bluuebunny/crossref_metadata_2025 huggingface dataset:
Two-Dimensional Analysis of Fretting Fatigue of Functionally Graded Materials
Authors: Ke Liao Liang , Wang Yue Sheng
Published: March 2009

Fretting is a major cause of surface damage and fretting fatigue crack initiation at the
interface between contact materials subjected to small oscillatory movements. In the present paper, a
multi-layered model is developed to analyze fretting fatigue of functionally graded materials (FGMs)
with arbitrarily varying shear modulus under plane strain-state deformation. Based on the fact that an
arbitrary curve can be approached by a series of continuous but piecewise linear curves, the FGM is
divided into several sub-layers and in each sub-layers the shear modulus is assumed to be a linear
function while the Poisson’s ratio is assumed to be a constant. With the model, the problem of fretting
contact of two similar functionally graded coated cylinders is investigated. By using the transfer
matrix method and Fourier integral transform technique, the problem is reduced to two uncoupled
Cauchy singular integral equations. The tangential contact pressures in the slip and stick zones are
calculated by solving the equations numerically. The results show that appropriate gradual variation
of the shear modulus can significantly alter the pressures in the contact zone. This may lead to
suppression of fretting fatigue cracks at the edges of the contact zone and thus modify the fretting
contact damage.
A Three-Dimensional Finite Element Model of Hydraulic Progressive Damage
Authors: Xue Bing , Wu Heng An , Wang Xiu Xi , Lian Zhi Long , Zhang Jin , Zhang Shi Cheng
Published: March 2009

Three-dimensional finite element simulations were carried out to investigate the hydraulic progressive damage and associated flow behavior in rock. In this study cohesive elements were used to simulate the damage of rock. A three-dimensional coupled pore fluid flow and stress model was proposed. The commercial engineering software ABAQUS is employed to simulate the damage process in rock along several predefined paths. A user-subroutine named FLOW was developed to enhance the capability of ABAQUS to deal the moving loadings. With the proposed coupling model, we studied the stress distribution, the pore pressure, the fluid loss, the geometry of the progressive damage. The results show that the length and the width of the path of the progressive damage are strongly influenced by both the hydraulic pressure and the injection time. The results provide good interpretation and understanding of the mechanism of hydraulic progressive damage in rock. This study is very useful and important to the oil engineering and some other rock engineering fields.
An Energy-Based Approach for Fatigue Crack Growth
Authors: Fu De Long , Zhang Li , Jin Cheng
Published: March 2009

A fatigue crack growth model under constant amplitude loading based on the total plastic
energy dissipation per cycle ahead of the crack was proposed. With the energy balance concept, the
crack growth rate was correlated with the total plastic dissipation per cycle, and the total plastic
dissipation per cycle was obtained through 2-D elastic–plastic finite element analysis of a stationary
crack under constant amplitude. The predictions of the model were in good with the experimental
results.
Passivation Cracking Analyses of Micro-Structures of IC Packages
Authors: He Yu Ting , Li Hong Peng , Shi Rong , Li Feng , Zhang G.Q. , Ernst L.J.
Published: March 2009

The passivation cracking of Micro-structures of IC packages is studied by maximum
principal stress theory using a certain 2D FEM model with different design parameters, pitch of lines,
width of line, thickness of epoxy, thickness of dielectric layer, thickness of glue, the glue material’s
yielding stress and Aluminium yielding stress (following as “d”, “w”, “t_epo”, “t_Teos”, “t_glue”
“sy_glue” and “sy_al” respectively). For different critical process steps, the final process temperature
is acted as a representative parameter to analyze its impact. Furthermore, Response Surface Model
(RSM) of principal stress is established using any two design parameters. Results show that “d”, “w”,
“t_epo”, “sy_glue” and “sy_al” will have great influence on passivation cracking while “t_Teos” have
a little impact.
Effect of Heat Treatment Temperature on the Fracture Characteristics of Carbon/Carbon Composite Discs
Authors: Fan Min Xia , Li He Jun , Yuan Yi Dong , Li Ke Zhi
Published: March 2009

Tensile properties and fracture morphologies of C/C composites used as aircraft brake disc at different heat treatment temperature have been studied. Fracture morphologies characteristics of tensile sample were observed with scanning electron microscope (SEM), and fracture mechanism was analyzed. The test results show that, with increase of heat treatment temperature, tensile strength of C/C composites has a descend trend, whereas, breaking strain has an upward trend, and failure mode changes from brittle fracture into “pseudo-plasticity” fracture. Destructional form includes interface debonding, extraction, break and matrix damage and so on, among which interfacial failure is principal fracture mechanism.
Vibration-Based Damage Detection of Composite Wingbox Structures Using Improved Hilbert-Huang Transform
Authors: Chen Huan Guo , Yan Yun Ju , Jiang Jie Sheng
Published: March 2009

A vibration-based approach to detect crack damage in a cantilever composite wingbox is
studied using the improved Hilbert-Huang Transform (HHT). The improved HHT is composed of
HHT with Wavelet Packet Transform (WPT) and a simple but effective method for intrinsic mode
function (IMF) selection. For different damage status, in order to obtain structural dynamic responses,
which imply plentiful damage information, the composite wing boxes were excited by a contrived
square wave signal. Then, the dynamic responses of intact wingbox and damaged wingbox are
disposed using improved HHT. Finally, a feature index vector of structural damage, i.e. the ariation
quantity of instantaneous energy, is constructed. The obtained results show that the proposed damage
feature index vector is more sensitive to small damage than those in traditional signal processing.
Maintenance Scheduling in Risk Assessment Procedures
Authors: Soprano Alessandro , Caputo Francesco
Published: March 2009

