bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of Friction Force, Wear Volume and Scuffing Life of Piston Rings and Cylinder Blocks with Different Surface Roughness for Low Friction Diesel Engine
Authors: Ahn Tae Shik , Cho Dae Hyun , Lee Young Ze
Published: March 2009

Wear and scuffing tests were conducted using friction and wear measurement of piston
rings and cylinder blocks for the low friction diesel engine. Scuffing, described as sudden
catastrophic failure of lubricated sliding surfaces, usually characterized by a sudden rapid increase
in friction, temperature and noise, is an important failure mode on sliding surfaces. In this study, the
frictional forces, wear amounts and cycles to scuffing in boundary lubricated sliding condition were
measured using the reciprocating wear tester. The cylinder blocks with several values of surface
roughness were used as reciprocating specimens, and a piece of piston ring was used as fixed pin.
As increasing load by several steps in lubricated sliding, the friction signals indicated the state of
surface interactions, such as friction forces, changes of lubricating films and scuffing. There were
some rapid increases in friction forces just before the scuffing would occur. It was found that there
was the optimum value of initial surface roughness to prolong the wear life of sliding surfaces. As
decreasing the surface roughness of cylinder blocks, the wear amounts were decreased due to
increasing the contact area. There was also the optimum surface roughness to reduce the friction
and to prolong the scuffing life.
Behavior of Indented Sandwiches Structure with Nomex Honeycomb Core and Metallic Skins Subjected to Compressive Loading (CAI)
Authors: Aminanda Y. , Castanie B. , Barrau J.J.
Published: March 2009

A finite element model is proposed to determine the residual strength and the evolution
of damage area of indented sandwiches structures with Nomex honeycomb core and metallic skins
indented by a spherical indenter under longitudinal compression load (CAI). The honeycomb is
represented by a grid of non-linear springs which its behavior law is obtained by performing simple
transverse uniform compression test on a block of honeycomb alone.The comparisons between
computation and test result show that the model can simulate accurately the form of damage
geometry during indentation, its residual print when the load is relieved (relaxation) and the residual
strength and the evolution of damage geometry during CAI.
Abrasivity of a Dentifrice containing Nano Carbonate Apatite
Authors: Jang S.O. , Lee S.Y. , Kim K.N. , Kim K.M. , Kim B.I.
Published: March 2009

Carbonate apatite has a similar structure to the inorganic component of teeth and bone.
Although carbonate apatite is widely used as a bone substitute, there are no reports on its use as a
desensitizing dentifrice. This in vitro study evaluated the relative abrasivity of the dentifrice
containing nano-sized carbonated apatite (n-CAPs) using a Surface Profile Method (SPM). The
dentin specimens were made from the root of extracted human molars. The cervical part of the teeth
was sectioned with a diamond wheel disk. The teeth were embedded into an epoxy resin mold and the
surface was gradually polished using silicone carbide paper. After grinding, the degree of surface
roughness was examined within the range of 2 mm with tapping. The British Standard Institution
reference dentifrice (BSI: CaCO3 40%) and the experimental dentifrices (group 1: n-CAPs 30%,
group 2: n-CAPs 15% and silica 15%, group 3: n-CAPs 5% and silica 25%, group 4: silica 30%, group
5: CaCO3 10% and SrCl2 10%) were compared. The dentifrice slurries were prepared by mixing 24
grams of the dentifrice in 12 ml distilled water. Each tooth specimen was brushed 1,000 times with
the dentifrice slurries using a back-and-forth stroke. The relative abrasivity of each dentifrice was
evaluated by determining the ratio of the BSI standard dentifrice to each experiment. The results were
analyzed using one-way ANOVA and Tukey’s multiple comparisons using Window SPSS (Statistical
analysis system) 12.0. According to the results, Group 1 (3.2), which contained only n-CAPs
appeared to have the lowest abrasivity than the BSI dentifrice (100). However, Groups 2 (124.2), 3
(137.9) and 4 (178.1), which contained n-CAPs and silica, appeared to have a higher abrasivity than
the BSI dentifrice (p>0.05). The relative abrasivity of group 5 (38), which was a commercial
desensitizing dentifrice, was relatively lower. It appears that the higher abrasivity of the experimental
is due to the shape and size of the silica component. Therefore, n-CAPs itself has no influence on the
abrasivity of the dentifrice. The main reason for the low abrasivity of n-CAPs is believed to be its
small particle size (range 50-90nm).
Evolution of Crystallographic Texture and Mechanical Properties during Annealing of Nanocrystalline Fe-50%Ni Alloy Foil
Authors: Kim Jong Kweon , Choi Shi Hoon , Park Yong Bum
Published: March 2009

The crystallographic texture and mechanical properties were investigated in a
nanocrystalline Fe-50%Ni alloy fabricated by using an electrodeposition method. The as-deposited
texture was characterized by strong <100>//ND and weak <111>//ND fibre components, and the
occurrence of grain growth resulted in the strong development of the <111>//ND fibre components
with the minor <100>//ND fibre components. The elastic modulus and hardness were measured by
means of a nanoindentation test. The annealing led the specimen to an increase in the elastic modulus
and a strong decrease in the hardness. The elastic modului measured were compared with the
theoretic predictions based on an elastic self-consistent (ESC) polycrystal model. The theoretical
values of the elastic moduli through the thickness direction in the sample were in a good agreement
with the experimental results.
A study on MicroCantilever Deflection for the Infrared Image Sensor using Bimetal Structure
Authors: Kim Hyun Su , Park Young Chul , Oh Seung Hwan , Kim Se Hun , Jo Young Jik , Kang Jung Ho
Published: March 2009

