bluuebunny/crossref_metadata_2025 huggingface dataset:
System Fatigue Damage Reliability Assessment of Railway Riveted Bridges
Authors: Wang Chun Sheng , Xu Yue , Chen Ai Rong , Chen Wei Zhen
Published: March 2009

According to the fatigue damage failure mechanism of riveted members, a riveted member
probabilistic fatigue failure model (RMPFFM) was proposed, and a fracture finite element program is
developed to calculate the geometry function of RMPFFM. Furthermore, a system fatigue damage
reliability model of riveted bridges was proposed, and based on Monte-Carlo method, a large system
fatigue damage reliability analysis program was developed to calculate the system fatigue failure
probability. Then the system evaluation model was used to predicate the system fatigue damage
reliability of Ganjiang Railway Bridge. According to assessment results, the probabilistic remaining
fatigue life, safe inspection intervals and maintenance strategy are determined, which can control and
avoid fatigue failure accident and reduce the contingent disaster in bridge service life.
Assessing the Feasibility of Monitoring the Condition of Historic Tapestries Using Engineering Techniques
Authors: Dulieu-Barton Janice M. , Sahin M. , Lennard F.J. , Eastop D.D. , Chambers A.R.
Published: March 2009

The findings of a year-long programme carried out by a multidisciplinary
engineering/conservation team are described. A mass-produced textile material that can be used to
represent tapestries is identified and mechanical tests are detailed which demonstrate it behaves in a
similar way to tapestry. The feasibility of using optical fibre sensors, full-field optical strain
measurement techniques and thermography for monitoring tapestry degradation is assessed. The
results of preliminary findings are presented and a rationale is developed for in-situ quantitative
strain monitoring of tapestries.
Damage Assessment of Nanostructures
Authors: Pugno Nicola Maria
Published: March 2009

In this paper the damage assessment of nanostructures is discussed. As an example we
assess the damage of nanobeams with non destructive dynamical resonance or destructive tensile
tests: a small number of nanocracks, i.e., ~10, with length of ~1nm, is accordingly estimated.
An Investigation on Damage Detection in Aircrafts Panels Using Nonlinear Time Series Analysis
Authors: Trendafilova Irina , Manoach Emil , Cartmell Matthew P. , Ostachowicz Wiesław M. , Zak Arkadiusz
Published: March 2009

This study investigates a possibility for representing, interpreting and visualising the
vibration response of aircraft panels using time domain measurements. The aircraft panels are
modelled as thin orthotropic plates and their vibration response is simulated using FE modelling.
The vibration response of a thin aluminium panel is simulated using FE modelling. The first ten
resonant frequencies are estimated for the FE model and for the dynamically tested panel. They
were found to show somewhat low sensitivity to damage. Then the simulated vibration response of
the panel is transformed and expanded in a new phase space. This presents an alternative way to
study and analyse the dynamics of a structure. A two dimensional phase space is used in this
investigation. Thus instead of studying the single dimension measured vibration characteristics one
is faced with expanded two dimensional variables which can be visualised and this facilitates the
comparison between the damaged and the non-damage states.
Experimental Modal Analysis for Damage Detection of Buildings via Gabor Transform Technique
Authors: Valente C. , Spina Daniele , Gabriele S.
Published: March 2009

The paper presents the revised formulation of a signal processing methodology aimed at
identifying the dynamics of buildings hit by earthquakes. The methodology is based on the Gabor
joint time-frequency representation and allows to identify an evolutionary modal model whose time
changes are used to evaluate the damage presence and severity. Dynamic tests are performed in
advance to provide reference values and their confidence ranges used for the assessment of the
results. The methodology has been extensively applied to the buildings belonging to the Italian
national network of seismic structural monitoring. A sample application referred to a representative
reinforced concrete buildings is shown.
Advanced Rolling-Element Bearing Diagnostics Based on Cyclic Spectral Analysis
Authors: Antoni Jerome , Boustany Roger
Published: March 2009

Rolling-element bearing vibrations are random cyclostationary, that is they exhibit a
cyclical behaviour of their statistical properties while the machine is operating. This property is so
symptomatic when an incipient fault develops that it can be efficiently exploited for diagnostics.
This paper gives a synthetic but comprehensive discussion about this issue. First, the
cyclostationarity of bearing signals is proved from a simple phenomenological model. Once this
property is established, the question is then addressed of which spectral quantity can adequately
characterise such vibration signals. In this respect, the cyclic coherence - and its multi-dimensional
extension in the case of multi-sensors measurements -- is shown to be twice optimal: first to
evidence the presence of a fault in high levels of background noise, and second to return a relative
measure of its severity. These advantages make it an appealing candidate to be used in adverse
industrial environments. The use and interpretation of the proposed tool are then illustrated on
actual industrial measurements, and a special attention is paid to describe the typical "cyclic spectral
signatures" of inner race, outer race, and rolling-element faults.
Aspects of Novelty Detection
Authors: Worden Keith , Manson Graeme , Surace Cecilia
Published: March 2009

The object of this paper is to illustrate the use of novelty detection techniques in
Structural Health Monitoring (SHM) by the consideration of a number of case studies of varying
complexity, from a simple lumped-mass system to an FE model of an offshore structure to an
experimental study of an aircraft wing.
A Framework for Novelty Detection in Jet Engine Vibration Data
Authors: Clifton David A. , Bannister Peter R. , Tarassenko Lionel
Published: March 2009

