bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Characterization of FSW T-Joints of Light Alloys
Authors: Fratini Livan , Micari Fabrizio , Squillace Antonio , Giorleo G.
Published: March 2009

Welding is playing a growing role in transport industry due to relevant advantages it
allows. Friction Stir Welding is considered one of the most promising joining technologies,
especially when it is applied to light alloys. Focusing attention on FSW of T-joints, several
parameters have to be considered, and due to thermo-mechanical features of process, T joints need a
dedicated approach. A set of previously developed experiments has shown that the tilt angle plays a
relevant role in the joint strength. Furthermore it should be observed that T-joints are very often
utilized in aerospace industries since the produced structures are composed of joined skins and
stingers. Numerous data are reported in literature about FSW of butt joints, very few data, to
authors’ knowledge, exists on T joints. In this paper a micro structural and mechanical analysis has
been developed on FSW T-joints of AA 6082 T6 rolled plates, realized setting welding direction
both parallel and perpendicular to rolling direction. The obtained results can be considered as a
further acquired knowledge in the comprehension and the design of FSW processes.
Enhanced Numerical Results on Friction Stir Welded Aluminium Butt Joints
Authors: Staud Detlev , Giera Arthur , Merklein Marion , Geiger Manfred
Published: March 2009

Friction stir welding is a newer technology to join materials in the solid phase. Therefore
plenty of problems which appear by melting phase welding technologies for aluminium alloys are
avoided by this process. This is the main chance for friction stir welding to be accepted and
integrated in forthcoming applications, especially for uses out of aluminium alloys. Starting from
former results for friction stir welding of aluminium this article deals with the determination of the
constitutive material properties of friction stir welded aluminium tailored blanks with regard to the
finite-element (FE) simulation of sheet metal forming. The FE simulation of the formability of
welded sheet metal demands the knowledge of the precise mechanical properties of the base
material as well as the characteristic zones of the weld seam, which are affected by friction stir
welding. While ordinary tensile tests can only determine the constitutive behaviour of a simple
tensile specimen, an optical strain measurement can be used to determine flow stresses of the base
and of the welded material with an adapted tensile specimen, respectively. By the usage of the so
called rule of mixture the advantages of this new approach is demonstrated with a comparison of the
tensile forces within FE simulations and experimental validations. For this purpose specimen with
the weld seam oriented perpendicular and parallel to the uniaxial loading direction are utilized.
Computer Assisted Design of Actuator Systems for Laser Micro Adjustment
Authors: Plettke Raoul , Hagenah Hinnerk , Geiger Manfred
Published: March 2009

The adjustment of micro system components with laser forming using especially designed
sheet metal actuator systems is a new and promising technology. However, due to the complexity
of the design challenge and the contradicting targets that have to be considered computer
assistance for the design of the actuator systems is needed.
In order to build such a system several steps have to be taken. First, the actuators have to be modeled
with all necessary data. Second, quality criteria have to be defined and fully automated assessment
modules for every single objective have to be implemented. And third, an optimization system
which utilizes the assessment modules must be developed to improve an initial design. This paper
presents a solution for each of these steps. It closes with first results of a reduced version of the system
as well as an outlook on the next development steps.
Numerical Simulation of Sheet Metal Forming Processes Using a New Yield Criterion
Authors: Comsa Dan Sorin , Banabic Dorel
Published: March 2009

The paper is focused on the development of a new phenomenological yield criterion able
to describe the inelastic response of sheet metals subjected to cold forming. The model consists in
two components: the equivalent stress and the hardening law. The equivalent stress is a function
incorporating 8 material parameters. Due to these parameters, the new formulation is able to
describe four normalized yield stresses (y0, y45, y90, yb) and four coefficients of plastic anisotropy
(r0, r45, r90, rb). The hardening law is defined as a linearly asymptotic function containing 4 material
parameters. The numerical tests presented in the last section of the paper prove the capability of the
elastoplastic constitutive models based on the new yield criterion to model the earing as well as the
wrinkling phenomena accompanying the deep-drawing process.
An Intelligent Tool to Predict Fracture in Sheet Metal Forming Operations
Authors: Di Lorenzo Rosanna , Ingarao Giuseppe , Micari Fabrizio
Published: March 2009

One of the main issues in sheet metal forming operations design is the determination of
formability limits in order to prevent necking and fracture. In fact, the ability to predict fracture
represents a powerful tool to improve the production quality in mechanical industry. Many
researchers investigated the problem here addressed, mainly studying forming limit diagrams (FLD)
or developing fracture criteria which are able to foresee fracture defects for different processes. In
this paper, the author present some early results of a research project focused on the application of
artificial intelligence (AI) for ductile fracture prediction in sheet metal forming operations. The
main advantage of the application of AI tools and in particular, of artificial neural networks (ANN),
is the possibility to obtain a predictive tool with a wide applicability. The prediction results
obtained in this paper fully demonstrate the usefulness of the proposed approach.
Economical and Ecological Aspects of Single Point Incremental Forming Versus Deep Drawing Technology
Authors: Petek Aleš , Gantar Gašper , Pepelnjak Tomaz , Kuzman Karl
Published: March 2009