This is a widespread requirement for low cost lightweight thermal imaging sensors for
both military and civilian applications. The feasibility of micromechanical optical and infrared (IR)
detection using microcantilevers is demonstrated. Microcantilevers provide a simple Structurefor
developing single- and multi-element sensors for visible and infrared radiation that are smaller,
more sensitive and lower in cost than quantum or thermal detectors. Microcantilevers coated with a
heat absorbing layer undergo bending due to the differential stress originating from the bimetallic
effect. This paper reports a micromachined silicon uncooled thermal imager intended for
applications in automated process control.
Residual Stress Analysis of Epoxy Coating/Substrate System Using Curvature Measurement Method
Authors: Lee Sang Soon , Jeon In Wook , Chang Young Chol
Published: March 2009

The residual stresses in an epoxy film coated on Si wafer induced during polymerization at
room temperature are investigated. The curvature measurement method and the boundary element
method (BEM) are employed to investigate the residual stresses. An epoxy film is coated on a
relatively thick Si wafer. The normal stress across thickness of the epoxy film is estimated from wafer
curvature measurements to be 15- 20MPa . The boundary element method is employed to investigate
the whole stresses in the film. The numerical result for the normal stress across thickness of the film,
σ xx , shows good agreement with the experimental result obtained by using the curvature
measurement method. The singular stress is observed near the interface corner. Such residual stresses
are large enough to initiate interface delamination to relieve the residual stresses.
Interfacial Fracture Toughness for Film on Substrate Determined by Indentation Method
Authors: Lee Soo Hyun , Kim Jink Wang , Kim Su Nam , Cho Sang Bong , Yun Jon Do
Published: March 2009

Indentation method was used to determine the interfacial fracture toughness of epoxy
coating on aluminum substrate. Tensile testing followed by finite element analysis was also
performed to determine the interface fracture toughness. Fracture toughness values determined by
two methods were consistent, giving reliability to indentation method for interfacial fracture
toughness measurement.
A Phenomenological Constitutive Model of Ferroelectrics with Gradual Domain Switching
Authors: Yu L. , Yu Shou Wen , Feng Xi Qiao
Published: March 2009

In this paper, a phenomenological, nonlinear constitutive relation of ferroelectric ceramics
is established by considering the fact that domain switching happens gradually with the external
loading. A simplified gradual switching model is suggested and implemented into the constitutive law
of ferroelectric materials. The volume fraction of domain switching is used as the internal variable in
the model, and its evolution equation with mechanical/electrical loading is given. Comparison with
experimental results shows that this simple constitutive model can predict the nonlinear hysteresis
responses of ferroelectric materials.
Effects of Microstructures on the Mechanical Properties of Dilute Al-Si Alloys
Authors: Nakagawa Keiyu , Kanadani Teruto
Published: March 2009

In this paper, we investigated effects of aging at 473K on the relationship between
microstructure in the vicinity of the grain boundaries and fatigue strength for Al-1.2%Si alloy.
Results obtained show the following features. (1) As aging time, tA increase, the tensile strength (σB)
and 0.2% proof stress (σ0.2) increase slowly, but gradually decrease after reaching a maximum at
around 18 ks. On the other hand, fracture elongation shows an opposite trend, suggesting that at aging
times above 18ks, over aging occurs. (2) The fatigue strength lowers with increasing aging time,
however, when the aging time is more than 18 ks at 473K, the fatigue strength remains almost the
same. (3) When the aging time is more than 6 ks, grain boundary precipitates with a size greater than
several 10s of nm are observed. (4) When the aging time is 18 ks, an accumulation of dislocations are
observed at the grain boundaries and in the vicinity of grain boundary precipitates, and dislocations
increase with the number of stress cycles. (5) When the aging time is more than 6 ks, the fatigue
fracture surface is mainly intergranular. These results suggest that reduction of fatigue strength
results from propagation of micro-cracks which are initiated at the large precipitates on the grain
boundaries.
Mechanical Characterisation of Thermal Barrier Coatings Using a Micro-Indentation Instrumented Technique
Authors: Kanoute Pascale , Leroy Francois Henri , Passily Bruno
Published: March 2009

An original instrumented microindenter capable of testing materials up to 1000°C in an
inert atmosphere has been developed. The method of neural networks is used to solve the inverse
problem, in order to determine the constitutive equation of the materials tested. To obtain a data
basis for the training and validation of the neural network, finite element simulations were carried
out for various sets of material parameters. To reduce the number of simulations a representative
sampling of the loading-strain responses is performed using an unsupervised network, so-called
self-organizing map.
Numerical Simulation of Ductile Fracture Process Including Shear-Lip Fracture
Authors: Kikuchi Masanori
Published: March 2009

Thickness effect is studied experimentally. At free surface of the specimen, shear lip
fracture pattern appears, though dimple fracture pattern is observed inside of the specimen. The area
of shear-lip fracture changes due to the change of the specimen thickness. In this study, experimental
study is conducted by changing specimen thicknesses. Fracture surfaces are precisely observed using
SEM, and dimple patterns on them are observed. At the free surface, very narrow no-void area is
observed. It is also found that many voids are nucleated in shear-lip fracture area. FEM simulation is
carried out using Gurson’s constitutive equation. It is found that shear-lip type fracture is simulated
near free surface area by this method. The results show similar tendency with the experimental
observation.
Analysis of Forming Process of Automotive Aluminum Alloys Considering Formability and Springback
Authors: Lee Won Oh , Kim Dae Yong , Kim June Hyung , Chung Kwan Soo , Hong Seung Hyun
Published: March 2009

