bluuebunny/crossref_metadata_2025 huggingface dataset:
Flexural Fatigue Damage Evolution for Partially High Percentage Fiber Reinforced Concrete
Authors: Yi Cheng , Shen Shi Zhao , Xie He Ping , Wang Chang Jun
Published: March 2009

Partially High Percentage Fiber Reinforced Concrete (PHPFRC) is a kind of cement
composite in which fibers are concentrated with high volume fraction in the tension region of the
component under bending. Therefore, PHPFRC possesses much higher load bearing capacity,
rigidity, fatigue and fracture properties than conventional steel fiber reinforced concrete (SFRC)
while its cost is similar to that of SFRC. In this paper, the fatigue test of PHPFRC is carried out to gain
its flexural fatigue damage evolution rule. It is found from the test that, PHPFRC have long
post-crack fatigue life and its fatigue damage is tough damage. Based on the continuum damage
mechanics and fatigue behavior of the specimens, a fatigue damage variable D for PHPFRC is
defined and the elementary form of damage evolution function is determined. For the specimens in
which average fiber volume fraction are 1.2% and local fiber volume fraction are 10%, the function
parameters and the damage threshold value are given according to the test results.
Numerical Study of the Fatigue Crack in Welded Beam-To-Column Connection Using Cohesive Zone Model
Authors: Lequesne Cedric , Plumier A. , Degee H. , Habraken Anne Marie
Published: March 2009

The fatigue behaviour of the welded beam-to-column connections of steel moment resisting frame in seismic area must be evaluated. The cohesive zone model is an efficient solution to study such connections by finite elements. It respects the energetic conservation and avoids numerical issues. A three-dimensional cohesive zone model element has been implemented in the home made finite element code Lagamine [1]. It is coupled with the fatigue continuum damage model of Lemaître and Chaboche [2]. The cohesive parameters are identified by the inverse method applied on a three points bending test modelling.
Modelling Intergranular Microfracture Using a Boundary Cohesive Grain Element Formulation
Authors: Sfantos G.K. , Aliabadi M.H.
Published: March 2009

In this paper, intergranular microfracture evolution in polycrystalline brittle materials is simulated using a cohesive grain boundary integral formulation. A linear cohesive law is used for modelling multiple microcracking initiation and propagation under mixed mode failure conditions, encountering the stochastic e=ects of the grain location, morphology and orientation. Furthermore, in cases where crack surfaces come into contact, slide or separate, fully frictional contact analysis is performed.
Feasibility and Application on Ultrasonic-Polarized Shear Wave of Fiber Orientation Detection in Orthotropic Composite Laminates
Authors: Park Je Woong , Im Kwang Hee , Hsu David K. , Kim Sun Kyu , Yang In Young
Published: March 2009

It is very important to detect fiber orientation error in orthotropic composite laminates
because the layup of a CFRP (carbon-fiber reinforced plastics) composite laminates affects the
properties of the laminate, including stiffness, strength and thermal behavior. In this study, an
investigation of shear wave ultrasonic technique was carried out in order to detect stacking
orientation error for the orthotropic composite laminates. During testing, the most significant
problem is that the couplant conditions do not remain the same because of changing the viscosity
of the couplant. Therefore, the design and use of a shear wave transducers would greatly aid in
alleviating the couplant problem. A pyramid with an isosceles triangle with two 45o was made of
aluminum to generate shear waves using two longitudinal transducers based on ultrasonicpolarized
mechanism. Also, the signal splitter was connected to the pulser jack on the
pulser/receiver and to the longitudinal transducers which were mounted with mineral oil. The shear
transducer was mounted on the bottom as a receiver with burnt honey. It is found that the shear
wave was generated at a maximum and a minimum based on the ultrasonic-polarized mechanism.
Finally, test results with model data were compared for a fiber orientation of the laminates.
Simulation of Fatigue Crack Growth Under Random Overloads with Retardation
Authors: Zou Xiao Li , Yang Jian Hui
Published: March 2009

In order to study the behavior of fatigue crack propagation under random overloads, a
Monte Carlo simulation scheme is proposed. Overloads of Poisson flow with uniform distribution
on base-line constant-amplitude cyclic loads are considered. The retardation effect of overload is
taken into account using crack closure model and the crack opening stress level is assumed to vary
linearly in the yield zone produced by the overload. The fatigue crack growth curve from initial
crack size till fatigue failure is simulated step by step. Through the large number of the simulated
samples, the average fatigue crack propagation life is calculated. Finally, the influence of overload
intensity and magnitude on fatigue crack propagation life is studied.
Factors Affecting the Low Cycle Fatigue Behavior around the Weak Axis of Welded I-Section Bracing Members
Authors: Zhang Yao Chun , Lian Wei An , Zhang Wen Yuan
Published: March 2009

