bluuebunny/crossref_metadata_2025 huggingface dataset:
Boundary Element Analysis of an Interface Crack in a Bonded Viscoelastic Thin Film
Authors: Lee Sang Soon , Yi Mi Hie
Published: March 2009

Interfacial stress singularities induced in a laminate model consisting of the viscoelastic thin film and the elastic substrate have been investigated using the time-domain boundary element method. First, the interfacial singular stresses between the viscoelastic thin film and the elastic substrate subjected to a uniform moisture ingression have been investigated near the free surface, but without any edge crack. The thin film is assumed to be a linear viscoelastic material and moisture
effects are assumed to be analogous to thermal effects. Then, the overall stress intensity factor for the case of a small interfacial edge crack of length a has been computed. The numerical procedure does not permit calculation of the limiting case for which the edge crack length vanishes.
Finite Element Analysis of Fracture Process of Weld Specimen
Authors: Yang Sung Yong , Goo Byeong Choon
Published: March 2009

Mechanical behavior and fracture process of weld specimens were analyzed by finite element method. Three-dimensional butt-weld specimen was modeled by two-dimensional approaches. Welding residual stress in the models was obtained by carrying out thermo-mechanical calculation. To take into account straight boundary lines of real weld specimen, the finite element model was constructed by using an iterative method. Cohesive zone method was applied to analyze fatigue behavior of the models.
Shot Peening and Fatigue Crack Growth in 7075-T7351 Aluminum
Authors: Honda Takashi , Ramulu Mamidala , Kobayshi Albert S.
Published: March 2009

Thirty three SENB and nine TPB specimens, which were machined from an 8.1mm thick 7075-T7351 aluminum stock plate, were fatigued in the as-received or shot peened conditions. The SENB specimens were then fractured by overload and were recorded. The crack growth rate of the tunneling crack profiles were measured by fractography at various life cycles. SN curves of the as received and shot peened TPB specimens were also constructed. Peened surface roughness, subsurface microstructure and micro-hardness profiles were examined. X-ray diffraction technique was used to measure the residual stresses in selected shot peened SENB and TPB specimens. The fatigue life under a severe shot peening intensity (Almen scale 0.016A) of the SENB specimens was slightly larger than that of the as received SENB specimens at low stress ratio of R = 0.1 but the difference was found to be smaller at R = 0.8. The SN curves of the as received and severely shot peened TPB specimens were nearly identical. Grain distortion due to peening was observed to a depth of 410µm and was correlated with the measured residual compressive stresses. The compressive residual stress had little effect on the crack growth rates in shot peened SENB and TPB specimens.
Basic Concept on Structural Design Criteria for Zirconia Ceramics Applying to Nuclear Components
Authors: Shibata Taiju , Sumita Junya , Baba Sinichi , Yamaji Masatoshi , Ishihara Masahiro , Iyoku Tatsuo , Tsuji Nobumasa
Published: March 2009

As an advanced in-core material in high temperature gas-cooled reactors (HTGRs), superplastic ceramics is attractive due to the possibility of the plastic working. For the application to the nuclear fields, the basic concept of design criteria was studied for typical superplastic ceramics, tetragonal zirconia polycrystals containing 3mol% yttria (3Y-TZP). The experimental results on 3Y-TZP showed that it is possible to apply the Weibull weakest-link theory to decide the stress limits
in the criteria. The Weibull parameter m was evaluated as 9.5 for the bending and as 26.5 for the compressive. The applicability of the Weibull theory was also verified by the bending test results with different span. Based on the graphite structural design guidelines for the High Temperature Engineering Test Reactor (HTTR), the design stress limits for 3Y-TZP was proposed. It was shown that the proposed stress limits have appropriate safety margin and thought to be effective to evaluate
the integrity of in-core structure made of 3Y-TZP.
Fatigue Life Prediction of Ship Welded Materials
Authors: Han Min Koo , Ramulu Mamidala
Published: March 2009

Fatigue crack propagation life of weld toe crack through residual stress field was estimated using Elber's crack closure concept. Propagation of weld toe crack is heavily influenced by residual stresses caused by the welding process, so it is essential to take into account the effect of residual stresses on the propagation life of a weld toe crack. Fatigue cracks at transverse and longitudinal weld toe was studied, these two cases represent the typical weld joints in ship structures. Numerical and experimental studies are performed for both cases. Residual stresses near the welding area were estimated through a nonlinear thermo-elasto-plastic finite element method and the residual stress intensity factor with Glinka's weight function method. Effective stress intensity factor was calculated using the Newman-Forman-de Koning-Henriksen equation, which is based on the Dugdale strip yield model in estimating the crack closure level, U, at different stress ratios. Calculated crack propagation life coincided well with experimental results.
Ductile to Brittle Transition of Pure Al Sheet Constrained by Parallel Bi-Interface with High Strength Al Alloy
Authors: Sun J. , Han L.H. , Li L.
Published: March 2009

