bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of Artificial Structural Loess under the True Triaxial Tests
Authors: Chen Chang Lu , Juan Fang , Luo Ai Zhong , Shao Sheng Jun
Published: March 2013

Structure characteristic is the essential property of natural soils. The paper developed an indoor method of artificial structural loess, and studied on the true triaxial tests of artificial structural loess on the base of improving the original true triaxial apparatus. The results show that it is reasonably reliable of this artificial method. At the same time, the variation of failure strength and residual strength of structural loess under complex stress conditions was analysised. When the confining pressure was less than the structural strength of the structural loess, the stress-strain curve was soften, on the contrary the stress-strain curve was harden. In the end the paper analyzed that Mohr-Coulomb strength criterion was accurately to describe the residual strength variation of structural loess but there has much error in describing the peak broken strength, the value was obviously small.
Genetic Analysis and Treatment of Cracks in the Residential Construction
Authors: Liu Hao , Du Xiao Ming
Published: March 2013

In the modern construction process, the wall cracks in residential buildings in the more general question, which the concrete cracks. Concrete cracks caused by a variety of reasons, such as temperature changes, uneven ground subsidence, wall expansion and contraction, there are some cracks by external effects or conservation measures is wrong or some chemical reaction causing the problem. In this paper, architectural design, building materials, construction and other aspects to analyze and propose some solutions approach.
Flac3D Numerical Simulation Study on the Failure Developing Law of Interface for Geotechnical Prestressed Anchorage Bolt
Authors: Zhang Si Feng , Feng Jian Xiang , Han Rui
Published: March 2013

One of the main failure forms of inner bond section for prestressed anchorage structure is the failure of interface between the rock mass and the grouting body, so this interface is usually one of the weak link of the whole anchorage system, and so it is important to analyze the failure developing law of the interface. Based on the finite difference program FLAC3D, the numerical analysis model of inner bond section for prestressed anchorage bolt was built, and the failure developing laws of inner bond section under step loading were studied from three aspects: displacement change, shear stress change and yield point position change. The influence of the change of inner bond section length and the grouting body strength on the inner bond section failure developing law was also analyzed. At last, compared with the results of indoor static load test, the reliability of the numerical simulation was certified.
Nonlinear Solution Formulation for Complex Space Truss
Authors: Fu Chao Jiang
Published: March 2013

A new geometric nonlinear formulation for large-deflection static problems involving complex space truss structure is presented. Based on the finite element method, the proposed formulation uses nodal positions rather than nodal displacements to describe the problem. The strain is determined directly from the proposed position concept, using a Cartesian coordinate system fixed in space. The proposed formulation is simple and yields good results. Numerical results indicate that the proposed formulation is validity.
Numerical Analysis of Bearing Capacity to Q690 Tubular Joints Enhanced by Tile Shaped Plate
Authors: Han Xuan Min , Peng Yi Liang , Li Hong Bo , Zhang Tao
Published: March 2013

Simple joint is a common connection in tubular structures. Local buckling occurs in panel zone when the joints bear heavy loads, and local buckling will reduce the bearing capacity and stiffness. In order to improve the bearing capacity of tubular joints, the joints need to be strengthened. In this paper, the bending performance of the joints will be enhanced by welding a tile shaped plate outside the surface of panel zone of chord member. By ANSYS finite element program, the bearing capacity of the joint with different tile shaped plate was analyzed. The results showed that the bearing capacity of the joints experience obvious change with variation of thickness, whereas the bearing capacity has no change with variation of radian.
Numerical Simulation on the Dynamic Response of Buried Pipelines Subjected to Blast Loads
Authors: Xu Guo Fu , Deng Zheng Dong , Deng Fei Fan , Liu Guo Bin
Published: March 2013

When the shock wave caused by explosion in geotechnical medium encountered buried pipeline, the buried pipeline may be destroyed. Use the LS-DYNA program to describe the deformation of buried pipelines under explosion ground shock. The results indicate that the process of the stress on pipe is instantaneous, and the back of buried pipelines against explosion center suffers greater instantaneous pulling stress in axis direction. The stress on the pipes, which is brought by the weaponary explosion, is involved with the distance between the pipe and explosion center and the diameter of pipe, among which the former involves greater. And the smaller pipe would get greater shock.
Research on the Connection Modes and Numerical Simulation Methods of RC Frame and Infill Wall
Authors: Jin Huan
Published: March 2013

In the evaluation of the seismic performance of masonry-infilled RC frames, the main difficulty is determining the type of interaction between the infill and the frame, which has a major impact on the structural behavior and load-resisting mechanism. This paper addresses the connection modes of the RC frames and masonry panels in regulations in China. The method of flexible connection suggested in standard has not been widely used in actual engineering, and rigid connection was adopted in universal. The finite element model with interface element is advisable for simulating the interaction of the frames and panels, and the accuracy of the nonlinear finite-element models has been evaluated with experimental data. The comparison of the numerical and experimental results indicates that the models can successfully capture the highly nonlinear behavior of the physical specimens and accurately predict their strength and failure mechanisms.
Stationary Problems of Moisture-Elasticity for Inhomogeneous Thick-Walled Shells
Authors: Andreev Vladimir I. , Avershyev Anatoliy S.
Published: March 2013