In contemporary industrial production the ecological aspects have increasingly important
role in selection of sheet metal forming process. To produce sheet metal parts with minimal
environmental burdening the shortening of forming processes including the procedures for
production of appurtenant forming tools as well as decrease use of lubricant is prerequisite. The
ecological aspects have to be considered also already in developmental phase where the forming
technology is evaluated in digital environment with FEM simulations.
In addition, particularly in small and medium batch production the geometrically complex parts
are difficult to form economically with conventional forming processes like deep drawing or
stretching. Therefore, new concepts like hydro-mechanical forming or incremental sheet metal
forming were developed. In order to select the optimal forming process the production costs as well
as the environmental aspects like lubrication, noise, pollution and energy per produced part have to
be considered.
The paper is focused towards the comparison of conventional deep drawing (DD) process aimed
for forming the pyramid-shaped part with single point incremental forming technology (SPIF). The
economical and ecological aspects affecting the successful forming by both concepts are
determined. Comparative evaluation was established in order to present advantages and drawbacks
of each analysed technology.
Modelling Intergranular Stress Corrosion Cracking in Simulated Three-Dimensional Microstructures
Authors: Jivkov Andrey P. , Stevens Nicholas.P.C. , Marrow T.James
Published: March 2009

Microstructure can have a significant effect on the resistance to intergranular stress
corrosion cracking. Certain grain boundaries are susceptible to corrosion while others have high
resistance and may form crack bridging ligaments as the crack deviates around them. To investigate
the mechanics of crack bridging, 3D computational model has been previously developed. An
extension to the model, to include stress corrosion crack growth kinetics is presented in this paper.
An analysis of the effects of resistant grain boundary fraction demonstrates that the bridging
ligaments can significantly retard short crack propagation rates. Increasing the fraction of resistant
boundaries is shown to improve microstructure resistance by reducing the crack propagation rate.
Interface Oxidation Process of ZrO2-8%Y2O3 / CoNiCrAlY Thermal Barrier Coating System
Authors: Waki Hiroyuki , Kobayashi Akira
Published: March 2009

Thermal barrier coating (TBC) of a gas turbine blade suffers from high temperature
oxidation. It is known that thermally growth oxidation (TGO) grows at the interface between ZrO2-
8%Y2O3 and CoNiCrAlY, and the TGO degrades the adhesive strength. The purpose of this study is
to clarify the TGO growth process. Thermal aging tests of ZrO2-8%Y2O3 / CoNiCrAlY TBC
systems under various temperature conditions were carried out. TGO growth process was observed
by an electron probe micro analyzer (EPMA). Both TGO of Al and TGO of other elements were
examined, and the thickness of the TGOs were examined. Results are summarized as follows. (1)
The delamination occurred at a ZrO2-8%Y2O3 layer beside the interface. (2) The growth rate of
complicated TGO which consisted of Co, Ni and Cr increased with an increase of temperature.
However, the complicated TGO wasn’t related with the delamination life. (3) The delamination
could occur if the thickness of Al TGO increased more than about 3 μm.
Irradiation Effect on Mechanical Properties and Oxidation Behavior of Nano-Filamentary Copper-Silver Composites
Authors: Choi Y. , Choe J.I. , Choo Kee Nam , Kim D.S.
Published: March 2009

Quasi-nano filamentary copper-silver composites were irradiated and annealed to study
irradiation degradation behavior. The specimen was irradiated in CT hole of HANARO of KAERI
for 36 days at 320°C with the maximum neutron flux of 4.8x1020 n/cm2 (E>1.0 MeV). The gamma
heating rate was in the range of 2.0-6.45 W/gm. Irradiation embrittlement was observed. Hardness
determined by nano-indentation technique were 32.3 GPA for as-received condition, however, it
decreased 24.6 GPa due to gamma heating, which was above the value of the specimen with same
annealing effect without irradiation. Weight change of specimen with oxidation increased with
annealing time, temperature and amount of dose 0.21-0.27 mR/h. Hardness change of the irradiated
specimen followed by annealing was significantly dependent upon amount of dose of the specimen.
Strain Loci in Stretch Flange Forming of Aluminum Alloys
Authors: Chen Zeng Tao , Worswick Michael J.
Published: March 2009

Stretch flange forming experiments of AA5182 and AA5754 sheet alloys were performed
to characterize the forming properties. Identical blanks with the same cutout radius were deformed
to 25, 50, 75, and 90% of the measured minimum punch depth to fracture. Strain development
during stretch flange forming was tracked through strain measurement of the recovered
deformation-interrupted samples. Finite element modeling of stretch flange forming was performed,
and the resulted strain distribution along the stretch flange profile was compared to the experimental
results. Good agreement was observed between the numerical and experimental results. Two failure
modes observed in the stretch flange experiments, inner edge necking and circumferential cracking
in sidewall, were related to the measured strain locus and sheet thickness.
Material Properties of Thick Aluminum Coating Made by Cold Gas Dynamic Spray Deposition
Authors: Lee Jae Chul , Chun Doo Man , Ahn Sung Hoon , Lee Caroline S.
Published: March 2009

