bluuebunny/crossref_metadata_2025 huggingface dataset:
A Study of Osteocalcin Production In Vitro on Various Hydroxyapatite Based Biomaterials
Authors: Xu J.L. , Khor Khiam Aik , Chen W.N.
Published: March 2009

Hydroxyapatite based biomaterials were prepared by a spark plasma sintering
technology. The human limb-derived osteoblasts were cultured on the various biomaterial surfaces
(HA, RF21, 1SiHA and 5SiHA) for up to two weeks to investigate the cellular behaviors. The bone
gammacarboxyglutamic protein or osteocalcin in the medium were determined at different periods
of cell culture. The results indicated that a combined effect of bioceramic surface composition and
surface morphology had influenced the osteoblast behaviors. The amount of osteocalcin in the
medium increased in the initial periods of culture but decreased in the late periods of culture.
Two Dimensional Histogram of X-Ray Microtomogrpahy and Its Application in Quantification of Ex Vivo Implants
Authors: Zou Shuo , Brooks Roger A. , Best Serena , Buckland Tom , Fu Xiao Wei , Rushton Neil , Bonfield William
Published: March 2009

Computerized X-ray microtomography (micro CT) is a powerful technique for imaging
and quantification in biomedical materials research. Mapping of various tissue/implants in
3-dimension, which is not achievable with traditional histological slices, is particularly desirable in
ex-vivo implant analysis. However, due to a variety of artifacts during image formation, especially
the blurred interfaces due to the machine contrast transfer function and the partial volume effect,
quantification based on traditional histograms is not accurate. In this work we propose a new
2-dimensional histogram and its application in the analysis of micro CT data of ex-vivo implants,
which significantly improve the clarity of the definition of different phases and drastically reduced
the artifacts of segmentation compared to conventional methods.
Degradation of Surface Modified β-TCP/PLLA Porous Scaffold In Vitro
Authors: Zhang Yun , Yin Guang Fu , Wang Yue Hua , Yang Wei Zhong , Kang Yun Qing
Published: March 2009

Degradation of surface modified β-tricalcium phosphate (β-TCP) and poly L lactic acid (PLLA) composite scaffolds were investigated in vitro. Bending and compressive strengths were tested by electromechanical universal material testing machine. Molecular weight changes of lactic acid during degradation were measured by gel permeation chromatography (GPC). Phase composition of the surface after soaking was analyzed by Fourier transform infrared ray (FTIR). The surface and cross section of scaffold samples after degradation were observed by Scanning electron microscope (SEM).The results show that degradation speed can be controlled by adjusting the ratio of β-TCP to PLLA in the composite. PLLA can compound more closely with surface modified β-TCP than with non-modified one. The final compressive strength and bending strength of the scaffolds reach 7.11MPa and 2.20MPa respectively, which satisfies the need for bone tissue engineering scaffolds in clinic applications.
Study on Hydroxylapatite Fibroin Porous Composite
Authors: Lu Shen Zhou , Li Ming Zhong , Bai Lun
Published: March 2009

The complex porous materials, Hydroxyapatite(HA)/silk fibroin, were prepared using ultrasonic vibration gel method in this paper. The mechanical properties decreased with the increase of HA while the porosity increased. The pore size become bigger than 100μm when adding silk fiber in the complex materials, and the breaking energy increased evidently from 10 to 1000 J/m2 when fiber content increased from 0 to 4 wt.%. It was observed from SEM that all composites have interconnected micropores.
Comparison among Four Kinds of Bone Tissue Engineering Scaffold
Authors: Liu Lei , Chen Run Liang , Lin Yun Feng , Li Cai , Tian Wei Dong , Li Sheng Wei
Published: March 2009

Bone tissue engineering is a promising way to repair of bone defects. To choose a proper scaffold is still a disputable problem in bone tissue engineering. This study aimed to compare the effects of repairing critical calvarial defects with the compounds of autogenous bone marrow stromal cells (BMSCs) and coral hydroxyapatite(CHA), hydroxyapatite/ tricalcium phosphate (HA/TCP), poly(lactide-co-glycolide) (PLGA) and alginate (AG). The results showed that CHA and AG were satisfactory bone tissues engineering scaffolds among the four kinds of materials. BMSCs/CHA and BMSCs/AG are promising techniques for reconstruction of bone defects.
Microstructure and Properties of A Calcium Phosphate Cement Tissue Engineering Scaffold Modified with Collagen and Chitosan
Authors: Wang Xiu Peng , Ye Jian Dong , Chen Ling , Wang Ying Jun
Published: March 2009

In this study, an ACP-DCPD based Calcium phosphate cement (CPC) scaffold with a
porosity of 88% was prepared by using Na3PO4 as a poregen and then modified by collagen and
chitosan. The results showed that collagen and chitosan obviously increased the compressive
strength. Cell culture showed that the cell can migrate, attach, proliferate and differentiate on the
surface of the materials and the pores walls. This CPC scaffold modified with collagen or chitosan
was a promising material to be used in bone tissue engineering.
Stress and Crack Extension in Multi-Layered Ceramic Composites
Authors: Lange Frederick F.
Published: March 2009