This paper contains a solution of the problem of determining stress state in clay soil near a cylindrical and spherical cavities for the propagation of the moisture out of the cavity into the solid mass. The problem is solved in a stationary symmetric formulation taking into account changes the modulus of elasticity of soil moisture. The problem is reduced to a differential equation with variable coefficients. This complicates the solution of the problem compared with the solutions for constant modulus of elasticity, but it provides a more accurate solution.
The Nonlinear Finite Element Analysis to Bonded Post-Tensioned Prestressed Concrete Frame Based on Two-Stage Loading Model
Authors: Chen Ming Zheng , Huang Lin Qing , Chen Xiao Ying , Wang Li Ping
Published: March 2013

According to the loading character of bonded post-tensioned prestressed concrete frame, the static nonlinear finite programme in this paper could be used to analysis the whole loading process to bonded post-tensioned prestressed concrete frame, which is divided into two different stages . From the stress-strain curve of materials and considering the concrete’ tension harding and compression softening, this programme uses the layered finite element model and arc-length method to analyse the bonded post-tensioned prestressed concrete frame, during the course it considers the material nonlinearity and geometric nonlinearity in the stiffness matrix. Through the contrast to experiment , the result of the programme fits well with the experiment. The programme can be used to compute and analyse the bonded post-tensioned prestressed concrete frame.
Landslide Machanism in Xinghai Zhong Long Yuan and Its Reinforcement Technology
Authors: Li Jin Kui , Sun Hua Zhong , Li Xia
Published: March 2013

The landslide is a global geological disasters, causing casualties and huge economic losses. This paper, the Dalian Xinghai Zhong Long Yuan landslides treatment project, analysis of landslides generated by internal causes and predisposing factors, obtained a landslide failure mechanism, and the causes of slope cutting, improve cut flood drainage structures, prestressed anchor Mississauga solid technical measures. The construction process for top of the hill horizontal displacement, deep horizontal displacement and anchor bearing capacity monitoring results show that the landslide control program is correct and effective measures to achieve the desired effect, made landslides governance success to reference for landslide control work for the Dalian region and the coastal cities.
Measurement and the Distribution Law of In Situ Stresses at Deep Depth of Hongyang Coal Mine
Authors: Xia Hong Man , Wang Jiong , Liu Yang , Pang Jie Wen , Liu Dong Qiao , Ren Xiao Long
Published: March 2013

There are many in situ stress measurement methods nowadays, the ISRM suggested two methods for in situ stresses measurement: overcoring methods and the hydraulic fracturing methods. In order to study the distribution law of in situ stress field in the deep position of Hongyang coal mine, 3 points of in situ stress measurement were carried out in underground roadways at the -870 m level adopting the overcoring method. The KX-81 type gauge was used to measure the 3 points of in-situ stress. According to the analysis and calculation of the measurement data, the result showed that the in situ stress field in Hongyang coal mine at the depth of -870m was dominated by horizontal tectonic stress.
Experimental Study on Improving Seismic Performance of Load-Bearing Masonry Walls Made of Autoclaved Aerated Concrete
Authors: Yu Jing Hai , Cao Jian Feng , Fei Tian Hui
Published: March 2013

Experiments of a piece of comparable block wall and five pieces of block walls with different constructional type subjected to low reversed cyclic loading have been conducted. Investigation has been made on the failure pattern, hysteretic loop curves, displacement-restoring capacity and displacement ductility of walls. The experimental results revealed that the seismic performance of block masonry walls, which used the constructional column and concrete strips, was improved remarkably. It set a sound basis for further analysis research and engineering practice on AAC load-bearing walls in the future.
Finite Element Analysis of Historical Construction with Differential Settlement
Authors: Liu Chun Yuan , Han Xiao , Liu Yu
Published: March 2013

Accompanied by masonry uniformly qualitative theory, the analysis was made for the influence on existing brick building with numerical simulation method. The stress and its distribution in the structure with differential settlement were calculated. Pointing out the parts with high stress, the work provides analytical reference to state assessment of existing buildings.
Monitoring and Numerical Simulation of the Supporting of the Inverted Side Wall Shaft
Authors: Yao Ai Jun , Mei Chao , Chen Huan Fang
Published: March 2013

Base on the shaft construction of a subway station in Changchun, make a detailed analysis of the site monitoring data of the retaining structure and the ground surface settlement against the excavation process of the inverted side wall shaft. By using the FLAC-3D software of finite difference, the numerical simulation are conducted, thus, make a comparison with the site monitoring data, and summarize the deformation characteristics of the retaining structure and the surface deformation of the inverted side wall shaft during the excavation. Results show that the support of the inverted side wall shaft which adopting alternation excavation and supporting while excavating has good stability, and the monitoring result is close to the numerical simulation’s, which provides the basis for the success of the engineering.The research results can be references for other similar designs and constructions.
Influence of Reinforcement Ratio to the Ductile Property in Prestressed Concrete Hollow Slab
Authors: Han Dong , Cui Xiu Qin , Wu Rong , Lv Shi Ge
Published: March 2013

