International Journal of COMADEM https://apscience.org/comadem/index.php/comadem <div class="additional_content"> <div class="entry-content"> <p>This peer-reviewed internationally acclaimed professional-cum-learned journal was launched in 1998 to meet the needs of the global condition monitoring community. The International editorial board consists of prominent academics, consultants, engineers, scientists, technologists and management specialists representing a wide sector of the economy. This leading edge technology management journal is interdisciplinary based and is totally dedicated to:</p> <ul> <li class="show">Industrial Asset Management</li> <li class="show">Advances in Maintenance Engineering and Management</li> <li class="show">Standardization</li> <li class="show">Industrial Case Studies</li> <li class="show">Integrated Vehicle Health Management</li> <li class="show">Advances in Systems Failure Diagnosis and Prognosis</li> <li class="show">Big Data Management</li> <li class="show">Advanced Sensor Technology</li> <li class="show">Health &amp; Safety</li> <li class="show">Intelligent Manufacturing</li> <li class="show">Risk Management</li> <li class="show">Technology Management</li> <li class="show">Industrial Logistics</li> <li class="show">Industrial Tribology</li> <li class="show">Bio-medical Engineering</li> <li class="show">Structural health Monitoring</li> <li class="show">Advanced Signal Processing</li> <li class="show">Machinery/Process Health Monitoring</li> <li class="show">Environmental Management</li> <li class="show">RCM</li> <li class="show">TQM</li> </ul> </div> </div> <p>The Journal covers peer-reviewed technical papers, industrial case studies, best practice tutorials, critical overviews, technical literature abstracts, latest news, conferences proceedings, book reviews, etc.</p> <p>This journal is distributed worldwide. It is indexed in INSPEC, Shock &amp; Vibration Digest, Current Contents, NASA Center for Aerospace Information, British Library etc.</p> Comadem International en-US International Journal of COMADEM 1363-7681 <p>Author(s) by submitting the manuscript to the International Journal of COMADEM agree to transfer the rights to COMADEM International UK with some exceptions as described in <a href="copyrights">COPYRIGHT TRANSFER AGREEMENT</a> available <a href="copyrights">here</a>.</p> Contents https://apscience.org/comadem/index.php/comadem/article/view/160 Contents Contents Contents Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 An approach to evaluate wheel-rail match properties considering the flexibility of ballastless track: Comparison of rigid and flexible track models in wheel-rail profile matching https://apscience.org/comadem/index.php/comadem/article/view/151 <p>Many different wheel/rail profiles are used in the China high-speed railway, and vehicle operation safety and comfort will decrease if the inappropriate wheel-rail profile pair is used. To solve the problem of estimating the wheel-rail match, many numerical models, including vehicle system dynamic models and wheel-rail rolling contact models, have been established to analyse the wheel-rail dynamic responses. Both methods have less consideration of the <br />flexibility and vibration characteristics of ballastless track, leading to deviations in the calculation of middle and high frequency vibration. This paper proposes a vehicle-flexible track coupling model and compares it with the vehicle dynamic model (vehicle-rigid track model). In the rigid track model, only the track irregularities are considered in the track module; the vibrations and deformations of rails, track slab and the foundation are considered in the flexible track model. Taking Chinese CRH3 series wheel profile S1002CN and rail profile CHN60 as examples and considering different track excitations, the two models are compared. The wheel-rail interaction forces, wheel-rail wear depths, wear volumes and vehicle accelerations are chosen as analysis indices for the comparative study.</p><p>The results show that the wheel-rail forces of the flexible track model are larger than the rigid track model in the frequency range from 70 to 120Hz, while they decrease obviously in the frequency range above 150Hz. The differences in wear depths and volumes between the two models exceed 10%. Therefore, the flexible track model should be considered when studying the match properties of different wheel-rail pairs.