bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Mode I Quasi-Static Growing Crack Field in the Pressure-Sensitive Dilatant Material
Authors: Yang Yong , Wu Guo Hui , Tang Li Qiang , Li Ning
Published: November 2010

A mechanical model of the pressure-sensitive dilatant material is established in order to investigate the viscous effect in mode I quasi-static growing crack-tip field. The constitutive equations on the pressure-sensitive dilatant material are deducted. Through asymptotic analysis, it is shown that in the stable creep growing stage, the elastic-deformation and the visco-deformation are equally dominant in the near-tip field, as . The asymptotic solutions of separative variable in the crack-tip field of plane stress mode I quasi-static are aslo obtained. According to numerical calculation, the curves of stress, strain and displacement in terms of various parameters are given. The asymptotic solutions of quasi-static growing crack-tip field gained here can conveniently degenerate the incompressible case, when the Poisson ratio , named as HR field. The conclusions can provide the references for further studying the dynamic growing crack-tip field in the pressure-sensitive dilatant material.
The Failure Mechanism Analysis on a Reinforced Concrete Frame Structure in Beichuan County - The Heavy Disaster Areas of Wenchuan 8.0 Earthquake
Authors: Yan Pei Lei , Sun Bai Tao , Zhou Qiang
Published: November 2010

On 12 May 2008, a magnitude 8.0 earthquake happened in Wenchuan, Sichuan province, China .It was the most serious earthquake in china since 1949, causing very huge casualties and engineering damages to the buildings. In the earthquake, a reinforced concrete frame structure of Beichuan Hotel in Beichuan County collapsed completely because of the unsuitable arrangement of column network, and the engineering damage was characteristic. In the paper, the properties of material nonlinearity were considered ,the nonlinear analysis model of reinforced concrete frame structure was established, the time history analysis and nonlinear static analysis were used during inelastic stage, the main cause of structural destruction was obtained, the influence of the arrangement of column network on the structure was discussed.Therefore ,the results can provide valuable reference for the seismic design of reinforced concrete frame structure.
Study on Fracture Behaviors of Injection-Molded Bamboo Fiber/PBS Composites
Authors: Ohkita Kazuya , Takagi Hitoshi
Published: November 2010

Injection-molded bamboo fiber/PBS (polybutylene succinate) composites were studied; especially much attention was focused on their fracture behavior. The effects of filling rate and size of the bamboo fiber (BF) to the resin on fractural behavior were evaluated by tensile and Izod impact tests. The tensile strength of the composites of BF particle size the range from +75 to -180 m and from +180 to -250 m were higher than those of -75 m and those of +250 to -500 m. However, there are many pull-out fibers on fracture surface. The surface of the fiber had no sticking of PBS resin. The impact strength of the composites increased with increasing BF content except for the case that BF particle size was -75 m. After impact tests, in the case of the composites prepared using large BF, the fractural surfaces became bumpy. The changes in shapes of the composites derived from immersion in boiling distilled water were examined by using a digital microscope. After immersion in the hot water, many cracks appeared on the outer surface of the composites. These cracks might be responsible for the brittle fracture behavior of the water-absorbed composites.
Three-Dimensional Surface Heat Transfer Coefficient and Thermal Stress Analysis for Ceramics Tube Dipping into Molten Metal
Authors: Takase Yasushi , Li Wen Bin , Hendra Hendra , Ogura Hiroki , Higashi Yusuke , Noda Naoaki
Published: November 2010

The low pressure die casting machine has been used in industries because of its low-cost and high efficiency precision forming technique. In the low pressure die casting process is that the permanent die and filling systems are placed over the furnace containing the molten alloy. The filling of the cavity is obtained by forcing the molten metal, by means of a pressurized gas, to rise into a ceramic tube, which connects the die to the furnace. The ceramics tube, called stalk, has high temperature resistance and high corrosion resistance. However, attention should be paid to the thermal stress when the ceramics tube is dipped into the molten metal. It is important to reduce the risk of fracture that may happen due to the thermal stresses. To calculate the thermal stress, it is necessary to know the surface heat transfer coefficient when the ceramics tube dips into the molten metal. In this paper, therefore, the three-dimensional thermo-fluid analysis is performed to calculate surface heat transfer coefficient correctly. The finite element method is applied to calculate the thermal stresses when the tube is dipped into the crucible with varying dipping speeds and dipping directions. It is found that the thermal stress can be reduced by dipping slowly when the tube is dipped into the molten metal.
Single and Double Edge Interface Cracks in a Bonded Plate under Arbitrary Material Combination
Authors: Lan Xin , Noda Naoaki , Zhang Yu , Kengo Mitinaka
Published: November 2010

Although a lot of interface crack problems were previously treated, few solutions are available under arbitrary material combinations. This paper deals with a single edge interface crack as well as a double edge interface crack in a bonded plate. Then, the effects of material combination on the stress intensity factors are discussed. A useful method to calculate the stress intensity factor of interface crack is presented with focusing on the stresses at the crack tip calculated by the finite element method. Then, the stress intensity factors are indicated in charts under arbitrary material combinations. Specifically, some necessary skills as refined mesh and extrapolations of the stress intensity factors are used to improve the accuracy of the calculation. It has been proved that the values shown in this paper have at least 3-digit accuracy. For the edge interface crack, it is found that the dimensionless stress intensity factors are not always finite depending on Dunders’ parameters , . For example, they are infinite when . And they are finite when , and zero when .
Stress Intensity Factors of a Crack on the Interface of Adhesive and Adherents
Authors: Zhang Yu , Noda Naoaki , Lan Xin , Takaisi Kentarou
Published: November 2010