Cold gas dynamic spray is a relatively new coating process by which coatings can be
produced without significant heating during the process. Cold gas dynamic spray is conducted by
powder sprayed using supersonic gas jet, and generally called the kinetic spray or cold spray. Its low
process temperature can minimize the thermal stress and also reduce the deformation of the substrate.
In this study, thick or macro scale deposition was studied while most researches on cold-spray have
focused on micro scale coating. Measured material properties of macro scale deposition layer showed
that elastic modulus and hardness were lower and electrical resistivity was higher than those of
reference substrate material. The main causes of changed material properties were investigated by
FE-SEM (Field Emission Scanning Electron Microscope) and EDS (Energy Dispersive X-ray
Spectrometer) data. In this result, porous micro structure generated by imperfect plastic deformation
might cause decrease in elastic modulus and hardness of the deposition layer by cold spray, and
oxidized Al particles increased the electrical resistivity.
Equal Channel Angular Extrusion of Zinc-Aluminium Metal Matrix Composites
Authors: Mak Jonathon , Wuhrer Richard , Booth Norman , Fanos Paul , Heness Greg , Yeung Wing Yiu
Published: March 2009

Equal channel angular extrusion (ECAE) was employed in an attempt to develop
nanostructural metal matrix composites with homogenized distribution of reinforcing particles. Zn-
Al metal matrix composites reinforced with 5 μm SiC particulates were produced by casting
method. A non-uniform distribution of the reinforcing particles was evident in the metal matrix.
With repetitive shear deformation imposed via the ECAE process, substantial structural
improvement was achieved and the reinforcing particulates were de-clustered into a finely dispersed
distribution throughout the metal matrix. The homogeneity of the particle distribution was studied
by the Quadrat method and the skew factors were determined. It was found that the skew factors
were substantially reduced after 8 extrusion passes, showing the homogeneity of the particle
distribution was greatly improved in the composites.
A Study on Structural Safety Evaluation of Jet Vane under Severe Thermal and Mechanical Loadings
Authors: Park Sung Han , Kim Jae Hoon , Kim Won Hoon , Moon Soon Il
Published: March 2009

When jet vane is exposed to exhaust gas and deflected at a typical angle, side force is produced
and the missile is controlled. The vane is subjected to severe thermal and mechanical loadings by combustion
gas. In this study, the high temperature tension tests of refractory metals, 3-D nonlinear numerical
simulations and motor firing tests were performed to evaluate structural safety factor of the jet vane. The
structural safety factor of jet vane was evaluated by comparing the numerical results with cold and hot
structural tests of jet vane system. It has been found that a shaft supports most of thermal and mechanical
loadings on the system and is structurally safe below 1400°C. From the comparison of firing tests and
numerical results, the evaluation criterion of structural safety using the load and shaft deformation is more
useful than using the equivalent stress.
Evaluation of Flexural Displacement in Piezoelectric Actuators Considering the Thermal Deformation
Authors: Woo Sung Choong , Goo Nam Seo
Published: March 2009

In this article, the flexural displacement of plate-type piezoelectric composite actuators
(PCA) with various lay-up configurations has been evaluated considering the thermal deformations
induced by a temperature drop using a three-dimensional finite element simulation. The results
reveal that the flexural displacement of PCA subjected to electrical loadings is significantly affected
by their lay-up configurations, the thickness of constituent PZT ceramic and applied boundary
conditions, which is associated with the location of the neutral plane by moment equilibrium and
the bending stiffness of PCA. For the displacement performance of PCA, an adequate choice of layup
configuration together with the proper thickness of PZT ceramic is required.
A Study on the Measuring Device of Muzzle Velocity Using Magnetic Field Gradient Sensor
Authors: Chae Je Wook , Choi Eui Jung
Published: March 2009

In the conventional weapon system, such as gun and small arms, it is a general trend that
for maximization of its performance and enhancement of its effectiveness, the fire control system;
FCS is developed and applied with the guns and small arms in the world. The FCS of the small arms
for infantry man is composed of a few of sensors for acquisition of input data of FCS, such as range
measurement, position sensing of weapon, temperature, etc., computer, displayer and power pack,
and also the air burst ammunition is developed in parallel for the maximization of effectiveness. Since
setting fuse of the flight time for the air burst ammunition is adapted for next rifle, the measuring
device of the muzzle velocity is needed to overcome the variation of muzzle velocity due to producing
procedures and the differences of the using temperatures and so maintain the burst position accuracy.
This paper contained the technical information on the development of the measuring device of muzzle
velocity, which designed in compact & light weight configuration with reliability and accuracy.
Development of New Evaluation Method for Adhesive Strength between Microsized Photoresist and Si Substrate of MEMS Devices
Authors: Ishiyama Chiemi , Sone Masato , Higo Yakichi
Published: March 2009

An evaluation method for adhesive bending and shear strengths between microsized
components and silicon substrate were developed to quantitively determine micro-sized adhesive
strength for micro-electro mechanical system (MEMS) devices. Cylindrical shape is employed as a
micro-sized adhesive specimen to simply analyze adhesive stresses of both shear and bending.
Micro-sized adhesive tests between micro-sized SU-8 cylindrical specimen and Si substrate were
performed using a mechamical testing machine for micro-sized material that has developed by our
group. Delamination of all the specimens occurred within the SU-8 near by the substrate in a
brittle manner under both bending and shear loading conditions. The adhesive bending stress is
57 % lower than the bend strength of the SU-8 material. The adhesive shear strength under bend
loading is 15 % lower than the adhesive strength under shear loading and the delamination surface
is different in each loading mode. All the results suggest that some defects at the interface must
induce the stress concentration, which may make the apparent strength of SU-8 decrease.
In Situ Synthesis of TiAl Matrix Composites by Melting Route
Authors: Choi Bong Jae , Sung Si Young , Kim Young Jig
Published: March 2009

