bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation on Interface Fracture Behavior of HVAS Coating/Substrate System Based on Weibull Stress Criterion
Authors: Xu Lian Yong , Jing Hong Yang , Han Yong Dian
Published: March 2009

In this paper, the local approach was used to analyze the geometry dependence of coating
specimens for interface brittle fracture initiation, and a definition of the fracture process zone was
proposed in the paper. The results showed that the interface fracture behavior of two types of
specimens with notch had been predicted from the test results of pre-crack specimens based on the
local approach for interface brittle fracture, and the predicted distribution of the critical load for the
notched specimens gave a good agreement with the test results. It indicated that the local approach not
only can be used to describe the interface fracture behavior, but also can be used in the integrity
evaluation for interface between different materials.
Subsonic Interface Crack with Crack Face Contact
Authors: Chen Shao Hua , Xu Guang , Yan Cong
Published: March 2009

A steady-state subsonic interface crack propagating between an elastic solid and a rigid
substrate with crack face contact is studied. Two cases with respective to the contact length are
considered, i.e., semi-infinite and finite crack face contact. Different from a stationary or an open
subsonic interface crack, stress singularity at the crack tip in the present paper is found to be
non-oscillatory. Furthermore, in the semi-infinite contact case, the singularity of the stress field near
the crack tip is less than 1/2. In the finite contact case, no singularity exists near the crack tip, but less
than 1/2 singularity does at the end of the contact zone. In both cases, the singularity depends on the
linear contact coefficient and the crack speed. Asymptotic solutions near the crack tip are given and
analyzed. In order to satisfy the contact conditions, reasonable region of the linear contact coefficient
is found. In addition, the solution predicts a non-zero-energy dissipation rate due to crack face
contact.
Interaction between a Rigid Cylinder with a Piezoelectric Half-Space with Partial Adhesion
Authors: Chen Zuo Rong , Yu Shou Wen
Published: March 2009

An axisymmetric problem of interaction of a rigid rotating flat ended punch with a
transversely isotropic linear piezoelectric half-space is considered. The contact zone consists of an
inner circular adhesion region surrounded by an outer annular slip region with Coulomb friction.
Beyond the contact region, the surface of the piezoelectric half-space is free from load. With the aid
of the Hankel integral transform, this mixed boundary value problem is formulated as a system of
dual integral equations. By solving the dual integral equations, analytical expressions for the
tangential stress and displacement, and normal electric displacement on the surface of the
piezoelectric half-space are obtained. An explicit relationship between the radius of the adhesion
region, the angle of the rotation of the punch, material parameters, and the applied loads is presented.
The obtained results are useful for characterization of piezoelectric materials by micro-indentation
and micro-friction techniques.
Peeling Rate Dependency of Delamination Behavior of Adhesives
Authors: Masuda Ryota , Inoue Hirotsugu , Kishimoto Kikuo
Published: March 2009

Adhesives are widely used in our life and industrial world. However, it is difficult to
characterize their mechanical properties because those strongly depend on environmental and
mechanical conditions such as temperature, humidity or strain rate. In this paper, we focus on the
strain rate dependence of the interfacial strength and investigate the interfacial strength by peel tests
under several peel rates. The results show that, in lower rate region (under 1.0 mm/s), the interfacial
strength is constant and, in transition region (1.0 to 10 mm/s) the interface strength increased with the
peel rate. In middle rate region (10 to 103 mm/s), the interfacial strength is constant again. Over 103
mm/s region, the interfacial strength drops and became lower than those in middle rate cases. From
the observation of peeling front by a high speed video camera, the deformation behavior of adhesives
changes with the peel rate.􀀁Finite element analysis by using cohesive zone model is also conducted,
and influence of the rate dependency of adhesive and base material is discussed.
Hierarchical Adaptive Mesh for FEM Simulations of Ultra High-Speed Impact Problem
Authors: Murotani Kohei , Yagawa Genki
Published: March 2009

We demonstrate how algorithms to compute hierarchical triangular meshes. We can
generate the hierarchical triangular meshes using level-of-detail for the mesh data structure. We
perform hierarchical regional partitions using Ward's method with hierarchical data structure to
achieve the level-of-detail. The meshes using this data structure can be hierarchically compressed
and be unpacked at a faster pace. Additionally, we introduce the adaptive mesh generation
algorithms for the parameters of computational mechanics by setting some kind of metrics in the
level-of-detail.
Experimental and Numerical Study of Cyclic Creep of Cast Magnesium Alloy at High Temperature
Authors: Zeng Xiang Guo , Gao Zhan Hua , Fan Jing Hong , Chen Hua Yan
Published: March 2009

The cast magnesium alloys as AM50 offer a good strength, ductility and surface finish for
automotive industry. But the poor creep resistance limited its application to power components such
as engine and transmission cases at temperatures in excess of 100°C. In order to investigate the cyclic
creep behavior of Magnesium Alloy at high temperature, creep tests of plate specimens AM50 were
conducted in this work. Based on the analysis about the microstructure and defects of AM50 under the
condition of cyclic creep, a cyclic creep constitutive model with isotropic and scalar damage
parameter was developed. Furthermore, the proposed model was experimentally verified by analyzing
the cyclic creep and recovery response of Cast Magnesium alloy under cyclic loading with dwell time.
Comparisons between calculated results and experimental data showed good agreement.
Multiaxial Electromechanical Couple Behavior of Ferroelectric Ceramic PZT53
Authors: Wan Q. , Chen C. , Shen Y.P. , Li Si Zhong , Huang X.C.
Published: March 2009

