bluuebunny/crossref_metadata_2025 huggingface dataset:
Design of a Two-Degree of Freedom Beating Machine
Authors: Zhang Shu Lian , Zeng Li Jiang
Published: March 2009

We propose a new beating machine based on a dual cam and lever mechanism to operate flapping and torsion motions of a dragonfly wing. The beating machine was designed according to the time dependent variation in flapping angle and in torsion angle of a free flight dragonfly. Our experiment results show that the variations in flapping angle and in torsion angle of a wing on beating machine agree well with those of a real free flight dragonfly wing, confirming that our beating machine is available for studying the beating performance. We then use the beating machine to study the aerodynamic force and inertia affecting on the wing by comparing the flapping angle and torsion angle under the normal and vacuum conditions.
A High Precision AFM for Nanometrology of Large Area Micro-Structured Surfaces
Authors: Aoki J. , Gao Wei , Kiyono S. , Ono T.
Published: March 2009

This paper presents a high precision AFM for nanometrology of large area micro-structured surfaces. A PZT with a stroke of 100 microns is used as the Z-directional actuator for the AFM cantilever. Two capacitance-type displacement probes are aligned at two sides of the PZT along the movement direction. The displacement as well as the tilt motion of the PZT can be accurately measured and compensated for based on the probe outputs. It was confirmed that the tilt motion of the PZT was approximately 32 arcseconds over the 100 micron stroke. The sample is moved by two linear stages for scanning in the X- and Y-directions over an area of 50 mm x 40 mm. The angular error motions of the stages that influence the AFM accuracy are measured by an autocollimator for compensation. A piezo-resistive cantilever, which can output the atomic force signal by itself, was employed instead of the conventional optical force sensing device for compactness of the AFM structure. A large area sinusoidal metrology surface has been successfully measured by the developed high-precision AFM.
Order Tracking Filtering for Rotating Machinery Diagnosis Based on Zero Phase Distortion Digital Filtering
Authors: Qin S.R. , Guo Y.
Published: March 2009

A new method for order tracking filtering of rotating machinery based on instantaneous frequency estimation and zero-phase distortion digital filtering is proposed. Compared with the traditional methods for order tracking filtering, the new method has a number of attractive features such as tacholess, no hardware-based tracking filter and no frequency shift to the original sampling data. The theorems and algorithms of the method are discussed. Filtering of overlapped data blocks, used to restrain the edge effect, which is caused by digital filtering, is introduced. An actual test example of run-up and coast down vibration of a motor is presented to demonstrate the validity of the method.
Use of Fiber Interferometer for AFM Cantilever Probe Displacement Control
Authors: Shie N.C. , Chen T.L. , Cheng Kai Yuan
Published: March 2009

This investigation presents a fibre-optic Fabry-Perot interferometer as a displacement sensor in an atomic force microsope (AFM). A simple model of light wave transmission between two fibres with the same core diameter is proposed to determine the theoretical equation of light intensity of interference fringes from the fibre-optic Fabry-Perot interferometer. By replacing an AFM cantilever with a movable reflective mirror, the variations of relative light intensity of the interference fringes with the spacing between the fibre and the mirror were recorded. The theoretical equation for the light intensity of interference fringes was close to those obtained experimentally. Finally, a fibre-optic Fabry-Perot interferometer was operated in an AFM to image a two-dimensional phase array with a pitch of 4 µm and a depth of 150 nm.
Room Temperature Creep and Its Influence on Fatigue Crack Growth in a 304 Stainless Steel
Authors: Zhao Jie , Mo Tao , Chen Weixing , Wang Fu Gang
Published: March 2009

The current paper investigated the phenomena of room temperature creep at the crack tip and its influence on fatigue crack growth behavior of a 304 stainless steel. From the experiments, a time-dependent deformation is obviously observed under various stress intensity factors. The deformation depends on stress intensity factor as well as load history. Both acceleration and retardation of fatigue crack growth are found after room temperature creep, which rest on load patterns. A distinct marking line was seen on the fracture surface following the holding period. It is proposed that the crack propagation mode changed after the hold time.
Evaluation of the Fretting Fatigue Behavior of Ti-6Al-4V Alloy
Authors: Kwon Jae Do , Bae Yong Tak , Choi Sung Jong , Chai Young Suck , Ishii Hitoshi
Published: March 2009

Fretting is a potential degradation mechanism of structural components and equipments exposed to various environments and loading conditions. It is well known that the fatigue life under fretting condition decreases approximately 50-70% compared with that under non-fretting fatigue condition. The specific gravity of titanium alloy is 4.5 which is lighter than steel, however, its specific strength, heat and corrosion resistance are superior to steel. Ti-6Al-4V alloy is a kind of a+b phase titanium alloy, and mechanical properties are changed by alloy elements, shapes and distributions of microstructures. In this study, three different kinds of specimens are prepared under different heat treatments in order to produce different microstructures. Through various kinds of mechanical tests, the following conclusions are observed: 1) The microstructures are observed as equiaxed, bimodal and lamellar microstructures respectively. 2) The elongation percentage is superior for the equiaxed microstructure, and the hardness and tensile strength are superior for the lamellar microstructure. 3) The plain fatigue limit of lamellar structure shows higher value than that of the equiaxed and bimodal structures. 4) The fretting fatigue limit considerably decreases compared with the plain fatigue limit
for all materials. 5) The fretting damage of contact surface increases with an increase of cyclic loading amplitude under the constant contact pressure.
Prediction of Elastic Properties in Discontinuous Composite Materials
Authors: Kim Hong Gun
Published: March 2009

