bluuebunny/crossref_metadata_2025 huggingface dataset:
Roughness Detection Based on 3D Shape Reconstruction of Workpiece Surface Micro-Vision Image
Authors: Zheng Jian Ming , Guo Bian , Yang Ming Shun , Li Yan , Wang X.N.
Published: December 2010

The Shape from Shading (SFS) method is adopted to detect the micro-topography and roughness parameter of machining surface based on computer micro-vision in this paper. According to the reflection features of micro metal surface, the illumination model is improved by the weighting superposition of the diffuse component of the simplified Oren-Nayar model and the specular component of the Torrance-Sparrow model. The minimized calculation method of SFS is given based on the improved illumination model. The 3D topography reconstruction and the roughness parameter detection of the turning surface are accomplished. The experimental results show that this method can rapidly realize the accurate detection of surface roughness parameter, and provides new ideas and methods for detection the roughness on-line in machining process.
Experimental Study on Cutting Force in Machining Nickel Base Superalloy
Authors: Wang X.Y. , Pang S.Q. , Yu Q.X.
Published: December 2010

Studies on cutting force lead an extremely important guiding significance in the actual producing. Nickel base superalloy is widely in the manufacture of components for some important industrial areas, because of their ability to retain high-strength at elevated temperatures. It possesses excellent performance as a class of advanced materials. Because of its very poor machinability, the study on cutting force in machining nickel-based superalloy in the actual production or scientific research is relatively less. In this paper, Author aim at two kinds of typical difficult-to-machining materials nickel base superalloy (GH4169, K24). Contrasting with other typical materials ,such as 45# steel and high strength steel 35CrMnSi，study the law of cutting force effected by cutting parameters under the conditions of turning . Intuitive analysis of cutting force changes with the cutting parameters, as well as these characteristics on three-axis force of each type of material, that is to improve its processability and to provide guidance to actual production has a positive significance.
Joining of Diamond Grains to Medium Carbon Steel with Ni-Base Powder during Laser Brazing
Authors: Yang Zhi Bo , Liu Ai Ju , Xu Jiu Hua
Published: December 2010

In order to develop new generation brazed Diamond grinding wheels, the joining experiments of Diamond super abrasive grains and medium carbon steel using the powder mixture of Ni-Cr alloy as active brazing alloy are carried out via laser in an argon atmosphere. The relevant characteristics of the special powder mixture, the microstructure of the interfacial region, which are both the key factors for determining the joining strength among the Diamond grains, the filler layer and the steel substrate, are investigated extensively by means of scanning electron microscope (SEM) and energy dispersion spectrometer (EDS), as well X-ray diffraction (XRD) analysis. The formation mechanism of carbide layers was discussed. All the results indicate that high strength bonding between diamond grits and the steel substrate has been successfully realized because the chromium in the Ni-based alloy segregated preferentially to the surface of the diamond to form a chromium-rich reaction product Cr3C2, and the bond between the alloy and the Diamond was established through the reaction product.
Simulation and Experiment of New Whole Vibrator for Ultrasonic Vibration Internal Grinding System
Authors: Yin Zhen , Li H. , Li Yan , Xie Ou
Published: December 2010

Based on designing problems of the vibrator composed by the transducer, horn and tool in the ultrasonic vibration internal grinding (UVG) system, a new whole vibrator design method were proposed. The model and harmonic analyses of the new whole vibrator were performed by FEM, the prototype of the new whole vibrator was tested by using impedance analyzer and PSV-400 laser Doppler vibrometer, the correctness of the finite element simulation results and the feasibility of the new whole vibrator design methods were verified.
Effects of Oscillation Frequency on the Tribological Properties of Self-Lubrication Spherical Plain Bearings with PTFE Woven Liner
Authors: Qiu Ming , Gao Z.L. , Yao S.J. , Chen Long
Published: December 2010

The working principle and performance characteristics of a self-made oscillation tribo-tester were introduced. Under different oscillation frequency and pressure conditions, the friction coefficient and linear wear of spherical plain bearings with polytetrafluoroethylene (PTFE) woven liner were investigated. By using scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), the wear mechanism of the spherical plain bearing was analyzed. The results indicate that with the oscillation frequency increases, the friction coefficient of spherical plain bearings decreased while the wear loss increased. In the high frequency of 4.8Hz, the reduction ranges of the friction coefficient is not obvious with the contact pressure increased, but the effect of contact pressure on the wear of the spherical plain bearing is great. During the experiment, adhesive wear, abrasive wear and spalling wear took place on the surfaces of woven liners.
Research on Robot Vision Technology Based on ARM and DSP for Age and Disabled Helping Robot
Authors: Wang C.Z. , Zhang Xiao Dong , Wu Xue Zhi
Published: December 2010

The robot vision technology designed to help the elderly and the disabled people are studied on a mobile robot in the thesis, and its robot vision system based on ARM and DSP is mainly designed, respectively. After hardware construction and software design, the experiments are taken to verify the feasibility of the application of the robot vision technology on the age and disabled helping robot.
Life Prediction of Bearings Based on Fuzzy Theory
Authors: Wang X.Q. , Cui F.K. , Wang G.B.
Published: December 2010

