bluuebunny/crossref_metadata_2025 huggingface dataset:
CT Real-Time Analysis of Meso-Damage Propagation Law of Asphalt Concrete
Authors: Ai Chang Fa , Qiu Yan Jun , Xie Tao , Lan Bo
Published: March 2009

Cracking is one of the major distress types of asphalt pavements. Expected life of
pavements, pavement condition and maintenance cost are directly related to pavement cracking. It
is necessary to promote the understanding of cracking mechanism of hot mix asphalt (HMA) based
on fracture mechanics. Simulation, surveying, observation, and measurement of cracking in
pavement structures have been reported in literature in last three decades. However, cracking
process in asphalt mixtures in a three dimensional scale is still a great challenge to road engineers.
This paper reports a research effort of dynamic observation of the micro-fracture process of asphalt
mixture under compressed condition using CT (computerized tomography) method. Through CT
scanning, the clear CT images, which include the microcrack compressed, growth, bifurcation,
development, the crack fracture, and the asphalt concrete sample failure were obtained. The CT
numbers, CT images and the other data were analyzed. Analysis of the relationship between of CT
number and volumetric strain suggests that damage value at zero volumetric strain can be used as
threshold point in damage analysis. Corresponding stress value can be used as maximum allowable
stress in design practice.
Fatigue Damage Sensing in Smart Carbon Fiber Concrete by Electrical Resistivity Measurement
Authors: Xu Zhi Hong , Liu Zhi Tian
Published: March 2009

The possibility of sensing the damage in smart carbon fiber concrete (SCFC) during the
fatigue loading process by electrical resistance measurement is investigated in this paper. The
damages occurred and accumulated in the carbon fiber concrete specimens under the fatigue
loading destroy the local conductive network in the areas near the micro-cracks and cause the whole
volume electrical resisitivity increasing. It is verified that the resistance measurement has a great
potential to monitor and evaluate the damages in carbon fiber concrete during the whole fatigue
process on line.
The Interaction of a Cylindrical Elastic Inclusion with Semicircular Disconnected Curve and Linear Cracks in an Homogeneous Medium by SH-Waves
Authors: Hui Qi , Zhao Jia Xi
Published: March 2009

The scattering of SH waves by a cylindrical elastic inclusion with a semicircular
disconnected curve and linear cracks in an homogeneous medium is investigated and the solution of
dynamic stress intensity factor is given by Green’s function, complex function method. Firstly, we
can divide the space into up-and-down parts along the X axis. In the lower half space, a new suitable
Green’s function for the present problem is constructed.In the upper half space, the Green’s function
has been given by reference [5]. Thereby the semicircular disconnected curve can be constructed
when the two parts are bonded along the interface and the linear cracks can be constructed using the
method of crack-division and the integral equations can be obtained by the use of continuity
conditions at the X axis. Finally, some examples and results of dynamic stress intensify factor are
given and the influence of the parameters is discussed.
Experimental Study on Mechanical Behaviors of the Prestressed Concrete Girder
Authors: Chen Jing Xi , Zhang Guang , Li Hong Fei , Chen Fa Min
Published: March 2009

The prestressed concrete girder is a new type of bridge structure. Compared with the
traditional concrete girders, its crack resistance has been greatly improved. This type of new girders
was used in a certain viaduct in China. In order to probe working characteristics of this type of new
girders, some site tests, such as tension-camber test, concentrated load test, uniform load test and
mixed load test, were carried out. The results of the tests are analyzed and summed up in this paper.
Top Beam Flange Fracture Behavior in Steel Frame Connections under Gravity Loads
Authors: Liu Hong Bo , Zhai Chang Hai , Shao Yong Song , Xie Li Li
Published: March 2009

Top beam flange fractures were observed in the post-earthquake steel frame building
inspections. Both seismic loads and gravity loads have effect on top beam flange fractures. The
objective was to quantify the variation of stress intensity factor to weld root flaw sizes on top of the
beam flange at column face in steel frame connections under gravity loads. Finite-element analyses
were used to study fracture toughness in welded beam-column connections. Investigations of fracture
behavior mainly focused on the standard pre-Northridge connection geometry. Finite element
analysis was performed using the ANSYS computer program. Stress intensity factor was calculated
through a J-integral approach. The parametric study was conducted to quantify elastic fracture
demands as a function of beam geometries. Results show that the distributions of stress intensity
factor tend to be even across the flange width under gravity loads. The thickness of beam web has
little effect on stress intensity factors. Stress intensity factor increases nearly linear with the increase
of flaw size, and it increases with the increase of depth of beam and width of beam. Stress intensity
factor reduces with the increase of thickness of beam flange.
Analysis of Chloride Penetration into the Corner Zone of Concrete Structure Member
Authors: Wang Xiao Yong , Lee Han Seung , Jung Hai Moon
Published: March 2009