The multi-axial constitutive behavior of poled and unpoled ferroelectric ceramic PZT53
is measured under different proportional tension-torsion loading and compression-torsion loading
until destroy. Deformation is measured using strain gauges. These results are used to map out
“Switching” and “destroy” surfaces. The two surfaces are found to be a function of the polarization.
Switching surface is similar to Mises and Tresca yield surface. Destroy behavior corresponds to
maximal principal normal stress rule. For poled PZT53, the effect of bias electric field on its
multiaxial behavior has also been exploited.The results indicated that the “Switching” surface
disappear with the increased bias electric. The ultimate goal is to develop an experimentally
validated micromechanics based phenomenological constitutive model for ferroelectric materials.
Growth Characteristic and Fracture Toughness of Laser Rapidly Solidified Al2O3/YAG/ZrO2 Ceramic Eutectic In Situ Composite
Authors: Su Hai Jun , Zhang Jun , Liu Lin , Fu Heng Zhi
Published: March 2009

Directionally solidified oxide ceramic eutectic composites with superior strength,
oxidation resistance, creep resistance, structural stability and low sensitivity to crack at high
temperature have aroused much attention in recent years, and various preparation techniques have
been developed. In situ fabrication of ceramic eutectic composites by laser rapid solidification is a
cheap and quick method compared to conventional multi-step fabrication methods of fiber reinforced
composites for high temperature use. In this paper, Al2O3/YAG/ZrO2 ternary eutectics are rapidly
prepared from melt by directional solidification using laser zone remelting technique, the growth
characteristic and fracture toughness are investigated. The results show that: (1) Laser rapidly
solidified Al2O3/YAG/ZrO2 ceramic eutectic in situ composite presents a fine interpenetrating
network structure, in which Al2O3, YAG and ZrO2 phases are continually interconnected and finely
coupled without pores, colonies and grain boundaries between interfaces. (2) Laser scanning rate and
power density strongly affect the eutectic growth. With the processing parameters adjusted properly,
the eutectic shows homogeneous and coupled lamellar microstructure. The characteristic dimensions
of the microstructure are around 2~3 1m for Al2O3 and YAG phases, and around 0.2~1 1m for ZrO2
phases, respectively. (3) The hardness and fracture toughness of the rapidly solidified
Al2O3/YAG/ZrO2 eutectic are 16.7 GPa and 8.0 MPa.m1/2, respectively.
Strength Behaviour of Polysilicon Thin Film Flexure Hinge
Authors: Zhang Yong Yu , Chen Xiao Yang , Sha Ling
Published: March 2009

This work reports on strength behaviour of polysilicon thin film flexure hinge. In order to
develop a microscopic modelling of thin film flexure hinge for microstructures, in situ test benches
have been designed and fabricated. The experiment demonstrated that a deviation between the
macroscopic theory value and experimental result. A model similar to that used for rotational stiffness
in macroscopic steel is used to fit testing data for polysilicon film flexure hinge. The dynamic
characteristic and fatigue behaviour of the thin film flexure hinge were also investigated. The hinge
was excited by an integrated electro-thermal microactuator that could be self-heated and driven.
Resonant frequency of the polysilicon flexure hinge test benches is 6.5 Hz, and the maximum
operating frequency reached 1KHz. When a cyclic loading of 1μN.μm was exerted to the
micromachining flexure hinge, the limit stress alternation number exceed 1.0×108. When the stress
alternation number exceeded 1.0×109, the polysilicon beam of microactuator would lost its elastic
character. If the micro hinge operated at high temperature (exceed 200/), the lifetime would
decreased. If the working temperature were too high, the micro hinge would be burned out.
Interface Cracking and Particulate Size Effect in Particle-Reinforced Metal-Matrix Composites
Authors: Wei Yue Guang , Li Tie Ping , Xie Hai Ou
Published: March 2009

The mechanical behaviors of the ceramic particle-reinforced metal matrix composites are
modeled based on the conventional theory of mechanism-based strain gradient plasticity presented by
Huang et al. Two cases of interface features with and without the effects of interface cracking will be
analyzed, respectively. Through comparing the result based on the interface cracking model with
experimental result, the effectiveness of the present model can be evaluated. Simultaneously, the
length parameters included in the strain gradient plasticity theory can be obtained.
Regular Fracture Control of Pressed Notch Bar under Three-Point Bending
Authors: Yan Chang Feng , Li You Tang , Jin Wu Yin , Wu Li Xiao , Huang Hua
Published: March 2009

