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Thermoelectric properties of polycrystalline（SnSe）1-x（AgSnSe2）x/2 alloys

Progress in Natural Science:Materials International 2022年第2期32卷 242-247页

作者： Long Jiang Weiwei Liu Lihong Han Hao Sun Yu Wang Yihua Zhang Haijun Wu State Key Laboratory for Performance and Structure Safety of Petroleum Tubular Goods and Equipment Materials CNPC Tubular Goods Research Institute MOE Key Laboratory for Nonequilibrium Synthesis and Modulation of Condensed Matter and State Key Laboratory for Mechanical Behavior of Materials Xi'an Jiaotong University School of Materials Science and Engineering Chang'an University

SnSe is considered as a thermoelectric material with great potential and advantages due to the record of high thermoelectric figure of merit（ZT） of 2.6 at 923 K in single ***,it is difficult to use single crystal SnSe in practice due to its poor mechanical properties and high manufacturing ***,the polycrystalline SnSe also is also not suitable for applications due to its much lower thermoelectric performance compared with single crystal ***,improving the thermoelectric properties of polycrystalline SnSe has become a hot research *** this paper,AgSnSe2doped into SnSe to increase the carrier density of the system and thus improve its thermoelectric *** is found that the addition of AgSnSe2can effectively improve the thermoelectric performance of polycrystalline SnSe.A peak ZT of 0.81 was obtained at 713 K for（SnSe）0.95（AgSnSe2）0.025,which is 305% higher than that of the undoped *** reveals that AgSnSe2-doped SnSe alloy may become a thermoelectric material system with great application potential and significance.

关键词： Thermoelectric materials SnSe AgSnSe2

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Modeling and experiment study of hydraulically damped rubber mount under larger amplitude excitation at low frequency

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Noise and Vibration Worldwide 2023年第1期54卷 31-43页

作者： Liao, Xin Chen, Lin Wang, Hu Pei, Xin School of Mechanical Engineering Shijiazhuang Tiedao University Shijiazhuang China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China School of Mechanical Engineering Southeast University Nanjing China 14th Institute of China Electronic Technology Corporation Nanjing China

To improve the ride comfort of the cab of construction machinery and reduce the harm of vibration to the driver, a nonlinear lumped parameter model of passive hydraulic damping rubber mount (PHDRM) is first proposed. The nonlinearity of multi-inertial tracks is fully considered. Then, the global FE (finite element) fluid-solid coupling model of the isolator is developed in ABAQUS. The multi-field coupling solution and a joint simulation mode are employed in this paper. Meanwhile, the rubber element and inertial track parameters are identified respectively. Finally, multiple sets of dynamic performance experiments are performed on the different PHDRM samples. The experiment results indicate that the simulation results for two modeling methods of the vibration isolation system are consistent with the experimental datum. The modeling approaches have both reliability and accuracy under larger amplitude excitation at low frequency. Furthermore, the effects of different rubber elements and inertial track of PHDRM on low-frequency dynamic characteristics under larger amplitude are investigated and discussed, respectively. The experimental outcomes also provide a practical reference value for nonlinear modeling method research and dynamic performance analysis of PHDRM with complex structures further. © The Author(s) 2023.

关键词： Rubber

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Localized space-tim e method of fundamental solutions for three-dimensional transient diffusion problem

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Acta Mechanica Sinica 2020年第5期36卷 1051-1057,I0002页

作者： L.Qiu J.Lin Q.-H.Qin W.Chen International Center for Simulation Software in Engineering and Sciences College of Mechanics and MaterialsHohai UniversityNanjing 210098China College of Engineering and Computer Science Australian National UniversityCanberraACT 2601Australia State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China State Key Laboratory of Acoustic Institute of AcousticsChinese Academy of SciencesBeijing 100190China

A localized space-time method of fundamental solutions(LSTMFS)is extended for solving three-dimensional transient diffusion problems in this *** interval segmentation in temporal direction is developed for the accurate simulation of long-time-dependent diffusion *** the LSTMFS,the whole space-time domain with nodes arranged i divided into a series of overlapping subdomains with a simple *** each subdomain,the conventional method of fundamental solutions is utilized and the coefficients associated with the considered domain can be explicitly *** calculating a combined sparse matrix system,the value at any node inside the space-time domain can be *** experi-ments demonstrate that high accuracy and efficiency can be simultaneously achieved via the LSTMFS,even for the problems defined on a long-time and quite complex computational domain.

关键词： Localized spacetime method of fundamental solutions Meshless method Long-time evolution Transient diffusion

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An improved autogram and its application in bearing fault diagnosis 11

An improved autogram and its application in bearing fault di...