Chloride penetration into concrete is the main cause of steel corrosion in concrete
structures exposed to chloride-rich environments. In general, conditions on the diffusion process are
dominant among various penetration mechanisms, such as ionic diffusion, capillary sorption, and so
on. In recent analysis of current literature, chloride diffusion is as a simplified one-dimensional
diffusion process. However, for the rebar in the corner zone of concrete beam, the diffusion belongs
to a two-dimensional diffusion. Based on a galerkin finite element method, a two-dimensional
diffusion differential equation is built and solved numerically and the different chloride
concentration is compared to one dimensional diffusion and two-dimensional diffusion process. The
service life of concrete structure members under two-dimensional chloride penetration is predicted
by compared with a critical threshold chloride concentration. Compared with general
one-dimensional chloride attack, the service life is considerably reduced in a corner zone due to
two-dimension penetration.
The Influence of Longitudinal Stiffeners on Weld Toe Stress Concentrations in Multi Planar Tubular KK Joints
Authors: Woghiren Charles O. , Brennan F.P.
Published: March 2009

This paper reports a parametric stress analysis of various configurations of rack plate
stiffened multi-planar welded KK joints using the finite element method. The KK joint finds
application in the leg structure of offshore Oil & Gas jack-up platforms. The rack plate is a dual
purpose element of the joint because it firstly functions as a stiffener which reduces the stress
concentration at the brace/chord intersection. This could be an immense contribution to the increase
in fatigue life of the joint but other hot spot sites are introduced to the joint. The rack is also used
for raising and lowering of the jack-up hull which gives the jack-up platform its jacking capability.
Over 120 models using a combination of shell and solid elements were built and analysed within
ABAQUS. Non-dimensional joint geometric parameters; β, γ and . were employed in the study
with . being defined as the ratio of rack thickness to chord diameter. Stress Concentration Factors
(SCFs) were calculated under applied axial and OPB (out-of-plane-bending) loading. Three critical
SCF locations were identified for each load case, with each location becoming the most critical
based on the combination of the non-dimensional parameters selected for the joint. This is
important as careful design can shift the critical SCF from an area inaccessible to NDT to one that
can be easily inspected. The SCF values extracted from the models were used to derive six
parametric equations through multiple regression analysis performed using MINITAB. The
equations describe the SCF at the different locations as a function of the non-dimensional ratios.
The equations not only allow the rapid optimisation of multi-planar joints but also can be used to
quickly identify the location of maximum stress concentration and hence the likely position of
fatigue cracks. This in itself is an invaluable tool for planning NDT procedures and schedules.
An Experimental Study on the Development of Structural Lightweight Concrete Using Micro Foam Agents
Authors: Choi Jin Young , Lee Han Seung , Lee Byung Kwon
Published: March 2009

The purpose of this study is to obtain basic data on the properties of the development of
lightweight concrete containing a foam agent for various applications. This experiment confirmed
that compressive strength increased specific gravity, by changing the foam agent into a variable and
measuring the compressive strength of concrete.
Study on the Mechanism of Rebar Corrosion Considering the Relationship between Corrosion and Crack Width
Authors: You Jei Jun , Lee Han Seung , Ohno Yoshiteru
Published: March 2009

In this study, accelerated corrosion tests were conducted on concrete specimens with and
without accelerated carbonation beforehand for the purpose of elucidating the effects of carbonation,
cover depth, and water-cement ratio (W/C) on the reinforcement corrosion. During testing, the
corrosion current between the anode steel and cathode stainless steel was measured to continuously
monitor the progress of corrosion throughout the test period, thereby investigating the mechanism of
reinforcement corrosion and the relationship between corrosion and crack width, as well as other
parameters.
Temper Embrittlement and Fracture Control Method Based on NGS Theory and Grain Refinement Technique
Authors: Li Qing Fen , Cui Xin Fang , Zhou Hui Min , Liu Ming
Published: March 2009

Temper embrittlement and fracture control method based on both non-equilibrium
grain-boundary segregation (NGS) theory and grain refinement technique are studied in this paper.
Grain refinement technique by deformation induced phase transformation in low-alloy steels,
12Gr1MoV and 2.25Gr1MoNb, is investigated. A single-pass hot rolling process by using a
Gleeble-1500 system is performed. Experimental results show that steel strength and toughness may
be controlled and improved by grain refinement, and that the grain sizes were affected by the
deforming temperature, strain reduction, and strain rate. According to the NGS theory, a control
method of brittle fracture along grain-boundary is proposed so that some catastrophically brittle
fracture failure may be averted. Grain refinement may decrease both the concentration of
phosphorus at grain boundaries and the critical time. With the grain refinement technique, the
temper embrittlement of steel may be improved, and the critical time may be shortened. The cost of
heat treatment for fracture control will therefore be reduced.
Effect of Isothermal Holding Temperature on NGS Kinetics of Phosphorus and Temper Embrittlement
Authors: Wang Jun , Li Qing Fen , Liu Er Bao
Published: March 2009

When failure occurs in material, it is often occurs by fracture along some grain boundaries
and often by the micro-segregation of embrittling impurity to the grain boundaries. In the present
work, the non-equilibrium grain-boundary segregation (NGS) kinetics of phosphorus and the temper
embrittlement at the same solution treatment and different isothermal holding temperature in steel
2.25Cr1Mo are studied. The NGS kinetics curves of phosphorus at the same solution temperature
（1050 oC ）and different isothermal holding temperature (540 oC and 600 oC) are given. Experimental
results provide a direct evidence of NGS kinetic model and show that the grain boundary segregation
concentrations of phosphorus for specimen isothermal holding at 540 oC are higher than those at 600
oC. The peak values of AES patterns of solute atoms for specimen isothermal holding at 540 oC are
also higher than those at 600 oC. It is therefore concluded that the lower the isothermal holding
temperature, the higher the segregation concentration of phosphorus at the grain-boundaries, and also
the higher the degree of embrittlement.
Micromechanical Analysis of Composites with Short Fibers and Particles
Authors: Casaril Alexandre , Rovaris Gomes Eduardo , Soares Marcos Roberto , Al-Qureshi Hazim Ali
Published: March 2009

