期刊文献+
共找到56篇文章
< 1 2 3 >
每页显示 20 50 100
Surface Roughness and Roundness of Bearing Raceway Machined by Floating Abrasive Polishing and Their Effects on Bearing's Running Noise 被引量:3
1
作者 PANG Guibing QI Xuezhi +4 位作者 MA Qinyi ZHAO Xiujun WEN Chunsheng XU Wenji PENG Yanping 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第3期543-550,共8页
As the two most important indexes of bearing raceway, surface roughness and roundness have significant influence on bearing noise. Some researchers have carried out studies in this field, however, reason and extent of... As the two most important indexes of bearing raceway, surface roughness and roundness have significant influence on bearing noise. Some researchers have carried out studies in this field, however, reason and extent of the influence of raceway surface geometric characteristics on bearing running noise are not perfectly clear up to now. In this paper, the raceway of 6309 type bearing's inner and outer ring is machined by floating abrasive polishing adopting soft abrasive pad. Surface roughness parameters, arithmetical mean deviation of the profile Ra, the point height of irregularities Rz, maximum height of the profile Rmax and roundness fof raceways, are measured before and after machining, and the change rules of the measured results are studied. The study results show that the floating abrasive polishing can reduce the surface geometric errors of bearing raceway evidently. The roundness error is reduced by 25%, Rm^x value is reduced by 35.5%, Rz value is reduced by 22% and Ra value is reduced by 5%. By analyzing the change of the geometrical parameters and the shape difference of the raceway before and after machining, it is found that the floating abrasive polishing method can affect the roundness error mainly by modifying the local deviation of the raceway's surface profile. Bearings with different raceway surface geometrical parameter value are assembled and the running noise is tested. The test results show that Ra has a little, Rmax and Rz have a measurable, and the roundness error has a significant influence on the running noise. From the viewpoint of controlling bearings' running noise, raceway roundness error should be strictly controlled, and for the surface roughness parameters, R,n^x and Rz should be mainly controlled. This paper proposes an effective method to obtain the low noise bearing by machining the raceway with floating abrasive polishing after super finishing. 展开更多
关键词 surface roughness roundness POLISHING LAPPING bearing raceway noise
下载PDF
Mechanical behaviors of cross roller bearings with raceway roundness error 被引量:3
2
作者 HUANG Jian LI Chao-yang CHEN Bing-kui 《Journal of Central South University》 SCIE EI CAS CSCD 2021年第7期2091-2104,共14页
Taking the raceway roundness error into account,mechanical characteristics of cross roller bearings(CRBs)were investigated.A static analysis model of CRBs considering the raceway roundness error was established.Based ... Taking the raceway roundness error into account,mechanical characteristics of cross roller bearings(CRBs)were investigated.A static analysis model of CRBs considering the raceway roundness error was established.Based on this model,the rotational accuracy and load distribution of CRBs under constraints of geometry and external loads were derived.The fatigue life of CRBs with roundness error was calculated by applying Palmgren-Miner linear cumulative damage theory.The influence of inner and outer raceway roundness error on the performance of the CRBs,such as rotational accuracy,load distribution,and fatigue life,was studied through the analysis of examples.The results indicate that the influence of roundness error on the rotating inner raceway is more significant than that of roundness error on the nonrotating outer raceway.The roundness error on the rotating inner raceway always degrades the performance of CRBs.However,a proper roundness error on the nonrotating outer raceway can reduce the loads acting on the rollers and thus improve the fatigue life of CRBs.The effect of the roundness error amplitude on the bearing performance is ordinal,whereas the effect of the roundness order on the bearing performance is not in order. 展开更多
关键词 cross roller bearings roundness error load distribution rotational accuracy fatigue life
下载PDF
Vision testing method for diameter,roundness and hardness of table tennis ball 被引量:2
3
作者 QIU Zu-rong LU Yao-huan +2 位作者 XUE Jie PANG Jiang-miao LI Hao-peng 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2019年第1期1-8,共8页