The low cycle fatigue behavior and energy dissipation capacity around the weak axis of the welded I-section bracing members are investigated by 35 pinned-pinned bracing specimen tests under the axial cyclic loading with different characteristics. Particular attention is paid to the effects of loading amplitude, loading history and geometry properties of these members. It is found that the fatigue damage propagating to fracture in the flanges of the bracing members can be divided into 3 stages involving the macroscopic surface crack initiation, the penetrated crack formation and the penetrated crack propagation. Some empirical formulas to estimate the fatigue life and cyclic energy dissipation capacity of the bracing members are also presented based on the experimental data. The statistical analysis indicates that the fatigue life to surface crack initiation significantly depends on the inelastic local buckling and will increase with decreasing width-thickness ratio of the flanges and increasing slenderness ratios of the bracing members. Besides, it is found that the low cycle fatigue and energy dissipation of these members also depends on loading amplitude and loading history, and the effects of overloads and mean compression amplitude can improve the fatigue performance of bracing members. The test results show that the bracing members with better low-cycle fatigue resistance have the better energy dissipation capacities.
Fatigue Life Simulation of a High Pressure Breech System
Authors: Koh Seung Kee , Na Eui Gyun , Baek Tae Hyun , Kang K.J. , Ahn S.T. , Han T.H.
Published: March 2009

In order to evaluate the structural integrity of the breech system used for a thick-walled
cylinder subjected to pulsating high internal pressure, fatigue life simulation of a breech system was
performed. A stress analysis of the breech was performed to locate the critical region vulnerable to
crack initiation. Low-cycle fatigue behavior of the breech material was investigated to obtain the
fatigue crack initiation properties. Elastic-plastic finite element stress analysis resulted in a stress
concentration at the breech ring groove root. Strains at the breech ring and block were
experimentally measured using strain gages and resulted in similar values compared to the
calculated strains. Local strain approach was employed to estimate the fatigue life of the breech
system for crack initiation at the groove root of the breech ring. Fatigue tests using simulation
specimens were performed and an averaged fatigue life was obtained, showing a very good
agreement with the calculated fatigue life within a factor of two.
An Experimental Study on the Pre-Strain Effect of API 5L X65 Pipeline for Natural Gas Transmission
Authors: Baek Jong Hyun , Kim Young Pyo , Kim Woo Sik , Seok Chang Sung
Published: March 2009

Pipelines for natural gas transmission may be subjected to plastic deformation by the
outside force such as ground subsidence, ground liquefaction, cold bending and mechanical
damage. Plastic deformation affects the tensile properties and fracture toughness. Tensile test,
Crack tip opening displacement test and Charpy impact test were conducted on an API 5L X65 pipe
to investigate the mechanical properties of pipeline subjected to plastic deformation. Axial tensile
pre-strain up to approximately 10% was applied to plate-type tensile specimens cut from the API 5L
X65 pipe prior to mechanical testing. Tensile test revealed that the yield strength and the tensile
strength increased with increasing tensile pre-strain. However, the CTOD and Charpy impact
energy values for crack initiation decreased with increasing tensile pre-strain.
Modification of the Curing Characteristics of the Photocurable Resin FA1260T for 3D Microfabrication Using Microstereolithography
Authors: Kim Sung Hoon , Jung Dae Jun , Joo Jae Young , Jeong Sung Ho
Published: March 2009

The curing characteristics of a photocurable resin are critical factors that often decide the
ultimate resolution and structural sharpness of a final product fabricated by microstereolithography
(μ-STL). In this study, we investigated the curing characteristics of the FA1260T photopolymer
under a visible laser light of 442nm wavelength. Modification of the curing property of the
FA1260T is attempted to reduce the cure depth (Dc) by adding a radical quencher to the resin. Also,
an organic solvent was used to reduce the resin viscosity for an improvement of the flatness of the
liquid surface during layer-by-layer curing. As a result, the minimum Dc has been reduced over a
factor of 3 with no abrupt increase. Samples of three dimensional microstructures fabricated using
the modified FA1260T are presented.
Observations of Fatigue Damage in the Press-Fitted Shaft under Bending Loads
Authors: Lee Dong Hyung , Kwon Seok Jin , Choi Jae Boong , Kim Young Jin
Published: March 2009

In this paper, the characterization of fretting damage on press-fitted specimens is
proposed by experimental methods. A series of fatigue tests and interrupted fatigue tests on pressfitted
specimens were carried out by using a rotate bending fatigue test machine. Macroscopic and
microscopic characteristics were observed to identify fretting damage mechanism with a scanning
electron microscope (SEM) and profilometer. The mechanism of fretting fatigue damage on pressfitted
structure is discussed from experimental results. It is found that small cracks of 30~40m in
depth are initiated when the specimen reached about 10% of the total life, and thus almost 90% of
the fretting fatigue life of press fits can be considered to be in the crack propagation phase. Most of
fatigue cracks are initiated at 1050m inner side of contact edge, and multiple cracks are
nucleated and interconnected in the fretted surface. The crack nucleation angle in the near contact
edge region is larger than that in the inside of the contact edge region. The fretting wear increased
with increasing fatigue cycle. Since the fretting wear is relevant to the evolution of surface profile,
the fretting fatigue is observed to be closely related with the fretting wear.
An Experimental Study of Automotive Bushing for Radial Mode
Authors: Jeong Jae Young , Park Jong Sik , Kim Sung Jin , Lee Su Young , Lee Woo Hyun , Park Chan Seok , Hong Jang Pyo , Lee Seong Beom
Published: March 2009