The shortcoming of conventional SLT (Shear Lag Theory) is due to the neglect of stress transfer across the fiber ends, which results in the inaccurate stress variation for the fiber when the fiber aspect ratio is small in elastic loading. Thus a new model called NSLT (New Shear Lag Theory) is developed considering the stress concentration effects that exists in the matrix regions near fiber ends. In this paper the prediction of elastic composite modulus is presented to evaluate the stress
transfer mechanism using NSLT. A micromechanical FEA (Finite Element Analysis) model with axisymmetry is implemented to verify the results of fiber stresses and interfacial shear stresses. It is found that the proposed model gives a reasonable prediction compared with the results based on other models.
Impact Fracture Behavior in Alumina Ceramic Plates
Authors: Shin Hyung Seop , Oh Sang Yeob , Kim Moon Saeng , Daimaruya Masashi
Published: March 2009

In this study, a bar impact test of low velocity was carried out to gain an insight into the damage mechanism and sequence induced in alumina plates during quasi-static impact conditions. An experimental setup which could measure directly the impact force applied to the specimen and supply a compressive pre-stress to the specimen by utilizing an long bar impact was devised. During the bar impact testing, the influence of the pre-stress applied to the specimen along the impact direction on the fracture behavior was investigated. The measured impact force profiles explained
well the damage behavior induced in alumina plates. The application of higher pre-stress to the specimen led to less damage due to the suppression of radial cracks which was caused by the increase in the apparent stiffness of the plate. The observed results showed the following sequence in damage development: The development of cone crack at the impact region, the formation of radial cracks from the rear surface of plate depending on the plate thickness, and the occurrence of crushing or fragmentation within the cone envelope.
Simulation and Experimental Investigation of Impact Damage in Composite Shell
Authors: Zhao Gui Ping , Cho Chong Du , Kwon Oh Yang
Published: March 2009

In this paper, the energy absorption characteristics on extruded aluminum box-section strengthened with carbon-fiber-reinforced plastics (CFRP) laminates and/or foam material were investigated under impact loading. Impact tests using a pneumatic impact tester were conducted with the specimens in three-point bending flexure with consideration given to the side-door impact beams in vehicles. The absorbed energy to the specimen during the impact was determined from the loaddisplacement curve, which was obtained from the strain gauge attached to the impactor and the laser displacement transducer. From the results, it was found that the strengthening by externally bonding with CFRP laminates improved the impact-induced energy absorption. Also, the effect of the improvement was clearly seen in the case of the use of filling form material in the aluminum extrusion together with attaching CFRP laminates.
Impact Fracture Behavior of Zr-Based Bulk Metallic Glass Using Subsize Charpy Specimen
Authors: Shin Hyung Seop , Kim Ki Hyun , Jung Young Jin , Ko Dong Kyun
Published: March 2009

The impact fracture behavior of Zr-based bulk metallic glass was investigated by an
instrumented impact tester using subsize Charpy specimens. Influences of loading rate and notch shape on the fracture behavior of amorphous Zr-Al-Ni-Cu alloy were examined. As a result, the maximum load and absorbed fracture energy under impact loading were lower than those under quasi-static loading. A large part of the absorbed fracture energy in the Zr-based BMG was consumed in the process for crack initiation and not for crack propagation. In addition, fractographic characteristics of BMGs were investigated. Fractured surfaces under impact loading are smoother than those under quasi-static loading. The absorbed fracture energy appeared differently depending on the appearance of the shear bands developed. It can be found that the fracture energy and fracture toughness of Zr-based BMG are closely related with the extent of shear bands developed during fracture.
A New Position Sensor Using a Triangularly Shaped Piezoelectric PVDF Film
Authors: Lee Young Sup
Published: March 2009

This paper describes a novel tip position sensor for a cantilever beam made of a
triangularly shaped distributed piezoelectric PVDF (polyvinylidene fluoride) film. Due to the boundary condition of the cantilever beam and the spatial sensitivity function of the distributed PVDF sensor, the charge output of the PVDF sensor can be shown to be proportional to the tip position of the beam. Experimental result using the triangular PVDF sensor were compared with those using two commercially available position sensors: an inductive sensor and an accelerometer (after double integration). The resonance frequencies of the test beam, measured using the PVDF sensor, matched well with those measured with the two commercial sensors and the PVDF sensor also showed good coherence over wide frequency range, whereas the inductive sensor became poor above 300Hz. However, the measured response of the PVDF sensor showed a bit larger magnitude compared with the two commercial sensors at higher frequencies. The triangular PVDF sensor have a number of advantages over conventional position sensors and could be used as tip position sensors.
Effects of Temperature and Loading Rate on Fracture Toughness
Authors: Murakami Tetsuya , Toda Hiroyuki , Kobayashi Toshiro
Published: March 2009