TiAl alloys Al composition range between 45 and 49 at%, includes γ-TiAl and α2-Ti3Al,
are an emerging high temperature materials which has higher specific strength, oxidation ratio and
specific modulus than Ni base superalloy. In this study, TiAl alloys were manufactured by plasma arc
melting (PAM) and then TiAl and granular boron carbide were in-situ synthesized in PAM method
again. The in-situ synthesized TiAl matrix composites were investigated by using X-ray
diffractometer, optical microscope, and electron probe micro-analyzer.
The Effect of Technological Condition on Electrical Properties of ITO Films
Authors: Zeng Sheng Nan , Liu Jia Xiang , Zhang Nan
Published: March 2009

The transparent ITO multi-layers films were fabricated on quartz glass substrate by colloid
dip-coating technique from indium metal ingots and stannic chloride. It was systematically
studied that the effect of the electrical properties of the ITO on doped Sn in quantitative change,
different dip-coating technological conditions such as thermal treatment process, coating number
plies by four-probe instrument. From the 5 wt. % Sn to 20 wt. % Sn, with the amount of doped
Sn increasing, the sheet resistance of ITO was up to minimum and then increased. Sintering
temperature and holding time were the reasons for the electrical properties of the ITO films,
when other parameters are unaltered. It is also concluded that coating number plies was play an
important role on electrical properties of ITO films by sheet resistance. From the results of
research, it can be seen that the multi-layer films has optimum characteristics, whose sheet
resistance is 117'/□, when the use level of Sn is 10%wt,heated in 800°C 15min with repeated
dip-coating seven times..
Deformation Behavior of Reinforced Concrete Members with Prefabricated Fiber Laminate Composites
Authors: Hong Young Gyun , Hong Gi Sub , Kang Jae Kyu , Hwang Kyu Hong , Yoon Jeong Bae
Published: March 2009

The innovative method based on prefabricated fiber laminate composites bonded to
lightweight precast panel was applied for quality control of RC strengthening members. The
experimental investigations for this method were presented for flexural member. Three different
groups such as control group without strengthening, conventional fiber bonding group and innovated
PFLC group bonded to precast panel. Tested results showed good or better capacities comparing to
conventional strengthening method for flexural members. This investigation indicate that good
enhancement with respect to quality control and reliability can be possible by the installation and
epoxy injection with prefabricated panel using fiber laminate composites.
Multi-Scale Modelling Scheme for Carbon Nanotube Reinforced Metal Matrix Composites
Authors: Pham Quang , Yoon Seung Chae , Bok Chun Hee , Kim Hyoung Seop
Published: March 2009

Carbon nanotubes (CNTs) have been the subject of intensive studies for applications in the
fields of nanotechnologies in recent years due to their superior mechanical, electric, optical and
electronic properties. Because of their high Young’s modulus (≈ 1 TPa), tensile strength (≈ 200 GPa)
and high elongation (10-30%) as well as high chemical stability, CNTs are considered to be attractive
reinforcement materials for light weight and high strength metal matrix composites. In this paper, we
described a scheme for multi-scale modeling for the elastic and plastic properties of CNT/metal
nanocomposites using the numerical analyses of the three-dimensional finite element method based
on the continuum mechanics of a unit cell. In particular, the quantitative effects of the distribution and
the array of the CNT reinforcement (viz. cross-over, vertical and horizontal distributions) on the
elasticity and plasticity of the nanocomposites were investigated and the anisotropic characteristics of
elasticity and plasticity of the nanocomposites were linked with the extremely high aspect ratio of
CNTs.
Bending Property of Sandwich Beams with MWNTs/Polymer Nanocomposites as Core Materials
Authors: Yeh Meng Kao , Hsieh Tsung Han
Published: March 2009

The bending property and failure mechanism of sandwich beams were investigated. The
multi-walled carbon nanotubes (MWNTs) were used as the reinforcement in the MWNTs/polymer
nanocomposites and the epoxy and phenolic resins were used as the matrix. The MWNTs/polymer
nanocomposites were used as the core materials of sandwich beams, which had faces made by
graphite/epoxy laminates. In experiment, the hot press method was applied to fabricate the
MWNTs/polymer nanocomposites and graphite/epoxy laminates. The weight percentage of MWNTs
in core materials and the fiber orientation of face laminates were varied to assess their effects on the
bending properties of the sandwich beams. The failure mechanism of sandwich beams with two kinds
of polymer core materials was investigated. In analysis, the finite element method was used to obtain
the bending behavior of the sandwich beams. The numerical results were in good agreement with the
experimental ones.
Heat Treatment and Impact Testing of Composite Wires
Authors: Kientzl Imre , Dobránszky János , Ginsztler János
Published: March 2009

The reinforcement of high voltage electric power cables is a promising
application field of the composite wires. The temperature of the power cables can reach 200-300 °C
due to an over-loaded electrical grid. The composite wires have to stand these high temperatures for
a long time in the power cables. Long term heat treatments have been done to examine the
eligibility of the composite wires. After heat treatment impact test was applied to measure the
changes of the mechanical properties of composite wires. With the instrumented impact tester the
process of the failure was examined. In this paper the continuous production method of ceramic
fibre reinforced metal matrix composite wires and their properties are shown.
Application of Magnetostrictive Transducer for the Long-Range Guided Wave Inspection
Authors: Cheong Yong Moo , Kim Shin , Jung Hyun Kyu
Published: March 2009