The probabilistic analysis of evolutive states of damage, as those induced by fatigue
loads, has been the subject of a wide spectrum of researches in the most recent years, in order to
widen the range of applications and to deal with large structures, especially in the aeronautical field,
where the high safety requirements need the evaluation of very small probabilities of failure.
However, the problem of maintenance policies and scheduling, together with the probabilistic
behaviour of NDT, are difficult to introduce in risk assessment procedures, and are usually referred
as if coming from the particular experience of the different authors, even if they constitute an
essential part of damage tolerance techniques. In the present work the authors summarize the
capabilities of an house-made code which is able to perform the risk assessment of aeronautical
components of sheet type and the experiences obtained when introducing maintenance models, in
order to begin to compare different scheduling techniques.
Research on Fatigue S-N Curves of Corrosion-Damaged Reinforcement
Authors: Tang Hong Wei , Li Shi Bin , Xie Dong Hai , Zhu Cimian
Published: March 2009

Three corrosion degrees of reinforcement are chosen in this paper, which are considered
to simulate minor, medium and severe degrees of corrosion in this field. A reinforcement mass loss
about 5% is used to define a minor degree of corrosion, whereas mass losses about 10% and 20%
are used to define medium and severe degree of corrosion, respectively. Fifteen specimens of the
three corrosion degrees and seven uncorroded specimens are tested under fatigue. According to the
results of the fatigue tests, using stress range as fatigue parameter and 50% as guaranteed
probability, the fatigue S-N curves of the four different corrosion degrees of deformed
reinforcement adaptable for fatigue reliability evaluation are put forward. These curves provide
necessary principle for predicting the residual fatigue lives of aged existing reinforced concrete
bridges.
Synthesis and Characterization of Magnetic Nanoparticles and Their Reinforcement in Polyurethane Film
Authors: Xu Xiao Xue , Zheng Yu Feng
Published: March 2009

Magnetic nanoparticles have attracted intensive attention for their wide applications as biomaterials and magnetic storage materials. Polyurethane is one of the most biocompatible polymers and has been used widely in vivo. In this paper, the magnetite nanoparticles were synthesized by chemical precipitation under different conditions. The as-prepared samples were characterized by X-ray diffraction and transmission electron microscopy, and their magnetic properties were evaluated on a vibrating sample magnetometer. Then the magnetite nanoparticles with different amounts were doped into polyurethane directly and composite films were made. Reinforced by the inorganic particles, PU composite films were also characterized by Fourier transform infrared spectra and mechanical tests., and the surface morphology of the composite film was observed by Atomic Force Microscope The results showed the composite material was reinforced by magnetic nanoparticles and also showed magnetic behavior. This kind of composite materials have the potential to be used as hyperthermia treatment in biomedical field, like coatings on cardiovascular stents.
Mechanical Properties and Fracture Analysis of Mn-Rich Ni-Mn-Ga Polycrystalline Alloys
Authors: Chen Feng , Cai Wei , Zhao Lian Cheng , Zheng Yu Feng
Published: March 2009

In present paper, the mechanical properties and fracturegraphs of Mn-rich polycrystalline alloys are investigated by compression tests and scanning electron microscope (SEM) observations. It is shown that the fracture strength and the rupture strain decrease with the increase of Mn content. It is suggested that the substitution of Mn for Ga reduces the ductility of Ni-Mn-Ga alloys. SEM observations of fracture surface show us typical intergranular crack. There are many little holes and micro-cracks on the grain boundary, which weakens the bond strength of grain boundary causing the intercrystalline cracking.
Numerical Simulation of Fatigue Crack Growth for Curved Cracks Emanating from Fastener Holes in Sheets by the MVCCI Method
Authors: Theilig Holger , Goth M. , Wünsche Michael
Published: March 2009

The paper presents the results of a continued study of curved fatigue crack growth in a
multiple arbitrarily pre-cracked isotropic sheet under plane stress loading. The predictor-corrector
method (PCM) was extended in order to analyse the growth of multiple crack systems in a finite 2D
structure. Together with the recently proposed improved modified virtual crack closure integral
(MVCCI) method we can obtain accurate SIF values also for interacting cracks, and furthermore we
can simulate fatigue crack growth of multiple crack systems in plane sheets under proportional
mixed mode loading conditions. As a result, the program PCCS-2D is written to run within ANSYS
to simulate interacting curved cracks. In order to check the accuracy and efficiency of the proposed
method several example problems are solved. Especially curved cracks emanating from loaded fastener
holes in sheets are analysed.
Evaluation and Test of the Creep-Fatigue Defect Growth in a Cylindrical Structure in a Liquid Metal Reactor
Authors: Park Chang Gyu , Kim Jong Bum , Lee Jae Han
Published: March 2009