The numerical analysis method is applied to simulate the whole process of bending. Keeping the section dimensions and the types of loads constant in prestressed concrete hollow slab with mid-strength spiral-rib steel wire, strength of concrete, strength of steel bar, reinforcement ratio, span-depth ratio and stretching control stress are analyzed and compared. The influence of reinforcement ratio to the ductile property in prestressed concrete hollow slab is discussed by numerical simulation.
Performance of Different Corrosion Ratio RC Beams under Fatigue Load
Authors: Yu Ai Ping , Lu Hai Bo , Zhao Yan Lin
Published: March 2013

For investigating the stiffness changes on reinforced concrete beam at different level of corrosion after fatigue, a group of RC beams were designed with different corrosion ratio, and fatigue test was carried on these specimens. The deflection, strain and crack of these specimens were analyzed in fatigue loading. The results indicate that the effect of corrosion ratio on fatigue performance of RC beams is very obviously.
Probabilistic Model of Corrosion in Reinforced Concrete Structures Considering Coupling Effects of Influence Factors
Authors: Zhang Xiao Gang , Wang Jiao
Published: March 2013

A probabilistic model of the chloride-induced corrosion process is provided in this paper. Based on the Third-moment method, the uncertainty of various influence factors and the coupling effects of them are concerned. Considering the corrosion process as a statistic process, the probability of corrosion initiation at certain time can be obtained. Moreover, the effect of micro-crack in chloride ingress is taken into account, too. Due to the results of stochastic analysis, the surface chloride concentration is the most important factor that affects the corrosion probability, while the thickness of concrete cover, chloride diffusion coefficient, environmental relative humidity, critical threshold chloride concentration, micro-crack rate, water-to-cement ratio and temperature are also important factors. And the Third-moment method is proved to be reasonable in the durability assessment of corrosion-induced concrete structure. The results in this paper can be used to predict the rest life of corrosion-induced concrete structures.
Strengthening Research in the Longitudinal Frames of Prefabricated Structures with Viscous Dampers
Authors: He Bin , Pang Jin Lai , Liu Cheng Qing
Published: March 2013

For the lack of research in the longitudinal frame of prefabricated structure for its weak lateral stiffness, pushover analysis is conducted to evaluate the seismic performance of a fabricated concrete frame. Based on case study, the strengthening strategies with viscous dampers are analyzed. In view of the undesirable drift distribution and failure mode in the existing building, it is believed that arrangement of dampers should be designed to attain a uniform drift distribution. Based on the nonlinear time history analysis method, the strategy of damper allocation in vertical direction of the structure is investigated .Results indicate that a proper design might be attained based on the property of existing system, leading to a uniform drift distribution and better seismic performance.
The Study on Static Force Behavior of Concrete Filled Steel Tube Lattice Wind Generator Tower Joints
Authors: Wen Yang , Zhou Fei
Published: March 2013

In order to discuss the failure mechanism of concrete filled steel tube lattice wind generator tower joints. Based on the parameters of web member section form, and using nonlinear static numerical simulation, this dissertation research on the stressed complex joints. The results of the study show that the abdominal rod for circular steel tubes joint (JD1) is instability failure which is led to the local buckling of compressive bar; the abdominal rod for single angle steel (JD2) or double angle steel (JD3) joint is instability failure because of the local buckling of the joint board. Under the web members and joint boards all fitting their own capacity requirements, JD1 is very easy to make draw bar broken on both sides of the pillar tube wall region, JD2 and JD3 are apt to damage on the weak positions of joint board ends and pillar tube wall joint. In the three forms of web member joints, the best ultimate bearing capacity is JD1 , JD3 is the second and JD2 is minimum.
Numerical Analysis on Bending Strength and Ductility of Compact Section I-Girders with HSB800 Steels
Authors: Choi Byung H. , Park Yong Myung
Published: March 2013

New high performance steel HSB800 have been developed in South Korea, the yield strength of which is equal to 690MPa. High strength steels typically show a lower ductility and a larger yield ratio than conventional steels. Since the inelastic design procedure of current AASHTO specifications is not permitted to the flanges and webs of nominal yield stress exceeding 485 MPa, this study is intended to present an assessment result of the compactness requirements for I-section girders by performing 3D nonlinear finite element analyses. On the hypothetical specimens designed to be compact-section girders, the numerical analysis was performed using the finite element code ABAQUS. From the analysis results, it is found that the compact section limits speculated in the 2007 AASHTO LRFD could be applicable to the design of HSB800 steel I-girders to reach the plastic moment. However, the inelastic design procedure does not surely confirm a sufficient flexural ductility. More extensive studies of HSB800 I-girders are still in need.
Finite Element Analysis on the Resistance Capability of a New Precast Concrete Tube Column
Authors: Ding Hong Yan , Nie Jing Hu , Zhang Pu Yang , He Chao
Published: March 2013

A new type of composite structure, precast concrete tube column is proposed, and its axial compression performance and the seismic performance of beam-column joint are studied. Nine groups of precast concrete tube column models and three groups of common solid column contrast models with the same outer diameters (600,800,1000mm) were established by software ABAQUS, and a beam-column joint model for horizontal low cyclic loading was established combining with practical project. The results show that the ultimate bearing capacity of precast concrete tube column is higher than that of the common solid column with the same outer diameter by 5% to 20%, and it increases slightly as the thickness of tube increases. Displacement - load hysteresis curve of the beam-column joint is relatively full under cyclic load, and the slope of skeleton curve decreases slowly, which provides an important basis for engineering applications.
Study on the Dynamic Behavior of Semi-Rigid Frames
Authors: Sun Xiu Li
Published: March 2013