The ductile to brittle transition (DBT) phenomena in pure metal was reviewed briefly with the emphasis on effects of stress triaxiality and confined dislocation slip. Experimental and numerical methods were used to investigate the DBT of inter pure Al sheet sandwiched by 2024 Al alloy through explosive cladding. The experimental results clearly showed that this transition has taken place with its decreasing thickness, h , characterized by decreasing fracture toughness and local cleavage
patterns where the {100} facets are dominant. Finite element calculations show that it is the constraint of elastic fraction of substrates on the yield zone in inter Al layer that results in an increasingly high triaxial tensile stress, which makes the material become brittle. The banded-grain boundaries have a similar role to strong interface in preventing dislocations slip.
Fatigue Analysis of Nuclear Welded Structures Based on Structural Stress and Elasto-Plastic Fracture Mechanics Approach
Authors: Kim Jong Sung , Jin Tae Eun
Published: March 2009

In the paper, the validity of the modified mesh-insensitive SS (structural stress) procedure to apply to the welded joints with local thickness variation is identified via the comparison of SCFs (stress concentration factors) calculated for various FE (finite element) models. FCI (fatigue crac kinitiation) cycles are determined by using the SS/EPFM (elasto-plastic fracture mechanics) approach and the various fatigue crack growth models. Fatigue test is performed to identify the validity of the fatigue analysis results. Finally, as a result of comparison among test and various analysis results, it is found that the SS/FM (fracture mechanics) approach agrees well with the fatigue test results over all cycle regions and the SS/EPFM approach is more reliable than the SS/LEFM (linear elastic fracture
mechanics) approach.
Influence of Specimen Configuration and TIG Welding on Fracture Toughness of RAFs (JLF-1)
Authors: Yoon Han Ki , Kim Dong Hyun , Park Won Jo , Kohyama Akira
Published: March 2009

In order to apply a reduced activation ferritic (JLF-1) steel to the blanket/first-wall
structure of a fusion reactor, its fracture toughness is very important for the strict estimation of material life. Fracture toughness testing of irradiated materials requires the use of miniaturised specimens and evaluation of TIG welding (tungsten inert gas arc welding) weldment properties is an important issue because necessary for production of nuclear fusion reactors. In this study, the fracture toughness tests were carried out according to the ASTM E1820-99. It was performed on various sizes (ligament and thickness) and various side-grooves of specimens and the TIG welding joint of JLF-1. The test results showed the standard specimen with side-groove of 40% represented valid fracture toughness. Fracture resistance curve (R-curve) increased with increasing specimen ligament and decreased with increasing specimen thickness. However, the R-curve of half size specimen was similar to that of the standard (1inch thickness) specimen. The fracture toughness test results of the TIG welded specimen showed a slight increase in the TIG welded specimen compared with JLF-1 base metal specimen.
Mechanical and Electrical Properties of Sn-3.5Ag Solder/Cu BGA Packages during Multiple Reflows
Authors: Koo Ja Myeong , Lee Young Ho , Kim Sun Kyu , Jeong Myung Yong , Jung Seung Boo
Published: March 2009

The mechanical and electrical properties of the Sn-3.5Ag solder/Cu BGA packages were investigated as a function of number of reflows. A continuous scallop-shaped Cu6Sn5 intermetallic compound (IMC) layer was formed at the solder/Cu interface upon 1 reflow process. After 3 reflows, very thin layer of Cu3Sn IMC was observed at the Cu6Sn5/Cu interface. As the number of reflows increased, the thickness of these IMCs increased with a cube root of reflow time. Shear force slightly increased up to 4 reflows and then gradually decreased with increasing the number of reflows. The maximum shear force was 11.7N when the thickness of the IMC layers was 3.7㎛. The fracture surfaces of all the specimens showed ductile failure characteristics up to 4 reflows, and then the fraction of the brittle IMC fracture increased with the number of reflows. The electrical resistance of the BGA packages increased with the number of reflows.
Investigations of Interfacial Reaction and Shear Strength between Pb-Free Flip Chip Solder and Electroplated Cu UBM
Authors: Kim Dae Gon , Jang Hyung Sun , Kim Jong Woong , Jung Seung Boo
Published: March 2009

In the present work, we investigated the interfacial reactions and shear properties between Sn-3.0Ag-0.5Cu flip chip solder bump and Cu UBM after multiple reflows. The quantitative analyses of the intermetallic compound layer thickness as a function of the number of reflows were performed. After six reflows, the reaction product could be distinguished by two intermetallic compounds: Cu3Sn adjacent to the substrate and Cu6Sn5 which was the dominant phase. The thickness of total
intermetallic compound layers increased with the number of reflows. The shear strength value did not significantly change as a function of the number of reflows. Nearly all of the test specimens showed ductile failure mode, and this could be well explained with the results of FEM analyses.
Reliability Characterization of Organic Solderability Preservatives (OSP) of IC Packages by Drop and Cyclic Bend Test
Authors: Kim Seung Mo , Shon Eun Sook , Ka Yoon Hyun , Kim Yong Joon , Kim Jin Young , Kim Jae Dong
Published: March 2009

Cyclic bend test and drop test were carried out as a second level reliability test method in order to characterize the joint performance between electronic components and board. Two types of package substrates were used for the test. The one was NiAu plated, and the other one was organic solderability preservatives (OSP) finished. Drop test was done in accordance with JEDEC standard test method [1]. Drop impact and duration time was 1,500G and 0.5ms, respectively. Cyclic bend test was performed with Amkor internal specification because there is no international standard for the test. The Amkor internal specification was edited based on the IPC/JEDEC specification [2]. Board deflection and cyclic frequency was 3mm and 1Hz, respectively. NiAu substrate showed better mean life performance about by 30% in cyclic bend test. OSP substrate showed the same or better failure rate performance in drop test. Typical solder joint failures and intermetalic crack were found by failure analysis.
Optimal Structural Design of Multi Chip Package to Reduce the Failure in Substrate
Authors: Shin Dong Kil , Kim Seung Woo , Kim Shin , Lee Seok Won , Choi Hee Kook
Published: March 2009