The leakage of the pipes is a major issue for the safety of industrial structures. However,
in many cases, because of their geometrical complexity and inaccessibility, it is difficult to inspect
them by the conventional NDE method. A long-range guided wave inspection, thus, is an option to
inspect them. A torsional vibration mode, T(0,1) shows many advantages in a long-range guided
wave examination of a pipe, such as no dispersion characteristic, no radial displacement and low
attenuation. However, it is not easy to fabricate a transducer with an array of piezoelectric elements
for generation of torsional vibration mode and even expensive. Recently a magnetostrictive metal
strip sensor was used for a generation of the torsional vibration modes in a pipe and this technique
has shown several advantages for practical applications. This study investigated the applicability of
a long-rang guided ultrasonic method to the detection of artificial notches even in the presence of
various foreign objects.
Characterization of Composite Materials Using an Inverse Technique
Authors: Hwang Shun Fa , Yeh Cyuan Kuan , He Rong Song
Published: March 2009

Combining vibration testing and numerical method is a potential inverse technique for
determining elastic constants of materials because of its nondestructive characteristic, single test,
and producing average properties. In order to simplify the modeling processes and to reduce
complicated derivation in the numerical method, the combination of finite element analysis and
optimum design is adopted in this work. A finite element package, ANSYS, is used to do the modal
analysis of the composite plate. A hybrid genetic algorithm, in which a simulated annealing
mutation process and adaptive mechanisms are added to the real-parameter genetic algorithm, is
used to search the possible elastic constants. After obtaining the natural frequencies of the
composite plates from vibration testing, this inverse technique could predict the elastic constants of
the composite plate. The inverse technique is verified by comparing with other methods and by
determining the elastic constants of aluminum plates, and the excellence of including the hybrid
genetic algorithm is proved. The results also indicate that the present technique could obtain very
accurate elastic constants of composite plates.
Fatigue Life Calculation of Metallic Materials
Authors: Walther F. , Eifler Dietmar
Published: March 2009

In stress-controlled load increase and single step tests besides the plastic strain amplitude
the changes of the temperature and the electrical resistance caused by cyclic plastic deformation
were measured. Temperature and resistance measurements don’t require a defined gage length and
can be applied also on components even under service loading to ensure economic and safe
operation conditions. On the basis of Morrow and Basquin equations a physically based fatigue life
calculation “PHYBAL” was developed. This new short-time procedure allows a rapid and precise
calculation of Woehler curves with data of one load increase and two single step tests.
A Study on Experimental Evaluation for Fracture Behavior of Carbon Steel Pipes for High Pressure Service with Local Wall Thinning
Authors: Ahn Seok Hwan , Seok Kum Cheol , Nam Ki Woo
Published: March 2009

The locally wall thinned phenomenon of pipes is simulated as metal loss due to
erosion/corrosion. Therefore, fracture behaviors of pipes with local wall thinning are very important
for the integrity of nuclear power plant. In this study, monotonic bending tests without internal
pressure are conducted on 1.91-inch diameter Schedule 80 STS370 full-scale carbon steel pipe
specimens. We investigated fracture strengths and failure modes of locally wall thinned pipes that
welded and unwelded by four point bending test. From test results, we could be divided three types
of failure modes.
Influence of Impurities to Deformation Behavior in Magnesium Single Crystal
Authors: Kutsukake Ayaka , Ando Shinji , Tsushida Masayuki , Kitahara Hiromoto , Tonda Hideki
Published: March 2009

Generally, plastic deformation of magnesium alloys is difficult at room temperature. In
order to improve formability of magnesium, impurity elements in magnesium were reduced by
vapor deposition technique. Inductively coupled plasma atomic emission spectrometry (ICP-AES)
was applied to the determination of trace elements in refined magnesium. To investigate influence
of impurity element to deformation behavior, high purity magnesium single crystals were prepared.
When the magnesium single crystals are stretched in <11-20> direction, {11-22} <-11-23>
pyramidal slips were activated just after yielding in the range of 77K to 293K. The yield stress of
high purity magnesium was a half of the stress in raw magnesium.
Extending Endurance for the Friction Coefficient Development of Automobile Wiper Blade
Authors: Shin Wae Gyeong , Lee Soo Hong , Jung Do Hyun , Choi Young Woo
Published: March 2009

Wiper blade is one of inexpensive automotive components, but the component is very
important part considering car safety for securing automotive visual field. Therefore study for
securing longer endurance of wiper blade was proceeding, that is about variables effecting on
endurance. In this paper, it was proved that the effect to extend endurance could be acquired by
securing proper friction coefficient. Be compared endurance in Weibull distribution that is reliability
technique and seized effect about blade pressure distribution, contact pressure, blade rubber surface
treatment etc. for securing proper friction coefficient. Relation between these variables was cleared
through test. Also, designed and proposed tester for measuring friction coefficient of wiper blade.
Influence of the Welded Joint on the Mechanical Behavior of Steel Piles during Static and Dynamic Deformation
Authors: Jang Gab Chul , Chang Kyong Ho , Lee Chin Hyung
Published: March 2009