Based on the fuzzy theory and universal calculation equations, the mathematical model is established for predicting life of a bearing by analyzing various factors. And the fuzzy reliability life can be calculated according to the model. The case studies show that for the proposed method takes full consideration of all the influencing factors and their function of membership degree, the calculation results are very close to the actual ones.
Oxidation and Wear Resistance of Ni-Y2O3-ZrO2 Nanocomposite Coating Prepared by Ultrasonic Electrodeposition
Authors: Xue Yu Jun , Shen Chen , Li Ji Shun , Liu Yi
Published: December 2010

Ni-Y2O3-ZrO2 nanocomposite coating was prepared by co-deposition of nickel, Yttrium oxide (Y2O3) and zirconium oxide (ZrO2) nanoparticles using ultrasonic electrodeopsition. The surface morphology and composition of coatings were ananlyzed by an environmental scanning electron microscope (ESEM) and energy dispersive spectrometer(EDS). The high temperature oxidation, microhardness and wear resistance of the coatings were investigated. It is found that both the incorporation of nanoparticles and the use of ultrasonic could refine Ni crystal grains and improve properties of the coatings. The Ni-Y2O3-ZrO2 nanocomposite coating prepared with ultrasonic exhibits finer grains, higher microhardness and better oxidation and wear resistance.
The Suction Characteristics Simulation of Electromagnet Based on Maxwell
Authors: Cheng X.L. , An Lin Chao , Guo K.
Published: December 2010

This paper makes the analysis to magnetostatic field and transient of electromagnet by using Maxwell. The magnetic-flux density of electromagnet and the distribution map of magnetic induction intensity are obtained and it has been verified that the electromagnet can meet the first pilot valve's open and close completely under the essential security power equipment's condition by the magnetostatic field analysis. Dynamic characteristic of the electromagnet is obtained under the constant load, and has further confirmed the reliability of electromagnet by the transient analysis.
A New Method of CMM Inspect Path Planning for Precision Generalized Helicoid
Authors: Pan Wei Min , Yu Yong Jian , Li J.S. , Xu F.
Published: December 2010

The helical surfaces are widely applied to both power transmission and fluid compression or pumping. Helicoid is measured by digitized measurement with the coordinate measuring machine (CMM) in this paper. A numerical measuring method which is different from traditional measuring method for Helicoid is given. The Measuring process is illustrated in detail. At the same time, this method is proved effectiveness through a practical measuring example of an aerial part.
Development of On-Line Automatic Monitoring System for the Steel Belt Conveyor
Authors: Zhao S.S. , Guo B.J. , Yang X.
Published: December 2010

The on-line automatic monitoring system is self-developed for steel cord conveyor belt. It is based on weak-magnetic field constant nondestructive testing technologies and adopted the sensor array with horizontal and vertical transducers to fully guarantee the fault location accuracy and amplitude accuracy. The TCP and UDP network transport protocol is used in this system, which achieves the real-time communication, data saving and image reconstruction. Different feature fault signal of steel wire is extracted and identified automatically. So the quantitative detection and location detection are realized for various steel cord failures such as rope broken, rust corrosion, joint dislocation, crushed, tilt and so on.
Research on Cutting Performance of Graphite-Like Carbon Coated Tools in Dry Drilling of Ferrous Metal
Authors: Xiao Ji Ming , Li Yan , Bai L.J. , Yuan Qi Long , Zheng Jian Ming
Published: December 2010

The graphite-like carbon (GLC) coating was deposited onto high-speed steel (HSS) twist drills by magnetron sputter ion plating technique. The drilling tests were performed on the ferrous metal under dry cutting conditions. By the analysis and comparison of the flank wear and the drilling forces on drills, the cutting performance of GLC coated HSS tools was researched. The results show that GLC coating with high hardness and low friction coefficient, due to its good adhesion and match with HSS substrate, can significantly improve the cutting performance of HSS twist drills, prolong the tool life, decrease the drilling forces in drilling the ferrous metal. And its cutting performance is better than the hard coated drills in the lower speed, but its thermal stability is inferior to the hard coated drills in the higher speed.
New Method of Pre-Stress Hard Cutting for Screw Shaft
Authors: Ye Bang Yan , Liu Jian Ping , Qin Meng Yang , Zhang Cheng Zhong , Zhao Xue Zhi
Published: December 2010

The import mechanical components and burden part in aeronautic and automobile industry, such as screw shaft, aero-bearing and engine vane etc. are often found fatigue failure cased by their residual stress state on machined surface. Aiming at the problem, this paper presents a new green machining technology by integrating pre-stress cutting and hard machining method. The principle of pre-stress hard cutting of shaft part is introduced together with its implementary process in this paper. Pre-stress loading method on screw shaft is investigated and device for actualizing the process is designed. Experiment of pre-stress hard cutting is carried out for screw shaft with PCBN tool. The experimental results show that by using this method, residual compressive stress is got on machined surface and hence increase the quality and fatigue life of screw shaft.
Measuring and Monitoring System of Weighing Process for Liquid Material
Authors: Ku X.C. , Li Ji Shun , Ma Wei , Han Hong Biao
Published: December 2010