In this study, epoxy molded multi chip package was investigated and a highly reliable
structure against failure of copper trace on PCB substrate was proposed. Function failure caused by the pattern crack during component level thermal cycle test was considered. In-plane and out-of-plane movements of package during thermal loading were measured by moiré interferometry and shadow moiré. Measured data were compared with numerical analysis results. Two dimensional and three dimensional numerical analysis were performed considering visco-elastic material properties. Tensile stress in the core layer was analyzed quantitatively and qualitatively. Analysis showed that the reliability of pattern crack could be improved by decreasing the chip thickness and increasing the core thickness, and that the material property of die adhesive was important.
Effects of Hydrogen Gas Environment on Non-Propagation Phenomena of a Type 304 Austenitic Stainless Steel
Authors: Aoki Y. , Matsuyama T. , Oda Yasuji , Higashida Kenji , Noguchi Hiroshi
Published: March 2009

In order to investigate the hydrogen gas effect on non-propagation phenomena of a type 304 austenitic stainless steel, fatigue tests with in-situ observation using a Scanning Laser Microscope were performed in air, in 0.18MPa hydrogen gas and in 0.18MPa nitrogen gas. A nonpropagating crack was observed during the fatigue test in air. At almost the same stress level of non-propagating in air, non-propagating cracks were also observed in fatigue tests in hydrogen and in nitrogen. Stress level of the non-propagation is not sufficiently different in the three environments. However, the process up to non-propagation differs from each other, for example, the crack path and debris.
Evaluation of Cracking Behavior of SPV50Q High Strength Steel Weldment in Wet H2S Containing Environment
Authors: Gong Jian Ming , Tang Jian Qun , Zhang Xian Chen , Tu Shan Tung
Published: March 2009

JIS-SPV50Q high strength steel is often employed in construction of liquid petroleum gas (LPG) spherical tanks due to its high strength and good ductility. In general, post weld heat treatment is not performed after welding of SPV50Q high strength steel and welding residual stress will be retained in weldment. Service experience and inspection indicate that higher H2S concentration and welding residual stress result in the environmental failure, such as blistering or hydrogen induced cracking (HIC), sulfide stress corrosion cracking (SSCC) and stress oriented hydrogen induced cracking (SOHIC). In the present paper, the cracking behavior of SPV50Q high strength steel weldment by manual electric arc welding has been investigated in various saturate solutions with different concentrations of H2S. The results of slow strain rate testing, performed at a strain of 1×10-6s-1, reveal the presence of SSCC and HIC in the base metal adjacent to HAZ. The ffects of the different temperatures of post weld heat treatment on cracking are discussed. The suitable post weld heat treatment could increase the resistance of SPV50Q weldment on SSCC or HIC and does not decrease the mechanical properties of SPV50Q weldment.
Study on Mechanical Behaviors of 16MnR Steel after Long Term Used as Liquefied Petroleum Gas Vessel
Authors: Chen Bing Bing , Sun Wei Ming , Gao Zeng Liang , Fang De Ming
Published: March 2009

16MnR steel is one of C-Mn steels widely used for pressure vessels in China. Mechanical behaviors of 16MnR steel used as liquefied petroleum gas vessel for about 100,000hr have been investigated in this paper. The macrostructure, fracture toughness, fatigue-crack growth rate, and low-cycle fatigue properties of the samples have been studied in detail. Compared the results with that of GB6654-86 (one of Chinese national material standards) and other test data of 16MnR steel, it
indicates that the mechanical properties of the long-term used 16MnR steel have not been degraded and aged.
Stress Corrosion Crack Tests of 16MnR Low Alloy Steel in Anhydrous Ammonia Environment
Authors: Lu Zhiming , Chen Bing Bing , Gao Zeng Liang , Fang De Ming
Published: March 2009

Anhydrous ammonia is one of the medium where the steel is easy to suffer stress corrosion cracking. Many stress corrosion crack accidents of ammonia storage tanks have been reported all over the world for recent years. 16MnR low alloy steel with good composite mechanical properties is the most common used pressure vessel steel in China, it has better anticorrosion properties than the low alloy high strength steel, especially in anhydrous ammonia environments. Many stress corrosion crack researches have been done for 16MnR steel in wet hydrogen sulfide service for last decades, but less has been done in anhydrous ammonia environments. Stress corrosion tests with eight constant strain pre-cracked specimen were carried out in this work. The pre-cracked specimen were loaded with
loading bolts and put into the special ammonia storage tank for tests, they were taken out from the tank periodically to measure crack length. The stress corrosion crack growth rate and the threshold stress intensity factors KISCC of 16MnR steel in anhydrous ammonia environments were measured. Based on test results, the effects of environmental factors and steel strength on stress corrosion cracking of 16MnR steel in anhydrous ammonia service were analyzed. It could be concluded that specimen cracks of the 16MnR steel in anhydrous ammonia environments almost do not grow, threshold stress intensity factors KISCC are higher than 90MPa m .
Estimation Method of SCC Initiation Site Based on Electrochemical Transients
Authors: Watanabe Yutaka , Sato Keisuke , Uchimoto Tetsuya , Takagi Toshiyuki
Published: March 2009

