bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Packing Density of Micropowders on the Compressive Strength of Cement Pastes
Authors: Gong Jian Qing , Xiao Han Ning , Huang Zheng Yu , Li Jiu Su , Cao Rong Kui , Mao Dan
Published: March 2009

This study was performed to evaluate the effects of micropowders content on the
compressive strength of cement-based composite pastes. Granular ground blast slag (GGBS), grade
I fly ash (FAI), ultra fine fly ash (UFA) and silica fume (SF) were selected as the micropowders.
The compressive strength was tested after 3d, 7d and 28d curing. Results show that the paste
containing both UFA and SF has the highest packing density and corresponding excellent
compressive strength. The higher the packing density is, the better the compacting and filling effect
of micropowders will be, which contributes to developing higher compressive strength of
cement-based pastes.
Stress-Strain Response in SiC/SiC Composites under Cyclic Loading
Authors: Ohgi Jun Ji , Tanaka S. , Kuramoto T. , Suzuki M. , Goda Koichi
Published: March 2009

The tension-tension fatigue tests for SiC/SiC composites were performed under the
conditions that the maximum load Pmax was 80-90% to the fracture load of the tensile tests and the
stress ratio was Rσ = 0.5. The composites exhibited a width in stress-strain hysteresis loop under
one load cycling. In some cases the mean strain εmean gradually increase with increasing in number
of cycles. These variations would reflect the developments of the fatigue damage at the fiber/matrix
interface during the cyclic loading process. The pull-out lengths of the fibers for the fatigued- and
not fatigued-specimens were measured through the SEM observations after the tensile test. In all
materials, the average pull-out length of fibers in fatigued material was larger than in not fatigued
material because the cyclic loading affected on the fiber/matrix interfacial strength.
Mechanical Force Induced Grafting Effect on Strengthening HDPE/GF Composites with Maleic Anhydride
Authors: Zhou Xian Feng , Dai Guang Ze , Dong Li Xin , Liu L.L. , Ni Qing Qing
Published: March 2009

Grafting of maleic anhydride (MAH) onto high density polyethylene (HDPE) was carried
out in melt state through the mechanical force initiation caused by high-speed rotation of the
twin-screw, investigating its functional reaction and the grafting degree influenced by the rotation of
the twin-screw, observing the influence on its mechanical property. The results showed that the
increase of grafting degree made the interface phase produce a firm chemical coupling, which
improved the tensile-strength and flexural strength of the composites. The produced interfacial
stress from the shrinkage of specimen melts in injection molding process can strain-induce the
forming of the extended-chain crystals in the matrix and obviously improve the notched impact
strength of the composites.
In Situ Combustion Synthesis of h-BN-SiC High-Temperature Ceramics
Authors: Li Hong Bo , Zheng Yong Ting , Han Jie Cai
Published: March 2009

The feasibility of fabricating h-BN-SiC high-temperature ceramics by in-situ combustion
synthesis was demonstrated by igniting the mixture of boron carbide and silicon powder under
100MPa nitrogen pressure. The reaction thermodynamics and the adiabatic combustion temperature
were calculated theoretically. The phase composition, microstructure and mechanical properties of
composite were identified by XRD and SEM. The maximum bending strength and fracture
toughness of the composite were 65.2 MPa and 1.4 MPa·m1/2 under room temperature, respectively.
The effects of h-BN and SiC dilution contents on the mechanical properties of composite were also
discussed.
Microstructures of ZrO2 (3Y) Ceramics after Dynamic Impact
Authors: Duan Xiao Ming , Zhou Yu , Jia De Chang , Wang Dong Liang
Published: March 2009

ZrO2(3Y) ceramics were sintered by vacuum hot-pressing and impacted by split Hopkinson
method. The microstructure of the materials was studied by X-ray diffraction and scanning electron
microscopy. The results show that the phase transformation from tetragonal phase to monocline phase
occurred in the ceramics during dynamic loading process, and the transformation rate is about 30%.
From the results of scanning electron microscopy, it can be found that the microcracks formed in the
materials under the dynamic loading, and there is a kind of liked-amorphous layer appeared on the
fragment surface.
Fatigue Crack Propagation Behavior Near Fusion Line between SA508 Steel and Ni-Based Buttering Metal
Authors: Lee Ho Jin , Kim Maan Won , Lee Bong Sang
Published: March 2009

Fatigue crack propagation behavior near the fusion line between SA508 ferritic steel and
Ni-based buttering metal was studied to assess the integrity of dissimilar metal welded zone in reactor
pressure vessels. Ni-based filler metal has been used as a buttering or filler metal to weld the ferritic
steel to the Ni-alloy or austenitic stainless steel. The J integral value and stress field at the crack tip in
a simulated small-CT welded specimen model was calculated by using the commercial FE calculation
code to anticipate the effect of the yield strength differences between dissimilar metals. If the
Ni-based buttering metal has lower yield strength, which means the decrease of material constraint by
the weld metal, the J integral value of the crack tip in the base metal near the fusion line was
calculated higher than that of the base metal. The fatigue crack propagation behavior near the fusion
line was measured by using the small-CT welded specimens of 5 mm thickness. The relationships
between da/dN and )K were measured in the base metal and the HAZ near fusion line. The yield
strength of the weld metal including microstructure at the joint can be considered more effective than
the material constraint on explaining the behavior of fatigue crack propagation near the fusion line.
Influence of 3Y-TZP on Microstructure and Mechanical Properties of Al2O3-Based Composites
Authors: Weng Ming Tsung , Wei Wen Cheng J. , Huang Chi Yuen
Published: March 2009