A new method for fabricating crack is introduced by pressing the wedge on bar. The path
of the crack propagation is not regular when the ratio of length and diameter is less than 1.8 on the
symmetrical support. The load of the wedge for pressing the notch is given in this paper. The 2-D
finite element is applied to simulate the crack propagation by the maximum normal stress theory.
The experimental results show that the quality of the fracture section will vary with the span on the
three-point bending. In order to control the crack propagation along the desired section regularly,
the asymmetrical three-point bending is proposed. The simulation results show that when the
difference of the two spans is between 11 and 22 in asymmetrical three-point bending under the
parameters condition, the good quality of the section will be obtained, and the experimental results
also strong support the conclusion.
Numerical Simulation of Different-Shaped Random Aggregates’ Influence on Concrete’s Compression Strength
Authors: Qu Hong Chang , Chen Guo Rong
Published: March 2009

A three-phase composite material specimen consisting of aggregates, mortar matrix and
their bonding material is created through the Monte-Carlo method. The Mazars isotropic damage
evolution model is used to describe the meso-mechanics damage deterioration of concrete. And the
finite element method is adopted to simulate respectively the uniaxial compression numerical
models of two, three and full graded specimens with sphere and polyhedron aggregates. Following
are the conclusions from the test results: the ultimate load capacity of arbitrary polyhedron
aggregate specimen is greater than that of the sphere one of the same grade; the size effect law
exists in these numerical models of concrete specimens; the stiffness of the polyhedron aggregates’
specimen of the same grade is greater than that of the sphere ones’, and the softening curves of the
sphere aggregate model are easier than those of the polyhedron by comparison in the softening
phase of stress-strain curves.
Deformation Analysis of Shape Memory Alloy Using SEM Scanning Moiré Method
Authors: Xie Hui Min , Kishimoto Satoshi , Li Yan Jie , Liu Dao Zhi , Zhang Ming , Hu Zhen Xing
Published: March 2009

In this paper, scanning electron moiré method is used to measure the mechanical behavior
of Ferro-based shape memory alloys(SMA). The moiré patterns are formed by the interference
between a 1000 lines/mm cross-type specimen grating (which is fabricated using electron beam
lithography) and the scanning lines of Scanning Electron Microscope (SEM). When the specimen is
subjected to uniform tension load at the room temperature, the unloading residual strain values in the
different regions under the same tensile load and the values in the same region under different tensile
loads are compared respectively. The shape memory effect is also studied. From the experimental
results, it can be concluded that the proposed moiré method is highly accurate to measure the
mechanical behavior of microscopic field.
Plastic Crushing Behavior of Thin-Walled Spheres
Authors: Xue P. , He J.P. , Li Yu Long
Published: March 2009

Plastic crushing behavior of thin-walled spheres under various loading cases is studied
using Finite Element Method. The entire plastic deformation process is tracked during the
post-buckling process. The results are compared with the experimental results reported in literature
[13], and very good agreements between the numerical simulation and the experimental result are
achieved.
Examination of the Optimal Local Model Size of Structure with a Surface Crack in the 3-D Local Hybrid Method
Authors: Machida Kenji , Ueno Takanori
Published: March 2009

We developed the 3-D local hybrid method to evaluate the 3-D stress field inside the
specimen from displacement data on the free surface obtained from the 2-D intelligent hybrid method.
When a uniform load was applied to the structure with a surface crack, high accuracy was already
acquired in stress analyses. The 3-D local hybrid method was newly applied to structure with a
surface crack which is subjected to bending load. It is expected that the accuracy depends on local
model size. In this study, the width, the thickness and the height of the local model were changed
widely, and analyses were carried out. Then the size of the local model necessary for the analyses was
examined. Assessment of analyses was performed by comparing J integral value of a full model and
the local model.
Hybrid CAD Modeling Theory and Method in Reverse Engineering
Authors: Sun Wen Lei , Zhong Yi Fang , Huang Yan Hua
Published: March 2009

RE is the generic name of a series of technical methods that convert physical parts into
engineering concepts and CAD model. It has been an important branch of modern design
methodology. With the development of computer and graphic design, RE has already no longer met
the simple imitation products, but product innovation based on physical parts. In order to redesign the
CAD model constructed by RE method and then support product innovation, hybrid CAD modeling
method and some related key techniques are studied in this paper. Combining conventional design
and RE, Hybrid CAD modeling method extracts features, constraints, and design intent from
measured data for parametric redesign and eventually completes CAD model.
The Tool Position Generating Algorithm of Intersecting Lines Obtained from Section and Equidistance Surface and Curved Surface Processing
Authors: Jiang Hong , Sun Wen Lei , Huang Yan Hua
Published: March 2009

The algorithm to obtain intersecting lines from section and equidistance surface is one
method of resolving the problem of obtaining NC machining procedure from points cloud data. As far
as cutter paths obtained by section method are concerned, if intersecting lines using tangent plane and
processed curved surface are obtained directly, it will be a quite complicated process and lead to
divergent iteration operation because of inconsiderate design algorithm, and therefore it leads to the
failure of obtaining intersecting lines. So the method of obtaining intersecting lines from section and
equidistance surface is adopted. And this paper put forward and has realized one new algorithm. The
calculation is simple and the algorithm is stable. It avoids the interference of cutting tool paths.
General Post Processing Program for J-Integral Calculation around Arbitrary Shaped Cracks
Authors: Kanto Yasuhiro
Published: March 2009

