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Friction 2024年第1期12卷 74-94页

作者： Jiabao YIN Chun LU Jiliang MO School of Mechanical engineering Southwest Jiaotong UniversityChengdu 610031China Technology and equipment of Rail Transit Operation and maintenance Key laboratory of Sichuan Province Chengdu 610031China

A comprehensive modeling strategy for studying the thermomechanical tribological behaviors is proposed in this *** wear degradation considering the influence of temperature(T)is predicted by Archard wear model with the help of the UMESHMOTION subroutine and arbitrary Lagrangian–Eulerian(ALE)remeshing *** the proposed method,the thermomechanical tribological behaviors of railway vehicle disc brake system composed of forged steel brake disc and Cu-based powder metallurgy(PM)friction block are studied *** effectiveness of the proposed methodology is validated by experimental test on a self-designed scaled brake test bench from the perspectives of interface temperature,wear degradation,friction noise and vibration,and contact status *** work can provide an effective way for the investigation of thermomechanical tribological behaviors in the engineering field.

关键词： tribological behaviors thermomechanical field wear prediction finite element simulation disc brake system railway vehicle

A High-Accuracy Curve Boundary Recognition Method Based on the Lattice Boltzmann Method and Immersed Moving Boundary Method

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Computer Modeling in engineering & Sciences 2024年第9期140卷 2533-2557页

作者： Jie-Di Weng Yong-Zheng Jiang Long-Chao Chen Xu Zhang Guan-Yong Zhang Hunan Provincial Key laboratory of Health maintenance for Mechanical equipment Hunan University of Science and TechnologyXiangtan411201China School of Mechanical engineering Hunan Chemical Vocational Technology CollegeZhuzhou412000China

Applying numerical simulation technology to investigate fluid-solid interaction involving complex curved bound-aries is vital in aircraft design,ocean,and construction ***,current methods such as Lattice Boltzmann(LBM)and the immersion boundary method based on solid ratio(IMB)have limitations in identifying custom curved ***,IBM based on velocity correction(IBM-VC)suffers from inaccuracies and numerical ***,this study introduces a high-accuracy curve boundary recognition method(IMB-CB),which identifies boundary nodes by moving the search box,and corrects the weighting function in LBM by calculating the solid ratio of the boundary nodes,achieving accurate recognition of custom curve *** addition,curve boundary image and dot methods are utilized to verify *** findings revealed that IMB-CB can accurately identify the boundary,showing an error of less than 1.8%with 500 ***,the flow in the custom curve boundary and aerodynamic characteristics of the NACA0012 airfoil are calculated and compared to *** showed that IMB-CB yields lower lift and drag coefficient errors than IBM-VC,with a 1.45%drag coefficient *** addition,the characteristic curve of IMB-CB is very stable,whereas that of IBM-VC is *** the moving boundary problem,LBM-IMB-CB with discrete element method(DEM)is capable of accurately simulating the physical phenomena of multi-moving particle flow in complex curved *** research proposes a new curve boundary recognition method,which can significantly promote the stability and accuracy of fluid-solid interaction simulations and thus has huge applications in engineering.

关键词： Fluid-solid interaction curve boundary recognition method Lattice Boltzmann method immersed moving boundary method

Toughened (Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composites fabricated by one-step reactive sintering with a unique SiB_(6) additive

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Journal of Advanced Ceramics 2024年第1期13卷 86-100页

作者： Wei Hao Xinzhe Lu Ling Li Tao Wang Guoliang Ren Huangyue Cai Xiaofeng Zhao Dongyun Wang Na Ni Zhejiang Provincial Key laboratory of Urban Rail Transit Intelligent Operation and maintenance Technology&equipment Zhejiang Normal UniversityZhejiang 321004China Key Lab of Education Ministry for Power Machinery and engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Materials Science and engineering Shanghai Jiao Tong UniversityShanghai 200240China

High-entropy diboride has been arousing considerable interest in recent ***,the low toughness and damage tolerance limit its applications as ultra-high-temperature structural *** we report that a unique SiB_(6) additive has been first incorporated as boron and silicon sources to fabricate a high-entropy boride(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–SiC composite though one-step boro/carbothermal reduction reactive sintering.A synergetic effect of high-entropy sluggish diffusion and SiC secondary phase retarded the grain growth of the(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))B_(2)–51SiC *** small grain size was beneficial to shorten the diffusion path for mass transport,thereby enhancing the relative density to~99.3%.These results in an increase of fracture toughness from~5.2 in HEBS-1900 to~7.7 MPa·m^(1/2) in HEBS-2000,which corresponded to a large improvement of 48%.The improvement was attributed to a mixed mode of intergranular and transgranular cracking for offering effective pinning in crack propagation,resulting from balanced grain boundary strength collectively affected by improved densification,solid solution strengthening,and incorporation of SiC secondary phase.