Under the premise of fully respecting current national standard of table tennis ball,this paper presents an integrated and effective method for testing diameter,roundness and hardness of table tennis ball based on vis... Under the premise of fully respecting current national standard of table tennis ball,this paper presents an integrated and effective method for testing diameter,roundness and hardness of table tennis ball based on vision measurement. Firstly,camera calibration is performed by 40 mm gauge block to capture the images of table tennis ball in static and pressed state in an appropriate lighting condition. Then image binarization and extraction of image contour are carried out. The least square method is used to fit its center. Finally,the diameter,roundness and hardness are calculated. The measurement data are analyzed by using the method presented in this paper for table tennis ball with known parameter data and with unknown parameter data. Experimental results show that this method can improve measurement accuracy and provide a technical basis for the online testing and integration measurement of table tennis ball. 展开更多
关键词 table tennis ball DIAMETER roundness HARDNESS vision measurement
下载PDF
Research on Influence of Cutting Conditions on Roundness of Ultra-thin Wall Parts in Ultrasonic Vibration Cutting 被引量:1
4
作者 JIAO Feng 1, ZHAO Bo 1,2, LIU Chuan-shao 1, GAO Guo -fu 1 (1. Department of Mechanical Engineering, Jiaozuo Institute of Techno logy, Henan 454000, China 2. Institute of Mechanical Engineering, Shanghai Jiaotong University, Shanghai 200030, China) 《厦门大学学报(自然科学版)》 CAS CSCD 北大核心 2002年第S1期75-76,共2页
In the paper, the experimental researches were carr ie d out to discuss the roundness forming rule and the influence of cutting paramet ers on roundness by ultrasonic vibration cutting of the camera’s guiding drawtu ... In the paper, the experimental researches were carr ie d out to discuss the roundness forming rule and the influence of cutting paramet ers on roundness by ultrasonic vibration cutting of the camera’s guiding drawtu be with 47.75 mm diameter and 0.6~1.5 mm wall thickness. The research results s h ow that the roundness error of ultra-thin wall parts in ultrasonic vibration cu tting is only one third of that in common cutting. The relations between the rou ndness error and the cutting parameters behave as: (1) The roundness error in co mmon cutting decreases gradually with the rise of cutting speed, while in ultras onic cutting, the roundness changes not obviously till the cutting speed is up t o a value, which is nearly equal to one third of the critical velocity. Then the roundness of workpiece will begin to increase slowly. (2) The roundness error i ncreases along with the feed rate both in common cutting and ultrasonic cutting. (3) Within the range of cutting depth in experiment, the influence of cutting d epth on the roundness error is more obvious in common cutting than that in ultra sonic vibration cutting. The conclusions are useful in machining such precise ul tra-thin wall parts. According to the tests, the following conclusions can be o btained: 1) Compared with common cutting, ultrasonic cutting can decrease effect ively roundness error of the workpiece. Under the same condition, the roundness error of the ultra-thin wall part in ultrasonic turning is about one third of t hat in common cutting. 2) In common cutting, cutting depth and feed rate have mu ch influence on the roundness and the influence of cutting velocity is little. W hile in ultrasonic cutting, the roundness was influenced heavily only when feed rate is more than 0.1 mm/r and cutting speed is more than 1/3 of the critical ro tation speed, cutting depth has little influence on the roundness in the experim ent. 3) Kerosene-oil is an optimum cutting fluid in machining ultra-thin wall workpiece. 4) To machine the ultra-thin wall precision part, ultrasonic cutting is the perfect method which can decrease the roundness error effectively an d ensure high quality of the surface. 展开更多
关键词 ultra-thin wall part ultrasonic vibration cutt ing roundness guiding drawtube
下载PDF
Roundness error evaluation by minimum zone circle via microscope inspection
5
作者 姜黎 张之敬 +2 位作者 吴伟仁 金鑫 节德刚 《Journal of Beijing Institute of Technology》 EI CAS 2013年第2期185-190,共6页
Utilizing the convex hull theory, a novel minimum zone circle (MZC) method, named im- proved minimum zone circle (IMZC) was developed in this paper. There were three steps for IMZC to evaluate the roundness error.... Utilizing the convex hull theory, a novel minimum zone circle (MZC) method, named im- proved minimum zone circle (IMZC) was developed in this paper. There were three steps for IMZC to evaluate the roundness error. Firstly, with the convex hull algorithm, data points on the circle contour were categorized into two sets to determine two concentric circles which contained all points of the contour. Secondly, vertexes of the minimum circumscribed circle and the maximum inscribed circle were found out from the previously determined two sets, and then four tangent points for de- termining the two concentric circles were also found out. Lastly, according to the evaluation using the MZC method, the roundness error was figured out. In this paper l IMZC was used to evaluate roundness errors of some micro parts. The evaluation results showed that the measurement precision using the IMZC method was higher than the least squared circle (LSC) method for the same set of data points, and IMZC had the same accuracy as the traditional MZC but dramatically shortened com- putation time. The computation time of IMZC was 6. 89% of the traditional MZC. 展开更多