According to the characteristics and requirements of weighing process for liquid raw material, the system of data acquisition and control based on serial port communication is designed in this paper. The system adopts the modularizing distributed structure and the way of RS485 communication to ensure the reliable data transmitting between IPC (Industrial Personal Computer) and modules. Based on C++ Builder 6.0 and SQL Server 2000, the system not only implements the process control of weighing and blending, but also realizes the production data storage and management. This paper analyzes the system function structure, describes the method of communication and introduces the means of data management. The application result indicates that this system improves the production efficiency and stabilizes the production process.
Morphology and Microhardness of Nickel Electroformed under Vacuum-Degassing Conditions
Authors: Ming Ping Mei , Li Y.J. , Jiang W.J.
Published: December 2010

Ni deposits were prepared from a nickel sulfamate type electrolyte bath under vacuum-degassing and temperature-gradient conditions without any additives. Morphology and microhardness of the deposits obtained at the current density of 1A/dm2, 3A/dm2, 5A/dm2 and 7A/dm2 were examined and analyzed. Experimental results showed that the deposits obtained under vacuum-degassing and temperature-gradient conditions exhibited fewer pinhole defects and finer grain size comparing with those formed under conventional deposition conditions, and that the microhardness of the deposits was greater than that from conventional deposition conditions without additives while lower than that from conventional deposition conditions with additives. Under the vacuum-degassing conditions, the electroforms had remarkably smoother surface with fewer void defects and finer grain size, and considerably microhardness.
Dynamic Simulation of the Assembly Process of Spindle Box of Machine Tool
Authors: Li X.M. , Tong Y.F. , Hui An Feng
Published: December 2010

Based on the analyzed transmission process of spindle head and combined with the analyzed assembly process of spindle box, it determined the relationships of transmission and assembly between the various components of the spindle head. Firstly, using software of computer-aided design (UG6), it established a 3D parts library of spindle box of machine tool. Secondly, we had been developed dynamic simulation and power transmission simulation software of the assembly process of the spindle box of machine tool. It could realistically reproduce the disassembly process and the power transmission process of spindle box of machine tool when running the software. The software not only could be used for the old products to analysis and improvement, but also could be used for development of new products, and to some extent, the prototype could be replaced by it. The software was one of the essential tools for both the training of related employees and teaching of mechanical engineering students.
Research on Spindle Induction Motor Stator Flux Observer Algorithm
Authors: Xu F. , Zhang Ke , Cui Zheng Xing
Published: December 2010

In order to enhance observation accuracy of the spindle induction stator flux and decrease observation error which is influenced by temperature, frequency and magnetic path in operation process, a full order observer was used to observe stator flux. The change of stator flux observer which adopted u-i model and low pass filter estimation model observation error was analyzed when the parameters of motor changed through the mathematical model in the stationary coordinates. A method to determine the gain matrix of full order observer was presented. The results showed that the error changed with the changes of motor speed and torque. On the premise of assuring stability of the observer, according to different speed ranges, choosing the proper observer pole assignment, the method can be used to enhance the observation accuracy of stator flux at high speed, and it is also validated in the Matlab/Simulink condition. It is shown that it can improve observer accuracy of the induction motor stator flux effectively.
Method of Network Manufacturing Alliance Building Based on Service Resources Matching
Authors: Liu Yong , Li Yan , Li Shu Juan
Published: December 2010

Establishing effective network manufacturing alliance is the top priority of carrying out network manufacturing. Under circumstance of realizing resource sharing in network manufacturing, a method of network manufacturing alliance establishing based on service resource matching is put forward. Based on model of resource description framework, manufacturing service resource description model and matching strategy are established. According to describing feature of resource properties, matching of manufacturing resource and service resource is further transferred into corresponding qualitative and quantitative matching, similarity measuring methods of qualitative and quantitative properties in the matching process are presented respectively so as to accurately evaluate matching degree between manufacturing resource and service request. Availability of the model and its matching algorithm is verified by means of practical instances.
Study on Drilling Force of Pore for Hard-to-Cut Material
Authors: Tang Yong , Ye Bang Yan , Hu X.F. , Wu Qiang
Published: December 2010

This paper studies drilling force of pore for hard-cutting material based on theoretical and experimental investigation during pore drilling process. A coupled thermo-mechanical finite element model of metal pore drilling process was established. Some key techniques such as material model, chip separation and damage criteria and dynamic mesh self-adapting technology in the finite element simulation of metal cutting process were discussed in details. The paper simulated dynamically the chip formation of the twist drilling process in which rigid plastic material model was selected for workpieces and thermal rigid models for tools. The results indicate that the proposed finite element model is not only correct but also feasible in the prediction of the variations of drilling force and torque with amount of feed.
Mathematical Model of Hot-Roll On-Line Grinding Detecting System
Authors: Li Chang He , Hou Ya Li , Cai G.Q.
Published: December 2010