The dynamic behavior of semi-rigid concrete filled steel tube frames is different from that of their rigid counterparts. ANSYS was employed to model ten-story concrete filled steel tube frames with three different connection types（ rigid, semi-rigid and flexible）. Natural period, inter-story drifts and total drifts of the frames subjected to design response spectra excitation were analyzed. Time-history analyses when the frames subjected to two different earthquakes were studied. It seems that connection flexibility noticeably increases the natural periods of the lower modes, however, its effect on higher modes is negligible. The use of rigid frames may not be the best option in seismic region. The seismic design suggestions of the frames were proposed.
The Research of the Slewing Bearing Force Balance of the Super Large Lifting Equipment
Authors: Guo Ji Tan , Li Song Feng
Published: March 2013

The slewing bearing of the full-revolving super large lifting equipment bears all loads above the rotating platform. Due to the effect of bending moment, the load conditions of the slewing bearing structure is complex and large, which leads to the non-uniform of stress and uneven deformation and final seriously affects the work performance of lifting equipment. The numerical example in this paper considers three kinds of sliding-friction models between slewing bearing structure and orbit. By numerical analysis results, we adjusted the structure arrangement and stiffness distribution. Finally the non-uniform of stress of the slewing bearing structure has been improved and tended to be uniform. Thus the paper presents a new approach for the design of the slewing bearing in super large lifting equipment.
Dynamic Characteristics of a Wood Frame Structure: (I) the Effect of Temperature and Relative Humidity
Authors: Yao Dong Sheng , Xing Hai Ling , Xue Song Tao
Published: March 2013

A full-scale, three-storey, light timber frame of a residential house was tested in-situ to investigate the effect of structural damage, temperature and relative humidity changes on its natural frequency. As expected, test results provide the evidence of the significant influence that temperature and relative humidity changes have on the natural frequency of the test structure. Regression analysis of the test results revealed that the natural frequency change of the structure is generally in a linear relationship with the variation of both relative humidity and temperature. Furthermore, variation of natural frequency induced by relative humidity and temperature may be much stronger than that induced by damage of structural members. It is concluded and recommended that the effect of temperature and relative humidity change should be considered when the natural frequency is used as an indicator for damage identification of timber constructions.
Microstructure and Mechanical Properties of Directionally Solidified Unmodified and Ni-Modified Sn-0.7wt%Cu Lead-Free Solder Alloy
Authors: Cheung Noé , Garcia Amauri , Spinelli José Eduardo
Published: March 2013

Lead containing solders (SnPb eutectic alloys) are widely used in electronic devices due to their good mechanical properties and low manufacturing cost. However, two European Union regulations (Waste from Electrical and Electronic Equipment and Restriction of Hazardous Substances) banned the use of lead in electrical and electronic equipment because of the toxic effect on human health and the environment. Nowadays, it is particularly important to find replacements for Pb containing solder materials. In that respect, copper is used as an alloying element and the composition Sn-0.7wt%Cu is of particular interest. Small Ni additions can be interesting since they would be included into the composition of the commercial solder SN100 and can also avoid the presence of coarse and deleterious Cu6Sn5 particles for Sn-Cu alloys in the hypoeutectic range of compositions. In the present investigation, growth rate, cooling rate, interfacial heat transfer coefficient (hi), the scale of the microstructure and morphologies, ultimate tensile strength and elongation have been experimentally determined for Sn-0.7wt%Cu and Sn-0.7wt%Cu-0.1wt%Ni alloys solidified in a water-cooled vertical upward unidirectional solidification system. Further, interrelations of thermal parameters, microstructure and tensile properties may be established. A higher time-dependent hi profile was found for the Sn-0.7wt%Cu-0.1wt%Ni alloy which seems to indicate that a higher fluidity was obtained with small Ni addition. Higher fluidity values may characterize better physicochemical affinity between the melt and the mould surface. The modified Sn-Cu alloy propitiates higher ultimate tensile strength values to be obtained. This may be due to the prevalence of eutectic two-phase cells along the casting associated with fine Cu-rich particles close to the water-cooled surface.
Mössbauer Spectroscopy of Internal Interfaces in Metals
Authors: Popov Vladimir V.
Published: March 2013

A brief review on various possibilities of studying internal interfaces in metals by various methods of Mössbauer (nuclear gamma-resonance) spectroscopy is presented. Specific features of investigations of different interfaces in various materials are considered, such as equilibrium boundaries of recrystallization origin in coarse-grained materials, non-equilibrium boundaries in submicro-and nanocrystalline materials and interlayer boundaries in multilayered structures.
Li Diffusion in (110) Oriented LiNbO3 Single Crystals
Authors: Rahn Johanna , Dörrer Lars , Ruprecht Benjamin , Heitjans Paul , Schmidt Harald
Published: March 2013

