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Study on Contact Fatigue Life and Failure Mechanism of Subquenched 42CrMo Steel

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材料热处理学报 2004年第5期25卷 260-262页

作者： HEBo-lin YUYing-xia SHAOEr-yu schoolofmechanical＆electricalengineering EastChinaJiaotongUniversityNanchangChina MaterialInstitute HenanUniversityofScienceandTechnologyLuoyangChina

The effect of undissolved ferrite amount in subcritically quenched 42CrMo steel on contact fatigue properties and failure mechanism were studied. The amount of undissolved ferrite in the steel were 0%,3%,10%,15% and 20% in volume fraction, respectively. The experimental results show that the existence of undissolved ferrite can increase the contact fatigue life The contact fatigue life can be prolonged with increasing the amounts of undissolved ferrite The grain size can be fined by using subcritical quenching process and the area of phase boundaries can also be greatly increased. The stress relaxation and grain refinement due to occurring of plastic deformation are main reasons for improving the fatigue life. The existence of undissolved ferrite can increase the crack initiation period. Under the experiment conditions, when the amount of undissolved ferrite is 10%, the longest contact fatigue life can be the obtained.

关键词：亚临界灭弧接触疲劳失效机理铁素体 42CrMo钢

electrical breakdown characteristic of a Ce-doped W-Cu contact material

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Rare Metals 2010年第3期29卷 261-264页

作者： HU Kewen,CHEN Mianzhi,and YE Heng school of Materials Science and engineering,Xi’an university of technology,Xi’an 710048,china school of Materials Science and engineering Xi’an University of Technology Xi’an China

W-Cu composite powder doped with Ce （1.5 wt.%） was prepared by mechanical alloying （MA）,and the W-Cu contact material was fabricated by hot pressing sintering in an electrical vacuum *** microstructure,electric conductivity,hardness,and breakdown voltage of the Ce-doped W-Cu alloy were measured and compared with a conventional W-Cu alloy prepared by powder *** results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of the Ce-doped W-Cu contact ***,the Ce-doped W-Cu contact material shows the characteristic of spreading electric arc,which is beneficial to electric arc erosion.

关键词： doping rare earth W-Cu alloy electrical breakdown

Theoretical analysis and experiment of micromechanics and mechanics-optics coupling of distributed optic-fiber crack sensing

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中国科学：技术科学英文版 2011年第S1期54卷 185-191页

作者： LIU HaoWu 1,2,CHEN Jiang 2,SUN Man 3 & DING Rui 2 1 State Key Laboratory of Hydraulics and Mountain River engineering,Sichuan university,Chengdu 610065,china 2 school of Water Resource Hydropower,Sichuan university,Chengdu 610065,china 3 school electrical engineering and Information,Sichuan university,Chengdu 610065,china Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Peoples R China Sichuan Univ Sch Water Resource Hydropower Chengdu 610065 Peoples R China Sichuan Univ Sch Elect Engn & Informat Chengdu 610065 Peoples R China

The micromechanical behaviors and mechanics-optics coupling effects of optic-fiber-concrete complex in the distributed optic-fiber sensing concrete-crack technology,which was used in health monitoring of Wu Gorge Bridge on Yangtze River and a large dam successfully,have been investigated.A micromechanical theoretical analysis method and micromechanical frictional contact bi-interface model,as well as a modified optical theoretical analysis method of the mechanics-optics coupling effects are presented.A series of verification experiments,including mechanical experiments and mechanics-optics coupling experiments,have been *** results of micromechanical theoretical analysis and the analysis of the modified theory of mechanics-optics coupling along with mechanical and optical experimental data are shown to be in close *** the micromechanical theory and the modified theory of mechanics-optics coupling with their analysis methods can not only enhance credibility of this novel distributed sensing technology but also provide a way to understand its sensing mechanism and optimize its technical details and system.