Formability and springback of the automotive aluminum alloy sheet, 6K21-T4, in the sheet
forming process were numerically investigated utilizing the combined isotropic-kinematic hardening
law based on the modified Chaboche model. To account for the anisotropic plastic behavior, the
non-quadratic anisotropic yield stress potential, Yld2004-18p was considered. In order to characterize
the mechanical properties, uni-axial tension tests were performed for the anisotropic yielding and
hardening behavior, while uni-axial tension/compression tests were performed for the Bauschinger
and transient behavior. The Erichsen test was carried out to partially obtain forming limit strains and
FLD was also calculated based on the M-K theory to complete the FLD. The failure location during
simulation was determined by comparing strains with FLD strains. For verification purposes, the
automotive hood outer panel was stamped in real. After forming, the amount of draw-in, thinning and
springback were measured and compared with numerical simulation results.
The Effect of Interactive Pedometer with New Algorithm on 10,000 Step Goal Attainments
Authors: Lee Jin Oh , Kang Min Soo , Shin Jeong Hun , Lee Kil Sung
Published: March 2009

The pedometer, an objective assessment of measuring step counts, has often been used to
motivate individuals to increase their ambulatory physical activity. Minimal contact pedometer-based
intervention (MCPBI) is gaining in popularity because they are simple and inexpensive. MCPBI is
based on self-monitoring by the participants; however, one limitation of using the self-monitoring
approach was the participant attrition (i.e., dropout), which makes it difficult to achieve the successful
intervention. A new algorithm for pedometer-based intervention, the systematic-monitoring based on
conditional feedback, was designed to increase awareness and allow participants to more successfully
attain their step goals. Thus, the purpose of this study was to examine the effect of the
systematic-monitoring based on conditional feedback algorithm on 10,000 step goal attainments. The
study result can be used to design more comprehensive pedometer-based physical activity
interventions to increase individuals’ overall health status.
Uniaxial Cyclic Deformation Behavior of 6061Al Alloy and its Time-Dependence at Room and High Temperatures
Authors: Kang Guo Zheng , Liu Yu Jie , Ding Jun
Published: March 2009

The cyclic deformation behavior of 6061Al-T6 alloy was studied by uniaxial cyclic
straining or stressing tests at room and high temperatures. The cyclic softening/hardening feature of
the material and its effect on the uniaxial ratcheting occurred under asymmetrical cyclic stressing
were discussed. The cyclic deformation behaviors of the material presented at various loading rates
and with certain peak and/or valley strain or stress holds were addressed. It is concluded from the
experimental results that 6061Al-T6 alloy presents slightly cyclic softening feature, and its cyclic
deformation is time-dependent even at room temperature. The ratcheting strain produced at lower
stressing rate and with longer hold-time is apparently larger than that at higher stressing rate and with
fewer hold-time. Some significant conclusions useful to construct the constitutive model to describe
such cyclic deformation behaviors are obtained.
Optimization of a Gate Valve Using Orthogonal Array and Kriging Model
Authors: Oh Seung Hwan , Kang Jung Ho , Joo Won Sik , Song Xue Guan , Kong Hyeung Geol , Park Young Chul
Published: March 2009

The optimization of gate valve was performed using Kriging based approximation model.
The DACE modeling, known as the one of Kriging interpolation, is introduced to obtain the
surrogate approximation model of the function. In addition, we describe the definition, the
prediction function and the algorithm of Kriging method and examine the accuracy of Kriging by
using validation method.
Multiscale Modelling of Nanoindentation
Authors: Chang Hyung Jun , Han Heung Nam , Fivel Marc
Published: March 2009

Nanoindentation is an interesting technique used to probe the local mechanical properties
of a material. Although this test has been widely used and developed over the world during the past
few years, it remains a lot of uncertainties regarding the interpretation of nanoindentation data. In
this study, we propose to simulate the nanoindentation test of FCC single crystals like Cu or Ni
using three numerical models. At the lowest scale, molecular dynamics simulations give details of
the nucleation of the first dislocations induced by the indentation. At an intermediate scale, discrete
dislocation dynamics simulations are performed to study the evolution of the dislocation
microstructure during the loading. Finally, at the upper scale, 3D finite element modelling using
crystal plasticity constitutive equations give a continuum description of the indentation induced
plasticity. It is shown how the different models are interconnected together.
Molecular Dynamics Study on Characteristics of Misfit Dislocations in Ni-Based Superalloys
Authors: Yashiro Kisaragi , Suzuki Yuuhu , Pangestu Joy Rizki , Tomita Yoshihiro
Published: March 2009

By using molecular dynamics simulation, misfit dislocation networks are made on
semi-coherent interfaces in a laminate structure of Ni and Ni3Al single crystals. The core structure of
the networks is discussed in detail, focusing on the different atomic configuration at the interfaces; e.g.
with or without Al atoms on the Ni3Al side. It is revealed that the networks can be a source of partial
dislocation loops under the external loading; however, the loops tend to form immobile wedge-like
stacking faults, analogous to the stacking fault tetrahedron (SFT), near the interface with Al atoms. On
the other hand, the loops propagate into both Ni and Ni3Al phases, from the network dislocations on
the interface without Al atoms.
On the Material Process Simulation Code COSMAP- Simulated Examples and its Experimental Verification for Heat Treatment Process
Authors: Ju Dong Ying , Inoue Tatsuo
Published: March 2009