Adhesive joints are widely used as the joints with the same or different adherents, such as in engineering and electric devices. However, because of mismatch of different materials properties, failures due to crack initiation and propagation are often observed on the interface between adhesive and adherents. Therefore, it is important to analyze stress intensity factor of crack on the interface. In this paper, the effect of material combination of adhesive and adherents on stress intensity factor and effect of the thickness of adhesive on stress intensity factor are discussed. A useful method to calculate the stress intensity factor of interface crack is presented with focusing on the stresses at the crack tip calculated by finite element method. The stress intensity factors are indicated in charts under different thickness of adhesive . It is found that the intensity of singular stress first increases with increasing , then decreases from about , and keeps constant from about , when is the width of adhesive. These results are helpful to design dimensions of devices and choose appropriate materials when adhesives are used inside of them.
Fatigue Behavior of Bridge Steel in Very Long Life Region
Authors: Nu Yan , Chen Yi Yan , Jiang Rui Juan , Fang Dong Hui , Wang Qingyuan
Published: November 2010

Q345qC steel is widely used in corrugated steel web. In this paper, the fatigue strength of Q345qC steel between 105~109 cycles was investigated using the ultrasonic fatigue testing technique, with a loading frequency of 20 kHz. The fracture surfaces of specimens were observed with scanning electron microscopy (SEM). The experimental results show that the S-N curve of Q345qC steel continues to decrease with the increase of the number of cycles between 105 and 109 cycles and does not generally exhibit a plateau beyond 107 cycles. The observation of fracture surface shows that the mechanism of fatigue failure is similar in both case of ultrasonic fatigue and conventional fatigue in long life regime. Cracks initiate from a mass defect of specimen surface or an interior inclusion.
Effect of H2 Gas Environment on Low Cycle Fatigue Crack Initiation and Damage Accumulation of 304 Stainless Steel
Authors: Iino Y.
Published: November 2010

Notched compact tension specimen of 304 stainless steel (0.8CT, notch tip radius of 1mm, thickness of 6mm) was low-cycle-fatigued at room temperature at stress ratio of -1 in 99.9999% H2 and in pure air at 1 and 0.1 Hz at apparent stress intensity factor of 34.4MPa . The H2 acceleration of both crack initiation and growth at notch is significant: 3-4 times faster than pure air. The accumulated plastic zone was analyzed by the recrystallization technique. It is shown that the accumulated plastic zone in H2 is smaller than in pure air.
Damage Identification Using Lamb Waves
Authors: Sharif-Khodaei Z. , M.H.Aliabadi Ferri
Published: November 2010

The concept of damage detection using sensors in composite panels is of growing interest, due to the reduction in maintenance activity and increasing of the aircraft safety. Piezoelectric materials have been widely used to build a variety of transducers for activating and receiving Lamb waves which are used for delamination/damage detection. The aim of this paper is to use smart structures for detecting and locating damage in composite panels, by using piezoelectric patches as both sensors and actuators.
Effects of Stitching Parameters of Non-Crimp Fabrics on the Mechanical Properties of CFRTP
Authors: Tanaka Kazuto , Yamada Masahiro , Shinohara Masahiro , Katayama Tsutao
Published: November 2010

The non-crimp fabric (NCF) have an advantageous combination of high material properties and low cost for processing, and overcomes the disadvantages of the crimp factor of woven fabrics, providing full use of modulus and strength of reinforcing fibre. For using NCF, different stitching tension and thread of non-crimp fabrics may cause the mechanical properties of CFRTP. In this study, it is aimed to clarify the effect of stitching tension and thread of non-crimp fabrics on tensile strength of CFRTP. The disorder degree of the thickness direction in the fibre bundle and the ratio of resin rich area were examined by the SEM image analysis. There is the inverse correlation between tensile strength and the disorder degree to the thickness direction in the fibre bundle.
The Dynamic Mechanical Properties Study of Aluminum Alloy Honeycomb Material and its Numerical Simulation
Authors: Zou Guang Ping , Chang Zhong Liang , Wang Xin Zheng , Liu Bao Jun , Chen Si
Published: November 2010

Light weight aluminum alloy honeycomb materials are ideal lightweight structure
materials, which have higher specific strength and stiffness, and widely applied in aviation, aerospace,
automobile and so on, and also it is an ideal material for damping, buffering, heat insulation and
energy absorption. In this paper, the SHPB technique which the aluminum alloy bar diameter is
37mm is used for studying the dynamic mechanics property of the lightweight aluminum alloy
honeycomb materials which the diameter is 30mm, and then to study the dynamic mechanical
properties of the material, from the results we can see dynamic strain-stress curves can be divided into
three phases, elastic phase, stress platform and compaction phase. And the numerical simulation
method was used for study the dynamic deformation process of the honeycomb panel material under
impact load, and also compare the results with the specimen cell figures which were observed by the
microscope.
Development of Optical Sensor for Detecting Micro Crack on Contact Surface
Authors: Yazawa Takanori , Otsubo Tatsuki , Fukuda Youhei , Ogiya Yasuhiko , Kojima Tatsuhiro
Published: November 2010