It is known that fracture toughness value is affected by test temperature, specimen
thickness and loading rate. In the present study, specimen size and test temperature are varied widely with the obtained data then being analyzed using rate parameter. Additionally, the fracture toughness values are obtained using round bar-type specimen with a circular notch. This result is compared with the result of the CT specimens, and the advantage of using the round bar-type specimen with a circular notch to modify specimen size requirement is discussed. Sample material used is HT780 high tensile strength steel. The test specimens were 1T, 2T and 4T-CT that are described in ASTM E399. Notched round bar-type specimen with a diameter of 15mm and notch root radius of 0.25mm is also used. The test temperature is varied from a low temperature to room temperature, and loading rate is varied about the 1T-CT specimen and the notched round bar-type specimen between static and 1000mm/sec. The test temperature and the loading rate dependency of the fracture toughness values were arranged by the rate parameter. The fracture toughness value has decreased with the decrease in test temperature and with the increase in specimen thickness and loading rate. The fracture toughness value obtained from the notched round bar-type specimen indicated a value close to 2T-CT specimen. It is shown that valid fracture toughness value can be obtained with a small test specimen by the notched round bar-type specimen. The test temperature and the loading rate dependency of the fracture toughness values can be successfully arranged by the rate parameter that can express both
temperature and strain rate dependencies. Feasibility of using round bar-type specimen to obtain valid fracture toughness values with less specimen mass was demonstrated.
Numerical Study on the Fracture Evolution around Cavities in Rock
Authors: Wang Shan Yong , Au S.K. , Lam K.C. , Tang Chun An
Published: March 2009

By using numerical code RFPA2D (Rock Failure Process Analysis), the evolution of fracture around cavities subjected to uniaxial and polyaxial compression is examined through a series of model simulation. It is shown from the numerical results that the chain of events leading to the collapse of the cavity may involve all or some of the fractures designated as primary tensile, shear and remote fracture. Numerical simulated results reproduce the evolution of three types of fractures. Under the condition of no confining pressure, the tensile mode dominates with collapse coinciding with the sudden and explosive appearance of the secondary tensile fracture; at moderate higher confining pressure, the tensile mode is depressed, comparatively, the shear effect is strengthened. Nevertheless, tensile fractures especially in remote fractures stage still play a role; at higher pressure, the shear fracture dominates the remote fractures. In addition, the evolution and interact of fractures between multiple cavities is investigated, considering the stress redistribution and transference in compressive and tensile stress field.
Numerical Studies of the Influence of Heterogeneity on Rock Failure and Induced Earthquake Precursors
Authors: Jiao Ming Ruo , Tang Chun An , Sun W.F. , Wang Shu Hong
Published: March 2009

A series of numerical simulations were performed to investigate the effects of geometric and mechanical heterogeneity of pre-existing faults of rocks on their failure and induced earthquake precursors. The numerical results revealed that rock failures with the different heterogeneity produce the different earthquake precursors, which are in a good agreement with those of observations in nature.
Adjustment for Temperature and Deformation of Concrete Beams
Authors: Zhu Si Rong , Li Zhuo Qiu , Song Xian Hui
Published: March 2009

Cement structures such as bridges and dams often come into being distortion or exhibit excessive thermal stresses due to the sun radiation or freeze-thaw cycle. Therefore, temperature especially inner temperature difference or deformation of structures must be controlled or regulated sometimes in order to reduce thermal stresses or excessive deformation and to extend the life-span of structures. In this paper, the electro-thermal effects of smart cement are used to adjust temperature
difference or deformation of concrete beams without the need of peripheral non-structural materials. Concrete beams for temperature and deformation adjustment were fabricated, and some experimental results as well as the related conclusions about temperature difference and deformation were produced. Based on these results, experiments of temperature difference or deflection adjustment are further conducted successfully. The research results in this paper are the bases of temperature and deformation adjustment for mass concrete structures. A new path will be broken to adjust temperature or deformation easily for some structures.
Numerical Approach to Fracture Spacing in Two Layered Material
Authors: Chang Xu , Liu Junjie , Tang Chun An , Zhang Yong Bin , Zhang Juan Xia
Published: March 2009

Equally spaced opening-mode fractures always evolve in top layer attached to underlying layer. With a newly developed Material Failure Process Analysis code (MFPA2D), we have firstly investigated the stress distribution between two adjacent fractures as a function of the fracture-spacing-to-layer-thickness ratio using a two-layer model with a fractured top layer. The numerical results indicate the horizontal stress perpendicular to the fractures near the top surface changes from tensile to compressive when the fracture-spacing-to-layer-thickness ratio changes from greater than to less than a critical value. Then, the process from fracture initiation to fracture saturation is numerically modeled. The modeling of fracture process shows that the fractures initiate at the top surface and propagate to the interface between the two layers in the first stage. In the following stage, new fractures can infill between the earlier formed fractures and they always initiate
at the interface and propagate to the top surface. Numerical simulation clearly demonstrates that the stress state transition precludes further infilling of fractures and the fracture spacing reaches a constant state, i.e. the so-called fracture saturation.
Time-Dependent Cyclic Deformation and Failure Behavior and Its Damage Coupled Simulation for Solder Alloy 63Sn-37Pb
Authors: Yang Xianjie , Gao Qing
Published: March 2009

