bluuebunny/crossref_metadata_2025 huggingface dataset:
Demonstration of the Formation of Porous Silicon Films with Superior Properties Formed on Polished (100) Si with Screen-Printed Back Contacts
Authors: Singh Priyanka , Sharma Shailesh N. , Bhagavannarayana G. , Husain M. , Lal M.
Published: March 2009

Porous silicon (PS) layers were formed by anodization on polished substrates of (1 0 0) Si at different current densities for a fixed anodization time of 30 mins. using different screenprinted/ evaporated back contacts (Ag, Al) respectively. The PS films has been characterized by high resolution X-ray diffraction (HRXRD), photoluminescence (PL), Scanning Electron Microscopy (SEM) and Fourier Transform Infrared (FTIR) techniques respectively. Porosity and thickness of PS layers were estimated by gravimetric analysis. The properties of PS formed using screen-printed Ag & Al as the back contacts (SP-(Ag/Al)) was found to be superior as compared to the corresponding films with evaporated back contacts (EV-(Ag/Al)). The PS formed with screenprinted Ag & Al-back contacts shows better crystalline perfection, higher stability, higher PL efficiency and negligible PL decay compared to that formed with evaporated Ag & Al- as the back contact for the same current density and time of anodization.
DFB Lasers with Tilted Waveguide for Multi-Wavelength Generation
Authors: Chong Lip Fah , Teng Jing Hua , Lim Ee Leong , Ang Norman Soo Seng , Dong J.R. , Chua Soo Jin
Published: March 2009

In this paper, we present the theoretical investigation of index-coupled distributed
feedback (DFB) laser with tilted single mode ridge waveguides. By tilting part of the ridge
waveguide in various degrees, DFB laser with manifold effective grating periods can be realized.
The structure is analyzed using couple mode theory in matrix form based on threshold analysis.
Important parameters of DFB laser like resonant frequency and threshold gains are obtained by
solving the eigen-equation. The results indicate not only that the lasing frequency is modulated by
the waveguide titling angle, but also large Gain Margin (GM) can be achieved at the threshold
condition which enhance the stable single mode operation in index-coupled DFB laser.
Charge Effect in Organic Field-Effect Transistors - Analyzing Hall Measurements in the Accumulation Layer
Authors: Kwok Harry L.
Published: March 2009

Hall measurement is an effective means to measure carrier density and mobility in metals
and semiconductors. This work examined the carrier mobility determined in the accumulation layer
of organic field-effect transistors (OFETS) and proposed a method to explain data taken from
rubrene single-crystal devices. The model was used to extract information on the trap states and the
properties of the transport layer at different temperature.
Growth, Surface Morphology and Optical Properties of Gallium Nitride Nanowires
Authors: Suresh Kumar V. , Kumar J.
Published: March 2009

We report on the growth mechanism, structural and optical characterstics of
Gallium nitride nanowires prepared on sapphire substrates (0001) by reacting metal
gallium with Gallium nitride powder and ammonia in the temperature range of 800 to
1050°C. GaN nanowires samples were characterized by using X-ray diffraction technique
which shows wurtzite structure of GaN nanowires and the lattice parameters are
calculated. Scanning electron microscopy images reveals that the dimension of the
nanowires are around 60 – 80 nm and the length of 1 - 2 millimeters. Three Raman
modes of GaN have been observed at frequencies 530, 554 and 564 cm-1.
Photoluminescence spectrum reveals the band edge at 3.4 eV and gives yellow
luminescence.
Conspicuous Presence of Higher Order Transitions in the Photoluminescence of InxGa1-xN/GaN Quantum Wells
Authors: Biswas Dipankar , Das Tapas , Kabi Sanjib , Kumar Subindu
Published: March 2009

For successive annealing stages the photoluminescence (PL) peaks of InXGa1-XN/GaN
quantum wells (QWs) shift initially towards red which is followed by a blue. This phenomenon
contradicts the usual monotonic blueshift. We have found that the phenomena can be explained
properly only if we consider recombinations from the higher sub-bands to be present in the PL of
the InXGa1-XN/GaN QWs, which is not usual. When a strong piezoelectric field exists across a QW,
as encountered in InXGa1-XN/GaN QWs, the probability of optical transitions from higher sub-bands
of the QW become more probable. In this paper this theory has been established from experimental
results.
The Study of Femto-Second Laser Induced Damage Threshold on Semi-Insulating GaAs Wafer
Authors: Li Chao Yang , Wang Yong Gang
Published: March 2009

We demonstrated an experiment of femtosecond-laser damage threshold on GaAs wafer, the damage threshold was measured from 50 to 400fs. The mechanism was discussed through injection power, pulse duration and ablation profile. The results showed that the damage threshold increased with the pulse duration, the relationship between diameter of ablation hole and laser power density was also analyzed. It was concluded that the main factor affecting the damage threshold was photon ionization and collision ionization.
Nitrogen Interstitial Defects in GaNAs Films Grown by MOCVD
Authors: Sentosa Deny , Tang Xiao Hong , Chua Soo Jin , Yin Zong You
Published: March 2009