This paper deals with the creep-fatigue defect growth behavior at the defect front of a
high temperature cylindrical structure subjected to a cyclic axial tensile loading and a thermal
loading in the LMR(Liquid Metal Reactor) structures. The defect growth evaluation was carried out
per the France RCC-MR A16 guide and UK R5 code and their results were compared. The creepfatigue
structural test to confirm the evaulated results was carried out with a induction heater. The
defect front was investigated at every 100th cycle of a testing by using the metallurgical inspection
technique with an optical microscope. From these results, we showed that the creep-fatigue defect
behavior of a high temperature structure can be predicted with a conservatism by following the
RCC-MR A16 guide and the R5 code.
Accelerated Fatigue Tests of BS 080A42 Steel Using the WBE Mission Loadings
Authors: Abdullah Shahrum , Ariffin Ahmad Kamal
Published: March 2009

This paper describes the laboratory accelerated fatigue tests of BS 080A42 steel using the
shortened variable amplitude (VA) loading produced by the Wavelet Bump Extraction (WBE)
algorithm. In this study, a VA strain loading which was measured on the lower suspension arm of a
vehicle while driven over a pavé road surface was used. The WBE shortened loading was validated
based on the fatigue life comparison to the original loading using four strain-life fatigue damage
models. Experimental fatigue tests were performed using a cylindrical shape specimen with the 6-
mm gauge length smooth surface made from BS 080A42 steel. The experimental findings showed
that the fatigue tests were accelerated from 78.8 hours to 32.5 hours, preserving at least 99% of the
original fatigue damage in the mission loadings. Finally, it is suggested that the WBE algorithm is
suitable for the application of automotive accelerated fatigue tests.
Effects of Stress Frequency and Stress Ratio on the Fatigue of Glass/Epoxy Composite Materials
Authors: Hwang Shun Fa , Su Yi Der
Published: March 2009

Composite materials using polymer resins as matrices have viscoelastic
behavior. This behavior has effects on the fatigue properties of composite materials.
Therefore, one can accelerate the fatigue testing if the loading frequency or
temperature is changed. The purpose of this work is to investigate the accelerated
fatigue properties of glass/fiber composites. In order to establish the accelerated
fatigue properties of glass/epoxy composites, the fatigue testing of unidirectional
specimens with different angles is conducted at room temperature under different
stresses, stress frequencies, and stress ratios. The results indicate that the fatigue life
increases with the increasing of stress frequency or stress ratio for the three types of
unidirectional specimens. The reasons for these increasing effects are also discussed.
Tensile Behavior and Fracture Toughness of Glass Fiber Reinforced Aluminum Laminates According to Fiber Layer Orientation
Authors: Woo Sung Choong
Published: March 2009

The objective of this study is to investigate the tensile behavior and fracture toughness of
glass fiber reinforced aluminum hybrid laminates (GFAL) in association with the fracture process
using plain coupon and single-edge-notched specimens. The tensile properties of GFAL, such as
elastic modulus and ultimate tensile strength, were clearly dependent on the fiber orientations. In
particular, the superiority of GFAL0 in KIC and GIC was much more pronounced than that of
monolithic Al 1050. However, a transverse crack parallel to the fiber orientation reduced the
toughness of GFAL considerably. Microscopic observations of the fracture zone in the vicinity of
the crack tip exhibited various modes of micro-fracture in the respective layers as well as fiber
fractures and interface delamination between fiber composite and Al layers. Such a damage
evolution in GFAL depending on the fiber layer orientation had strongly influence upon the tensile
behavior and the toughness of GFAL.
Failure Analysis and Strength Evaluation in Brazed Joints
Authors: Kang Ki Weon , Shim Hee Jin , Kim C.M. , Kim Jung Kyu
Published: March 2009

The study aimed at the failure analysis and strength evaluation of brazed joints used in
household air conditioner. For these goals, the failure modes were investigated through the
fractographic analysis and micro-Vickers hardness test. The failure modes were classified into two
different types and their mechanism was influenced by heat and internal flaws such as incomplete
penetration and pin holes. Also, a finite element analysis was performed to evaluate the strength
behavior of the brazed joints according to the heat and internal flaws.
Damage Mechanism of Wheel for High Speed Train Based on Fracture Mechanics
Authors: Kwon Seok Jin , Seo Jung Won , Lee Dong Hyung , Lee Chan Woo
Published: March 2009

The majority of catastrophic wheel failures are caused by surface opening fatigue
cracks either in the wheel tread or wheel flange areas. The inclined cracks at railway wheel tread are
initiated and the cracks are caused by wheel damage-spalling after 60,000 km running. Because the
failured railway wheel is reprofiled before regular wheel reprofiling, the maintenance cost for the
railway wheel is increased. Therefore, it is necessary to analyze the mechanism for introduction of
crack. In the present paper, the combined effect on railway wheels of a periodically varying contact
pressure and an intermittent thermal braking loading is investigated. To analyze damage cause for
railway wheels, the measurements for replica of wheel surface and effect of braking application in
field test are carried out. The result shows that the surface cracks in railway wheel tread are due to
combination of thermal loading and ratcheting.
Fatigue Design of Leaf Spring Using Artificial Neural Network
Authors: Jung Won Seok , Bae Dong Ho , Song Gee Wook , Hyun Jung Seob , Kim Bum Shin
Published: March 2009