It has been demonstrated, through theory and experiments, that compressive layers arrest large surface and internal cracks to produce a stress below which the material will not fail. This enables the materials to have a Threshold Strength. The stress intensity function, K, was derived for a crack sandwiched between two compressive layers. This function suggests that the threshold strength is proportional to the magnitude of the residual, compressive stress, the thickness of the compressive region, and inversely proportional to the distance between the compressive regions. All of these factors have been experimentally examined for laminar composites containing thin, compressive layers. Cracks that propagate straight though the layer obey the K function used to model this behavior. Crack bifurcation, which occurs at high compressive stresses, produces a larger threshold strength than predicted. Crack bifurcation is not fully understood. During the initial studies, differential thermal contraction during cooling from the densification temperature was used to develop the compressive stresses. A molar volume change to induce the compressive stress was also used to develop the compressive stresses. In one case, it was shown that the compressive stresses could arise when the compressive layer contained a material that underwent a structural phase transformation during cooling. In another, ion exchanged glass plates that are subsequently bonded together also produce a threshold strength. Factors that affect the threshold strength are reviewed.
Influence of the Cone Crack Geometry on the Strength Degradation
Authors: Ceseracciu Luca , Anglada Marc , Jiménez-Piqué Emilio
Published: March 2009

The presence of surface compressive residual stress in a laminated material enhance the resistance of the component by reducing the stress intensity factors acting on the cracks -either natural or artificial- existing in the surface. Fissures in the form of cone crack are often generated by blunt contact in service, that can affect the functionality as well as the strength of the material. In this work, a two-steps analysis of the effect of residual stresses on the geometry of cone crack and how this change in geometry influences the far-field strength of the material was performed by means of a Finite Elements model and of experimental observations. In the first part, an automatic incremental model was formulated, which allowed to establish the crack shapes that were used in the second part for simple four-points test models. It was observed that residual stresses change considerably the crack shape, with important implications in the design of contact-damage tolerance, and that this reflects on corresponding changes in the strength.
Modelling of Crack Growth Near the Metallic-Ceramic Interface during Thermal Cycling of Air Plasma Sprayed Thermal Barrier Coatings
Authors: Casu A. , Marqués J.L. , Vaßen Robert , Stöver Detlev
Published: March 2009

The lifetime under thermal cycling of a system consisting of an air plasma sprayed
thermal barrier coating (TBC) deposited on a metallic bondcoat (BC) is determined by the subcritical
growth of micro-cracks near the interface between both coatings. This growth mainly occurs
during the cooling down phase, as shown by the acoustic emission monitoring during the thermal
cycling. The factors controlling the stress level leading to the crack growth are the local curvature
of the metallic-ceramic interface, the growth of an oxide scale (TGO) at such interface and the
sintering of the TBC, the two last processes occurring during the high temperature cycle phase.
Implementing all these factors, a model based on Finite Element Method (FEM) calculations is
presented where growing cracks are incorporated by assigning soft properties to the FEM cells
occupied by the cracks. Determining the growth direction for the maximum energy release rate at
every cooling down step, the current crack extension during the cycling is tracked until it reaches a
characteristic length corresponding to the TBC failure. The influence by the metallic-ceramic
interface roughness and by the temperature gradient across the TBC is discussed.
Dyeing and Finishing Effluent Treatment with Chitosan/Inorganic Composites
Authors: Zhang Yi He , Szeto Yau Shan , Ke Shao Jian , Tan Wei , Liao Li Bing
Published: March 2009

In recent years, chitosan/inorganic composites have attracted increasing attention due to
its fascinating properties and potential applications in biodegradable materials, drug release,
electrochemical sensor, packaging materials and so on. Chitosan/inorganic composites are expected
to be as an effective way to overcome shortcomings of slow flocculating speed of chitosan particles,
not good enough to meet those wide range of applications in wasterwater treatment. In this study,
novel chitosan/clay/PAC (polyaluminium chloride) composite was prepared, and it was used in
treating effluent from dying and finishing process. One set of orthogonal experiments were
conducted to optimize the experimental condition, and the results showed that removal of waste dye
is affected by the dosage of chitosan, PAC, clay, pH and treatment time. The experiments results
indicated that the effluent from dying and finishing process treated by the prepared composites
became obviously fade, and its COD (chemical oxygen demand) decreased from original
1398.2mg/L to 197.6mg/L, the removing rate reached 85.9%.
Micromagnetic Simulation of Size Effects on the Properties of Ferromagnetic Materials
Authors: Hu Ra Loon , Soh Ai Kah
Published: March 2009

Micromagnetic simulation was carried out to investigate the behavior of ferromagnetic
materials at a very small length scale, at which the materials usually exhibit different properties
compared with those of the corresponding bulk materials. By solving the time and spatial dependent
Landau-Lifshitz-Gilbert (LLG) equation in reciprocal space using fast Fourier transformation (FFT)
technique, the equilibrium magnetization state was, thus, achieved. The hysteresis loops were also
simulated, from which the relation of coercivity and characteristic length was established. Besides,
the effect of external stress on coercivity was also taken into consideration. The results showed that
at such length scales the external stress strongly affected the magnetic behavior of ferromagnetic
materials.
Static Behaviours of Carbon Fibre Composite Strip with Bifurcated Type Shape Memory Alloy Pins
Authors: Chan Kuen Cheong , Zhou Li Min
Published: March 2009