关键词 microscope inspection roundness error minimum zone circle (MZC) convex hull
下载PDF
Body Roundness Index Is Significantly Associated with Prehypertension and Hypertension in Nonobese Chinese Subjects
6
作者 LIU Xing Zhen QIAN Jian Dong +6 位作者 LI Hui Hua WANG Li Jun WU Min Kui WANG Qian PAN Ting Yu LIU Lian Yong ZOU Da Jin 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2019年第11期854-859,共6页
Prehypertension and hypertension have been considered significant public health issues worldwide[1].Disproportionate body fat distribution(excess fat stored in the liver and visceral compartment)is a well-established ... Prehypertension and hypertension have been considered significant public health issues worldwide[1].Disproportionate body fat distribution(excess fat stored in the liver and visceral compartment)is a well-established risk factor for prehypertension/hypertension[2].However,the most commonly used anthropometric indicators,such as body mass index(BMI)and waist circumference(WC)。 展开更多
关键词 BMI Body roundness Index Is Significantly Associated with Prehypertension and Hypertension in Nonobese Chinese Subjects
下载PDF
Uncertainty Calculation of Roundness Assessment by Automatic Differentiation in Coordinate Metrology
7
作者 林家春 Michael Krystek 石照耀 《Journal of Measurement Science and Instrumentation》 CAS 2010年第3期224-227,共4页
Reomtly, Coordinate bieasuring Machines (CMMs) are widely used to measure roundness errors. Roundness is calculated from a large number of points collected from the profiles of the parts. According to the Guide to t... Reomtly, Coordinate bieasuring Machines (CMMs) are widely used to measure roundness errors. Roundness is calculated from a large number of points collected from the profiles of the parts. According to the Guide to the Expression of Uncertainty in Measta- meat (GUM), all measurement results must have a stated uncertainty associated the titan. However, no CMMs give the uncertainty value of the roundness, because no suitable measrement uncertainty calculation procedure exists. In the case of roundness raeasurement in coordinate metrology, this paper suggests the algorithms for the calculation of the measurement uncertainty of the roudness deviation based on the two mainly used association criteria, LSC and MZC. The calculation of the sensitivity coefficients for the uncertainty calculatiion can be done by autnatic differentiation, in order to avoid introducing additional emars by the traditional difference quotient approxima- tions. The proposed methods are exact and need input data only as the nrasured coordinates of the data points and their associated un- certainties. 展开更多
关键词 raeasurement uncertainty roundness automatic diferentiation
下载PDF
Multi-Aspect Value of Measuring Systems and Methods Based on the Results of Roundness Measurements
8
作者 Miodrag Hadzistevic Imre Nemedi +2 位作者 Milenko Sekulic Martin Bosak Janko Hodolic 《Journal of Mechanics Engineering and Automation》 2012年第8期514-530,共17页
The increase of quality consciousness brings about the growth of significance of metrological systems. Besides the significance, the level of automatization, flexibility, accuracy, et al. have advanced. The modern mea... The increase of quality consciousness brings about the growth of significance of metrological systems. Besides the significance, the level of automatization, flexibility, accuracy, et al. have advanced. The modern measuring systems are constructed so that nearly all necessary dimensional characteristics can be measured with them. However, conventional measuring systems are provided for particular mode measurements. This research paper presents and compares several conventional and modem measuring systems and methods. The measured value is roundness, one of the basic shapes of cross section in mechanical engineering. This paper arises in search of answers for the question whether conventional measuring techniques and equipments are made redundant because of the modern ones. In what segments and in which criterion are modem methods preferable? 展开更多
关键词 Measuring systems roundness V-block method coordinate measuring machine (CMM) rotational datum method(RDM).