关键词： high-entropy diboride silicon hexaboride boro/carbothermal reduction reactive sintering fracture toughness

Study on cumulative effects of biological craniocerebral trauma under repeated blast

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Theoretical & Applied Mechanics Letters 2024年第3期14卷 174-183页

作者： Xingyuan Huang Bingchen Xia Lijun Chang Zhikang Liao Hui Zhao Zhihua Cai Hunan Provincial Key laboratory of Health maintenance for Mechanical equipment Hunan University of Science and TechnologyXiangtan 411201China School of Mechanical and Electrical engineering Foshan UniversityFoshan 528231China Institute for Traffic Medicine PLA Army Characteristic Medical CenterChongqing 400042China

Repeated blast impacts on personnel in explosive environments can exacerbate craniocerebral *** existing studies focus on the injury effects of a single blast,lacking in-depth analysis on the injury effects and cumulative effects of repeated ***,rats were used as the experimental samples to suffer from explosion blasts with different peak air overpressures(167 kPa~482 kPa)and varying number of repeated *** cumulative effect of craniocerebral trauma was most pronounced for moderate repeated blast,showing approximately 95%increase of trauma severity with penta blast,and an approximately 85%increase of trauma severity with penta minor *** cumulative effect of craniocerebral trauma from severe,repeated blast has a smaller rate of change compared to the other two *** severity of trauma from penta blast increased by approximately 69%compared to a single *** physiological,pathological and biochemical analysis show that the degree of neurological trauma caused by repeated blasts is higher than that of single blasts,and the pathological trauma to brain tissue is more extensive and *** trauma degree remains unchanged after double blast,increases by one grade after triple or quadruple blast,and increases by two grades after penta blast.

关键词： Repeated blast Craniocerebral trauma Trauma severity grade Cumulative effects

Analysis of strength characteristics of loess before and after freezing using a hollow cylinder torsional shear apparatus

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Research in Cold and Arid Regions 2024年第2期16卷 63-72页

作者： Peng Shen QingZhi Wang JianHong Fang ChenWei Wang Kui Zhang School of Civil engineering and Water Resources Qinghai UniversityXiningQinghai 810016China Qinghai Scientific Research Observation Base Key Laboratory of Highway Construction and Maintenance Technology in Permafrost RegionsMinistry of TransportXiningQinghai 810016China

This paper aims to comprehensively analyze the influence of the principal stress angle rotation and intermediate principal stress on loess's strength and deformation characteristics. A hollow cylinder torsional shear apparatus was utilized to conduct tests on remolded samples under both normal and frozen conditions to investigate the mechanical properties and deformation behavior of loess under complex stress conditions. The results indicate significant differences in the internal changes of soil particles, unfrozen water, and relative positions in soil samples under normal and frozen conditions, leading to noticeable variations in strength and strain *** frozen state, loess experiences primarily compressive failure with a slow growth of cracks, while at normal temperature, it predominantly exhibits shear failure. With the increase in the principal stress angle, the deformation patterns of the soil samples under different conditions become essentially consistent, gradually transitioning from compression to extension, accompanied by a reduction in axial strength. The gradual increase in the principal stress axis angle(α) reduces the strength of the generalized shear stress and shear strain *** an increasing α, frozen soil exhibits strain-hardening characteristics, with the maximum shear strength occurring at α = 45°. The intermediate principal stress coefficient(b) also significantly impacts the strength of frozen soil, with an increasing b resulting in a gradual decrease in generalized shear stress strength. This study provides a reference for comprehensively exploring the mechanical properties of soil under traffic load and a reliable theoretical basis for the design and maintenance of roadbeds.