Al2O3 composites with different volume fractions of 3Y-TZP (3 mol% yttria-doped
tetragonal zirconia polycrystalline) were prepared by using a colloidal process and pressure-casting
into green specimens, then were pressureless sintered to full density at 1550oC. The resulted
two-phase microstructure contained uniformly distributed and submicro- meter-sized grains. The
addition of 15 vol% ZrO2 resulted in an increase in bending strength (average 656 MPa by 4 pt.
test). Appreciate amount of m-ZrO2 phase was detected after fracture. The enhanced
transformability results in an increase in flexural strength and toughness. The addition of 30 vol%
ZrO2 resulted in best toughness (5.4 MPam0.5) and outstanding wear resistance (7.2×10-8 cm3/Nm).
Effects of Particle Distribution on the Residual Thermal Stresses of (W,Ti)C/SiC/Al2O3 Ceramic Composite
Authors: Xu Chong Hai
Published: March 2009

Effects of the body centered cubic distribution of the dispersed SiC and (W,Ti)C particles
on the residual thermal stresses of (W,Ti)C/SiC/Al2O3 ceramic composite were analyzed with the
finite element method, especially with the comparison with that of the face centered cubic
distribution. Results show that the residual thermal stress is affected not only by each material
compositions but also by the distribution forms of the dispersed SiC and (W,Ti)C particulates. Both
distribution and magnitude of residual thermal stress differs with the difference in the particle
distribution forms. The calculation results of different particle distribution forms, however, are just
the reflection of different cases of the residual thermal stresses inside the ceramic composite from
different points of view. Both reflections can research agreement in trends.
Growth Pattern Study of Closed Surface Flaw under Compression
Authors: Guo Y.S.H. , Zhu Wei Shen , Li Shu Cai , Wong R.H.C. , Sin B.
Published: March 2009

Under extra compressive stress, some phenomena of rock spallings and fractures often
exist on rock mass located in sidewalls of underground house and tunnels. It is the reason that the
crack growth and coalescence initiation from original flaws (or faults) in rock mass. In the previous
studies, many researchers took a flaw as a through flaw (2-dimentional model), but the flaws are not
always through the whole rock mass in fact, most of them are only near the surface of rock mass,
These are so named as surface flaws. They belong to three dimensional (2-D) flaws. Now, the
reports on initiation and growth of 3-D surface flaw are few. So, for the investigation on growth
patterns of 3-D surface flaw, a series of samples containing a surface flaw were carried out using
frozen casting resin material at about -30°C temperatures. The surface flaw was made of a polyester
film was used to model a single closed flaw on rock mass. The experimental results show that the
wrapping wing crack (Mode I) initiated at the ends (or tips) of surface flaw first, and then formed a
kinking zone (mixed crack zone) at a certain place at the middle of surface flaw region. Some petal
cracks (Mode III) and shell-shaped cracks (Mode III) would grow at the middle place of flaw. A big
fin crack (Mixed Mode) also emerged in middle of flaw and grown along loading direction. Finally,
a team of large cracking curved faces deformed inside the resin specimen; the whole specimen
would be splitted off by the initiation and growth of the cracks. The reasons lead to the fracture
patterns of 3-D closed surface flaw were provided with brittle fracture mechanics theory in the
article, preliminarily.
The Effect of Different Material Parameter Functions in Non-Homogeneous Regions on Eigen-Functions of Crack Tip Fields
Authors: Dai Yao , Zhao Feng Wen , Zheng Zhao Quan , He Jia Wen
Published: March 2009

The effect of different continuous material parameter functions in the non-homogeneous
region on the eigen-functions of crack tip fields is studied by means of the semi-analytical
numerical method based on the wedge shaped non-homogeneous sector model. The cases of the
different opening angles of the non-homogeneous region, the different dissimilar material ratios, the
different configurations, etc. are analyzed systematically. The result shows that the effect becomes
smaller as the opening angle of the wedge shaped non-homogeneous sector becomes smaller. The
valuable conclusion is drawn that the differences among the eigen-functions corresponding to the
cases can be neglected as long as the opening angle is small enough for the engineering application,
which facilitates the engineering application of the non-homogeneous region model.
HA Active Coating on Titanium Prepared by Spark Plasma Sintering
Authors: Zhang Guang Lei , Li Yan Fang , Ren Shu Xia , Zhang Jian Min
Published: March 2009

Hydroxyapatite (HA) active coatings on Titanium were prepared using Spark Plasma
Sintering (SPS). This study focused on the effects of the composition and thickness of coating on its
bonding strength and the fracture appearance. The results showed that the Ti20wt%HA80wt%
coating on Titanium could be well sintered, and bonding strength was improved from 12 MPa to 29
MPa and to 36 MPa along with the reduction of the coat thickness from 0.3mm to 0.2mm and to
0.1mm respectively. When the coating was treated by passivation, the bonding strength of interface
increased largely to 48MPa and 64MPa respectively for HA coating and Ti20wt%HA80wt%
coating on Titanium body, which the HA did not disassemble, and metallurgical combination
between coating and metal was realized at 1180K.
Study on the Carbides and the Interface Bonding in Surfacing Welding Metal
Authors: Zhang Yuan Bin , Shi Yao Wu
Published: March 2009