In this paper, a general post processing program for J-integral calculation is developed to
apply to arbitrary shaped cracks in a three dimensional body. Usually J-integral calculation
programs are options for specific stress analysis programs and they are not applicable to results
from different analysis programs. In most cases, there are many limitations in analysis models
or shapes of cracks. This situation is not favorable for users. This paper will demonstrate a
development of a post-processing program to calculate J-integral for arbitrary shaped cracks in a
three dimensional body. This program requires only discrete data of displacements and stresses at
nodal or numerical integration points. Users can use their own programs for stress analyses and
calculate J-integral after that. In this paper, errors in approximation will be discussed as the first
stage of the development.
The Study of Numerical Stability in the SPH Method
Authors: Xu Fei , Chen Jian She , Huang Qi Qing
Published: March 2009

In this paper, the numerical stability of the SPH method under both tension and
compression conditions are discussed by using one dimensional impact models. The artificial
viscosity and the conservation smoothed approach are tried to suppress both tension and compression
instability. The result clearly shows that the occurrence possibility of tension instability is much larger
than the compression case. The comparison of the controlling techniques of the artificial viscous and
conservation smoothed approach shows that the artificial coefficients are independent on the
numerical instability but can reduce some perturbation, while the conservation smoothed approach
does well for both tension and compression cases. Considering the tension instability directly , a
simple method of inserting particles to avoid the numerical instability is introduced.
The Numerical Simulation of a Bird-Impact on an Aircraft Windshield by Using the SPH Method
Authors: Liu Jun , Li Yu Long , Xu Fei
Published: March 2009

This paper is focused on the development of an effective numerical method to simulate
bird-impact aircraft windshield events. A new Smooth Particle Hydrodynamics (SPH) which has
been incorporated as a solver option into the explicit finite element program PAM-CRASH was
used to model the bird. The deformation between the numerical results and the experimental results
is in good agreement. Simulation results of a bird-impact process indicated that the SPH bird model
is more suitable to model the break-up of the bird into particles. Failure of the windshield in the
experiment was simulated, and the good agreement between the numerical and experiment indicates
that the failure model established in the present paper is reasonable. Finally, the energy changes of
the bird and the windshield were calculated.
Development of Multi-Scale Computation Framework to Investigate the Failure Behavior of the Materials
Authors: Zhuang Zhuo , Liu Zhan Li , You Xiao Chuan , Guo Y.
Published: March 2009

With the development of material science, especially as MEMS/NEMS are playing a
more and more important role in modern engineering, some mechanical behaviors of materials, e.g.,
fracture, shear instability, need to be investigated from multidisciplinary perspective. The molecular
dynamics (MD) simulations are performed on single-crystal copper block under simple shear to
investigate the size and strain rate effects on the mechanical responses of face-centered cubic (fcc)
metals. It is shown that the yield stress decreases with the specimen size and increases with the
strain rate. Based on the theory of dislocation nucleation, a modified power law is proposed to
predict the scaling behavior of fcc metals. In the MD simulations with different strain rates, a
critical strain rate exists for each single-crystal copper block of given size, below which the yield
stress is nearly insensitive to the strain rate. A hyper-surface is therefore formulated to describe the
combined size and strain rate effects on the plastic yield stress of fcc metals.
Numerical Limit Analysis of Two Dimensional Structures by the MLPG Method with Natural Neighbour Interpolation
Authors: Chen Shui Sheng , Liu Ying Hua , Cen Zhang Zhi
Published: March 2009

In most engineering applications, solutions derived from the lower bound theorem of limit
analysis are particularly valuable because they provide a safe estimate of the load that will cause
collapse. In this paper, the lower bound theorem is firstly implemented making use of the meshless
local Petrov-Galerkin (MLPG) method with natural neighbour interpolation. In the present MLPG
formulation, the natural neighbour interpolation is employed for constructing trial functions, while
the three-node triangular FEM shape function is used as the test function over a local sub-domain. The
self-equilibrium stress field is expressed by linear combination of several self-equilibrium stress basis
vectors with parameters to be determined. These self-equilibrium stress basis vectors can be
generated by performing an equilibrium iteration procedure during elasto-plastic incremental
analysis. The Complex method is used to solve these nonlinear programming sub-problems and
determine the maximal load amplifier. The numerical results show that the present solution procedure
for limit analysis is effective and accurate.
Mechanical Properties of Single-Walled Carbon Nanotubes - A Finite Element Approach
Authors: Fan Cheng Wen , Huang Jhih Hua , Hwu Chyan Bin , Liu Yu Yang
Published: March 2009

In this paper, the mechanical properties, such as the axial and radial Young’s moduli, shear
moduli, buckling loads and natural frequencies, of single-walled carbon nanotubes, are estimated by a
finite element approach. Each carbon nanotube is simulated as a frame-like structure and the primary
bonds between two nearest-neighboring atoms are treated as isotropic beam members with a uniform
circular cross-section. In the modeling work, the BEAM4 element in commercial code ANSYS is
selected to simulate the carbon bonds and the atoms are nodes. As to the input parameters of the
BEAM4 element, they are determined via the concept of energy equivalence between molecular
dynamics and structural mechanics, and represented in terms of the force constants of the carbon
bonds found in molecular mechanics. Based on this modeling concept, finite element models of both
armchair and zigzag types of carbon nanotubes with different sizes are established and the mechanical
properties of these tubes are then effectively predicted. Most of the computed results which can be
compared with existing results show good agreement. Moreover, the effects of tube diameter, length
etc., on the mechanical properties are also investigated.
Study of Nanocutting Using Atomic Model
Authors: Chu Chun Yi , Tan Chung Ming , Chiou Yung Chuan
Published: March 2009