The tests of 63Sn-37Pb under cyclic strain and stress were conducted to investigate the material’s time-dependent behavior. A damage-coupled viscoplastic model and its failure criterion are proposed. The prediction of the proposed viscoplastic model implies that the model can describe the cyclic strain and cyclic stress ratcheting behavior, and the fatigue lives very well.
Bonding Parameters of Anisotropic Conductive Adhesive Film and Peeling Strength
Authors: Chen Xu , Zhang Jun , Jiao Chunlei , Liu Yan Min
Published: March 2009

The effects of different bonding parameters-temperature, pressure, curing time, bonding temperature ramp and post-processing on the adhesive strengths of Anisotropic Conductive Adhesive Film (ACF) interconnection were investigated. The test results showed the adhesive strength increased as the bonding temperature increase. The curing time had great influence on the adhesive strength of ACF joints. The adhesive strengths increased as the bonding pressure increasing, but decreased if the bonding pressure was over 0.25MPa. The effects of different Teflon thickness on the pressure header and post-processing on adhesive strengths performance of ACF joints were studied. It was shown that the 90o peeling strength became deteriorated as the Teflon thickness increase. Different post-processing conditions showed that the specimens kept in 120oC chamber for 30 minutes had the best performance of the ACF interconnection. The environmental experiments of the thermal cycling (-40 - 125oC) and the high temperature/humidity (85oC, 85%RH) aging were used to evaluate the reliability of the specimens with different bonding parameters. It was shown that the high temperature/humidity was the harshest condition to the ACF bonding. The optimum bonding parameters were determined to obtain better peeling strength.
Raman Piezo-Spectroscopic Investigation of Microscopic Residual Stresses in Ni-MLCC Devices
Authors: Sakashita Tatsuo , Nakamura Kentaro , Pezzotti Giuseppe , Chazono Hirokazu
Published: March 2009

Residual stresses in Ni-MLCC were investigated by Raman microprobe piezo-spectroscopic (PS) methods. The shape of the Raman spectrum of BaTiO3 in Ni-MLCC depended on the angle between the polarizing direction of the incident laser beam and the direction of the internal electrode. From a set of precise calibrations, we show that the orientation dependence arises from the interaction between internal stresses and the polycrystalline microstructure; by taking into account such an orientation dependence, we were able to establish a technique for the measurement of the distribution of residual stresses in Ni-MLCC.
Preparation and Characterization of PZT Thin Films on ITO/Glass Substrate by CSD
Authors: Ohno Tomoya , Fujimoto Masayuki , Suzuki Hisao
Published: March 2009

This paper describes the deposition of PZT thin films on soda-lime glass substrate with ITO bottom electrode by CSD (Chemical Solution Deposition). The transmittance of the obtained PZT thin film on ITO/glass substrate was about 60 % in the visible light region. The deposited transparent PZT thin film exhibited the ferroelectricity of Pr=36.3 μC/cm2 and Ec=71.3 kV/cm. In addition, the piezoelectric property of the resultant PZT thin film was relatively large and exhibited the measured effective d33 of 120 pC/N after the polarization.
Effect of Al-Doping into Zinc Oxide Films Prepared by Pulsed Laser Deposition Method with Various Oxidation Assists
Authors: Ryoken Haruki , Sakaguchi Isao , Ohgaki Takeshi , Adachi Yoshitaka , Takenaka Tadashi , Ohashi Naoki , Haneda Hajime
Published: March 2009

The defect structure of undoped and Al-doped ZnO films deposited by pulse laser deposition was investigated to understand the charge compensation mechanism in those films. Particularly, the effect of oxidation assist, i.e., O2 gas or oxygen radicals, on the defect structure of the resultant films was examined. The examination indicated that the defect structure of undoped ZnO was not affected by the oxidation assist, whereas the properties of Al-doped ZnO obviously varied with the method of oxidation assist. An analyses of oxygen diffusion in these films revealed that Al-doping enhanced formation of oxygen defects in Al-doped ZnO.
Study on Autogenous Deformation of Concrete Incorporating MgO as Expansive Agent
Authors: Liu Shu Hua , Fang Kun He
Published: March 2009

In order to establish a mathematic model of the autogenous deformation of concrete
incorporating MgO as expansive agent, we study the characteristics of it. Based on the results of testing researches and testing data, we get a mathematic model, which can clearly reveal the characteristics of autogenous deformation of concrete incorporating MgO as expansive agent. Autogenous deformation of concrete incorporating MgO as expansive agent is steady, the expansion is not infinite and there is no retrogress. Age mainly influences the basic equation of autogenous deformation. The content of MgO (or fly ash) and temperature will magnify (or reduce) the deformation.
Influence of Mixture Proportion and Curing Condition on Contribution of Fly Ash to Strength of Concrete
Authors: Wu F.-R. , Masuda Yoshihiro , Nakamura S. , Sato S.
Published: March 2009