Li diffusion is investigated in Li2O-deficient, (110) oriented LiNbO3single crystals in the temperature range between 523 and 673 K by secondary ion mass spectrometry. A thin layer of ion-beam sputtered isotope enriched6LiNbO3was used as a tracer source, which allows one to study pure isotope interdiffusion. The diffusivities coincide with those of (001) oriented single crystals and follow the Arrhenius law with an activation enthalpy of 1.33 eV. The results prove the existence of a three-dimensional diffusion mechanism.
Calculating of Diffusion Profiles in Ternary Systems Using Effective Interdiffusion Coefficients of Components
Authors: Ugaste Ü. , Priimets J.
Published: March 2013

A method has been developed for calculating diffusion profiles in ternary systems by using effective interdiffusion coefficients of components and Boltzmanns solution for diffusion equation with variable diffusion coefficient. Using this method the concentration profiles for several diffusion couples in the systems Fe-Co-Ni and Cu-Fe-Ni are calculated as examples and some peculiarities of these calculations are discussed, particularly, how to solve some possible difficulties, which may sometimes arise at calculation procedures. It is shown that having the data on effective interdiffusion coefficients and their concentration dependence for at least two components in a ternary diffusion couple, the concentration profiles for all three components can be calculated with good accuracy.
Fabrication of 30-nm-Pitched CoPt Magnetic Dot Arrays Using 30-keV-Electron Beam Lithography and Ion Milling for Patterned Media
Authors: bin Mohamad Zulfakri , Alip Rosalena Irma , Komori Takuya , Akahane Takashi , Zhang Hui , Huda Miftakhul , Yin You , Hosaka Sumio
Published: March 2013

CoPt magnetic dot arrays with a fine pitch of 30 nm have been fabricated using electron beam (EB) lithography and ion milling. The possibility to ion-mill CoPt film using EB drawn calixarene resist pattern as a mask has been studied. We formed 30 nm pitch resist dot arrays with a dot diameter of 20 nm using 30-keV-EB lithography with calixarene resist. The resist dot arrays were ion-milled for 4 min using 200-eV Ar ion milling to fabricate CoPt dot arrays on a Si substrate. We fabricated fine pitched CoPt magnetic dot arrays with a diameter of 22-35 nm and a pitch of 30-150 nm. Results show that the ion-milled CoPt dot diameter increased with the dot pitch while the resist dot had a similar diameter of 20 nm.
Piezoresistive Acceleration Sensor with High Sensitivity and High Responsiveness
Authors: Kurokami Shintaro , bin Mohamad Zulfakri , Yin You , Hosaka Sumio , Fuju Takahiro , Sueyoshi Yoshiharu , Okano Haruki
Published: March 2013

In this work, a new-type piezo-resistive acceleration sensor with a slit in the beams is proposed to improve sensitivity by reducing the twisting of the beams. Experimental results demonstrated that the new-type acceleration sensor has about 3.5 times higher than that of the conventional acceleration sensor without the slit. Furthermore, resonant frequency of the new-type sensor increases to about 5 kHz by a factor of 25, compared with commercial acceleration sensor.
The Parameterization of All Plants Stabilized by a PID Controller
Authors: Hagiwara Takaaki , Yamada Kou , Hoang An Chinh , Aoyama Satoshi
Published: March 2013

In this paper, we examine the parameterization of all plants that can be stabilizedby a Proportional–Integral–Derivative (PID) controller. The PID controller structure is themost widely used controller structure in industrial applications. Recently, if stabilizing PIDcontrollers for the plant exist, the parameterization of all stabilizing PID controllers was considered.However, the parameterization of all plants that can be stabilized by a PID controllerhas not been examined. In this paper, we clarify this question. In addition, we present theparameterization of all stabilizing PID controllers for plants that can be stabilized by a PIDcontroller.
A 2nd-Order PWM Pre-Emphasis Technique and its Experimental FPGA Implementation
Authors: Yuminaka Yasushi , Ishida Shingo , Henmi Kenichi
Published: March 2013

In this paper, a Pulse-Width Modulation (PWM) pre-emphasis technique is extended to a2nd-order version to equalize a higher-order transfer function of an interconnection inside/betweenVLSI chips. The PWM pre-emphasis method does not change the pulse amplitude as for conventionalFIR pre-emphasis, but instead exploits timing resolution. As a proof of concept, a 2nd-order timedomainpre-emphasis technique is designed and implemented using an FPGA to demonstrate thecapability of compensating for deterioration of signals caused by interconnections with higher-ordertransfer functions.
Fabrication of Hole-Type Microcantilevers Using FIB and its Evaluations
Authors: Truong Anh Hoang , Sone Hayato , Kawakami Tomoyuki , Hosaka Sumio
Published: March 2013

A high sensitive mass biosensor using a piezoresistive hole-type microcantilever has been developed. To optimize the cantilever shape for high sensitivity easily, we demonstrate frame-type cantilevers with holes on the surface fabricated by Focused Ion Beam (FIB) method and evaluate their sensitivity in both air and liquid. Resonance frequency of hole-type cantilevers increased about 20% and 40% in air and in water, respectively. On the other hand, while Q value decreased from 10% to 30% in air, it increased sharply from 0% to 50% in water with increasing of hole-size. Especially, when we increased the frame size from 0.5 µm to 2.5 µm, resonance frequency changing and Q value changing in water were 60% and 125%, respectively. However, the Q value of large hole (36x60µm2) in water inversely decreased due to the decline in rigidity. The sensitivity of hole-type cantilever of Δm/Δf(hole-size = 12x12μm2; frame-size = 2.5μm) was 23.1 fg/Hz, 10 times smaller than the conventional type cantilever.
Vapor-Liquid-Solid Growth of Silicon-Based Nanowires for High Sensitive Sensor
Authors: Sone Hayato , Suda Yasuyuki , Kubota Daiki , Hosaka Sumio
Published: March 2013