A numerical study of the static behaviours of composite strip with bifurcated type shape
memory alloy pins has been conducted. The case of bifurcated type shape memory alloy pins
inserted inside the composite strip around the hole to reinforce the laminate, which was subjected to
the axial stress was simulated. The models for stress analysis were established by using ANSYS
finite element programme. Two types of shape memory alloy pins were proposed to insert along the
through thickness direction of the carbon fibre woven fabric composite strip to induce the clamping
force. The pre-tensioned load was applied to the shape memory alloy pins in order to reduce
occurrence of delamination in the laminate. Three-dimensional elements and contact elements were
used to simulate the contact between the composite laminate and shape memory alloy pin to
investigate the stress distribution around the hole in the composite strip. The effect of pre-strain of
shape memory alloy on the stresses inside composite was studied. The results show that the stress
characteristics of the button-shaped and bifurcated shape memory alloy pin models are similar;
however, the stresses for the button-shaped pin model are lower. The tensile and compressive
stresses, both in button-shaped and bifurcated pin models, are strongly dependent on the percentage
of pre-strain of the shape memory alloy. It is therefore concluded that the shape memory alloy pin
method was significantly reduced the stress concentration of the composite strip laminate.
On Bainite Nucleation at Carbon Depleted Zone around Edge Dislocation
Authors: Zhao Si Xin , Wang Wei , Mao Da Li
Published: March 2009

The maximum number of carbon atoms adsorbed at edge dislocation was calculated
using a model based on Boltzmann distribution. The number of carbon atoms adsorbed by edge
dislocation increases with bulk concentration increasing and temperature decreasing. When the
interfacial energy was chosen as 0.2J/mol, the maximum radius of carbon depleted zone is smaller
than the critical radius required for displacive nucleation at 700K, however, larger than the critical
radius at 600K. Moreover, the radius of carbon depleted zone around the dislocation at 600K is
larger than that at 700K. It seems that bainite may nucleate by a displacive mechanism at lower
temperature.
Fabrication and Characterisation of Polymer and Composite Scaffolds Based on Polyhydroxybutyrate and Polyhydroxybutyrate-Co-Hydroxyvalerate
Authors: Sultana Naznin , Wang Min
Published: March 2009

This paper reports the fabrication and characterization of three-dimensional, highly porous
polyhydroxybutyrate (PHB), polyhydroxybutyrate-co-valerate (PHBV) and composite scaffolds
made by the emulsion freezing / freezing-drying technique. Freeze-drying of the polymer/solvent/
water phase emulsions produced hard and tough scaffolds with interconnected pores. The effects of
the fabrication parameters such as polymer concentration in emulsions and emulsion stabilizer were
examined and optimized. The density of polymer scaffolds was found to increase with an increasing
polymer concentration. Structural analyses of selected samples using scanning electron microscopy
indicated that the scaffolds had pore sizes ranging from several microns to a few hundred microns.
The porosity of scaffolds of up to 85% was achieved and it increased with a decreasing polymer
concentration. It was found that mechanical properties of composite scaffolds increased with the
increasing amount of hydroxyapatite (HA) incorporated in the scaffolds.
Bioactive Composite Coating on Titanium Implants for Hard Tissue Repair
Authors: Wu Jin Ming , Wang Min , Osaka Akiyoshi
Published: March 2009

A bioactive composite coating consisting of one layer of titania and one layer of apatite
was formed on Ti substrate. The first layer of crystalline titania was deposited on Ti at low
temperatures either through oxidation of Ti by hydrogen peroxide solution or through hydrolysis of
TiF4 or TiCl4 solution. It was shown that the crystalline titania, either in the form of anatase or rutile,
induced formation of the second layer of apatite in a simulated body fluid. However, the trace
elements in the titania layer affected greatly apatite formation. The Cl incorporated in the titania
layer did not hinder apatite formation while F did. The two-layer composite coating should enhance
bonding of Ti implants to bone tissue.
Study on the Mechanical Properties of Tissue-Mimicking Phantom Composites Using Ultrasound Indentation
Authors: Ling Hang Yin , Choi P. Carrie , Zheng Y.P. , Lau Alan Kin Tak
Published: March 2009

This paper demonstrates the use of ultrasound (US) indentation technique for
estimating the mechanical properties of tissue- mimicking phantom composites. A
tissue-mimicking phantom composite is used to simulate two-layer soft tissue in human.
Investigation on the mechanical properties of the phantom composites is extremely important for
the understanding of the viscoelastic behaviours of soft tissues and the validation of our proposed
US indentation system. The hand-held indentation probe embedded with a US transducer and a
load cell together with a US pulser/ receiver. The output of the whole indentation process can be
illustrated as force-deformation curves. The mechanical properties of the phantom composites
can be estimated by analyzing the force-deformation curves using genetic algorithm (GA).
The Dynamic Fracture Analysis of the Adhesively Bonded Materials under Shear Loading
Authors: Cai Yan Hong , Chen Hao Ran
Published: March 2009

The dynamic stress intensity factor was studied about the Griffith crack between the
visco-elastic layer and elastic body under shear loading. Adopting integral transform and singular
integral equation method, the time response of dynamic stress intensity factor was calculated.
Considering the influence of materials parameter, it was found that the dynamic stress intensity
factor increases with crack length increasing, and it posses distinct size effect when the thickness of
visco-elastic layer reaching the character size of materials.
Fabrication and Characteristics of Carbon Fiber Reinforced C–SiC Dual Matrix Composites
Authors: Zhu Dong Mei , Luo Fa , Du Hong Na , Zhou Wan Cheng
Published: March 2009