This paper discuses the development of the optical sensor due to detect the micro crack and measure the surface property of the contact surface in the equipment. To measure the surface property is an index for detecting no uniformity contact and / or micro crack on the contact surface. So, there is demand of the development of the sensor to measure the surface property in using equipment. This sensor has two optical systems, called stylus and skid, to reduce the influence of vibrations on the measurement result. The stylus measures the surface property with the vibration, and the skid measures only the displacement between the sensor and the objective surface at the same place as the stylus, i.e. the vibration. Therefore, the stylus signal minus skid signal shows the surface property. In this research, the proposal of the principle of this system, the methods of the development and the evaluation of the stylus system of the sensor and the development of prototype sensor is described.
Determination of Fatigue Limit by Mono-Axial Tensile Specimens Using Thermal Analysis
Authors: Risitano Antonino , Clienti Carmelo , Risitano Giacomo
Published: November 2010

In this work is indicated how it could be possible to evaluate the limit stress of the thermo-elastic phase of deformation by thermo-analysing the surface of the specimen during a static traction test. Adding the temperature curve measured on a small area of the surface (the hottest) to the classic stress-strain curve, it is possible to evaluate a limit temperature T0 coincident with the beginning of the non linear trend of the curve. The corresponding stress value is coincident with the fatigue limit of the analyzed component. As an example, the results of traction tests performed on two notched specimens, where the change of linearity in the temperature curve during static traction test was evident, are reported.
Finite Element Analysis for Optimal Heating Condition in Thermal Stress Cleaving of Brittle Materials Using Laser Irradiation
Authors: Motomura Fumitaka , Saimoto Akihide
Published: November 2010

An optimal condition of thermal stress cleaving was investigated by assuming the element-by-element temperature rise situation using finite element method. The obtained thermal stress cleaving condition is found to be optimal for the symmetrical cleaving of a rectangular plate.
Multiaxial Fatigue Evaluation of ST52-3N Structural Steel
Authors: Moreno Belen , Lopez-Crespo Pablo , González-Herrera Antonio , Zapatero Jose
Published: November 2010

Many mechanical components are subjected to multiaxial fatigue. These conditions are typically coming from external loads, the geometry of the component and/or residual stresses. However the majority of experimental data available in the literature are focused on the simpler uni-axial fatigue problem. The present work describes a series of experimental tests conducted to characterise in a comprehensive way the multiaxial behaviour of a ST52-3N structural steel. First, the monotonic properties of the steel were obtained experimentally. Then cyclic properties were also measured both in the longitudinal and torsional axes. Finally another series of tests were carried out to study the multiaxial response of the material. Both in-phase (proportional) and out-of-phase (non proportional) loadings were employed, thus providing a complete database for improving current models which describe the multiaxial behaviour of materials.
On the Crack Initiated from the Bi-Material Notch Tip
Authors: Profant Tomáš , Klusák Jan , Kotoul Michal
Published: November 2010

The bi-material notch composed of two orthotropic parts is considered. The radial and tangential stresses and strain energy density is expressed using the Stroh-Eshelby-Lekhnitskii formalism for the plane elasticity. The potential direction of the crack initiation is determined from the maximum mean value of the tangential stresses and local minimum of the mean value of the generalized strain energy density factor in both materials. Matched asymptotic procedure is used to derive the change of potential energy for the debonding crack and the crack initiated in the determined direction.
Statistical Analysis of Seismic Vulnerability for Various Types of Building Structures in Wenchuan Earthquake
Authors: Sun Bai Tao , Zhang Gui Xin
Published: November 2010

Based on the nearly 5,000 building samples investigated on site, damage characteristics of different types of building structures which located in different intensities regions are described and the reasons are analyzed in this paper. Three kinds of structural damage characteristics have been summarized as follows: 1) fortified masonry structures and unfortified ones; 2) masonry buildings with bottom frame; 3) reinforced concrete frame structures. The damage ratio of these three kinds of buildings in different intensities is obtained and the vulnerability has been compared. It provides the reference for those people who work for earthquake engineering to know the earthquake damage of different types of structures with fortified or unfortified. Also it provides important reference for revising seismic design code.
Effect of Friction on the Stress Field Strength of Gear Cracks
Authors: Li You Tang , Chen Bo , Wang Rui Feng
Published: November 2010

Based on elasticity theory, the stress field and stress intensity factor of gear crack are discussed. The effect of friction coefficient and crack shape on equivalent stress, displacement at crack tip and stress intensity factor were analyzed by using general finite element software ANSYS, and the formula of stress intensity factor of gear crack was revised. The results showed that the equivalent stress, displacement at crack tip and stress intensity factor increased with the friction coefficient for the same crack. For the same f and different a/c, the front friction surface played a major role when a/B﹤0.05, and the post friction surface played a major role when a/B﹥0.05. The stress intensity factor increase at first, and then decrease with the increase of a/c.
The Application of Neural Networks in the Reliability Evaluation of Structures
Authors: Hu Wei Bing , Yu Hai Pin
Published: November 2010