Silicon-based nanowires (Si-NWs) were fabricated by vapor liquid solid (VLS) growth, and Si-NW device was prototyped using focused ion beam (FIB) processing. The needle shaped thin Si-NWs were formed at a substrate temperature between 1120 and 1313°C. The average and minimum diameters of the NWs were confirmed 60 nm and 44 nm, respectively. As the double-layered structure was observed in the NWs by transmission electron microscope images, it is possible that those are silicon-based NWs with Si core and SiO2shell structure. From current-voltage characteristics, the Si-NW device has a semiconducting property, and the estimated resistivity of the Si-NW is about 3.1 x 104Ωcm.
Preparation of Crystalline Turbostratic Boron Nitride Nanoparticles by Combination of Precursor Compound Formation and Impurity Segregation from Boric Acid and Urea
Authors: Kakiage Masaki , Yoshikoshi Daisuke , Yanase Ikuo , Kobayashi Hidehiko
Published: March 2013

Crystalline turbostratic boron nitride (t-BN) was prepared by a combination of precursor compound formation and impurity segregation from boric acid (H3BO3) and urea. A mixed material was prepared by separately dissolving H3BO3and urea in distilled water then blended them, which was followed by drying. A precursor compound including oxygen was formed from the mixed material upon low-temperature heat treatment at 250 °C. The oxygen-containing impurity was segregated as a boron oxide component by the hydrolysis of the precursor compound during the grinding process in air, leading to the effective layered structure formation and layer stacking of t-BN. Crystalline t-BN nanoparticles with well-stacked layered structures were prepared by leaching the segregated impurity in a hot aqueous solution of the product formed by heat treatment at 1300 °C in an Ar flow.
Effects of Interface Roughness and Lattice Strain on Perpendicular Magnetic Anisotropy in Co/Pd Multilayer
Authors: Go Naoto , Suzuki Kosuke , Emoto Shun , Itou Masayoshi , Sakurai Yoshiharu , Sakurai Hiroshi
Published: March 2013

The effects of strain and interface roughness at the Co/Pd interface are investigated from the viewpoint of perpendicular magnetic anisotropy (PMA) using the DV-Xα cluster model calculation method. It is found that spin projected occupation number ratio of magnetic quantum number |m| = 2 for the Co 3d electrons enhances by expanding the lattice within a close-packed plane of fcc stacking and, hence, enhances the PMA. Rough interface decreases the spin projected occupation number ratio of |m| = 2 and, hence, decreases the PMA. These results explain the PMA properties of Co/Pd multilayers fabricated using molecular beam epitaxy (MBE) technique and RF sputtering techniques.
Effect of Blending Asymmetry for Poly(L-Lactic Acid)/Poly(D-Lactic Acid) on Structural Change during Heating
Authors: Yokoyama Yuka , Uehara Hiroki , Yamanobe Takeshi
Published: March 2013

Stereo-complex (Sc) crystallinity and corresponding melting characteristics of poly (L-lactic acid)/poly (D-lactic acid) blend films depend on blending asymmetry. Two different mechanisms for Sc-crystallization are observed in this study. The symmetrical blend of PLLA/PDLA=50/50 gives a combination of α-form melting and subsequent Sc-crystallization during heating. In contrast, the asymmetrical blend of 75/25 film exhibits solid transformation from α-form into Sc-form due to molecular slippage without melting.
Effect of Metal Modification to Carbon Paper Anodes on the Performance of Yeast-Based Microbial Fuel Cells Part ΙΙ: In the Case with Exogenous Mediator, Methylene Blue
Authors: Kasem Enas Taha , Tsujiguchi Takuya , Nakagawa Nobuyoshi
Published: March 2013

Effect of metal modification to carbon paper as the anode of mediator-aided yeast-based microbial fuel cell on the cell performance was investigated using methylene blue as an exogenous mediator. The modification was conducted using a sputtering technique by depositing Co or Au thin layer, 30 nm. The electrode performance was evaluated by measuring the electrode potentials and the fuel cell power output. The metal modification significantly increased the mediator-aided MFC performance.
Constitutive Equations of Stress-Strain Responses of Aluminum Sheet under Stress Path Changes
Authors: Uemori Takeshi , Sumikawa Satoshi , Tamura Shohei , Yoshida Fusahito
Published: March 2013

Aluminum sheet metals have been widely utilized for a light weight construction of automobile. However, these metals still remain one of the difficult materials to predict the accurate final shapes after press forming processes, because of several mechanical weak features such as strong plastic anisotropy of yield stress, large Lankford value, and so on. In order to solve the problems, the present author has developed a new constitutive model. The model can describe accurate non-proportional hardening behaviors of an aluminum sheet metal. In the present research, several experimental procedures were carried out to reveal the mechanical properties of an aluminum sheet under proportional and non-proportional loading. From the comparisons between experimental data and the corresponding calculated results by the proposed constitutive model, the performance of our model was evaluated. The evaluation of some springback analyses were also carried out. The calculated results show good agreements with the corresponding experimental data.
Material Behaviors of PBX Simulant with Various Strain Rates
Authors: Park Chung Hee , Jeong Seh Wan , Huh Hoon , Park Jung Su
Published: March 2013