In the grinding process, in order to exert the hot-roll on-line grinding (HOG) better, the on-line profile measure (OPM) is required to work steadily and reliably. Nevertheless, owing to the bad environment in the hot-roll grinding, the high distinguish ability and the high security for the OPM technology are the most difficult problems at all the time.The research on this project fits for the development of on-line profile measure for hot stripe rolling grinding. Based on the thought of the operation principle and mathematical model and characteristic analysis, associated with the HOG system, the measurement can work numerically, high efficiently and accurately. The detecting system can inspect and diagnose the potential fault of the equipment, consequently the whole system can be assured to run in the best state.
Exploration into the Innovative Mode of Combining Learning with Researching and Production
Authors: Hong Hua Jie , Luo W. , Zhang Zhi Yong , Zhang Lian Chao , Fan Da Peng
Published: December 2010

It is proposed that the integration of learning, researching and production provides a good solution to the problem that higher education fails to offer qualified graduates demanded by machinery manufacturing industry. This paper first analyses the weakness of enterprises in scientific research and creativity and inexperience of higher education institutes in transferring scientific achievements, then some advice is given as to how to improve the innovative integration mode followed by some successful cases. At last it goes deeper into the future tendency of this mode.
Analysis on Forming Characteristics of Cup-Shaped Thin-Walled Inner Gear Spinning
Authors: Sun L.Y. , Ye Bang Yan , Xia Q.X. , Cheng Xiu Quan
Published: December 2010

Spin-forming is a new near net-shape forming process for cup-shaped thin-walled inner gear (CTIG). The CTIG spinning was investigated by numerical simulation and processing experiments. The results show that the compressive deformation along tangential direction on the internal surface of part leads to a reduction in root circle of spun part; and the local loading and friction work result in the nonuniform radial deformation on the external surface of spun part. For spin-forming of CTIG with a small number of teeth, the diameter reduction is feasible for improving the forming quality of tooth groove, while the nonuniform radial deformation would cause concaves on external surface of part. For spin-forming of CTIG with a large number of teeth, the diameter reduction is not conducive to removing the part from the mandrel.
Intelligent Design of a Mechanical Part Library in Real-Time Collaborative Design
Authors: Zhang Cheng Zhong , Ye Bang Yan , Liu L.
Published: December 2010

In this paper an automatic and intelligent mechanical part library design framework is proposed by utilizing network resources through real-time collaborative design. The proposed framework is based on the client/server network environment, where Web-based scripting language is used for parametric drive design. On the server side, according to the characteristics of parts and data structures, an extensible library of mechanical parts is established for users to use. Graphics data compression algorithms used in the collaborative design are also put on the system's server-side. The proposed framework provides an effective way with information sharing and flexibility for modern mechanical product design.
Profile Error Synthetic Prediction Model for One-Side Milling of Spatial Cams
Authors: Hu Zi Hua , Yi X. , Yuan Ju Long
Published: December 2010

Based on the detailed analysis of the one-side milling theory of the spatial cam, an error comprehensive prediction model of the contour normal deviation is proposed in this paper by applying the spatial meshing theory, the rotation transformation of tensor and Newton’s iteration. A computer simulation example is presented, and the results show the error prediction model can disclosure and predict the law of influence effectively, that the tool and installation inaccuracy produce the contour normal error during the one-side processing of the spatial cam. Consequently, a scientific proof has been supplied to improve the precision and quality of the one-side milling of the globoidal indexing cam.
An Operation Model of Fault Diagnosis Based on Grid
Authors: Chen Guo Rong , Yan Ping , Zhao J.
Published: December 2010

the fault diagnosis technologies have made great progress in recently years because some scholars focus their energies on the topic, but the application effect of the new technologies can’t reach the expectant result as before, the reason mainly dues to the knowledge sharing problem and the diagnosis cooperation problem that did not resolved well today. Aiming at the problems, an operation model of fault diagnosis based on grid was put forward out in the paper firstly; then studied the knowledge sharing principle and the methods of the grid, and the accessing strategy of resources and services based registering center in grid are brought forward. The analysis shows that the model is positive to resolve the problems of knowledge sharing and diagnosis cooperating.
The Study on Application of Worm’s Numerical Control Machining
Authors: Yu Ying Liang , Geng Zai Dan
Published: December 2010