The vehicle suspension system is directly influenced to ride and handling. Therefore, the
major components of the vehicle suspension system should have enough fatigue strength during its
lifetime to protect passenger from the traffic accident. Spring is one of the major suspension part of
vehicle. Thus, in this paper, a fatigue design method for leaf spring was proposed. At first,
numerical stress analysis for leaf spring assembly was performed. On the base of the analysis results,
fatigue strength of leaf spring was assessed. And next, after studying numerically on geometrical
parameters of leaf spring assembly, an economical prediction method of fatigue design criterion for
leaf spring assembly using the theory of artificial neural network was developed and certified its
usefulness. Without performing a lot of additional fatigue test for a long time, fatigue design
criterion for a new leaf spring assembly having different geometry can be predicted on the base of
the already obtained fatigue data.
Creep Properties of Hastelloy-X Alloy for the High Temperature Gas-Cooled Reactor
Authors: Kim Woo Gon , Yin Sang Nan , Ryu Woo Seog , Chang Jong Hwa
Published: March 2009

The creep properties for the Hastelloy-X alloy which is one of candidate alloys for a high
temperature gas-cooled reactor are presented. The creep data was obtained with different stresses at
950oC, and a number of the creep data was collected through literature surveys. All of the creep data
were combined together to obtain the creep constants and to predict a long-term creep life. In the
Norton’s creep law and the Monkman-Grant relationship, the creep constants, A, n, m, and m’ were
obtained. Creep master curves based on the Larson-Miller parameter were presented for the standard
deviations of 1σ, 2σ and 3σ. Creep life at each temperature was predicted for a longer-time rupture
above 105 hours. Failure probability was also estimated by a statistical process of all the creep rupture
data.
Mechanical Analysis of Buckling Failure of Bedding Rock Slopes
Authors: Liu Cai Hua , Ye Z.H. , Chen Cong Xin , Feng Xia Ting , Shen Q. , Xiao G.F.
Published: March 2009

As a typical model of steep-tilt or moderate-tilt bedding rock slopes, buckling failure
differs greatly from tensile or shear failure. The mechanical characteristic of buckling failure is
analyzed, and the geo-mechanics model of buckling failure is put forward. The process of buckling
failure includes three phases: slope terrane creep deformation, the lower of slope terrane bend
deformation, and terrane structure collapse. Using pressure bar failure theory, a formulation for
calculating critical load of buckling failure is developed, which shows that critical load decreases
with bend length increasing. The relationship between critical slope length and bend length is
analyzed. It is indicated that critical slope length decreases with bend length increasing, and that
critical slope length reaches minimal value while critical load is zero. The minimal slope length can
be considered as a limit value while analyzing buckling failure of bedding slope, and its calculation
equation is developed.
Modeling of Filtration for a Metal Foam Diesel Particulate Filter
Authors: Lee Jeong Min , Sung Nak Won , Cho Gyu Baek , Oh Kwon Oh
Published: March 2009

The filtration of soot in the metal foam DPF has been studied. INCOFOAM®HighTemp is
selected for DPF material for its large specific area for filtration. The structural properties of the
foam such as pore diameter, strut diameter and porosity are determined from the pictures by 3D Xray
scope and SEM. The permeability and Forchheimer coefficient obtained by clean filter
experiments are correlated with the structural properties. During the filtration process, the soot
particles deposited inside the filter affect the local strut diameter, porosity and permeability, which
determine the filtration efficiency and pressure drop. By the analytic model developed, the actual
pressure drop in the engine operation can be predicted.
Microstructure and Damage Evolution of Ceramic Matrix Composite
Authors: Pan Wen Ge , Jiao Gui Qiong , Wang Bo
Published: March 2009

The tensile damage evolution of 2D plain woven C/SiC composites strengthened with 1K
and 3K carbon fiber bundles and microstructure’s influence on material’s damage evolution were
investigated using the Acoustic Emission technology (AE) and failure observation. Experimental
results reveal that damage evolution of these two kinds of composites is a gradual procedure and
this procedure consists of three phases. There is no damage during the first phase. During the
second phase, the damage, mainly consisting of matrix microcrack cracking, interface debonding of
fiber and joining of microcrack, random takes place in the whole area of specimen. During the third
damage phase, the damage, mainly consisting of macrocrack cracking, fibers breaking and fibers
pulling out, mainly takes place in the local failure area of specimen. Because the microstructures of
composites with 1K and 3K carbon fiber bundles are different, their damage mechanisms are
different. Composite strengthened with 1K carbon fiber bundles get in second phase at 90% failure
stress, and their main energy dissipation occurred during the second damage phase. While
Composite strengthened with 3K carbon fiber bundles get in second phase at 80% failure stress, and
their main energy dissipation occurred during the third damage phase.
Effects of Superplasticity in Boronizing of Duplex Stainless Steel
Authors: Hasan Rafidah , Jauhari Iswadi , Ogiyama Hiroyuki , Ramdan Raden Dadan
Published: March 2009