This work presents the investigation of the mechanical behavior of composite materials
strengthened with short fibers and particles. A simple model is presented, with the purpose of
predicting the fracture strength of this class of composite material. The model consists of the
modification of the rule of mixtures, by the introduction of a correction factor, which corresponds to
the adhesion of the resin to the fiber and the particles. The experiments were performed on three
different composite materials having the same raw material but different mixture ratios. The
composite materials produced were tested by the three-point flexural method, according to ASTM
standard, in order to determine their mechanical properties. The comparison between theoretical and
experimental results were also performed and found to be in reasonable agreement. Other relevant
parameters will also be discussed.
Automatic Mixed-Mode Crack Propagation based on a Combined Hexahedral-Tetrahedral Approach
Authors: Bremberg Daniel , Dhondt Guido
Published: March 2009

In the present paper, a new method for inserting cracks with out-of-plane features is presented.
Starting point is an arbitrary reference structure and a crack of any shape. The final cracked
structure is represented by hexahedral elements in the crack-front region and tetrahedral elements in
the remaining structure domain. The tetrahedron is employed to take advantage of the versatile
meshing capabilities and the collapsed quarter-point hexahedron gives good crack-tip behaviour.
Stress intensity factors are calculated from the asymptotic stress field, retrieved from the integration
points near the crack-tip.
Compression Test of Composite Sandwich Panel
Authors: Lee Jong Woong , Kong Cheol Won , Eun Se Won , Park Jae Sung , Jang Young Soon , Yi Yeong Moo , Cho Gwang Rae
Published: March 2009

Composite materials are used in aerospace structures due to their considerable bending
stiffness and strength-to-weight ratio. A composite sandwich is composed of a face-sheet and an
aluminum core. The face-sheet of the sandwich takes the bending stress and core of sandwich takes
the shear stress. A compression test and FEM analysis accomplished about composite sandwich
panels that have curvature. The FEM analysis was performed using a commercial code, ANSYS and
the compression test was performed until failure occurred in the sandwich panel. A strain gauge and a
displacement gauge were used to acquire the data. In this paper, the failure strength and failure mode
was checked. Additionally, the results of the test and analysis were compared.
Models for Optimization of Gantry Crane Main Girder
Authors: Aberšek Boris , Mikluš Samo
Published: March 2009

The optimization is the process of searching for the best results in a certain load case.
Complete definition of optimization includes three conditions, which are closely connected:
• optimization target, defined with object function,
• subject of optimization,
• optimization methods.
The object functions can be different process parameters such as costs, manufacturing time, costefficiency,
productivity etc. In designing of the structures such as a crane there is a tendency
particularly towards reducing the weight of steel structures with the same load-carrying capacity.
Thus the object function can be the volume, weight or mass of the structure.
In the paper we will devote ourselves to optimization of truss structures-gantry crane mean
girder by means of the FEM. This method has become indispensable in all areas of analyses of
structures in combination with mathematical modeling and mathematical methods of optimization
and is particularly of assistance to designers in conceiving the steel structures.
Fracture Analysis of Magnetoelectroelastic Composite Materials
Authors: Rojas-Díaz R. , García-Sánchez Felipe , Sáez Andrés , Zhang Chuan Zeng
Published: March 2009

This paper presents a crack analysis of linear magnetoelectroelastic materials subjected to
static loading conditions. To this end, an efficient boundary element method (BEM) is developed.
Unlike many previous investigations published in literature, two-dimensional (2-D) linear
magnetoelectroelastic materials possessing fully coupled piezoelectric, piezomagnetic and
magnetoelectric effects are considered in this paper. A combination of the displacement BEM and
the traction BEM is used in the present formulation. The displacement BEM is applied for the
external boundary of the cracked solid, while the traction BEM is used for the crack-faces. A
regularization technique is implemented to compute the strongly singular and hypersingular
boundary integrals in the BEM. The electric displacement intensity factor (EDIF), the magnetic
induction intensity factor (MIIF), the stress intensity factors (SIF), the mechanical strain energy
release rate (MSERR) and the total energy release rate (TERR) are evaluated directly from the
computed nodal values at discontinuous quarter point elements placed next to the crack tip. The
accuracy of the BEM is verified by analytical solutions known in literature. Results are presented for
a branched crack in a bending specimen subjected to combined magnetic-electric-mechanical
loading conditions.
Gurson Model and Conic Programming for Pressure-Sensitive Materials
Authors: Pastor Joseph , Thoré Philippe , Vandenbussche Cédric
Published: March 2009