Although electrochemical transients can provide very sensitive indication about the onset of localized corrosion, including initiation of stress corrosion cracking (SCC), information on location of the initiation site is not available. In the present study, we proposed an estimation method of location and magnitude of SCC initiation events, where electrochemical transients associated with local anodic events are measured by multiple reference electrodes and location of the initiation sites are estimated based on relative magnitude of the electrochemical transients simultaneously measured at multiple locations.
Dielectric Measurement of BaTiO3 Powder and Its Statistical Analysis
Authors: Sekine Takashi , Hoshina Takuya , Nam Song Min , Yasuno Hiroaki , Kakemoto Hirofumi , Wada Satoshi , Tsurumi Takaaki
Published: March 2009

Dielectric permittivity of BaTiO3 powders was determined by measuring permittivity of slurries prepared from BaTiO3 powder and propylene carbonate as dispersion medium followed by analyzing with a finite element methods (FEM). The permittivity of powders depended on their characters such as tetragonality (c/a ratio), density, particle size and specific surface area. In order to extract the effect of each character, a statistical analysis was carried out to represent the permittivity of powders with an empirical equation where the c/a ratio, density and particle size were used as parameters. A fairly good agreement between observed data and those estimated from the relation was obtained and the contribution of each character to the permittivity could be determined.
Electrochemical Properties of Nanoporous TiO2 Films
Authors: Miki Takeshi , Nishizawa Kaori , Suzuki Kazuyuki , Kato Kazumi
Published: March 2009

The precursor solutions containing TiO2 sol for nanoporous films were prepared by hydrolyzing titanium(IV) isopropoxide and adding trehalose dihydrate. The porous and thick TiO2 film was prepared by dip-coating technique on glass substrate and heating at 500 °C. The film was composed of nano sized particles (10-20 nm) and pores (7 nm). The specific surface area of the film was 163 m2/g. The film had humidity-sensitive electrical resistance at room temperature.
Preparation of Lithium Ion Conductive Li4.2Al0.2Si0.8O4 Thin Films Using Sol-Gel Process
Authors: Isshiki Yasuhiro , Dokko Kaoru , Hamagami Jun Ichi , Takei Takashi , Kanamura Kiyoshi
Published: March 2009

Thin films of lithium ion conductive ceramic Li4+xAlxSi1-xO4 were fabricated on Au substrate using sol-gel process. The sol of Li-Al-Si-O was spread on Au substrate using a spin coater, and it was gelated at room temperature. The gel was calcinated at 400 °C and heat-treated at high temperatures between 500 °C and 800 °C in air. The addition of poly(vinylpyrrolidone) (PVP) was effective in stabilizing the sol. Furthermore, the morphology of the obtained thin film was changed by the PVP additive. Li4+xAlxSi1-xO4 thin film prepared at 800 °C exhibited a Li+ ion conductivity of 10-8 S cm-1 at room temperature.
Study on Pozzolanic Activity of Mineral Admixtures in Forms of Li-Salt Industrial Residue and Fly Ash
Authors: Xia Chun , Wang Bing Jie , Song Qi Lin
Published: March 2009

Tests have been done to study the compound mineral admixtures of lithium-salt
industrial residue (LSR) and fly ash. The results indicate that the addition of LSR plays a significant influence on both pozzolanic activity and strength of concrete at ages of 7d, 28 d, and 60 d respectively. An optimum dosage of LSR is identified in the compound admixtures. It is of certain practical value to the study and application of the high compound admixtures content and high fly ash content concrete.
Study of Controlling ASR with Fly Ash
Authors: Wu Ding Yan , Li Zeng , Fang Kun He , Liu Shu Hua
Published: March 2009

This study has investigated the controlling ASR with high quality I class fly ash. The
results show that the content of fly ash is more important than the quality of fly ash for the effect on preventing ASR. The solubility of alkali in fly ash has been studied in various alkali concentration solutions. The mechanism of a low content of fly ash accelerating swell of concrete but a high content of fly ash controlling swell is discussed for controlling ASR with fly ash contained high alkali content.
Integrated Utilization of Ultra-Fine Fly Ash—Fluoro Gypsum for Highway Repair
Authors: Gao Ying Li , Zhou Shi Qiong , Yin Jian
Published: March 2009

To solve existing problem of cement concrete pavement destruction in China, the
cement-based highway repair materials with Ultra-fine Fly Ash (UFA)—Fluoro gypsum as the main ingredients, which are all industrial wastes, are researched by employing UFA for both water-reducing and strength-enhancing. The mutual motivating effect of Fluoro gypsum and UFA during cement hydration is also explored. According to data analysis of experimental results, UFA-Fluoro gypsum high-performance highway repair materials are optimized, and then applied to production of highway rapid repair concrete where mechanical properties and partial long-term properties of the concrete are measured. The results indicate that the 1-day concrete strength closes to or reaches 30MPa, which meets the requirements of highway rapid repair project. The long time performance of concrete is also favorable. Finally, its hydration mechanism is analyzed preliminarily.
Development and Subjects of Recycled Aggregate Concrete in Japan
Authors: Kasai Yoshio
Published: March 2009

