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CLASSIFICATION OF GEAR FAULTS USING HIGHER-ORDER STATISTICS AND SUPPORT VECTOR MACHINES

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Chinese Journal of mechanical engineering 2002年第3期15卷 243-247页

作者： Lai Wuxing Zhang Guicai Shi Tielin Yang Shuzischool of mechanical science and engineering, Huazhong university of science and technology,Wuhan 430074, china school of mechanical science and engineering Huazhong University of Science and Technology Wuhan 430074

Gears alternately mesh and detach in driving process, and then workingconditions of gears are alternately changing, so they are easy to be spalled and worn. But becauseof the effect of additive gaussian measurement noises, the signal-to-noises ratio is low; theirfault features are difficult to extract. This study aims to propose an approach of gear faultsclassification, using the cumulants and support vector machines. The cumulants can eliminate theadditive gaussian noises, boost the signal-to-noises ratio. Generalisation of support vectormachines as classifier, which is employed structural risk minimisation principle, is superior tothat of conventional neural networks, which is employed traditional empirical risk minimisationprinciple. Support vector machines as the classifier, and the third and fourth order cumulants asinput, gears faults are successfully recognized. The experimental results show that the method offault classification combining cumulants with support vector machines is very effective.

关键词： Support vector machine Gear Fault diagnosis Cumulant Featureextraction

Quasi-nano wear mechanism under repeated impact contact loading

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science china(Technological sciences) 2010年第6期53卷 1583-1589页

作者： ZHU JinHua1,REN XiangHong1,2,ZHANG JianJun1,3,XU YunHua1,3 & LU ZhengXin1,4 1 State Key Laboratory for mechanical Behavior of Materials,Xi’an Jiaotong university,Xi’an 710049,china 2 Xi’an Research Institute of High-tech,Xi’an 710025,china 3 school of Materials science and engineering,Xi’an university of Architecture and technology,Xi’an 710055,china 4 school of Materials science and engineering,Xi’an university of technology,Xi’an 710049,china State Key Laboratory for mechanical Behavior of Materials Xi’an Jiaotong University Xi’an China Xi’an Research Institute of High-tech Xi’an China school of Materials science and engineering Xi’an University of Architecture and Technology Xi’an China school of Materials science and engineering Xi’an University of Technology Xi’an China

A new quasi-nano wear mechanism (QNWM) has been proposed in this paper based on the facts of wear curve turning under high energy impact contact *** characteristic is that the wear rate of QNWM is only 1/10-1/3 that of delamination mechanism at the same energy *** diameters of wear debris and pits on the worn surfaces fall into the quasi-nanometer scale (about 50-120 nm).The necessary and sufficient conditions,which bring about the QNWM,are:(i) the nano-structure (nano-crystalline + amorphous phase) in impact contact surface layer has formed by the intensive impact strain;(ii) the delamination wear cracking in sub-surface layer must be restrained;(iii) the microcracks of QNWM are produced in amorphous phase of surface nano-structure layer rather than in nano-crystalline.

关键词： impact wear quasi-nano wear mechanism delamination wear mechanism nano-structure

Growth of HT-LiCoO2 thin films on Pt-metalized silicon substrates

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Rare Metals 2008年第3期27卷 266-272页

作者： ZHANG Yao~(a,b) CHUNG Chiyuen~b ZHU Min~a ~a school of mechanical engineering,South china university of technology,Guangzhou 510640,china ~b Department of Physics and Materials science,City university of Hong Kong,Hong Kong,china school of mechanical engineering South China University of Technology Guangzhou 510640 China Department of Physics and Materials science City University of Hong Kong Hong Kong China

Layered LiCoO2（HT-LiCoO2）films were grown on Pt-metalized silicon（PMS）substrates and polished bulk nickel（PBN）substrates by pulsed laser *** effects of substrate temperature,oxygen pressure,and substrate surface roughness on the microstructure of LiCoO2 films were *** has been found that a higher substrate temperature and a higher oxygen pressure favor the formation of better crystallized and less lithium-deficient HT-LiCoO2 *** HT-LiCoO2 film deposited on PBN substrates consists of large randomly orientated equiaxial grains,whereas on PMS substrate,it is made up of loosely packed highly[001]preferential orientated triangular shaped grains with the average grain size less than 100 *** measurements show that the highly[001]preferentially orientated nanostructured HT-LiCoO2 thin film grown on PMS substrate has good structural stability upon lithium insertion/extraction and can deliver an initial discharge capacity of approximately 45μA·h·cm-2·μm-1with a cycling efficiency of above 99% at the charge/discharge rate of 0.5 C.

