Trailer Bogie Research Articles

Effect of polygonal wheel on the vehicle-track dynamic interaction in turnout and its transmission to the trailer bogie wheels

The dynamic interaction between the vehicle and track is strongly influenced by out-of-round wheels and turnout rail profile geometries, which result in high-magnitude contact forces and abnormal vibrations. This study presents the dynamic response of the tram-turnout interaction due to polygonal wheel wear and analyses its transmission between the wheelsets. A three-dimensional coupled tram-turnout dynamic model was formulated, taking into account the polygonal wear on the front bogie wheelsets. Through numerical simulations, the dynamic characteristics of a tram passing through the turnout switch and crossing panels under the influence of polygonal wear were simulated. Furthermore, the impact of polygonal wear amplitudes and tram speeds on the transmission of dynamic impact forces and vibrations from the front bogie wheelset to the trailer bogie wheels are described. According to the numerical findings, when the flexible wheelset experiences polygonal wear, it can lead to substantial impact forces and vibrations as the tram moves through the turnout switch and crossing zones. Moreover, the transmission of dynamic impact forces and vibrations from the front bogie wheelset to the trailer wheels increases as the wheel wear amplitude and the vehicle speed increase.

ANALISIS LAJU KEAUSAN BRAKE PAD TERHADAP DISC BRAKE KERETA LISTRIK LRV SERI 1100

The brake pad is a critical component in the LRV braking system. Based on maintenance data on the LRV Series 1100 shows that there is a decrease in the thickness of the brake pad. The braking system on the LRV has two types of braking, which are regenerative braking and pneumatic braking. Regenerative braking is a braking system that works by utilizing kinetic energy in motor traction. Pneumatic braking is a braking system that works by utilizing compressed air which moves the calipers and is forwarded to the brake pads to grip the disc brakes. The purpose of this study is to determine the wear rate of the brake pads so that the prediction of the service life of the brake pads is known and to find out the factors causing the differences in the wear rates of the brake pads attached to the bogie trailer and the bogie motor. The method used in this study is linear regression, by processing maintenance data and collecting data in the field so that the factors that influence the wear rate and differences in the rate of wear on the brake pads are obtained. After analyzing the data, the brake pad on the McA bogie brake pad can be achieved in November 2039 with a thickness of 8.06 mm, the McB bogie in June 2042 with a thickness of 8.03 mm, on the trailer bogie in November 2029 with a thickness of 8.12 mm. The braking force between the brake pad and disk brake on the McA and McB bogies was 98.26 kgf, the braking friction that occurred had an impact on the wear rate of the McA and McB bogie brake pads which was 1.11 x 10-6 mm3/Nm. Whereas in the bogie trailer, the braking force between the brake pad and disk brake is 25.24 kgf, the braking friction that occurs affects the brake pad wear rate of 10.01 x 10-6 mm3/Nm. The factors that affect the difference in wear rate are the regenerative braking function and the pneumatic braking itself, on bogies McA and McB brake pads work at speeds of 15 km/h to 0 km/h, while on bogie trailers from a maximum operating speed of 60km/h to 0 km /j uses the pneumatic braking function.

Evaluation of the dynamic behaviors of a train braking system considering disc–block interface characteristics

Disc–block interface properties have prominent influence on the dynamic behaviors of train braking systems. In this study, the tribological characteristics of small-scale train friction blocks with different perforation diameters at the centre of the block surface were investigated using a disc–block test rig. And the Stribeck model parameters of the disc–block friction interface were identified to intuitively characterize the evolution law of stick–slip characteristics with the variation of block perforation diameters. Then, a trailer bogie braking system model of a high-speed train considering the coupling effects between the essential brake unit, wheelset and bogie frame was established. And the identified Stribeck parameters were introduced into the proposed braking system dynamics model to establish a relationship between the friction characteristics of the disc–block interface and the dynamic behaviors of the train braking system. Based on this, the cross-scale analysis was performed to evaluate the dynamic performance of a train braking system affected by the perforated friction block via classical stability theory and numerical simulation. The results show that the friction block with a perforation diameter of 3 mm can effectively suppress the stick–slip vibration of the disc–block friction interface, then reducing the oscillation of system components and enhancing the stability of the entire trailer bogie system.

Experimental characterization of the vibration effects on wheels of a mass rapid transit vehicle

The aim of this paper is to present the results coming from an experimental campaign aimed at the definition of the vibrations acting on a powered and a trailer bogie of a railway vehicle for mass rapid transit during commercial service. The results, coming from multiple sensors placed in specific points of the two wheelsets, can give a significative overview of the dynamic behaviour of the two components, highlighting, when present, notable differences. The available sensors gave the possibility to justify and correlate these differences to specific characteristics of the bogies considered. The study stresses the presence of peculiar cyclic solicitations that the wheels and the wheelset undergo during their service. A deeper investigation of the outcoming signals has been carried out keeping into consideration the frequency content associated to the specific measurement system in use. The results of the experimental campaign highlight that powered wheelsets may experience significant high-frequency vibrations induced by gear pairs. The implications of these findings may represent a significant argumentation in the discussion of the design requirements of wheelsets and wheels.