The interface bonding between the carbides and the solid solution matrix is studied in
surfacing welding metal of Fe-Nb-Ti-V-C alloy system. Both the quenched welding droplets and the
deposited metal are investigated by means of SEM and TEM. In the deposited metal, the carbides
are dispersed, and the matrix is low carbon martensite. According to welding metallurgical
characteristics, it is deduced that the carbides are formed during the droplets stage and then transmit
into the welding pool. When the welding pool solidify, the carbides serve as nucleation site, so the
interface between the carbides and the matrix is clean and free from other reactants. The selected
area electron diffraction (SAED) analysis reveals that the mismatch between the two phase is δ=
(6.1~8.3)%, and there exist a crystal parallel relationship at the interface: (002)α-Fe // (220)(NbTiV)C.
The metallurgical bonding between the carbides and the matrix favors to prevent the carbides to
detach from the matrix during wear process, so the surfacing welding metal can achieve good
wear-resistance.
Study on Surface Metallurgy High Speed Steel Using Double Glow Plasma Technique
Authors: Xu Jin Yong , Gao Yuan , Huang Mei Fa , Cheng Jun , Xu Zhong
Published: March 2009

Mo-Cr diffusion layer on carbon steels are prepared by double glow plasma surface
metallurgy and then treated by ultra-saturated carbonization, quenching and tempering. The content
of component is roughly that of high-speed steels (HSS). The results showed that the depth of
coating is over 100μm and the content of Mo, Cr alloyed layer is about 20% and 10% respectively.
Surface carbon content is over 2.0% after ultra-saturated carbonization. The carbides of the alloyed
layer are fine and dispersed, without coarse eutectic ledeburite. X-ray diffraction showed that the
carbides are M6C, M2C, M23C6 etc. SEM analyse indicated that the dimension of surface carbide is
less 1μm. The abrasion experimental results showed that the relative wear resistance of the treated
sample was 2.38 times as that of quenched GCr15.
Mechanical Properties of Coil Coating Evaluated with Dynamic Mechanical Analysis in Daul Cantilever
Authors: Chen Lei , Pan Hong Liang
Published: March 2009

The storage modulus, loss modulus, loss tangent (tanδ), stress and strain have been
determined for painted steel specimens by dynamic mechanical analysis (DMA) operated in Dual
Cantilever mode. Analysis of the composite system enabled the elastic modulus of the paint layer to
be calculated and the result can be useful to analyze the mechanical properties of the coil coating.
The calculation was found to be very sensitive to the geometry (especially thickness of the substrate
and coating) and properties of the substrate and coating, leading to considerable variability in the
calculated coating modulus. The DMA method was successful in detecting the glass transition
temperature (Tg) as a peak in the tanδ curve. The value of Tg is sensitive to the preparation
conditions (e.g. curing temperature) and composition of the paint. The results show that DMA in
Dual Cantilever can be useful as a characterization tool for painted steel.
Plasma Nitriding Behavior of 1Cr18Ni9Ti Stainless Steel with Nanocrystalline Surface Induced by SMA
Authors: Wu Xiao Chun , Wang Hong Bin
Published: March 2009

The plasma nitriding behaviors of nanocrystalline surface induced by surface mechanical
attrition (SMA) and of conventional coarse-grained surface in 1Cr18Ni9Ti stainless steel were
compared. Microstructure features of various sections in the surface layer, from the matrix to the
nitriding surface, were systematically characterized by XRD, SEM and TEM. The thickness of
compound layer and hardness distribution in the treated surface layer were investigated by means of
metallographic observation and microhardness measurement. The subsequent nitriding kinetics of
the treated steel with the nanostructured surface layer were greatly enhanced, the nitriding thickness
was deeper than that of the conventional surface and the nitriding temperature could be as low as
300°C, which is much lower than conventional nitriding temperature.
Electrochemical Corrosion Behaviors of Ti2AlNb with Double Glow Plasma Surface Molybdenized
Authors: Liang Wen Ping , Xu Zhong , Miao Qiang , He Zhi Yong
Published: March 2009

Ti2AlNb orthorhombic alloy is an attractive high temperature structural material for
aero-industries, but insufficient wear-resistance is a major drawback which restricts the actual uses
of this alloy in many circumstances. A double glow plasma surface molybdenizing on Ti2AlNb
alloy had been carried out to resolve this problem. This paper investigated the electrochemical
corrosion behaviors of the alloy after molybdenizing. The polarization curves of specimens in three
corrosive media, 5% H2SO4, 5% HCl and 3.5% NaCl, were measured. The eroded surface
morphologies were surveyed by SEM. The results indicate that surface molybdenizing decreased
the alloy’s corrosion resistance slightly, but still exhibit good performance.
Molecular Dynamics Simulation of Exit Fracture in the Case of Nanometric Cutting Process
Authors: Han Xue Song
Published: March 2009

Exit fracture, the main factor influencing the precision of workpiece, has already been
extensively studied. In the case of nanometric cutting technology, the depth of cut is in the range of
nanometer or sub-nanometer, there may be some different discipline dominating the exit fracture
generation process. Molecular dynamics (MD) method, which is different from continuous
mechanics, has already played an important role in describing microscopic world. The author
carried out MD simulation of the micro-mechanism of exit fracture generation process, the results
show that different types of burrs is generated depending upon materials ductility and the dimension
of burrs may be increased with the increasing of depth of cut.
Finite Element Study of the Creep Size-Effect in Thin Metal Films
Authors: Niu Li Sha , Dai Ting Ting
Published: March 2009