A series of carbon fiber reinforced C-SiC dual matrix composites (C/C-SiC composites)
were developed through precursor infiltration of polycarbosilane (PCS) and pyrolysis (PIP), using
porous C/C composites with different density from chemical vapor infiltration (CVI) as the
preform. The density, mechanical properties, and microstructure of the composites were
investigated and the effects of the preform density and the PCS concentration of the infiltration
solution on the final density and the mechanical properties of the composites were discussed in
detail. The results show that the final density of the C/C-SiC composites prepared at the infiltration
concentration of 50% is the highest, indicating that 50% is the proper PCS concentration of the
PCS/ Xylene solution to prepare the C/C-SiC composites. The final densities of C/C-SiC composites
were closely related to the preform density and the highest final density corresponds to the highest
original preform density. For the composites prepared using infiltration solution of 50% PCS, the
C/C-SiC composite whose preform density is 1.23 g/cm3 possesses the best mechanical properties
while that whose preform density is 1.49 g/cm3 the worst mechanical properties.
Nonlinear Analysis of the In-Plane Young’s Moduli of Two-Dimensional Cellular Materials with Negative Poisson’s Ratios
Authors: Wan Hui , Hu Zhen Yu , Bao Wu Jun , Hu Guo Ming
Published: March 2009

This study deals with the in-plane Young’s moduli of two-dimensional auxetic cellular
materials with negative Poisson’s ratios. The in-plane Young’s moduli of these cellular materials are
theoretically analyzed, and calculated from the cell member bending with large deflection.
Expressions for the in-plane Young’s moduli of the above-mentioned cellular materials are given by
incomplete elliptic integrals. It is found that the in-plane Young’s moduli of two-dimensional cellular
materials with negative Poisson’s ratios depend both on the geometry of the cell, and on the induced
strain of these cellular materials. The in-plane Young’s moduli are no longer constants at large
deformation. But at the limit of small strain, they converge to the results predicted by the small
deformation model of flexure.
In Situ Formation of Poly(ethylene naphthalate) Microfibres in Polyethylene and Polypropylene during Extrusion
Authors: Leung Ka Lok , Easteal Allan J. , Bhattacharyya Debes
Published: March 2009

Tensile properties and morphology of poly(ethylene naphthalate)/polyolefin blends and
the relationship with the extrusion die size were investigated. Scanning electron micrographs of
the blends reveal that the fibre morphology is developed during extrusion through the die.
Skin-core morphology has been observed. As die diameter decreases, a droplet-to-fibre transition
in morphology increases tensile strength and stiffness. After microfibrillization, up to 100%
increase in the tensile stiffness was observed and the tensile strength could increase by one order of
magnitude.
Influence of Cr Particle Size on the Microstructure and Electrical Properties of CuW60Cr15 Composites
Authors: Xiao Peng , Liang Shu Hua , Zhao Wei Bing , Fan Zhi Kang
Published: March 2009

A series of CuW60Cr15 composites with different Cr particle size ranging from 43μm
to147μm in diameter have been prepared by infiltration. The results show that the size of Cr
particles plays an important role on the microstructures and the properties of the CuW60Cr15
composite. Fine Cr particle changes not only the size of the isolated CrCu alloy zone but also the
structure of the skeletons of the composite obviously. Fine Cr particles increase not only the
maximum and the minimum but also the mean value of breakdown voltage. Although the maximum
value of chopping currents remains almost constant while Cr particles become finer, the minimum
and the mean values of chopping current discernible decrease in the CuW60Cr15 composites. It can
be seen from the SEM photos of the composites after arcing that the size and its location of the arc
spot determines the chopping current value of the composites.
Postbuckling Failure Behaviours of Hat-Stiffened Composite Panels with Different Bonding Methods
Authors: Kim K.S. , Yoo J.S. , An Jae Mo , Jang Young Soon , Yi Yeong Moo , Cho Gwang Rae
Published: March 2009

Postbuckling failure behaviors and strength were investigated in compression tests of the
hat stiffened composite panels manufactured with different bonding methods and different stiffener
section shapes. The skin-stiffener separation loads, separation failure behaviors and final collapse
loads were different with respect to bonding methods and stiffener shapes. As the separation failure
was initiated early and propagated larger area, collapse loads and structural performance of the panels
decreased. The test results showed that the co-curing with or without adhesive film and open type
stiffeners were most beneficial for the postbuckling strength.
Abrasive Wear and Aluminium Sticking Resistance of Steel Matrix Composites
Authors: Lou De Chun , Solberg Jan K. , Akselsen Odd Magne , Dahl Nina
Published: March 2009

In this paper, new steel matrix composites have been developed by powder metallurgy/HIP
and abrasive wear and aluminum sticking resistance of the materials have been investigated. The
microstructure examination showed that Co-coated WC reinforcement was partly dissolved in a high
speed steel (HSS) matrix and an interface layer of M6C formed, but both Co-coated WC and NbC
reinforcements were stable in a high vanadium tool steel (CPM10V) matrix. The NbC reinforcement
was also stable in a HSS matrix at the same HIP parameters. Property test results indicate that
Co-coated WC-reinforced composites have higher abrasion resistance than the composites with NbC,
but the latter possess the lowest aluminum sticking propensity. Compared with unreinforced alloys,
abrasion wear resistance of the composites was increased by a factor of 3 to 10, most for the
HSS-matrix composites.
Numerical Simulation of Unidirectional Hoop Composite Laminates under Flexural Loads
Authors: Tong Li Li , Wang Zhen Qing , Sun Bao Hua
Published: March 2009