An automotive bushing is a device used in automotive suspension systems to reduce the
load transmitted from the wheel to the frame of the vehicle. A bushing is a hollow cylinder, which
is bonded to a solid steel shaft at its inner surface and a steel sleeve at its outer surface. The relation
between the force applied to the shaft and the relative deformation of a bushing is nonlinear and
exhibits features of viscoelasticity. In this paper, an automotive bushing is regarded as nonlinear
viscoelastic incompressible material. Instron 8801 equipment was used for experimental research
and ramp-to-constant displacement control test was used for data acquisition. Displacementdependent
force relaxation function was obtained from the force extrapolation method and
expressed as the explicit combination of time and displacement. Pipkin-Rogers model, which is the
direct relation of force and displacement, was obtained and comparison studies between the
experimental results and the Pipkin-Rogers results were carried out.
Contact Damage Analysis of Hot Mill Spindle Assembly with Kinematics Simulation
Authors: Byun Seong Woo , Lee Young Shin , Lee Hyun Seung , Lee Je Jun
Published: March 2009

The hot mill spindle assembly is the important component of the hot rolling process and
used for transmission of rotational power. The contact surface between end coupling and slipper
metal have high stress concentration due to operation interference. The life cycles of slipper metal
are reduced by the contact surface damage. In this study, the structural analysis and kinematics
simulation are performed by applying the various driving angle and dynamic boundary condition of
the mill spindle assembly. This study aims to minimize the contact damage which might happen in
the production process.
Effect of the Frequency of the Cyclic Load to the Inverse Analyses of the Heat Conduction in Infrared Thermography
Authors: Machida Kenji , Miyagawa Shohei
Published: March 2009

Influence of the frequency to the temperature image obtained by an infrared
thermography was investigated using specimens of three kinds of materials at four kinds of
frequencies of the cyclic load. Then, the infrared hybrid method was developed to separate
individual stress components. However, the influence of heat conduction is inevitable in the infrared
stress measurement method. Therefore, an error arises in the infrared hybrid analysis. Then, the
system which corrects the error by the inverse analysis was developed. Thereby, the accuracy of the
stress intensity factor was able to be raised. Furthermore, the accuracy of hybrid method
considering to heat conduction was discussed in comparison with the 3-D finite element analysis
and 2-D hybrid method.
Investigation of Local Failure Criteria of Wall-Thinned Area by Simulated Specimen Tests
Authors: Kim Do Hyung , Kim Jin Won , Na Yeon Soo , Park Chi Yong
Published: March 2009

The objective of this study is to develop a local failure criterion at wall-thinning defect of
piping components. For this purpose, a series of tensile tests was performed using several types of
specimens with different stress state under tension, including smooth bars, notched round bars and
grooved plates. In addition, finite element (FE) simulations were performed for all tests, and its
results were compared to the test results. From the comparisons, the equivalent stress and strain
corresponding to maximum load and final failure of the notched round bar specimens were
proposed as the local failure criterion which is a function of stress triaxiality at notched area. The
criteria were verified by employing them to the estimation of maximum load and final failure of
grooved plate specimen tests.
Evaluation of Thermal Fatigue Properties of Surface Treated AISI H13 Steel for Aluminum Die-Casting
Authors: Youn Kuk Tae , Rhyim Young Mok , Yang Won Jon , Lee Jong Hoon , Lee Chan Gyu
Published: March 2009

The influence of surface treatment such as nitriding, TNHT(Ti Nano Heat-treatment,
PHILOS TECHNOLOGIES, INC.) and PVD coating on the thermal crack propagation behavior of
hot work die steel was investigated. To examine the thermal fatigue resistance, the cyclic thermal
shock system consisted of induction heating and water spray quenching unit was constructed and
Lm is proposed as the index representing the susceptibility to crack initiation and propagation.
Thermal stress depending on test temperature was also simulated by FEM. The TNHT specimen
showed lower Lm value than as-heat treated specimen but, in the case of maximum and average
crack length, the TNHT specimen exhibited higher value than those of as-heat treated specimen.
This means that the small number of large cracks were initiated and propagated selectively in the
TNHT specimen. This result can be caused by two contrary effects of diffusion layer, those are
introduction of the residual compressive stress good for mitigation of thermal tensile stress and very
high surface hardness harmful for crack initiation. However, Lm value of salt-bath nitriding
specimen was very high due to the white layer in spite of the existence of diffusion layer.
Development of a Reconfigurable Mobile Robot and Precise Position Estimation Based on Extended Kalman Filter
Authors: Yeo Gee Hwan , Kim Jung , Kang Bong Soo
Published: March 2009

This paper presents design concepts of a reconfiguration mobile robot developed in
Hannam University and experimental results of position estimation by multiple sensors. In order to
achieve high reliability and mobility in maneuver, driving motors of the mobile robot are assembled
inside the wheels of the mobile robot, and the rhombus-shaped structure of the mobile robot with
four wheels yields as good adaptability to rough terrain as a six-wheel mobile robot. Since the
proposed mobile robot receives multiple sensor signals from odometers and an orientation sensor,
states related to position and orientation of the mobile robot are optimally calculated by the
extended Kalman filter. Experimental results show that tracking errors of the mobile robot can be
reduced remarkably by the optimal state observer.
Tensile Damage Characterization in Nicalon Fiber Reinforced Ceramic Composites
Authors: Kim Jeong Guk
Published: March 2009