Photoluminescence (PL) measurement shows an additional peak with stronger and broader emission at lower photon energy besides the energy band gap transition emission from GaNAs epilayer grown by MOCVD. This emission is assigned as nitrogen-nitrogen interstitial defect related emission. Effect of V/III ratio during the MOCVD growth on this defect related emission peak has been investigated. The combination of optimum V/III ratio during the MOCVD growth and post-growth rapid thermal anneal (RTA) can eliminate this defect emission peak and at the same time the GaNAs’ band gap emission has been greatly improved. The PL spectra contain a single, narrow, and high intensity GaNAs’ band gap transition emission after the RTA annealing. The optimum V/III ratio for growing the GaNAs films with N content < 3.5% is around 20.
Optical and Piezoelectric Properties of ZnO Nanowires and Functional Polymer-Based Nanocomposites
Authors: Pyrz Ryszard
Published: March 2009

Molecular dynamics simulations are employed to study electronic and mechanical
properties of smallest ZnO nanowires. It has been shown that the electronic band structure of
nanowires varies with uniaxial strain and this property can be used for sensing deformation state
when nanowires are embedded in a polymer matrix. A new atomic strain concept is formulated that
allows calculation of continuum quantities directly within a discrete atomic (molecular) system.
Molecular modeling and strain calculations have been performed on ZnO/polypropylene
nanocomposites and compared with a carbon nanotube/polypropylene system. The simulation cell
of nanocomposite has been subjected to uniaxial tension along an inclusion axis and the analysis
has been performed for seven deformation steps with equilibration runs after each step. Both nanoinclusions
follow global nanocomposite strain to a certain loading and then both exhibit
deformation lag as loading level increases. This is clear evidence that both systems are prone to
interfacial sliding. The sliding is more significant with the ZnO nanowire as compared to carbon
nanotube, which is also evidenced in weaker interaction of this system.
Analysis of Casting Roll Temperature Field during Twin-Roll Thin Strip Casting
Authors: Zhang Xiao Ming , Jiang Zheng Yi , Li Hei Jie , Fan Z. , Liu Xianghua , Wang Guo Dong
Published: March 2009

In twin-roll strip casting process, the temperature variation of casting roll can result in
roll thermal stress and fatigue. It not only affects the thermal deformation of casting roll and the
generation of the roll surface cracks significantly, but also influences the surface quality, shape and
profile of the produced strip, and the service life of the casting roll. In this paper, a 3D coupling
thermal-flow finite element modelling has been conducted. For twin-roll casting of stainless steel,
the influences of the casting speed and liquid level in molten pool on the temperature field of
casting roll have been simulated and discussed. The developed model is very helpful in optimising
the processing parameters and the design of casting roll during twin-roll thin strip casting.
Manufacture, Wet and Dry Corrosion, and Plasma Nitridation of Novel Nanocrystalline Ni-Cr Nanoparticle Nanocomposites: A Brief Review
Authors: Peng X.
Published: March 2009

The paper is a short review of the fabrication, wet and dry corrosion, as well as plasma
nitridation of novel Ni-Cr nanocomposites. The nanocomposites, fabricated by co-electrodeposition
of Ni and nanometer-sized Cr particles, have the nanocrystalline Ni matrix dispersing the second
phase of nanoparticles. They, compared to conventionally coarse-grained Ni-Cr alloys, exhibit
dramatically increased resistance to liquid corrosion in a 3.5% NaCl solution, and to hot corrosion
under molten salt of Na2SO4-Na2SO4-NaCl at 700oC. The reason for these is correlated with the
unique structure of the nanocomposite, which guarantees the fast diffusion of chromium from the
composite interior to the corrosion front for the formation of a continuous, protective layer of
chromium oxide-rich films severing the composites from environmental corrosive species. During
plasma nitridation at 560oC the Ni-Cr nanocomposite forms a thick nitriding layer which cannot be
achieved on the conventional alloy counterpart with a comparable composition, due to enhanced
nitridation kinetics.
The Development of a New Image Acquisition & Analysis System for 3D Surface Measurements Using Confocal Laser Scanning Microscopy
Authors: Peng Zhong Xiao , Tomovich Steven
Published: March 2009

Quantitative surface measurement is an important field in many applications including
materials science and engineering quality control. A non-destructive and versatile technique for
quantifying surface roughness in 3D is Confocal Laser Scanning Microscopy (CLSM). However,
this technique has not been widely accepted to use for quantitative surface measurements due to
limited work on it. The project has researched the suitability of using the system for surface
characterization and appropriate settings for image acquisition for quantitative surface analysis.
Based on the above fundamental work, this study has developed and presented a comprehensive
approach of using the system for quantitative surface characterization through image processing, 3D
image construction, image stitching and numerical image analysis. The surface characterization
results presented in the paper have demonstrated that the system can be used to accurately measure
surface roughness of engineering surfaces.
Effect of Surface Texture on Deformation Behavior of Asperity in Cold Metal Forming
Authors: Wei Dong Bin , Jiang Zheng Yi , Lu Cheng , Tang Ying De , Tieu A. Kiet
Published: March 2009