The stress induced in a workpiece under nanocutting are analyzed by an atomic-scale
model approach that is based on the energy minimization. Certain aspects of the deformation
evolution during the process of nanocutting are addressed. This method needs less computational
efforts than traditional molecular dynamics (MD) calculations. The simulation results demonstrate
that the microscopic cutting deformation mechanism in the nanocutting process can be regarded as
the instability of the crystalline structure in our atomistic simulations and the surface quality of the
finished workpiece varies with the cutting depth.
Simulation of Fracture of Nanocrystalline Metals
Authors: Yang Fan , Yang Wei
Published: March 2009

A computation sample of nanocrystallion metal with a crack is proposed in this work. The
structural evolution scheme is employed to model the mass flow, the grain boundary cavitation, and
the crack growth of the specimen under remote loading. The scheme leads to a system of ordinary
differential equations that can be solved by Euler integration. The simulation validates the proposal
that the ductile versus brittle transition of nano-grained metals is dictated by the competition of creep
deformation promoted by grain-boundary kinetics, and the decohesion of grain boundaries.
Effects of Surface and In-Layer van der Waals Interaction on Mechanical Properties for Carbon Nanotubes
Authors: Chen Wen Hwa , Cheng Hsien Chie , Liu Yang Lun
Published: March 2009

At the nanoscale, surface effect could cause atomistic structures a pre-stressed or
pre-deformed state, which would consequently have a great dependence on their bulk mechanical
properties. Besides, according to molecular mechanics [1,2], the effect of the non-bonding
interactions among the atoms that are separated by equal or more than two bonds, say, van der
Waals (vdW) forces, should be taken into account. Thus, the underlying objective of the study
attempts to explore the extent of the surface effect and the in-layer vdW interactions on the
mechanical properties of single/multi-walled carbon nanotubes(S/MWCNTs) with two different
types of chiralities, including zigzag and armchair.
To deal with the problem, an atomistic-continuum modeling (ACM) approach is introduced. The
ACM is established by molecular dynamics (MD) simulation and equivalent continuum modeling
(ECM). MD simulation is adopted to derive the initial equilibrium state of CNTs due to the surface
effect, and the ECM is applied to calculate the mechanical properties of CNTs. The ECM is
formulated based on the finite element (FE) approximations, which are composed of
three-dimensional beam elements and one-dimensional non-linear spring elements. They basically
represent the bonding and non-bonding interactions, respectively. The equivalent material constants
of these two types of elements are derived from classical molecular mechanics and beam theory.
The present results are also compared with those obtained from other simulations and experiments.
Green Chemical Treatments for Heating and Cooling Systems
Authors: Drozdz Susan , Hock Vincent F. , Hurt David , Maloney Stephen
Published: March 2009

Scale, corrosion and the and biological growth in industrial water handling processes
result in reduced water flow though pipes, reduced heat transfer, and pump failures. Preventative
treatments for these problems are based upon chemical compounds that are most often toxic and
environmentally persistent. Manufacturers continue to introduce new chemicals and treatment
programs onto the market, and old products have been discontinued. Many manufacturers claim that
the new chemical and treatments are more environmentally friendly and safer for the plant workers
and the users. The U.S. Army Engineer Research and Development Center Construction
Engineering Research Laboratory has undertaken a research effort to look at these new chemical
treatments. The objective of this work was to develop “green” water treatment chemicals that
control biological growth, corrosion and scale while reducing or eliminating the generation of toxic
substances during the manufacture, use, and disposal processes.
The Development of a Corrosion Prognostic Health Management System for Australian Defence Force Aircraft
Authors: Trueman Tony , Trathen Peter , Begbie Kayne , Davidson Len , Hinton Bruce
Published: March 2009

DSTO has been working for more than a decade on the development of tools to monitor the
atmospheric corrosion of military aircraft. Initially, this work involved the development and use of
sensors, both corrosion and environmental. The work has evolved to include corrosion models and
prognostic capabilities to give a more complete corrosion prognostic health management (CPHM)
system. This paper will give a historical perspective of the development of these tools at DSTO and
elsewhere along with their uses and shortcomings. It will also explain how increases in the
understanding of both atmospheric and aircraft corrosion have fed into the development of a more
complete CPHM system.
The current system is being developed by DSTO for the Australian Defence Force (ADF) with a
view to facilitating condition-based maintenance for corrosion prevention that will replace
maintenance dictated by either flying hours or service duration. The system functions by using
sensors to measure the environmental exposure of the aircraft and models to determine the extent of
corrosion expected from this exposure. The CPHM system will give the maintenance engineer a
tool that will enable condition-based maintenance to be achieved and remove the requirement for
costly inspection procedures, especially of hard to access areas. Finally, the work being undertaken
to extend the CPHM system will be discussed.
Simultaneous Reduction of Wear and Corrosion of Titanium, Magnesium and Zirconium Alloys by Surface Plasma Electrolytic Oxidation Treatment
Authors: Nykyforchyn H.M. , Agarwala V.S. , Klapkiv M.D. , Posuvailo V.M.
Published: March 2009

