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作者： YAN Bao-yong CAO Liu Chongqing Research Institute of China Coal Technology and Engineering Group State Key Lab. of Gas Disaster Monitoring and Control as well as Emergency Technology Southwest Petroleum University

In the coal mine gas drainage,the gas drainage in gob has a dominant position. According to different stages of the production,the mining areas are divided into the gob,the old one and the abandoned one. Gas drainage of gob has an important influence on mining propulsion. Through comparative analysis of various drainage methods,exclusive tunnel pumping method will gradually be eliminated with the promotion of directional drilling technique in the roof construction and application. Large diameter roof horizontal directional long drill hole will replace the roof pumping lane,the roof short drilling,and gob buried drainage pipe. Some old gob has begun experiments of ground wells. A well used repeatedly can maximize the drainage of gas in the future,along with one-well three-purpose technology continues to be mature. The true sense of the abandoned mine gas drainage is still blank in China,according to the experience of foreign pumping,the ground large diameter bored construction will become a reasonable choice in obsolete mine gob gas drainage.

关键词： gob gas drainage ground borehole

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Analysis of Vibration Monitoring Data of Flexible Suspension Lifting Structure Based on Time-Varying Theory

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SENSORS 2020年第22期20卷 6586.-6586.页

作者： Peng, Qifeng Xu, Peng Yuan, Hong Ma, Haixia Xue, Jianghong He, Zhenya Li, Shanqing Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Sch Mech & Construct Engn Guangzhou 510632 Peoples R China South China Univ Technol Guangzhou Coll Sch Elect Engn Guangzhou 510800 Peoples R China South China Univ Technol Guangdong Prov Key Lab Precis Equipment & Mfg Tec Guangzhou 510640 Peoples R China

An elevator is a typical flexible lifting machine. In order to monitor the vibration of elevator structure, the vibration characteristics of an elevator with a traction ratio of 1:1 has been tested experimentally. Sensors were arranged on the platform frame, car roof, and hoist rope to test the vibrations of the elevator in both ascending and descending conditions. The transverse, longitudinal, and coupled transverse-longitudinal vibrations were compared and analyzed. Further, the short-time Fourier transform (STFT) method was used to examine the power spectral density (PSD) of the test results, and the main frequency distribution and influencing factors of the vibration of elevator components were investigated. The results revealed that the transverse and longitudinal vibrations of the platform frame were low-frequency vibrations, which was attributed to the elastic interaction between the platform frame and the car frame. The form and amplitude of longitudinal vibration of the car frame were basically consistent with those of the platform frame, but PSD of the transverse vibration had an obvious peak in the high-frequency region. The transverse and longitudinal vibration frequencies of the hoist rope were higher. Furthermore, the peak PSD value of transverse vibration of the hoist rope was 421 times larger than that of the car frame, so a small disturbance at the end of the rope could lead to a huge disturbance in the center of the rope. Overall, this study provides useful insights on designing an elevator monitoring sensor and relevant data processing.

关键词： machine dynamics non-linear vibration random vibration sensors and actuators structural dynamics and control

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The physics-based deterministic scenarios for earthquake hazards and losses of the Zhujiangkou fault in southern China

npj Natural Hazards

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npj Natural Hazards 2025年第1期2卷 1-13页

作者： Yilong Li Ming Wang Kai Liu Houyun Yu Zhenguo Zhang Wei Zhang Xiaofei Chen Xiuwei Ye Joint International Research Laboratory of Catastrophe Simulation and Systemic Risk Governance Beijing Normal University Zhuhai China School of National Safety and Emergency Management Beijing Normal University Zhuhai China Department of Earth and Space Sciences Southern University of Science and Technology Shenzhen China School of National Safety and Emergency Management Beijing Normal University Beijing China Guangdong Provincial Key Laboratory of Geophysical High-resolution Imaging Technology Southern University of Science and Technology Shenzhen China China Earthquake Administration Key Laboratory of Earthquake Monitoring and Disaster Mitigation Technology Guangdong Earthquake Agency Guangzhou China Guangdong Science and Technology Collaborative Innovation Center for Earthquake Prevention and Disaster Mitigation Guangzhou China Key Laboratory of Disaster Forecast and Control in Engineering of the Ministry of Education Urban Earthquake Safety Laboratory Guangzhou China