Tensile failure behavior of ceramic matrix composites (CMCs) was characterized with
nondestructive evaluation (NDE) techniques. Prior to the mechanical testing, infrared (IR)
thermography was employed to obtain thermal diffusivity maps for CMC specimens. IR
thermography also was used for quantitative analyses of the progressive damage and in-situ
monitoring of the damage during tensile tests, while ultrasonic (UT) C-scans were used to present
defect distributions of the composites. The thermal diffusivity map showed good consistency with
ultrasonic C-scan results of CMC specimens. In this investigation, qualitative relationship
between UT signatures and thermal diffusivity has been introduced, and the temperature changes of
CMC specimens during tensile test have been measured. Moreover, the correlation between NDE
results and fracture behavior of CMCs has been presented to understand tension fracture behavior of
CMCs.
The Predictions of the Fretting Wear between Supporting Grids and Cladding Tubes of Nuclear Fuel Rod
Authors: Park Young Chang , Kim Yong Hwan , Lee Seung Jae , Lee Young Ze
Published: March 2009

Fretting can be defined as the oscillatory motion with very small amplitudes, which
usually occur between two contacting surfaces. Fretting wear is the removal of material from
contacting surfaces through fretting action. This fretting wear, which occurs between cladding
tubes of nuclear fuel rod and grids, causes in damages the cladding tubes by flow induced
vibration in a nuclear reactor. In this paper the fretting wear tests were performed with two
types of cladding tubes and three types of supporting grids in water. Fretting wear tests were
done using various applied loads. From the results of fretting tests, the wear amounts of tube
materials can be predictable by obtaining the wear coefficient using the work rate model.
Depending on various normal load, tube materials, and supporting grid shapes, distinctively
different wear scar of fretting and stick-slip mechanism can occur.
Root Cause Analysis of Tube Weld Failure of the Lubrication Oil Cooling Tube in Thrust Bearing of Pump
Authors: Boo Myung Hwan , Park Chi Yong
Published: March 2009

Dissimilar weld region located at the cooling tube of pump was damaged and failed.
We performed a root cause analysis using the Scanning Electron Microscopy (SEM) and Energy
Dispersive X-ray Spectroscopy for the fractured surface. Many internal defects were shown in the
fracture section. Root cause analysis shows that the failure is due to welding at higher temperature
over 1000. This was confirmed by high-temperature cracks observed with SEM. In this study
Failure scenario including initial crack generation, propagation of corrosion cracks and final failure,
has been constructed and verified.
Creep-Life Prediction of Type 316LN Stainless Steel by Minimum Commitment Method
Authors: Kim Woo Gon , Yin Song Nan , Ryu Woo Seog , Yi Won
Published: March 2009

This paper presents the results of the Minimum Commitment Method (MCM) applied to
predict the creep rupture life of type 316LN SS. Constant A, and the function of P(T) and G(σ) being
used in the MCM equation were determined. To determine a proper value of the constant A, a focal
point method and a trial and error one were adopted, respectively. It was found to be A=-0.02~-0.05
for type 316LN SS. Each prediction curve with the A values were presented up to 106 hours and
compared to the experimental data at each temperature. Using the short-term creep rupture data for
under 2,000 hours, a long-time rupture reaching up to 106 hours was predicted by the MCM.
A Novel Microcantilever Device with Nano-Interdigitated Electrodes (Nano-IDEs) for Biosensing Applications
Authors: Lee Jung A , Yun Jae Young , Lee Seung Seob , Lee Kwang Cheol
Published: March 2009

We present a novel microcantilever device with nano-interdigitated electrodes (nano-IDEs) and
selective functionalization of nano-IDEs for biosensing applications. The nano-IDEs play a role in
precisely addressing capture molecules to a specific region on a microcantilever. This leads to a
detectable surface stress due to the binding of target molecules. 70~500 nm-wide gold (Au) nano-
IDEs are fabricated on a low-stress SiNx microcantilever with dimensions of 100~600 μm in length,
and 15~60 μm in width, with a 0.5 μm thickness using electron beam lithography and bulk
micromachining. 32~96 nm-thick streptavidin is selectively deposited on one side of nano-IDEs
using cyclic voltammetry at a scan rate of 0.1 V/s with a range of -0.2~0.7 V during 1~5 cycles. The
selective deposition of streptavidin is confirmed by fluorescence microscopy and atomic force
microscopy (AFM).
Large Displacement Out-Of-Plane Bimorph Actuator for Optical Application
Authors: Jeung Won Kyu , Kim Yong Jun , Choi Seog Moon
Published: March 2009

A new thermal bimorph actuator for large out-of-plane displacement is designed,
fabricated and tested. The deflecting beam is composed of polyimide, heater, and polyvinyl
difluorides with tetrafluoroethylene (PVDF-TrFE). The large difference of coefficient of thermal
expansion (CTE) of two polymer layers (polyimide and PVDF-TrFE) can generate a large
deflection with relatively small temperature rising. Compared to the most conventional micro
actuators based on MEMS (micro-electro mechanical system) technology, a large displacement,
over 1 mm at 20 mW, could be achieved. The proposed actuator can find applications where a large
vertical displacement is needed while keeping compact overall device size, such as a micro
zooming lens, micro mirror, micro valve and optical application.
A Development of Miniaturized Piezoelectric Actuator System for Mobile Smart Structures
Authors: Kang In Pil , Chae Hyo Byung , Park Ki Hoon , Yoon Kwang Joon , Xin Li Li , Kang Tae Sam
Published: March 2009