According to the Chinese Structure Code and engineering experience, the factors affecting the reliability of structures are properly qualified as input parameters; this paper mainly researches the application of neural networks in the reliability evaluation of structures. Comparisons are made between the traditional methods of reliability evaluation of established structures and the method put forward in this paper. It is found that the method put forward in this paper is practicable, reliable and effective. Meanwhile, the weaknesses of the traditional reliability evaluation of structures, that is, long period of evaluation, huge and tedious calculation and arbitral judgments, are avoided with the introduction of the new method in this paper.
Study on High Temperature Creep Behaviors of P92 Steel
Authors: Zhang Naiqiang , Xu Hong , Mao Xue Ping , Wang Gang
Published: November 2010

The creep experiments are performed under the various stresses at 595°C, 610°C, 640°C and 670°C for P92 steel which broadly used in USC plant pipeline. The specimens are taken from the extrados part of a new manufactured main steam elbow. A series of integrated creep curves are obtained, and the maximal test time last over 13000h. The relationship between the minimum creep rate and stress at different temperatures is explained by Norton formula. Both the 105 h creep rupture strength and stress of 1% creep strain in 105h of P92 steel at the four above temperatures are extrapolated with a list by using the Monkman-Grant formula, which are consistent with the reference experiment data at 600°C and 650°C. Meanwhile, damage during the creep process is discussed applying Norton creep damage formula and θ function method.
A Comparative Study of Different Biaxial Fatigue Models
Authors: Lopez-Crespo Pablo , Moreno Belen , Zapatero Jose
Published: November 2010

There are a number of theories available to model biaxial fatigue problems. Among these, the critical plane models try to predict not only the fatigue life but also the orientation of the crack or failure plane. This work attempt to analyse the biaxial tension-torsion problem from a strain-based analysis focused on plane failures predictions. Fatigue life and critical plane predictions are carried out applying multiaxial models proposed by Brown-Miller, Fatemi-Socie and Smith-Watson-Topper. The theoretical results are compared with constant amplitude test data, in-phase and out-of-phase (90˚) in a structural steel. The results suggest that Smith-Watson-Topper model predictions of fracture plane do not match the real fracture plane. The critical fracture plane predictions of the Brown-Miller and Fatemi-Socie models do not match in most cases with experimental observations either, but considering the second plane of the maximum shear strain amplitude, the predictions of the fracture plane and fatigue life improve substantially.
On Damage and Fracture Mechanics of Shaft Lining under Complicated Loads with Freezing Method
Authors: Liu Bin , Liu Quan Sheng
Published: November 2010

Based on the stress characteristics of freeze shinking shaft lining at construction and operation stages, it is set up that The anisotropic damage model including initial damage, which suit to make Damage and Fracture Mechanics analysis for the shaft lining. A 3 dimensional anisotropic damage program is compiled using FEPG software, which take the following factors into consideration: temperature, conduction conditions, concrete facture energy and its aggregate gradation. Take the liangbosi mine shaft lining for example, its damage evolutionary process under complicated stresses such as permanence field stress, the gravity and vertical additional stress changed with time is obtained. It is discussed that the facture’s position and its development process, and the mechanical mechanics of the shaft lining structure failure.
Finite Element Analysis on Structural Behaviours of Single Shear Cold-Formed Stainless Steel Bolted Connections with Two Bolts
Authors: Lee Yong Taeg , Kim Tae Soo , Lim Jin Seong , Kim Seung Hun
Published: November 2010

The experimental research for single shear bolted connection of cold-formed stainless steel fabricated with two bolts (2×1 bolt arrangement) has been conducted by T.S. Kim etc. Plate thickness and end distance parallel to the direction of loading was considered as main variables. It is found that the curling occurred easily in bolted connections with a long end distance and thinner plate. In this paper, finite element analysis study has been performed in order to compare test results with the predicted results and to investigate in detail the ultimate strength and curling influence. Finite element analysis(FEA) procedures also were introduced. FE models of connections with restrained out of plane deformation were also simulated for comparison with the curled models.
Therefore, the validation of FEA in predicting ultimate strength and curling behavior was verified and the strength reduction ratio caused by curling was estimated.
An Experimental Study on Structural Behaviours of Single Shear Cold-Formed Stainless Steel Bolted Connections with Two Bolts
Authors: Kim Tae Soo , Kim Min Seung , Shin Sung Woo
Published: November 2010

The application of stainless steel in buildings has been increased gradually with excellent life cycle cost for ensuring the sustainability in structures for the reduction of green house gas emission. Especially, the purpose of this paper is to investigate the structural behaviors such as ultimate strength, fracture mode and out of plane deformation, i.e., curling of single shear bolted connection of cold-formed austenitic stainless steel with two bolts (2×1 bolt arrangement). Plate thickness and end distance parallel to the direction of applied force are considered as main variables. The curling was also observed in the bolted connections with a long end distance and edge distance as the previous researches. Curling occurrence resulted in the change of fracture modes in connections with same bolt arrangement and end distance and ultimate strength reduction.
Stress Intensity Factors for Surface Semi-Elliptical Crack in Cylindrical Specimen under Combined Torsion and Axial Compression
Authors: Horníková Jana , Šandera Pavel , Pokluda Jaroslav
Published: November 2010