It was impossible to obtain the transverse friction along the strip width in most
previous studies of cold strip rolling because the surface roughness lays were assumed to be vertical
to the rolling direction. In this study, several types of oblique roughness textures were manufactured
on aluminum samples and compression tests were carried out to obtain the effect of different
textures on the deformation behavior of surface asperity. Different surface textures resulted in very
different peak value of stress. It was found that stress was high and changed dramatically at the
initial compression stage but tended to be stable when the total reduction increased. The asperity of
which the top angle is 160° showed relatively high resistance to deformation.
Effect of Fully Porous-Coated (FPC) Technique on Osseointegration of Dental Implants
Authors: Rungsiyakull Chaiy , Li Qing , Li Wei , Appleyard Richard , Swain Michael
Published: March 2009

This paper provides a preliminary understanding in biomechanics with respect to a fullyporous-
coated (FPC) dental implant. A 2D multiscale finite element model is created for a typical
dental implantation setting. Under a certain mastication force (<200N), a global response is first
obtained from a macro-scale model (without coated surface morphology details), and then it is
transferred to a micro-scale model (with coated surface morphology details), which allows
determining a local biomechanical field. To facilitate the study in bone remodelling, strain energy
density and equivalent strain are analysed respectively. Different porosities of coating are taken into
account in this study to investigate the effect of FPC materials on these typical remodelling stimuli.
The results evidently reflect the osseointegrative benefits generated from surface coating. The result
reveals that increasing in particle sizes has significant effect on biomechanical response.
Finite Element Analysis of Plant Cell Wall Materials
Authors: Kha Hung , Tuble Sigrid , Kalyanasundaram Shankar , Williamson Richard E.
Published: March 2009

Illuminating fundamental aspects of plant cell wall mechanics will lead to novel
biological and engineering inspired strategies for application in the cotton and wood fiber industries
and in developing novel plant-derived materials that are increasingly seen as environmentally
friendly alternatives. The stiffness properties of cell wall polymers such as cellulose microfibrils
and xyloglucans are known but the relationship between the composite structure of the wall and its
effective stiffness remains poorly understood. Understanding this relationship is important to
engineers using and designing plant-derived materials and to biologists studying plant growth. We
have developed a software system to generate microfibril-xyloglucan networks resembling those
found in cell walls. Finite element analysis was implemented to predict the effective Young’s
modulus of varying sizes of the microfibril-xyloglucan network. Results from the finite element
models show that the network’s effective moduli of the cell walls having microfibrils parallel to
applied loadings are relatively high (~90-215MPa) compared with those of the walls having
randomly oriented microfibrils (~20-47MPa). The walls having microfibrils parallel to each other
but perpendicular to applied loadings have lowest stiffness (~17-118kPa). The Young’s moduli are
significantly lower than those of its constituent polymers and generally in agreement with
experimentally measured values.
In Search of a Parameter to Distinguish Viable from Non-Viable Articular Cartilage – Indentation and Ultrasound Studies
Authors: Brown Cameron P. , Crawford Ross , Oloyede Adekunle
Published: March 2009

It has been recently established that mechanical indentation does not sufficiently
discriminate between normal and degraded articular cartilage. Consequently, we have carried out
preliminary research to develop and evaluate a number of indices and parameters that can
characterise and categorise the tissue into viable and degraded types relative to functional integrity.
In this paper, we report the outcome of correlation studies between the instantaneous structural
rebound following unloading from a known level of indentation and reflected ultrasound signals,
analysed in the frequency domain. We subjected 137 samples from 10 normal and 10 osteoarthritic
joints to ultrasound waves and mechanical indentation-rebound tests, and determined the degree of
correlation between the instantaneous rebound and the principal components of the ultrasound
spectra and further investigated this using canonical discriminate analysis that was fitted with a
general linear model. Our results demonstrate a strong correlation between rebound and ultrasound
results, leading to the conclusion that it is possible to determine the mechanical and structural
viability of articular cartilage using non-contact methods.
Physical Phenomena of Thermoplastic Articles in the Vicinity of Their Glass Transition Temperatures
Authors: Kharchenko Sam , Huang Jack
Published: March 2009

It is well known that environmental conditions impact the performance of thermoplastic
articles, therefore requiring selection of appropriate raw materials. Nevertheless, frequently due to
business reasons, when selecting a material, the rigor of understanding the fundamental physical
events responsible for the desired performance is shortchanged. In this study, we investigate the
effects of cyclic heat history on the dimensional stability of articles made with commercial grade
rigid thermoplastic resins, particularly, in the temperature range close to the material’s glass
transition temperature, as more materials are used in hot & arid environments. The two physical
events identified as most relevant to desired article performance are the relaxation of the processinduced
residual stresses within the material and the dynamic phenomena brought about by the
material’s coefficient of thermal expansion, CTE. We find that the periodic development of convexconcave
surfaces on an article matches the periodic development of a non-uniform temperature
gradient within the article. We demonstrate that this periodic heat exposure leads to an irreversible
concave deformation of the article’s exposed surface. Moreover, articles exhibit this deformation
phenomenon regardless of the level of the initial process-induced stresses. We offer explanations of
these behaviors and discuss their practical implications.
Characterization of Virtual Nano-Structures through the Use of Monte Carlo Integration
Authors: Herrera Luis F. , Do Duong D. , Birkett Greg R.
Published: March 2009