Titanium, magnesium and zirconium alloys are widely used in industrial
applications, which require high wear and corrosion resistance. However current methods of
improving these properties often do not satisfy the requirements of service and functional
properties. An alternative approach is the application of oxide-ceramic coatings using high
temperature process. The coatings are applied by spark discharge plasma in the metal-electrolyte
system at high voltages - PEO (plasma electrolytic oxidation) as an oxide synthesis method. This
method has shown good results for aluminium alloys and with good prospects to be used for
titanium, magnesium and zirconium alloys.
Development of PEO technology to improve the wear and corrosion resistance of titanium,
magnesium and zirconium alloys is discussed in this paper. It describes the methods for obtaining
the required layer-thickness for a specified hardness, porosity, wear and corrosion resistance, sets
up the optimal process parameters (voltage/current) by taking the relation of anodic to cathodic
currents into account, and establishing the electrolyte content of different dopants.
Corrosion Control of Friction Stir Welded Aluminium Airframe Alloy
Authors: Zhou X. , Younes Y. , Wadeson D. , Hashimoto T. , Thompson George E.
Published: March 2009

In the present study, microstructure and its influence on corrosion behaviour of friction
stir welded aluminium airframe alloy have been investigated. Further, the effect of laser surface
treatment on the microstructure and the corrosion behaviour was also assessed. The welded
AA2024 alloy showed the expected zones associated with friction stir welding. Corrosion testing
showed that modified microstructure reduced its corrosion resistance to localized corrosion, with
the regions immediately outside TMAZ being most susceptible to corrosion.
Laser treatment resulted in a melted near-surface layer, up to 5 (m thick, where normal constituent
particles are absent. Scrutiny of the melted near-surface layer revealed continuous segregation
bands, approximately 10 nm thick, containing mainly copper. Corrosion testing showed that laser
treatment increases the short term resistance to localized corrosion due to the removal constituent
particles. However, prolonged testing revealed corrosion within the melted near-surface layer and
delamination of the melted near-surface layer from underlying bulk alloy. The corrosion is
associated with copper rich segregation bands that promote local microgalvanic action.
Graded Anodic Film Morphologies for Sustainable Exploitation of Aluminium Alloys in Aerospace
Authors: Curioni Michele , Skeldon Peter , Thompson George E. , Ferguson John
Published: March 2009

High strength aluminium alloys are widely used in the civil and military aerospace
industry due to their low weight and high mechanical properties, achieved by selected alloying
elements and heat treatments. The resulting multiphase alloy system, a solid solution of alloying
elements in the aluminium matrix and a variety of second phase material, requires specific
anticorrosion measures in order to prevent localized corrosion, which is promoted by microgalvanic
coupling between the different metallographic phases. Traditionally, the anticorrosion performances
are achieved by chromic acid anodizing (CAA), followed by painting. However, environmental
issues and associated costs for the disposal of chromate wastes, require the development of new
approaches for anodizing of aluminium alloys. In this work, the potential for tailoring the porous
anodic film morphology through the film thickness by controlled variations of the anodizing
potential is inspected. The procedure developed is, in principle, applicable to any aluminium alloy
in any anodizing electrolyte and results in the generation of innovative graded porous anodic film
morphologies which promise improvement of anticorrosion properties and replacement of CAA .
Basicity-Gibbs Free Energy Relationships for Binary Alkali Silicates
Authors: Dumitrescu Ovidiu , Radu Dorel
Published: March 2009

In present paper there are presented such correlations for the silica-alkali systems (M2O – SiO2)
where reliable thermodynamic data exists from the thermal equilibrium diagrams. It was observed
that with the saturation of SiO2 tetrahedron with metal ions, the difference in basicity between the
reactants is diminished, in the order SiO2 → disilicate → metasilicate → orthosilicate, and that
confirms the role of driving force for these reactions of the acid-base interaction between oxides
and the intermediate silicates formed. Also, there were proposed some correlations between the
standard formation Gibbs free energy, (Gº298), and basicity percentage, pB, for the binary
compounds from the same oxide systems.
Considering the fact that for a system at equilibrium, reaction constant Kp depends on the
reaction free Gibbs energy (rG0
298) and temperature, a correlation between basicity difference
through basicity percentage, pB, and rG0
298 is proposed.
Structural Role and Distribution of Alkali and Alkaline-Earth Cations in Rare Earth-Rich Aluminoborosilicate Glasses
Authors: Caurant Daniel , Quintas Arnaud , Majérus Odile , Charpentier Thibault , Bardez I.
Published: March 2009

