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Surface Roughness and roundness of Bearing Raceway Machined by Floating Abrasive Polishing and Their Effects on Bearing's Running Noise

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Chinese Journal of Mechanical Engineering 2014年第3期27卷 543-550页

作者： PANG Guibing QI Xuezhi MA Qinyi ZHAO Xiujun WEN Chunsheng XU Wenji PENG Yanping School of Mechanical Engineering and Automation Dalian Polytechnic University Dalian Wazhou Precision Motor & Automobile Bearing Co. ltd School of Mechanical Engineering Dalian University of Technology

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.

关键词： surface roughness roundness polishing lapping bearing raceway noise

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DEM study on effect of particle roundness on biaxial shearing of sand

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Underground Space 2021年第6期6卷 678-694页

作者： Mengmeng Wu Linghong Xiong Jianfeng Wang Department of Architecture and Civil Engineering City University of Hong KongHong KongChina Shenzhen Research Institute of City University of Hong Kong ShenzhenChina

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.

关键词： Grain shape roundness Flexible membrane Spherical harmonic analysis Discrete element method

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Insight into deformation allocation in the multi-pass roll forming of a double-walled brazed tube

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Advances in Manufacturing 2023年第4期11卷 567-586页

作者： Meng-Meng Liu Yu-Li Liu Heng Li State Key Laboratory of Solidification Processing School of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an710072People’s Republic of China

Deformation allocation is an important factor that affects 720°curling forming from copper-coated steel strips to double-walled brazed tubes(DWBTs).In this study,four schemes of deformation allocation,considering different weights of the total feed distance,are proposed,and a 3D finite element(FE)model of the multi-pass roll forming process for DWBT is developed and verified to investigate the cross-sectional evolution and deformation features.The results show the following.(i)In the 720°curling forming process from the steel strip into double-walled tubes,the curvature of the formed circular arc initially increases and then remains stable with roll forming,and the inner and outer tubes of the DWBT are formed in the third and fifth forming passes.Size forming can eliminate the gap between the double walls and improve the overall roundness.(ii)For different deformation allocations,the cross-sectional profiles of the roll-formed parts exhibit a discrepancy,and the deformation amount varies with the roll-forming process.The deformation amount in Scheme three is the maximum,and the cross-sectional profile deviates significantly from the ideal shape and fails to form a DWBT,which indicates that the deformation allocation is unsuitable.(iii)The roundness of the outer tube is better than that of the inner tube.Therefore,the roundness of the inner tube is the key to restricting the forming accuracy of the DWBT.Compared with Schemes one and two,Scheme four with a linear allocation of the total feed distance exhibits the best roundness,and the deformation allocation is reasonable;i.e.,when the contact points between the rollers and steel strip are in a straight line,the roundness of the DWBT is in good agreement with the ideal condition.

关键词： Double-walled brazed tube(DWBT) Multi-pass roll forming Deformation allocation Cross-sectional profile roundness

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Experimental investigation on debris flow resistance and entrainment characteristics:effects of the erodible bed with discontinuous grading

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Journal of Mountain Science 2022年第8期19卷 2397-2419页

作者： LI Pu WANG Jia-ding HU Kai-heng QIU Hai-jun XIE Jia-lin State Key Laboratory of Continental Dynamics/Department of Geology Northwest UniversityXi'an 710069China Key Laboratory of Mountain Hazards and Earth Surface Processes Chinese Academy of SciencesChengdu 610041China Institute of Mountain Hazards and Environment Chinese Academy of Sciences&Ministry of Water ConservancyChengdu 610041China College of Urban and Environmental Sciences Northwest UniversityXi'an 710127China

Debris flow deposits in natural channels typically have a wide grain size distribution(GSD).The effects of bed sediment GSD on the basal entrainment rate are neglected in current debris flow erosion models.Field investigations have detected three different vertical graded bedding structures:normal,inverse,and mixed-gradation,characterized by discontinuous gradation sediment and almost without intermediate-sized particles.This study conducted small-scale flume experiments to investigate the debris flow resistance forces and entrainment characteristics by incorporating the effects of discontinuous grading bed sediments.Discontinuous graded bed sediments with varying fine particle content,volumetric water content(VWC),and roundness were designed for comparison.Debris flow resistance in erodible beds generally increased in the group with gravel of larger-sized coarse particle,lower roundness,and higher bed sediment VWC.For discontinuous grading bed sediment,the entrained depths increased in the group with gravel of smaller coarse particle sizes,larger amounts of fine particles,and higher sediment roundness,and decreased with larger VWCs.This abnormality may be attributed to the disproportionately large effects of viscous flow resistance in our small-scale flume tests.The maximum erosion rates of the continuous bed sediment were higher than those of the corresponding discontinuous bed sediment with the same maximum coarse gravel size.This is because,for discontinuous grading bed sediments,localized failure of intermediate-sized sediment grains may cause a large-scale collapse of the solid grain skeleton and enhance basal entrainment rates.A revised formula for calculating the debris flow entrainment rate is proposed by incorporating the kurtosis coefficient,which describes the distribution of discontinuous bed sediments and fine particle content.Our revised formula could facilitate an elaborate estimation of basin erosion and sediment runoff and reveal the development and recession of debris flow fans.