The determination of the properties of porous solids remains an integral element to the
understanding of adsorption, transport and reaction processes in new and novel materials. The
advent of molecular simulation has led to an improved understanding and prediction of adsorption
processes using molecular models. These molecular models have removed the constraints of
traditional adsorption theories, which require rigid assumptions about the structure of a material.
However, even if we possess a full molecular model of a solid, it is still desirable to define the
properties of this solid in a standard manner with quantities such as the accessible volume, surface
area and pore size distribution. This talk will present Monte Carlo integration methods for
calculating these quantities in a physically meaningful and unambiguous way. The proposed
methods for calculating the surface area and pore size distribution were tested on an array of
idealised solid configurations including cylindrical and cubic pores. The method presented is
adequate for all configurations tested giving confidence to its applicability to disordered solids. The
method is further tested by using several different noble gas probe molecules. Finally, the results of
this technique are compared against those obtained by applying the BET equation for a range of
novel materials.
Design of Periodic Microstructural Materials by Using Evolutionary Structural Optimization Method
Authors: Patil Sachin , Zhou Shi Wei , Li Qing
Published: March 2009

Despite significant success in developing various periodic composites, the challenge
remains how to more efficiently design the base cell so that one or more physical properties can be
attained. In this paper, the material design problem is formulated in a form of the least square of the
difference between the targeted and designed values. By minimizing the objective subject to volume
constraints and periodic boundary conditions, an optimal material distribution in base cell can be
generated. Different from existing methods, this paper shows how to use the Evolutionary
Structural Optimization (ESO) method to design composite material attaining to thermal
conductivity defined by the Hashin-Strikman (H-S) bounds. The effectiveness of this method is
demonstrated through several 2D examples, agreeing well with commonly known benchmarking
microstructures.
Prediction of Defects in PZT Thin Film Using Ab-Initio Method
Authors: Zhang Z. , Lu L. , Wu P. , Shu C.
Published: March 2009

This paper reviews our systematic and exhaustive studies on the lead zirconate titanate
doped with dopants using ab initio density functional theory calculations in order to understand the
mechanisms behind the dopings. Different candidates of dopants were selected by screening the
periodical table of elements. In our studies, group VA, VIA elements (B-site donors), group IIA
elements (A-site donors), group IIIB elements (B-site acceptors), and group VB elements (A-site
donor, B-site acceptor/donors) are investigated as dopants in PZT. We found that there exist
different mechanisms behind the improved ferroelectric properties, especially the fatigue behaviors.
For donors doping, diluted oxygen vacancy concentration and reduced electronic suppression of
polarization contribute to the fatigue-free behaviors of donor doped PZT. On the other hand, for
acceptor doping, acceptor-oxygen-vacancy-acceptor clusters are energetically preferred, which
greatly reduce the oxygen vacancy mobility and the domain pinning effects. We expect that this
study could provide important information for the experiments on PZT-based materials.
Environmental Response of Plasma Sprayed Nanostructured Coatings
Authors: Ahmad Zaki , Ahsan M.
Published: March 2009

Erosion corrosion and environmental chamber corrosion studies conducted on plasma
sprayed samples from three different spray dried and densified nanopowders showed good
resistance to corrosion. A dense, uniform and even distribution of splats and small number of
microvoids and pores offered a high resistance to erosion-corrosion in sodium chloride polystyrene
slurry. The coatings offer a high resistance in salt spray chamber environment.
Residual Thermal Stresses in a Fe3Al/Al2O3 Gradient Coating System
Authors: Wang Jiang Ting , Hodgson Peter , Zhang Jing De , Yang Chun Hui
Published: March 2009

To combine the merits of both metals and ceramics into one material, many researchers
have been studying the deposition of alumina coating using plasma spray on metal substrates.
However, as the coatings are deposited at a high temperature, residual thermal stresses develop due to
the mismatch of thermal expansion coefficients of the coating and substrate and these are responsible
for the initiation and expansion of cracks, which induce the possible failure of the entire material. In
this paper, the residual thermal-structural analysis of a Fe3Al/Al2O3 gradient coating on carbon steel
substrate is performed using finite element modelling to simulate the plasma spray. The residual
thermal stress fields are obtained and analyzed on the basis of temperature fields in gradient coatings
during fabrication. The distribution of residual thermal stresses including radial, axial and shear
stresses shows stress concentration at the interface between the coatings and substrate. The mismatch
between steel substrate and composite coating is still the dominant factor for the residual stresses.
Bone Formation Based on the Turing Model under Compressed Loading Condition
Authors: Jia Li Hua , Gheni Mamtimin , Eli Hazirti , Abdikerem Xamxinur , Kikuchi Masanori
Published: March 2009