Some authors proposed to combine a torsional loading of cylindrical specimens with surface semi-elliptical cracks (the principal axes along the axial direction) with superimposed static axial compression in order to eliminate kinking or branching of shear cracks from the shear plane. To authors’ knowledge, however, no precise numerical analysis of such a loading configuration is currently available. The aim of this article is to calculate stress intensity factors KI, KII and KIII along the semi-elliptical crack front using the ANSYS code. The problem is solved for a semi-circular crack front and various crack inclination angles. The results reveal that the compressive loading cannot eliminate the branching process. The inclination of the crack plane induces a rather high opening mode which means that the microscopically tortuous fatigue cracks observed in experiments grew under mixed-mode I+II+III.
Strength Analysis of Chassis Structure for Medium-Sized Low-Floor Vehicle under Dynamic Load Cases
Authors: Kim Yeon Su , Moon Kyeong Ho , Chang Se Ky , Mok Jai Kyun
Published: November 2010

For the medium-sized low-floor bus, backbone structure of chassis was designed to have light-weight structure with SAPH (Steel Automobile Press Hot rolled) 440. Strength for the designed backbone structure was also analyzed by finite element method under various dynamic load cases considered in this paper. On the basis of the analysis results, the structural safety for the designed backbone structure was evaluated and discussed in this paper.
Experimental Investigation on the Residual Stresses Induced by a Plastic Forming Process
Authors: Lamanna Giuseppe , Grassia Luigi , Ascione Vascione
Published: November 2010

The extrusion of a space frame must be followed by forming operations of some kind to obtain the desired shape/curvature, for example a stretch bending process. Therefore, one has to face with problems as production tolerances and cross-sectional distortions of the curved product. In house experience combined with trial–and–error procedures have been traditionally used to cope with the said problems.
Aircraft frames show significant residual stresses as a consequence of plastic forming processes. A great number of variables, such as initial frame length and/or final additional stretch, can influence the stress state of frames determining their life and efficiency under operating loading conditions.
In the present paper, we refer about the experimental evaluations of the residual stress state of aircraft frames which have carried out taking into account different process parameters. The experimental results obtained and discussed show some interesting trends: they demonstrate that the residual stresses of the formed component can be controlled and reduced.
Calculation of Stress Intensity Factor under Mixed Mode Biaxial Tensile Load by Photoelastic Hybrid Method
Authors: Shimamoto Akira , Ohkawara Hiroshi , Nam Jeong Hwan , Hawong Jai Sug
Published: November 2010

In this study, the photoelastic experiment hybrid method was introduced and applied to the fracture problems of the isotropic polycarbonate plate with a central crack under the uniaxial and equibiaxial tensile load. The influences of equibiaxial tensile load on the isochromatic fringes and stress fields, stress intensity factors near the mixed mode crack-tip were investigated. As the results, without relation to the inclined angle of crack, the asymmetric isochromatic fringes around the crack propagation line under uniaxial tensile load has become symmetric and the slope of isochromatic fringe loop has inclined toward crack surface when an equal lateral tensile load was added. Furthermore, the distribution of all stress components have changed from asymmetric shape to symmetric shape, and only the range of compressive stress of σχ/σ0 have changed as compared with the mode I condition under unaxial load with β = 0°. When an equal lateral tensile load was added to uniaxial load, the value of stress intensity factors are little changed when β = 0° but the values of KI /K0 are increased and KII /K0 are become zero, that is, mode I situation when β = 15°~45°.
Molecular Dynamics Study on Interaction between Voids for Pure Aluminum
Authors: Xu Shu Sheng , Zeng Xiang Guo , Chen Hua Yan
Published: November 2010

The voids in pure Aluminum always exit in the manufacturing process. The Modified Embedded Atom Method (MEAM) potential is employed in the molecular dynamics (MD) simulation at atomic scale to investigate the interaction between voids under the impact loading for pure Aluminum. The distance between the voids distributed along the loading orientation affects the failure mechanism seriously. The results show that there are 3 kinds of mechanisms with the change of the distance between voids: 1) coalescence takes place within a critical distance between voids under extra loading, 2) when the distance between voids reaches a certain value, each void cracks at 4 locations along with the slide direction <110> of face-centered cubic (fcc), respectively, 3) a stress shield zone appears when the ligament between the voids is at the size between the cases mentioned above, which brings out the phenomena that each of the voids cracks only at 2 locations, and no crack appeared at the stress shield zone.
Pilot Study of Reliability Analysis of Damaged Piezoelectric Structure
Authors: Zhang Dan , Lu Xin Shui
Published: November 2010

According to the piezoelectric material damage theory and the fracture criterion based on damage theory, which has been established by Yang etc., reliability analysis is carried through about a damaged piezoelectric truss. Taken the mechanical damage extension force, electric damage extension force and cross-section area of bar element as stochastic variables, the expression of safety margins of bar element has been proposed. Based on those, the SFEM and PNET method are introduced to solve the reliability index of the structural system. The result indicates positive applied and negative applied electric field have great effect on the reliability of the system, which provides the basis to control the reliability of structural system. Finally, a calculation example is carried out under the conditions of positive applied electric field, negative applied electric field and no electric field. Meantime, the quantification results of the reliability index under three conditions are compared with each other.
Optimization for Cathodic Protection with Hierarchical Mesh Generation and Genetic Algorithm
Authors: Suga Kazuhiro , Murotani Kohei
Published: November 2010

This study presents an optimization technique with hierarchical mesh generation technique and genetic algorithm. The present technique is applied to optimize layout of electrodes on cathodic protection.
Finite Element Analysis of Fretting Fatigue Using Different Pad‘s Geometries and Compression Forces
Authors: Hojjati Talemi R. , Hojjati Talemi A. , Abdel Wahab Magd , de Baets Patrick
Published: November 2010