关键词： optic-fiber sensing mechanics-optics coupling micromechanics health monitoring concrete structure crack detection

Tribological Properties Prediction of Brake Lining for Automobiles Based on BP Neural Network

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Tribological Properties Prediction of Brake Lining for Autom...

electrical Breakdown Characteristic of Nanostructured W-Cu Contacts Materials

2010 Chinese Control and Decision Conference

作者： Yan Yin~1,Jiusheng Bao~1,Lei Yang~2 1.school of mechanical and electrical engineering,china university of mining and technology,xuzhou,221116 2.Xuhai College,china university of mining and technology,xuzhou,221008

＜正＞By many tribological experiments of brake lining for automobiles,the original experimental data were firstly obtained,which contains the influencing rules of braking conditions on tribological *** on the artificial neural network technology and the experimental data specimens,the BP neural network model was established to predict the tribological *** parameters of braking conditions（braking pressure,sliding velocity and surface temperature） were selected as input vectors,and two parameters of tribological performance（friction coefficient and wear rate） were selected as output *** contrast of prediction values and experimental results,it is found that the neural network can predict properly the influencing rules of braking conditions on tribological *** is more,the neural network has quite favorable ability for predicting of friction *** it has bad ability for predicting of wear rate,especially when the pressure,velocity and temperature are *** a whole,this paper has proved that it is feasible and valuable to use neural network for predicting tribological properties of friction materials.

关键词： neural network friction coefficient wear rate prediction brake lining

来源： cnki会议评论

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Journal of Wuhan university of technology(Materials Science) 2006年第4期21卷 32-35页

作者：王俊勃 school of mechanical and electrical engineering Xi'an Polytechnic UniversityXi'an 710048 ChinaSchool of Science Xi'an Jiaotong University Xi'an 710049China

Nanostructured （ NS ）W-Cu composite powder was prepared by mechanical alloying （ MA ）, and nanostructared bulk of W-Cu contact material was fabricated by hot press sintering in an electrical vacuum furnace. The rnicrostructure, electric conductivity, hardness and break down voltage of NS W- Cu alloys were measured and compared to those of conventional W-Cu alloys prepared by powder metallurg＇y. The experimental results show that microstructural refinement and uniformity can improve the breakdown behavior and the electric arc stability of nanostructared W- Cu contacts materials. Also, the wanostructured W- Cu contact material shows the characteristic of spreading electric arcs, which is of benefit to electric arc erosion.

关键词： nanostructured materials W-Cu alloy electrical breakdown

Conductive and stable polyphenylene/CNT composite membrane for electrically enhanced membrane fouling mitigation

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Frontiers of Environmental Science & engineering 2024年第1期18卷 35-47页

作者： Huijuan xie Haiguang Zhang Xu Wang Gaoliang Wei Shuo Chen xie Quan Key Laboratory of Industrial Ecology and Environmental engineering(Ministry of Education) School of Environmental Science and TechnologyDalian University of TechnologyDalian 116024China

Nanocarbon-based conductive membranes, especially carbon nanotube (CNT)-based membranes, have tremendous potential for wastewater treatment and water purification because of their excellent water permeability and selectivity, as well as their electrochemically enhanced performance (e.g., improved antifouling ability). However, it remains challenging to prepare CNT membranes with high structural stability and high electrical conductivity. In this study, a highly electroconductive and structurally stable polyphenylene/CNT (PP/CNT) composite membrane was prepared by electropolymerizing biphenyl on a CNT hollow fiber membrane. The PP/CNT membrane showed 3.4 and 5.0 times higher electrical conductivity than pure CNT and poly(vinyl alcohol)/CNT (PVA/CNT) membranes, respectively. The structural stability of the membrane was superior to that of the pure CNT membrane and comparable to that of the PVA/CNT membrane. The membrane fouling was significantly alleviated under an electrical assistance of −2.0 V, with a flux loss of only 11.7% after 5 h filtration of humic acid, which is significantly lower than those of PP/CNT membranes without electro-assistance (56.8%) and commercial polyvinylidene fluoride (PVDF) membranes (64.1%). Additionally, the rejection of negatively charged pollutants (humic acid and sodium alginate) was improved by the enhanced electrostatic repulsion. After four consecutive filtration-cleaning cycle tests, the flux recovery rate after backwashing reached 97.2%, which was much higher than those of electricity-free PP/CNT membranes (67.0%) and commercial PVDF membranes (61.1%). This study offers insights into the preparation of stable conductive membranes for membrane fouling control in potential water treatment applications.