One of the significant features of CNC technological superiority is in the practical applications, according to the necessary movement of processed parts required, we can use generating method to transform CNC machine tools and receive the desired results. This article discussed under the premise that lack of special equipment, transforming ordinary horizontal CNC milling to machine worm gear. The advantage of this numerical transformation approach is using the processing functions of thread and tapered thread instruction, skillfully translating into control of the CNC machining worm, expanding the CNC machining capabilities and the scope of practical application. Also apply the advantages of CNC technology, reduce or eliminate the accumulation of worm in the processing of pitch error which makes the worm processing precision and smoothness of worm drive better. This paper discussed the principles of numerical control transformation, transformation of milling machine structure and the conversion calculation of parameters in programming, analyzed the causes and processing effects of worm gear processing errors control and accuracy improving.
Real-Time B-Spline Interpolator with Look-Ahead Scheme for High-Speed CNC Machine Tools
Authors: Jin Yong Qiao , Wang Yu Han , Yang Jian Guo
Published: December 2010

NC tool paths of digital CAD models are currently generated as a set of discrete data points. The CNC interpolator must convert these points into continuous machine tool axis motions. In order to achieve high-speed and high-accuracy machining, the development of a real-time interpolation algorithm is really indispensable, which can deal with a large number of short blocks and still maintain smooth interpolation with an optimal speed. In this paper, a real-time local cubic B-spline interpolator with look-ahead scheme is proposed for consecutive micro-line blocks interpolation. First, the consecutive micro-line blocks that satisfy the bi-chord error constraints are fitted into a C1 continuous cubic B-spline curve. Second, machining dynamics and tool path contour constrains are taken into consideration. Third, local cubic B-spline interpolator with an optimal look-ahead scheme is proposed to generate the optimal speed profile. Simulation and experiment are performed in real-time environment to verify the effectiveness of the proposed method. Compared with the conventional interpolation algorithm, the proposed algorithm reduces the machining time by 70%.
An Online Modeling Method for Real-Time Thermal Error Compensation on High-Speed Machines Based on RBF Neural Network Theory
Authors: Zhang Hong Tao , Jiang Hui , Yang Jian Guo
Published: December 2010

This paper studies the modeling method based on RBF (Radial-Basis Function) neural network according to its learning ability, and a new neural network online model has been set up. The comparison and analysis result of the case studies shows that, when changing the working condition, the compensation effect of online modeling method is better than offline modeling method and the online model can better reflect the thermal characteristics of High-speed machine tool.
Research on Applying Image Processing Technology to Determine Center of Parts
Authors: Zheng You Yi , Rao Ji Lai , Wu Lei
Published: December 2010

The precision detection of machine parts is an important part of manufacturing, which guarantees the quality for products. Image processing technology is a new testing method of precision which opens a new way for the non-contact detection. Its application is more widely with the continuous development of image processing technology. You need a comparative basic point if it needs a comparative analysis with the ideal conditions parts when it’s necessary to detect a part. In this paper, it mainly analyzes the determination of logarithmic spiral surface couplings center points.
Research and Development of Ultrasonic Vibration Internal Grinding Technology
Authors: Li Hua , Zhang Z.W. , Yin Zhen
Published: December 2010

In this paper, the background of ultrasonic vibration internal grinding (UIG) technology was described; the main parameters of the UIG technology were summarized. The recent development of the UIG mechanism, system and ultrasonic vibration internal honing technology was overviewed. The development trend and future prospect of the UIG technology were proposed based on above analysis.
The Machined Surface Residual Stress of Nano-Ceramics with Two-Dimensional Ultrasonic Vibration Assisted Grinding
Authors: Zhang X.Q. , Zhao Chong Yang , Du Bao Yu
Published: December 2010

Surface plastic deformation form and residual stress distribution of nano-ceramics machined by ordinary grinding and two-dimensional ultrasonic grinding respectively were investigated. The obtained results show that machined surface residual stress in the two grinding modes is extrusion stress, and it decreased with the increasing of grinding depth. But the decrease of residual stress under two-dimensional ultrasonic grinding is less than that under normal grinding. In addition, under the same grinding parameters, the surface residual stress on two-dimensional ultrasonic vibration grinding is larger than that on ordinary grinding, and if other parameters unchanged, it is increased with the increase of wear particle granularity in the two grinding modes. It is produced by the reason that ductile regime of ceramic grinding become larger under ultrasonic grinding, so that material is still removed by plastic form at great depth. Plastic removal mode will produce greater surface extrusion stress, so with the increasing of grinding depth, the decreasing of residual stress under two-dimensional ultrasonic vibration grinding is less than that under the normal grinding. At the same time, the regular separating between wear particle and work piece improves the heat emission condition, which is also one of the reasons that the surface residual stress under two-dimensional ultrasonic grinding is larger than that under ordinary grinding.
A Strapdown Measurement of Vehicle Posture
Authors: Wu L.M. , Zhang L.K. , Li Y.F. , Xiao X.
Published: December 2010