下载PDF
Vibration analysis of a single row angular contact ball bearing with the coupling errors including the surface roundness and waviness 被引量:5
9
作者 LIU Jing PANG RuiKun +2 位作者 XU YaJun DING ShiZhao HE QuBo 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2020年第6期943-952,共10页
Roundness and surface waviness are main manufacturing errors on the components of single row angular contact ball bearings(ACBBs).An analytical study for vibrations of the ACBBs with coupling errors including the roun... Roundness and surface waviness are main manufacturing errors on the components of single row angular contact ball bearings(ACBBs).An analytical study for vibrations of the ACBBs with coupling errors including the roundness and waviness can be useful for the vibration control of the rotating machinery.However,most previous works only focused on the single error modelling method.In this paper,an improved time dependent displacement excitation(TDDE)model is proposed to consider the coupling errors including the roundness and waviness on the inner and outer races of an ACBB.The TDDE model for the roundness and waviness is established by using a combination of several sinusoidal functions.A dynamic model in the previous study is improved to consider the influences of coupling errors including the roundness and waviness.The Hertzian contact theory and Dowson’s method are adopted to calculate the bearing contact stiffness.The time-and frequency-domain vibrations for the experimental and simulation results are compared to show some model validation.The influences of roundness orders and waviness amplitudes on the vibrations of the ACBB are analysed.The obtained results show that the coupling errors including the roundness and waviness have some influence on the time-domain impulse waveform and frequency-domain spectrum characteristics of the bearing accelerations.The differences of the vibrations between the coupling errors and sing error are from 4%to 42%.This paper can provide a useful guidance for the accurate diagnosis of surface imperfections in the ACBBs. 展开更多
关键词 angular contact ball bearing(ACBB) roundness error waviness error VIBRATION dynamic model
原文传递
Prediction of product roughness,profile,and roundness using machine learning techniques for a hard turning process 被引量:2
10
作者 Chunling Du Choon Lim Ho Jacek Kaminski 《Advances in Manufacturing》 SCIE EI CAS CSCD 2021年第2期206-215,共10页
High product quality is one of key demands of customers in the field of manufacturing such as computer numerical control(CNC)machining.Quality monitoring and prediction is of great importance to assure high-quality or... High product quality is one of key demands of customers in the field of manufacturing such as computer numerical control(CNC)machining.Quality monitoring and prediction is of great importance to assure high-quality or zero defect production.In this work,we consider roughness parameter Ra,profile deviation Pt and roundness deviation RONt of the machined products by a lathe.Intrinsically,these three parameters are much related to the machine spindle parameters of preload,temperature,and rotations per minute(RPMs),while in this paper,spindle vibration and cutting force are taken as inputs and used to predict the three quality parameters.Power spectral density(PSD)based feature extraction,the method to generate compact and well-correlated features,is proposed in details in this paper.Using the efficient features,neural network based machine learning technique turns out to be able to result in high prediction accuracy with R2 score of 0.92 for roughness,0.86 for profile,and 0.95 for roundness. 展开更多
关键词 Computer numerical control(CNC)machining Quality prediction Roughness parameter Profile deviation roundness deviation Machine learning
原文传递
Three-Probe Error Separation with Chromatic Confocal Sensors for Roundness Measurement 被引量:6
11
作者 Jiao Bai Yingzuo Wang +3 位作者 Xiaohao Wang Qian Zhou Kai Ni Xinghui Li 《Nanomanufacturing and Metrology》 2021年第4期247-255,共9页