Numerical simulation for unidirectional hoop composite laminates under flexural loads
was finished. The change of tensile and compressive stresses, the position of local crush and
delamination and stiffness degradation were analyzed with parametric program compiled by APDL
language in ANSYS. The results showed that composite laminate could bear the load continually
after local crush and delamination. Displacements of calculated result with stiffness degradation
model matched test results well.
Modelling of Thermal Cracking Behaviours of Fiber-Reinforced Composites
Authors: Xu Tao , Wang Shan Yong , Tang Chun An , Song Li , Tang Shi Bin
Published: March 2009

In this paper, a coupled thermal-mechanical-damage model, Material Failure Process
Analysis for Thermo code (abbreviated as MFPA-thermo), was applied to investigate the formation,
extension and coalescence of cracks in FRCs, caused by the thermal mismatch of the matrix and the
particles under uniform temperature variations. The effects of the thermal mismatch between the
matrix and fibers on the stress distribution and crack development were also numerically studied. The
influences of the material heterogeneity, the failure patterns of FRCs at varied temperatures are
simulated and compared with the experimental results in the present paper. The results show that the
mechanisms of thermal damage and fracture of the composite remarkedably depend on the difference
between the coefficients of thermal expansion of the fibers and the matrix on a meso-scale.
Meanwhile, the simulations indicate that the thermal cracking of the FRCs at uniform varied
temperatures is an evolution process from diffused damage, nucleation, and finally linkage of cracks.
Ti-Based Nanostructure Coating on Mg Alloys
Authors: Chiu Y.L. , So V. , Li Zheng Wei
Published: March 2009

In this work, we report our study of the microstructure and mechanical properties of pure
Ti, Ti-11Al, Ti-47Al and Ti-6Al-4V nanostructure coatings on AZ91D Mg alloys prepared using DC
magnetron sputtering. The fine structures of the coating (see fig. 1 for Ti-6Al-4V coating) are
presented. The hardness of the coatings were tested on a CSEM nano-hardness tester with a
Berkovich diamond intender. Hardness values were obtained from analyses using the Oliver-Pharr
scheme. The hardness of the nanostructure coating increases from about 3.5GPa up to about 6.8GPa
when the aluminium concentration increases from zero to 47at.%. Maximum hardness value was
found on the Ti-6Al-4V coating, about 7.3GPa. The elastic modulus of the pure Ti coating has the
lowest modulus and strain burst “pop-in” has been observed on Ti-47Al coating.
Fabrication of Magnetic Iron-Hercynite Composites by Reaction Sintering
Authors: Chung K.C. , Ng Dickon H.L.
Published: March 2009

Iron-hercynite composite was synthesized from Al and Fe3O4 powders by reaction sintering
at ~1350oC, or by arc-melting. In reaction sintering, a three-step displacement reaction between Al
and Fe3O4 was identified. In arc-melting, we observed that molten iron and hercynite segregated from
each other readily. Magnetization of the extracted hercynite from the arc-melted sample was 4 emu/g,
smaller than those previously reported, and this can be explained by the variations of the
stoichiometric ratio and the degree of inversion of the spinel structure in the hercynite products.
Microstructure and Mechanical Properties of Copper Clad Aluminium Wire by Drawing at Room Temperature
Authors: Ma Yong Qing , Wu Yun Zhong , Gao Hong Tao , Zhang Yang , Liu Shi Yong
Published: March 2009

The microstructure and mechanical properties of pure copper clad Aluminum wires in
different diameters by drawing at room temperature were studied in this paper. The results show that
the microstructure of the cladding wire by drawing at room temperature is vimineous grain as fibril
shape from prime equiaxed grain. The fibril diameter is in inverse proportion to deformation and the
fibril length is in direct proportion to square of deformation approximately. The ultimate tensile
strength of the cladding wire by drawing at room temperature increases in direct proportion to square
root of deformation, and the elongation decreases and fluctuates. Basis of the ultimate tensile
strength of prime pure copper and aluminum alloy, the ultimate tensile strength of the cladding wires
in different diameters can be doped out by mixed principle of composite material.
An Improved Shear-Lag Model for a Single Fiber Composite with a Ductile Matrix
Authors: Kimura Souta , Koyanagi Jun , Hama Takayuki , Kawada Hiroyuki
Published: March 2009

A shear-lag model is developed to predict the stress distributions in and around an isolated
fiber in a single-fiber polymer matrix composite (PMC) subjected to uniaxial tensile loading and
unloading along the fiber direction. The matrix is assumed to be an elasto-plastic material that
deforms according to J2 flow theory. The stress distributions are obtained numerically and compared
with a different shear-lag model that employs total strain theory as a constitutive equation of the
matrix material. An effect of the difference between the models on the derived stress state is
discussed.
Fracture Mechanics Characterization of Composite/Metal Interfaces of Bonded Joints
Authors: Kim Won Seok , Lee Jung Ju
Published: March 2009

Adhesive bonding between different materials has been widely used for a large variety of
applications, such as in the aircraft, automotive, and many other civil engineering structures.
Adhesive-bonded joints as load bearing components have the potential to save significant weight and
cost over conventional riveted or bolted joints. For the last ten years a major problem in adhesive
technology has been the difficulty in predicting the accurate load bearing capacity of a joint. This
difficulty comes from the fact that the stress distribution in the adhesive joint is very complex and
singular stress field exists at the bi-material corner. And for bonded joints, the failure usually occurs at
the adhesive/adherend interface. Therefore another difficulty comes from the complex interfacial
failure analysis due to the formation of chemical bonds, whose strengths are difficult to measure.
Many studies have been conducted to investigate the effects of bond thickness, material properties of
adhesives and adherends, and geometric shape of bi-material corner tip to the fracture behavior of
bonded joints. In this paper, we analyze the stress fields at the interface corner of
composite/steel(anisotropic/isotropic) double lap joint to predict failure by using stress intensity
based fracture criterion. And analytical results are compared with experimental results of co-cured lap
joints under tensile load condition. Micro-structural features, hardness characteristics, and fracture
toughness determinations of the interfaces are also conducted.
Relation between Degree of Conversion and Post-Cured Properties of Light Cured Composite Systems Used as Filling Materials
Authors: Sunsaneeyametha Weeraw , Jaroenworaluck Angkhana , Kosachan Nudthakarn , Stevens Ron
Published: March 2009