</p> Bolun An Liang Gao Tao Xin Jing Lin Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Velocity field detection method using the elastic wave of a damaged bolster https://apscience.org/comadem/index.php/comadem/article/view/152 The paper aims to solve the technical problem of damage detection of an EMU body bolster. It establishes an elastic wave and elastic modulus mathematical model using the elastic body wave differential equation. A mathematical model of damage level and elastic wave velocity is established using damage mechanics theory. The Ultrasonic Tomography Technique and the Algebraic Reconstruction Technique (ART) are used to detect the discrete wave velocity field in the bolster testing area, thus completing the nephogram analysis of the whole bolster damage state. Taking the area between actual bolster positioning and support location as a test example, the paper finds that the elastic wave velocity field and the damage state distribution of the bolster are consistent with the actual state of the EMU body bolster. Dong-ming Hou Guan-ji Xu Lin Shen Jin-qiang Liu Han Zhang Hong-yuan Qi Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Identification of span of Multi-span Simply Supported Girders by the Longitudinal Level Waveforms https://apscience.org/comadem/index.php/comadem/article/view/153 In high-speed railways, the periodic component of longitudinal level on the top surface of the track can be observed for multi-span simply supported girders. To monitor this component, the paper proposes a method to determine the locating position of simply supported girders using longitudinal level waveforms. The method first applies time-frequency analysis to determine the locating position of simply supported girder bridges in the longitudinal level <br />waveform. Then it adopts a local minimum detection strategy to identify the locating position of the girders. The method is evaluated using the longitudinal level data of a 100km high-speed railway in China; the results show good locating performance. Bo Zhang Xiubo Liu Jing Lin Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Dynamic analysis and detection of wheel polygonization on high-speed trains based on axle box vibrations https://apscience.org/comadem/index.php/comadem/article/view/154 Wheel polygonization of high-speed trains has received considerable attention because it deteriorates the dynamic interaction of wheel and rail and intensifies the vibration and noise of the vehicle-track system. The dynamics of the vehicle system, the excitation of track irregularities, and the movement and deformation of wheelsets introduce extensive coupling and complexity to the vibration response of high-speed trains, especially in medium and high-frequency ranges. The paper establishes a multi-body dynamics model of a vehicle with flexible wheelsets using finite element methods; simulations are performed to investigate the vibration characteristics of wheel polygonization. The paper measures the acceleration of axle boxes to monitor and detect wheel polygonization, adopting the complete ensemble empirical mode decomposition with adaptive noise (CEEMDAN) to decompose the signal into <br />several intrinsic mode functions (IMFs). The improved Hilbert-Huang transform (HHT) is performed, and the time-frequency spectrum is plotted to visually indicate the characteristic frequency of polygonization. Next, the Kullback-Leibler divergency is used to select the effective IMF; the mean frequency of the selected component is obtained to detect wheel polygonization and the corresponding order. Finally, simulations and field tests are performed to verify the effectiveness, accuracy, and robustness of the proposed method in a complex vibration environment. Xiaoyue Qi Yuanchen Zeng Dongli Song Weihua Zhang Bin Zhou Mingyuan Xie Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Research on Predicting the Tamping Cycle of Heavy Haul Railway for Different Large Machine Tamping Modes https://apscience.org/comadem/index.php/comadem/article/view/155 An important research direction for heavy haul railway maintenance is to use track condition inspection data. This paper analyses the MTQI (Machine Tamping Quality Index) before and after tamping for different large machine..tamping modes (tamping machine type, single/double tamping, stabilizing vehicle, line type) using inspection and repair data and establishes a tamping effect model. A prediction model of the MTQI index using gross weight is established with grey GM (1, 1) prediction technology. When combined with the tamping effect model, it can be used to compare and select maintenance modes and predict the tamping cycle under different tamping modes. Using an example from a heavy haul railway, the paper shows the proposed prediction model will help the track management department select the best tamping maintenance mode. It can provide a scientific and economic decision-making plan for tamping maintenance and facilitate preventive maintenance. Jianjun Qu Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Performance analysis of slab track structures on long-span high-speed railway bridge https://apscience.org/comadem/index.php/comadem/article/view/156 Long-span railway bridges tend to bear large deformation under