In this study,three-probe error separation was developed with three chromatic confocal displacement sensors for roundness measurement.Here,the harmonic suppression is discussed first to set suitable orientation angles... In this study,three-probe error separation was developed with three chromatic confocal displacement sensors for roundness measurement.Here,the harmonic suppression is discussed first to set suitable orientation angles among three sensors.Monte Carlo simulation is utilized to test the error separation and optimize the orientation angles and off-axial distance.The experimental setup is established using chromatic confocal sensors with a precise rotary platform.The experimental results show that the measured roundness with an orientation-angle combination of(0°,90.1°,and 178.6°)is much better than that of another nonoptimal selection(0°,90.4°,and 177.4°).The roundness error is only 0.7%between the proposed measurement system and an expensive ultraprecision roundness meter.Furthermore,it is proven that the eccentricity distance should be decreased as small as possible to improve the measurement accuracy.In sum,this paper proposes a feasible method for roundness measurement with reliable simulations,easily integrated sensors,and an ordinary precision rotary platform. 展开更多
关键词 roundness measurement Three-probe error separation Chromatic confocal sensor Monte Carlo simulation
原文传递
DEM study on effect of particle roundness on biaxial shearing of sand 被引量:2
12
作者 Mengmeng Wu Linghong Xiong Jianfeng Wang 《Underground Space》 SCIE EI 2021年第6期678-694,共17页
In this study,discrete element method(DEM)simulations of a biaxial test were used to examine the effect of particle roundness on the mechanical behavior of sands at both the macro and micro scales.First,a stack of mic... In this study,discrete element method(DEM)simulations of a biaxial test were used to examine the effect of particle roundness on the mechanical behavior of sands at both the macro and micro scales.First,a stack of microcomputed tomography images were binarized,segmented,and labeled using advanced image processing and analysis techniques.Second,a spherical harmonic(SH)analysis,which involves a complete set of orthogonal functions,was implemented to rebuild the natural particle shape.Then,five templates of virtual particles were built in a DEM simulation,four of which were obtained from SH degrees of 3,8,12,and 15,and one template was an elementary sphere.A flexible membrane was numerically generated to allow the material to deform freely under a prescribed confining stress.Finally,the effect of particle roundness on the mechanical properties of granular materials was investigated and discussed.Two shear bands were found to intersect,forming an X shape in both the rotation and displacement fields.Moreover,a lower particle roundness results in higher deviatoric stress and stronger dilation in the volumetric change.A decrease in particle roundness leads to less rotation of particles despite a higher displacement value.In addition,a larger SH degree leads to smaller normalized contact forces of the particles.This implies that decreasing the roundness results in higher anisotropy of the contact forces. 展开更多
关键词 Grain shape roundness Flexible membrane Spherical harmonic analysis Discrete element method
原文传递
On-Line Measurement Method for Diameter and Roundness Error of Balls 被引量:4
13
作者 Yindi Cai Bo Xie +1 位作者 Siying Ling Kuang-Chao Fan 《Nanomanufacturing and Metrology》 2020年第3期218-227,共10页
This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurement... This paper presents an on-line measurement method for the diameter and roundness error of balls.An easy-installation rotary scanning system,which integrates the principles of the diameter and the roundness measurements,is constructed.The rotary scanning system consists of a rotary stage,a linear stage,and two sensors with a什at probe.Two sensors are initially installed on the linear stage and contact each other.The outputs of two sensors are reset to zero at first.The ball is then mounted on the rotary stage and positioned between two flat