关键词： Debris flow Resistance force Entrainment characteristic Discontinuous gradation roundness Entrainment model

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Research on Influence of Cutting Conditions on roundness of Ultra-thin Wall Parts in Ultrasonic Vibration Cutting

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厦门大学学报（自然科学版） 2002年第S1期41卷 75-76页

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)

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

关键词： ultra-thin wall part ultrasonic vibration cutt ing roundness guiding drawtube

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Shear behaviours of cohesionless mixed soils using the DEM:The influence of coarse particle shape

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Particuology 2021年第2期19卷 151-165页

作者： Yangui Zhu Jian Gong Zhihong Nie School of Civil Engineering Central South UniversityChangsha 410075China

The coarse particles in mixed soils can be cobbles or gravels,with the main difference being their roundness(an indicator describing particle shape characteristics at an intermediate scale).The influence of coarse particle shape(i.e.,roundness)on the macroscopic and microscopic shear behaviours of cohesionless mixed soils with various fines contents(FCs)was investigated via the discrete element method in this study.The shapes of coarse particles were formed using the rotation-invariant spherical harmonic method proposed by previous investigators.An equation was proposed to predict the initial void ratios of samples in this study.A decrease in the roundness of coarse particles can increase the peak friction angle(FC≤40%)and critical friction angle(FC≤30%).As the roundness of coarse particles decreases,the peak dilatancy angle initially increases and then decreases(FC≤20%).Furthermore,it was found that the roundness of coarse particles hardly affects the classification of cohesionless mixed soils,as determined by probing the percentage contributions of coarse-coarse,coarse-fine,and fine-fine contacts.When cohesionless mixed soils change from an underfilled structure to an interactive-underfilled structure at the critical state,the main forms of coarse-coarse contacts were discovered.Additionally,the force-fabric anisotropy mechanisms of the influences of the roundness and rolling resistance coefficient of coarse particles on the shear strengths of cohesionless mixed soils were found to be different.

关键词： Cohesionless mixed soils Particle shape roundness Shear behaviours Discrete element method

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An approach for wellbore failure analysis using rock cavings and image processing

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Journal of Rock Mechanics and Geotechnical Engineering 2018年第5期10卷 865-878页

作者： Christopher Skea Alireza Rezagholilou Pouria Behnoud Far Raoof Gholami Mohammad Sarmadivleh Department of Petroleum Engineering Curtin University Department of Petroleum Engineering Amirkabir University of Technology

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.

关键词： Caving shape Cuttings Drilling Image analysis Wellbore failures roundness Sphericity

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Influence of coke structure on coke quality using image analysis method

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International Journal of Coal Science & Technology 2018年第4期5卷 473-485页

作者： B.Ghosh B.K.Sahoo B.Chakrabortv K.K.Manjhi S.K.Das J.N.Sahu Atul K.Varma Research & Development Centre for Iron and Steel Steel Authority of India Limited (SAIL)RanchiJharkhand 834002India Institute of Chenlical Technology Faculty of ChemistryUniversity of Stuttgart70550 StuttgartGermany Coal Geology and Organic Petrology Laboratory Department of Applied GeologyIITIndian School of Mines (ISM)Dhanbad 826004India South Ural State University 76Lenin Aven.ChelyabinskRussia 454080

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.

关键词： Image analysis Coke structure Porosity Micro structure roundness Pore wall thickness

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The Effect of Grain Properties for Artificial Bedload Supply

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四川大学学报（工程科学版） 2005年第S1期37卷 30-33页

作者： Markus PROMNY Inst.of Hydrosciences Gennan Armed Forces Univ.Munich85577 NeubibergGermany

The German Armed Forces University in Munich has conducted experiments in a laboratory flume to determine the influence of roundness on bed load transport.The investigations were assigned by the German Federal Institute of Hydrology (BIG),with a focus on incipient motion,transport velocity and the depth of mixing into the riverbed. The results of the experiments show that the transport velocity of angular graim is lower and the critical shear stress for incipient motion is slightly higher than of well-ro...

关键词： bed load supply bed load transport grain properties roundness tracer experiments incipient motion transport velocity

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基于混沌遗传算法的圆度误差测量

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计量学报 2009年第6期30卷 -页

作者：王伯平王薇孙大刚阎献国都丽娜 Bo-ping Da-gang Xian-guo Li-na 太原科技大学山西太原030024 太原高新技术开发区山西太原030006

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... 详细信息

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.

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

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