To investigate the strength efficiency of fly ash in concrete, the contribution of fly ash to strength, k value was calculated with the equation: the strength difference between fly ash concrete and control concrete with no fly ash due to the different fly ash content divides by the strength difference between both control concrete with no fly ash due to the different cement content which equals to the former different fly ash content. The k values were organized with fly ash specific surface area, concrete curing condition and age of specimens. Based on a large number of data collected from several proceedings and journals published in Japan during 1981 to 2003, the influences of fly ash property, mixture proportion and curing condition on k value were investigated. Within the range of study the following observations were made: (1) When fly ash concrete kept in moist curing, the k value of fly ash with specific surface area from 250 to 500 m2/kg is averagely 0.5 to 0.6 or higher at an age of 91 days and later, whereas that of fly ash with specific surface area from 150 to 250 m2/kg is around 0.4 to 0.5, and with some cases contributing little to the strength. (2) In the range of a portland cement content of 250 to 450 kg/m3, the strength contribution tends to increase as the cement content increases. (3) The contributions of fly ash to strength at 91 and 364 days are 1.44 to 1.97 times as large as those at 28 days, respectively, by standard curing, but conversely decrease to 0.75 to 0.79 times those at 28 days by air curing.
Study on Properties of Cement Lime-Fly-Ash Soil
Authors: Bai Shun Guo , Hou Yong Feng
Published: March 2009

In recent years, with the extensive application of deep mixing method in reinforcing the soft clay, study on the basic properties of cement-soil has been conducted deeply. In order to improve economic benefits and social benefit of the deep mixing method, this paper focuses on strength and permeability of cement-soil incorporating both lime and fly ash through laboratory experiments. According to the experimental data, the properties of cement lime-fly-ash soil are compared with those of ordinary cement-soil. The results show that cement lime-fly-ash soil is better than ordinary cement-soil. And some valuable conclusions are drawn based on experimental data. Firstly, the fly ash and lime mixed can raise strength remarkably. Secondly, the fly ash and lime mixed can improve impermeability of cement-soil effectually, especially when cement mixing ratio is very low. Thirdly, adding only fly ash into cement-soil can have adverse effects on the impermeability of cement-soil. In addition, the equivalent cement mixing amount of cement lime-fly-ash soil is identified through experimental data. These conclusions are valuable to engineering design and construction.
Study on Distribution Feature of Fracture Toughness of Interface between Coarse Aggregate and Hardened Cement Mortar in Concrete
Authors: Xing Feng , Guo Xiang Yong , Leng Fa Guang , Fang Kun He , Zhang Ren Yu
Published: March 2009

Based on available test data and fracture criterion, by using probability fracture mechanics and mathematical statistical method, the distribution feature of fracture toughness, IC K , of interface between coarse aggregate and hardened cement mortar is analyzed, and a method of defining the least number of specimens for testing fracture toughness is provided. Weibull distribution or lognormal distribution is often used to analyze lifetime problem, so the two models are preferentially considered. The analysis shows that the fracture toughness conforms to lognormal distribution with degree of confidence g =0.9, relative deviation d =0.05 and the least number of specimens of 13. The study results can be used in the probability fracture analysis and construction quality control of interface between coarse aggregate and hardened cement mortar.
Pore Structure and Chloride Ion Transport Mechanisms in Concrete
Authors: Shi Cai Jun , Deng De Hua , Xie You Jun
Published: March 2009

Hardened cement paste and concrete are porous materials. Most engineering properties of hardened cement pastes and concrete, such as strength, shrinkage, permeability, etc., are influenced or controlled by their pore structure characteristics. The ingress of chloride ion into concrete can cause steel corrosion and damage of steel reinforced concrete structure. This paper reviews the pore
structure characteristics and transport mechanisms of chloride ion, such as hydrostatic advection, capillary suction, diffusion, thermal migration and electrical migration, in hardened cement pastes and concrete.
Properties and Microstructure of the New Phosphate Bonded Magnesia Cement
Authors: Ding Zhu , Li Zong Jin , Xing Feng
Published: March 2009

A novel phosphate bonded magnesia cement was developed recently, which sets quickly and develops high strength in the early ages. In the present research, the physical and mechanical properties, hydration products, and microstructure of the new cement were investigated. The new cement was mainly consists of dead burned magnesia, phosphate and fly ash. The results showed that it not only has high early strength, but also has high long-term strength. Interestingly, the strength of the cement increase with the content of fly ash, from 10 % - 40 % by weight. The
hardened cement paste has a dense microstructure, low open porosity and water sorptivity due to the low water to binder ratio. The reaction products after hydration of the cement includes struvite mineral and amorphous species.
Analysis of the Factors Affecting Crack Resistance of Dam Concrete
Authors: Chen Gai Xin , Jiang Fu-Tian
Published: March 2009

Crack prevention is still a main consideration in dam concrete technology. This paper summarizes the author's understanding about the factors affecting cracking-resistance of dam concrete, such as cold shrinkage, drying shrinkage, autogenous volume deformation and tensile strain capacity, etc. The tensile strain capacity is an important parameter in evaluating crack resistance of dam concrete. Reducing volume shrinkages and decreasing adiabatic rise of temperature are the effective measures for enhancing crack resistance of dam concrete, rather than raising the tensile strain capacity impractically especially by increasing cement content of concrete excessively.
Prediction of Crack Width of Chloride Contaminated Reinforced Concrete Structures
Authors: Zheng Jia Jin , Zhou Xin Zhu , Xu Shi Lang
Published: March 2009