In this talk we analyze the yield criterion of a porous material containing cylindrical and
spherical cavities on the basis of the Gurson mechanical model where the matrix is pressuresensitive.
Both limit analysis (LA) methods are used to determine as closely as possible the corresponding
macroscopic criterion, by using conic programming formulations. For a Drucker-Prager
matrix the case of cylindrical cavities is investigated in generalized plane strain, and the results
compared with those of previous works for von Mises matrices.
Then we study the case of a Coulomb matrix for spherical cavities under axisymmetrical conditions.
Due to the constraining character of the axisymmetry, specific analytical solutions are superimposed
on the numerical fields. Among other results, a comparison with an ad hoc translated
“modified Cam-Clay criterion” points out that it might be considered as a satisfactory approximation,
except that it does not account for the corner of our criterion on the isotropic compressive axis,
unlike the original Cam-Clay criterion.
Modelling Crack Growth in the Life Assessment of Elevated Temperature Components
Authors: Nikbin Kamran M.
Published: March 2009

Modelling of Creep Crack Growth (CCG) using analytical and numerical methods is
relevant to life assessment procedures of components operating at elevated temperatures. This paper
compares an analytical crack prediction and a numerical based virtual CCG technique used in
fracture mechanics components with sample experimental results. Two approaches are presented.
First the well developed strain exhaustion model called the NSW and the modified NSW-MOD
models which predict plane stress/strain bound crack initiation and growth rates for engineering
alloys and the second a damage-based approach used to numerically predict the crack propagation
rate in Finite Element models of fracture mechanics specimens. The results from both methods are
correlated against an independently determined C* parameter. As an example the NSW and the
extended NSW-MOD strain exhaustion models are applied to compare to the experimental data and
FE predictions for two steels at Carbon-Manganese steel tested at 360 oC and a weld 316H stainless
steel at 550 oC. For values of C* within the limits of the present creep crack growth data presented
the plane strain crack growth rate predicted from the numerical analysis is found to be less
conservative than the plane strain NSW model but more conservative than plane strain NSW-MOD
model.
An Experimental Study on the Influence of Steel Bar Corrosion in the Structural Performance of Bridge Piers
Authors: Kang In Seok , Lee Han Seung , Jung Hai Moon , Ahn Tae Song
Published: March 2009

Economic losses due to the corrosion of steel structures in concrete is almost about 4% of
GNP. It is almost 70 billion dollars in America. Also, The Korean economy is expected to experience
a 4～5% loss in GNP in the near future in by considering the industrial background that has been
formed by heavy industries. Although deteriorations in concrete structures demonstrate a high
diversity of factors, it finally comes down to the lowering of water resistance performance in
structures based on the crack generation due to the corrosive expansion of steel bars. Thus, it is very
important to investigate the lowering of water resistance performance in structures according to the
level of the corrosion in steel bars.
Effect of Roughness on Fatigue Life of Open Holes
Authors: Liu Yong Shou , Liu Jun , Shao Xiao Jun , Yue Zhu Feng
Published: March 2009

The fatigue testing of the specimen with a central open hole was carried out to investigate
the influence of the surface roughness on the fatigue lifetime. Fracture morphology investigations
were used by scanning electron microscope. The reliability analysis of the specimen was carried out
by detail fatigue rating. The results revealed that the less the roughness is, the longer the fatigue life
of open hole and the higher the value of DFR (Detail Fatigue Rating) is. Under the same
technological conditions, the effect of corner crack on fatigue life of open holes is greater than the
effect of internal crack. So, the effect of a decrease of roughness on the fatigue life of an open hole is
similar to a change of crack type from a corner crack to an internal crack.
Fully Coupled Fatigue Damage Analysis of Welded Steel Bridge Member under Traffic Loading
Authors: Zhou Tai Quan , Hua Yuan , Chan Tommy Hung Tin
Published: March 2009

The finite element analysis fully coupled fatigue damage evolution is implemented on
the user subroutine UMAT of the finite element software ABAQUS. The fully coupled method
developed with damage mechanics and the finite element analysis is performed on calculation of
fatigue damage accumulation of the critical welded member in the Tsing Ma Bridge. The calculated
result shows that the fatigue damage in the critical welded member is accumulated in the region of
toe of welding. The value of faitgue life calculated by the fully coupled method is smaller than that
by the uncoupled method, which suggests that there exists interaction between the fatigue damage
evolution and the structural response. The linear Miner’s Law is widely used however conservative
for the evaluation of fatigue life of bridge on service. The above results provide feasible method for
accurate evaluation of fatigue damage in bridge components based on the hot spot stress analysis
and the damage mechanics theory.
A Probabilistic Extended Finite Element Approach: Application to the Prediction of Bone Crack Propagation
Authors: Grasa Jorge , Bea José Antonio , Doblaré Manuel
Published: March 2009

The Extended Finite Element Method (XFEM), has become a well-known tool to
simulate crack propagation problems using non-structured meshes avoiding the remeshing process
usually needed in this type of problems and allowing the inclusion of appropriate shape functions
that reflect the asymptotic displacement field, near the crack tip, via a partition of unity fracture
approach. However, in this kind of numerical applications, all the variables involved have been
considered as deterministic (defined by a single given value), despite the well-known uncertainty
associated to many of them (external loads, geometry and material properties, among others). The
combination of the XFEM and probabilistic techniques is here proposed and formulated allowing
treating fracture mechanics problems from a probabilistic point of view. We present the
implementation of this probabilistic extended finite element method and apply it to the prediction of
the appearance and propagation of a femur’s neck fracture under probabilistic loads.
An Experimental Study on the Influence of Steel Rod Corrosion in Concrete Cracks
Authors: Jung Hai Moon , Lee Han Seung
Published: March 2009