In this paper, a finite element sub-modelling method is used to estimate the stress distribution and the crack propagation lifetime in Aluminium alloy, Al7075-T6 specimens. Different contact geometries, i.e. cylinder-on-flat and flat-on-flat, and different contact span width’s with different pad’s compression forces are analysed. It is found that fretting fatigue life for two based cylindrical pads is shorter than that for two based flat pads and in two based flat pads is shorter than that for perfectly flat pads. In the case of two based flat pads, stress distribution in the pad with width of 3.1 mm is about 14% higher than that in the pad with the width of 6.2 mm and about 21% higher than that in the pad with the width of 9.3 mm. Similarly, stress in cylindrical pads with width of 3.1 mm is 36% higher than that in the pad with width of 6.2 mm and 130% higher than that in the pad with width of 9.3 mm. Stresses increased by 21% for pad force of 1800 N and around 40% for pad force 2400 N compared with 1200 N pad force. Also it is observed that by increasing pad width for both flat and cylindrical pads, crack propagation lifetime increased. Furthermore, fretting fatigue crack growth rate raises when pads compression force increases.
The Effect of Solid Solution Impurities on Dislocation Nucleation in a (001) Mo – 1.5 at.% Ir Single Crystal
Authors: Dub Sergey , Zasimchuk Igor , Matvienko Leonid
Published: November 2010

Mechanical properties of (001) Mo and (001) Mo – 1.5 at.% Ir single crystals have been studied by nanoindentation. It has been found that the iridium addition to molybdenum leads to an increase in both hardness and elastic modulus. An abrupt elasto-plastic transition (pop-in) at a depth of about 20 - 40 nm caused by dislocation nucleation in previously dislocation-free volume has been observed in the initial portion of the loading curve. It has shown that the Ir addition essentially affects the dislocation nucleation. Mean shear stress required for the dislocation nucleation increased from 10.8 GPa (G/12) for a Mo single crystal to 18.2 GPa (G/8) for the Mo – 1.5 at% Ir solid solution. Thus, the Ir solution in a Mo single crystal affects not only the resistance to the motion of dislocations (hardness) but the nucleation of them as well. The latter is likely to occur as a result of an increase in the structure perfection of the Mo – 1.5 at% Ir solid solution as compared to the pure Mo single crystal.
Hydrothermal Synthesis of Hexagonal Phase Zn1-XMnxS (x = 0–0.05) Nanorods Using Single-Source Precursors
Authors: Du Zhen Ni , Zhang Yong Cai , Xu Zhi You , Zhang Ming
Published: November 2010

The synthesis of hexagonal phase Zn1-xMnxS (x = 0–0.05) nanorods was achieved by hydrothermal treatment of zinc manganese diethyldithiocarbamates (Zn1-xMnx-(DDTC)2, x=0–0.05) in 40 mass % hydrate hydrazine aqueous solution at 180 °C for 12 h. The structure, composition and optical property of the obtained products were characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy and UV-vis diffuse reflectance spectra.
Low Temperature Sintering of (Ca0.9375Sr0.0625)0.25(Li0.5Sm0.5)0.75TiO3 Microwave Dielectric Ceramics
Authors: Li Yue Ming , Zhang Hua , Wang Zhu Mei , Hong Yan , Shen Zong Yang
Published: November 2010

The sintering behavior and microwave dielectric properties of the (Ca0.9375Sr0.0625)0.25(Li0.5Sm0.5)0.75TiO3 (CSLST) ceramics doped with different amounts of Li2O-B2O3-SiO2-CaO-Al2O3 (LBSCA) glass were investigated. The sintering temperature of the CSLST ceramics can be effectively reduced over 200oC due to the addition of LBSCA glass. For the 5 wt% LBSCA-doped CSLST ceramics, which are sintered at only 1000 oC for 5 h, show optimum microwave dielectric properties as follows: εr=84.74, Qf=2446 GHz and τf=-12.48 ppm/oC.
Electrochemically Deposited Aluminum in Template of Porous Silicon Film
Authors: Zhai Bao Gai , Ma Qing Lan , Meng Ming , Huang Yuan Ming
Published: November 2010

In this article, we report on the observations that in the aqueous electrolyte of aluminum nitrate, the thin metallic conducting films on both internal and external surface of porous silicon (PS) thin films that emit visible photoluminescence at room temperature prior to electrochemical deposition have been obtained under electrochemical deposition condition. Add to this high surface-to-volume ratio and these make it a good candidate for the catalyst supporter. We have investigated the surface morphology of PS after the interval of about 30 hours of electrochemically deposited aluminum by means of scanning electron microscopy (SEM). It has been shown from SEM images that not only micrometer-sized pores are smoothed by deposition of aluminum microcrystal, but also the presences of semi-sphere aluminum microcrystal which rooted in the tip of micrometer-sized pores are observed. On the one hand, this extremely interesting phenomenon which the micrometer-sized pores are smoothed may be explained in terms of principle of electrochemical deposition; on the other hand, we have laid the formation mechanism of semi-spherical aluminum microcrystal at the door of Gibbs free energy.
Transparent Conducting TGZO Thin Films Deposited by DC Magnetron Sputtering at Room Temperature
Authors: Liu Han Fa , Zhang Hua Fu
Published: November 2010