Dynamic rupture directivity significantly impacts earthquake hazard and loss assessments; yet, it is often overlooked, leading to uncertainties. We developed high-resolution, broadband, deterministic scenarios for earthquake hazards and losses of the Zhujiangkou Fault (ZF) in the Guangdong-Hong Kong-Macao Greater Bay Area of southern China. The calculations cover the entire physical process from fault dynamic rupture through strong ground motion propagation to quantitative loss estimations. We fully incorporate the real 3D physical fields, including fault structure, regional stress, friction conditions, inhomogeneous velocity, and topography. Results revealed higher earthquake hazards and losses triggered by the northwestern ZF segment, affecting Hong Kong, Shenzhen, Dongguan, Macao, and Guangzhou. The rupture directivity effect, driven by seismic wave interferences in forward propagation, leads to stark differences in hazards and losses across urban agglomerations, even under similar fault conditions. These findings help enhance the precision of earthquake risk assessments and provide practical approaches for disaster prevention.

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Nonlinear dynamic behavior of single-layer graphene under uniformly distributed loads

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COMPOSITES PART B-engineering 2019年 165卷 473-490页

作者： Yan, J. W. Lai, S. K. He, L. H. Jinan Univ Guangdong Higher Educ Inst Key Lab Prod Packaging & Logist Zhuhai Guangdong Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou Guangdong Peoples R China Hong Kong Polytech Univ Dept Civil & Environm Engn Hung Hom Kowloon Hong Kong Peoples R China Hong Kong Polytech Univ Shenzhen Res Inst Shenzhen Peoples R China Univ Sci & Technol China Dept Modern Mech CAS Key Lab Mech Behav & Design Mat Hefei Anhui Peoples R China

An atomistic-continuum multiscale approach is used to simulate the nonlinear dynamic behavior of simply supported single layer graphene sheets subject to a uniformly distributed out-of-plane load. The dynamic equation of motion is derived and solved by the Newmark-beta method. The evolution of surface morphology and the nonlinear effects in terms of geometrical and material nonlinearities can be captured by iteratively updating the system stiffness. It is found that the natural frequencies of simply-supported graphene sheets almost remain constant when the external load is in a small range. The present solutions are in good agreement with those results obtained from the linear vibration analysis by a semi-analytical method. As the applied load increases continuously, this gives rise to an elongation of graphene to increase the natural frequency. Based on the numerical approach, the surface morphology evolution of graphene can be visualized and explored.

关键词： Graphene Nonlinear dynamic behavior Atomistic-continuum multiscale approach Natural frequency Surface morphology evolution

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Comparison of regularization methods for moving force identification with ill-posed problems

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JOURNAL OF SOUND AND VIBRATION 2020年 478卷 115349-000页

作者： Chen, Zhen Chan, Tommy H. T. Yu, Ling North China Univ Water Resources & Elect Power Sch Civil Engn & Commun Zhengzhou 450045 Peoples R China Queensland Univ Technol QUT Sch Civil & Environm Engn Brisbane Qld 4000 Australia Jinan Univ Sch Mech & Construct Engn MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China

Four new methods have been developed to overcome the ill-posed problems inherently existing in moving force identification (MFI) in previous studies. This paper is an extension of the work to evaluate the overall performance of these presented methods by numerical simulations and experiment verifications in laboratory. A simply-supported bridge and two types of moving forces are adopted to evaluate the identification accuracy and ill-posed immunity of these new approaches. Bending moment and acceleration responses are measured when the time-varying forces moving across the bridge deck at constant speed. Numerical simulations of both uniaxial and biaxial forces include 12 cases, which are used to compare the identification accuracy and ill-posed immunity of these methods in detail. Finally, a hinge supported steel beam model and a vehicle model were designed and fabricated in laboratory. Then a series of experimental studies on MFI with these four methods are performed in laboratory. Both numerical and experimental results show that these four approaches can accurately identify moving forces with strong robustness and ill-posed immunity. Moreover, the truncated generalized singular value decomposition (TGSVD) method has higher identification accuracy than the piecewise polynomial truncated singular value decomposition (PP-TSVD) method, and the modified preconditioned conjugate gradient (M-PCG) method has higher identification efficiency than the pre-conditioned least square QR-factorization (PLSQR) method. To summarize, if the first goal in MFI is to improve the identification accuracy, the TGSVD method is recommended due to its high identification accuracy and stability in different cases. If the first goal in MFI is to improve the identification efficiency, the M-PCG method is recommended due to its high identification efficiency and easy to determine the optimal number of iterations. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： Moving force identification Ill-posed immunity Identification accuracy Identification efficiency Numerical simulations Experiment verifications Regularization

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A novel MOALO-based algorithm for structural damage detection 7

A novel MOALO-based algorithm for structural damage detectio...