A 2-D Finite element simulation method was developed based on the kinetic law and the
energy evolution during the whole process of deformation, which is used to investigate the creep size
effects in polycrystalline thin metal film on substrates. Three diffusion paths (e.g. surface, grain
boundary and lattice diffusion) are considered in the present model. The diffusion rate for these three
processes was compared under different loading conditions with corresponding microstructure. It’s
found that grain boundary diffusion is coupled with another diffusion channel. Creep size effects
result from mass transferring in thin film. The model gave the quantitative results of the influences of
the film thickness, grain size, and the constraints of the substrate on polycrystalline metal film
diffusion. The simulated results present the evolution of the point defects in grain interior, the strain
and stress field. The distribution of the crack-like stress in the grain boundary could explain the stress
concentration mechanisms clearly and this also agrees with the literature results.
Effect of Water Height for Modal Characteristics of the Fuel Channel and Stiffness Analysis Using Modal Test Results
Authors: Lee Young Shin , Kim Hyun Soo , Choi Young Jin , Kim Jae Hoon , Yim Jeong Sik
Published: March 2009

A fuel channel, which is the major structure of a nuclear reactor, is excited by the flow of
cooling water during the operation of the nuclear reactor. This flow of cooling water can cause
excessive vibration of the structure by the resonance. So, in the design process of a nuclear structure,
the exact evaluation of the effect of water to modal characteristics and stiffness characteristics is very
important to generate an exact analysis model. In this study, the effect of water height for modal
characterisics of the fuel channel is investigated and the stiffness evaluation of that is conducted using
the modal test results.
Effects of Dynamic Ion Mixing Coating Condition for Fatigue Properties of Stainless Steel with TiN Film
Authors: Fukui Satoshi , Murakami Riichi , Yonekura Daisuke
Published: March 2009

Four point bending fatigue tests were carried out using martensitic stainless steel with TiN
film deposited at five different deposition rates by dynamic ion mixing process in order to investigate
the influence of deposition rate on the fatigue strength. As a result, the fatigue limit clearly increased
by the deposition at appropriate conditions. However, the deposition by other conditions resulted in
the degradation of fatigue strength. This is caused by the decrease of threshold stress intensity factor
after TiN deposition and the difference of defect distribution in the film. In addition, the crack
propagation rate was increased in low stress intensity factor range by the deposition of TiN film.
Study on Sputtering Characteristics of Ni80Cr20 Alloy Target
Authors: He Zhi Yong , Wang Xiao Feng , Fan Ying , Wang Zhen Xia , Liu Xiao Ping , Xu Zhong
Published: March 2009

Sputtering rate Sr was proposed as an alternative parameter instead of sputtering yield Y
to calibrate the sputtering ability of the target, defined as the mass loss of the target per unit time
and sputtering current. The approach is more reliable for glow discharge processes since the intense
backscattering effect was taken into consideration. The effects of processing parameters on Sr were
investigated through orthogonal test, the results indicated that target temperature affects Sr
obviously, and among the discharge parameters, the target voltage and discharge pressure were the
governing factors. Through regression analysis, the sputtering rate Sr was expressed as a function of
sputtering voltage and discharge pressure which could be used to evaluate or predict the real output
of the sputtering target.
Shape Prediction of Fatigue Crack Based on a Given Stress Intensity Factor Distribution
Authors: Wu Zhi Xue
Published: March 2009

There is an inherent relationship between the shape and the corresponding stress intensity
factor (SIF) distribution of a crack. A typical inverse problem of linear elastic fracture mechanics
about a crack, i.e. to predict the shape of a crack assuming that some information of SIF distribution is
known, is presented. A finite-element based numerical procedure is used to determine the shape,
correspondingly the SIF, of a mode-I planar crack based on a specified SIF distribution. The crack
front is modeled using cubic splines, which are determined by a number of control-points. The crack
front shape is achieved iteratively by moving control-points based on a gradientless algorithm.
Numerical examples for planar cracks in through-cracked and surface-cracked plates with finite
thickness and width are presented to show the validity and practicability of the proposed method. The
SIFs obtained by present method are compared with the known solutions for cracks with same
dimensions. The presented method is considered to be a promising alternative to the evaluation of
SIFs and the prediction of shape evolution for fatigue cracks.
Study on Life Prediction Method for Creep-Fatigue Interaction at Elevated Temperature
Authors: Chen Nian Jin , Gao Zeng Liang , Zhang Wei , Le Yue Bao
Published: March 2009

The law of low-cycle fatigue with hold time at elevated temperature is investigated in this
paper. A new life prediction model for the situation of fatigue and creep interaction is developed,
based on the damage due to fatigue and creep. In order to verify the prediction model,
strain-controlled low-cycle fatigue tests at temperature 693K, 823K and 873K and fatigue tests with
various hold time at temperature 823K and 873K for 316L austenitic stainless steel were carried out.
Good agreement is found between the predictions and experimental results.
Development of Diamond-Like Carbon (DLC) Coating Compatible Surface by Fine Particle Bombardment (FPB)
Authors: Kameyama Yutaka , Niwa A. , Komotori Jun
Published: March 2009