Crack width is a significant parameter for assessing service life of reinforced concrete structures in chloride-laden environments. Corrosion-induced concrete cracking is a predominant causal factor influencing premature degradation of reinforced concrete structures, incurring considerable costs for repairs and inconvenience to the public due to interruptions. This gives rise to the need for accurate prediction of crack width in order to achieve cost-effectiveness in maintaining serviceability of concrete structures. It is in this regard that the present paper attempts to develop a quasi-brittle mechanical model to predict crack width of chloride contaminated concrete structures. Assuming that cracks be smeared uniformly in all directions and concrete be a quasi-brittle material, the displacement and stress in a concrete cover, before and after surface cracking, were derived
respectively in an analytical manner. Crack width, as a function of the cover depth, steel bar diameter, corrosion rate and time, was then determined. Finally, the analysis results were verified by comparing the solution with the experimental results. The effects of the cover depth, steel bar diameter and corrosion rate on the service life were discussed in detail.
Double-Layered Piezothermoelastic Hollow Cylinder under Thermal Loading
Authors: Chen Ying , Shi Zhifei
Published: March 2009

In the present paper, a long thick-walled piezothermoelastic hollow cylinder under a
symmetric thermal loading is studied. Based on the theory of elasticity, the mechanical and electrical as well as the thermal fields of the cylinder are obtained. Besides, the effects of both temperature change and the material difference between two layers on the mechanical responses and electric output of the cylinder are investigated in detail. For comparison, some discussions of numerical results are addressed at the end of this paper.
Mechanical Characteristics of Concrete Ballastless Track on the Track Traffic of Linear Induction Motor
Authors: Liang Gao , Yin Ke Ming , Hui Yin
Published: March 2009

In this paper, based on the elastic foundation beam theory, the influence rules of every combination of loads and operating modes for ballastless track of Linear Induction Motor (LIM) track traffic are studied. In addition, according to the construction character of prefabrication and cast-in-situ, the rules of how construction influences the mechanical characteristics of the ballastless track structure are given. On the basis of synthetical analysis of the distribution rules of ballastless track’s internal force, some appropriate suggestions for design and construction are put forward.
Analysis and Study of the Influence Factor on the Airflow of Ultra-Speed Grinding Wheel
Authors: Gong Ya Dong , Li H. , Cai Guang Qi
Published: March 2009

There’s a systemic exoteric analysis and experiment study about the distribution of Ultra-speed grinding airflow field and influence factors in this paper and lots of experiments has been done in different conditions by the method of PIV (particle image velocity). A great deal of data has been gathered and the method dealing with it by using the software such as FlowMap, Tecplot and Matlab has been brought forward. Experiment and measure have been done under different conditions and lots of experiment data and results have been obtained. Many kinds of general rules influenced by factors on Ultra-speed grinding airflow field by the analysis of the experiment results, for the purpose of supporting the base of study for the effective supply of cooling and lubrication liquid.
Nonlinear Stability and Bifurcation of Multi-D.O.F. Chatter System in Grinding Process
Authors: Han Qing Kai , Yu Tao , Zhang Zhi Wei , Wen Bang Chun
Published: March 2009

The nonlinear chatter in grinding machine system is discussed analytically in the paper. In higher speed grinding process, the self-excited chatter vibration is mostly induced by the change of grinding speed and grinding wheel shape. Here the grinding machine tool is viewed as a nonlinear multi-D.O.F. autonomous system, in which hysteretic factors of contact surfaces are also introduced. Firstly, the DOFs of the above system are reduced efficiently without changing its dynamic properties by utilizing the center manifold theorem and averaging method. Then, a low dimensional system and corresponding averaging equations are obtained. The stability and bifurcation of chatter system are discussed on the base of deduced averaging equations. It is proved that chatter occurs as a Hopf bifurcation emerging from the steady state at the origin of system. The theoretical analyses on the multi-DOF chattering system will lead to further understanding of the nonlinear mechanisms of higher speed grinding processes.
Study of Intelligent Prediction and Control of Workpiece Size in Traverse Grinding
Authors: Ding Ning , Wang Long Shan , Li Guang Fu , Wang J.Z. , Chen Xiao Wei
Published: March 2009

A size intelligent prediction control model during traverse grinding is constructed. The
model is composed of the neural network prediction model, the deformation optimal adaptive control system and fuzzy control model. Dynamic Elman network is used in the prediction model. The first and the second derivative of the actual amount removed from the workpiece are added into the network input, which can greatly improve the prediction accuracy. The flexible factor is introduced to the fuzzy control model, which can self-adapt and adjust the quantification factor and
scale factor in the fuzzy control. Simulation and experiment verify that the developed prediction control model is feasible and has high prediction and control precision.
Study on Fuzzy Reliability of Shaft Fixing Grinding Wheel in Internal Grinding
Authors: Ma Chun Xiang , Qu Z.H. , Wu Q.J. , Ruan Zhen , Xu Li Ming
Published: March 2009

The fuzzy allowable intervals of the deflection, the vibration frequency and the fatigue
strength of the shaft fixing grinding wheel are proposed in present paper based fuzzy set theory. According to fuzzy probability theory, the fuzzy reliability model of the rigidity, the fuzzy reliability model of the vibration and the fuzzy reliability model of the fatigue for the shaft fixing grinding wheel in internal grinding are given. The method is put into real example.
Model Establishment of Chip-Formation due to Shock under Ultra-High Speed Grinding
Authors: Zhao H.H. , Cai Guang Qi , Gao X.J.
Published: March 2009