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11th International Conference on Prognostics and system Health Management, PHM-Jinan 2020

作者： Liu, Wenpeng Yang, Shaopu Li, Qiang Liu, Yongqiang Beijing Jiaotong University School of Mechanical Electronic and Control Engineering Beijing China Shijiazhuang Tiedao University State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang China

ISBN: (纸本)9781728151816

Envelope analysis is one of the most advantageous methods in rolling element bearing (REB) diagnosis, but the determination of the informative frequency band (IFB) is always a huge challenge. In order to reduce the influence of discrete frequency components and strong background noise to choose IFB, a new improved Autogram is provided. Firstly, the Cepstrum pre-whitening (CPW) is taken as a preprocessing method to reduce the interference from discrete frequency components in the signal. Then, the Autogram is used to decompose the pre-whitening signal and the optimal IFB is selected for a further demodulation. The simulated signals and a set of experiment signals are taken to verify its validity. The results indicates that this method can successfully address the interference generated by discrete frequency and strong background noise, and effectively extract the weak fault features of bearing. © 2020 IEEE.

关键词： Failure analysis

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M-T Scheme for Predicting Effective Diffusion Coefficient of Chloride Ions in Cement-based Materials

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Journal of Wuhan University of Technology(Materials Science) 2020年第3期35卷 520-527页

作者： SUN Guowen ZHANG Jianjian ZHANG Lijuan CAO Tongning WANG Penshuo ZHANG Ying YAN Na State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShiji-azhuang 050043China School of Materials Science and Engineering Shijiazhuang TieDao UniversityShijiazhuang 050043China Foundational Subjects Department Shijiazhuang TieDao University SiFang CollegeShijiazhuang 051132China

To investigate the transport characteristics of chloride ions in cement-based materials, the Mori-Tanaka (M-T) prediction scheme of the effective diffusion coefficient in composites containing single-phase and multi-phase inclusions is systematically deduced based on the theory of composite mechanics and porous medium. The volume fraction, morphology and distribution of aggregates, as well as the interfacial transition zone (ITZ) are fully taken into consideration in this proposed model. The results show that the algorithm of M-T prediction scheme with high accuracy is relatively simple.

关键词： M-T scheme chloride ion effective diffusion coefficient cement-based materials ITZ

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An Extension of Correlated Kurtosis to Tunable Q-Factor Wavelet Transform in Fault Diagnosis of Rolling Element Bearings

An Extension of Correlated Kurtosis to Tunable Q-Factor Wave...

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2021 IEEE International Conference on Sensing, Diagnostics, Prognostics, and Control, SDPC 2021

作者： Zhao, Jing Li, Qiang Yang, Shaopu Liu, Yongqiang School of Mechanical Electronic and control Engineering Beijing Jiaotong University Beijing China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang China

ISBN: (纸本)9781665449762

In engineering practice, the type of rolling bearing failures are typical, and the fault signals are impulsive, which are influenced by the running status, the frequency component of the vibration signals become extremely complicated. Tunable Q-Factor wavelet transform (TQWT) method based on correlation kurtosis is proposed. This method decomposes the bearing fault signal into two different parts, high and low resonance components (HRC and LRC), basing on the different characteristics of signal oscillation. Then, calculating the correlation kurtosis of each decomposition layer of LRC to achieve signal reconstruction. Envelope demodulation analysis is performed on the reconstructed LRC . This method replaces the kurtosis index used in previous studies with correlated kurtosis index, which can effectively eliminate or weaken the influence of peak value interference. Finally, the simulation signals and wheelset bearing test signals are validated. The results show that this method can extract the features of bearing outer, inner and roller under strong background noise. © 2021 IEEE.

关键词： Wavelet transforms

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Dynamic mechanical characteristics and anti-thaw measures of warm frozen soil

Transportation Engineering

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Transportation engineering 2025年 20卷

作者： Liu, Jiankun Sun, Zhaohui Cui, Yinghui Hu, Tianfei Tai, Bowen School of Civil Engineering & State Key Laboratory for Tunnel Engineering Sun Yat-Sen University Guangzhou 519082 China Institute of Future Civil Engineering Sciences and Technology Chongqing Jiaotong University Chongqing 400074 China China State Railway Group Co. Ltd Beijing 100844 China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao University Shijiazhuang 050043 China State Key Laboratory of Cryospheric Science and Frozen Soil Engineering Northwest Institute of Eco-Environment and Resources Chinese Academy of Sciences Lanzhou 730000 China

Permafrost is widely distributed across the Qinghai-Tibet Plateau, and under the influence of climate warming, low-temperature frozen soil is gradually degrading into warm frozen soil. The ratio of ice to unfrozen water in warm frozen soil is highly sensitive to temperature changes, resulting in significant instability in its mechanical properties. To ensure the long-term stability of structures overlying permafrost foundations, conducting research on the mechanical characteristics of warm frozen soil and proposing effective measures to mitigate thaw settlement are crucial. This paper presents the research progress of our team in the field of warm frozen soil dynamics. Using a dynamic triaxial apparatus for frozen soil and a self-developed dynamic direct shear apparatus, we investigated the behavior of warm frozen soil under different temperatures, revealing the influence of temperature on its dynamic stress-strain relationship and dynamic parameters. The development of frozen soil creep theory is reviewed, and advancements in frozen soil dynamics research are summarized and discussed. This paper proposes the use of solar refrigeration technology to protect permafrost, introducing a solar-powered compression refrigeration device and its working principles. The active cooling performance of the device was tested through model experiments and field trials. Additionally, the design and construction techniques of all-season cooling embankments are discussed, providing theoretical and technical support for the stability control of subgrade engineering in permafrost regions. © 2025 The Author(s)