The purpose of this study is to define the amount of critical corrosion in steel that causes
cracks on the cover of concrete. Major variables in the amount of critical corrosion are concrete
strength, thickness, and the cover of concrete. In this experiment, stress concentration is a newly
added factor. According to the results of this experiment, it is evident that the amount of critical
corrosion decreased according to the increase in stress concentration factors. In addition, electric
currents were measured using a constant voltage generator. When a constant voltage was connected
to the corrosion circuits, it was discovered that the magnitude in the change was similar to the
displacement on the cover of concrete and the electric current according to time.1)
An Experimental Study on the Performance Evaluation of RC Beams to Calculate the Partial Reduction Coefficient of High Strength Glass Fiber Transparent Composite Panels
Authors: Kang In Seok , Lee Han Seung , Kim Jae Deog , Jang Jae Ho , Seong Jing Yeong
Published: March 2009

As concrete is a type of porous materials, water or air freely permeates concrete. Therefore
the durability of concrete decreases. However, porous material with a rust inhibitor may allow
permeation of water into concrete. In addition, there may be permeation of water through the rust
inhibitor at the location of steel frames. The objective of the study is to investigate the penetration
depth of concrete under water forced conditions with pressure.
Stiffness Reduction for Flat Plate Systems due to Cracking
Authors: Park Young Mi , Han Sang Whan , Cho Ja Ock
Published: March 2009

The purpose of this study is to propose a stiffness reduction factor for flat plate systems
under lateral loads. According to current design provisions, slab stiffness under lateral loads should
account for stiffness reduction due to the effects of cracks. Several researchers have conducted for
evaluating the stiffness reduction in flat plate slab systems under lateral loads. However, no
research is found for establishing strength reduction factor with respect to the level of applied
moment. This study attempted to propose equations for calculating stiffness reduction factor with
respect to the level of applied moment (Ma) represented by the ratio of Ma to the cracking moment
of the slab (Mcr). For this purpose, test results of 20 interior slab-column connections were
collected. For each specimen, stiffness reduction was measured with respect to Ma/Mcr. To verify
the proposed factor, this study conducted the experimental test of interior connection under quasistatic
cyclic loading, from which load-deformation curve was obtained. The curve was compared
with that obtained from the effective beam width method with the proposed stiffness reduction
factor. It shows that the proposed factor accurately predicts stiffness reduction in flat plate systems.
Experimental Study on K-Dominance of Static Crack Tip in Functionally Gradient Materials
Authors: Xu Wei , Yao Xue Feng , Wu Lin Zhi
Published: March 2009

In this paper, coherent gradient sensing (CGS) and digital speckle correlation method
(DSCM) are introduced to study the K-dominance of static crack tip in functionally gradient
materials (FGMs) with a crack oriented along the direction of the elastic gradient. And the
numerical simulation is analyzed through finite element method (FEM). Firstly, the CGS and
DSCM equations at the mode-I static crack tip of FGMs are developed, which can be used to
calculate the stress intensity factors of FGMs. Secondly, three kinds of FGMs specimens with
different variation of the modulus are prepared to observe the influences of the property variation
on the K-dominance. Then three-point-bending experiments are carried out. The interference fringe
pictures of CGS and the speckle patterns for DSCM on the specimens are shot through the camera.
Thirdly, based on the results of the experiments, the stress intensity factors of three kinds of FGMs
specimens are calculated by CGS and DSCM. Meanwhile, the stress intensity factors are obtained
by FEM. Finally, comparing the results from CGS, DSCM and FEM, the K-dominance of mode-I
static crack tip in FGMs is discussed in detail. It is found that the K-dominance of FGMs and
homogenous material is almost same when the gradient index in FGMs is relatively small.
Fracture Analysis on the Invasion Problem of the Porous Material
Authors: Tang Li Qiang , Yang Yong , Yang Jing Yuan
Published: March 2009

The power law hardening constitutive relations for porous material were established by the
material yield function. An idealized interface fracture model was established in which the indenter as
rigidity was embedded in the porous material. Under the condition of plane strain, through the
analysis of the singularity of the stress and strain and combining the motion and compatibility
equations, the governing equation of the wedge-tip was deduced. With the help of numerical
calculations and boundary conditions, the asymptotic solutions of the stress and strain near the
wedge-tip were obtained. Finally, the influence of the material constants α (pressure sensitive
coefficient), the angle of the indenter and the interfacial friction on the fracture of the porous material
was discussed.
Mechanical Behavior of High-Tension Bolted Joints with Varying Bolt Size and Plate Thickness
Authors: Lee Seung Yong , Park Cheol Woo , Kwon Soon Cheol , Lee Hee Hyun
Published: March 2009

The use of steel plates has been greatly increased in bridge construction, particularly for
long-span bridges, and connections between the plates are made usually using high-tension bolts.
However, the specifications on the use of large-sized high-tension bolts are not adequately stated in
the currently available construction manuals. In order to provide further information on the use of
the large-sized high-tension bolts, this study experimentally investigated the relaxation and slip
behavior of M30 bolts with varying bolt size and plate thickness. In addition, numerical evaluation
using FEM was performed to investigate the compressive stress occurred on the inside of bolt hole.
The analyzed results were compared with the stress distribution measured from strain gages
attached on the bolts and bolt holes. From the study presented herein, it was found that the
relaxation was increased as the size of bolt increased, and that the M30 high-tension bolts
developed slip coefficient greater than 0.4. The thickness of plate did not significantly affect the
compressive stress distribution around the bolt holes.
Slow Strain Rate Tensile Testing for Evaluating Stress Corrosion Cracking of Type-40Cr Steel in the Acidic Chloride Solution
Authors: An Li Juan , Zhao Yong Tao , Li Qing Fen
Published: March 2009