Vehicle bodywork posture measurement has been a gordian technique in automotive．This paper presented a non-gyro bodywork posture measurement program．Using only one triaxial acceleration transducer with wheel speed encoders it provided a solution of calculating real-time bodywork posture．A lot of streamlining had been made within this program in order to assurance system for real-time performance．Concretely it gave an example of hardware implementation circuit through using LPC1758 as MCU and MMA7260 as triaxial accelerometer, as well as the noise filtering solusion for the circuit．This strapdown measurement has the advantages of high reliability，adaptability and good real-time performance，its precision meets the necessary accuracy requirement of normal application.
Research on Elliptic Vibration Dressing of Large-Grit Bronze-Bonded Diamond Grinding Wheel
Authors: Gao Guo Fu , Zhao Bo , Tong Jing Lin
Published: December 2010

The Large-grit bronze-bonded diamond grinding wheel was shaped employing a diamond dresser with elliptic ultrasonic vibration assistance, to solve problems such as high cost, low dressing speed and low accuracy. And the truing and conditioning performance of this new method was discussed for its effectiveness. Experimental results showed that the roundness error of elliptic vibration dressed diamond grinding wheel is less, and the bond tail was cut shorter and the chip capacity became larger than that of mechanical dressed one. The SEM observation showed for the present dressing method the material removal mechanism is ductile removal of bond material and micro breakup of gains and this method can perform truing of large-grit diamond grinding wheel as well as conditioning in one step.
Elastic Waves in Piezoelectric Spherical Curved Plates
Authors: Yu J.G. , Dong X.F.
Published: December 2010

Based on linear three-dimensional piezoelasticity, an orthogonal polynomial approach is used for determining the elastic wave characteristics of piezoelectric spherical curved plates. The displacement components and electric potential, expanded in a series of Legendre polynomials, are introduced into the governing equations along with position-dependent material constants so that the solution of the wave equation is reduced to an eigenvalue problem. Guided wave dispersion curves for PZT-4 spherical curved plates are calculated. Corresponding mechanical displacement and electric potential distributions are illustrated. The influence of the ratio of radius to thickness on the wave characteristics is discussed.
Study on the Edge Quality Control in Grinding Engineering Ceramics
Authors: Bian Ping Yan , Zhao Bo , Li Yu
Published: December 2010

In this paper, the edge quality of the nano-ZrO2 ceramics surface grinding was studied on experiments. Through the microscopic observation and measurement on the edge micro-step，and the white interference detection on the 3D surface profile of both sides of the edges, the edge quality traits are obtained，which lay a foundation for further study on the technology of the edge quality controlling and hard brittle material surface integrity evaluation.
Study on the Plastic Removal Mechanism of Nano-ZrO2 Ceramics by Ultrasonic Grinding
Authors: Xue Jin Xue , Zhao Bo , Gao Guo Fu
Published: December 2010

The brittleness, plasticity, super-plasticity and the removal mechanisms of critical fragmentation of the nano ZrO2 ceramics were investigated. The formula of critical ductile grinding depth of the common engineering ceramics was inapplicable to the nano-ZrO2 ceramics. A new formula of critical ductile grinding depth of the nano ceramics was established. The ultrasonic vibration grinding experiments showed that the critical ductile grinding depth of the ceramics was 15μm by conventional grinding, but the increment of the critical ductile grinding depth was 60 percent by ultrasonic grinding. The critical ductile grinding depth increased to 25μm. Analyzed by means of SEM, it was transgranular cracking during its cracking process. The nano-ZrO2 ceramics have high toughness so the critical ductile grinding depth increased. The shape, length, width and thickness of the grindings differed greatly from which obtained by conventional grinding.
Micro-Displacement Measurement with High Accuracy for Micro-Motion Stage Based on Computer Microvision
Authors: Fan Yan Bin , Lu Qing Hua , Zhang Xian Min
Published: December 2010

The micro-motion stages are critically important in modern manufacturing technology. In this paper, an integrated approach for measuring micro-displacement of micro-motion stage that incorporates micro-motion measurement algorithm into the computer microvision is proposed. At first, the basic principle of the computer microvision measurement is analyzed. Then, an algorithm for micro-motion measurement is proposed. Finally, the micro-displacement of the micro-motion stage is measured using the integrated approach. The maximal bias of this proposed combined approach reached 12.5 nm. Experimental results show that this method can measure micro-displacement with nanometer accuracy.
Sensor Optimal Placement for Bridge Structure Based on Single Parents Genetic Algorithm with Different Fitness Functions
Authors: Liu Han Bing , Wu Chun Li , Wang Jing
Published: December 2010

An investigation into sensor optimal placement for bridge structure based on Single Parents Genetic Algorithm with different fitness functions has been carried on. Five fitness functions are designed from several aspects on linear independence, orthogonality and energy of mode. The two-step method is proposed to determine the number of sensors firstly and then sensor position. An example of a large span arch bridge has proved the following facts: the Single Parents Genetic Algorithm is quite suitable to sensor optimal placement for bridge structure. Fitness functions designed by effective independence index and MAC and BHM combined index are more desirable than other evaluation indices. Two-step method used to determine the number of sensors and position is very effective.
Fatigue Reliability Analysis of the Stay Cables of Cable-Stayed Bridge under Combined Loads of Stochastic Traffic and Wind
Authors: Li Yan , Lv Da Gang , Sheng Hong Fei
Published: December 2010