In this paper, the iBone (Imitation Bone) model which is coupled with Turing
reaction-diffusion system and FEM, is used. The numerical simulation of bone forming process by
considering the osteoclasts and osteoblasts process are conducted. The results shown, that the bone
mass is increased with increase of the initial load value, then fibula and femur bones are obtained
respectively by keeping the required bone forming value. The different bone shapes are obtained by
changing the both bone keeping value and the compressing force value. When set larger bone keeping
value by keeping larger constant compressing force value, bone shape as a pipe with hole just like
femur, when set smaller bone keeping value by keeping the smaller constant compressing force value,
it is close to solid pillar as like fibula.
Effective Use of Commercial FEM Software in 2-Dimentional Crack Problems
Authors: Nisitani Hironobu , Ushijima Kuniharu , Chen D.H. , Saimoto Akihide
Published: March 2009

Finite element method (FEM) is used widely for various structural problems. However, in
general, it is difficult to guarantee the accuracy of results obtained by commercial software of FEM. In
this paper, a practical finite element technique for calculating the stress intensity factors with high
accuracy is proposed. This technique is based on the characteristics of stress field due to a crack. In
this study, the proposed method is applied to 2-dimentional crack problems.
Elastic-Plastic Mechanics Analysis on Stability of Coal Pillar
Authors: Gao Wei
Published: March 2009

Because it is very important to study the coal pillar stability, a lot of methods to do this have
been proposed. But most of those methods do not consider the nature of coal material and only study
the coal pillar that is level. To solve this problem suitably, here a new method is proposed. In this
method, the plastic softening nature of coal material is considered. And also, the coal seam pitch is
considered in our analysis. Based on real deformation of coal pillar and the previous study, the
limiting equilibrium method is applied. At last, the rationality of our method is verified through a strip
mining engineering example. And the results show that, the computing results of our method are
coincided with measuring results very well and our method can be applied in real engineering practice
very well.
Intelligent Monitoring Technique for Working Status of Shenzhen Citizen Center Roof Truss Structure under Wind Load
Authors: Liu Hui , Qu Wei Lian , Wang Jin Wen
Published: March 2009

Taken the roof of Shenzhen citizen center with huge size and very complicated structure
as the engineering background, the intelligent methods of safety monitoring of integer behavior for
large span complex space truss structures under wind-excited by the data-acquisition based on
limited sensors are discussed in detail in this paper. In order to acquire the working status of the
whole structure, the method that can be adopted to obtain structural real-time response under wind
load is listed as follows, step1: to identify the wind load; step 2: to update the structural finite
element model; step 3: to measure peak factor of structural response; step 4: to directly analyze the
structural real timely response. The first two steps are key techniques among all the steps of the
method.
The weighted proper orthogonal decomposition technique is adopted to identify the characteristics
of wind pressures at all internal nodes on the truss structural roof in the frequency domain by using
the measured wind pressure data from non-uniformly taps. Moreover, by using measured structural
acceleration response from finite acceleration sensors on the structure, the accurate analytical model
of the structure is established by updating the finite element model based on modifying node
parameters. Then, the monitoring result of entire truss structure in the worst working performance
in every ten minutes is obtained according to positive deductive method with the measured mean
wind speed and wind direction from anemometer and peak factor acquired from finite strain gauges
on the truss structure in every 10 minutes. Finally, based on the above-mentioned method, working
status intelligent monitoring system is established, which can display the stress level and safe class
of all structural members.
Static and Dynamic Analysis of Wind Turbine Tower Structure
Authors: Xu Yan , Sun Wen Lei , Zhou Jian Ping
Published: March 2009

This paper presents static and dynamic analysis of tower structure supporting a 600KW
wind turbine based on the theory of FEM. According to the static and dynamic characteristics of
tower structure, the works about simplified models and confirming loads and boundary condition are
discussed. In static analysis, under different work conditions the load bearing capacity of tower
structure is analyzed with door opening in different directions and without door opening. In dynamic
analysis, in order to address the impacts of the foundation on structure, the research discusses the
natural frequency and eigenmode from the first sixth modes at the assumption of fixed base and the
elastic subgrade. Comparative studies have been performed on the results of the above analysis and
some useful conclusions are drawn pertaining to the effectiveness and accuracy of the various
models used in the work. Our research work lays a solid foundation of the further static and dynamic
analysis.
Dynamic Characteristics and Mode Selection of High Tower
Authors: Wang X.L. , Liu Hui , Li Hai Bo
Published: March 2009

The dynamic characteristics of a TV tower with 610m in height is actively analyzed by
using commercial package ANSYS in this study. The mode selection is carried out by determining the
modal mass participation ratio. The observations made based on numerical investigation demonstrate
that the natural frequencies of the high rise unsymmetrical tower are substantially close and the modal
displacement of the antenna is much larger than that of the major tower. In order to select the major
mode shapes, the modal mass participation ratios of the first 30 modes are calculated and at least first
10 mode shapes should be considered when investigating the seismic responses. It is seen that the
mode shapes whose vibration directions are paralleled to the short axis of the elliptical core tube are
critical to the structural seismic responses. In this direction, the mass participation ratios of the first
three mode shapes add up to 0.63, the 10 modes, the sum of whose modal participation ratio is 0.8184,
are selected in order. Therefore, at least 10 modes should be involved in the analysis of structural
seismic responses.
Effect of Size and Location of a Weld Defect on Fatigue Life for Argon-Arc Welded Titanium Alloy Joint
Authors: Liu J.Z. , Wu Xue Ren , Wang L.F. , Hu B.R. , Chen B.
Published: March 2009