Strategy and function of a new developed FEM code COSMAP(COmputer Simulation of
MAterial Process) for surface hardening during of thermo-mechanical processing, including heat
treatment, carbonizing and nitriding, is briefly introduced in this paper. The simulation code is
developed based on the metallo-thermo-mechanical theory considering the coupled equations of
diffusion, heat conduction, inelastic stresses and kinetics of phase transformation. Some examples
of simulation and the experimental verification for carbonized quenching, carbonizednitrided-
quenching process of a cylinder and ring as well as a gear are illustrated, and comparison
of the simulated values of distortion, residual stresses and profile of induced phases with the
experimental data is made with some discussions.
Environment Induced Cracking of Turbine Disc Steel: Effect of Organic Acids on Corrosion Fatigue of 3.5NiCrMoV Steels in High Temperature Water
Authors: Maeng W.Y.
Published: March 2009

Organic acids (acetic and formic acid) are produced by the decomposition of ETA
(Ethanol Amine, C2H7NO) used as pH controller of secondary water in nuclear power plants.
Corrosion Fatigue (CF) tests (R=0.2, 0.1Hz) were conducted to evaluate the effect of acetic acid on
the CF crack growth rate in high temperature water at 150°C. Acetic acid significantly influenced
the environmental cracking behavior of turbine disc steels in high temperature water. The CF crack
growth rates of turbine disc steels increase as the organic acid concentration increase to a critical
saturation pH value (~pH 4). Beyond the saturation value of pH, the CF crack growth rates decrease
significantly. The higher CF crack growth rate of the higher pH solution in water of intermediate
content range (pH 4~pH 5) of acetic acid is due to the higher content of H+ enhancing the reduction
reactions. Crack tip blunting prevents the CF cracks from growing with increasing rate in the
solution of organic acid concentrations beyond the critical value.
Modelling of Effect of ASR on Concrete Microstructure
Authors: Çopuroğlu Oğuzhan , Schlangen Erik
Published: March 2009

In the present study the damage mechanism of Alkali-Silica-Reaction (ASR) in concrete
bearing reactive volcanic rock is investigated. A combined numerical and experimental research is
presented. The mechanism of ASR is investigated on a concrete microbar specimen by using various
microscopy techniques. A meso mechanical model based on lattice theories is used as a starting point.
Variables in the model are the properties of the concrete components on the meso-level, like
mechanical properties of cement paste, aggregates, dissolved aggregate, bond properties and finally
the properties of the gel. It is found that current numerical model is able to simulate ASR cracks
similar to the experimental observations.
Sedimentation of Barium Titanate Nanoparticles in a Suspension under Application of an Electric Field
Authors: Arimura Masashi , Makino Teruhisa , Fujiyoshi Kunitaka , Yamashita Yoko , Kuwabara Makoto
Published: March 2009

Barium titanate nanoparticle (BT-NP) suspensions were prepared by dispersing sol-gel-derived
BT-NPs in ethylene glycol monomethyl ether (EGMME) under sonication. When an electric field
was applied, a part of the BT-NPs in a suspension was deposited on the cathode by
electrophoretically deposition and most of the rest of the BT-NPs settled down towards the bottom
of a container. The concentration of BT-NPs in the lower part of the container (Cbottom) increased
with time until the Cbottom reached a specific concentration (threshold concentration) at which
sedimentation of BT-NPs start to occur. The threshold concentration of the nanoparticles
sedimentation gave a significant influence upon the aspect of a BT-NPs deposit formed on the
cathode.
Synthesis of Highly Aligned Carbon Nanotubes in Liquid Phase
Authors: Mikami Masafumi , Yamagiwa Kiyofumi , Takeuchi Tsuneharu , Saito Morihiro , Kuwano Jun
Published: March 2009

Aligned carbon nanotube arrays (CNTAs) were readily synthesized by a resistance heating method
on a substrate of commercially available stainless steel which has more plentiful availability than
the wafers of Si and quarts. The catalyst was supported on the substrate by dip coating with a
methanol solution of M(C5H5)2(M=Co,Fe), and the substrate was electrically heated at 800oC in
methanol. Highly aligned CNTAs were grown from the catalyst prepared from 0.02 M Co(C5H5)2
methanol solution. The alignment was influenced by the concentration and the kind of M(C5H5)2.
Synthesis of Complex Perovskite Oxides via Nanosheets Process
Authors: Inaba Keigo , Suzuki Shinya , Noguchi Yuji , Miyayama Masaru , Osada Minoru
Published: March 2009

Complex perovskite oxides of Sr0.5(Nb0.5Ta0.5)O3 were synthesized by reassembling (SrNb2O7)2−
and (Sr1.5Ta3O10)2− nanosheets followed by topochemical dehydration with heat treatment. Atomic
force microscopy (AFM) images showed that the thicknesses of the (SrNb2O7)2− and (Sr1.5Ta3O10)2−
nanosheets were approximately 6 nm (7 unit layers) and 4 nm (3 unit layers), respectively. Raman
scattering measurement has suggested that nanosheet-processed Sr0.5(Nb0.5Ta0.5)O3 with
B-site-cation ordering has a superlattice-like structure composed of alternating layers of Sr0.5NbO3
and Sr0.5TaO3 along the c-axis. Nanosheet-processed Sr0.5(Nb0.5Ta0.5)O3 with B-site-cation ordering
exhibited a dielectric permittivity of 42 (1 MHz), which was lower than that of solid-state-reacted
samples (65) with disordered B-site cations.
Defect Control for Superior Properties in K0.5Na0.5NbO3 Single Crystals
Authors: Kizaki Yoichi , Noguchi Yuji , Miyayama Masaru
Published: March 2009