The existent studies on cable stays fatigue for the serviced cable-stayed bridge generally only considered traffic or wind load action respectively. The long span cable-stayed bridges are very sensitive to wind load, so the fatigue estimation of cable stays considering traffic and wind load simultaneously is very important for the bridge safety. In the present research, taking an actual bridge as an example, based on linear cumulative damage theory, fatigue reliability of cable stays is analyzed under combined load of vehicles and wind. Firstly, based on the long-term traffic survey and wind speed data, traffic and wind load probability distribution models for the bridge are built respectively. Secondly, an intensive computational work is performed to obtain stress time history of the stay cables in the typical time block by running self-compiled Bridge-Vehicle-Wind interaction dynamic response analysis program. Thirdly, the stress result is updated in accordance with traffic growth and extreme wind speed changing in service period. The stress amplitude and frequency are attained by rain-flow cycle counting method. Finally, the fatigue damage limit state function of cable stays is proposed based on linear cumulative damage theory, and solved by Monte-Carlo method. The analysis result shows that the effect of buffeting wind load on the fatigue reliability of cable stays is significant, the influence degree increases generally in accordance with the order from short cable to long cable. The fatigue life of cable under designed safety probability reduces by the range from 2% to 63%, average 50% compared to only considering traffic load. So fatigue assessment of stay cables should take traffic and wind loads together into account. The proposed analysis framework offers a referenced fatigue assessment approach for conventional long span bridges.
Simplified Seismic Response Assessment Method and Parametric Study of Multi-Girder Skew Bridges
Authors: Huang Xin Yi , Chen Yan Jiang , Zhuo Wei Dong
Published: December 2010

A simplified grillage bridge model suitable for parametric study of skew bridge is presented, and the formulae for computing the seismic response of skew bridges are developed. Considering the existence of crossbeams and elastic bearings, the effects of stiffness eccentricity ratios, frequency ratios, the number of beams and skew angles are assessed using response spectrum analysis. The results show that the natural frequencies and mode shapes depend mainly on the stiffness eccentricity ratio and frequency ratios. The study also demonstrates that the seismic response of skew bridge is influenced quite noticeably by stiffness eccentricity ratio and frequency ratio. The maximum seismic response of skew bridge can be reduced by increasing stiffness eccentricity ratio and frequency ratio. Based on this study, a theory to evaluate the dynamic behavior and seismic response of skew bridges is presented and it can be conveniently applied in bridge seismic design.
The Effect of Vanadium and Chromium on the Precipitation of Carbide in Si-Mo Ferritic Ductile Cast Iron
Authors: Choe Kyeong Hwan , Lim Kyoung Mook , Lee Sang Mok , Lee Kyong Whoan
Published: December 2010

Carbide precipitation behavior in Si-Mo ferritic ductile cast iron was investigated as functions of vanadium and chromium contents. Vanadium addition promoted the precipitation of carbides both in ferrite grains and at its grain boundaries. Pearlite was found to form near the cell boundary next to the eutectic carbides in the as-cast chromium alloyed specimens, and was fully decomposed by an annealing heat treatment. Vanadium addition led to the formation of fine precipitates, prohibiting the ferrite growth, resulting in smaller ferrite grains. The precipitate phase at grain boundaries in vanadium alloyed specimens was identified as vanadium carbide (VC1-x) and the stoichiometry of the eutectic carbide was almost same as that in Si-Mo ferritic ductile cast iron except for a higher vanadium content. However, in the case of chromium alloyed specimen, the ratio of iron in the composition of eutectic carbide was higher than those of Si-Mo and Si-Mo-0.5V cast irons.
The Mechanism of Formation of Casting Skin in CG Iron and its Effect on Tensile Properties
Authors: Boonmee Sarum , Ştefănescu Doru Michael
Published: December 2010

Sand-cast compacted graphite (CG) cast iron typically presents a surface layer (the casting skin) whose microstructure is significantly different than that of the bulk material. It is generally believed that the casting skin is the result on interaction between the metal and the mold moisture and atmosphere. This reaction results in a decarburized or graphite-free layer. The thickness of this layer is a function of process variables (e.g. cooling rate, pouring temperature, binder, coating, sand fineness, and Mg and inoculation level). The paper presents a summary of recent findings on the negative effect of casting skin on the static properties of CG iron through the use of the skin quality factor for tensile strength, defined as the ratio between the as-cast and machined tensile strength. A mechanism of casting skin formation is proposed and supported with experimental and computational data.
Mechanism of Dissolved Sulfur Influence on the Transition from Graphite to Cementite Eutectic in Cast Iron
Authors: Fraś Edward , Górny M.
Published: December 2010