To improve adhesion of DLC coatings, Fine Particle Bombardment (FPB) treatment using
Cr based shot particles was performed. After the FPB treatment, DLC coating process was generated
on the Chromium-molybdenum steel. The FPB treatment distributes diffused Cr elements onto the
treated surface, creating a Cr-rich layer. The FPB treatment increases the surface hardness and
roughness which also affect the adhesion of DLC coatings. Wear test was conducted to compare the
tribological properties of the DLC coated FPB treated steels and that of the DLC coated non FPB
treated ones. The DLC coated surface, after FPB treatment, kept low friction coefficient, while the
DLC coated non FPB treated ones showed a sudden increase due to the delamination of DLC layer.
These results imply that delamination of the DLC coating was suppressed by the Cr-rich surface layer
created by the previous FPB treatment. Consequently, the applied method was effective to improve
the adhesion of DLC coatings.
Finite Element Simulation for Residual Stresses in Weling Process
Authors: Yu He , Li Shou Ju , Liu Ying Xi
Published: March 2009

Owing to localized heating by the welding process and subsequent rapid cooling, the
residual stresses can arise in the weld itself and in the base metals. The prediction procedures of the
residual stresses in welding process were presented by using finite element techniques. The bilinear
elastic-plastic material model based on Von Mises yield criterion was developed. The material
non-linearity of weldment and welding fluid was dealt with using an incremental technique. Inside
each step, the Newton-Raphson iteration method was utilized. A fully coupled thermo-mechanical
two-dimensional analysis was performed with finite element method. The model applied in this study
adopts the technique of element birth and death to simulate the weld filler variation with time in
multi-pass welded joints. The effects of welding speed on residual stresses are discussed.
Study on Al Alloy Welded Joint Performance Deterioration under Thermal Cycling Condition
Authors: Jin Cheng , Niu Ji Tai , He Shi Yu , Geng Hong Bin
Published: March 2009

This paper investigates the mechanical performance deterioration of aluminum alloy
welded joints under thermal cycling condition. The real-time temperature, load and strain of the
specimens are monitored during the test. Results show that a long time thermal cycling process can
cause a performance decrease in its plasticity and fracture strength.
Deformation and Fracture Behaviors in the Freestanding APS-TBC - Effects of Process Parameters and Thermal Exposure
Authors: Yamazaki Yasuhiro , Kinebuchi T. , Fukanuma H. , Ohno N. , Kaise K.
Published: March 2009

Thermal barrier coatings (TBCs), that reduce the temperature in the underlying substrate
material, are an essential requirement for the hot section components of industrial gas turbines.
Recently, in order to take full advantage of the potential of the TBC systems, experimental and
analytical investigations in TBC systems have been performed. However there is a little information
on the deformation behavior of the top coating. In addition, the effects of the thermal exposure and
the process parameters on the mechanical properties of the top coating have never been clarified.
From these backgrounds, the effects of the process variables in APS and the thermal exposure on
the mechanical properties were investigated in order to optimize the APS process of top coatings.
The experimental results indicated that the mechanical properties of the APS-TBC, i.e. the tensile
strength and the elastic modulus, were significantly changed by the process variables and the long
term thermal exposure. The microstructural investigation was also carried out and the relationship
between the mechanical properties and the porosity was discussed.
Failure Assessment Diagrams of Semi-Elliptical Surface Crack with Constraint Effect
Authors: Lee Hyung Yil , Lee Jin Haeng , Kim Tae Hyung
Published: March 2009

For accurate failure assessment, a second parameter like T-stress describing the constraint
is needed in addition to the single parameter J-integral. In this work, selecting the structures of
surface-cracked plate and pipe, we perform line-spring finite element modeling, and accompanying
elastic-plastic finite element analyses. We then present a framework, which includes the constraint
effects in the R6 FAD approach for failure assessment of cracked-structures.
Effects of Fiber Layer on Failure Strength Properties of Adhesive - Joined Natural Fiber Reinforced Composites
Authors: Yoon Ho Chel , Lim Jae Kyoo
Published: March 2009

This research was concerned with study of fracture strength of adhesive-lap-joined
composites. The tensile and peel tests were carried out with specimens manufactured hybrid stacked
composites, because the orientation of fiber and the interfacial fracture between the matrix and the
reinforcement had influence on failure strength of composites. Bamboo natural fiber layer was located
between polyester layers. The objective of this study was to evaluate the effect of fiber orientation on
failure strength properties of composites. The test results were presented by load-displacement graph
and finite element analysis. As a result, the load-directional orientation and the thinner thickness of
bamboo natural fiber layer have a good effect on peel and tensile-shear strength and failure shape of
adhesive-joined hybrid stacked composite.
Effects of Resistance Welding on the Failure Strength Properties of Natural Fiber Reinforced Composite
Authors: Yoon Ho Chel , Wang Ren Liang , Dewidar Montasser , Jeon Yang Bae , Choi Jun Yong , Lim Jae Kyoo
Published: March 2009

This research is concerned with a study of failure strength of natural fiber composite.
Tensile-shear tests were carried out with the single-lap resistance welded joined specimens consisting
of composite materials. Composite materials were manufactured using the polyester as a matrix and
bamboo natural fiber layer as a reinforcement. Two types of specimen with different reinforcement
positions were tested to evaluate the failure strength of natural fiber reinforced composite resistance
welded joined specimens. The test results were presented by tensile-shear strength. The failure
mechanism was discussed in order to explain the lower tensile-shear strength of composite and
position of bamboo natural fiber layer on the failure strength properties were explained
Computer Aided Development of the Crack-Free Laser Welding Processes
Authors: Ploshikhin Vasily , Prikhodovski A. , Ilin A. , Heimerdinger C. , Palm F.
Published: March 2009