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7th Asia-Pacific Workshop on Structural Health Monitoring, APWSHM 2018

作者： Chen, C.B. Yu, L. School of Mechanics and Construction Engineering Jinan University Guangzhou510632 China MOE Key Lab of Disaster Forecast and Control in Engineering Jinan University Guangzhou China

ISBN: (纸本)9783000603594

Structural damage detection (SDD) is the first-type inverse problem in structural dynamics, and it is usually converted to a kind of constrained optimization problem in mathematics. Exploring a highly accurate and robust solution to the SDD problem is a challenging task in the field of structural health monitoring (SHM). In this study, a novel SDD method is proposed based on multi-objective ant lion optimizer (MOALO) algorithm, in which multi-objective functions are defined for the typical SDD inverse problem based on the model updating theory. The modal parameters, such as natural frequencies and mode shapes, are adopted into the objective functions whilst considering weighted coefficients corresponding to different modal parameters at the same time. The weighted strategy and sparse regularization are also taken into consideration for accurate SDD results with good robustness to noise. All illustrated results show that the proposed MOALO method is able to accurately locate and quantify damage of structures, which provides a potential SDD tool for real structures onsite. © APWSHM 2018. All rights reserved.

关键词： Inverse problems

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Mathematical modelling of microtubule-tau protein transients: Insights into the superior mechanical behavior of axon

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APPLIED MATHEMATICAL MODELLING 2019年 71卷 452-466页

作者： Wu, Jiayu Yuan, Hong Li, Long-yuan Li, Bing Fan, Kunjie Li, Shanqing Lee, Kin-Nam Jinan Univ Inst Appl Mech MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China Univ Plymouth Sch Engn Plymouth PL4 8AA Devon England Imperial Coll London Blackett Lab South Kensington Campus London SW7 2AZ England Univ Kent Medway Sch Pharm Chatham ME4 4TB Kent England

Axons with staggered microtubules cross-linked by tau protein possess a remarkable mechanical balance of high specific stiffness and toughness. Owing to their viscoelastic nature, axons exhibit stress rate-dependent mechanical behavior, which is relevant to their selective vulnerability to damage in traumatic brain injury. A Kelvin-Voigt viscoelastic shear lag model is developed to elucidate the mechanical responses of axons under transient tensile force. Analytical closed-form expressions are derived to characterize the relative sliding, stress transfer and failure mechanism between microtubule and tau protein while the axon is stretched transiently. The results from the theoretical solutions elucidate how the MT-tau interface length and stress rate affect the mechanical responses of axon. It is found that axonal failure mechanism may be different under different loading conditions. Long microtubules are more vulnerable to rupture at high stress rate, yet short microtubules are likely to detach from microtubule bundles under large deformations. In the view of multilevel failure of axon, it is illustrated how the vulnerable axons protect themselves from overall damage, and how the axon can simultaneously achieve an outstanding mechanical balance of high specific stiffness and toughness. (C) 2019 Elsevier Inc. All rights reserved.

关键词： Staggered composite Biocomposite Shear lag model Kelvin-Voigt viscoelastic model Traumatic brain injury

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Mechanistic Understanding of the Corrosion Behaviors of AZ31 Finished by Wire Electric Discharge Machining

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JOURNAL OF THE ELECTROCHEMICAL SOCIETY 2021年第7期168卷 071507-071507页

作者： Qiu, Youmin Chen, Lianxi Yang, Junjie Zeng, Dahai Liu, Hui Han, Jiaping Li, Qi Li, Jianwei Tu, Xiaohui Li, Wei Jinan Univ Inst Adv Wear & Corros Resistant & Funct Mat Guangzhou 510632 Peoples R China Foshan Univ Sch Mat Sci & Hydrogen Energy Foshan 528000 Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Peoples R China Songshan Lake Mat Lab Dongguan Guangdong Peoples R China Panzhihua Univ Dept Vanadium & Titanium Panzhihua 617000 Sichuan Peoples R China Harbin Inst Technol Sch Mechatron Engn Harbin 150001 Peoples R China Beijing Hangxing Machinery Manufacture Ltd Corp Beijing 100013 Peoples R China