In this work an analytical solution is used to explain the mechanism of dissolved sulfur influence on the transition from graphite to cementite eutectic in cast iron. It is found that this transition can be related to (1) the nucleation potential of graphite (characterized by nucleation coefficients, Ns and b (2) the growth rate coefficient of graphite eutectic cell,  (3) the temperature range, Tsc = Ts - Tc (where Ts and Tc is the equilibrium temperature of the graphite eutectic and the formation temperature of the cementite eutectic respectively) and (4) the liquid volume fraction, fl after solidification of the pre-eutectic austenite. It has been shown that the main impact of dissolved sulfur on the transition from graphite to cementite eutectic consists in reducing the growth rate of graphite eutectic cell. Analytical equations were presented to describe the absolute chilling tendency, CT, and the chill, w of cast iron. Finally, it has been shown that as dissolved sulfur content in cast iron increases, the eutectic cell count, N, the maximum degree of undercooling at the onset of graphite eutectic solidification, ∆Tm, and the chilling tendency index, CT and chill, w increase as well.
Study of the Eutectoid Transformation in Grey Cast Irons and its Effect on Mechanical Properties
Authors: Sjögren Torsten , Svensson Henrik
Published: December 2010

In this experimental study, six pearlitic grey cast irons with different Cu and Cr content, different section thicknesses and different eutectoid cooling rates have been examined. The eutectoid cooling rate was approximated by casting simulation analysis. The purpose of the experiments was to study the effect of the matrix structure on the overall mechanical properties. An emphasis is put on the pearlite interlamellar spacing because this controls the resulting mechanical properties to a large extent. By keeping the graphite structure constant, the effect of the matrix structure was able to be studied. This was achieved by shake-out at temperatures above the eutectoid transformation range followed by subsequent cooling in air, mould or in a furnace. The pearlite interlamellar spacing ranged from 90 to 330 nm for the matrices studied. Comparing the strength of the fine structured and coarse structured materials, the tensile and yield strength was reduced by almost 50%. Regarding the elastic deformation, a weak increase in the tangent modulus with increasing alloying content was observed. It was also observed that lower cooling rate decreased the tangent modulus. The tangent modulus ranged between 70 and 110 GPa. Analysing the plastic deformation of the materials, in terms of strain hardening exponent, n, and strength coefficient, K, a strong dependence on the pearlite coarseness was observed. It was concluded that the effect of graphite particle length on tensile strength was negligible and the major improvement on the strength was due to refinement of the pearlite.
The Effect of Cooling Rate, Section Size and Alloying on Matrix Structure Formation in Pearlitic Grey Cast Iron
Authors: Svensson Henrik , Sjögren Torsten
Published: December 2010

The matrix structure formation of cast irons is strongly affected by the casting process where different alloying elements and cooling conditions are methods used to achieve the desired structure and performance of the material.
In the presented study, six pearlitic grey cast irons have been analysed regarding how the pearlitic structure formation might be controlled. Different amounts of copper and chromium were added, ranging from 0.07 to 1.11 wt% and 0.08 to 0.60 wt%, respectively. Three different section sizes (Ø20, Ø45 and Ø85 mm) and three different cooling conditions through the eutectoid transformation were used to control the matrix structure formation. The three different cooling conditions were achieved by shake-out at 950°C and cooling in air or furnace, or by keeping the casting in the mould.
The present paper focuses on the pearlite appearance, since it strongly affects the mechanical properties. The analysis shows that the refining effect of Cr is much stronger than that of Cu. Comparing the low alloyed base melt with the ones alloyed with Cu and Cr, it is seen that additions of 0.75 wt% Cu refines the pearlite by approximately 10%. Keeping this Cu level constant and adding Cr, it is observed that an addition of ~0.6 wt% refines the pearlite by another 20%. The most potent refining effect of Cr is achieved by additions up to 0.35 wt%. Keeping the Cr constant at 0.35% and changing the Cu content (0.35 to 1.10 wt%), almost no variation is observed in the overall interlamellar spacing. The eutectoid cooling rate most strongly affects the interlamellar spacing down to cooling rates of about -0.75 °C/s. At higher (i.e. lower value) cooling rates the interlamellar spacing is fairly constant. In addition to studying the interlamellar spacing, the graphite structure has also been analysed and evaluated concerning effects from the different casting variables.
Influence of Alloying Elements on the Bainitic Transformation of Ductile Iron
Authors: Karbakhsh Ravari B. , Nili Ahmadabadi M.
Published: December 2010

Alloying elements may be added to ductile iron to improve mechanical properties or prevent pearlitic transformation during austempering process. On the other hand, the segregation of alloying elements during solidification changes the kinetics of austempering process which in turn bainitic transformation would be function of local concentration of alloying elements. In this research, kinetics of the first stage of bainitic transformation in ductile iron has been studied by the means of comparing the bainitic transformation in steels with the same composition similar to the alloyed ductile iron matrix after austempering treatment. According to the results of dilatometry tests, the effect of Si and Mn in steel samples on the incubation time of bainitic transformation was obtained. Also, the influence of austempering temperature on "S-shape" curve has been investigated by means of dilatometry data.