During manufacturing the welded joint of steel structures, residual stress is produced and weld
metal is used inevitably. And residual stress and weld metal influence on the static and dynamic mechanical
behavior of steel structures. Therefore, to predict the mechanical behavior of steel pile with a welded joint
during static and dynamic deformation, the research on the influence of the welded joints on the static and
dynamic behavior of steel pile is clarified.
In this paper, the residual stress distribution in a welded joint of steel piles was investigated by using
three-dimensional welding analysis. The static and dynamic mechanical behavior of steel piles with a welded
joint is investigated by three-dimensional elastic-plastic finite element analysis using a proposed dynamic
hysteresis model. Numerical analyses of the steel pile with a welded joint were compared to that without a
welded joint with respect to load carrying capacity and residual stress distribution. The influence of the
welded joint on the mechanical behavior of steel piles during static and dynamic deformation was clarified by
comparing analytical results
Variation of Material Properties of Piezoelectric Ceramics due to Electric Loading Evaluated by Resonance Frequency
Authors: Mizuno Mamoru , Odagiri Nozomi , Okayasu Mitsuhiro
Published: March 2009

In the present paper, lead zirconate titanate (PZT) and lead titanate (PT) piezoelectric
ceramics were subjected to both high electric field (which is higher than the coercive electric field)
with low frequency and low electric field with high frequency (which is the resonance frequency).
After applying certain electric field systematically, resonance and anti-resonance frequencies and an
electrostatic capacity were measured by means of an impedance analyzer, and an electromechanical
coupling coefficient, a dielectric constant, an elastic coefficient and a piezoelectric constant were
evaluated from the frequencies and capacity measured. Then variation of the material properties in
process of time was investigated experimentally, and the dependence of the variation of the properties
due to mainly domain switching on conditions of applied electric field was elucidated.
Impact Damage Resistance of Glass/Epoxy Laminates with Embedded Shape Memory Alloy
Authors: Kang Ki Weon , Kim H.J. , Kim J.H. , Kim Heung Seob , Kim Yong Su , Do Young Min
Published: March 2009

This paper deals with the damage resistance of glass/epoxy laminates with embedded
shape memory alloy (SMA) subjected to low-velocity impact at various temperatures. For this goal,
the impact tests were performed by using an instrumented impact-testing machine at three
temperatures: +20°C, -10°C and -40°C. And the resultant damages were inspected through the
scanning acoustic microscope (SAM). Also, based on the impact force history and the damage
configuration, the impact resistance parameters were employed to evaluate damage resistance of
laminates with embedded SMA wires. As results, it was found that the damage resistance of
glass/epoxy laminates with embedded SMA wires is dependent on the service temperature.
The Effects of Hot Isostatic Pressing on Aluminium Castings
Authors: Ostermeier Markus , Hoffmann Hartmut , Werner Ewald
Published: March 2009

Since the early 1960s hot isostatic pressing (HIP) was used to improve the quality of
castings made of various alloys. The closure of pores, originating from the casting process, is
considered as the main source of these improvements. For the aluminium alloy Al-9Si-3Cu
specimens for tensile testing were machined from castings either squeeze casted and heat treated to
T4 and T6 conditions or investment casted. The effect of HIP on density, roughness and mechanical
properties was investigated. The density and roughness of the squeeze casted specimens did not
change remarkably and their tensile strength became worse, because the initial heat-treatment-state
was destroyed by HIP. The investment casted specimens became denser and roughness became
worse due to closure of pores near the surface. Although roughness after HIP was higher than in the
initial state, tensile strength was improved significantly by HIP, because of closure of the pores in
the specimen.
Investigation on the LPCVD LTO Thin Film as a New Dielectric Layer for the Future ULSI Devices
Authors: Ahn Seung Joon , Ahn Seung Joon , Park Chul Geun
Published: March 2009

As the design rule goes down sub-70 nm for the ULSI devices, the total thermal budget that
the device can take during the fabrication is also reduced very much. Hence, in this work, we propose
a novel low-temperature LPCVD process for formation of thin dielectric oxide film which does not
need SiH2Cl2 gas. We have also evaluated the electrical reliability of the film by making the
capacitors with oxide-nitride-oxide (ONO) structure. The leakage current of the new oxide was
similar to that of the high-temperature wet oxide until the electric field is lower than 5 MV/cm. When
the film was annealed by N2 gas, however, it has shown much better characteristics over the entire
range.
Precipitation Behavior of MX Phase in Cr-Mo-N-X(X=V,Nb,Ti) Ferritic Steels
Authors: Bae Deuck Seung , Jung Woo Sang , Hong Kyung Tae , Lee Kyung Sub
Published: March 2009

The precipitation behavior of MX nitrides during aging was investigated for Cr-Mo-N-X
(X=V,Nb,Ti) ferritic steels. MX nitrides, which are finely dispersed in the matrix of Cr-Mo ferritic
heat resistance steel, increase the creep strength of the steels by the precipitation strengthening
mechanism. However, MX particles usually coarsen during aging, and this results in a decrease of
creep strength. In order to clarify the coarsening process of MX particles, TEM samples were
prepared from the aged for up to 3000hours specimens. During the aging, V, Nb and Ti containing
nitrides (called MX nitrides) were precipitated out. From TEM observation, particle size
distribution was confirmed and size distribution follows a typical log-normal distribution. The
observed coarsening behavior well agreed with the calculated coarsening behavior of precipitates by
Oswald ripening equation.
Effect of In Situ Formed Spinel Phase on the Mechanical Properties of Zirconia Ceramics
Authors: Yang Z. X. , Yoon Jeong Bae , Hwang Kyu Hong , Lee J.K. , Jun B.S.
Published: March 2009