关键词： Loess Hollow cylinder torsional shear apparatus Major principal stress angle Intermediate principal stress coefficient

Development of Mixed Insulation Oil as Alternative Liquid Dielectric:A Review

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CSEE Journal of Power and Energy Systems 2024年第3期10卷 1242-1258页

作者： Jian Hao Jingwen Zhang Wenyu Ye Ruijing Liao Lijun Yang State Key laboratory of Power Transmission equipment Technology School of Electrical EngineeringChongqing UniversityChongqing 400044China IEEE CSEE

Use of traditional mineral oil(MO)as a liquid insulation in transformers has spanned more than 130 ***,MO has poor heat resistance,a low ignition point,and is a non-renewable resource,which does not meet development requirements for high-performance and environmentally friendly insulation ***,researchers have explored alternatives such as natural ester(NE)and synthetic ester(SE)oils,as well as mixed insulation *** insulating oil is a blend of diverse insulating oil types,with optimal performance achieved by adjusting proportions of base *** article summarizes the innovative achievements and development of mixed insulation oil in terms of development of mixed ratio,basic physical chemical properties,electrical properties,thermal stability,and application including operation and maintenance *** these efforts,this article aims to provide recommendations for future development of mixed insulating oils to advance liquid dielectric research based on enhancement mechanisms.

关键词： Environmentally friendly insulation oil ester oils high-performance mineral oil mixed insulation oils

Shear mechanical properties and frictional sliding responses of rough joint surfaces under dynamic normal displacement conditions

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Journal of Central South University 2024年第7期31卷 2393-2410页

作者： ZHU Qiang YIN Qian TAO Zhi-gang HE Man-chao ZHENG Bo-wen JING Hong-wen REN Shu-lin ZHANG Qiang MENG Bo BAI Dong-feng WU Sai-sai WU Jiang-yu State Key laboratory of Intelligent Construction and Healthy Operation and maintenance of Deep Underground engineering Xuzhou 221116China State Key laboratory for Geomechanics&Deep Underground engineering China University of Mining and Technology(Beijing)Beijing 100083China Key laboratory of Shale Gas and Geoengineering Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China CCCC First highway Survey and Design Research Institute Co. Ltd.Xi’an 710075China

A comprehensive understanding of the dynamic frictional characteristics in rock joints under high normal load and strong confinement is essential for ensuring the safety of deep engineering construction and mitigating geological *** study conducted shear experiments on rough rock joints under displacement-controlled dynamic normal loads,investigating the shear behaviors of joints across varying initial normal loads,normal loading frequencies,and normal loading *** results showed that the peak/valley shear force values increased with initial normal loads and normal loading frequencies but showed an initial increase followed by a decrease with normal loading *** normal loading can either increase or decrease shear strength,while this study demonstrates that higher frequencies lead to enhanced *** initial normal loading and normal loading frequency result in a gradual decrease in joint roughness coefficient(JRC)values of joint surfaces after *** correlations existed between frictional energy dissipation and peak shear forces,while post-shear joint surface roughness exhibited a negative correlation with peak shear forces through linear regression *** study contributes to a better understanding of the sliding responses and shear mechanical characteristics of rock joints under dynamic disturbances.

关键词： dynamic normal displacement shear strength variations phase lag phenomenon stick-slip

High-performance wearable bimetallic nanowire-assisted composite foams for efficient electromagnetic interference shielding,infrared stealth,and piezoresistive sensing

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Nano Research 2024年第7期17卷 6757-6765页

作者： Tianyi Hang Lijie Zhou Chenhui Xu Yiming Chen Jiahui Shen Jiajia Zheng Pingan Yang Xiping Li Heng Luo Guoxiu Tong Key laboratory of Urban Rail Transit Intelligent Operation and maintenance Technology and equipment of Zhejiang Province College of EngineeringZhejiang Normal UniversityJinhua 321004China School of Automation Chongqing University of Posts and TelecommunicationsChongqing 400065China State Key laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Key laboratory of the Ministry of Education for Advanced Catalysis Materials College of Chemistry and Materials ScienceZhejiang Normal UniversityJinhua 321004China

With the accelerated development of modern detection and communication technology,the multifunctional wearable materials with excellent electromagnetic interference(EMI)shielding,infrared stealth,and human monitoring for improving military combat capability have received extensive *** this work,the lightweight melamine foam(MF)@silver nanowires(AgNWs)-iron nanowires(FeNWs)(AgFe-MF)was fabricated by a vacuum-assisted dip-coating *** to the porous structure and synergistic electrical and magnetic losses,this lightweight(0.115 g/cm^(3))composite foam with an ultra-low filler content(0.62 vol.%)exhibited an ideal EMI shielding efficiency of 38.4 *** the other hand,the AgFe-MF realized a powerful multifunctional *** surface saturation temperature of the AgFe-MF reached 94.2℃under a low applied voltage of 1.8 V and remained extremely fast heating and cooling response and terrific working stability,resulting in excellent infrared stealth and camouflage ***,taking virtues of the elastic porous conductive architecture,the AgFe-MF was utilized as a piezoresistive sensor exhibiting board compressive interval of 0–1.62 kPa(50%strain)with a good sensitivity of 0.57 kPa^(−1).This work will provide new ideas and insights for developing multifunctional wearable devices in the fields of EMI shielding,thermal management,and piezoresistive sensing.