The quality of RCA is influenced by the processing method and quality of original concrete. The general character of RCA, RCA and TR A 0006-2000(concrete using recycled aggregate) are introduced. The execution of RAC work, examples of real constructions with RAC, recycling of concrete powder originated from production of RAC and barriers of using RAC are discussed.
Penetration Behavior of Chloride Ions into Concrete in Coastal Areas
Authors: Masuda Yoshihiro , Wu F.-R. , Nakamura S. , Sato S.
Published: March 2009

Exposure test on chloride ion penetration behavior into Concrete in coastal area was
implemented. The distances between concrete specimens and coast were changed in the range from 50 to 150 meters, and water-cement ratios (W/C) were 45, 55, 60 and 65 %. The total chloride ion content at each different depth from surface of concrete specimen was measured at the age of 1, 2, 3, 5, 7, 8 and 10 years. In this paper, apparent diffusion coefficient (D) and chloride ion content on surface of concrete (C0) were calculated by inverse analyses from the measured total chloride ion content, and the chloride ion penetration behavior was simulated using the calculated D and C0. As a result, the chloride ion penetrated in concrete with a W/C of 60 % at a point 50 m from the sea for 10 years was estimated approximately 0.2 kg/m3.
Stress Analysis and Experimental Verification on Corroded Prestressed Concrete Beam
Authors: Zhu Er Yu , Liu Chun , He Li , Zhang Hong Wei , Xie Nan
Published: March 2009

The paper presents a finite element analysis and static-load experimental verification on stress performance of corroded prestressed concrete bridge at Bai-Kong bridge of Shijiazhuang City on Beijing-Guangzhou Railway. At first, calculation of the actual bridge is simplified, mesh of the finite element of the bridge model is introduced, including the mesh of the finite element of undamaged bridge and the corroded bridge. For the situation above-mentioned, the finite element calculation result of the actual bridge is also presented in this paper. The graphic of the static load on the actual bridge and the testing spots distribution are described in this paper. Finally, the contrast between the static test result and the finite element calculation result is presented in this paper too.
Grinding Wheel Loading Features Extracted by Image Processing
Authors: Feng Z. , Chen Xun
Published: March 2009

The paper presents a method that identifies and extracts features of chips on loading grinding wheel using image processing technology. The Sobel operator is adopted to detect chips edge. The segmenting threshold was obtained by applying Otsu's method. Image dilation connects the discontinuous segments to yield continuous and close shapes of chips. Erosion removes the noise from the image. The different optical characters between metal chips and abrasive grains are analysed. The ratios of chips are calculated and displayed to monitor the wheel surface working status. The toolbox of the MATLAB is used for image processing.
Application of Hilbert-Huang Transform to Predict Grinding Surface Quality On-Line
Authors: Wu Jian Hua , Yao Zheng Qiang , Jin Y. , Xie H.B. , Zhao Y.S. , Xu L.Ch.
Published: March 2009

Predicting the precision of grinding process, especially correlating surface functionality generation to grinding conditions, would be of great significance to improve grinding accuracy of the end precision product. Huang developed a very promising revolutionary spectral data analysis technique based on the Hilbert transform. The concrete methods of the EMD, the local Hilbert spectrum are introduced. An artificial neural network (ANN) based on back propagation is developed to predict surface roughness Ra. An accelerometer is employed as in-process surface recognition sensor during grinding process to collect the vibration as input neurons. Changing the grinding condition, training and testing within the artificial neural networks to retrieve the weightings, the experimental results show that the proposed ANN surface recognition model is economical, efficient
and the model has a high accuracy rate for predicting surface roughness.
Thermal Model's Building and Experimental Research in Grinding Contact Zone for Plunge Grinding Process
Authors: Cheng X.M. , Wang Long Shan , Li Guang Fu
Published: March 2009

During the process of plunge grinding, a test piece can be axially grooved with
thermocouple embedded, thermo-electromotive force will be conducted through collecting ring and then after A/D converting, data will be digitally acquired and online test will be realized. Based on the thermal theories, this paper presents a simple model to calculate the workpiece’s contact zone temperature during plunge grinding process. This model can be used to predict and calculate the grinding temperature easily. An empirical formula calculating the temperature of the grinding contact surface had been obtained through multivariate linear regression analysis experiments. The thermometric system showed in this paper had solved the knotty problem that the grinding temperature was very difficult to measure for plunge grinding. Compared with traditional method, the testing method adopted by the author will give more accurate result and more closely represent the test piece situation. The results of the computer simulation and the experiments proved the
exactitude of the thermal model and the feasibility of the thermometric system.
Effects of Suspending Abrasives on the Lubrication Properties of Slurry in Chemical Mechanical Polishing of Silicon Wafer
Authors: Liu J.Y. , Jin Zhu Ji , Guo Dong Ming , Kang Ren Ke
Published: March 2009

The lubrication properties of the slurry between the silicon wafer and the pad in chemical mechanical polishing (CMP) are critical to the planarity of the silicon wafer. Moreover, the suspending abrasives, which are contained in the slurry, have an extremely important influence on the lubrication properties of the slurry. In the CMP process of the large-sized silicon wafers, the influence of suspending abrasives on the slurry becomes more prominent. In order to explore the effects of suspending abrasives on the lubrication properties of the slurry under the light load conditions, a three-dimensional lubrication model based on the micro-polar fluid theory is developed. The effects of suspending abrasives on the fluid pressure acting on the wafer and the distribution of the slurry film between the silicon wafer and the pad are discussed.
The Experimental Study on Lapping and Polishing of Metal Micro-Coil Based on Silicon Wafer
Authors: Liu B.D. , Guan Jia Liang , Li D.SH. , Li H.Q.
Published: March 2009