A novel dynamics model of a trailer bogie brake system and its application in stability analysis

The dynamic performance of the trailer bogie brake system is essential for the safe operation of a high-speed train during the braking process. In this work, we developed a novel ten-degree-of-freedom (ten-DOF) dynamics model of a trailer bogie brake system based on dynamic and tribological theories. The non-linear factors including disc-pad non-linear friction and wheel-rail non-linear interactions were considered. The field test results demonstrated that more intense vibrations occur at low vehicle speeds, which is also supported by numerical simulations based on the novel dynamics model. The abnormal vibration is caused by the limit cycle oscillation of the brake unit, and it leads to the instability of the whole system. To further understand the instability of the trailer bogie brake system, the equilibrium points and the linear stability of the system under different braking conditions and suspension parameters were investigated based on the Lyapunov theory. Then, the non-linear vibration response and stability of the trailer bogie brake system affected by the suspension parameters were further calculated by numerical integration methods. The results demonstrated that the mounting stiffness of the brake unit approached 3.4×107N/m and the primary suspension stiffness approached 6.0×105N/m or remained within the range of 10×105-14×105N/m, causing more violent vibrations and increased system instability. A primary suspension damping exceeding 2.4×104N·s/m was conducive to improving system stability.

Analysis of Front and Rear Asymmetric Wheelset Applying Switch Control of Individual Motor and Active Coupler to Improve Running Performance of Independently Rotating Wheel Type Railway Vehicle

The low floor tram, which has been recently introduced, uses an independently rotating wheelset to achieve 100% low-floor structure and improve the running performance of curves. The independently rotating wheelset is designed to allow smooth curve driving by allowing the left and right wheels to rotate freely, allowing the outer wheels to rotate faster during sharp curves. As the rotational constraints on the left and right wheels disappeared, the lateral restoring force, which is inherent to railroad wheels, also decreased. Lack of resistance to disturbance may cause continuous flange contact or, in severe cases, zigzag driving while repeatedly impacting the left and right flanges. To overcome these shortcomings, research on guide mechanisms and steering mechanisms has been carried out, but there are few cases in which actual vehicles have been applied due to many operational problems with the attachment of additional devices or complicated systems. Considering the superior running characteristics of rigid wheels when driving straight and the characteristics of independently rotating wheels when running on curves, front and rear asymmetric bogies using a combination of two types of wheelsets have also been proposed. The front and rear asymmetric bogie must be able to improve the driving performance only when the front shaft is a rigid wheel, and on the contrary, the stability is worse. In this paper, the performance of the front and rear asymmetric bogies is verified through analysis and small-scale roller rig test. In order to improve the shortcomings of the fixed asymmetric bogies, the switch control method of the individual motor control is applied to the motor bogie and the switch control method using active coupler for the trailer bogie were proposed. The performance improvement effect of switch control was verified through analysis and test. The switch control is a practical control method that can be applied directly to a real vehicle by applying a very simple and effective control method and plans to verify the performance improvement effect through actual vehicle test in the future.

Structural Simulation and Strength Analysis for Trailer Bogie Frame of High-Speed Train Based on CATIA and ANSYS Workbench

Background: As a key component of the rail transit vehicle, the railway bogie greatly affects the dynamic performance, reliability, and safety of the high-speed rail vehicle. In this paper, the structural strength of a typical trailer bogie frame is evaluated and its strength and dynamic requirements are verified. In addition, various patents on bogie structural strength have also been discussed in this paper. Objective: The study aimed to evaluate and verify the rationality of the bogie frame structure design with static strength and dynamic characteristics. Methods: A three-dimensional model of the trailer bogie frame was built by CATIA V5, and then, a finite element model of the frame was analyzed by ANSYS Workbench. Bogie frame loads, static strengths and dynamic characteristics of the frame under different conditions (straight, curve, braking and abnormal) were calculated based on its strength and design standards. Results: According to the requirement stress and dynamics standard, the maximum stress of the bogie frame was observed to be in the allowable stress value of the frame material, and the dynamic performance of the bogie model meets the design standards. Conclusion: The structural strength of the proposed bogie frame is reasonable, and the static strength and dynamic characteristics of the proposed bogie model are in accordance with the design requirements of the railway vehicle.