The theory model of the indent experiment of the brittle material was established, its
specific energy was analyzed, and the calculation expression of the total specific energy for a single grain was given. Experiment process and results were given. Ultra-high speed grinding experiment was done, and its results were obtained. After the results were analyzed, the conclusions were gained that brittle materials could produce ductile-regime grinding under ultra-high speed shock. The model of mechanism of chip-formation due to shock in quasi-fluid phase on super-high speed
grinding was established, and the chip formation hypothesis for the chip formation mechanism on ultra high speed grinding was produced.
Study on Precise Rubbing Technology of HIPSN Ceramic Balls
Authors: Zhang Ke , Wu Yu Hou , Sun H. , Li S.H.
Published: March 2009

One of the most applications of HIPSN(Hot-Isocratic Pressed Silicon Nitride) ceramic ball bearings is applied to the high-speed spindle of numerical control machine tools and high-speed precise mechanics. However, it is very difficult to process the HIPSN ceramic ball bearing. In this paper, a new grinding process method, taper rubbing method, is applied to process the HIPSN ceramic ball. Mechanical analysis of taper rubbing method is given, and the influence of grinding parameters on the ceramic material excision rate, surface quality of ceramic ball and wear and tear ratio of diamond wheel is studied by taper rubbing method. The experimental results show that the HISPN ceramic balls of G3 and G5 are obtained with taper rubbing method by properly controlling the motion of HIPSN ceramic balls and selecting reasonable processing technological parameters.
A Basic Study on Precision in Electrochemical Abrasive Lapping of Plate
Authors: Xu Wen Ji , Pang Gui Bing , Fang Jian Cheng , Adayi Xieeryazidan , Wang Xu Yue
Published: March 2009

Taking plate as the example, this paper studies the effect of tool’s shape and movement on the electrochemical as well as mechanical lapping characteristics in Electrochemical Abrasive Lapping (ECAL). It is assumed that the removal size of electrochemical action at a random point is in direct proportion to the electrical amperage through this point and the removal size of the lapping action is in direct proportion to the relative frictional distance. Based on the assumption above,
electrochemical and mechanical lapping characteristics with different tools shape are studied theoretically. The results show that the diameter of the tool should be larger than the width of the workpiece when a discal tool is used and the inner diameter of the tool should be larger than the width of the workpiece when a ringed tool is used, on the other hand the ratio of the revolving radius of the tool to the diameter of the tool as larger as possible avails to improve the precision and so does the ratio of the angular velocity of the workpiece to the rotating angular velocity of the tool.
Experimental Study on Mechanism and Performance of Magnetic Abrasive Finishing
Authors: Zhang Shu Ren , Liu W.N.
Published: March 2009

Magnetic Abrasive Finishing (MAF) is relatively a new finishing technique that employs the magnetic force for finishing. In the paper, finishing mechanism of MAF is studied and four self-sharpening modes of abrasive particles are put forward. With the cylindrical magnetic abrasive apparatus designed and made by the author, a series of experiments on finishing the cylindrical surfaces of nonferromagnetic materials and ferromagnetic materials are carried out. The influence of technical parameters (finishing speed, feed speed, finishing time and so on) on finishing performance is analyzed. Choosing the optimized technical parameters, , the surface roughness of ferromagnetic materials changes from Ra 0.825µm to Ra 0.045µm after the 12-minute finishing experiment; the surface roughness of nonferromagnetic materials changes from Ra 0.434µm to Ra 0.096µm after the 20-minute finishing experiment.
Path Planning for Robot in Free-Form Surfaces Polishing
Authors: Zhan J.M. , Cao Zhi Qiang , Zhao Ji
Published: March 2009

Based on the direction-parallel path planning method, this paper constructs a kinematics model and an inverse kinematics model for a robotic ultrasonic EDM polishing system, and it presents the arithmetic on joints’ rotating displacements and joints’ rotating speeds. A set of computerized solutions to the two models is developed for the robotic polishing system under the conditions of keeping feed speed Vf and machining angle λ at some constants on free-form surfaces. In this way, it puts forward an easy and efficient way for robot in free-form surfaces polishing.
Kinematics of a 4-DOF Bipod Parallel Grinder
Authors: Zou Ping , Angeles J.
Published: March 2009

In this paper, a novel bipod parallel grinder with four controlled degrees of freedom is introduced. The moving platform of this 2-leg parallel grinder can always keep moving in horizontal plane by means of four-parallelogram mechanism (Π joints). The closed-form solutions of forward and inverse kinematics are derived.
The Constant Power Control of Hydraulic Grinding Saw
Authors: Song Jin Chun , Chen J.W. , Zhang Zhi Wei
Published: March 2009