The removal of redundant layer of deposited metal of the micro coils is one difficult
problem in the fabricating of micro-mechanical electromagnetic relay. In view of the machining efficiency and quality, the paper introduced lapping and polishing technology. The paper also analyzed the characteristic of lapping and polishing and introduced the appropriate abrasives. Then the main procedures were presented and the measuring result was given in the paper. The surface roughness of the coil could satisfy the next layer fabricate requirements of the micro-mechanical
electromagnetic relay. At last the paper concluded the optimized lapping and polishing parameters.
Study on the Modeling and Experiments for the Virtual Axis Hybrid Polishing Machine Tool by the Flexible Multibody Dynamics
Authors: Yu Miao , Zhao Ji , Ma W.T.
Published: March 2009

The virtual axis hybrid polishing machine tool (VAHMPT) is the novel equipment
developed by the authors that is aimed at the precision machining on the free-form curved surfaces. This paper establishes the dynamic equations of the spatial rigid-flexible coupling multibody systems considering the coupling for the rigid movement of the whole VAHMPT with the elastic deformation of each leg by means of the theory of dynamics of flexible multibodysystems. Meanwhile the dynamic characteristics of the hybrid machine tool is studied in detail by the dynamics simulation analysis. The dynamic simulation of the machine shows that the elastic
deformation of each leg is very small during the movement of the machine and the influence of the flexibility of each leg on the trace of moving platform is not obvious due to the characteristics of joints. The dynamic characteristics of the VAHPMT is verified combining with the experiments. It is shown that the experiments result is almost accorded with the simulation analysis. The satisfied polishing effect on the curved surfaces can be obtained and the demand of the polishing can be
achieved by the VAHPMT.
Research of Control Track Calculating Methods for Free Curved Surface NC Grinding
Authors: Wang Ke , Chen X. , Fu Y.S. , Sun Xing Wei , Li Hang
Published: March 2009

In this paper the basic principle for the free curved surface NC grinding is introduced, and then the influencing factor of envelope control track, the key question of free curved surface NC grinding, is analyzed. Finally, in this foundation, according to the principle of “minimum directed distance” the thought of the free curved surface NC grinding control track calculating method is put forward.
Ultrasonic Dressing of Grinding Wheel and Its Influence on Grinding Quality
Authors: Jiao Feng , Zhao Bo , Zhu Xun Sheng , Fan Q.T.
Published: March 2009

Being a key step in grinding process, dressing of grinding wheel influences the whole
grinding results, especially grinding quality. Because of its good dressing effect, a new dressing method assisted by ultrasonic vibration attracted researchers’ attention. In this paper, on the basis of the researches on dressing with single-point diamond dresser, physical model of ultrasonic dressing of grinding wheel were established. According to the physical model and the SEM photos of grinding
wheel’s surface topography, the mechanism of ultrasonic dressing was brought to light. Through contrast experiments, based on roughness and micro-feature of the ground surface, the influence of ultrasonic dressing on grinding quality was researched.
Modeling and Analysis of Lead Frame Structure in Electronic Packaging Using Java and ANSYS
Authors: Min Seung Jae , Lee Hyoung Seok
Published: March 2009

As the larger capacity and smaller packaging size are required in the design of a
semiconductor, areas and pitches of solder joints have been miniaturized. Therefore the importance of bondability and reliability in soldering technique for the printed circuit board design has been increased since the fatigue failure has been observed at the place between the lead frame and solder joints. To evaluate thermal reliability of SMD type electronic packaging such as SOIC, PLCC and BGA, an exclusive module for modeling a lead frame structure is developed using JavaScript and the
thermal stress analysis is performed using ANSYS. A modeling program with GUI can define geometric dimensions of an electronic packaging, assign material properties of a lead frame and a solder and apply boundary conditions. A seamless integration between modeling and analysis is achieved by implementing an interface program to generate an analysis model of a lead frame structure directly from the model information. Heat transfer analysis and stress analysis considering thermal loading are carried out in ANSYS and the results are exploited to estimate the fatigue life of a lead frame based on the S-N curve. The effect of different lead frame materials is examined to identify the mechanical characteristics and the different shapes of the lead frame with same SMD type are investigated to distinguish the reliability.
Synthesis and Characterization of Nanocrystalline CeO2
Authors: Hadi Abdul , Yaacob Iskandar Idris
Published: March 2009

Nanocrystalline CeO2 has been synthesized at room temperature using water-in-oil (w/o) microemulsion technique. The structure and properties of the nanocrystalline CeO2 were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and gas adsorption desorption measurement. XRD results showed the synthesized CeO2 has a face centered
cubic structure with crystallite size of about 5.2 nm. TEM observation also indicated the presence of nanometer sized particles of CeO2. Coarser particles were also observed due to agglomeration. Gas adsorption desorption isotherms showed the behavior of fine particles with mesoporous structure.
Design and Manufacturing of IDEAL with Stacked Ceramic Layers and Inter-Digitated Electrodes
Authors: Yoon Kwang Joon , Lee J.D. , Kim K.B. , Park Hoon Cheol , Goo Nam Seo
Published: March 2009