This paper investigates application of slow strain rate tensile (SSRT) testing as a
laboratory method to characterize stress corrosion cracking (SCC) susceptibility of type 40Cr steel
in the acidic chloride solution. SSRT testing was carried out at room temperature in acidic chloride
solution and seawater at different strain rates (3.82×10-7 to 1.41×10-6 s-1)，respectively. The results
show that the type 40Cr steel is susceptible to stress corrosion cracking in a certain strain rates
(around 1.41×10-6 s-1) in the acidic chloride solution. In tests performed at this strain rate (1.41×10-6
s-1), while the specimens are not susceptible to SCC in seawater. Typical intergranular attack is seen
on the fracture surface of the former that had failed due to SCC, and the latter had underwent
considerable necking before fracture, also represented by high reduction of area (RoA) and
fractographic feature of dimples consistent with ductile failure. Additionally, the results are
consistent with the data of electrochemical noise (EN) that is generated of type 40Cr steel exposed
to the acidic chloride solution and seawater. This study also supports SSRT and EN technique as an
effective testing technique for SCC studies.
A Study on Normal Stress Distribution and Failure of Adhesively Bonded Joint under Cleavage Loading
Authors: Zheng Xiao Ling , Zhang Ming Song , You Min , Yu Hai Zhou , Li Zhi
Published: March 2009

The normal stress distributed in the mid-bondline of the adhesively bonded joint under
cleavage loading was investigated using the elastic finite element method (FEM) and the strain
gauges method to reveal the real normal stresses distribution in the metal-to-metal joint while the
load was increased. The results from the finite element analysis (FEA) showed that there is always a
peak stress of the normal stress Sy in the mid-bondline occurred at a point close to the loading pin
axis. When the load was increased from 0.5 kN to 3 kN, there was also a point located at about x =
16mm along the length of specimen where there is without any normal stress at all. The result of
stress Sy from the FEA is nearly the same as that one obtained from the strain gauges method. It was
also found that there was a evidently hardness change in the bonded zone of the adherend made from
structural steel or pure copper, which can be used to explain the procedure of the joint and discuss
the distribution model of the normal stress Sy in the joint under the cleavage loading.
Morphology Control of Zirconia Thin Films Prepared Using Photochromic Precursors
Authors: Nishizawa Kaori , Fukaya Haruhiko , Miki Takeshi , Suzuki Kazuyuki , Kato Kazumi
Published: March 2009

A new photochromic ZrO2 precursor solution was prepared using zirconium tetra-n-butoxide,
4-(phenylazo)benzoic acid and ethyleneglycol monomethylether. The density functional theory
(DFT) calculation has identified that the structure of the synthesized precursor molecule changed by
UV irradiation. The two kinds of thin films were prepared using the photosensitive ZrO2 precursor
solution without and with UV irradiation. The surface morphology of thin films changed by UV
irradiation. It was found that the surface morphology of thin films is controlled by the difference of
precursor structure introduced by UV irradiation.
Behavior of γ-MnO2 Containing TiB2 as a Cathode in Aqueous Lithium Hydroxide Electrolyte Battery
Authors: Minakshi Manickam , Singh Pritam , Carter Melody
Published: March 2009

The redox behavior and surface characterization of manganese dioxide (MnO2) containing titanium boride (TiB2) as a cathode and Zn as an anode have been investigated in aqueous saturated lithium hydroxide (LiOH) electrolyte battery. The electrode reaction of MnO2 with TiB2 in this aqueous electrolyte is shown to be lithium insertion rather than the usual protonation. The influence of TiB2 additive (1, 3 and 5 wt. %) on the performance of MnO2 as a cathode and its cycling ability have been determined.
Effects of the Substitution of Β-Site Ion on Oxygen Reduction Electrode Properties of Pb2Ru2O7- δ in Aqueous Solutions
Authors: Yoshihara Kenji , Saito Yoshinobu , Saito Morihiro , Kuwano Jun , Shiroishi Hidenobu
Published: March 2009

The activities of the pyrochlores Pb2Ru2-xMxO7-δ (M=Mn,Fe,Co,Ni)[PRM(0x)] toward
electrochemical oxygen reduction (EOR) were examined in 0.1 M KOH and 0.05 M H2SO4 aqueous
solutions. The onset voltage (Vo) and the efficiency (E4) of 4-electron reduction of oxygen for
PRM(0x) were evaluated by semi-steady state voltammetry with rotating ring-disk electrodes. In
PRM01, the order of the EOR activities was PRMn01 > PRCo01 > PRNi01 > PRFe01 in both
solutions. This was consistent with the variation of the lattice parameters, i.e. PRM01 with a smaller
lattice parameter showed higher EOR activity. In addition, PRMn05 showed higher EOR activity
than PRMn01. The onset voltages Vo were 0.95 and 0.50 V vs. reversible hydrogen electrode in 0.1
M KOH and 0.05 M H2SO4, respectively, while E4 was almost 100 % in both solutions. These
results indicate that the EOR activity of PRM(0x) depends on the incorporated metal ions on the
B-sites and their contents.
Liquid-Phase Synthesis of Carbon Nanotubes from Alcohols
Authors: Yamagiwa Kiyofumi , Iwao Yuriko , Mikami Masafumi , Takeuchi Tsuneharu , Saito Morihiro , Kuwano Jun
Published: March 2009