Single crystals of K0.47Na0.53NbO3 (KNN) and Mn-substituted KNN (Mn-KNN, K0.53Na0.47Mn0.004Nb0.996Oy) were grown by a flux method, and the influence of lattice defects on the polarization and leakage current properties was investigated. As-grown KNN did not show an apparent polarization hysteresis loop due to its large leakage current (~10-3 A/cm2). The substitution of 0.4%-Mn at the Nb site and subsequent annealing under a moderate oxidative condition were effective in suppressing the leakage current of KNN crystals. 0.4%-Mn-KNN annealed at 1100°C in air exhibited a low leakage current (~10-8 A/cm2), a relatively large remanent polarization of 40 μC/cm2 and a coercive field of 12 kV/cm at 25°C. The oxidation of Mn and Nb ions during annealing in air is found to play an essential role in the low leakage current of Mn-KNN.
Preparation and Flame Ablation/Oxidation Behavior of ZrB2/SiC Ultra-High Temperature Ceramic Composites
Authors: Wang Chang An , Wang Hai Long , Huang Yong , Fang Dai Ning
Published: March 2009

ZrB2/SiC ceramic composites reinforced by nano-SiC whiskers and SiC particles have been prepared by hot-pressing at 1950°C for 1hr under 20 MPa pressure in flow argon atmosphere. Effects of SiC addition on microstructure, mechanical properties and thermal ablation/oxidation behavior of ZrB2/SiC composites were investigated. The results showed that the addition of SiC effectively improved the densification of ZrB2/SiC composites and almost full dense ZrB2/SiC composites were obtained when the amount of SiC increased up to 20 vol%. Flexural strength and fracture toughness of the ZrB2/SiC composites were also enhanced; the maximum strength and toughness reached 600 MPa and 8.81 MPa·m1/2 at SiC additions of 20 vol % and 30 vol%, respectively. The composites possessed good resistance to flame ablation and could keep the whole shape without distinct peeling or cracking after flame ablation by oxyacetylene flame for 3 mins. The more SiC added, the better resistance to flame ablation the composites displayed.
Fabrication and Formation Mechanism of In Situ AlN and Mg2Si Particles-Reinforced Mg Matrix Composites
Authors: Zhang Cong Fa , Cao Wei , Fan Tong Xiang , Zhang Di
Published: March 2009

The (AlN+Mg2Si)/Mg metal matrix composite was successfully fabricated by adding Si3N4
into Mg-Al alloy. The formation mechanisms of AlN and Mg2Si were analyzed; the effects of
synthesizing temperature and holding time were investigated as well.
Oxidation Behavior of Carbon Phase in 3D C/SiC Composites
Authors: Li Jian Zhang , Zhang Jun , Zhang Li Tong , Cheng Lai Fei , Xu Yong Dong
Published: March 2009

Carbon fiber reinforced silicon carbide matrix composites (C/SiC) are promising candidate materials for high-temperature structural applications. However, in oxidizing environments the two main constituents, that is, carbon fiber and pyrolytic carbon interphase which bears and transfers loads respectively are susceptible to deplete rapidly for oxidation. In this paper, the oxidation behavior of carbon fiber and pyrolytic carbon were investigated by simulating environmental experiments and scanning electron microscopy. The reactivity discrepancy in the carbonaceous constituents and in the different zone of carbon fiber was discerned. After oxidation, the morphology of carbon phase broken before oxidation were compared with that of those broken after oxidation. Based on the microstructural model, the contrast results of morphology were well interpreted from the reactive preference and selectivity.
Finite-Element Simulation and Analysis on High Velocity Impact Damage of Aircraft Panel Structure
Authors: Li Shu Lin , Hou Man Yi
Published: March 2009

The finite-element simulation models of the projectile and the discrete rod impacting to the
aircraft panel structure in high velocity are established according to some experiment projects. Based
on dynamic finite-element Program, the forming of impact damage in the panel structure is simulated.
Through comparing the simulation results of damage pattern and size in the panel to the experiment
results, the reliability of the material models and equations of state and contact algorithm used in the
simulations is testified. Take the simulation of projectile vertically impacting to the panel as example,
the aircraft panel structure response characteristics are analyzed briefly based on the results including
the displacement of typical node in the panel, the stress course of one element and the energy change
of the panel.
Numerical Studies of End Effect on Crack Propagation Behavior of Brittle Specimen Containing Pre-Existing Crack under Uniaxial Compression
Authors: Huang Ming Li , Wang Shan Yong , Lu Wei , Zhu Wan Cheng
Published: March 2009

In this paper, a Material Failure Process Analysis code (MFPA2D) was employed to
investigate the interaction of end effect zone of specimen with the wing crack propagation inside the
brittle specimen containing pre-existing flaws under uniaxial compression comparing with the
experimental results. The numerical results show that the shorter the distance between the
pre-existing flaw and the specimen's end , the slower the crack propagation process and the shorter
wing propagation length is , and vice versa. In addition, the end effect zone was also influenced by the
wing crack propagation.
Dynamic Fracture Behavior of Magnesium Alloy
Authors: Shimamoto Akira , Hwang Do Yeon , Kubota Ryo , Nogata Fumio
Published: March 2009