In this research, conventional boronizing process (CB) and a new method of boronizing
process under compression load condition (LB) were conducted and compared in order to study the
effect of superplasticity on boronized substrate. Both processes were conducted on duplex stainless
steel (DSS) with two different microstructures; as-received DSS with coarse grain microstructure
(CDSS); and thermo-mechanically treated DSS with fine grain microstructure (FDSS) which can
show superplastic behavior at high temperatures. Both processes were conducted at duration of 6
hours and temperatures between 1123 and 1223 K. All of boronized specimens demonstrated thin,
smooth and compact morphology of boride layer. For CDSS, both CB and LB processes produced
about similar surface hardness values within the range of 1425 – 2330 HV. For FDSS, CB process
produced surface hardness between 1522 and 2601 HV, while under LB, the highest surface
hardness values in the range of 1659 - 2914 HV were obtained. The result shows that introduction
of load during boronizing has initiated superplastic deformation on FDSS thus accelerated diffusion
of boron atoms into surface which finally lead to significantly higher surface hardness.
The Experiment Study on the Shielded Charge Initiated by the High Speed Fragment
Authors: Huang Jing , Zhang Qing Ming , Li Jin Qing , Xiao Chuan
Published: March 2009

The experiments of the shielded charge initiated by the high speed half- prefabricated
steel fragment has been studied in this paper. The damage way of half- prefabricated steel fragment
to the shielded charge is hit, burning or detonation action. And the damage effect is structure
damage or function damage. The result shows that toward Comp. B explosive with 1.62g/cm3 dense
behind 6mm Q235 steel and of φ 200 mm×100mm size, the fragment’s critical detonation speed is
about 2 400~2 600m/s.
A Study on Sealing Mechanism of Butterfly Valve
Authors: Huh Sunchul , Jung Yong Gil , Park Won Jo , Sim Jae Joon
Published: March 2009

Small Butterfly valve is specially designed for use in industry field and ship. The
important parts of butterfly valve are composed of disk, stem and body. But, like LNG ship, in
enviroment of low temperature, as working condition deteriorates, important of sealing more
increased. In this study, we examine sealing mechanism of butter valve on the base of FEM and
investigate sealing life by measurement. The finite element analysis was carried out to study the
effect of the seal ring shape on bi-directional sealing force of valve. The sealing mechanism was
evaluated by 2-dimensional model in order to save the analysis time. And these analyses used by
material non-linearity and contact element were implemented.
Wear Transitions of Tube-Support Components for a Nuclear Steam Generator under Fretting Conditions
Authors: Jeong Sung Hoon , Park Jung Min , Lee Joong Hui , Lee Young Ze
Published: March 2009

Tubes in nuclear steam generators are held up by supports because the tubes are long and
slender. Fluid flows of high-pressure and high-temperature in the tubes cause oscillating motions
between tubes and supports. This is called as FIV (flow induced vibration), which causes fretting wear
in contact parts of tube-support. The fretting wear of tube-support can threaten the safety of nuclear
power plant. Therefore, a research about the fretting wear characteristics of tube-support is required.
This work is focused on fretting wear transitions from mild wear to severe wear of tube-support
materials by various loads and relative displacements. The transition is defined on the basis of the
changes in wear amount. To investigate the transition, the fretting wear tester was contrived to
prevent the reduction of relative displacement between tube and support by increasing the load. The
tube and support materials were Inconel 690 and 409 SS, respectively. The results show that the
transition of tube-support wear is caused by the changes of the dominant wear mechanism depending
on the applied load and the relative displacement.
Investigation on the Tensile Property of PC/ABS Polymer
Authors: Fang Qin Zhi , Wang Tie Jun , Li Hui Min
Published: March 2009

The tensile property of PC/ABS was investigated with an optical image analysis method
in the paper. With the consideration of polymer micro mechanism, a three-stage phenomenon based
model is used to describe the true stress-strain curves. The regression constants obtained with the
method could be described with definite physical meanings. It is shown that two lateral contractions
are not identical at the later necking stages. The fracture strain could be used as a criterion to
describe uniaxial tensile fracture.
Analysis of Residual Stresses in Multi-Pass Welding Using Element Generation Technique
Authors: Lee Jang Hyun , Lee Kyung Ho , Lee Chan Woo
Published: March 2009

A finite element procedure to predict residual stresses on the multi-pass arc welding
considering the multi-layered beads and solid–liquid phase transformation in the melted bead is
implemented and experimentally validated. The nonlinearities of material properties are considered
in the thermo-elasto-plastic distortion analysis. Element birth and death technique is used to
simulate the weld metal added to base metal in both heat transfer and thermo-elasto-plastic analysis.
Residual stresses and strains are computed for butt welding and T-joints fillet welding. The stress
distributions calculated by proposed finite element analysis procedure are compared with the
measured values of experiments and data available in the other studies. The efficiency of the
proposed finite element analysis and experimental procedure is discussed and demonstrated.
A Study on the Development of Reflective Photoelastic Experimental Hybrid Method on the Static Plane Problems of Isotropic Material
Authors: Hawong Jai Sug , Shin Dong Chul
Published: March 2009

The reflective photoelastic experiment can be used more effectively than the transparent
of photoelastic experimental method in industrial fields. Therefore the reflective photoelastic
experimental hybrid method for the fracture mechanics of isotropic material was developed in this
research. Using the reflective photoelastic experimental hybrid method we can obtain stress
intensity factors and separate stress components from only the isochromatic fringe patterns. The
errors between the experimental values and theoretical values for stress intensity factors are less
than 10%. It was verified that the reflective photoelastic experimental hybrid method is very useful
for the static plane fracture problems, for the stress intensity factors and for the stress components at
the vicinity of the crack-tip in isotropic materials.
MEMS-Based Fabrication of Multi-Walled Carbon Nanotube pH Sensor
Authors: Lee Kyong Soo , Kwon Jea Hong , Moon Seung Il , Cho Woo Sung , Lee Yun Hi , Ju Byeong Kwon
Published: March 2009