probes.The variations of the diameter and the roundness error of the ball at each angular position can be directly recorded by two sensors when the ball is rotated by the rotary stage.Substituting the outputs of two sensors into the proposed mathematical models,the diameter and roundness error can be evaluated.The effects of the alignment error induced by the spindle error of the rotary stage and the titling error and the eccentric error of the ball on the measurement accuracy can be self-separated in the proposed on-line measurement method.A series of experiments are carried out to verify the effectiveness and the capability of the proposed on-line measurement method and the designed rotary scanning system.The designed system is easy to construct both in the laboratory environment and the factory field. 展开更多
关键词 On-line measurement DIAMETER roundness error Alignment error
原文传递
Numerical simulation of inlet placement on sewage characteristics in the rounded square aquaculture tank with single inlet
14
作者 Xiaozhong REN Yixuan HU +5 位作者 Yinxin ZHOU Shupeng DU Wei SUN Hangfei LIU Chenxu ZHAO Ying LIU 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2024年第4期1359-1382,共24页
To improve the self-cleaning ability of aquaculture tank and the efficiency of circulating water,physical and numerical experiments were conducted on the influence of inlet structure on sewage discharge in a rounded s... To improve the self-cleaning ability of aquaculture tank and the efficiency of circulating water,physical and numerical experiments were conducted on the influence of inlet structure on sewage discharge in a rounded square aquaculture tank with a single inlet.Based on the physical model of the tank,analysis of how inlet structure adjustment affects sewage discharge efficiency and flow field characteristics was conducted to provide suitable flow field conditions for sinkable solid particle discharge.In addition,an internal flow field simulation was conducted using the RNG k-εturbulence model in hydraulic drive mode.Then a solid-fluid multiphase model was created to investigate how the inlet structure affects sewage collection in the rounded square aquaculture tank with single inlet and outlet.The finding revealed that the impact of inlet structure is considerably affecting sewage collection.The conditions of C/B=0.07-0.11(the ratio of horizontal distance between the center of the inlet pipe and the tank wall(C)to length of the tank(B))andα=25°(αis the angle between the direction of the jet and the tangential direction of the arc angle)resulted in optimal sewage collection,which is similar to the flow field experiment in the rounded square aquaculture tank with single inlet and outlet.An excellent correlation was revealed between sewage collection and fluid circulation stability in the aquaculture tank.The present study provided a reference for design and optimization of circulating aquaculture tanks in aquaculture industry. 展开更多
关键词 rounded square aquaculture tank sewage collection characteristic inlet structure computational fluid dynamic
下载PDF
Roundness measurement of cigarette based on visual information
15
作者 Jun-Li Cao Ju-Feng Li Teng-Da Lu 《Advances in Manufacturing》 SCIE CAS CSCD 2017年第2期177-181,共5页
Roundness is defined as the degree that the cross section of an object is close to a theoretical circle. In the cigarette production process, the quality and production efficiency of a cigarette are directly affected ... Roundness is defined as the degree that the cross section of an object is close to a theoretical circle. In the cigarette production process, the quality and production efficiency of a cigarette are directly affected by the roundness of the un-cut cigarette. To improve the current measurement method using a charge-coupled device (CCD) sensor and measure the roundness of cigarettes in the production line, a visual detection system composed of an industrial camera and a structural light is developed. The system's roundness-calculation method is closer to the real environment of the cigarette roundness. In this visual system, the line-structure light shines on the cigarette with a fixed angle and height in a longitudinal section, forming a crescent-shaped spot when the industrial camera cannot capture the cigarette's end surface. Then, the spot is analyzed using image-processing techniques, such as a median filter and ellipse fitting, after the industrial camera captures the spot. The system with a non-contact measurement style can meet the requirements of on-line cigarette detection with stable results and high precision. 展开更多