Transparent conducting Ti-Ga co-doped zinc oxide (TGZO) thin films with high transmittance, low resistivity were firstly prepared on glass substrate by direct current (DC) magnetron sputtering at room temperature. X-ray diffraction (XRD) and scanning electron microscopy (SEM) show that the TGZO films are polycrystalline with a hexagonal structure and have a preferred orientation along the c-axis perpendicular to the substrate. The lowest resistivity obtained in our experiment is 3.95×10-4Ω⋅cm. The average transmittance of the films is over 92% in the range of 400~760 nm.
Wet-Chemical Processing and Angle-Dependent Optical Properties Characterization of Mica/TiO2/Al2O3/M2O3 (M = Fe, Cr, Co) Pigments
Authors: Du Hai Yan , Liu Cai Xia , Sun Jia Yue
Published: November 2010

The four-layer structure angle-dependent pigments with compositions of Mica/TiO2 /Al2O3/Fe2O3, Mica/TiO2/Al2O3/Cr2O3 and Mica/TiO2/Al2O3/Co2O3 were firstly prepared by the wet-chemical coating method, respectively. The as-prepared pigments were performed by precipitating different metal ions, such as Cr3+, Fe3+, Co2+and Al3+, on the pretreated substrates, mica titanium. The optical effects of four-layer structure pigments were investigated in detail by using the five angles’ spectrophotometer. The angle-dependent spectral reflectance and color changes can be quantitatively measured, and the results show that the angle-dependent effects for the as-prepared pigment were improved by the increasing coated Al2O3 layers.
Microstructure and Wear Resistance of Laser Cladding of Ni-Based Alloy on Copper Substrate
Authors: Wang Yun Shan , Liu Neng Wen , Zhu Fu Dong
Published: November 2010

In order to improve the service life of copper crystallizer, a layer of Ni-based alloy on thick copperplate surface was performed by plasma spray process, and then YAG pulsed laser was used to remelt spray coating. Microstructure analysis, hardness test, and the wear resistance comparison experiments were taken to the specimen. The result shown that the Ni-based alloy cladding, metallurgy bonding with the copperplate, can be performed by taking the method of the YAG laser remelt technology; the structure of the cladding is compact, without defects such as pores and cracks. The micro hardness of cladding zone is between 450-490HV, which is much higher than that of the copper substrate (about 90 HV). The wear tests showed the laser cladding layer performed 14 times higher wear resistance compared to copper substrate.
Growth and Ferroelectric Properties of PZNT Single Crystals from High Temperature Solution
Authors: Xu Jia Yue , Shen Hui , Fan Shi Ji , Jin Min , Lu Bao Liang , Shi Min Li
Published: November 2010

The solid solution crystal Pb(Zn1/3Nb2/3)O3-PbTiO3 [PZNT] has been grown from the high temperature solution. The crystallization behavior of PZNT was investigated. The evaporation of PbO was controlled by sealing crucible and the erosion of the melt or solution on Pt crucible was discussed. By optimizing growth conditions, high quality PZNT crystal was obtained. The ferroelectric properties were measured and the results showed as–grown crystal has high performance.
Solvothermal Synthesis of CuInS2 Porous Microspheres
Authors: Hu Han Mei , Deng Chong Hai
Published: November 2010

The porous hierarchical spherical CuInS2 microsturctures have been successfully fabricated through one-pot solvothermal technique. The crystal structure and morphology of the as-synthesized products are characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM). The results reveal that the shells of CuInS2 microspheres are composed of nanosheets or nanoparticles. The possible formation mechanism of CuInS2 porous microspheres is simply discussed.
Nanocrystalline Silicon Films Grown at High Pressure in Very High Frequency Plasma Enhanced Chemical Vapor Deposition System
Authors: Guo Yan Qing , Huang Rui , Song Jie , Wang Xiang , Zhang Yi Xiong
Published: November 2010

Nanocrystalline silicon films have been fabricated from SiH4 diluted with H2 in very high frequency (40.68 MHz) plasma enhanced chemical vapor deposition system at low temperatures (250oC). The influence of pressure on the structural properties of nanocrystalline silicon films has been investigated. The experimental results reveal that a very high hydrogen dilution is needed to crystallize the film grown at high pressure. If the hydrogen dilution is not high enough, the film could also be crystallized through lowering the pressure. Furthermore, the crystallinity and grain size increase with decreasing the pressure. These results could be attributed to the increase of ion bombardment energy and the higher atomic hydrogen flux toward the growing film surface at lower pressures.
Study of the Dynamic Modulation Transfer Function of Modified Super-Wide-Angle Sagnac Imaging Interferometer
Authors: Tang Yuan He , Peng Tong , Qin Lin , Duan Xiao Dong , Qu Ou Yang , Cao Xian Gang , Jia Qi Jie
Published: November 2010

Modulation transfer function (MTF) is an important parameter for one image system. In order to obtain the more imaging quality performance of the modified super-wide-angle Sagnac imaging interferometer (MSASII) put forward by our group, and also have a qualitative analysis of its advantages and disadvantages in the process of application. Its dynamic MTF is focused on in this paper. The dynamic MTF expression of the MSASII is calculated. According to earlier research parameters of the MSASII, the dynamic MTF curve is described and corresponding corrective measures in theoretical is given. The result is demonstrated that the imaging quality of MSASII could satisfy the need of detecting upper atmospheric wind field.
A Novel Method for the Fabrication of Infrared Focal Plane Arrays Based on the Amorphous Silicon
Authors: Liu Huan , Liu Wei Guo , Cai Chang Long , Zhou Shun
Published: November 2010

