Wheelset–Track System

Abstract When a metro vehicle navigates a tight curve, it invariably causes a squealing noise. Most researchers proposed the negative friction–velocity slope as the generation mechanism for curve squeal. However, some phenomena of railway curve squeal are still difficult to explain. The purpose of this paper is to establish a friction-coupling finite element model of the wheelset–track system that can accurately predict curve squeal and to examine the influence of different wheelset–track structures on the trend of curve squeal occurrence. It has been proposed that curve squealing is caused by self-excited frictional vibrations. The complex eigenvalue analysis (CEA) and transient dynamics analysis were applied to predict the unstable vibration of curve squeal. The impacts of the coefficient of friction between the rail and the wheel, wheel web plate shape, fastener damping, gauge, and negative friction–velocity slope on the curve squealing noise were studied. The results demonstrated that the predicted frequency corresponded to the main frequency of the squealing noise measured on-site. Simultaneously, a friction coefficient of 0.25 or higher resulted in a curve squeal with a frequency of 2153.9 Hz. An S-shaped web plate wheel, appropriate fastener damping, and gauge can reduce unstable vibrations and curve squealing when a metro vehicle navigates a tight curve. The negative friction–velocity slope has less influence on the tendency of curve squealing.

Flanging, squeal and corrugation-induced noise: Insights from recent measurement campaigns at interconnected tight curves

High noise events at tight curves often comprise of squeal, flanging and corrugation-induced noise. All noise types have the potential to cause annoyance at sensitive receivers in close proximity to the rail line. The presence of squeal, flanging and other high noise events at three interconnected sharp passenger curves on the metropolitan network in Sydney, New South Wales is investigated in the context of measured parameters. Rail and noise parameters were measured at ten locations in 2021, with a repeat of the measurements undertaken at three locations in 2022. Differences in high noise events were analysed and quantified to understand the underlying causes of curving noise in this area. The role of the wheel-rail interface contact conditions, train type, rail roughness, friction and speed is investigated to provide insights into the mechanisms leading to curving noise events at this site.

Impacts of vehicle light-weighting on wheel wear and RCF and a novel ultralight vehicle design

Vehicle light-weighting is a critical design target for rail vehicles, as it reduces energy consumption and enhances the vehicle capacity and dynamic performance, making the railway system more attractive in addressing the rising environmental challenges and increasing demand in transportation. This paper presents a quantitative analysis of the impact of vehicle light-weighting on wheel wear and rolling contact fatigue (RCF), using the USFD wear law, the shakedown map and the Tγ approach. A conventional metro vehicle is utilized as a baseline model, and the mass reductions from different vehicle components (i.e., car-body, bogie frame and wheelset) are implemented for the simulation considering various running scenarios. The effect of mass reduction on wheel wear can be divided into two aspects: quasi-static wheel load and wheel-rail dynamic interaction. In short-radius curves, the change in static axle-load predominantly determines wheel wear, whereas in large-radius curves and tangent track, the wheel-rail dynamic interaction plays an important role, thus showing different rates of wear reduction when mass reduction is achieved respectively from car-body, bogie frames and wheelsets. Reducing vehicle mass can significantly reduce wheel damage of RCF on short-radius curves with curve radii above 400 m, while there is a risk of increasing RCF on tight curve R250, due to the impaired function of wear to counteract the crack propagation. This work also exhibits a specific innovative ultralight vehicle design, where the linear synchronous motor technology is applied to reduce substantially the mass of the vehicle without impairing the capability to provide the required amount of tractive effort. The proposed ultralight vehicle can reduce the wheel wear by approximately 40% and shows substantial benefit for preventing RCF damage, compared to a conventional vehicle.

A review on the use of steerable sheaths in complex endovascular aortic repair

AbstractComplex aortic aneurysms are now more commonly treated endovascularly, and often require a fenestrated‐branched endovascular aneurysm repair. The use of steerable sheaths can improve the technical success rate in catheterisation of target visceral vessels and reduce the surgical risks associated with these complicated procedures. There are several commercially available steerable sheaths in the market, but similar devices can be homemade using different endovascular instruments. Steerable sheaths allow catheterisation of downward orientated branches more easily through a transfemoral approach. The risks associated with a traditional upper extremity access can be minimalised. They are also described in the use of several other situations during endovascular aortic repairs. Limitations to this technique are the availability of the device, the stability of the sheath curvature, the difficulty to deliver instruments in a tight curve and the associated complications if large sheaths are used. Steerable sheaths can be used as a primary intent when challenging anatomy is anticipated or as an adjunct when standard procedures are not successful.