The composite, based on a polymer matrix such as Bisphenol A glycol dimethacrylate
(Bis-GMA), urethane dimethacrylate (UDMA), and triethyleneglycoldimethacrylate (TEGDMA) and
a reinforced-ceramic filler has been used in dental restorative materials. The light curing composite
consists of Bis-GMA, TEGDMA, UDMA, Bis-GMA/TEGDMA, Bis-GMA/UDMA, or
UDMA/TEGDMA polymer systems and a fumed silica filler with 35 weight ratio loading was
synthesized using camphorquinone (CQ) and 2-(dimet6hyloamino)ethyl methacrylate (DMAEMA)
as an initiator system. FTIR spectroscopy was used to determine the degree of conversion (DC) of the
composites. Polymerization shrinkage and physical properties such as hardness strength and flexural
strength were correlated with the composites containing different polymer systems.
3D Riveting Process Simulation of Laminated Composites
Authors: Kim Seung Jo , Paik Seung Hoon , Ji Kuk Hyun , Yoon Tae Ho
Published: March 2009

Laminated composite plates have lower interlaminar strength making it difficult to apply
interference-fit rivet joining. In this paper, a three-dimensional finite element model has been
developed in order to simulate the riveting process on composite plates. The finite element model is
based on continuum elements and accounts for some important mechanisms involved in a whole
riveting process. The stresses around the rivet hole and the deformed shapes of the rivet are presented
together with the effects of the interference fit and the geometry of the washer when the rivet joints are
subjected to the compressive load. The numerical results show the applicability of an interference-fit
riveting in composite laminates.
Damage Assessment of Multi-Layered Composite Structure Using an Embedded Active Sensor Network
Authors: Su Zhong Qing , Wang Xiao Ming , Chen Zhi Ping , Ye Lin
Published: March 2009

Targeted at improving the overall integrity of functionalised composite structure, an
embedded sensor network technique was developed using circuited piezoelectric wafers. The
technical difficulties due to sensor embedment, such as electrical insulation, were addressed. With
Hilbert transform-based signal processing and a correlation-based identification algorithm, Lamb
wave signals, excited and captured by the integrated sensor network, were evaluated for damage
assessment. Effectiveness of the sensor network and proposed identification algorithm was
demonstrated by identifying delamination in orthotropic woven fabric CF/EP composite laminates.
Excellent identification capacity of the built-in sensor network indicates its considerable application
potential in providing high-fidelity data acquisition/condition monitoring for composite structures.
A New Concept for Structural Health Monitoring of Bolted Composite Joints
Authors: Xiao Yi , Kakuta Yoshiaki , Ishikawa Takashi
Published: March 2009

This study provides a practical method regarding the development of a complete
self-diagnostic technique for monitoring the bearing damage of bolted composite or metallic joints.
The basic concept is based on making BG (Bolt Gauge) measurements that has been proposed in
earlier work [1,2]. That is, bonding a strain gauge onto the surface of bolt head to monitor the bolt
strain changes that would identify bearing damage. Extensive tests using double lap bolted joint
specimens are performed to verify the health monitoring technique, including the effects of the bolt
clamp-up, material response, joint geometry and loading history. The results have shown that the
bearing damage detected by BG measurements agreed well with acoustic emission (AE)
measurements. Finite element analysis is performed to discuss the monitoring mechanisms.
Nonlinear Aeroelastic Characteristics of a Laminated Composite Wing Considering Compressible Shock Wave Effects
Authors: Kim Dong Hyun , Kim Hyun Jung , Oh Il Kwon , Lee Seok Soon
Published: March 2009

In this study, advanced computational analysis system for nonlinear static aeroelastic
problems has been successfully developed by the composite structure (FEM)-fluid (CFD) combined
method with internal iteration steps. Major focus of the present study is to investigate the static
aeroelastic characteristics of laminated composite wings including the strong normal shock waves in
the transonic and low-supersonic flow regions. The results importantly indicate that the effect of
airfoil camber on the load distribution of laminated composite wing models can be nonlinear due to
the variation of ply orientations.
Microstructure Model for Finite Element Analysis of 4-Step 3-D Rectangular Braided Composites under Ballistic Impact
Authors: Lian Jun , Gu Bo Hong , Gao Wei Dong
Published: March 2009

This paper presents a real microstructure model which has the same fiber volume fraction and
tows’ spatial configuration with 3D rectangular composites to simulate the ballistic impact damage of
the composites struck by steel projectile. The commercial available FEM code of Ls-Dyna was
employed to calculate the interaction between the composite targets and steel projectile. From the
comparison of residual velocities between simulation and experiment, it is proven the microstructure
model can simulate the ballistic penetration with higher precision than the continuum model. The
acceleration vs. time curve reveals the complicated interaction between composite and projectile in
ballistic penetration. The prominent advantage of the microstructure model is that it can simulate the
local damage mode of the composites at real microstructure level and obtain vivid simulating results.
Effect of Cure Cycle Heat Transfer Rates on the Physical Properties of an Epoxy Matrix Composite
Authors: Davies Leon W. , Day Richard J. , Bond David , Nesbitt Alan , Ellis John , Gardon Emilie
Published: March 2009