Static and dynamic loading fracture experiments were conducted on magnesium alloy
under equal and unequal biaxial stress. Cross shape specimens with a crack on their center were used
for tests. Fracture behavior was observed by two methods; the caustic and the one point gauge
method. From the observation, the stress intensity factors and the fracture toughness values were
calculated. It was found that the one point gauge method was not suitable for calculating the stress
intensity factor with a strain gauge widely available. The fracture toughness values obtained under
equal biaxial stress were 1.2~2.3 times greater than those of magnesium alloy naturally inherited.
Moreover, plate thickness was negatively related to the fracture toughness value.
Effects of Joint Width on Strength, Stress-Strain Curve and Strain Localization of Rock Mass in Uniaxial Plane Strain Compression
Authors: Wang X.B.
Published: March 2009

Effects of joint width (JW) on the macroscopic stress-strain curve, the failure process and
mode of jointed rock specimen (JRS) in plane strain compression are modeled by use of FLAC. The
failure criterion of intact rock outside the inclined joint is a composite Mohr-Coulomb criterion with
tension cut-off and the linear strain-softening post-peak constitutive relation is adopted. The joint is
treated as quadrate elements of ideal plastic material beyond the peak strength. A written FISH
function is used to automatically find elements in the joint. Numerical results show that the peak
strength of JRS depends on JW and is lower than that of intact rock specimen without joint. For JRS,
the shear strains are concentrated into the joint or the new generated shear bands (NGSBs); the peak
strength decreases with an increase of JW. At lower or higher joint inclination angle (JIA), the failure
mode and pattern of NGSBs are not related to JW. The post-peak response becomes ductile at wider
JW and higher JIA. The post-peak slope of stress-strain curve at lower JIA is not dependent on JW
since the width and inclination angle of NGSBs are not affected by JW.
Failure Process and Stress-Strain Curve of Plane Strain Rock Specimen with Initially Random Material Imperfections
Authors: Wang X.B.
Published: March 2009

The failure process of heterogeneous rock specimen with initially random material
imperfections in uniaxial plane strain compression and the macroscopically mechanical response are
numerically modeled by using FLAC (Fast Lagrangian Analysis of Continua). A FISH function is
generated to prescribe the initial imperfections within the heterogeneous specimen by using Matlab.
The imperfection is weaker than the intact rock. Beyond the failure of the imperfection, it undergoes
ideal plastic behavior, while intact rock exhibits linear strain-softening behavior and then ideal plastic
behavior once failure occurs. The specimen with smooth ends is loaded at a constant strain rate and is
divided into 3200 elements. The maximum numbers of the initial imperfections in five schemes are
100, 300, 500, 700 and 900. The effects of the number of the imperfections on the fracture process, the
final fracture pattern and the complete stress-strain curve are investigated. Prior to the peak stress,
some imperfections extend in the axial direction and then a part of them coalesce to form inclined
shear bands. Beyond the peak stress, shear bands progressively intersect the specimen; in the process
the number of the yielded elements approximately remains a constant. With an increase of the number
of the initial imperfections, the spacing of shear fractures decreases, the peak stress and corresponding
axial strain decrease; the post-peak branch of stress-strain curve becomes steeper; much more
elements fail in tension; the number of the yielded elements in tension in the vicinity of the two lateral
edges of the specimen remarkably increases.
Geometrically Nonlinear Deformation of Circular Sandwich Plates under Transversely Non-Uniform Temperature Rise
Authors: Yang Jing Ning , Zhao Yong Gang , Qiu Ping , Liu Cai Xue
Published: March 2009

Geometrically nonlinear bending and buckling of circular sandwich plates subjected to
transversely non-uniform temperature rise is investigated in this paper. On the basis of sandwich
plate theory, nonlinear equations governing the large thermal axis-symmetric deformations of
circular sandwich plate in terms of the middle plane’s displacements are derived. Numerical
solutions of the nonlinear boundary value problem are obtained by using the shooting method.
Equilibrium paths and configurations for different boundary conditions and different values of
materials and geometry parameters are illustrated. Numerical results show that the boundary
conditions and the stiffness greatly effect critical buckling loads.
The 3D-Crack Growth Mechanism of Brittle Material under 3D Compression
Authors: Lin P. , Wang R.K. , Zhou W.Y. , Yang Q.
Published: March 2009

In this paper, failure behavior of basalt specimen containing 3D-flaw with different angles
is investigated under triaxial compression. The process of crack growth was observed by
computerized comography (CT). Based on the experimental results, the following conclusions were
obtained: Under 3D loading condition, the angle of pre-existing flaw has a dominating influence on
the zone of stress concentration. When the flaw angle is parallel to the direction of vertical loading,
the failure peak strength is greater than that of sample containing other flaw angle, and the final failure
mode is irregular. When the pre-existing flaw angle is about 60 degree with horizontal loading
direction, stress concentration is easy to form at the tip of pre-existing flaw, and lead many small
radicalized cracks to propagate. Under 3D loading condition, the cracking surface generally is
distorted and lead crack to propagate in irregular direction, and then form irregular space failure with
mixed mode. The experimental results observed here has shown that the experimental system and
method in this study is efficient and robust.
High Speed Fracture Phenomena in Dyneema Composite
Authors: Heru Utomo Beate D. , van der Meer B.J. , Ernst L.J. , Rixen D.J.
Published: March 2009

Dyneema composite is used in lightweight armour applications, because of its high
specific material properties such as strength and stiffness. In armour applications, Dyneema
composite is used to protect people or vehicles from projectile impact. In order to be able to
guarantee a certain protection level, an accurate prediction of fracture phenomena that are caused by
projectile impact is required. Currently, fracture phenomena such as delamination and fibre fracture
are not accurately described. This is because a good understanding of fracture phenomena in
Dyneema composite lacks. Therefore, both Dyneema fibre and Dyneema composite are analysed by
different (impact) experiments to gain more insight in both the fracture phenomena as well as in the
material properties. Parallel to these experiments, a start is made with the development of a new
material model in ABAQUS\Explicit using cohesive zone techniques that is able to predict the
fracture phenomena due to projectile impact.
Effect of Residual Stress Field in Front of the Slant Precrack Tip on Bent Fatigue Crack Propagation
Authors: Shimizu Kenichi , Torii Tashiyuki , Nyuya J. , Ma Y.
Published: March 2009