In this paper, We presents experimental results that demonstrate the pH sensing
capability of MW-CNTs. High-density, well-aligned carbon nanotubes, which are MW-CNTs and
vertically aligned on a large area of substrate, has been synthesized. The absorption of different
range of pH buffer solution in the MW-CNTs changes the conductivity of the MW-CNTs at room
temperature. A MEMS-based fabrication process was developed to fabricate a device where MWCNTs
based sensing material was precisely assembled pattern.
Robust Electro-Active Paper Actuator in Room Humidity
Authors: Kim Jae Hwan , Wang Nian Gui , Chen Yi , Lee Sun Kon , Yang Chul Ho
Published: March 2009

Electro-Active Paper (EAPap) is attractive for a biomimetic actuator material due to its
merits in terms of lightweight, dry condition, large displacement output, low actuation voltage and
biodegradability. However, the performance of EAPap actuator is so sensitive to humidity that high
humidity is required. We report a robust EAPap actuator that can be activated in room humidity
condition. The EAPap is made by dissolving cellulose fibers into a solution using DMAc solvents,
and made into a sheet by using casting. Thin electrodes are deposited on the cellulose paper to
comprise an EAPap actuator. The fabrication process and the performance evaluation of EAPap are
presented in terms of free displacement with respect to frequency and actuation voltage.
Deformation Measurement by a Digital Image Correlation Method Combined with a Hybrid Genetic Algorithm
Authors: He Rong Song , Horn Chih Ted , Wang Hou Jiun , Hwang Shun Fa
Published: March 2009

Digital image correlation (DIC) is a whole-field and non-contact strain
measuring method. It could provide deformation information of a specimen by
processing two digital images that are captured before and after the deformation. In
this work, 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 corresponding subset after deformation. To invest the accuracy
and reliability of this method, some key parameters are considered. The results
indicate that the out-of-plane shift should be included, and a subset with 30x30 pixels
should be recommended. The population size of 500, 100 generations, and 60
iterations are good enough. As for the searching strategy, it is recommended that the
design variables are divided into three groups, each time only one group is under
search, and they takes terms consecutively.
A DoD Injector Applicable to High-Viscosity Materials in High-Temperature
Authors: Lee Taik Min , Kang Tae Goo , Yang Jeong Soon , Kim Dong Soo , Jo Jeong Dai , Choi Byung Oh , Kim Kwang Young
Published: March 2009

This paper presents the design, fabrication, and performance test of a gap adjustable
piezoelectrically-actuated DoD(drop-on-demand) molten metal injector for application to the 3D
microstructure manufacturing or printed electronics. In the design process, we propose the gap
adjustable mechanism of the piezoelectrically-actuated inkjet system to control the volume and
velocity of the ejected molten metal droplets. In the experimental process, we fabricate the DoD
metal injector and measure the volumes and velocities of the ejected droplets for molten metal as
well as pure water to compare the ejecting performance for the different viscosity of ink and the
operating temperature of the system.
Position Controller for Piezoelectric Actuator
Authors: Yun So Nam , Ham Young Bog , Park Jung Ho , Choi Byung Oh
Published: March 2009

This paper presents a computer-based tracking control approach for a piezoelectric
actuator based on incorporating a feedforward loop with a PID feedback controller. The purpose of
this paper is to improve the hysteresis characteristics of a stack type piezoelectric actuator using the
hysteresis nonlinearity compensator. The system proposed in this study prints by spraying the
molten metal, and consists of a nozzle, heating furnace, operating actuator, and an XYZ 3-axis stage.
As an operating system, the piezoelectric(PZT) method has very valuable uses. The PZT actuator,
however, has a hysteresis nonlinearity due to the ferroelectric characteristics of the PZT element.
This causes problems in the system position control characteristics and deteriorates the performance
of the system. This study proposed a inverse hysteresis model, a mathematic modeling method that
can express the geometric relationship between voltage and displacement, in order to reduce the
hysteresis of the PZT actuator. In addition, system identification and PID control methods were
examined. Also, it was confirmed that the proposed control strategy gives good tracking
performance.
Experimental Investigation of Smart Hull Structures Based on Macro Fiber Composite Actuators
Authors: Sohn Jung Woo , Kim Heung Soo , Choi Seung Bok , Kim Kyung Su
Published: March 2009

In the present paper, the dynamic characteristics of smart hull structure are investigated
for the feasibility of Macro Fiber Composite (MFC) actuator in active vibration control of smart
hull structure. MFC is an advanced anisotropic piezoceramic actuator. Finite element technique was
used to ensure application to practical geometry and boundary conditions of smart hull structure.
Using finite element method, modal analysis and strain distribution were first conducted to
investigate dynamic characteristics of smart hull structure. Based on numerical modal analysis, the
locations of MFC actuators are determined to achieve maximum control authority. Then, the MFC
actuators are attached to the hull structure and natural frequencies and damping coefficients are
identified through experimental modal test.
Noise Effect on Estimation Accuracy of Delamination Monitoring Methods for CFRP Laminate Using Electric Property Change
Authors: Ueda Masahito , Todoroki Akira
Published: March 2009