关键词： Active cooling technology Dynamics characteristic Transportation geotechnics Warm frozen soil

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Design and Wave Propagation Characterization of Starchiral Metamaterials

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Acta Mechanica Solida Sinica 2022年第2期35卷 215-227页

作者： Yajun Xin Han Wang Cong Wang Jinxin Yao Qian Ding Haoqiang Gao Shuliang Cheng Yongtao Sun Key Laboratory of Green Construction and Intelligent Maintenance for Civil Engineering of Hebei Province Yanshan UniversityQinhuangdao 060000China Hebei Province Low-Carbon and Clean Building Heating Technology Innovation Center Yanshan UniversityQinhuangdao 060000China Department of Mechanics and Tianjin Key Laboratory of Nonlinear Dynamics and Control Tianjin UniversityTianjin 300072China State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China

Metamaterials with simple artificial topological properties made from industrially produced single-phase materials have extraordinary innovation and *** this paper,we investigated wave propagation characteristics of a hexastarchiral lattice metamaterial with periodic assemblies and used the finite element(FE)method to study the band gap ***,in order to understand the mechanism of band gaps,we discussed the mode shapes of unit cells and found that the bending of the ligament and the overall rotation have a high correlation with the generation of omnidirectional band *** relationships bet ween geometric parameters and band gap properties have also been systematically studied,which demonstrated that the band gaps of the proposed metamaterial could be reasonably predicted through the evolution of geometric ***,the transmission characteristics of finite sandwich panel structures composed of periodic unit cells were calculated to verify the correctness of the band gap simulation results,which proved that the proposed artificial metastructure has potential application value in vibration and noise reduction projects.

关键词： Hexastarchiral lattice metamaterials Band gap properties Finite element method Rotational resonance

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Dynamic performance of six-axle locomotive subjected to asymmetric brake shoe forces

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Journal of Central South University 2020年第9期27卷 2776-2791页

作者： LIU Peng-fei ZHANG Kai-long CAO Yun-qiang State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang 050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang 050043China

To research the influence of asymmetric brake shoe forces(ABSF)induced by braking failure on the dynamic performance of six-axle locomotive,the static equilibrium model of three-axle bogie and dynamic model for locomotive are *** coupling vibration equations of axle hung motor and wheelset are *** the air braking,the influence mechanism of ABSF on the wheel-rail asymmetric motion and force characteristics are *** can be found that if the ABSF is applied in the front wheelset,all the wheelsets move laterally in the same *** the ABSF occurs in the middle or rear one,other wheelsets may move laterally towards the opposite *** motion amplitude and direction of all wheelsets strictly depend on the resultant moment of suspension yawing moment and brake shoe asymmetric *** the asymmetric braking,the free lateral gap of axle-box could increase the wheelset motion amplitude,but could not change the moving *** both the straight line and curve,the ABSF may lead to wheelset misaligning motion,intensify the wheel-rail lateral dynamic interaction and deteriorate wheel-rail contact *** for the steering wheelsets,the asymmetric braking increases the wheelset attack angle significantly,which forms the worst braking condition.

关键词： locomotive brake shoe force dynamic performance asymmetric braking wheel-rail contact

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Establishment of the thermo-mechanical coupling model of axle box bearings with track irregularity excitation and analysis of its temperature characteristics

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Applied Mathematics and Mechanics(English Edition) 2024年第11期45卷 1965-1986页

作者： Min WANG Shaopu YANG Yongqiang LIU Yanhong CHEN Kai ZHANG State Key Laboratory of Mechanical Behavior and System Safety of Traffic Engineering Structures Shijiazhuang Tiedao UniversityShijiazhuang050043China School of Traffic and Transportation Shijiazhuang Tiedao UniversityShijiazhuang050043China School of Mechanical Engineering Shijiazhuang Tiedao UniversityShijiazhuang050043China CRRC Tangshan Co. Ltd.Tangshan063000Hebei ProvinceChina China Water Resources Beifang Investigation Designand Research Co.Ltd.Tianjin300222China

As an important component of the running gear of high-speed trains,axle box bearings can cause lubricating grease failure and damage to bearing components under continuous high-temperature operation,which will affect the normal operation of highspeed ***,bearing temperature is one of the key parameters to be monitored in the online monitoring system for *** on the thermal network method,this paper establishes a thermal network model for the axle box bearing,considering the radial thermal deformation of the double-row tapered roller bearing components caused by the oil film characteristics and the temperature variations of the lubricating grease.A thermo-mechanical coupling model for the grease-lubricated double-row tapered roller axle box bearing of high-speed trains with track irregularity excitation is *** correctness of the model is verified using the test bench data,and the temperature of the bearing at different rotational speeds,loads,fault sizes,and ambient temperatures are investigated.

关键词： axle box bearing thermal network method temperature rotational speed

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