Modeling driver steering behavior in restricted-preview boundary-avoidance tasks

In the design of human-like steering support systems, driver models are essential for matching the supporting automation's behavior to that of the human driver. However, current driver models are very limited in capturing the driver's adaptation to key task variables such as road width and visibility (i.e., ‘preview’ of the road ahead). This paper uses a recently proposed, novel control-theoretical model for centerline tracking to investigate driver steering in lane-keeping tasks with restricted and unrestricted preview, in an attempt to substantially extend this model's validity. Using data from a tailored driving simulator experiment, three driver control loops (feedforward, heading and position feedback) are separately quantified using system identification techniques. The results show that when preview is restricted, drivers use all of the remaining preview to anticipate the curves of the road ahead, and are no longer able to ‘smooth’ tight curves in the road trajectory (i.e., corner cutting). When sufficient preview and lane width are available, the time to line crossing increases, and steering behavior is less aggressive and more intermittent, or more ‘satisficing’. The novel driver steering model captures these adaptations very well (over 95% of the steering actions) and can thereby be instrumental in realizing human-like steering automation and support systems.

Dynamic analysis and experiment of chaotic circuit of non-homogeneous fractional memristor with bias voltage source

A physical memristor has an asymmetric tight hysteresis loop. In order to simulate the asymmetric tight hysteresis curve of the physical memristor more conveniently, a fractional-order diode bridge memristor model with a bias voltage source is proposed in this paper, which can continuously regulate the hysteresis loop. Firstly, based on fractional calculus theory, a fractional order model of a diode bridge memristor with a bias voltage source is established, and its electrical characteristics are analyzed. Secondly, by integrating it with the Jerk chaotic circuit, a non-homogeneous fractional order memristor chaotic circuit model with a bias voltage source is established, and the influence of bias voltage on its system dynamic behavior is studied. Once again, a fractional-order equivalent circuit model is built in PSpice and validated through circuit simulation. The experimental results are basically consistent with the numerical simulation results. Finally, the experiments on the circuit are completed in LabVIEW to validate the correctness and feasibility of the theoretical analysis. The results indicate that the fractional order memristor with bias voltage source can continuously obtain asymmetric tight hysteresis loop by adjusting the voltage of the bias voltage source. As the bias power supply voltage changes, the non-homogeneous fractional order memristor chaotic system exhibits that the period doubling bifurcation turns into chaos due to the symmetry breaking.

Energy-Based Design Optimization of a Miniature Wave-Like Robot Inside Curved Compliant Tubes

This paper analyzes the crawling locomotion of a wave-like robot in curved tubes. We use an energy-based approach to determine the optimal crawling orientation of the robot that minimizes the surface energy while advancing. The results showed that the robot rotated its body along the roll direction so that the wave motion would be in the same plane as the curvature plane of the tube. The incorporation of a passive bending joint along the plane of the wave motion decreased the surface energy and enhanced the robot's ability to advance in even tighter curves. Given these findings we designed and manufactured two new robots with either one or two passive bending joints. We molded custom flexible surfaces and tubes and experimentally tested our robots in them. These validating experiments indicated that the bending joints substantially improved the robots’ ability to traverse curved tubes (see video).

Innovative passive yaw damper to increase the stability and curve-taking performance of high-speed railway vehicles

Yaw dampers are implemented on high-speed trains to reduce their tendency towards unstable movement (hunting) while running at high-speed. Although they have a positive influence on the vehicle’s stability, these devices impose a steering resistance action on the bogies while negotiating tight curves at low speed, and so standard passive devices must be designed taking conflicting objective functions into account. This paper presents an innovative yaw damper able to overcome this trade-off by introducing a passive solution able to modify this component’s working behaviour during different vehicle operating conditions. To quantify the efficacy of this solution, numerical models of innovative and standard dampers were developed and validated by means of experimental tests. Then, they were co-simulated with a multibody model of a real test case vehicle running under different operating conditions.

Active Vibration Control for the Mitigation of Wheel Squeal Noise Based on a Fuzzy Self-Tuning PID Controller

The wheel squeal noise of a train is often made when it passes a tight curve. The noise annoys the passengers and the people living close to railway tracks. According to the research background, wheel vibration, as a result of unstable contact force, is the main source of wheel squeal noise. This study presents a novel method to reduce wheel squeal noise based on the active vibration control of wheels and the use of piezoelectric actuators attached to wheel treads. The proposed method is implemented in an experimentally validated time model involving the linear dynamics of wheel and track and nonlinear contact forces. Then, the model is modified to enhance the effect of the piezoelectric actuators. The relationship between the momentum and the voltage applied to the piezoelectric patch is also considered in modeling. To determine the amplitude and the direction of the applied voltage, a feedback controller is designed based on the fuzzy self-tuning PID controller scheme. This controller is similar to the conventional PID controller, but its coefficients are tuned by the fuzzy tuning mechanism according to the wheel response. The results show that the proposed method is capable of suppressing wheel squeal noise, especially in high frequencies. Furthermore, it is as applicable to worn wheels as to new ones.