关键词 roundness measurement Ellipse fitting Image processing Visual detection system
原文传递
基于混沌遗传算法的圆度误差测量 被引量:2
16
作者 王伯平 王薇 +3 位作者 孙大刚 阎献国 都丽娜 Bo-ping Da-gang Xian-guo Li-na 《计量学报》 CSCD 北大核心 2009年第6期-,共3页
提出了一种基于混沌遗传算法的计算圆度误差的新方法.它利用混沌优化方法的遍历性和随机性,通过混沌扰动操作可克服传统遗传算法中的早熟问题,确保算法的全局收敛性.该方法满足最小条件原理,其计算结果的精确度非常高,理论上可以获得全... 提出了一种基于混沌遗传算法的计算圆度误差的新方法.它利用混沌优化方法的遍历性和随机性,通过混沌扰动操作可克服传统遗传算法中的早熟问题,确保算法的全局收敛性.该方法满足最小条件原理,其计算结果的精确度非常高,理论上可以获得全局最优解.实例计算表明,这种算法简单明确,具有精度高、收敛速度快、易于计算机程序实现和推广应用等特点. Abstract: A new method for calculating the roundness error based on chaos genetic algorithms is proposed. The system utilizes the ergodicity and randomness of chaos optimal method and by means of chaos stir operation, which can overcame the problem of premature convergence in traditional genetic algorithms and ensured an convergence of the algorithms. The method satisfies the principle of the least condition, the precision of calculating result is very high and can find .the global optimal solution. An actual calculated example showed that this method is simple and clear and it has features of high precision and fast convergent speed as well as using computer easily and popularizing application easily. 展开更多
关键词 混沌遗传算法 圆度误差测量 GENETIC ALGORITHMS Based roundness ERROR GENETIC ALGORITHMS premature convergence 计算结果 roundness ERROR high precision 混沌优化方法 传统遗传算法 traditional application 全局最优解 全局收敛性 new method operation 最小条件 推广应用
下载PDF
溪洛渡左岸发电机转子组装技术 被引量:3
17
作者 李成峰 《应用能源技术》 2013年第6期43-46,共4页
文中详细论述溪洛渡左岸首台770MW发电机转子安装技术。在借鉴三峡机组转子安装经验基础上,对磁轭键槽板焊接变形控制、转子磁轭加热方式,转子圆度调整方案等关键环节提出具体改进措施。保证溪洛渡转子的安装质量。
关键词 转子 磁轭 键槽板 圆度(key WORDS ROTOR RIM roundness)
下载PDF
Interaction of subway LIM vehicle with ballasted track in polygonal wheel wear development 被引量:9
18
作者 Ling Li Xin-Biao Xiao Xue-Song Jin 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2011年第2期297-307,共11页
This paper develops a coupled dynamics model for a linear induction motor (LIM) vehicle and a subway track to investigate the influence of polygonal wheels of the vehicle on the dynamic behavior of the system. In th... This paper develops a coupled dynamics model for a linear induction motor (LIM) vehicle and a subway track to investigate the influence of polygonal wheels of the vehicle on the dynamic behavior of the system. In the model, the vehicle is modeled as a multi-body system with 35 degrees of freedom. A Timoshenko beam is used to model the rails which are discretely supported by sleepers. The sleepers are modeled as rigid bodies with their vertical, lateral, and rolling motions being considered. In order to simulate the vehicle running along the track, a moving sleeper support model is introduced to simulate the excitation by the discrete sleeper supporters, in which the sleepers are assumed to move backward at a constant speed that is the same as the train speed. The Hertzian contact theory and the Shen– Hedrick–Elkins’ model are utilized to deal with the normal dynamic forces and the tangential forces between wheels and rails, respectively. In order to better characterize the linear metro system (LMS), Euler beam theory based on modal superposition method is used to model LIM and RP. The vertical electric magnetic force and the lateral restoring force between the LIM and RP are also taken into consideration. The former has gap-varying nonlinear characteristics, whilst the latter is considered as a constant restoring force of 1 kN. The numerical analysis considers the effect of the excitation due to polygonal wheels on the dynamic behavior of the system at different wear stages, in which the used data regarding the polygonal wear on the wheel tread are directly measured at the subway site. 展开更多