Metallic contamination that occurs during machining is extremely hard to avoid, which may cause an irretrievable effect on the performance of materials. Unfortunately, this point is chronically neglected in practice. The present study focused on investigating the influence of wire electric discharge machining (WEDM), one of the most common techniques for magnesium implant manufacturing, on the morphology and corrosion behaviors of AZ31. The results show that the surface roughness increased after machining due to the presence of overlapped craters and scattered micro-cracks. Deposition of tool electrode materials was found throughout the recast layer in the form of Cu-rich particles (CuRPs), and increasing the energy input escalates this deposition process. The corrosion resistance of WEDM machined AZ31 was significantly deteriorated due to the galvanic coupling between CuRPs and Mg matrix. The corrosion mechanism of AZ31 alloy with CuRPs deposition was elucidated.

关键词： AZ31 magnesium alloy Wire electrical discharge machining (WEDM) Corrosion behaviors Cu impurity Mirco-galvanic corrosion

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Identification of vehicle axle loads from bridge responses using preconditioned least square QR-factorization algorithm

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MECHANICAL SYSTEMS AND SIGNAL PROCESSING 2019年 128卷 479-496页

作者： Chen, Zhen Chan, Tommy H. T. Nguyen, Andy Yu, Ling North China Univ Water Resources & Elect Power Sch Civil Engn & Commun 36 Beihuan Rd Zhengzhou 450045 Henan Peoples R China QUT Sch Civil Engn & Built Environm Brisbane Qld 4000 Australia USQ Sch Civil Engn Surveying Springfield Cent 4300 Australia Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

This paper develops a novel method for moving force identification (MFI) called preconditioned least square QR-factorization (PLSQR) method. The algorithm seeks to reduce the impact of identification errors caused by unknown noise. The biaxial moving forces travel on a simply supported bridge at three different speeds is used to generate numerical simulations to assess the effectiveness and applicability of the algorithm. Results indicate that the method is more robust towards ill-posed problem and has higher identification precision than the conventional time domain method (TDM). In addition, the robustness and ill-posed immunity of PLSQR are directly affected by two kinds of regularization parameters, namely, number of iterations j and regularization matrix L. Compared with the standard form of least square QR-factorization (LSQR), i.e., the regularization matrix L being the identity matrix I-n, the PLSQR with the optimal number of iterations j and regularization matrix L has many advantages on MFI and it is more suitable for field trials due to better adaptability with type of sensors and number of sensors. (C) 2019 Elsevier Ltd. All rights reserved.

关键词： Moving force identification Preconditioned least square QR-factorization Time domain method Regularization parameter Preconditioner

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Structural damage detection via adaptive dictionary learning and sparse representation of measured acceleration responses

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MEASUREMENT 2018年 128卷 377-387页

作者： Chen, Zepeng Pan, Chudong Yu, Ling Jinan Univ Sch Mech & Construct Engn Guangzhou 510632 Guangdong Peoples R China Jinan Univ MOE Key Lab Disaster Forecast & Control Engn Guangzhou 510632 Guangdong Peoples R China

Extracting damage-sensitive features from measured acceleration responses is still a big challenge in structural damage detection (SDD). In order to obtain the sparse representation of acceleration responses for damage identification, two dictionary learning methods and a damage indicator based on the change in mean sparsity (CMS) have been proposed in this paper. The first dictionary is empirical mode decomposition (EMD)-based dictionary generated by collecting a series of intrinsic mode functions (IMFs) while the second one is sparse coding (SC)-based dictionary learned by adaptively iterative optimization. The CMS is based on variation of a sparse features set. Numerical simulations on a simply-supported beam and on a 31-bar planar truss under different damage severities illustrate the effectiveness of the proposed methods for sparse representation and the capabilities of the defined CMS for damage indication. Comparative studies show that the SC-based dictionary outperforms the EMD-based dictionary in sparse representation. Moreover, a series of SDD experimental verifications on a simply-supported beam with a rectangular section in laboratory provide a further support to the proposed methods potentially using in-site acceleration measurements.

关键词： Structural damage detection (SDD) Sparse representation Empirical mode decomposition (EMD) Sparse coding (SC) Damage indicator

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