关键词： thin film LiCoO2 pulsed laser deposition electrochemical properties thin film growth

Repetitious-Hot-Pressing Technique in Hot-Pressing Process

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Journal of Materials science & technology 2003年第5期19卷 486-488页

作者： Shixue SONG, Xing AI, Wei GAO and Jun ZHAO1)school of mechanical engineering, Shandong university, Jinan 250061, china2)school of science, Jinan university, Jinan 250022, china school of mechanical engineering Shandong University Jinan 250061 China school of science Jinan University Jinan 250022 China

A new pressing method was proposed for hot-pressing process. Experimental results indicated that the porosity in Al2O3/TiC/ Ni/Mo (hereafter called AI2O3/TiC composite) composite compacts decreases by 6% after adopting this new technique, compared to traditional hot-pressing technique under the same sintering temperature. The flexural strength and Vicker hardness increase from 883 MPa to 980 MPa and from 16 GPa to 21.1 GPa, respectively. A theoretical model was given to analyze the densification mechanism of the composite in the process of repetitious-hot-pressing.

关键词： Hot-pressing sintering Repetitious-hot-pressing sintering Composite

Two-Sublattice Thermodynamic Model on Carbonitride Precipitation in Microalloyed Steels Bearing Nb-V-Ti

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Journal of Iron and Steel Research International 2011年第S1期18卷 271-277页

作者： XIANG Song 1,3,LIU Guo-quan 2 (1.school of Materials and Metallurgy,Guizhou university,Guiyang 550003,Guizhou,china 2.school of Materials science and engineering,university of science and technology,Beijing,Beijing 100083,china 3.The Key Laboratory for mechanical Behavior and Microstructure of Materials,Guizhou Province,Guiyang 550003,Guizhou,china) Guizhou Univ Sch Met & Mat Guiyang 550003 Guizhou Peoples R China Key Lab Mech Behav & Microstruct Mat Guiyang 550003 Guizhou Peoples R China Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

Based on the two sublattice model of the regular solution,one being metal atom sublattice and another being interstitial atom sublattice,a thermodynamic model for the precipitates of niobium carbonitride,vanadium carbonitride and titanium carbonitride was established to study the starting-temperature of precipitates and the austenite compositions at given temperature in a low carbon *** calculation results show that starting-temperature of the precipitation of niobium carbonitride,vanadium carbonitride and titanium carbonitride are 1100℃,920℃ and 1340℃,respectively,the mole fraction of carbonitride precipitates is 8.65×10-4 in the 0.053C-0.0028N-1.28Mn-0.008S-0.031Al-0.046Nb-0.008Ti0.029V-Fe *** the N content is from 0.0028% to 0.0056%,the starting-temperature of the precipitation of the titanium carbonitride changes from 1340℃ to 1430℃.And the C content is from 0.053% to 0.07%,the startingtemperature of the precipitation of the titanium carbonitride hardly changes,but the atomic fraction of niobium in the carbonitride obviously increases.

关键词： microalloyed steel carbonitride precipitation two sublattice model thermodynamics

A Special TMCP Used to Develop a 800MPa Grade HSLA Steel

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Journal of university of science and technology Beijing 2001年第3期8卷 224-228页

作者： Chengjia Shang,Xuemin Wang, Xinlai He, Shanwu Yang, Yi Yuan Material science and engineering school, university of science and technology Beijing, Beijing, 100083, china Material science and Eng. school Univ. of Sci. and Technol. Beijing Beijing 100083 China

The effect of relaxation after finished rolling on structures and properties of four microalloyed steel with different content of Nb and Ti was investigated. By alloy designing and control rolling + relaxation-precipitation-control phase trail storm ati on (RPC) process, a new 800 MPa grade HSLA plate steel could be obtained, the microstructure is composite ultra-fine lath bainite/martensite. The tempering process and mechanical properties of this kind of HSLA steel were investigated. The yield strength can achieve 800 MPa, and the ductility and impact toughness is satisfied.

关键词： HSLA steel microstructure and mechanical properties TMCP (thermomechanical control process) RPC

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

Electrical Breakdown Characteristic of Nanostructured W-Cu Contacts Materials

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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

Study of Laser Lap Welding of SUS301L Austenitic Stainless Steel Using Optimal Design Method

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稀有金属材料与工程 2011年第S4期40卷 63-67页

作者： Liu Jia,Shi Yan,Zhang Hong school of Electromechanical engineering,Changchun university of science and technology,Changchun 130022,china Changchun Univ Sci & Technol Sch Electromech Engn Changchun 130022 Peoples R China

This paper presents an experimental design approach to process parameter optimization for the laser lap welding of SUS301L austenitic stainless steels using Nd:YAG laser in order to reduce the welding deformations of the back of the welding seams while ensuring mechanical properties of welding *** determine the optimal laser-welding parameters,a set of mathematical models were developed relating welding parameters to each of the weld *** were validated both statistically and *** order to reduce experimental error and the number of specimens,the part of orthogonal experiments were used in this *** quality criteria set for the weld to determine optimal parameters were the maximization of weld width and the minimization of weld *** power,welding speed,the laser irradiation angle,the focused distance and shield gas of 3.5kW,7.0m/min,70°,0mm and N2 with the flow of 30L/min,respectively,with a fiber diameter of 600μm were identified as the optimal set of process parameters.

关键词： laser lap welding sus301l austenitic stainless steel welding deformation orthogonal experiments