Analytical studies were made on effect of size and location of a weld defect on fatigue
life for argon-arc welded titanium alloy joint. In the analyses, a weld defect was assumed as an
initial crack, and the crack growth life was taken as total fatigue life. By using the Isida and
Noguchi’s stress intensity factor solution for a plate containing an embedded elliptical subsurface
crack under tension, the life prediction code FASTRAN3.9 was revised. A small crack methodology
based on the plasticity-induced crack-closure concept and the effective stress intensity factor range,
Keff , was used to predict the total fatigue life of welded joint, and to study the effect of the size
and location of weld defect on fatigue life by means of the revised FASTRAN3.9 code. Limited
amounts of experimental data were used to make comparison with the predictions. The predicted
fatigue lives are in reasonable agreement with experiments, and the effect of both the size and
location of the weld defect on fatigue life was found to be significant.
Taylor Series Numerical Method in Structural Dynamics
Authors: Zhao Li Bin , Zhang Jian Yu , Zhao You Xuan
Published: March 2009

Taylor series numerical method is a novel time integration method for structural dynamics.
In comparison with the well-known ones, Taylor series method has high accuracy and good
convergence characteristics and thus is a good alternative for solving structural dynamics problems.
In the paper, the recursive formulae of Taylor series numerical method in linear and nonlinear
structural dynamics are derived. The desired user routine in Fortran 90, which was compiled and
linked into the general software ANSYS program, is designed and programmed. User-defined menus
are constructed via the User Interface Design Parameter. Numerical examples illustrated the validity
of the customized plug-in. The research in this paper promotes the algorithm application in
complicated engineering problems.
Preliminary Design Analysis of a Hot Gas Duct for the NHDD Program at Korea
Authors: Song Kee Nam , Lee Hyeong Yeon , Kim Yong Wan , Lee Soo Bum
Published: March 2009

Korea Atomic Energy Research Institute (KAERI) is in the process of carrying out a
Nuclear Hydrogen Development and Demonstration (NHDD) Program by considering the indirect
cycle gas cooled reactors that produce heat at temperatures in the order of 950°C. A coaxial doubletube
hot gas duct (HGD) is a key component connecting the reactor pressure vessel and the
intermediate heat exchanger (IHX) for the NHDD program. Recently, a preliminary design
evaluation for the hot gas duct of the NHDD program was carried out. These preliminary design
activities include a preliminary decision on the geometric dimensions, a preliminary strength
evaluation, an appropriate material selection, and identifying the design code for the HGD. In this
study, a preliminary strength evaluation for the HGD of the NHDD program has been undertaken
based on the HTR-10 design concepts. Also, a preliminary evaluation of the creep-fatigue damage
for a high temperature HGD structure has been carried out according to the draft code case for
Alloy 617. Preliminary strength evaluation results for the HGD showed that the geometric
dimensions of the proposed HGD would be acceptable for the design requirements.
Erosion Properties of Molybdenum Coatings Sprayed by Electro-Thermal Explosion Ultra-High Speed Spraying
Authors: Li Bin , Liu Zong De , Zhao Li Ping , Ma Yi Min
Published: March 2009

Molybdenum coatings are commonly used in the industry for protection against wear. With
an aim to investigate the erosion properties of this coating, molybdenum coating was sprayed onto
both AISI 1045 and nickel-based superalloy (GH3039) substrate by electro-thermal explosion
ultra-high speed spraying process. Phase composition, microstructure and microhardness of the
coatings were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and
microhardness tester, respectively. Erosion tests of the coating at different particle impingement angel
and material sample temperature were performed on a GW/CS-MS type tester. The high erosion
resistance of the coating can mainly be attributed to high hardness, low porosity and metallurgical
bonding between the coating and the substrate.
The Failure Process Analysis on a Numerical Model of a Branching-Out Tunnel under Lateral Overload Action
Authors: Zhang Qiang Yong , Li Yong , Zhu Wei Shen , Zhang Jian Guo , Wang Han Peng
Published: March 2009

As the implementations of the western development in China, more and more tunnels
will get through the western mountains in China. In order to economize the construction costs, a
new type of underground structural form called branching-out tunnel must be applied. The failure
process of the branching-out tunnel under lateral overload action is also greatly complicated, which
is related with the depth of the mountains, the branching-out angle, the in-situ stress field, the
thickness of the middle wall and so on. This paper uses the 3D-physical model of geo-mechanical
model tests to study the stability and failure process of this complicated structure, especially the part
of the middle wall. The physical model is built up in a new kind of analogy material. In the process
of the whole experiments, different lateral pressures imposed on both of the lateral planes of the
physical model. According to different lateral pressures, we have attained the change of the stress
and displacement field and looked into the failure process of the pivotal positions in the
branching-out tunnel. We also use finite element method analysis software RFPA (Realistic Failure
Process Analysis) to simulate the whole failure process of the branching-out tunnel. Finally, we
have got the load-bearing safety reliability of this complicated structure through comparative
analysis of physical modeling and numerical simulation.
Nondestructive Corrosion Monitoring in Reinforced Concrete by Boundary Element Inverse Analysis
Authors: Suga Kazuhiro , Yoshida Masato , Ridha M. , Aoki Shigeru
Published: March 2009