Vertically aligned carbon nanotubes (CNTs) were grown on a stainless steel substrate (SUS304) by resistance-heating method in alcohols containing homogeneously dissolved cobaltocene Co(C5H5)2 as a catalyst source. Straight-chain primary alcohols, 1,2-ethanediol and cyclohexanol were used as carbon sources to examine the effects of the molecular structures on the morphology of the aligned CNTs. Methanol brought the best purity and alignment of CNTs of all the alcohols. The CNTs from 1,2-ethanediol was worse in the purity than those from ethanol with the same number of carbon atoms. The CNTs from cyclohexanol had a better purity than those from 1-hexanol. Distinctive features of this method are simple, low cost and a one-step process involving none of vacuum processes and catalyst preparation processes.
Hot Workability of the Mg65Cu20Y10Ag5 Amorphous/ NanoZrO2 Composite Alloy within Supercooled Temperature Region
Authors: Chang L.J. , Fang G.R. , Jang Jason S.C. , Lee I.S. , Huang J.C. , Tsao Chi Y.A.
Published: March 2009

Mg65Cu20Y10Ag5 Amorphous/ nano ZrO2 composites alloy powder were fabricated through the combination method of melt spinning and mechanical alloying (MA). The melt spun amorphous matrix ribbons are ground into powders and mixed with 3 vol.% ZrO2 nano particles in the planetary mill. After then formed by hot pressing in Ar atmosphere under the pressure of 700 MPa at the temperature of soft point which measured by TMA (Thermal mechanical Analysis). The hot-pressed bulk composite specimens are compression tested at different temperature within the supercooled temperature region. The flow stress was found decrease with increasing temperature dramatically when the temperature exceeds the middle temperature of supercooled region. The specimens after compression test were examined by X-ray diffractometry and SEM to investigate its crystallinity and fracture mechanism.
Effects of Particle Size on the Thermal Physical Properties of SiCp/Al Composites
Authors: Geng Lin , Yan Yi Wu
Published: March 2009

The coefficients of thermal expansion (CTEs) of the 20 vol% SiCp/Al composites
fabricated by powder metallurgy process were measured and examined from room temperature to
450°C The SiC particles are in three nominal sizes 5μm, 20μm and 56μm. The CTEs of the SiCp/Al
composites were shown to be apparently dependent on the particle size. That the larger particle size,
the higher CTEs of the composites, is thought to be due to the difference in original thermal residual
stresses and matrix plasticity during thermal loading. The thermal conductivity of the composites
also increases with particle size increasing.
Deformation and Fracture Behavior of 7039 Al Reinforced with B4C Particles at Elevated Temperature
Authors: Nie Cun Zhu , Gu Jia Jun , Liu Jun Liang , Zhang Di
Published: March 2009

The elevated temperature deformation and fracture behavior of an 10vol%B4CP/7039 aluminum matrix composite plate was investigated by uniaxial tensile tests at temperatures ranging from573 to 773 K and at initial strain rates from 1x10-1 to 1x10-4s-1.The strain rate sensitivity exponent was found to be approximately 0.1-0.15 which was below that of a superplastic material. A maximum elongation of 116% was obtained at an initial strain rate of 10-1 s-1 and at a temperature of 773 K.
Fretting Wear of SiC and Ni3Al Particles Reinforced Al Alloy Matrix Composites
Authors: Chen Rong , Wang Hong Hua , Zhang Di , Zhang Guo Ding
Published: March 2009

Fretting friction and wear of aluminum alloy, 5 and 10 vol.% SiCp/Al and Ni3Alp/Al composites under 5×10-4 Pa and atmosphere was investigated. Wear mechanism in vacuum was compared to that in atmosphere at different applied loads. The coefficient of friction (COF) of the SiCp/Al composites was larger than aluminum and Ni3Alp/Al composites, however, incorporation of SiC particles into Al alloy increased the fretting wear resistance of Al alloys, especially in vacuum. It should be notices that the maximum wear depth was larger in vacuum under fretting wear, and the Ni3Alp/Al composites show low fretting wear resistance.
Preparation and Characterization of Ta3N5 Nanoparticles
Authors: Zhang Qing Hong , Gao Lian
Published: March 2009

In this paper, we reported the preparation of nanocrystalline Ta3N5 particles by
nitridation of Ta2O5 nanoparticles using NH3 as reactant gas. It was found that nanocrystalline
Ta2O5 was converted into Ta3N5 completely at 700°C within 5.0 h, which was much lower than the
temperature 850°C for the complete nitridation of micron-sized Ta2O5 powder. The resulting nitride
was characterized by X-ray diffraction analysis (XRD) and field emission scanning electron
microscopy (FE-SEM). The nitrogen contents in the prepared Ta3N5 powders were quantitatively
determined with CHN elemental analyzer and thermogravimetry and differential scanning
calorimetry (TG-DSC). The color of nanocrystalline Ta3N5 is in fresh red while the one of
micrometer-sized Ta3N5 is in dark red.
Densification and Thermal Conductivity of Y2O3-Doped AlN Ceramics by Spark Plasma Sintering
Authors: Shen Qiang , Wei Z.D. , Li Mei Juan , Zhang Lian Meng
Published: March 2009