关键词： Polyphenylene CNTs Membrane Electro-assistance Membrane fouling mitigation

Microstructures of Sintered Mo-Cu Alloys with mechanically Activated Powder

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Rare Metals 2001年第2期20卷 112-116页

作者： Chengchang Jia, Zhong He, Xuekuan Su, Ziqin Yang, Jun Zhao, Zizhang xie (school of Materials Science and engineering, university of Science and technology Beijing, Beijing 100083, china Beliing Polytechnic university, Beijing 100022, Beijing) Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Beijing Polytech Univ Beijing 100022 Peoples R China

mechanical activation and liquid phase sintering were used to manufacture high performance Mo-Cu alloy and develop new processes. The microstructures and properties of the alloy were investigated. The experimental results showed that: (1) the ball milled Mo/Cu powder has lamellar structure, (2) the microstructures of the sintered Mo-Cu alloy were homogenous compound structures of adhesive phase Cu linking Mo grains, (3) Mo grains frequently strung or gathered in Cu phase, and (4) the full densities of Mo-Cu alloy was achieved through sintering and special densification process. As a result, the properties of the alloy are good enough to satisfy various requirements.

关键词： Mo-Cu alloy powder metallurgy mechanical activation microstructure

Game-theoretic multi-agent motion planning in a mixed environment

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Control Theory and technology 2024年第3期22卷 379-393页

作者： Xiaoxue Zhang Lihua xie school of electrical and Electronic engineering Nanyang Technological UniversitySingapore City 639798Singapore

The motion planning problem for multi-agent systems becomes particularly challenging when humans or human-controlled robots are present in a mixed *** address this challenge,this paper presents an interaction-aware motion planning approach based on game theory in a receding-horizon manner Leveraging the framework provided by dynamic potential games for handling the interactions among agents,this approach formulates the multi-agent motion planning problem as a differential potential game,highlighting the effectiveness of constrained potential games in facilitating interactive motion planning among ***,online learning techniques are incorporated to dynamically learn the unknown preferences and models of humans or human-controlled robots through the analysis of observed *** evaluate the effectiveness of the proposed approach,numerical simulations are conducted,demonstrating its capability to generate interactive trajectories for all agents,including humans and human-controlled agents,operating within the mixed *** simulation results illustrate the effectiveness of the proposed approach in handling the complexities of multi-agent motion planning in real-world scenarios.

关键词： Motion planning Differential potential game Multi-agent systems Constrained potential game

Preparation and Property of Chromium Carbide Thermal Diffusion Coating on Cold Working Die Materials

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Journal of Wuhan university of technology(Materials Science) 2010年第4期25卷 596-599页

作者：袁志华 school of electrical and mechanical engineering North University of China school of Equipment engineering Shenyang Ligong University

Thermal diffusion （TD） salt bath chromizing of cold working dies was studied. Firstly, it obtained an ideal salt bath formula by comparing with a variety of formulas, and then obtained the influence rule of coating thickness based on studying of some process parameters. The microstructure morphologies and phase structures of the TD chromizing coating were investigated by X-ray diffraction （XRD）, energy-dispersive spectrometry （EDS） and other modern analysis methods. Meanwhile, it carried out a system of testing and analysis of coating, such as hardness, wear resistance, etc.

关键词： chromium carbide coating thermal diffusion process cold working die preparation SEM EDS