This study proposes a monitoring method for corrosion on reinforced concrete structure
using inverse analysis approach. At first, we define an inverse problem to identify the real and
imaginary parts of the concrete conductivity and the impedance between concrete and steel. The
observation of the inverse problem is the electric potential on the concrete structure surface when the
AC impedance measurement is performed. The observation condition, such as layout of observation
point and type of observation, of the inverse is optimized. The optimization is achieved by
minimizing the average of eigen values of a posteriori estimate error covariance matrix based on the
Kalman Filter estimation algorithm. We show a numerical simulation to solve the inverse problem on
the optimized observation condition to evaluate the effectiveness of the condition. The simulation
shows the real parts of the concrete conductivity and the impedance are well identified but imaginary
parts of them are not. To overcome this difficulty, we evaluate the sensitivity of the imaginary part of
the impedance to the real part and the imaginary part of the electric potential. We find the possibility
that the observation of the imaginary part of the electric potential improves the estimation. Finally, a
numerical simulation is performed under the optimized observation condition considering the above
discussion. In the numerical simulation shows that considering the sensitivity of the parameters to the
potential improves the solution on the inverse problem.
Numerical Simulation of Corrosion under Different Solution Velocity
Authors: Adachi Hajime , Suga Kazuhiro , Hayase Masanori , Aoki Shigeru
Published: March 2009

A numerical simulation of corrosion in a tube is performed with the solution velocity effect
taken into account. A two dimensional tube, the cross-section of which is widening or narrowing with
increase in distance, is considered. The velocity distribution in the tube is calculated with the Finite
Volume Method (Open FOAM), and the derivatives of velocity with respect to the distance from the
tube wall is determined at any location of the tube. The corrosion rate of the tube wall is estimated
under the assumption that the corrosion rate depends on the velocity gradient, i.e. , it is estimated by
solving the Laplace equation under the boundary conditions given with the polarization curves
measured under various velocity gradients. The Boundary Element Method (3D-CAFE) is used to
solve the Laplace equation. It is shown that the distribution of corrosion rate, including the maximum
corrosion rate and its location, is different between the widening and narrowing tubes, even if the
average velocities in the two tubes are equal.
Research on Hardening the Surface of Laser and Anti-Tempering Property of Cast Steel Hot Roller
Authors: Xu Qiao Yu , Ahmat Kalbinur , Liu Xiang
Published: March 2009

Fine martensite could be gained in 70Mn2Mo cast steel roller after solidification by laser
treatment. The hardness and depth of hardened zone reached 920 HV (about 65HRC) and 0.6mm
respectively. After tempered in high temperature, the depth of hardened zone whose hardness was
maintained above 430HV was 0.4mm. These results showed the better anti-tempering property and
the higher hardness and hardened depth compared with water quenching and implied the greater
applied potentiality of laser strengthening.
Analytical Research on FEM and Dynamic Stress Test of Residue Plastic Film Suspension Recycling Machine
Authors: Wang Chun Yao , Xie Yong , Wang Xue Nong , Cheng Fa , Liu Yue , Chun Yuan Kong
Published: March 2009

This paper carried on mechanics analysis and the research to the Curved Rake Tine Frame
and Headstock of film recycling machine which could cut cotton stalk and recycle the used film
simultaneously. This machine was developed by the Institute of Agriculture Machine Xingjiang
Academy of Agricultural Sciences. This paper used servile methods to identify the structural
deficiencies such as Visualization Virtual Design, Finite Element Method and Testing Method. These
data provided a theoretical basis for the design of the Curved Rake Tine Frame and Headstock.
Optimal Analysis and Application in the Design of Ultra-Light Truss-Core Structures
Authors: Wang Bin , Gu Y. , Guo Hai Cheng , Soh Ai Kah , Fang Dai Ning
Published: March 2009

A novel method for characterizing a high actuating capability light-weight actuator is
described and analyzed. The actuator comprises a truss core and smart face-sheets which result in
bending. The deformation of this beam actuator is obtained by changing voltage inside face-sheets
made from smart material. Materials selections are discussed for practice, and then optimization is
designed to ascertain minimum weight or maximum achievable displacement subject to two types
of constrains. Results show the composite trusses have higher stiffness and strength than metal
trusses. Comparisons with two corrugated core actuators, the truss-core design has better actuating
capability at specified weight.
Study on the Method of Ontological Knowledge Expression of Product Innovative Development and its Application
Authors: Tang Wen Xian , Xia Shou Jun , Jiang Jun Xiang
Published: March 2009

To realize product self-organized evolution innovation that is driven by knowledge, the
method of ontological expression of product innovative knowledge and integrated reasoning
technique are researched. Ontological knowledge system that drives product self-organized evolution
innovation and its expression model were built. The expression manner of ontological knowledge
based on STEP was discussed, and it was implemented by instantiation of ontological knowledge.
The knowledge-based reasoning technique was adopted to transform dada to driven rules, so as to
bring innovative product scheme; the case-based reasoning was used to match corresponding
structure scheme. The knowledge base and rule base for circuit breaker development were set up, and
self-organized evolution innovation of its mechanism system was accomplished. Applied example
shows that ontological expression method of the knowledge and integrated reasoning technique with
maneuverability and practical value can satisfy requirements of self-organized evolution innovation
that is driven by knowledge.
Experimental Study on the Fatigue Properties of RC Beam Strengthened by Prestressed CFL
Authors: Yang Yi , Huang Pei Yan , Deng Jun
Published: March 2009