AlN ceramics doped with yttrium oxide (Y2O3) as the sintering additive were prepared via the spark plasma sintering (SPS) technique. The sintering behaviors and densification mechanism were mainly investigated. The results showed that Y2O3 addition could promote the AlN densification. Y2O3-doped AlN samples could be densified at low temperatures of 1600-1700oC in 20-25 minutes. The AlN samples were characterized with homogeneous microstructure. The Y-Al-O compounds were created on the grain boundaries due to the reactions between Y2O3 and Al2O3 on AlN particle surface. With increasing the sintering temperature, AlN grains grew up, and the location of grain boundaries as well as the phase compositions changed. The Y/Al ratio in the aluminates increased, from Y3Al5O12 to YAlO3 and to Y4Al2O9. High-density, the growth of AlN grains and the homogenous dispersion of boundary phase were helpful to improve the thermal conductivity of AlN ceramics. The thermal conductivity of 122Wm-1K-1 for the 4.0 mass%Y2O3-doped AlN sample was reached.
Preparation and Electrical-Conductive Property of SnO2-Based Ceramics with 0.5% CuO and Sb2O3
Authors: Zhang Lian Meng , Luo Guo Qiang , Li J. , Zhang Dong Ming , Shen Qiang
Published: March 2009

In this study, SnO2-based ceramics, with 0.5%CuO as sintering aid and Sb2O3 as activator of the electrical conductivity, was obtained by pressureless sintering at 1450°C for 5 h. Densification behavior and microstructure development strongly depend on Sb2O3. The characteristization of microstructures on Sb2O3 concentrations are analyzed by SEM. A small amount of CuO improves densification; Sb2O3 retards the densification of SnO2-based ceramic. The electrical resistivities of SnO2-based ceramics with different contents of Sb2O3 are measured by the standard four probe method and varied in a wide range. The electrical resistivity arrives the minimal value of 4.964×10-2 0·cm for 99%SnO2+0.5%CuO +0.5%Sb2O3. More content of Sb2O3 than that of CuO causes the degression of density and the increasing of electrical resistivity of ceramics.
DNA Damage Upon UV Illumination in the Presence of Inorganic UV-Shielding Materials
Authors: Sato Tsugio , El-Toni Ahmed Mohamed , Yin Shu , Hidaka Hisao
Published: March 2009

White nanoparticles of calcia-doped ceria were prepared from the precipitate by reacting
CeCl3-CaCl2 mixed solution with NaOH solution at pH 12 and the oxidation with hydrogen peroxide
solution at 40oC, followed by the calcination at 700oC for 1 h. Ceria particles generated far less singlet
oxygen and caused far less damage to the DNA plasmids upon UV illumination than either the titania
or the zinc oxide reference pigments.
Morphology of Epitaxially Grown BaRuO3 and CaRuO3 Thin Films by Laser Ablation
Authors: Ito Akihiko , Masumoto Hiroshi , Goto Takashi
Published: March 2009

Epitaxial BaRuO3 (BRO) and CaRuO3 (CRO) thin films were prepared on (001), (110) and
(111) SrTiO3 (STO) single-crystal substrates by laser ablation, and their microstructures and
anisotropy of electrical conductivity were investigated. The (205) (104), (110) and (009) oriented
BRO thin films, and (001), (110) and (110) oriented CRO thin films were grown epitaxially on (001),
(110) and (111) STO substrates with in-plain orientation, respectively. The (009) BRO thin film and
(001) CRO thin film has a flat surface result from a good lattice matching to STO substrates. The
(205) (104) BRO thin film and (111) CRO thin film exhibited orthogonal- and hexagonal-shaped
texture, respectively. The (110) BRO thin film and (110) CRO thin film showed an island growth due
to (110) surface feature of cubic perovskite structure. Epitaxial BRO and CRO thin films have a high
electrical conductivity with a metallic conduction, the (111) CRO thin films exhibited the highest
conductivity of 1.4×105 S·m-1.
Characterization of Mechanical Properties of Brittle Coating Systems by Various Indentation Techniques
Authors: Kim Jong Ho , Kim Young Gu , Lee Hyeon Keun , Kim Do Kyung
Published: March 2009

The mechanical properties of brittle coating structures were characterized by various
indentation techniques. The adhesion properties of the coatings were evaluated by in situ scratch and
sphere indentation method. Physical vapor deposited TiN coatings on transparent substrates,
sapphire, were scratched by diamond cone indenter and in situ observed through the transparent
substrate. In situ scratch results reveal that the failure of coating is originated from the damage of the
substrate and the plastic deformation of substrate is a primary factor for determining the adhesion
breakage. The unique characterization technique for the strength measurement of brittle thin coating
has been developed. The strength of the thin coating was evaluated by the sphere indentation on the
trilayer structure. The CVD SiC coatings on graphite were characterized by the technique. It is
concluded that the microstructure of SiC coatings influences the strength. In this paper, the various
indentation technique were applied to evaluate the mechanical properties of TiN and SiC coatings and
the effect of microstructure on the reliability of the brittle coating system was discussed.