关键词 Linear induction motor Uneven wear Wheel out of roundness Vehicle-track coupling dynamics
下载PDF
Influence of coke structure on coke quality using image analysis method 被引量:3
19
作者 B.Ghosh B.K.Sahoo +4 位作者 B.Chakrabortv K.K.Manjhi S.K.Das J.N.Sahu Atul K.Varma 《International Journal of Coal Science & Technology》 EI 2018年第4期473-485,共13页
The quality of coke affects the performance of the blast furnace, factors affecting coke quality include coal properties, coal charge granulometry and carbonization conditions. The coke properties in elude the size an... The quality of coke affects the performance of the blast furnace, factors affecting coke quality include coal properties, coal charge granulometry and carbonization conditions. The coke properties in elude the size analysis, cold strength (Micum Indices-M4(). MI0) and hot strength (Coke Reactivity Index-CRI, Coke Strength after Reaction-CSR) properties and structural properties such as coke structure and texture. Structural properties comprise the porosity, pore-cell wall thickness and pore sizes, while textures consist of the carbon forms in the coke. In present work, advanced method such as image analysis method was used to interpret coke microstructure. Conventional methods such as determination of coke porosity by measurement of real and apparent density and mercury porosimetry have a number of limitations. Coke size, magnification, number of image frames captured, process of pellet preparations and coke properties such as M4(), M|0, CRI and CSR (low, medium and high values) were taken as variables for experimental purposes. The coke structure parameters such as porosity, length, perimeter, breadth, roundness, pore-wall thickness and pore size distribution of the pores were determined by image analysis method. This method provided average porosity in addition to pore-wall thickness and pore-size distribution. The pore wall thickness measuremenl by image analysis method provided significant correlations with M40, CRI and CSR values. This explained the usability of image analysis for coke structure measurement. 展开更多
关键词 Image analysis COKE STRUCTURE POROSITY Micro STRUCTURE roundness PORE WALL thickness
下载PDF
An approach for wellbore failure analysis using rock cavings and image processing 被引量:1
20
作者 Christopher Skea Alireza Rezagholilou +2 位作者 Pouria Behnoud Far Raoof Gholami Mohammad Sarmadivleh 《Journal of Rock Mechanics and Geotechnical Engineering》 CSCD 2018年第5期865-878,共14页
There have been interests to link different cuttings/cavings to various wellbore failure types during drilling. This concept is essential when caliper and image logs are not available. Identification ofwellbore failur... There have been interests to link different cuttings/cavings to various wellbore failure types during drilling. This concept is essential when caliper and image logs are not available. Identification ofwellbore failure during drilling gives more chance of immediate actions before wireline logging program. In this paper, an approach was presented based on the image processing of ditch cuttings. This approach uses the sphericity and roundness of cuttings as input data to classify caving types and subsequently deter- mine the dominant failure type. Likewise, common definitions of cavings were discussed initially before a new criterion is suggested. This quantitative criterion was examined by observations from caliper and acoustic image logs as well. The proposed approach and criterion were implemented on ditch cuttings taken from a well in Western Australia. Results indicate that the primary failure is shear failure (breakout) due to high levels of angular cavings. However, another failure due to the fluid invasion into pre-existing fractures was also recorded by blocky cavings. 展开更多
关键词 Caving shape CUTTINGS DRILLING Image analysis Wellbore failures roundness SPHERICITY
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部