This paper is concerned with the material behaviors of PBX(Polymer Bonded eXplosive) simulant at various strain rates ranging from 0.0001/sec to 3150/sec. Material behaviors of PBX at the high strain rates are important in the prediction of deformation modes of PBX in a warhead which undergoes severe impact loading. Inert PBX stimulant which has analogous material behaviors with PBX was utilized for material tests due to safety issues. Uniaxial compressive tests at quasi-static and intermediate strain rates were conducted with cylindrical specimen using a dynamic materials testing machine, INSTRON 8801. Uniaxial compressive tests at high strain rates ranging from 1200/sec to 3150/sec were conducted using a split Hopkinson pressure bar. Deformation behaviors were investigated using captured images obtained from a high-speed camera. The strain hardening behaviors of PBX simulant were formulated by proposed strain rate-dependent strain hardening model.
Dynamic Hardening Equation of Nickel-Based Superalloy Inconel 718
Authors: Ahn Kwanghyun , Huh Hoon
Published: March 2013

The dynamic response of the turbine blade materials is indispensable for analysis of erosions of turbine blades as a result of impulsive loading associated with gas flow. This paper is concerned with the dynamic hardening equation of the Nickel-based superalloy Inconel 718 which is widely used in the high speed turbine blade. Reported representative dynamic hardening equations have been constructed and evaluated using the dynamic hardening characteristics of the Inconel 718. Dynamic hardening characteristics of the Inconel 718 have been obtained by uniaxial tensile tests and SHPB tests. Uniaxial tensile tests have been performed with the variation of the strain rate from 0.001/sec to 100/sec and SHPB tests have been conducted at the strain rate ranging up to 4000/sec. Several existing models have been constructed and evaluated for Johnson-Cook model, Zerilli-Armstrong model, Preston-Tonks-Wallace model, modified Johnson-Cook model, and modified Khan-Huang model using test results at various strain rate conditions. The most applicable equation for the Inconel 718 has been suggested by comparison of constructed results.
Comparison Investigation of Tensile Fracture Properties of Al Alloy at Different Dynamic Loadings
Authors: Lu Fang Yun , Wang Xiao Feng , Chen Rong , Li Xiang Yu , Zhang Duo , Lin Yu Liang , Zhou Chao Yang , Wu Shi Yong
Published: March 2013

Spall Strength, uniaxial tensile strength and fracture toughness, are three typical parameters describing the fracture properties of materials subjected to different loadings. Actually, these three macroscopically parameters are connected to the tensile fracture (Model I) properties, and many papers have been trying to find the intrinsic connection between each other. In this work, ZL205A aluminum is conducted by varies experiments: the spallation test loaded by a light gas gun, the dynamic uniaxial tensile test using the Split Hopkinson Tensile Bars (SHTB), and the dynamic fracture toughness obtained with a three point bending specimen loaded by Split Hopkinson Pressure Bars (SHPB). The three parameters are compared with the view of energy. The results show that the cavity expansion model is successfully used to set up a connection between spallation strength and dynamic uniaxial tensile strength of this material, while the energy release rate or the surface energy can give a good prediction of dynamic tensile strength and fracture toughness.
Investigation of Material Instability Behaviors Caused by Combined Stress Loadings
Authors: Ma Wei
Published: March 2013

This study involves the stability of plastic flow of thermoviscoplastic materials. The general instability criterion is proposed for determining the onset conditions of instability and the transition conditions among various plastic deformation behaviors. By using the phase diagram method, the transition of material instability modes under complex loading conditions is described and the analytical results are further validated with numerical examples.
Preliminary Study on Ductile Fracture of Imperfect Lattice Materials
Authors: Fang Dai Ning , Cui Xiao Dong
Published: March 2013

The ductile fracture behavior of two-dimensional imperfect lattice material under dynamic stretching is studied by finite element analyses (FEA). Three isotopic lattice materials, including the regular hexagonal honeycomb, the Kagome lattice and the regular triangular lattice, are taken into account, which are made of an elastic/visco-plastic metal material. Two typical imperfections (vacancy defect and rigid inclusion) are introduced separately. The numerical results reveal novel deformation modes and crack growth patterns in the ductile fracture of lattice material. Various crack growth patterns as defined according to their profiles, such as “X”-type, “Butterfly”-type, “Petal”-type. Crack propagation could induce severe material softening and plastic dissipation of the lattices. Subsequently, the effects of the strain rate, relative density, microstructure topology, and defect type on the crack growth pattern, the associated macroscopic material softening and the knock-down of total plastic dissipation are investigated.
Evaluation of Deformation Behavior of Silica-Filled Rubber under Monotonic and Cyclic Straining
Authors: Tomita Yoshihiro , Nakata Shinya , Naito Masato , Yashiro Kisaragi
Published: March 2013