CFRP laminate can be used itself as a sensor for detecting own damage. The authors have
introduced electric resistance change method and asymmetrical dual charge electric potential
change method to detect a delamination in the CFRP laminate. Although the methods showed good
performance of estimation analytically and experimentally, those are sensitive to electromagnetic
noise. Experimental error caused by such noise in the actual use may affect the accuracy of
estimation. In this paper, influence of the noise on accuracy of estimation was investigated
quantitatively using finite element analysis. It was clarified that the methods have different
characteristics for experimental noise.
Performance Evaluation of the Embedded System for Automated Manual Transmissions Using Test Rig
Authors: Han Ki Won , Ryu Wan Sik , Jeon Jae Wook , Choi Hyeon Ki , Kim Hyun Soo , Hwang Sung Ho
Published: March 2009

Drivers are becoming more fatigued and uncomfortable as traffic densities increase, and
so, can show slower reaction time. They then face the danger of traffic accidents due to their
inability to cope with frequent shifting. To reduce this risk, some drivers prefer automatic
transmissions to manual transmissions. However, automatic transmission requires both higher fuel
consumptions and costs. For this reason, attention to automated manual transmission that can
provide high efficiency, low cost and easy manufacturability has been increasing. In addition, the
function and performance of the electronic control unit of automobiles has improved continually
and rapidly with the growing electronics technology. The ECU is a representative embedded system
in automobiles, which has to satisfy high performance and reliability under the constraints of size
and cost. In this paper, the embedded system platform for automobiles is developed on the basis of
MPC565, and a test rig is developed to perform the basic function test for automatic clutch
actuation. The developed embedded system and clutch control algorithm are validated by the
experimental results performed on the test rig.
Sensor Characteristics of Carbon Fiber Mat
Authors: Zhang Xiao Yu , Li Zhuo Qiu , Song Xian Hui , Lv Yong
Published: March 2009

Structural health monitoring (SHM) is becoming a popular topic. Carbon fiber reinforced
concrete (CFRC) is an intrinsically smart material that can sense strain. The resistivity increases
reversibly under tension and decreases under compression. A new skin-like sensor —cement-based
smart layer had been put forward, which can serve as whole field strain sensor. The smart layer is
satisfactorily consistent with concrete structure. The smart layer is a thin carbon fiber mat cementbased
composite material layer with finite electrodes. It can cover the surface of concrete structure,
and provide on-line reliable information about the deformation of whole concrete structure. The
static characteristics of the new-type sensor had been researched. Its gage factor is 20-25 under
tension and 25-30 under compression within the elastic deformation range. Furthermore the smart
layer has satisfactory linearity and repeatability. In this paper, the sensor characteristics of the bare
carbon fiber mat have been reached. The resistivity of carbon fiber mat has good agreement with
strain under uniaxial tension. The gage factor can be up to 375, and the sensor limit can be up to
10000 microstrain. The strain and the fractional change in electrical resistance .R/R0 are totally
reversible and reproducible under cyclic loading and amplitude-variable cyclic tensile loading.
Optimum Design for Bow Structure of High Tensile Steel Yacht
Authors: Kim Yun Young , Shin Sung Chul , Ko Jae Yong
Published: March 2009

The optimum design for a bow structure of high tensile steel yacht belongs to the
nonlinear constrained optimization problem. The determination of scantling for the bow structure is
a very crucial matter out of whole structural design process of a yacht. This determination may be a
process of satisfying a lot of complicated design constraints empirically, rather than optimizing
some objective function. However, in order to realize optimum or rational design for bow structure
with complicated design constraints, it is necessary to model the design problem as strictly as
possible and to accomplish more highly numerical optimization. Real-coded Micro-Genetic
Algorithm is proposed to find the optimum scantling for the bow structure of high tensile steel yacht
without handling any of penalty functions.
Digital Image Correlation Study on Micro-Crystal of Poly-Crystal Aluminum Specimen under Tensile Load through SEM
Authors: Guo Zhi Qiang , Xie Hui Min , Liu Bao Chen , Pan Bing , Chen Peng Wan , Zhang Qing Ming , Huang Feng Lei
Published: March 2009

In this study, the digital image correlation method(with Newton-Raphson iteration
method) is used to measure the in-plane deformation of poly-crystal aluminum. When the specimen
is exerted a tensile load, the strain distribution of the specimen surface will be inhomogeneous. The
micro-deformation of the poly-crystal aluminum is studied under a SEM(scanning electron
microscope), a series of images of the micro crystal are captured during the loading process. By
using digital image correlation to analyze the images, the displacement and strain of a micro-crystal
are obtained, which provide important data for further analysis of the inhomogeneous properties of
the poly-crystal aluminum.
Impact Analysis and Test of the Spacer Grid Assembly for PWRs
Authors: Song Kee Nam , Yoon Kyung Ho , Lee Jae Jun , Park Kyung Jin
Published: March 2009