This paper is concerned with the development of stacked ceramic thin actuation layer IDEAL (Inter-Digitated Electrode Actuation Layer) using d33 actuation mechanism of piezoelectric ceramic. Most of the thin piezoelectric actuators are operated with d31 actuation mechanism. Many kinds of piezoelectric ceramic actuators are strived now to improve the actuation performance. One of efforts to improve performance of piezoceramic actuators is the research trying to develop an actuator using the piezoelectric coefficient d33. The piezoelectric coefficient d33 is almost twice larger than piezoelectric coefficient d31. Therefore, the induced strain of PZT thin layer with d33 actuation mechanism is bigger than that with d31 actuation mechanism. The AFC and LaRC-MFC used d33 actuation mechanism with surface interdigitated electrode to enhance its actuation performance. But their actuation mechanism is not perfect d33 actuation mechanism since the interdigitated electrodes are placed at the surface of the actuation layer. In this research, the stacked ceramic thin actuation layer with imbedded inter-digitated electrodes is designed and manufactured. The actuation strain of stacked ceramic thin actuation layer is measured and compared with the actuation strain of the LaRC-MFC. The comparison shows that the developed stacked ceramic thin actuation layer can produce 10% more actuation strain than LaRC-MFC at relatively high electric field.
Influence of Electric Fields on the Fracture Behavior of Ferroelectric Ceramics under Combined Electromechanical Loading
Authors: Liu Zhan Wei , Fang Dai Ning , Xie Hui Min
Published: March 2009

In this paper, fracture behavior of ferroelectric ceramics under combined electromechanical loading was investigated using moiré interferometry. It is found that the influence of electric field on fracture toughness is not very larger in the case that the directions of the poling, electric field and crack extension are perpendicular to each other. When the poling direction is parallel to the crack extension direction and both are perpendicular to the electric field direction, the normal strain measured reduced faster than that calculated by FEM with and without electrical loading as the distance away from the crack tip increases. Fracture toughness decreases obviously as the electric-field intensity increases.
Bleustein-Gulyaev Waves in an Inhomogeneous Layered Piezoelectric Half-Space
Authors: Peng Fei , Liu Hua Rui
Published: March 2009

The propagation of Bleustein-Gulyaev (BG) waves in an inhomogeneous layered
piezoelectric half-space is investigated in this paper. Application of the Fourier transform method and by solving the electromechanically coupled field equations, solutions to the mechanical displacement and electric potential are obtained for the piezoelectric layer and substrate, respectively. The phase velocity equations for BG waves are obtained for the surface electrically shorted case. When the layer and the substrate are homogenous, the dispersion equations are in agreement with the corresponding results. Numerical calculations are performed for the case that the layer and the substrate are identical LiNbO3 except that they are polarized in opposite directions. Effects of the inhomogeneities induced by either the layer or substrate are discussed in detail.
The Effect of Residual Stress on Fatigue Crack Growth of Multi-Pass Welds
Authors: Lee Seung Gun , Kim Jong Sung , Park Jin Seok , Jin Tae Eun
Published: March 2009

The multi-pass welding generates residual stress which may change fatigue crack growth rate and impair the lifetime of nuclear welded structures. In this paper, we performed fatigue test with notched specimens and evaluate the effect of residual stress on fatigue crack growth rate of welds. In order to identify the magnitude of residual stress, the residual stress was measured by HDM (hole drilling method) and residual stress analysis was performed by using FEM (finite
element method). In order to review the effect of residual stress on fatigue crack growth rate, the fatigue crack growth analysis was also performed to determine the fatigue crack growth curves by using FEM and ASME B&PV Code, Sec.XI, App.A. Finally, as a result of comparison among the fatigue crack growth curves, it is found that the fatigue crack growth rate was quite different according to the crack location even if the residual stresses are considered.
Damage Evaluation of Automatic Belt Tensioner Using with FTP-75 Mode
Authors: Jung Do Hyun , Song Sell , Shin Pilsu , Bae Sung In
Published: March 2009

Automatic belt tensioner for stabilization of Engine accessory belt system is made
increase its life, decrease noise and vibration and increase its commercial value. Therefore, it is important finding test mode to assess life of automatic belt tensioner. However, measurement and analysis test result in practical test condition on real road needs requiring much test time and finance. In this study, there is analyzed and established test mode which is loaded measured equivalent damage in real working condition, compared test condition of pre-established test mode and FTP- 75 mode of fuel efficiency test and verified advantages and disadvantages of each mode. Because FTP-75 Mode is for measuring fuel efficiency related with engine, applying FTP-75 mode is estimated suitability for test of engine accessory. Comparison and assessment of damage is investigated structure and pulley part. Equivalent damage is calculated with Palmgren-Miner Rule and representative stress method, test condition of automatic belt tensioner is investigated. This investigation is regarded as being useful to life evaluation of both automatic belt tensioner and other engine accessory component.
Strength Design and Minimization of Residual Stresses in Reversible GaAs Wafer Bonding Process
Authors: Choi S.T. , Song Jun Yeob , Kim Jae Hyun , Lee S. , Earmme Y.Y.
Published: March 2009