The structure of a seven oxide aluminoborosilicate simplified nuclear glass, bearing a
high amount of neodymium or lanthanum oxide (16 wt%), alkali and alkaline earth cations is
studied. Nd3+ or La3+ are supposed to simulate the trivalent lanthanides and minor actinides present
in nuclear wastes. In the studied glass composition, lanthanide ions have a modifying role and are
located in highly depolymerized regions of the structure as shown by neodymium optical absorption
and EXAFS spectroscopies. Both alkali and alkaline earth cations are present around Nd3+ ions
enabling their stabilization in glass structure near non-bridging oxygen atoms (NBOs). We show
that both the nature of alkali R+ and alkaline earth R'2+ cations and the K = [R'O]/([R2O]+[R'O])
ratio can greatly influence the structure of the aluminoborosilicate glass network. Three glass series
were prepared for which: (i) K ratio was varied from 0 to 0.5 (Na+ and Ca2+ being respectively the
only alkali and alkaline-earth cations), (ii) the nature of R+ cation was varied from Li+ to Cs+ (Ca2+
being the only alkaline earth cation and K = 0.3), (iii) the nature of R'2+ cation was varied from
Mg2+ to Ba2+ (Na+ being the only alkali cation and K = 0.3). 27Al MAS NMR spectroscopy results
show that (AlO4)- units are preferentially charge compensated by alkali cations rather than by
alkaline-earth cations. Both R+ and R’2+ cations can compensate (BO4)- units. Nevertheless, whereas
the proportion N4 of (BO4)- units increases with the size of R'2+ cations, the evolution of N4 with R+
cation size for glasses of the R series is not monotonous. The evolution of sodium ions distribution
trough glass structure is followed by 23Na MAS NMR spectroscopy.
Correlation of Surface Characteristics and Thermal Conductivity of High Silica Glass Fibre Materials
Authors: Setina Janina , Akishins V. , Petersone L.
Published: March 2009

The new generation of high silica materials with high thermal resistance was created by
leaching of chopped glass fibre. These materials with low thermal conductivity are inert to the
majority of chemical reagents, resistant to organic and mineral acids, weak alkali, water and highpressure
steam. High silica chopped strand mats are non-woven fabrics designed for using in a wide
range of insulation and protection applications at temperature till 11000C.
The technology and quality of leaching process of initial Si-Al-Na glass widely depends on
quality of fibre surface characteristics, i.e., roughness of surface of glass filaments. The surface
roughness of the fibre before leaching is a function of chemical durability, therefore it depend on
content of Al2O3.
The thermal conductivity (within 20…10000C) of chopped strand mats directly depends on the
surface roughness.
The morphology and compositional profiles of surface of glass fibre before and after leaching
were investigated using AFM, SEM, X-ray microanalysis and X-ray powder diffractometer.
The different defects for fibre with content of Al2O3 <2.5% and high roughness namely
cracking and crystalline deposits of Na2SO4 on top and into pores of fiber after leaching have been
identified. The presence of sodium ions on surface of fibre decreases the heat insulation properties
of mats.
The structure of glass filaments surface was investigated in order to clarify the influence of
surface characteristics on thermal conductivity of high silica glass fibre non-woven fabrics.
Convolution Models for the Dielectric Function of Glass
Authors: van Nijnatten Peter A.
Published: March 2009

Spectral behaviour of the real and imaginary parts of the optical constants of glass has been
widely investigated to obtain band structural parameters of optically induced transitions. Curve fitting
procedures for obtaining a classical oscillator fit to reflectance and/or transmittance data play an
important role in this application. The present form of the dispersion model that is widely used to
describe disordered media like glass uses a convolution of the Lorentzian oscillator function and the
Gaussian Probability Density Function. This model is capable of describing symmetrical band
shapes only. In this paper a convolution model is proposed based on using the Beta function as PDF.
The maximum of the PDF, which corresponds to the frequency with the highest probability,
corresponds to the central frequency of the particular oscillator species in the convolution model.
For a certain value of the parameter that describes the degree of asymmetry, the new model is
equivalent with the present convolution model and the remaining parameters have an identical
meaning yielding practically identical values. The new model also solves a problem related to the
infinite integration intervals of the Gaussian PDF based convolution model.
Second-Harmonic Generation in Thermally Poled Na2O-Al2O3-TeO2 Glasses
Authors: Ukon Sakiko , Tsujiie Yasuhito , Murai Shunsuke , Fujita Koji , Tanaka Katsuhisa
Published: March 2009

Tellurite glasses exhibit attractive optical properties such as high refractive index, high
transmittance in the infrared-to-visible region, and large third-order nonlinear susceptibility. Poled
tellurite glasses also show second-harmonic generation (SHG) as revealed by the present authors.
However, there exist many unresolved problems in second-harmonic generation of oxide glasses; SH
intensity is low and it decays at room temperature. In this work, the effect of Al2O3 addition on SH
intensity and its decay has been explored for thermally poled sodium tellurite glasses. The decay rate
of SH intensity is reduced by the addition of Al2O3. The result is similar to those reported for
phosphate and silicate glasses containing Al2O3. Also, the glasses poled at a voltage of 4 kV manifest
optimum poling temperature lower than that for the same glasses poled at 3 kV.
Optical Transitions in Chalcogenide Glasses From the Point of View of a Barrier-Cluster Model
Authors: Baník Ivan
Published: March 2009