The present paper describes the new methodology used for the development of the crackfree
welding processes. The presented approach is based on the accurate experimental observations
on binary Al-Si alloys, which clearly demonstrate that the crack initiation is a result of the
accumulation of macroscopic tensile strain in a microscopic intergranular liquid film of segregates
at the final stage of the weld metal solidification. The numerical model takes into account the
effects of strain accumulation as well as the influence of thermo-dynamical and thermo-mechanical
properties of the welded material. The new approach provides a clear phenomenological
interrelation between the cracking susceptibility, parameters of the welding process and properties
of the base and filler material. It is successfully applied for development of technological means for
elimination of the solidification cracking during welding of aluminium alloys AA6056, such as a
multi-beam welding.
Effect of Shot Strip Interval and Shot Times on Laser Shot Peen-Forming with Repetition Laser Pulse
Authors: Yang Chao Jun , Zhang Yong Kang , Zhou Jian Zhong , Ni Ming Yong , Du Jian Jun , Zhang Xing Quan , Zhou Jun , Cao Xiang Guang
Published: March 2009

Laser shot peen-forming of sheet metal(or LasershotSM Peening) is a new plastic forming
technique for metallic materials, which uses high-power pulsed laser replacing the tiny balls to peen
the surface of sheet metal. When the pressure of shock waves induced by laser impresses an
inhomogeneous residual stresses distribution in a given depth on the surface of sheet, it responds to
the stress by elongating at the peened surface and effectively bending the sheet. In order to
investigate the mechanism of laser shot peen-forming, the narrow strip peen-forming experimental
of aluminum alloy 6061-T6 was carried out by using a pulsed Nd:glass laser with 0.5Hz
repetition-rate. Here, under some given laser energy, laser pulse width, laser beam diameter and
pulse repetition frequency and so on, the influence of shot strip interval and shot times on surface
residual stresses and the deformation of the sheet is analyzed. The results show that the bending
forming of the sheet metal can be found, and the peened surface of sheet metal becomes convex.
That the bending increases with shot strip interval increase is not obvious, but it increases with the
shot times increase in a proper range of shot times. Besides, because laser shot peen-forming
generates compressive residual stresses on the surface, it offers many desirable characteristics in
shaped metals and is a valuable technique for producing components for a range of industries.
Modeling of the Temperature Field during Electron Beam Welding of Aluminum Alloy by a Pre-Defined Keyhole
Authors: Tian Yan Hong , Wang Chun Qing , Zhu Dan Yang
Published: March 2009

The transient temperature field of Al alloy during electron beam welding (EBW) process
was simulated using a three-dimensional finite element method. Different from the most previous
models which were based on the assumption that the welding pool was solid and neglected the
existence of keyhole by meshing the solid as a whole, a dynamic three-dimensional keyhole was
applied in this model. The profile of the keyhole was ellipse and its size was determined before
simulation based on the results of experiments. Following the heat source, the pre-defined keyhole
moved along the welding line. A three-dimensional complex heat source model, including a modified
Gaussian distribution source and a uniform source, was used in this study. The result shows that the
shape of the keyhole had a direct effect on the temperature distribution and contribution to the special
shape of the welding pool in EBW.
Synthesis and Characterization of Nanosize Molybdenum Disulfide Particles by Quick Homogeneous Precipitation Method
Authors: Hu Kun Hong , Hu Xian Guo , Sun Xiao Jun , Jing He Feng , Zhan Song
Published: March 2009

Molybdenum sulfide nanoparticles were prepared via quick homogeneous precipitation
method (QHPM) by the reaction between Na2MoO4 and CH3CSNH2 in the presence of sulfuric acid at
80 oC. The as-synthesized molybdenum sulfide particles were studied by X-ray powder diffraction
(XRD), transmission electron microscopy (TEM), and high-resolution transmission electron
microscopy (HRTEM). The results showed that the as-synthesized molybdenum sulfide was
amorphous MoS3 nanoparticles with an average size of 40 nm. The resultant amorphous MoS3
nanoparticles were then calcined under hydrogen gas flow at a selected temperature for 50 minutes.
The results of XRD, TEM, and HRTEM confirmed that the MoS2 nanoparticles with about 40 nm
were prepared from the amorphous MoS3 nanoparticles at 780 oC.
A Study on Concrescence of Inert Nano Bioceramic Scalpel Wounds
Authors: Wang Zhu Ju , Han Wen Bo , Tao Shu Qing , Wu Ying
Published: March 2009

Over the last 100 years innovative techniques in the fabrication of ceramics have led to
their use as high-tech materials. Inert bioceramics, such as ZrO2, have inherently low level of
reactivity compared with other materials such as polymers and metals as well as surface reactive or
resorbable ceramics. The aim of this study was to validate the effect of incision using a zirconia inert
bioceramic scalpel to incise animal body and to prove incision property of tissues before clinic. The
experiments of incisions concrescence using a sterilized Zirconia inert bioceramic scalpel were
investigated in this paper. We used 4-month-old inbred line SD rats as experiment animals. They were
divided into three groups to undergo incision on the back skin and subcutaneous tissue. The
subcutaneous tissue and musculature samples were obtained and analyzed by optical microscopy at 3,
7 and 14 days for histopathological evaluation respectively. The experimental results showed that no
wound dehiscence was observed after suture removal at 14 days after the operation. The experiments
proved that an inert bioceramic scapel was nontoxic, nonallergenic, and noncarcinogenic for incisions
that obtained normal concrescence criteria two weeks after operation.
Preparation and Performance under Corrosive Environment of Epoxy-Nanocomposite
Authors: Abacha N. , Kubouchi M. , Tsuda K. , Sakai T.
Published: March 2009