Fatigue crack bending and propagation behaviors were studied under mixed-mode
conditions using annealed and fatigue slant precracks. The bent fatigue crack initiated from the
fatigue slant precrack propagated under mixed-mode conditions with mode II stress intensity factor
evaluated from the crack sliding displacement measured along the crack. On the other hand, bent
fatigue cracks propagated under the mode I condition for an annealed slant precrack specimen. The
forces which suppress the crack opening/sliding were calculated along the slant precrack and the bent
crack by FEM (Finite Element Method) analysis. As a result, the crack opening suppress forces were
generated by the compressive residual stress around the fatigue slant precrack, while the forces which
promote the crack sliding were caused by the residual stress field in front of the fatigue slant precrack.
A Study on the Mechanism of Small Fatigue Crack Deflection Behavior in Alpha-Brass by Means of In Situ Atomic Force Microscopy and Crystallo-Graphic Orientation Analysis
Authors: Sugeta Atsushi , Uematsu Yoshihiko , Jono M.
Published: March 2009

Successive observation of transgranular small fatigue crack growth behavior of
alpha-brass was performed by means of an atomic force microscope (AFM) equipped with
small in-plane bending fatigue testing machine. In the low growth rate region after crack
initiation, the fatigue crack grew in a zig-zag manner as a result of successive crack branching
and deflection. The fatigue crack deflection behavior was investigated by the crystallographic
orientation analysis based on the Electron Back Scatter Diffraction (EBSD) technique. The
slip factor considering the slip system and singular stress field at the crack tip was introduced
in order to evaluate the easiness of slip deformation instead of Schmid factor. The direction of
crack deflection was found to be explained well by the slip factor and the geometric relative
location between the preferential slip plane and crack front.
Study on the Fracture Energy and Fracture Toughness of the Polypropylene Fiber Reinforced Concrete
Authors: Hua Yuan , Zhou Tai Quan , Lian Jun Ying
Published: March 2009

The fracture toughness and the fracture energy are obtained on the notched beams in
three-point bending according to the RILEM draft recommendation. An experiment is designed to
obtain the law on the alteration of the PPFRC’s (Polypropylene Fiber Reinforced Concrete) fatigue
life and fatigue strength caused by the fibers. S-lgN curve is plotted according to the experimental
data and fatigue is obtained through the Linear Regression. Theoretical analysis of the PPFRC’s
bending fatigue characteristic is carried out. The fiber’s influence on the PPFRC’s fatigue behavior
is stated and the fiber reinforcement mechanism is discussed. The result shows that the fiber can
improve the PPFRC’s fatigue life and fatigue strength. The composition and development of the
fatigue strain under the cyclic load are analyzed using experimental data. The law of the fatigue
damage accumulation and evolution under cyclic load is studied. A fatigue damage mode, which
can be used to predict the fatigue life of the PPFRC, is established.
Fabrication and Properties of a Novel Anti-Radiation BaPb0.6Ce0.4O3/Al Composite
Authors: Fan Guo Hua , Geng Lin , Zheng Zhen Zhu , Cao Guo Jian , Feng Yu Jie , Liu Yan Kun
Published: March 2009

In this paper, a BaPb0.6Ce0.4O3 (BPCO)/Al matrix composite with a good anti-radiation
property was fabricated by hot pressing in air for the first time. Differential scanning calorimeter
(DSC) and Thermal Gravimetric (TG) analysis of the compacted blended powders were performed
in air to study the oxidation behavior, by which the hot-pressing parameters were determined.
Transmission electron microscope (TEM) images and X-ray diffraction pattern showed that there
was an incomplete reaction between aluminum alloy matrix and BPCO particles during fabrication
process. Compared with the aluminum alloy matrix, the X-ray and γ-ray absorption abilities of the
composite were increased by 68.05% and 46.63%, respectively.
Fatigue Properties of Ni-Base Superalloy in Long Life Region
Authors: Matsuyama Y. , Kawagoishi Norio , Wang Qing Yuan , Morino Kazuhiro , Kondo Eiji , Yan Nu
Published: March 2009

Fatigue properties of Inconel 718 at 500°C were investigated under rotating bending.
Fatigue strength was higher at 500°C than at room temperature. Fracture occurred by the initiation
and propagation of a surface crack in short life region. The early propagation of a surface crack
smaller than 20-30 μm was suppressed by oxidation at 500°C. This is a main reason for the higher
fatigue strength at 500°C. However, the crack growth after the retardation of a small crack growth
at 500°C was accelerated reflecting the lower static strength. On the other hand, in long life region,
though a surface crack initiated at the early stage of fatigue life similar to the case in short life
region, the crack did not propagate over 20-30 μm, and an internal fracture occurred. Consequently
S-N curve at 500°C showed a duplex property and the fatigue limit was not recognized. The
subsurface damage was initiated at the early stage of fatigue life.
Analytical Solutions for Residual Stresses of Functionally Graded Medium with Inhomogeneity
Authors: Ou Zhi Ying , Lei Dong Xia
Published: March 2009