A novel method for fabrication of self-supporting microbridge based on a-si films with tilted support legs for bolometer is studied in this paper. Based on the research of diffractive characteristics when the light passing through the mask in proximity lithography, we found if the distance of mask and photoresist is suitable, the intensity distribution curve of Fraunhofer diffraction (far field diffraction) at the border of contacthole is suitable to fabricate microbridge with tilted legs. By use of the method, the constant change of photoresist thickness around the contacthole can be realized using the far field diffraction proximity lithography. Then transfer the outline of photoresist to the sacrificial layer by plasma etching. Thus the fabrication of microbridge with tilted support legs was carried out easily, and this method has the advantages of low cost, simple and feasible.
Study on the Evolution of Surface Morphology of Hetero-Epitaxy Growth of ZnO Thin Film
Authors: Xiao Jing Zhong , Paixão José António Carvalho , Jia Quan Jie
Published: November 2010

Nano-granular ZnO thin films were deposited on Si (100) by molecular beam epitaxy (MBE) by varying growth time. The atomic force microscopy (AFM) and Raman scattering experiments were performed to study the surface morphology and vibrational properties of ZnO layer. The results show that the ZnO thin film grows in the Stranski-Kranstanow (SK) mode, and the critical thickness in our experimental condition is between 5.5 and 8.2 nm.
Properties of ZnO/Diamond Film Heterojunction
Authors: Xia Fu Yuan , Wang Lin Jun , Huang Jian , Tang Ke , Zhang Ji Jun , Shi Wei Min
Published: November 2010

High quality boron-doped p-type freestanding diamond (FSD) films with smooth nucleation surface were prepared by hot filament chemical vapor deposition (HFCVD) method. The effects of B/C ratios on the electrical properties of FSD films were investigated by Hall effect measurement system. N-type Al-doped ZnO films were prepared on p-type FSD films by radio-frequency (RF) magnetron sputtering method to fabricate heterojunction. The I-V characteristic of the heterojunction was examined. The results showed a rectifying behavior of this structure.
Growth of Undoped GaAs Single Crystal by Pulling-Down Method
Authors: Jin Min , Xu Jia Yue , He Qing Bo , Fang Yong Zheng , Shen Hui , Wang Zhan Yong , Jiang Guo Jian
Published: November 2010

Undoped GaAs single crystal has been grown in PBN crucibles by the pulling-down method. The temperature profile of the furnace was optimized with a narrow melting zone and a small temperature gradient at the solid-liquid interface. Quartz ampoules were used to protect the evaporation of As during the growth and the deformation of the ampoule was discussed as a function of temperature, time and pressure differential. A Ø56 mm×70 mm GaAs crystal with nearly 100 % single crystalline yield was obtained. X-ray rocking curve analysis revealed the excellent crystalline quality. The average EPD and electrical properties of the crystal were tested comparable to those of the crystal produced by the VGF method. Therefore, the pulling down method was a feasible approach for GaAs crystal production.
Structure and Electrochemical Performance of Amorphous Nickel Hydroxide Doped with La and Al
Authors: Liu Chang Jiu , Xing Chun Xiao , Chen Shi Juan , Li Yan Wei
Published: November 2010

Amorphous nickel hydroxide powders doped with rare earth La3+ and Al3+ were synthesized by the combined chemical precipitation and rapid freezing method. The microstructure of the samples was characterized by XRD and Raman spectra. The electrochemical performance of the prepared samples was analyzed by electrochemical impedance spectroscopy and charge-discharge tests. The results showed that this amorphous nickel hydroxide codoped with La3+ and Al3+ had more structural defects than those of the undoped amorphous nickel hydroxide and La3+ singly doped amorphous nickel hydroxide. These abundant structural defects with La3+ and Al3+ codoped amorphous nickel hydroxide decreased the electrochemical impedance spectroscopy and improved the electrochemical reversibility of the amorphous nickel hydroxide electrode.
Structure and Low Melting Property of Vanadate Tellurite Glass
Authors: Luo Shi Yong , Xu Wen Cai , Zhang Xin Lin , Huo Li Xia
Published: November 2010

The glasses (80-x)TeO2·xV2O5·20MO (M=Sn, Bi, Ca, Na and K) had been examined as potential replacements for PbO-based glass frits with low firing temperature. The glasses with TeO2 0-44 mol%, and V2O5 39-82 mol% are not suitable for glass frit since they are easy to crystallize. The glasses with the content of the TeO2 54-74 mol%, and the V2O5 9-29 mol% were investigated by differential scanning calorimetry, X-ray diffraction, infrared spectra and fluidity evaluation experiments. The glasses possess appropriate fluidity and do not crystallize in the re-melting process at 723-753 K. The glass transition temperature of the glasses is at 544-578 K. The structure of the glasses is layer upon layer mainly connected by the structure units of [VO4] and [TeO3]. Other modifier ions locate mainly between the layers. The isolated V=O band from the VO5 bipyramids is not occurred in the vitreous structure of the glasses.