Multibody Computer Model of the Entire Equine Forelimb Simulates Forces Causing Catastrophic Fractures of the Carpus during a Traditional Race.

Simple SummaryPalios are traditional horseraces held in the main square of few Italian cities. Due to peculiar features of such circuits, adapted to the square architecture and thus characterized by tight curves and unconventional footing surface, horses involved are at particular risk of accidents. Prevention of catastrophic musculoskeletal injuries is a significant issue and matter of debate during these events. In particular, the negotiation of the curves in the city circuits is a significative concern. An experiment was set up to build a model of entire forelimb at the point of failure in the context of a turn comparable to that in a Palio circuit. The model was informed by live data and the output compared to post-mortem findings obtained from a horse that sustained a catastrophic fracture of the carpus during this competition. The objective of this study is to determine the magnitude and distribution of internal forces generated across the carpus under which the catastrophic injury has occurred and describe related post-mortem findings.A catastrophic fracture of the radial carpal bone experienced by a racehorse during a Palio race was analyzed. Computational modelling of the carpal joint at the point of failure informed by live data was generated using a multibody code for dynamics simulation. The circuit design in a turn, the speed of the animal and the surface characteristics were considered in the model. A macroscopic examination of the cartilage, micro-CT and histology were performed on the radio-carpal joint of the limb that sustained the fracture. The model predicted the points of contact forces generated at the level of the radio-carpal joint where the fracture occurred. Articular surfaces of the distal radius, together with the proximal articular surface of small carpal bones, exhibited diffuse wear lines, erosions of the articular cartilage and subchondral bone exposure. Even though the data in this study originated from a single fracture and further work will be required to validate this approach, this study highlights the potential correlation between elevated impact forces generated at the level of contact surfaces of the carpal joint during a turn and cartilage breakdown in the absence of pre-existing pathology. Computer modelling resulted in a useful tool to inversely calculate internal forces generated during specific conditions that cannot be reproduced in-vivo because of ethical concerns.

Automated Driving Control Method in Narrow Road for Commercial Vehicles Based on Risk Potential Optimization

In order to solve the truck driver shortage that has become a problem in recent years, manpower-saving and unmanned operation of commercial vehicles is currently being actively researched and developed. However, in narrow-road driving situations such as in urban areas and parking lots, commercial vehicles have larger internal wheel track differences and overhang lengths than passenger cars. Therefore, path tracking control focusing on CG position tracking applied to passenger cars cannot be applied directly to commercial vehicles. Therefore, the purpose of this study is to develop a path planning and motion control system for automatic driving of commercial vehicles on narrow roads in a restricted area. To construct the system, we used a risk potential field that expresses the driver's sense of risk. For tight curves, the system used Triclothoid to generate a route with a large turning radius, and modified the road information to cope with the curves. The effectiveness of the above methods was confirmed by simulations using IPG TruckMaker.

Impact of mountainous interstate alignments and truck configurations on rollover propensity

Introduction: Combined horizontal and vertical alignments are frequently utilized in mountainous interstates in Wyoming. The roll stability of trucks on these challenging terrain conditions is of great concern for transportation officials. The impact of curve characteristics combined with truck configurations has not been considered in the literature due to data availability issues related to the weight and Center of Gravity (CG) payload height of trucks. Method: High-fidelity vehicle dynamics simulation modeling is employed to investigate the rollover propensity of trucks navigating curves of varying geometric design and truck characteristics. A multinomial regression model was then developed to further quantify the impact of these key factors and the effect of their interactions on rollover safety margins. Results: It was shown that complying with the assigned speed limits of the curved roadways is not enough to navigate a curve without experiencing a rollover under some circumstances. The CG payload height and the operating speeds have the highest impact on the safety margins of a truck rollover. Steeper downgrades would amplify the impact of the gross weight of a truck. Tighter curves would also raise the impact of the truck configurations. Conclusions: This study assessed the curve speed limits and revealed that the exciting approach to assigning safe speed limits should be modified according to the aforementioned factors. For the first time, findings from this study shed light on the direction and magnitude of the impact of the truck configurations coupled with curve features that contribute to truck rollover safety margins. Practical Applications: This study revealed the impact of truck configurations on the roll stability of trucks and pointed out critical cases that should be treated very cautiously by drivers. This assists transportation agencies in assigning more appropriate speed limits of curved roadways according to truck conditions.