A smart material actuator is required for a smart structure having multifunctional performance.
Among the smart material actuators, piezoelectric actuator is known for its excellent large force generation
in broad bandwidth in a compact size. However it needs relatively large actuation voltage requiring a bulky
hardware system. This study is mainly concerned to develop a self-powered miniaturized piezoelectric
actuator driver (MIPAD) controlled by a radio controller for small sized piezoelectric smart structures. It can
receive command from other microprocessors or a remote radio controller. We designed a real hardware and
it demonstrated good performances even though the driving system was very small. The MIPAD is expected
to minimize the weight and size of the piezoelectric actuator system and it can be easily embedded into
mobile smart structures.
Behavior of Lightweight Piezoceramic Composite Actuator under Compressive Load
Authors: Nguyen Quoc Viet , Goo Nam Seo , Park Hoon Cheol
Published: March 2009

In this work, behavior of a unimorph piezoceramic actuator, LIPCA (Lightweight Piezo-
Composite Actuator) has been numerically and experimentally investigated. By measuring the
lateral displacement created by the compressive load, the buckling load of the LIPCA was
determined. Under simply supported configuration, the measured buckling load agreed well with
the geometrically nonlinear buckling load from the finite element analysis. The measured data
shows that the lateral displacement of the LIPCA is significantly increased when the electric field is
prescribed to the LIPCA in addition to the compressive load. The measured data was compared
with the computed results from the geometrically nonlinear finite element analysis. The numerical
simulation agreed well with the measurement for low compressive load and low electric field.
Research on Liquid Concentration Real-Time Detecting System Based on F-P Interferometer
Authors: Wei Wen Li , Yang Xiu Fang
Published: March 2009

A kind of dynamic tracking system for conducting high accuracy measurement of
transparent liquid concentration is designed by means of line matrix CCD receiving fringes in
accordance with the relations between liquid concentration and refractive index as well as the
relations among refractive index, interference light wavelength of optical fiber F-P interferometer
and grade orders. The detecting system can recognize or detect 0.01% of concentration variations
via measuring a group of alcohol.
One-Dimensional Shape Memory Alloy Model Applicable to Any Status of Stress and Temperature
Authors: Chung Jong Ha , Heo Jin Seok , Won Myoung Sik , Lee Woo Yong , Lee Jung Ju
Published: March 2009

The transformation kinetics formulation is the principal factor underlying the constitutive
model of shape memory alloys. Therefore, the transformation kinetics formulation, which is
applicable to any status of stress and temperature, is essential for predicting the material behavior of
SMAs. In this work, we show that the transformation kinetics of the Brinson model, which is the
most widely used 1-dimensional model, has shortcomings under certain stress and temperature
histories. In addition, we propose a modified transformation kinetics model that can be used for any
stress or temperature conditions. The martensite transformation kinetics is modified so that the
transformation from austenite into temperature-induced martensite, due to the decrement of
temperature, is coupled with a transformation from austenite or temperature-induced martensite into
stress-induced martensite, due to the increment of the stress. Through this modification, the
suggested model can simulate the behavior of shape memory alloy materials under arbitrarily
changed circumstances at every stress-temperature region.
Fabrication of Single Walled-Carbon Nanotubes Based pH Sensor Using Ultra-Precision Spray
Authors: Kwon Jea Hong , Lee Kyong Soo , Ju Byeong Kwon
Published: March 2009

The concentration of the hydroxyl radical is a critical parameter to be measured for
monitoring the condition of aqueous biological species, or for predicting the path of chemical
reactions. This paper describes a novel method for fabricating a very simple and fast response pH
sensor compose of single walled-carbon nanotubes (SW-CNTs) using an ultra-precision spray. Such
CNT-based sensor shows amperometric response in buffer solution at different hydroxyl radical
concentrations and electrical conductance of SW-CNTs depends on the pH value. Our results
suggest that sprayed CNT sensors are potential candidates as biosensors in future large-scale
throughput devices.
Rectangular Microlens Array Having High Sag for Multi Chip LED Packaging
Authors: Jeung Won Kyu , Lim Chang Hyun , Kim Tae Hoon , Choi Seog Moon
Published: March 2009

A novel rectangular shape microlens array having high sag for solid-state lighting
is presented. The rectangular shape of proposed microlens can maximize the fill factor of
silicon based light-emitting-diode (LED) packaging and minimize the optical loss through the
reduction of unnecessary reflection at the same time. Microlens, which has high sag, over 3
75 μm and large diameter, over 3 mm can enormously enhance output optical extraction eff
iciency. Moreover wafer level packaging technology is adopted to improve the aligning accu
racy and mass production of LED packaging. This wafer level microlens array can be direc
tly fabricated on LED packaging using replication method. It has many advantages in optica
l properties, low cost, high aligning accuracy, and mass production.
Impact Modeling of Sawing Tasks and Experimental Verification Using a Parallel Robot
Authors: So Byung Rok , Lee Jae Hoon , Yi Byung Ju , Han Seok Young , Kim Seon Jung
Published: March 2009