The reaction-sintered zirconia-alumina and zirconia-spinel ceramics having low firing shrinkage
were prepared from ZrO2(Ca-PSZ)/Al and ZrO2(Baddellyite)/MgAl powder mixtures via the
attrition milling and the effect of the characteristics of used raw powders was investigated.
Flaky Al powders mixed with coarse Ca-PSZ powders was not effectively comminuted due to
lower hardness of zirconia powders. So by using the alumina ball media or coarse Al2O3 powders
rather than Al, the milling efficiency could be much more increased. When fused Ca-PSZ powder
was reaction-sintered with Al at 1550 for 3 hours, the reaction-sintering and densification were
somewhat difficult because the Ca-PSZ/Al powder mixture was not effectively comminuted. And
the Ca ion in Ca-PSZ grains diffused into alumina grains during sintering so that the unstabilization
of Ca-PSZ body was occurred which gave the cracks in the specimens.
But when MgAl alloy powder was added to monoclinic zirconia, Mg and Al became to oxide at
first and subsequently converted to spinel(MgAl2O4) during heating and finally unreacted MgO
seemed to stabilize the zirconia. The oxides which formed at the oxidation process would have very
fine grain size so that the reaction sintering was more effective to densification and homogeneous
microstructure. The mechanical properties of reaction-sintered stabilized zirconia/spinel composite
were better than only MgO stabilized zirconia. Sintering behavior in reaction and mechanical
properties of sintered body were examined, with emphasis on the relations between spinel formation
and mechanical properties.
Enhancement of Surface Property by Low-Energy Laser Peening without Protective Coating
Authors: Sano Yuji , Adachi T. , Akita Koichi , Altenberger I. , Cherif M.A. , Scholtes Berthold , Masaki Kiyotaka , Ochi Yasuo , Inoue Tatsuo
Published: March 2009

Laser peening without protective coating (LPwC) has been applied to metallic materials
using low energy pulses of a Q-switched and frequency-doubled Nd:YAG laser. Compressive
residual stresses of several hundred megapascals were imparted on the surface of the materials.
Redistribution of the residual stress in the top surface due to thermal loading was evaluated
non-destructively by synchrotron radiation of SPring-8. Accelerating stress corrosion cracking (SCC)
tests showed that LPwC prohibited SCC of sensitized materials. LPwC largely prolonged the fatigue
lives of titanium alloys, aluminum alloys and austenitic stainless steels.
Synthesis of High Aspect Ratio Iron Oxide Nanoparticles Using Water in Oil Microemulsion
Authors: Suhafri M. , Yaacob Iskandar Idris
Published: March 2009

High aspect ratios maghemite of iron oxide nanoparticles were prepared using water in oil
microemulsions. A four component microemulsion system with cationic HTAB, n-butanol, noctane,
and salt solution was used. Precipitations of iron oxide were initiated by mixing a
microemulsion system containing Fe2+ with another microemulsion system containing OH-. The
resulting particles were characterized using XRD, AGM and TEM. The XRD result showed the
formation of maghemite. TEM showed that the average length of needle shaped particles increased
from 28 nm up to 42 nm as the aging time was increased from 4 to 24 hours while the average
diameter spherical particle remained at around 8 nm. The AGM confirmed that the particles are
superparamagnetic.
Stress Relaxation in Selected Magnesium Alloys
Authors: Trojanová Zuzanka , Lukáč Pavel , Kim Kyung Hyun
Published: March 2009

The stress relaxation phenomena in magnesium alloys, containing Al, Sr and Ca solutes
have been investigated. The samples were deformed at a constant initial strain rate at various
temperatures between room temperature and 300 °C. Stress relaxation, i.e. a decrease in the stress
with time, was measured at various stresses and at various temperatures. The stress relaxation curves
were analysed as a function of the internal stress at the beginning of the relaxation and the test
temperature.
Mechanical Properties of 91% Tungsten Alloy
Authors: Song Wei Dong , Liu Hai Yan , Ning Jian Guo
Published: March 2009

The tensile tests and the three-point bending tests have been conducted to investigate the
crack initiation and propagation and the fracture behavior of 91W-6.3Ni-2.7Fe with three kinds
grain sizes of 1~3μm, 10~15μm and 30~40μm. SEM was introduced to analyze the grain sizes, the
micro-defects, the deformations and the fracture behaviors of tungsten alloys. The test results show
that under the same loading conditions, the crack initiation and the crack propagation are not only
related to grain size, but also related to the contiguity of tungsten grains and the interface between the
tungsten grains and the matrix.
Fatigue Behaviour of Extruded Mg2Si-Reinforced Magnesium Alloy
Authors: Uematsu Yoshihiko , Tokaji Keiro , Kamakura Mitsutoshi
Published: March 2009