The residual stresses induced in functionally graded medium (FGM) with inhomogeneity
cooling down from the processing temperature are determined with concentric cylinder model and
analytical solutions of the inhomogeneous governing equations for displacement components. The
analytical solutions derived here are general for power-law variations of the elastic moduli of the
FGM. With a power exponent, analytical expressions for the residual stresses of FGM with
inhomogeneity can be obtained. By changing the power exponent and the coefficient of the power
terms, the solutions obtained here could be applied to different properties of FGM with
inhomogeneity. The results show that the huge difference exists between FGM with inhomogeneity
and homogeneous medium with inhomogeneity. The variations of FGM and inhomogeneity size
have a great deal of effect on the residual stresses in FGM.
Influence of Nowonty Phase on the Fracture Toughness of SiC/MoSi2 Composites
Authors: Kang Peng Chao , Wu Gaohui , Yin Zhong Da
Published: March 2009

MoSi2-SiC precursor powder has been synthesized via the mechanical alloy method with
the elements Mo, Si and C powder. The SiC/MoSi2 composites with different SiC volume fraction
have been prepared by reactive hot-pressing the precursor powder at 1350 °C. There is a significant
increase in the fracture toughness due to addition of SiC reinforcement. However, the intermediary
ternary phase exists in this system—namely, Mo5Si3C, Nowotny phase, which has negative effect on
the fracture toughness, and can be eliminated through high temperature treatment at 1600 °C for 2 hrs.
Effect of Solution Treatment on Tensile Properties of AA2024 Matrix Composite Reinforced with Magnesium Borate Whisker
Authors: Wu Pei Lian , Yao Chen Yi , Wang Li Dong , Fei Wei Dong
Published: March 2009

Magnesium borate whisker reinforced aluminum alloy 2024 (AA2024) composite was
fabricated by squeeze casting method, after was CuO coating of the whisker. The interfacial
reaction in the composite was investigated. To change the interfacial reaction degree, the solution
treatment for different time was carried out. The results show that the interfacial reaction degree
increases with solution time increasing. The maximum ultimate tensile strength can be obtained
when the solution time is suitable.
Effect of ECAP on the Microstructure and Tensile Property of SiCp/AZ91 Magnesium Matrix Composite
Authors: Chang Hai , Wang Xiao Jun , Zheng Ming Yi , Wu Kun
Published: March 2009

Magnesium matrix composite reinforced with SiC particle was fabricated by
compocasting method. The SiCp/AZ91 composite was extruded initially, then subjected to ECAP.
The microstructure and tensile properties of the composite at ambient and elevated temperature
were investigated. After ECAP, the matrix alloy was significantly refined due to the dynamic
recrystallization occurred during ECAP. Both the ambient yield stress and ultimate tensile stress of
SiCp/AZ91 were increased after 1-pass and 2-pass ECAP and decreased after 4-pass ECAP. The
ECAP processed composite exhibited superplasticity at elevated temperature, which is mainly due
to the grain refinement of matrix alloy. The dominant deformation mechanism of the ECAPed
composite at high temperature was grain boundary sliding. However, the sliding was prohibited due
to the present of SiC particle.
Experimental Study on the Mechanical Properties of Metal Oxides Filled PA1010 Composites
Authors: Huang Chuan Hui , Wang Shi Bo , Liu Li Guo
Published: March 2009

This paper focuses on the effect of metal oxides on the mechanical properties of PA1010
composites, such as the tensile strength, compressive strength, shear strength and hardness. The
experimental results show that the tensile strength of PA1010 composites filled with CuO and Al2O3
particles slightly decreases with the oxide contents increasing. However, the tensile strength of
PA1010 composites filled with Fe3O4 particles increases, which has the average increment in tensile
strength of 23.7% than the pure PA1010 materials. The results indicate that the compressive
strength can be increased by adding CuO, Al2O3 and Fe3O4 particles into PA1010 polymer. The
results exhibit that Fe3O4 particles have significant effects to increase the shear strength of PA1010
composites. However, Al2O3 particles filling reduce the shear strength of the composites.
Mechanical Alloying Influence on the Sintering of Cu-Fe Compound Powders
Authors: Sun Jin Feng , Wang Ming Zhi , Li Xiao Pu , He Zhan Wen , Zhao Yu Cheng
Published: March 2009

In this paper, X-ray diffraction (XRD), differential scanning calorimetry (DSC) and
sintering process were used to characterize Cu-Fe compound powders milled for different times.
The increment of defects and the change of granularity, grain size and crystal structure were
discussed. Mechanical Alloying (MA) influence on the sintering of Cu-Fe compound powders was
analyzed. The results showed that, the refinement of the powders and the increment of defects such
as interface and dislocation induced the energy storage. The stored energy released in the sintering
process, which reduced the activation energy of vacancy and the activation energy of diffusion. So
the sintering temperature was reduced and the structure, strength and hardness of specimens were
improved.
Fabrication and Mechanical Properties of Carbon Nanotubes/Epoxy Resin Composites Prepared by a Sonication Technique
Authors: Kumfu Supreyak , Chailangka V. , Nhuapeng Wim , Singjai Pisith
Published: March 2009

Carbon nanotubes (CNTs)/epoxy resin composites were prepared by using a sonication
technique. Microstructure, mechanical and physical properties such as hardness, wear resistance,
tensile strength and density of the composite samples were examined. The tensile strength of the 0.6
vol.% CNTs/epoxy resin composites compared with the monolithic epoxy resin increased 183%.
The hardness and wear resistance were maximum at 0.8 vol.% CNTs. Moreover, SEM image of the
composites indicated that there is good adhesion between CNTs and the epoxy resin.