complex loads. The performance of slab track structures on the long-span bridge is not clear. To research the performance, a FE model is established. The most unfavourable upward and downward deformation of the bridge under complex loads are considered. The stresses of the slab, self-compacting concrete, and base slab are calculated and analysed. Curvature of bridge deformation under the most unfavourable condition is calculated. The relationship of track stress and bridge deformation curvature is discussed. To reduce the stress of the slab track <br />structure, a rubber mat is designed to be installed between track structures. The results can be used as a reference for railway track design and maintenance workers. Yu Ding Tao Xin Pengsong Wang Hailong Huo Peng Chen Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Monitoring and Analysis of Dynamic Behaviour of High-Speed Trains in Long-Term Service using an Unattended Test System https://apscience.org/comadem/index.php/comadem/article/view/157 Dynamic behaviour and its evolution are concerns for those operating high-speed trains. In this paper, a cloud server is applied to establish a connection between the vehicle-mounted equipment and users to decrease the influence of network instability. To ensure the accuracy and consistency of data transmission, MQTT (Message Queue Telemetry Transport) protocol is used to transfer data measured from the vehicle. The paper discovers the vibration <br />transfer characteristic and the evolution of the dynamic behaviour of several types of high-speed trains, along with wheel wear under several operation conditions, over time. The turbulence caused by high-order wheel polygonalization formed during long-term service, which cannot be weakened by the suspended system sufficiently, is harmful to the ride quality of high-speed trains. The results confirm the operational reliability of the high-speed trains in China and provide useful references for the optimisation and maintenance of high-speed trains. Xin Ding Xingqiao Ai Yongsheng Li Jintian Wang Zhendong Liu Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Field measurement and vibration reduction evaluation of rubber floating slab track on metro lines https://apscience.org/comadem/index.php/comadem/article/view/162 Rubber floating slab track (RFST) is a vibration reduction track structure widely adopted in metro lines because the environmental vibration problems induced by urban rail transit are getting worse. Due to the complexity of rubber materials and the uncertainty of environmental factors, there may be some differences in the vibration reduction effects of RFST between its design and service phase. To monitor and evaluate realistic vibration reduction effects of RFST, field measurements are carried out on four typical cross sections in a tunnel of a metro line. Vertical accelerations of rail, track slab, and tunnel wall are collected<br />for straight-line (SL) and curved-line (CL) segments. The measurement data are analysed and compared between common track and RFST. Time-domain and frequency-domain analysis are carried out, and Z weighted vibration acceleration level on tunnel wall is calculated. The field measurement results show the vibration reduction effects of RFST are remarkable. It can hinder the transmission of vibration from the track to the tunnel. The results can provide a reference for the application of RFST in metro lines. Pengsong Wang Tao Xin Yu Ding Sen Wang Xiaoli Zheng Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3 Early fault signal processing for an EMU rolling bearing based on acoustic emission https://apscience.org/comadem/index.php/comadem/article/view/163 The rolling bearing is an important part between the wheel axle and the bogie frame of Electric Multiple Units (EMU), and the running state directly affects the vehicle stability. Therefore, early fault diagnosis is the technical guarantee of the safe operation of the EMU. At present, as temperature and vibration detection technology cannot identify early faults, this paper proposes a signal processing method based on acoustic emissions. LMS adaptive filter technology is used to filter the acoustic emission original waveform stream to improve the signal-to-noise ratio of the fault signal. The envelope demodulation method is used to extract the low frequency fault signal by means of the cubic spline interpolation Method; then, the power spectrum of the low frequency fault signal is analysed. Taking a natural small defect in an EMU bearing as an example, the acoustic emission signal is analysed. The results show that the proposed method could identify early faults in rolling bearings under different operating EUM speeds. Dong-ming Hou Meng Xu Guan-ji Xu Lin Shen Hong-yuan Qi Copyright (c) 2019 International Journal of COMADEM 2019-08-27 2019-08-27 22 3