The spacer grid assembly, which is an interconnected array of slotted grid straps and
welded at the intersections to form an egg crate structure, is one of the main structural components
of the nuclear fuel assembly of a Pressurized light Water Reactor (PWR). The spacer grid assembly
supports and aligns the fuel rods, guides the fuel assemblies past each other during handling and, if
needed, sustains lateral seismic loads. The ability of the spacer grid assembly to resist the lateral
loads is usually characterized in terms of its dynamic and static crush strengths, which are acquired
from tests. In this study, dynamic buckling tests and finite element analyses on spacer grid assembly
specimens are carried out. Comparisons show that the analysis results are in good agreement with
the test results to within an 8 % difference range. Therefore, we could predict the crush strength of a
spacer grid assembly in advance before performing the dynamic buckling test.
Experimental Study on Dynamic Compression of Nylon Reinforced Concrete
Authors: Zhang Qing Ming , Gu Zhong Ming , Chen Li , Wang Xiao Ying , Hu Shi Sheng
Published: March 2009

Results of tests using two kinds of nylon reinforced concrete samples are described . In
order to deal with the heterogeneous effects of samples resulted from large particles which range
from7mm to10mm in diameters, a SPH bar which is 74mm in diameter is used. There seems
something new and difficult in the method of testing the concrete’s dynamic compressive responses.
The results show that there are obvious strain rate effects in both the two kinds of samples , and the
failure strength increases with the increasing of the strain rate.
Driving Sound Noise Characteristics Emitted by Various Optical Disk Drives
Authors: Oh Se Won , Kim Dong Hyun
Published: March 2009

Optical disk drive (ODD) technology has been rapidly improved to treat the gradually
increasing data storage and data transfer rate. The rotational velocity of the disk must be increased
to deal with huge data. However the increased rotational velocity can inherently cause unwanted
phenomena such as noise and vibration. The major noise sources of the ODD system are
mechanical vibration which generated inside ODD and turbulent aerodynamic noise which
generated by the viscous flow rotation. In this study, practical experimental tests of driving noise
for various optical disk drives have been performed using 1/2” microphone noise measurement
system. Sound insulation case with absorbing materials for the present experimental tests is
designed and constructed in order to minimize the effects of disturbance. Several commercial ODD
models by different manufacturers are practically considered in the present experiments and
compared for realistic driving conditions. It is shown that sound noise level, average data transfer
rate and operating RPM seems to be somewhat different for the ODD models with same proposed
speed by different manufacturers. Moreover, driving sound noise level can be largely affected by
both tray shape and driving speed even for the same apparent data transfer rate.
Analysis of Dual Mass Flywheel Using Discrete Arcspring Model
Authors: Kim Tae Hyun , Song Han Lim , Hwang Sung Ho , Kim Hyun Soo
Published: March 2009

This paper presents a discrete analysis approach to investigate performance of the DMF.
An arcspring installed between the flywheels is modeled as n - discrete elements. Each element
consists of mass, spring and nonlinear friction element. The nonlinear friction model is proposed to
describe Stribeck effect and viscous friction depending on the relative sliding velocity. The DMF
performance such as hysterisis characteristics are investigated by comparing the experimental
result. In addition, the torque characteristics transmitted to the driveshaft are evaluated by
comparing the test result from manual transmission bench tester. It is found that discrete DMF
model described the automotive driveline behavior closely. It is also found that the friction
characteristics of the arcspring depends on the relative sliding velocity between the friction
surfaces, which varies depending on the relative position of the DMF arcspring.
A Study on the Vibrational Characteristics of the Continuous Circular Cylindrical Shell with the Multiple Supports Using the Experimental Modal Analysis
Authors: Lee Young Shin , Kim Hyun Soo , Han C.H.
Published: March 2009

An experimental modal analysis is the process to identify structure's dynamic
characteristics. For investigating vibrational characteristics of cylindrical shell with multiple
supports, modal testing is performed using impact exciting method. The frequency response
function(FRF) measurements are also made on the experimental model within the frequency range
from 0 to 4kHz. Modal parameters are identified from resonant peaks in the FRF’s and animated
deformation patterns associated with each of the resonances are shown on a computer screen. The
experimental results are compared with analytical and FEA results.
Nonplanar Nonlinear Vibration Phenomenon on the One to One Internal Resonance of the Circular Cantilever Beam
Authors: Kim Myoung Gu , Cho Chong Du , Kim Chang Boo , Cho Ho Joon
Published: March 2009

Experimental and theoretical study of the non-planar response motions of a circular
cantilever beam subject to base harmonic excitation has been presented in this paper work.
Theoretical research is conducted using two non-linear coupled integral-differential equations of
motion. These equations contain cubic linearities due do curvature term and inertial term. A
combination of the Galerkin procedure and the method of multiple scales are used to construct a
first-order uniform expansion for the case of one-to-one resonance. The results show that the nonlinear
geometric terms are very important for the low-frequency modes of the first and second
mode. The non-linear inertia terms are also important for the high-frequency modes. We present the
quantitative and qualitative results for non-planar motions of the dynamic behavior.
Study on Formative Mechanism of Blasting Crater in Reinforced Concrete under Internal Blast Loading
Authors: Fu Yue Sheng , Zhang Qing Ming , Wang Han Jun
Published: March 2009

The variation process of radius and pressure of explosion products in borehole are
analyzed in this paper, based on theory of damage and structural mechanics, the formative
mechanism of blasting crater in reinforced concrete under internal blast loading is analyzed, the
computation method of crater size has been proposed. The calculated results are identical with
experimental results on the whole.