The GaAs wafer bonding process is investigated to reduce the mechanical failures of GaAs wafer based on strength design concept. Three-point bending experiment is performed to measure the fracture strength of GaAs wafer, of which cleavage takes place on (110) plane. We propose a simple method for minimizing the thermal residual stress in a three-layer structure, of which the basic idea is
to use an appropriate steady-state temperature gradient to the wafer bonding process. The optimum bonding condition of GaAs/wax/sapphire structure is determined based on the proposed method. The effect of material anisotropy on the thermal residual stress is also analyzed by finite element method.
Discussion on the Use of Parameters of Drucker-Prager Criterion
Authors: Wang Shui Lin , Jiao Yu Yong , Xiao Haibin , Li Chun Guang
Published: March 2009

There are several different yield surfaces of Drucker-Prager yield criterion which
corresponds to Mohr-Coulomb yield criterion in principal stress space. The different yield surfaces are determined by parameters in Drucker-Prager criterion. The influence of the different parameters on computational results is discussed in the paper, and the use of the equivalent Drucker-Prager criterion to Mohr-Coulomb criterion is suggested when elastoplastic analysis is performed in engineering problems.
Analysis for Initiative Sub-Crack of Ellipse Fracture
Authors: Zhang Dun Fu , Zhu Wei Shen , Li Shu Cai
Published: March 2009

By use of complex variable theory, formulae for tangential stress on ellipse edge are
derived. Sub-crack point, opening angle and maximal tangential stress on ellipse edge are studied under uniaxial compression, biaxial compression, or uniaxial compression and crack water pressure separately. Based on the maximal tension stress criterion, formulas of maximal tangential stress and critical load are presented. The results show that sub-crack point, opening angle, maximal tangential
stress and critical load are varied with different aspect ratio and different inclined angle. Meanwhile, the most dangerous inclined angle is obtained.
Super Long Life Fatigue of AE42 and AM60 Magnesium Alloys
Authors: Wang Q.Y. , Zhang Hong Yan , Sriraman S.R. , Liu S.L.
Published: March 2009

Magnesium alloys, on account of their lightweight, find useful applications in the
automotive sector. During service, they experience very high number of fatigue cycles. Therefore, the understanding of their long life fatigue behavior becomes extremely important. This is possible by using ultrasonic fatigue testing, which is the only feasible way of doing it. In this study, the two such alloys viz. AE42 and AM60 has been investigated for their long life fatigue characteristics under fully reversed loading conditions, using a piezoelectric fatigue testing machine operating at a frequency of 20 kHz. The S-N data does not reach a horizontal asymptote at 107 cycles in either of the alloys. However, the alloy AM60 seems to show a fatigue limit at about at 109 cycles. The fractures examined by scanning electron microscopy (SEM) were found to be brittle in character. In very high cycle fatigue conditions, the crack was found to initiate from the specimen subsurface.
Damage Identification of an Automotive Engine Based on Detection of Impact Vibration Using an Adaptive Filter
Authors: Lee Sang Kwon , Gu Jinhoi , Cho Byung-Og
Published: March 2009

In an automotive engine, faults induce impulsive vibrations and thereby degrade engine performance, making it important for an automotive engineer to detect and analyze impulsive vibration signals for fault diagnosis. However, detecting and identifying impulsive signals is often difficult because of interfering signals such as those due to engine firing, harmonics of crankshaft speed and broadband noise components. These interferences hinder early fault detection. To overcome this difficulty we present a two-stage ALEF (Adaptive Line Enhancer Filter) that is capable of enhancing impulsive signals embedded in background noise. This method is used to pre-process signals prior to time-frequency analysis via higher order methods such as the combined higher order time-frequency.
Finite Element Analyses of Cylinder Problems Using Pseudo General Plane Strain Elements (Planar Constraint)
Authors: Kwon Young Doo , Kwon Hyun Wook , Jung Young Chul
Published: March 2009

A long cylinder composed of periodic structures along the axis can not be treated as a general plane strain(GPS) state, because within a repeated module, the geometry and loading condition may not be uniform along the axial direction. For this kind of situation, a ‘ more general kind of GPS ’ finite element is needed that uses a set of ‘ planar constraints ’, hereinafter called a ‘ pseudo general plane strain(PGPS) finite element ’. Otherwise, a high number of constraints need to be used, which is a tedious job and often gives rise to an input error. Plus, this can also cause a numerically ill conditioned stiffness matrix that results in a trivial or diverged solution. Accordingly, this study proposes several PGPS finite elements that use a set of planar constraints to solve long periodic cylinder problems, as well as conventional long cylinder and plane strain problems.
The FEM Simulation and Full-Scale Blast Tests for Crack Deceleration in Gas Pipeline
Authors: Huo Chun Yong , Yang Xiao Bin , Zhuang Zhuo , Maitirouzi Julaiti , Feng Y.R. , Zhuang C.J.
Published: March 2009

Preventing pipeline from rapid crack propagation is a critical issue to avoid casualties and disasters. In this paper, by combining the energy balance theory with FEM simulation and arrest criteria, the numerical analysis is developed to solve the problem of crack dynamic propagation in gas pipeline. This simulation, in combination with the full-scale blast tests, provides a broad prediction of the dynamic fracture process. The crack tip opening angle (CTOA) criterion is consummated through the comparison between CTOA in FEM calculation and the critical value of (CTOA)C obtained by the experiment. The result of the simulation for the crack speed and location is consistent with data by Alliance and Japanese full-scale blast tests.