Epoxy-organoclay nanocomposite were prepared and investigated in terms of mechanical
properties and also in term of water diffusion and sulfuric acid corrosion resistance. Diffusion was
studied through epoxy samples containing up to 6phr of organically treated montmorillonite. The
diffusion of the environmental solution was measured by immersion of the samples in these
solutions at elevated temperature with noting the increase in weight as immersion function of time.
An evaluation by flexural strength of the nanoclay/epoxy composites samples was made to
compare their mechanical performances under corrosive environment as a function of immersion
time and temperature.
Compressive Instability of Carbon Nanotubes
Authors: Hu Ning , Nunoya Kazuhiko , Fukunaga Hisao
Published: March 2009

Based on both molecular mechanics and computational structural mechanics, a
three-dimensional (3D) equivalent beam element is developed to model a C-C covalent bond on
carbon nanotubes (CNTs) whereas the van der Waals forces between atoms in the different walls of
multi-walled CNTs are described using a rod element. The buckling characteristics of CNTs are
conveniently analyzed by using the traditional finite element method (FEM) of a 3D beam and rod
model, termed as molecular structural mechanics approach (MSMA). Moreover, to model the CNTs
with large length or large diameter, the validity of Euler’s beam buckling theory and a shell model
with proper properties defined from the results of MSMA is investigated. The predicted results by
this simple continuum mechanics approach agree well with the reported experimental data.
Mineralization of Chitosan via Alternate Soaking
Authors: Li Bao Qiang , Guo Ya Ping , Huang Ke , Jia De Chang , Zhou Yu , Cai Wei
Published: March 2009

Hydroxyapatite coating was prepared by alternate soaking strategy in short period time and
ambient condition. According to the pH near equality between chitosan acidic acid solution and
H2PO4
- aqueous solution, we proposed to choose H2PO4
- as one of hydroxyapatite precursor instead of
traditional candidate (HPO4
2-). The properties of chitosan hydrogel containing plenty of water provide
enough spaces for hydroxyapatite precursor to diffuse into framework spontaneously. XRD, FTIR and
SEM were used to characterize the component and microstructure of mineralized chitosan. The
ageing process helps to transfer amorphous calcium phosphate in chitosan framework into
hydroxyapatite. The hydroxyapatite coating is gradient structure according to the result of SEM.
Evaluation of Fatigue Transverse Cracking Behavior by Cooperation of Sliding Core and Endplate in Artificial Intervertebral Disc
Authors: Kim Cheol Woong , Kang Bong Su , Kim Kee Joo , Lee Jin Yi
Published: March 2009

The research of the stress distributions and the structural deformation at the sliding core
in artificial intervertebral disc under the dorsiflexion is becoming more significant. This research
analyzes the finite element model of sliding core and evaluates the effect of radius of curvature and
the friction coefficient at the sliding core on von-Mises stress and the contact pressure. New Models
of the artificial intervertebral disc are suggested by the results of the sliding core is evaluated by the
comparison of that of SB Charité III. Based on the above facts, the optimized radius of curvature of
the sliding core is also suggested.
Adhesion Test of Nanostructured Materials by a Novel AFM Probe
Authors: Lee Hak Joo , Kim Jae Hyun , Cho Ki Ho , Hyun Seung Min , Kim Jung Yup , Yoo Young Eun , Kim Wan Doo
Published: March 2009

We have developed a novel atomic force microscope (AFM) probe as a highly sensitive
sensor and an application of the probe into various mechanical tests for characterizing micro/nanostructures.
Using MEMS fabrication technique, we have designed and fabricated rhombus-shaped
symmetric AFM probe. Adhesion forces between silicon tip and artificial nano-hair structures of
cyclic olefin copolymer (COC) and polypropylene (PP) were measured using the probe with a flat
tip. The results exhibited the usual characteristics of force-displacement curves of COC and PP
nano-hair structures, in which a pull-off force was detected at the point of unloading. The average
adhesion forces of the COC and PP hair structures are about 9.48 μN and 10.67 μN, respectively.
Nanomechanical Properties of Tooth and Bone Revealed by Nanoindentation and AFM
Authors: Cui Fu Zhai , Chen Zhen Jiang , Ge Jun
Published: March 2009

In this paper, an overview on nanoindentation and its combination with AFM is
presented with regard to current instrument technology and applications on dental and bony tissues.
Nanoindentation has been a widely used technique to determine the mechanical properties such as
nanohardness and Young’s modulus for nanostructured materials. Especially, atomic force
microscopy (AFM) combined with nanoindentation, with the pit positions controlled accurately,
become a powerful technique used to measure mechanical properties of materials on the nanoscale,
and has been applied to the study of biological hard tissues, such as bone and tooth. Examples will
be shown that significantly different nanohardness and modulus in the isolated domains within
single enamel, the prisms, interprisms, the surrounding sheaths and the different parts of skeletal
bone, could been distinguished, while such information was unable to be obtained by traditional
methods of mechanical measurements.
Damage Detection Based on the Cross Correlation Function Amplitude Vector and its Application to the ASCE Benchmark Structure
Authors: Yu Zhe Feng , Yang Zhi Chun
Published: March 2009