The amount of the external impulse exerted on the object being sawn has been treated one of
important control parameters. At the same time, the internal impulses experienced in the joints
should be taken into account to avoid serious damage or injury at the joints of robot. This paper
discusses the impulse models in a straight sawing task. And, a motion planning algorithm is
proposed, which employs the external and internal impulses as performance indices. For this, the
gradient projection method is employed to exploit the kinematic redundancy of the robot structure.
Finally, through both simulation and experimentation for the sawing task, the effectiveness of the
proposed motion planning algorithm could be verified.
Experimental and Numerical Analyses of a Head Arm Assembly of a Micro-Drive
Authors: Shi B.J. , Shu Dong Wei , Luo J. , Ng Q.Y. , Lau J.H.T.
Published: March 2009

Hard disk drives (HDD) are now the most important means of information storage, and
they continue to be made smaller in size, higher in capacity, and lower in cost. The dynamic
performance of an HDD has been an increasingly important consideration for its design, as we
move forward toward its consumer applications. The dynamic properties of the head arm assembly
(HAA) of a micro-drive were investigated using both experimental and numerical techniques. A
finite element model for studying the dynamic property of the HAA was created and modified
according to the experimental results. Good correlation between the experimental results and those
by finite element simulation was achieved.
On Stability and Support Measures of Rock Mass Surrounding the Diphead of a Coal Mine
Authors: Liu Quan Sheng , Hu Yun Hua , Jiao Yu Yong
Published: March 2009

The instability of the roadway is a general problem for most of the deep mine roadways
due to high geo-stress and large deformation, which require that the more reasonable and effective
support measures are designed and employed. By applying the 3-D explicit finite difference
software FLAC3D, this paper establishes the numerical calculation model of a roadway located in
about 700m depth based on the geologic condition of the site which the roadway is in as well as the
results of the in-situ stress measurement and the laboratory tests for the physical-mechanical
properties of rock. Furthermore, three different support scenarios are raised and the optimum one is
determined by calculating and analyzing the distribution of the plastic zone and displacement field
in the rock surrounding the roadway with the above three scenarios.
Development of System for Simultaneous Measurement of Stress and Temperature
Authors: Umezaki Eisaku , Abe Masahito
Published: March 2009

A system was developed for simultaneously measuring stress and temperature in
structures in time series. The stress and temperature were measured using the photoelastic technique
in the form of phase stepping and the thermographic technique, respectively. Four phase-stepped
photoelastic images were captured simultaneously using beam-splitting optics. A beam splitter was
used for transmitting light in the visible range while simultaneously reflecting light in the infrared
range. The system was applied to ultraviolet curing resin with a step part illuminated with
ultraviolet rays, and the stress and temperature in the curing process were measured. Results
showed that the stress and temperature in the curing process can be measured simultaneously in
time series using the system. The step part of the resin affected the distribution of the stress and
temperature
Experimental Study of Reinforced Concrete Subjected to Shock Loading
Authors: Ning Jian Guo , Jiang Fang
Published: March 2009

Split Hopkinson pressure bar (SHPB) and one-stage light gas gun are utilized to study the
dynamic mechanical properties of reinforced concrete (RC) subjected to shock loading. The former
experimental results show that the strength and stiffness of RC decrease but the ductibility increases
with increasing the volume fractions of reinforced fibers due to more damage in the concrete and
interface. For the latter experiment, three stress-time curves are recorded by three manganin
pressure transducers embedded in the targets. With the stress-time records, complete histories of
particle velocity and strain etc. can be obtained at any point within the gauged regions of RC using
the path line principle of Lagrangian analysis method. The stress-strain curves of RC present
stagnant-return properties. And some other dynamic properties can be gained, such as strain rate
hardening, wave shape dispersion effects and the rheological properties of the concrete.
Dynamic Compressive Strength of Aluminum Alloy Foams
Authors: Wang Zhi Hua , Ma Hong Wei , Zhao Long Mao , Yang Gui Tong
Published: March 2009

The dynamic compressive behavior of open-cell aluminum alloy foams with different
length of specimens was investigated using the split Hopkinson pressure bar technique. Plastic
strength was measured for aluminum alloy foam specimens having the three cell sizes but similar
cell microstructure. Longer specimens exhibited lower mean strength and broader scattering of the
strength values than the shorter ones. It can be observed that mechanical response of aluminum
alloy foams appear to be dependent of the cell size for both the shorter and longer specimens.
Analysis of Impact Fracture Behavior in Bulk Amorphous Metals Using Instrumented Impact Testing Apparatus
Authors: Shin Hyung Seop , Kim Ki Hyun
Published: March 2009

In order to investigate the mechanical behavior of newly developed materials such as
bulk amorphous metals, it is essential to use small-size specimens. An instrumented impact testing
apparatus was devised which could provide a load-displacement curve on subsize Charpy
specimens under impact loading without oscillations. The impact fracture behaviors of Zr-based
bulk amorphous metals (BAM) were investigated by using the instrumented impact tester using
both V-notched and precracked subsize Charpy specimens. It was found that most of the fracture
energy absorbed was used in the process of crack initiation through the development of shear bands.
Development of FRP-Concrete Composite Bridge Deck in Korea - State-of-the-Art Review -
Authors: Nam Jeong Hun , Yoon Soon Jong , Moon Hwan Doo , Ok Dong Min , Hong Soon Jung
Published: March 2009