Bonding prestressed CFL to strengthen reinforced RC structures can improve the bending
capability of structures and the working efficient of CFL. Base on the fatigue experiments of 4 RC
beams strengthened by prestressed CFL, the present paper analyzes the fatigue properties of
prestressed CFL reinforced RC beams. Comparing with the experimental results of strengthened RC
beams without prestress, it can be concluded that the prestressed technology can improve the
reinforcing effect and fatigue lives.
Peculiarity of Accelerated Propagation of Fatigue Crack for Medium Carbon Steel under Variable Amplitude Loading
Authors: Li You Tang , Rui Zhi Yuan , Song Ming
Published: March 2009

Low cyclic fatigue testing of 45 medium carbon steel with the annular V-notch indicates
that the propagation of crack under variable amplitude increase by degrees overloading is faster
than that under constant amplitude overloading. Some problems which include the effect of
constant amplitude overloading to propagation speed of crack, the suitable loading process of
accelerating propagation of fatigue crack, and the fracture figure in suitable loading, should be
discussed. Based on the experimental results and the analysis of the fracture surfaces of the
specimens, the mechanism of propagation of fatigue crack under the overloading is explored. It is
proposed that at the moment of the application of the overloading, the obvious instantaneous
increase of crack growth rates is due to crack blunting. Then an adequate way of loading to make
propagation of crack quickly is found that provide a basis for the engineering application of
extra-low cycle fatigue fracture.
Probabilistic Analysis of Cracked Structures With Uncertainty Parameters
Authors: Ariffin Ahmad Kamal , Akramin M.R.M. , Huzni Syifaul , Abdullah Shahrum , Ghazali Mariyam Jameelah
Published: March 2009

This paper presents a probabilistic approach for fracture mechanics analysis of cracked
structures. The objective of this work is to calculate the rigidity of cracked structures based on failure
probability. The methodology consists of cracked structures modelling, finite element analysis with
adaptive mesh, sampling of cracked structure including uncertainties factors and probabilistic analysis
using Monte Carlo method. Probabilistic analysis represents the priority of proceeding either suitable
to repair the structures or it can be justified that the structures are still in safe condition. Therefore, the
combination of finite element and probabilistic analysis represents the failure probability of the
structures by operating the sampling of cracked structures process. The uncertainty of the crack size
can produce a significant effect on the probability of failure, particularly for the crack size with large
coefficient of variation. The probability of failure caused by uncertainties relates to loads and material
properties of the structure are estimated using Monte Carlo simulation technique. Numerical example
is presented to show that probabilistic analysis based on Monte Carlo simulation provides accurate
estimates of failure probability. The comparisons of simulation result, analytical solution and relevant
numerical results obtained from other previous works shows that the combination of finite element
analysis and probabilistic analysis based on Monte Carlo simulation provides accurate estimation of
failure probability.
Improved Impedance Method and Guided Wave Technique for Damage Assessment of Beam Structures Using PZT Patches
Authors: Hong Yong , Wang Gao Ping , Han Byeong Hee , Hong Dong Pyo , Kim Young Moon
Published: March 2009

Beam structures are a common form in many large structures, and therefore the real-time
condition monitoring and active control of beams will improve the reliability and safety of many
structures. This paper presents a damage assessment method which combines the impedance method
and guided wave method. The combination enabled to improve the damage detection efficiency. The
impedance method is used first to detect whether the damage occurs or not and judge the damage
extent. The guided wave then is introduced to accurately localize damages. The improved method
provides possibility for more accurately identifying and localization damages compared to that
conventional method. A powerful wavelet transform is used to extract the signals efficiently.
Additionally, with using the general function generator to excite the piezoceramic (PZT) patches to
generate the guided wave, the guided wave propagates along with the beam structures with PZT
patches bonded, and the real-time signals are recorded. Damages are indicated by a change of
response signals when compared with a template undamaged condition. The wave attenuation and
mode conversion is sufficient to detect various types of defects. The results show considerable ability
for identifying and localization of the simulated damages.
Residual Strength Analysis of Stiffened Aluminum Panels with Widespread Fatigue Damage
Authors: Li Zhong , Ge Sen , Lv Guo Zhi , Chen Li , Ding Hui Liang
Published: March 2009

Widespread fatigue damage (WFD) is an important concern of aging aircrafts. Residual
strength of stiffened panels with widespread fatigue damage was evaluated by an engineering
approach and a finite element method respectively. Nine stiffened panels with three types of damage
were tested for their residual strength. The predictions are in good agreement with the experiment
results and it is shown the methods could be used in an engineering practice for the residual strength
evaluation with the acceptable accuracy. It can be seen from this research that WFD could result in
significantly reduction in the residual strength of stiffened panels.