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SAE International Journal of Vehicle Dynamics Stability and NVH
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Detection Method for Cavity Defects in Ballastless Track Structures of High-Speed Railways Based on Air-Coupled Ultrasonic Lamb Waves

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Shanghai University of Engineering and Technology, China-Zhu Wenfa, Shao Wei, Chen Xingjie, Meng Xiangzhen
Shanghai University, China-Zhang Haiyan
  • Journal Article
  • 10-03-02-0010
Published 2019-07-02 by SAE International in United States
This study proposes a method for the rapid detection and location of cavity defects in ballastless track structures of high-speed railways in service. First, the propagation of air-coupled ultrasonic Lamb waves in the ballastless track structure is studied. Theoretical calculation results show that the ultrasonic Lamb wave group velocity of the A2 mode in the track plate is 4000 m/s. Then, the excitation and reception methods of the air-coupled ultrasound are studied. Theoretical and experimental results show that the A2 mode Lamb wave can be generated by the 3.8° oblique incidence of the ballastless track structure. Finally, an experimental system for air-coupled ultrasonic testing is constructed. A pair of air-coupled ultrasonic probes is used to provide excitation and reception Lamb wave signals at an inclined angle of 3.8°, 20 mm away from the surface of the track plate, and 40 mm/step along the scanning direction. Experimental data indicate that interaction between the Lamb wave and cavity conforms to the energy leakage principle, and the amplitude of the Lamb wave increases with the increase in cavity…
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Impact of Dynamic Characteristics of Wheel-Rail Coupling on Rail Corrugation

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Shanghai University of Engineering Science, China-Xiaogang Gao, Anbin Wang, Xiaohan Gu, Wei Li
  • Journal Article
  • 10-03-02-0009
Published 2019-07-02 by SAE International in United States
To gain a better understanding of the characteristics of corrugation, including the development and propagation of corrugation, and impact of vehicle and track dynamics, a computational model was established, taking into account the nonlinearity of vehicle-track coupling. The model assumes a fixed train speed of 300 km/h and accounts for vertical interaction force components and rail wear effect. Site measurements were used to validate the numerical model. Computational results show that (1) Wheel polygonalisation corresponding to excitation frequency of 545-572 Hz was mainly attributed to track irregularity and uneven stiffness of under-rail supports, which in turn leads to vibration modes of the bogie and axle system in the frequency range of 500-600 Hz, aggregating wheel wear. (2) The peak response frequency of rail of the non-ballasted track coincides with the excitation frequency of wheel-rail coupling; the resonance results in larger wear amplitude of the rail. The track lateral pinned-pinned frequency at 540 Hz contributes to the propagation of rail corrugation. (3) With wheel-rail contact friction coefficient of 0.3, simulation results of track lateral pinned-pinned frequency…
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CFD and Wind Tunnel Analysis of the Drag on a Human-Powered Vehicle Designed for a Speed Record Attempt

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Cranfield University, UK-Julien Lefieux, Cathal Moloney
National Flying Laboratory Centre, UK-Christopher Bennett, Nicholas Lawson
  • Journal Article
  • 10-03-02-0008
Published 2019-06-07 by SAE International in United States
A computational fluid dynamics (CFD) and wind tunnel investigation of a human powered vehicle (HPV), designed by the Velo Racing Team at Ostfalia University, is undertaken to analyse the Eco-body’s drag efficiency. Aimed at competing in a high profile HPV speed record competition, the vehicle’s aerodynamic efficiency is shown to compare well with successful recent eco-body designs. Despite several limitations, newly obtained wind tunnel data shows that the corresponding CFD simulations offer an effective tool for analysing and refining the HPV design. It is shown that, in particular, the design of the rear wheel fairings, as well as the ride height of the vehicle, may be optimised further. In addition, refinements to the CFD and wind tunnel methodologies are recommended to help correlation.
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A Review on Physical Mechanisms of Tire-Pavement Interaction Noise

SAE International Journal of Vehicle Dynamics, Stability, and NVH

Maxxis International, USA-Tan Li
  • Journal Article
  • 10-03-02-0007
Published 2019-05-16 by SAE International in United States
Tire-pavement interaction noise (TPIN) dominates for passenger cars above 40 km/h and trucks above 70 km/h. Numerous studies have attempted to uncover and distinguish the basic mechanisms of TPIN. However, intense debate is still ongoing about the validity of these mechanisms. In this work, the physical mechanisms proposed in the literature were reviewed and divided into three categories: generation mechanisms, amplification mechanisms, and attenuation mechanisms. The purpose of this article is to gather the published general opinions for further open discussions.
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Uncertainty Analysis of High-Frequency Noise in Battery Electric Vehicle Based on Interval Model

SAE International Journal of Vehicle Dynamics, Stability, and NVH

China Automotive Technology and Research Center Co., Ltd, China-Cansong Gu, Yaodong Hao
Jilin University, China-Junhong Dong, Fangwu Ma
  • Journal Article
  • 10-03-02-0006
Published 2019-02-01 by SAE International in United States
The high-frequency noise issue is one of the most significant noise, vibration, and harshness problems, particularly in battery electric vehicles (BEVs). The sound package treatment is one of the most important approaches toward solving this problem. Owing to the limitations imposed by manufacturing error, assembly error, and the operating conditions, there is often a big difference between the actual values and the design values of the sound package components. Therefore, the sound package parameters include greater uncertainties. In this article, an uncertainty analysis method for BEV interior noise was developed based on an interval model to investigate the effect of sound package uncertainty on the interior noise of a BEV. An interval perturbation method was formulated to compute the uncertainty of the BEV’s interior noise. The sound absorption coefficient and transmission loss of the sound package were obtained through tests, and a statistical energy analysis model of the BEV was established. The acoustic loads of the BEV were tested and the interior noise of the cabin was analyzed under certain working conditions. Uncertain parameters were…
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