Rotary bending fatigue tests were conducted in order to investigate the fatigue behaviour
and fracture mechanisms of extruded Mg2Si-reinforced magnesium (Mg) alloys. Mg2Si particles were
mixed with Mg alloy (AZ31) powder to form billets and then extruded at two different working
temperatures of 685K and 646K, where the materials extruded at high and low temperatures were
denoted as Mg2Si-H and Mg2Si-L, respectively. The grains of the matrix were finer in Mg2Si-L than
in Mg2Si-H. The proof stress and tensile strength were independent of working temperature and
increased compared with a conventional extruded AZ31 alloy, with a decreased in ductility. The
fatigue strength of Mg2Si-H was almost the same as that of the extruded AZ31 alloy, but the fatigue
limit was lower, while the fatigue strength of Mg2Si-L was higher than that of Mg2Si-H and the
extruded AZ31 alloy. Both crack initiation and crack growth resistances in Mg2Si-L were improved,
which could be attributed to high bonding strength of Mg2Si/Mg interfaces and fine grain refinement
of the matrix.
Etch Pit Observation of Dislocations in Early Deformation of Cu-Al Alloy and Pure Mg Polycrystals
Authors: Nishimura Yoshito , Ono Nagato , Miura Sei
Published: March 2009

In order to make clear the micro-yielding mechanisms of polycrystalline metals including
twins, the movement of dislocations in the surface grains of Cu-6.8at%Al alloy and pure Mg
polycrystals during the early stages of deformation was directly observed by using etch pit technique.
The fresh dislocations multiply from the Frank-Read sources within the grains, and pile up against the
twin and grain boundaries of two kinds of specimens. The pile-up dislocations on the primary and/or
secondary slip planes are also confirmed in Cu-6.8at%Al alloys. Especially during the compressive
loading for pure Mg, the occurrence of deformation twins is remarkable with an increase of strain rate,
whereas the distribution of fresh dislocations tends to decrease in the surface grains. The present
results suggest that the effect of twin boundaries on micro-yielding is almost equivalent for that of
grain boundaries, which act as barriers to moving dislocations even in the pre-yield deformation.
Fatigue Behaviour of Type 444 Stainless Steel at Elevated Temperatures
Authors: Akita Masayuki , Nakajima Masaki , Uematsu Yoshihiko , Tokaji Keiro
Published: March 2009

This paper describes the fatigue behaviour at elevated temperatures in a ferritic stainless
steel, type 444. Test temperatures evaluated were ambient temperature, 673K and 773K in
laboratory air. Fatigue strength decreased at elevated temperatures compared with at ambient
temperature. At all temperatures, cracks were generated at the specimen surface due to cyclic slip
deformation, but fractographic analysis revealed a brittle features in fracture surface near the crack
initiation site at elevated temperatures. Cracks initiated earlier at elevated temperatures than at
ambient temperature and subsequent small cracks grew faster at elevated temperatures even though
the difference in elastic modulus was taken into account, indicating the decrease in crack initiation
resistance and crack growth resistance. The observed decrease in both resistances was discussed in
relation to the 748K(475C) embrittlement in ferritic stainless steels.
The Static and Cyclic Deformation Behaviours Mg-Y2O3 Nanocomposites
Authors: Goh G.S. , Wei Jun , Gupta Manoj
Published: March 2009

Mg-Y2O3 nanocomposites were synthesized by disintegrated melt deposition method
(DMD). Tensile tests and constant stress amplitude fatigue tests were carried out on Mg
nanocomposites with 0.5, 1.0 and 2.0 volume percentages of reinforcements. Yield strengths of the
nanocomposites were found to increase with higher volume fraction of Y2O3. Both unreinforced Mg
and the Mg nanocomposites were found to strain harden upon cycling. The hardening behaviour
was more intense in the nanocomposites.
Effect of Nitriding on Fatigue Crack Initiation and Fatigue Crack Propagation Retardation in Ni-Cr-Mo Steel
Authors: Lim Bokkyu , Choi Young Woo
Published: March 2009

Effect of nitriding on fatigue crack initiation and growth rate has been studied on Ni-Cr-Mo
steel. Specimens were nitrided for 15hr at 680°C. The fatigue limit of nitrided specimens were
superior to those of annealed(680°C, 15 hr) specimens. Based on detailed observations of slip band
and micro crack initiation, it is concluded that the excellent fatigue limit of nitrided specimens is
attributed to improved slip initiation resistance by nitriding. The characteristic of fatigue crack growth
rate of nitrided specimens was investigated by comparing with those of annealed specimens. It was
found that by nitriding the crack growth rate was markedly decreased and the threshold stress intensity
factor range was improved. It is concluded that the excellent fatigue limit of nitrided specimens is
also attributed to improved fatigue crack growth rate and threshold stress intensity factor range by
nitriding.
Experimental Investigation on the Fatigue Strength of the Replacement Repair Welded Joints
Authors: Chang Kyong Ho , Park H.C. , Lee Chin Hyung , Jang Gab Chul , Choi E.H.
Published: March 2009

In recent years, the replacement repair welding, which repairs damaged steel girder bridges
by replacement of the damaged sections with new steel plates through cutting and welding under
in-service conditions, is spotlighted for its brilliant features, i.e. it can be achieved without incurring
traffic dislocation. However, the mechanical behavior of the welded joints under cyclic loads due to
the traffic which passes along the girder bridges is not clarified. In this paper, the fatigue strength of
the replacement repair welded joints was investigated in order to improve reliability in the repair
welded joints. Steel plate was extracted from the old steel girder bridge; then was welded with new
steel plate to construct specimen with the replacement repair welded joints. Flux Cored Arc Welding
(FCAW) process was used to fabricate the double "V" butt joints. Fatigue tests were conducted using
a servo hydraulic controlled 50tonf capacity UTM with a frequency of 5Hz under constant amplitude
loading. The fatigue strength of the replacement repair welded joints was analyzed in detail.