Although the autoclave technique produces composite parts of high quality, the process is
time consuming and has intrinsically high capital and operating costs. QuickstepTM is a novel
polymer composite manufacturing technique designed for the out-of-autoclave processing of highquality,
low-cost components with a reduction in cure-cycle times. This paper assesses the use of
the Quickstep method for the processing of an epoxy-carbon fibre aerospace composite material.
The Quickstep process is compared both to a thermal vacuum-bag only process and the
manufacturer’s specifications for autoclave cured panels. Higher process ramp rates, achievable by
using Quickstep, have been shown to reduce resin viscosity and facilitate void removal. Through
manipulation of the Quickstep cure cycle while the resin is at low viscosity, significant effects on
the mechanical properties of the product are demonstrated. Using Quickstep curing it has been
found that better interlaminar properties than the manufacturers autoclave data could be obtained
while the flexural strength was a little lower. The work identifies key parameters associated with the
Quickstep process giving an insight into how it can be optimised further in an attempt to produce
panel properties that rival those produced by autoclave methods.
Synergistic Toughening Effects of Nano-CaCO3 and POE on Ternary-Phase Polypropylene Nanocomposites
Authors: Rong Min Zhi , Zhang Ming Qiu , Ma Chuan Guo
Published: March 2009

Microstructure and mechanical properties of ternary PP/POE/nano-CaCO3 composites
were investigated. Two different phase structures were obtained mainly by adjusting processing
sequence. The one-step process led to the isolated distribution of elastomer and CaCO3 particles in PP
matrix, while the two-step one attained an encapsulated microstructure. In comparison with binary
blends of PP/POE or pure PP, toughness of the ternary composites was significantly increased.
Meanwhile, their stiffness and tensile strength kept nearly unchanged or slightly enhanced, implying
that there is a synergistic effect between nano-CaCO3 and POE components.
Conductive Polymer Composites Serving as Gas Sensors
Authors: Zhang Ming Qiu , Rong Min Zhi , Chen Shi Guo
Published: March 2009

The present work synthesized conductive composites consisting of waterborne
polyurethane (WPU) and carbon black (CB). Besides the low percolation threshold (0.70.95wt%),
the composites are quite sensitive to organic solvent vapors regardless of their polarities as
characterized by the drastic changes in conductivity. In the case of polar solvents, negative and
positive vapor coefficient phenomena of the composites were successively observed with a rise in CB
content. It was found that different mechanisms are responsible for the broad applicability of the
composites as candidates for gas sensing materials owing to the different interactions among the
matrix polymer, the filler particles and the solvent molecules.
Assessing the Effectiveness of Steel-Composite Hybrid Pipeline for Corrosive, High Pressure Applications
Authors: Leong Kok Hoong , Johar R.M. , Yeo A. , Nor M. Nazir M. , Jalil M.N.A. , Khalid A.N.
Published: March 2009

This paper describes an on-going study to investigate the efficacy of a steel-composite
hybrid pipe material for applications in highly corrosive and extreme pressure conditions. The study,
covering aspects of costs, design and qualification testing, has been carried out using an actual 10-in
condensate steel pipeline as the basis for comparison. On the whole it has been concluded that the
hybrid pipe material has the potential to substitute metal pipelines where corrosion resistance and
high pressure are major drivers, although assessment is continuing.
Effect of Water Absorption on the Mechanical and Dielectric Properties of Nano-Alumina Filled Epoxy Nanocomposites
Authors: Zhao Hong Xia , Li Robert Kwok Yiu
Published: March 2009

Results on the effect of water absorption on the mechanical and dielectric properties of
nano-size spherical alumina (Al2O3) filled epoxy are presented in this paper. The results from tensile
tests indicate that incorporation of the Al2O3 nanoparticles into the epoxy can improve the stiffness of
the matrix. DMA results show that the stiffness improvement is more pronounced at the rubbery
region of the matrix. The alumina nanoparticles can increase the dielectric constant of the epoxy resin
due to the increase in the total interfacial area. Upon water absorption, the mechanical properties of
the alumina/epoxy nanocomposites decrease evidently, because of the damages induced by water on
the epoxy resin. However, the ductility of epoxy can be improved by the water absorption process. In
addition, the dielectric constant of the alumina/epoxy nanocomposites increased greatly after water
absorption treatment.
High-Velocity Impact of Carbon/Epoxy Composite Laminates
Authors: Zhao Gui Ping , Wang Zheng Hao , Zhang Jian Xin , Cho Chong Du
Published: March 2009

The response of Carbon/epoxy composites under high velocity impact was investigated
experimentally. The strain rate dependent behavior of T300 Carbon/epoxy matrix composite in
tension is studied experimentally by split Hopkinson bar technique. Dynamic stress-strain plot was
obtained and compared with the quasi-static tensile test results. The results of the study indicate that
Carbon/epoxy composites are strain rate dependent materials. Stacking sequence has a significant
effect on the material response. Tensile strength of the composites all increased with increasing
strain rate. And failure strain decreased when strain rate increased.
Dynamic Torsional Buckling of an Embedded Double-Walled Carbon Nanotube
Authors: Sun C. , Lu Guo Xing , Liu K.
Published: March 2009