关键词： metal nanowires porous foams electromagnetic interference shielding infrared stealth wearable sensors

Label Recovery and Trajectory Designable Network for Transfer Fault Diagnosis of Machines With Incorrect Annotation

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IEEE/CAA Journal of Automatica Sinica 2024年第4期11卷 932-945页

作者： Bin Yang Yaguo Lei Xiang Li Naipeng Li Asoke K.Nandi the Key laboratory of Education Ministry for Modern Design and Rotor-Bearing System the School of Mechanical EngineeringXi’an Jiaotong UniveristyXi’an 710049 the Hunan Provincial Key Labortory of Health maintenance for Mechanical equipment Hunan Univeristy of Science and TechnologyXiangtan 411201China the Key laboratory of Education Ministry for Modern Design and Rotor-Bearing System Xi’an Jiaotong UniveristyXi’an 710049China the Department of Electronic and Electrical engineering Brunel University LondonUxbridge UB83PHUK

The success of deep transfer learning in fault diagnosis is attributed to the collection of high-quality labeled data from the source ***,in engineering scenarios,achieving such high-quality label annotation is difficult and *** incorrect label annotation produces two negative effects:1)the complex decision boundary of diagnosis models lowers the generalization performance on the target domain,and2)the distribution of target domain samples becomes misaligned with the false-labeled *** overcome these negative effects,this article proposes a solution called the label recovery and trajectory designable network(LRTDN).LRTDN consists of three ***,a residual network with dual classifiers is to learn features from cross-domain ***,an annotation check module is constructed to generate a label anomaly indicator that could modify the abnormal labels of false-labeled samples in the source *** the training of relabeled samples,the complexity of diagnosis model is reduced via semi-supervised ***,the adaptation trajectories are designed for sample distributions across *** ensures that the target domain samples are only adapted with the pure-labeled *** LRTDN is verified by two case studies,in which the diagnosis knowledge of bearings is transferred across different working conditions as well as different yet related *** results show that LRTDN offers a high diagnosis accuracy even in the presence of incorrect annotation.

关键词： Deep transfer learning domain adaptation incorrect label annotation intelligent fault diagnosis rotating machines

Case study on the mechanics of NPR anchor cable compensation for large deformation tunnel in soft rock in the Transverse Mountain area,China

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Journal of Central South University 2024年第6期31卷 2054-2069页

作者： LI Yong ZHENG Jing HUO Shu-sen WANG Feng-nian HE Man-chao TAO Zhi-gang College of Geoscience and Surveying engineering China University of Mining and Technology(Beijing)Beijing 100083China State Key Labortaory for Fine Exploration and Intelligent Development of Coal Resources China University of Mining and Technology(Beijing)Beijing 100083China State Key laboratory for Tunnel engineering China University of Mining and Technology(Beijing)Beijing 100083China Shanxi Provincial Transportation Technology Research and Development Co.Ltd. Key Laboratory of Highway Construction and Maintenance Technology in Loess AreaTransportation IndustryTaiyuan 030000China

A study was conducted to analyze the deformation mechanism of strongly weathered quartz schist in the Daliangshan Tunnel,located in the western Transverse Mountain area.A large deformation problem was experienced during the tunnel *** mitigate this problem,a support system was designed incorporating negative Poisson ratio(NPR)anchor cables with negative Poisson ratio *** model experiments,field experiments,and numerical simulation experiments were conducted to investigate the compensation mechanical behavior of NPR anchor *** large deformations of soft rocks in the Daliangshan Tunnel are caused by a high ground stress,a high degree of joint fracture development,and a high degree of surrounding rock fragmentation.A compensation mechanics support system combining long and short NPR anchor cables was suggested to provide sufficient counter-support force(approximately 350 kN)for the surrounding rock inside the *** the NPR anchor cable support system with the original support system used in the Daliangshan tunnel showed that an NPR anchor cable support system,combining cables of 6.3 m and 10.3 m in length,effectively prevented convergence of surrounding rock deformation,and the integrated settlement convergence value remained below 300 *** study provides an effective scientific basis for resolving large deformation problems in deeply buried soft rocks in western transverse mountain areas.

关键词： soft rock large deformation NPR anchor cable physical model numerical simulation compensation mechanics