Dynamic Responses of the Metro Train’s Bogie Frames: Field Tests and Data Analysis

This paper focuses on the dynamic characteristics of the metro train’s bogie frames based on the field test data. The acceleration signals of both motor bogie frame and trailer bogie frame of a standard B-type metro train were measured. Running tests on the Metro line 21 of Guangzhou (China) were carried out. The acquired acceleration signals of bogie frames were analyzed through several methods to identify the dynamic characteristics of the motor and trailer bogies in the time-frequency domain. The spectral analysis and time-frequency representations show that noise components exist in the high-frequency domain of the original signal, especially for the acceleration signal of the motor bogie frame. Then, the soft thresholding process and discrete wavelet transform decomposition process are conducted to obtain a denoised version of the original signals in the time-frequency domain. The vibration frequency domain and energy distribution of bogie frames under different train speeds are analyzed. The track irregularity wavelength of the metro line is calculated and analyzed based on the measured bogie frames’ acceleration signals. The dynamic characteristics of the metro train’s bogie frames in this paper can be adopted as a reference in the track diagnosis of the elevated metro line.

Estimating load spectra probability distributions of train bogie frames by the diffusion-based kernel density method

The load spectra of a train bogie frame are used for bogie frame design, simulated fatigue testing and reliability evaluation and fatigue life prediction, however, modelling the bogie load spectrum is one of the most challenging tasks in this field. In this paper, diffusion-based kernel density estimation (DKDE) is used to obtain the load spectra distributions of train bogie frames. A full-scale B-type subway motor bogie and a full-scale high-speed EMU trailer bogie are analysed. DKDE, Gaussian kernel density estimation (GKDE) and parametric estimation are used to fit the distributions of the loads. Goodness-of-fit tests suggest that the distributions obtained by DKDE are close to the actual distributions. Fatigue damage are calculated to evaluate the distributions estimated by DKDE and GKDE. From the distributions obtained by DKDE, reasonable maximum load values and reasonable extrapolated load spectra are deduced.

Aerodynamic Noise Separation of an EMU Trailer Bogie Area Using Train Operation Tests

The operation transfer path analysis (OTPA) technique was used to measure the vibration and noise transfer coefficient functions of wheel‐rail noise and radiated noise from an electric multiple unit (EMU) train (high‐speed train in China) trailer bogie structure to the central area of the trailer bogie for a train running at speeds of 0–5 km/h. By applying these transfer coefficient functions to the noise analysis of high‐speed train operation, the contributions of wheel‐rail noise and frame‐radiated noise to the noise of the bogie area at high speeds are obtained, and the aerodynamic noise is separated from the total noise, providing a reference for vibration damping and noise reduction in high‐speed trains. Analysis of test data shows that, in the central area of the trailer bogie of high‐speed trains, the low‐frequency noise mainly comes from the structural radiated noise of the bogie, and the mid‐ to high‐frequency noise is primarily due to aerodynamic noise. In addition, when an EMU train operates at speeds below 250 km/h, the noise in the central area of the trailer bogie is primarily caused by the structural radiated noise. When the operating speed is higher than 250 km/h, the noise in the central area of the trailer bogie is mainly due to aerodynamic noise, and the aerodynamic noise contribution increases with increase in speed.

EN 규격에 기반한 도시철도차량 차축의 경량화

Weight reduction of a railway axle, which is one of heaviest parts in an urban railway vehicle, is discussed in this paper. A wheelset of a railway vehicle is very important with regard to railway safety, and its structural strength should always be considered when attempting to reduce the railway axle weight. In this work, the weight of the axles of a trailer bogie and a motor bogie of the Korean EMU was reduced by replacing solid axles with hollow axles. On the basis of the EN standard for railway axle design, the strength of existing solid axles was analyzed and the required bore size of a hollow axle was determined. It is shown that the weight of the concurrent axle of the Korean EMU can be reduced by up to 20% with a very small decrease in the structural strength. Finite element analyses were also carried out to verify the design result for lightweight hollow axles.

Evaluation of wheel dampers on an intercity train

Pass-by noise from high-speed trains is one important area that has to be handled in all new train projects. For the new line between Oslo and the Gardemoen Airport which opened in 1998, very stringent requirements were set out regarding external noise. To reach the target it was decided that the train should be equipped with wheel dampers. Two different types of wheel dampers were used on the train; a ring damper was mounted on the wheels of the driven bogies, whilst plate dampers divided into tuned absorber fins were mounted on the wheels of the trailer bogies. During the type testing of the Airport Express Train, additional measurements were performed in order to evaluate the acoustic effect of the plate wheel dampers. Two test series were performed with the same train set; first with the train in standard configuration and secondly with the wheel dampers removed from the second and third bogie. The external noise was measured at 5 and 25 m distance from the centre of the track at speeds ranging from 80 to 200 km/h. The third-octave filtered time histories were analyzed to calculate the effect of the wheel dampers. As expected, there was a significant reduction of 4–6 dB at frequencies above 2000 Hz, but there was also a reduction of 2 dB for frequencies as low as 800 Hz. This reduction was also found in the parts of the time histories when the rail should be dominating. This implies that the wheel dampers also reduce the rail noise. The total rolling noise reduction for the trailer bogie was 3 dB at 200 km/h and 1 dB at 80 km/h. From comparison with TWINS-calculated sound power levels it was estimated that the wheel noise would be reduced by 5 dB and the rail noise would be reduced by 1 dB at 200 km/h.