Hydraulic grinding saw is a kind of important equipment broadly used in billet precise
cutting in metallurgical industry. In order to improve productivity significantly, control feeding speed reasonably, at the same time to compensate the variation of driving torque caused by the change of contacting area between grinding wheel and slab, thus to obtain the optimized match between the feed of the grinding wheel and the driving motor, the application of hydraulic servo system in the control of the feeding speed of grinding wheel is discussed in this thesis. This article introduces the principle of hydraulic grinding saw, brings out the project of constant power PID
control based on the relationship between driving torque and motor current. The transfer function of the hydraulic servo system, the optimized PID controller is also worked out. According to the result of simulation analysis, the controlling factors can be well obtained.
Ti Coating of Nanocrystalline Diamond by Atomic Layer Deposition
Authors: Zang Jian Bing , Lu Jing , Wang Yan Hui , Qi X.H. , Yuan Yun Gang
Published: March 2009

Nanocrystalline diamond compact possesses not only the advantageous performance of polycrystalline diamond but also the high strength and the high toughness of nano-ceramics. However, single-phase nanocrystalline diamond compact is very difficult to sinter because of a huge amount of oxygen-containing and nitrogen-containing functional groups absorbed on the surface of nanocrystalline diamond. In this paper, atomic layer deposition (ALD) method has been used to coat nanocrystalline diamond with titanium, which will promote the bonding of nanocrystalline diamond as the bond in polycrystalline diamond. In vacuum, the H2 and TiCl4 reactants were employed alternately in an ABAB… binary reaction sequence to achieve Ti layer, which reacted with diamond matrix and formed TiC in the coating, realizing strong chemical bonding between the coating and the diamond. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were utilized to study the structure and the morphology of the coating. The results confirmed the formation of titanium carbide at the depositing temperature 500°C. The darker spots and strips observed on nanocrystalline diamond particles by TEM were proved to be TiC and the nucleation and subsequent growth of TiC preferentially occurred in the defects as twin zones and dislocation areas on diamond surfaces.
The Research on New Grinding Head Used for Tool's Radius Offset of Spatial Conical Enveloping Surface Grinding
Authors: Zhang Yi Tong , Hu Zhuang Qi , Kang Ki Ju , Li Y.K.
Published: March 2009

A basic method and characteristic of tool’s radial offset for conical enveloping surface, its structure and working theory as well as the most advanced planetary grinding head used in tool’s radial offset in the world are introduced. In order to improve the dynamic property of grinding head and method used in tool’s offset in existence, a new type of grinding head that can realize tool’s radial offset to big tool’s radial error was developed. It has the advantages of simpler
structure, easier machining, lower cost, continuous and stable machining, and high efficiency, and is a new method of complex tool’s position offset.
A Model for Estimation of Convection Heat Transfer Coefficient of Fluid through the Grinding Zone
Authors: Lin Bin , Wang Z.F. , Morgan Michael N. , Liu Chao
Published: March 2009

The grinding fluid is typically used to provide functions such as lubrication and cooling in order to reduce surface grinding temperatures effectively in order to achieve better work-piece surface integrity and higher wheel life. This paper investigates the convection heat transfer coefficient of fluid based on the fluid dynamic and thermal modelling within the grinding zone under different grinding condition. This work makes it possible to determine a suitable value of the useful flowrate fluid through the grinding contact arc under optimization of the wheel speed, work speed and jet velocity of nozzle. Its simplicity and accuracy allow application to a wide range of grinding situations from shallow to high efficiency deep grinding.
A Study on Surface Generation of Metal-Bonded Diamond Grinding Wheel Dressed by Electro-Contact Discharge
Authors: Xie Jin , Tang Yong , Tamaki Junichi
Published: March 2009

This paper conducted Electro-Contact Discharge (ECD) dressing experiment for #600 diamond grinding wheel to understand how fine diamond grits protrude from metal-bonded wheel surface. The SEM observation, EDS analysis, image processing and 3D grit modeling on wheel surface were carried out to investigate grit protrusion characteristics. Then ECD dressing and mechanical dressing experiments were carried out to identify the effect of grit protrusion feature on
grinding performance. It is confirmed that the dressed wheel surface topography is sensitive to open circuit voltage Ei, discharge polarity and electrode composition. Meanwhile, ECD dressing with Ei=15V and straight polarity can produce superior protrusion topography without the damage of diamond crystal faces and the bond tail behind protrusive grit. It can obtain better ground surface of hard-brittle material than mechanical dressing with the bond tail.
Optimization of Dissimilar Friction Welding and Creep Rupture Tests for Nuclear Reactor Component Materials
Authors: Kong Yu Sik , Kwon Sang Woo , Kim Seon Jin
Published: March 2009

An experimental work of dissimilar friction welding was conducted using 15 mm diameter solid bar in copper alloy (Cu-1Cr-0.5Zr) to stainless steel (STS316L) for being used as fusion reactor component materials, not only to optimize the friction welding parameters, but also to investigate the elevated temperature tensile strength and creep rupture properties for the friction welded joints under the optimal welding conditions. The main friction welding parameters were selected to endure good quality welds on the basis of visual examination, tensile tests, Vickers hardness survey of the bond area and HAZ. For friction weld joining of copper alloy to stainless steel bars, the total upset increases lineally as increasing heating time. Optimal welding conditions were selected as follows: Rotational speed 2000rpm, friction pressure 80MPa, upsetting pressure 140MPa, heating time 2 second, upsetting time 5 second and total upset 13mm. The weld interface of dissimilar friction welded steel bars was mixed strongly. And also the creep properties and creep life prediction by Larson-Miller parameter method were presented at the elevated temperatures of 300, 400 and 500oC.