Running safety analysis of a freight train passing through a single crossover during braking

In addition to the discontinuity of the rail profile of a normal turnout, the unique S-shaped curve of a crossover significantly affects the negotiation performance of a train. For heavy-haul freight trains, the in-train forces generated during the braking process may further deteriorate the running safety. Investigating the dynamic behaviour of the train passing through the crossover under braking forces, therefore, can provide a reasonable basis for ensuring train safety. This paper analyses the dynamic response and wheel wear of a three-vehicle train negotiating a single crossover under variable conditions, including variable braking forces, wheel-rail friction coefficient, and crossover layout forms. The results show that the three factors have considerable influences on train safety. If one of the three factors keeps an ideal level, the safe probability of empty wagons can be significantly improved. Considering that there are still some crossovers with tight curves in the existing railway system, avoiding large braking or lubricating the wheel flange in the crossover is still an effective solution to improve the vehicle's performance. In addition, for a new single crossover, a 600-m-radius curve is a good option for balancing permissible train speeds and construction costs of the crossover.

Vehicle Alerting and Accident Detection System at Hairpin Bend Curves Using IOT

In the developing countries accident is the major cause of death. “Speed Kills”, but still people don’t care enough to act safe while driving on road. Road traffic accidents and deaths caused by them are most critical issues now days. It is also impacting the country’s economy. According to Million Death Study (MDS) about 2.3 million people die in India per year. In that 137 thousand is because of road accidents. That is about 377 people per day. In that 3.7% because of failed to look the road. We can see that many of them are curve roads. In the mountain roads there will be tight curves and the roads will be narrow. In these kinds of situations the driver of a vehicle cannot see vehicles coming from opposite side on the roads. Thousands of people lose their lives each year because of this problem. Since we are talking about mountain roads here other side might lead to a cliff and heavy bends. The solution for this problem is alerting the driver about the vehicles coming from opposite side in Ghats sections. This is done by keeping an ULTRASONIC SENSOR on one side of the road before the curve and keeping a LED light after the curve, so that if a vehicle comes from one end of the curve, sensor senses and LED light glows at the opposite side. By looking at the LED light on/off criteria driver can be alert and can slow down the speed of the vehicle.

Road Safety at Ghats using IoT

This paper describes how to overcome accidents at Ghat roads. In the developing countries accident is the major cause of death. If we look at the top 10 dangerous roads in the world we can see that all of them are mountain roads and curve roads. In the mountain roads there will be tight curves and the roads will be narrow. In these kinds of situations the driver of a vehicle cannot see vehicles coming from opposite side. Thousands of people lose their lives each year because of this problem. The solution to this problem is developing the Aurdino based project to provide safe and secure journey while travelling to the Ghat roads, Hill Stations, etc. It is provided by alerting the driver about the vehicle coming from opposite side. This is done by keeping a sensor in one side of the road before the curve and keeping a LED light after the curve, so that if vehicle comes from one end of the curve sensor senses and LED light glows at the opposite side. By looking at the LED light on/off criteria driver can become alert and can slow down the speed of the vehicle.

Detection of Geometric Risk Factors Affecting Head-On Collisions through Multiple Logistic Regression: Improving Two-Way Rural Road Design via 2+1 Road Adaptation.

This study aims to characterize locations on two-way rural roads where head-on crashes are more likely to occur, attending to geometric road design factors. For this purpose, a case-control study was carried out using multiple logistic regression models with variables related to road design parameters, considering several scenarios. The dataset corresponding to cases (places where crashes have occurred) was collected on Spanish “1+1” rural roads over a four-year period. The controls (places where no crashes have occurred in the period) where randomly selected through a specific ad hoc designed method. The obtained model identifies risk factors and allows the computation of the odds of a head-on collision on any specific road section: width of the pavement (when it exceeds 6 m), width of the lanes (for intermediate widths between 3.25 and 3.75 m) and tight curves (less than 250 m of radius) are identified as factors significantly increasing the odds of a crash, whereas a paved shoulder is a protective factor. The identified configurations on two-way rural roads may be susceptible to transformation into “2+1” roads to decrease the odds of a head-on crash, thus preventing possible serious injuries and enhancing transportation safety.