The bridge deck is the most vulnerable element in the bridge system because it is
exposed to direct actions of wheel loading, chemical attacks, and temperature and moisture effects
including freezing and thawing, shrinkage, humidity, etc. In 1980’s, several countries, such as USA,
Japan, and Canada, already realized that the service life of the deck is critical for that of the whole
bridge, and the research was initiated to develop new material and structural system to improve
deck behavior. In recent years, it has been encouraged to develop more durable, easily constructible,
and more cost effective bridge deck than the current one in Korea. In this study, a concise state-ofthe-
art survey of the experimental investigations on the FRP-concrete composite bridge deck under
developing in Korea is presented.
Experimental Studies on Mechanical Properties of Rock Joints under Dynamic Loading
Authors: Li Hai Bo , Feng Hai Peng , Liu Bo , Li Jun Ru
Published: March 2009

In order to study the strength and deformation properties of rock joint under different
shear velocities, normal stresses and undulation angles, series testes are conducted by a RMT-150C
testing machines with artificial concrete rock joint samples in the present paper. Base on the
experimental results, it can be found that the peak shear strengths decrease with the increment of
shear velocity, and the decreasing rates tend to decrease with the increasing shear velocity. The
shear strength of rock joints increase with the increasing undulation angles, and linearly increase
with the increment of normal stress. It is also indicated that the shear stiffness increase with the
increasing normal stress, undulation angle as well as the shear velocity with a decreasing tendency.
Measuring Elastic Properties of Circular Tube Made with Thermoplastic Composites
Authors: Lee Dong Joo
Published: March 2009

Five methods are used to measure values of circumferential Young’s modulus and three
methods are used to obtain shear modulus using the closed and open ring specimens. Based on the
assumption that the technique using a strain gage must yield the correct value of Young’s
modulus, the technique using a closed ring specimen gives more consistent results than the
technique using an open ring specimen. For the simplicity of measurement, the technique using a
closed ring specimen under compression can be used as long as the thickness of the used
specimen remains thin enough to neglect the effects of shear deformation. To measure the shear
modulus, G12, both techniques using the open and closed ring seems to have the same trend as a
function of thickness. As expected from the loading scheme, the technique using an open ring
gives more consistent results for the shear modulus.
Microwave Curing and Its Application to Aircraft Structure Repair
Authors: Zhang Jian Hua , Dai Yong Chao
Published: March 2009

Microwave curing is a kind of technique that heat up the adhesive containing pole
molecule by means of microwave and let it curing rapidly. The characteristic of microwave curing
is discussed, and the technique and application of microwave curing are introduced.
Evaluation of Dimple Treatment for GFRP/Metal Co-Cured Joint
Authors: Matsuzaki Roysuke , Shibata Motoko , Todoroki Akira
Published: March 2009

Since composite materials have high specific strength and stiffness, they are used
for many fields such as aerospace and marine structures. According to such utilities, joining method
between composites and metals must be developed. In this study, dimple treatment is carried out as
a new reinforcing method for FRP/metal co-cured joint. Dimple treatment is applied to the adhesive
surface of metal so that resin of FRP permeates into dimples and the strength of joints increases. It
is revealed that dimple treatment achieves as high bonding strength as chemical surface treatment.
Characteristic Fracture Assessment of a Rivet Joint for Hybrid Composite Laminates under Static and Fatigue Shear Loads
Authors: Jung Dal Woo , Choi Nak Sam
Published: March 2009

Fatigue fracture behavior of a hybrid composite joint with riveting was evaluated in
comparison to the case of static fracture. Hybrid composite joint specimens for shear test were made
with layers of carbon fiber/epoxy composite and stainless steel. Characteristic fracture behaviors of
those specimens were obviously different under static and cyclic loads. Static shear loading showed
the fracture of a pure shear mode, whereas cyclic fatigue-shear loading caused the local stress
concentration of a tensile mode and thus brought about the tensile fracture at that site. Experimental
results obtained by static and fatigue tests were considered in modifications of design parameters of
the hybrid joint.
Dynamic Instability of Delaminated Composite Plates under Parametric Excitation
Authors: Yeh Meng Kao , Tung Kuei Chang
Published: March 2009

The dynamic instability behavior of delaminated composite plates under transverse
excitations was investigated experimentally and analytically. An electromagnetic device, acting like
a spring with alternating stiffness, was used to parametrically excite the delaminated composite
plates transversely. An analytical method, combined with the finite element method, was used to
determine the instability regions of the delaminated composite plates based on the modal
parameters of the composite plate and the position, the stiffness of the electromagnetic device. The
delamination size and position of composite plates were varied to assess their effects on the
excitation frequencies of simple and combination resonances in instability regions. The
experimental results were found to agree with the analytical ones.
Experimental and Finite Element Characterization of the Crippling Failure of Composite Stiffeners
Authors: Kweon Jin Hwe , Choi Sang Min , Son Hee Jin , Choi Ji Young , Choi Jin Ho , Che Woo Seong
Published: March 2009