To clarify the essential deformation characteristics of silica-filled rubber, we construct the finite element homogenization models of silica-filled rubber with newly proposed nonaffine molecular chain network model of rubber. These models can reflect the generation of complicated inter-fillers connecting phases where the characteristics of rubber are intricately changed depending on the volume fraction of silica coupling agent and relative size of particles and their location. The results obtained clarified the essential physical enhancement mechanisms of deformation resistance and hysteresis loss for rubber filled with silica with different distribution patterns under diffrent rate of deformation. The volume fraction of coupling agent essentially affects the deformation behavior of silica filled rubber which suggests the high controlability of the material characteristics of silica filled rubber as compared with carbon black filled rubber.
Surface Roughening and Formability in Sheet Metal Forming of Polycrystalline Metal
Authors: Abe Takeji
Published: March 2013

The r–value is defined as the ratio of the width strain to the thickness strain under the uniaxial tensile test of the sheet metal. Based on r-value of grains, a model of plastic deformation of polycrystalline metal and surface roughening after plastic deformation was proposed in the previous paper. Meanwhile, Marciniak and Kuczynski proposed the so-called M-K model which give the analytical estimation of the formability of sheet metal under biaxial stretching considering a certain irregularity of the thickness of the sheet metal. Yamaguchi et al showed that the experimentally measured surface roughness may correspond to the surface irregularity suggested in the M-K model. In the present paper, the formability of sheet metal under biaxial stretching is analyzed based on the previous analysis of surface roughening caused by the difference of the r-value in the sheet metal.
Development of Electromagnetic-Mechanical Coupled FE-Model for Thin Aluminum Plate Forming Using Electromagnetic Force
Authors: Shim Ji Yeon , Choi Young , Kang Bong Yong
Published: March 2013

The high cost of manufacturing and manufacturing time is required for preliminary experiment by manufacturing various type of coil every time for the forming of the required shape, it is essentially required to develop the coil design technology using a FEM. Thus, in order to form the required shape, it is important to design the coil using a FEM and predict the final forming product. Therefore, in this study developed electro-mechanical coupled FE-model for thin aluminum plate forming using electromagnetic force. In order to carry out this, magnetic pulse forming was carried by electromagnetic forming system total energy of 24kJ. Peck current and discharge speed acquired through magnetic pulse forming experiment using Rogowski current waveform transducer was used as input data in electromagnetic FE-model. Then, calculated electromagnetic force between forming coil and workpiece through the developed electromagnetic model was inputted as a load of mechanical FE-model for the prediction of thin aluminum plate forming shape. As results, developed electromagnetic-mechanical coupled model shall be able to be usefully used when designing the forming coil to secure the required forming shape later.
A Research on the Principle of Thermo-Stress Sizing and its Application for Titanium Alloy Sheet
Authors: Chen Ming He , Xie Lan Sheng , Liu Lei
Published: March 2013

The thermo-stress sizing is a technology that enables sheet metal part using high elastic material such as titanium alloy to eliminate spring-back and distortion. The paper expounds and proves the principle of fixing shape of thermal stress sizing, that is, they are synthetic effects of materia1 softening and stress relaxation in short time．Then the theoretical rule of hot sizing for bending spring-back is established by this principle．On the basis of principle of the thermo-stress sizing, relevant replication experiment is implemented. The results show quantitatively effects of main factors, such as material property, part geometry, temperature and time for the rule of hot sizing． The theoretical values of spring-back in the process of hot sizing are in good agreement with that of experiments. They may be used to estimate technological parameters of thermal stress sizing．In addition thermo-mechanical characteristics under standard temperatures of forming or sizing and the experimental curves of thermo-stress sizing for Ti-6Al-4V and Ti-2A1-1.5M n are given．
Influence of Intermediate Principal Stress Effect on Flat Punch Problems
Authors: Ma Zong Yuan , Liao Hong Jian , Dang Fa Ning
Published: March 2013

Using the finite difference code FLAC3D (Fast Lagrangian Analysis of Continua in 3 Dimensions) and UST (Uniﬁed Strength Theory), the influence of the intermediate principal stress effect on the problems of flat punch are analyzed in this paper. The values of the ultimate bearing capacity resulting from numerical analyses and the analytical solution of Prandtl’s strip punch problem are compared. The three-dimensional problems of strip, rectangular, square and circular punches on a semi infinite metallic medium have been analyzed.
Prediction of Springback of the One-Axle Rotary Shaping Based on Artificial Neural Network
Authors: Jin Xia , Lu Shi Hong
Published: March 2013

One-axle rotary shaping with the elastic medium (RSEM) is a kind of advanced sheet metal forming process. The research object is the springback of aluminous U-section. The orthogonal method is used to arrange the simulation experiments, the forming and springback of the workpiece are simulated successfully with the Finite Element Simulation software, and The main factors influenced the RSEM are analyzed. The simulation results are used as the training samples of the artificial neural network (ANN), and the ANN prediction model of RSEM process is set up. The prediction results would be tested with the experiment data, and only a little tolerance was existed between the two values. It demonstrated that the combination of orthogonal test, numerical simulation and neural network could effectively predict the springback of RSEM, the design efficiency of process parameters would be improved. It would guide the development of precision forming technology.