A new method for structural damage detection based on the Cross Correlation Function
Amplitude Vector (CorV) of the measured vibration responses is presented. Under a stationary
random excitation with a specific frequency spectrum, the CorV of the structure only depends on the
frequency response function matrix of the structure, so the normalized CorV has a specific shape.
Thus the damage can be detected and located with the correlativity and the relative difference between
CorVs of the intact and damaged structures. With the benchmark problem sponsored by ASCE Task
Group on Structural Health Monitoring, the CorV is proved an effective approach to detecting the
damage in structures subject to random excitations.
Non-Destructive Evaluation of a Delamination in Laminates by Lamb Wave Propagation
Authors: Qian Zheng Hua , Jin Feng , Wang Zi Kun , Kishimoto Kikuo
Published: March 2009

The diffraction of Lamb waves by a finite delamination situated on a random plane parallel
to the symmetric plane of a laminated plate is taken into account. Two imaginary planes are
introduced to solve the problem by adopting the method of mode matching. By taking an appropriate
finite number of terms of the infinite expansion series and some selected points on the two imaginary
planes through convergence and precision tests, a matrix equation is obtained to evaluate the
expansion coefficients numerically. Reflection coefficients versus the normalized length a/h and the
relative location h1/h of the delamination are calculated in the low-frequency domain, the relative
errors are found to be less than 1%. Results obtained indicate that the theory developed in this paper is
meaningful for the detection of both the size and the location of a delamination in a laminated plate by
cooperating with experimental techniques for the non-destructive evaluation (NDE) technology.
Quantitative Evaluation of Cracks under Water by Microwaves
Authors: Ju Yang , Miyadu Toru , Soyama Hitoshi , Saka Masumi
Published: March 2009

Quantitative evaluation of small cracks in stainless steel under water, which simulated the
environment of unclear reactor, by using microwave, was demonstrated. The crack depth was
evaluated by means of the microwave dual frequency technique, and the crack closure stress was
estimated based on the compliance technique.
A Study on the Vibration Characteristics of Symmetry and Asymmetry Laminated Composite Materials by Using ESPI
Authors: Hong Kyung Min , Kang Young June , Park Nak Kyu , Ryu Weon Jae
Published: March 2009

The ESPI (Electronic Speckle Pattern Interferometry) is a real-time, full-field,
non-destructive optical measurement technique. In this study, ESPI was proposed for the purpose of
vibration analysis for new and composite materials. Composite materials have various complicated
characteristics according to the materials, orientations, stacking sequences of the ply and boundary
conditions. Therefore, it was difficult to analyze composite materials. For efficient use of composite
materials in engineering applications the dynamic behavior (i.e., natural frequencies and nodal
patterns) should be informed. With the use of Time-Average ESPI, one could analyze vibration
characteristics of composite material by real time easily. We manufactured two kinds of laminated
composites (i.e., symmetry and asymmetry) which were consisted of CFRP (Carbon Fiber
Reinforced Plastics) and the shape of the test piece was of rectangular form.
In Situ X-Ray Stress Measurement in Electrodeposited Cu Foils under Tensile and Fatigue Loading
Authors: Akiniwa Yoshiaki , Suzuki Tsuyoshi , Tanaka K.
Published: March 2009

Monotonic and cyclic loadings were subjected to electrodeposited copper foils (thickness is
8 and 20 μm), and the deformation behavior was observed. In-situ X-ray stress measurement was
carried out under monotonic loading. The tensile strength of 8 μm foil was higher than that of 20 μm
foil. On the other hand, the elongation of 8 μm foil was smaller. When the plastic deformation
occurred, difference between the X-ray stress and the applied stress became large. The difference of
20 μm foil was larger than that of 8 μm foil. Fatigue strength of 8 μm foil was also higher than that of
20 μm foil. The value of the full width at half maximum, FWHM, increased dramatically at the first
cycle, and then the value became nearly constant. Just before fracture, the value increased again. The
change in FWHM corresponded to the change in the accumulated ratchet strain.
Fatigue Damage Accumulation of Welded Bridge Member during Crack Growth Propagation with Initial Crack
Authors: Zhou Tai Quan , Chan Tommy Hung Tin
Published: March 2009

The crack growth behavior and the fatigue life of welded members with initial crack in
bridges under traffic loading were investigated. Based on existed fatigue experiment results of
welded members with initial crack and the fatigue experiment result of welded bridge member
under constant stress cycle, the crack keeps semi-elliptical shape with variable ratio of a/c during
crack propagation. The calculated method of the stress intensity factor necessary for welded bridge
member crack propagation was discussed. The crack remained semi-elliptical shape with variable
ratio of a/c during crack propagation. The fatigue crack propagation law suitable for welded steel
bridge member fatigue crack propagation analysis was deduced based on the continuum damage
mechanics and fracture mechanics. The proposed fatigue crack growth model was then applied to
calculate the crack growth and the fatigue life of existed welded member with fatigue experimental
result. The calculated and measured fatigue life was generally in good agreement, at suitable initial
conditions of cracking, for welded member widely used in steel bridges.