Progressive failure analysis based on the complete unloading method was conducted to
investigate the crippling failure of carbon/epoxy composite stiffeners under axial compression. A
modified arc-length algorithm was incorporated into a nonlinear finite element method to trace the
equilibrium path after local buckling. For the validation of the finite element method, several
carbon/epoxy Z-section stiffeners were tested in compression. The finite element results on the
buckling and crippling stresses showed good agreement with the experimental results.
Development of New-Type Similar Materials of Geomechanics Models Test for Geotechnical Engineering
Authors: Zhang Qiang Yong , Zhu Wei Shen , Li Yong , Guo X.H.
Published: March 2009

Geomechanics model test can simulate the real excavation process of geotechnical
engineering and the mechanics deformation properties of the rockmass prototype on the condition
of meeting the similar principles. In order to conducting geomechanics model test, similar
material which can meet similar mechanical properties must be used. It is only after conducting a
massive mechanics experiments that a new-type similar materials called iron crystal sand is
developed in this paper. This material consists of iron ore powder, blanc fix, quartz sand, gypsum
powder and rosin alcohol solution which are evenly mixed in certain proportion and pressed
together. The iron ore powder, blanc fix and quartz sand among them are main materials. The
rosin alcohol solution is the cementing agent and gypsum powder the regulator. The material
mechanics experiments show that this material has following outstanding characteristics: high
volume-weight, wide variable mechanical parameters, stable performance, low price, quick
drying, simple processing and innocuity. It can simulate most rockmass material from soft to hard
ones and can be widely used in geomechanics model tests in fields of energy sources,
transportation, water conservancy and mining.
Impact Damage Behavior of Glass/Epoxy Laminates for Railway Vehicle at Low Temperature
Authors: Kang Ki Weon , Yang Seung Yong , Kim J.H. , Kim Jung Kyu , Kim Heung Seob , Kim H.J.
Published: March 2009

This paper deals with the damage behavior of glass/epoxy composite laminates 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 of the laminates, the impact resistance
parameters were employed to evaluate damage resistance of glass/epoxy laminates. As results, it
was found that the temperature changes affect the damage resistance capacity of glass/epoxy
laminates.
Experimental Study on Mechanical Property of Thermo-Mechanical and Hydro-Mechanical Coupling Condition for a Sandstone
Authors: Zhou Qing Chun , Li Hai Bo , Yang Chun He , Luo Chao Wen
Published: March 2009

The mechanical properties of rock under high temperature, high geostress and high pore
pressure are the basic and important information to assess the safety of underground engineering in
west China. Based on the environmental conditions of the west route of south-to-north water
transfer project in west China, a series of triaxial tests at confining pressures (0 to 60MPa) and
temperatures (25°C to 70°C) as well as pore pressure (0 to 10MPa) have been conducted for a
sandstone. It is reported that under the temperatures varying from 25°C to 70°C, the strength of the
rock increases with the increment of confining pressure, while the deformation modulus of the rock
doesn’t change distinctly with the increment of confining pressures. It is also indicated under the
temperatures condition in the experiments, when the confining pressure is lower than 40MPa, the
strength of the rock increases with the increment of temperature, whereas when the confining
pressure is higher than 40MPa, the strength of rock tend to decrease with increment of temperature.
It is further shown that the strength decreases with increasing pore pressure, and the decreasing
rates tend to decrease with the increment of confining pressures.
New Type Geo-Mechanical Similar Material Experiments Research and Its Application
Authors: Li Shu Cai , Wang Han Peng , Zhang Qiang Yong , Li Yong
Published: March 2009

It is very important to choose a similar material which simulates rock mass correctly in
geo-mechanics model test. In this paper, we introduce similar material research status and analyze
the principle of selecting and compounding. According to the experiences of similar material
research, we develop a new similar material (we call it iron barites sand cementation material,
abbreviate IBSCM) through hundreds of compounding experiment. This similar material is made
up of iron ore powder, barites powder, sand, rosin, alcohol and gypsum powder. Iron ore powder,
barites powder and sand are main materials, the solution of rosin and alcohol is glue, and gypsum
powder is regulator. Specimen mechanics tests show that different rock mass can be simulated by
the model materials with different materials compounding. The new similar material is easy to
buy and its price is cheap, and it has some advantages, such as high density, stable performance,
easy dryness, and easy cutting. The new similar material can simulate a lot of rock mass, so it is
an ideal similar material. At last, we apply this new type similar material to tunnel
geo-mechanical model test and gain the ideal result.
Experimental Research on Failure Mechanism of a CVI-Fabricated Ceramic Matrix Composite under Compression
Authors: Guan Guo Yang , Jiao Gui Qiong , Huang Tao
Published: March 2009

Mechanical tests have been conducted to understand compressive behavior of a plain
weave C/SiC composite, especially to investigate the failure mechanism. The stress-strain curves of
this composite show linear feature in compression. The specimens fail along a flat plane 13°~15° to
the weave plane, running across four typical regions in the bulk: weft bundle, warp/weft interface,
warp bundle, and inter-ply. According to the observed fracture route, four basic failure modes are
schematically presented. Cracks form and develop in these areas along fiber/matrix interphase or
within matrix, depending on the strength competition between interphase and matrix. The fracture
mechanism reveals dependence of compress strength on matrix abundance between and within
bundles. Based on the failure modes new method for compress strength prediction can be further
investigated.