An elastic double-shell model based on continuum mechanics is presented to study the
dynamic torsional buckling of an embedded double-walled carbon nanotube (EDWCNT). Based on
the model, a condition is derived to predict the buckling load of the EDWCNT. It is shown that the
buckling load of the EDWCNT for dynamic torsional buckling is no less than that for the static
torsional buckling. Further, the effect of the van der Waals forces is discussed when an inner
nanotube is inserted into an embedded outer one. In particular, the paper shows that, in the absence
of the initial van der Waals forces, the buckling load of an EDWCNT is always in-between that of
an isolated inner tube and of an embedded outer nanotube, which is different from the result
obtained by neglecting the difference of radii. This indicates that disregarding the difference of the
radii of the double-walled nanotubes can not properly describe the effect of the van der Waals
forces between interlayer spacing.
Synthesis and Growth Mechanisms of Ag Metallo-Organic Nanoparticles in Different Morphologies by Using Polymer-Mediated Polyol Process
Authors: Shi Yun Ze , Fan Hui Qing , Bi Mei Tian , Zhang Jie , Zeng Xian Hua
Published: March 2009

Mono-dispersed silver nanoparticles with various morphologies were synthesized in large
quantities by reducing silver nitrate with ethylene glycol in the presence of poly(vinylpyrrolidone)
(PVP). The effects of the concentration of AgNO3, temperature, adding rates of PVP and AgNO3
injected into ethylene glycol as well as molar ratio between the repeating unit of PVP and AgNO3
were discussed. By varying the temperature and reaction time, silver nanocubes, nnoprisms and
nanospheres were obtained. It is indicated that at elevated temperatures, the ethylene glycol can
reduce Ag+ ion into Ag atoms, and thereby inducing the nucleation and growth of silver
nanostructures in the solution phase. In the polymer-mediated polyol process, PVP plays a critical
role in producing silver nanostructures with good stability and size/shape uniformity. As a result,
both the crystallinity of a seed and extent of PVP coverage on the seed were instrumental in
controlling the morphology of Ag nanoparticles.
Analysis for Vibration of Laminated Shallow Shells with Non-Uniform Curvature
Authors: Narita Daisuke , Narita Yoshihiro
Published: March 2009

Despite a large number of technical papers on vibration of composite shallow shells, all
the previous papers have dealt with shallow shells with uniform curvature to avoid difficulty in the
analysis. Recent composite products, however, require various surface designs of thin panels from the
viewpoint of industrial design, for example, in the fender and door panel designs of commercial
vehicles. The present study proposes an analytical method to deal with vibration of shallow shells
with non-uniform curvature. An interpolating function is introduced to represent the required surface
shape and the corresponding curvature is derived as a function of the position (x,y). The obtained
curvature is substituted into the total potential energy of the shell, and the procedure is shown to
derive a frequency equation in the Ritz method. Numerical examples clarifies the effects of non-
uniform curvature on the natural frequencies and mode shapes.
Preparation and Characterization of Poly(ε-Caprolactone)-Grafted-Multiwalled Carbon Nanotubes
Authors: Kim Hun Sik , Chae Yun Seok , Jin Hyoung Joon , Yoon Jin San
Published: March 2009

Sheets of poly(ε-caprolactone) (PCL)/carbon nanotube composites were prepared through
the solvent cast method. Multiwalled carbon nanotubes (MWCNT) functionalized with hydroxyl
groups were used as an initiator for the ring opening polymerization of ε-caprolactone to introduce
PCL chains to the surface of MWCNT in order to ameliorate the dispersion of MWCNT in PCL
matrix. Grafting of PCL chains to MWCNT was followed by FTIR and TEM observations. Effect of
the incorporation of MWCNT on the mechanical properties of PCL was explored before and after the
modification of the MWCNT by the PCL grafting.
Nano-Structured TiN/TiBN Multilayer Thin Films
Authors: Chu K. , Shen Yao Gen
Published: March 2009

Nano-structured TiN/TiBN multilayer thin films were deposited onto unheated Si(100)
substrates by reactive unbalanced dc-magnetron sputtering in an Ar-N2 gas mixture at a pulsed-bias
voltage of –60 V. The effects of the bilayer thickness (Λ = 1.8-7.7 nm) on microstructures and
mechanical properties have been analyzed using X-ray diffraction (XRD), high-resolution
transmission electron microscopy (HRTEM), and microindentation measurements. Microstructure
studies revealed that the TiN layers were fcc B1-NaCl structure comprising of (111)- and
(200)-oriented grains depending on Λ, while the TiBN layers were amorphous. Significant
relationships were found between hardness (H) and Λ. A maximum hardness of ~30 GPa was
observed in a multilayer film with = 1.8 nm. The possible hardness enhancement mechanism
was also discussed.
Oxygen Separator Based on SrCo0.8Fe0.1Sn0.1O3-δ Permeable Membranes
Authors: Fan Chuan Gang , Zuo Yan Bo , Lu Jun Qing , Zhu Si Wei , Liu Wei , Chen Chu Sheng
Published: March 2009

In this article, the densely SrCo0.8Fe0.1Sn0.1O3-δ (SSCF) tubular membranes were prepared
by the traditional extrusion method. The prototype oxygen separator was constructed by the
resulting SSCF tubular membrane. The resulting oxygen product had purity over 99%. At 920oC, a
tubular membrane with a wall thickness of 1.4mm, had the permeation rate of 2.4ml/min.cm2,
which kept unchanged during 1000hrs operation.