A barrier-cluster model of chalcogenide glasses is employed to analyze optical transitions
near the absorption edge. The influence of temperature on the optical absorption is studied. The
model is used to explain the temperature shift of exponential tails of the optical absorption and the
temperature dependence of the optical forbidden-band width at low temperatures.
Lead-Free High Refractive Index Glasses Produced from Local Raw Materials
Authors: Dararutana Pisutti , Chetanachan Prukswan , Dutchaneephet J. , Sirikulrat Narin
Published: March 2009

Many difference useful and decorative articles have been made from glasses over the
centuries, especially lead-containing glasses. Due to harmful effects of lead from glass fabrication
process on human beings and considering the health as well as the environmental issues, many
researchers tried to produce leadless glasses using some heavy chemical elements such as barium,
bismuth and zirconium. Nowadays, barium compounds seemed to be satisfactory and to be able to
increase the refractive index. For production of high quality crystal glasses with high refractive
index in Thailand, most raw materials including high quality sand have been imported. Because,
Thailand, in fact, is rich in many kinds of raw materials for glass manufacturing, therefore, this
work is set up to study the fabrication of the lead-free high refractive index glasses using local sand
and barite as the main raw materials. After complete melting, the physical and optical properties of
the prepared glass samples were determined to compare these properties with those of glasses
prepared from foreign sand. It was found that the prepared glasses produced from local raw
materials were suitably for restoration, decoration, radiation shielding, as well as glass jewelry.
These glasses can be considered as one of the environmental friendly materials.
The Influence of the Vitreous Matrix for the Determination of the Lanthanides Doping Concentration from the Optical Transmission Spectra
Authors: Niciu H. , Radu Dorel , Onose C. , Maduta V. , Niciu Daniela , Stroescu H. , Onose C.S.
Published: March 2009

In contrast with transitional metals whose spectra and color depends a lot of the ligands
strength field, the sensitivity of the rare earth spectra is significantly weaker. This is the reason why
the color of these ions is the same whatever the basic vitreous matrix. These properties permit to
establish a relation for the determination of the concentration of these ions in vitreous matrix
directly from the optical transmission spectra. The paper presents some samples of silica and
phosphate glasses with lanthanides content for nonlinear optical applications synthesized at a
laboratory scale. VIS-NIR transmission curves are presented, for several compositions. For the
correlation of the lanthanides content with the specific optical absorption peak one used a method
starting from the Lambert – Beer law. For the Nd2O3 concentration determination, it was used a
method proposed by D.M. Dood and D.B. Fraser for the OH groups content, with an error of +4%.
For specific peaks, expressions for lanthanides concentration in ppm, related to the optical
transmission were found. A possibility appears to directly find the lanthanides concentration from
the absorption coefficient at specific wavelengths for each vitreous matrix. The influence of matrix
is discussed.
Complex Study of E-Glass Corrosion
Authors: Šlemín Pavel , Heide Gerhard , Helebrant Aleš
Published: March 2009

Both the static and dynamic corrosion tests of E-glass were used for different conditions -
temperature, glass surface to solution volume ratio (S/V), solution flow rate (F) and F/S ratio.
Results obtained for glass fibres were compared with the ones for glass grains and planar samples.
Evaluation of experimental results by kinetic model shows that the change of glass surface should
be taken into account in the case of fibres corrosion. The total incongruent process of dissolution
could be explained as congruent dissolution of glass accompanied by back precipitation of SiO2 or
silicates. In most cases, more then 90% of SiO2 precipitates back. The second possible explanation,
i.e. SiO2 network dissolution accompanied by selective leaching of Ca, B and Al, is not very
probable. The glass sample shape can influence the estimation of dissolution rate. Up to now, with
existing kinetic models, the dissolution rates evaluated from experiments with different shapes of
glass (fibres, grains, planar) cannot be used as materials properties.
Liquidus Temperatures of Bioactive Glasses
Authors: Arstila Hanna , Tukiainen Mikko , Taipale Susanne , Kellomäki Minna , Hupa Leena
Published: March 2009

Melts in the composition range of bioactive glasses have their liquidus temperatures
within or close to the working range. Additionally, bioactive glasses show a strong tendency to
crystallization due to their composition. Thus, many bioactive glass compositions are unsuitable for
demanding working procedures such as fiber drawing. In this work we discuss the suitability of
different methods for measuring liquidus temperature of bioactive glasses. Thermal analysis was
used, and complemented by sintering curves as given by hot stage microscopy. Hot stage
microscopy could be used to measure liquidus also when the thermal effect associated with liquidus
was low and consequently the DTA was not suitable. Liquidus of some glasses was measured with
optical microcopy for samples heat treated in a gradient furnace. The values indicating the
crystallization of the samples during viscosity measurement with rotational viscosimeter were
compared with the other measurements. The crystalline phases formed at liquidus were identified
with XRD and SEM-EDXA. The measured liquidus temperatures were also tested by drawing fibers
directly from molten glass and from preforms heated to typical fiber drawing viscosity values. For
all compositions the fiber drawing viscosity values were below liquidus. Continuous fibers could be
manufactured of compositions only with low rates of crystal nucleation and growth.