A novelty detection approach to condition monitoring of aerospace gas-turbine engines is
presented, providing a consistent framework for on- and off-line analysis, each with differing typical
implementation constraints. On-line techniques are introduced for observing abnormality in engine
behaviour during aircraft flights, and are shown to provide early warning of engine events in
real-time. Off-line techniques within the same analysis framework are shown to allow the tracking of
single engines and fleets of engines from ground-based monitoring stations on a flight-by-flight basis.
Results are validated by comparison to conventional techniques, in application to aerospace engines
and other industrial high-integrity systems.
Structural Health Monitoring Experimental System Implemented in a Turboprop Commercial Aircraft
Authors: Bovio Igor , Lecce Leonardo
Published: March 2009

The purpose of the paper is to present an innovative application within the Non
Destructive Testing field based upon vibration measurements developed by the authors, and already
tested for analysing damage of many structural elements. After having tested this application on
different test articles in laboratory condition, experimental tests have been executed, in
collaboration with the ATR company, on a turboprop ATR-72 aircraft, in order to validate the
technique on a real aeronautical structure. The monitoring system have operated an off-line check
on the structure, during the aircraft ground operations, as if it were a normal maintenance
procedure. The results are reported in the paper.
This proposed new method is based upon the acquisition and comparison of the Frequency
Response Functions (FRFs) of the monitored structure before and after damage occurs. Structural
damage modify the dynamic behaviour of a structure affecting its mass, stiffness and damping, and
consequently the FRFs of a damaged structure, when compared with the FRFs of its sound
configuration, making the identification, localization and quantification of damage possible.
The activities presented in the paper focus mainly on a new FRFs processing technique based upon
the determination of a representative “Damage Index” for identifying and analysing damage.
Furthermore, a dedicated neural network algorithm has been elaborated to develop an automatic
system which recognises positive samples, “healthy” states of the analysed structure, discarding
negative ones, “damaged or perturbed” states of the analysed structure. From an architectural
standpoint, piezoceramic patches have been used as both actuators and sensors.
Effect of Crowning of Dovetail Joints on Turbine Blade Root Damping
Authors: Allara Marco , Zucca Stefano , Gola Muzio M.
Published: March 2009

Stresses due to resonant vibrations induce fatigue damage in turbomachinery blades
jeopardizing their structural integrity. Damping plays a fundamental role in passive control of
resonant stresses. In the present work the effect of ‘crowning’ of dovetail joints on blade-root
friction damping is for the first time investigated. In detail, the damping of a simplified blade is
measured under varying centrifugal load for two different joint geometries: a customary dovetail
attachment and a ‘crowned’ one. A theoretical model is developed to quantify the damping
generated at the contact surfaces. Experimental results and analytical predictions are compared.
The Umberto I Gallery in Naples: The Influence of Corrosion Damage on the Seismic Performance of the Iron Roofing Structure
Authors: Landolfo Raffaele , Di Lorenzo G. , Guerrieri M.R. , Mammana O. , Portioli Francesco
Published: March 2009

This paper is concerned with the results of the vulnerability assessment of the iron
roofing structures of the Umberto I Gallery in Naples. The study is performed considering both the
damage caused by corrosive phenomena and the seismic risk. In particular, the evaluation of the
seismic performance has been carried out by developing a three-dimensional finite element model
of the structure and calculating the thickness loss due to corrosion on the basis of suitable damage
curves.
Experimental and Numerical Modal Identification of the Fossanova Gothic Cathedral
Authors: de Matteis Gianfranco , Langone I. , Colanzi Fabio , Mazzolani Federico M.
Published: March 2009

This paper focuses on the dynamic behaviour of the Fossanova cathedral (Latina,
ITALY), which represents a magnificent example of pre-Gothic style church, whose structural
typology is largely present in the Mediterranean area, especially in many Countries characterised by
a High-Medium seismic hazard. In particular, within the European research project PROHITECH,
aiming at investigating the seismic vulnerability of such a structural typology, experimental and
numerical analyses have been carried out. Firstly, detailed investigations have been devoted to the
identification of the geometry of the main constructional parts as well as of the mechanical features
of the constituting materials of the cathedral. Then, both Ambient Vibration Tests (AVT) and
Numerical Modal Identification analyses by Finite Element Method (FEM) have been applied,
allowing the detection of the main dynamic features. Finally, a refined FEM model reproducing the
dynamic behaviour of the cathedral by using scaled physical quantities according to the
Buckingham theorem has been developed. In fact, the present study has to be intended as a
preliminary activity devoted to se up a shaking table test on a reduced scale physical model of
Fossanova cathedral, which will be shortly carried out at the IZIIS laboratory (Skopje, Macedonia).
Measurement of Acoustic Emission Signals: Influence of the Couplant
Authors: Fasana Alessandro , Garibaldi Luigi
Published: March 2009

The acoustic emission (AE) technique, whose modern roots are found in the early 50’s,
analyses the elastic waves generated into solid materials in a frequency range usually well above the
human ears limit. AE are sound waves emitted when abrupt variations occur in the local distribution
of strain in a medium. These variations are generally associated with, for example, the growth of
fractures, phase transformations and corrosion under various loading conditions. This is why the AE
technique can be applied as a non destructive and passive tool in condition monitoring of structures,
a typical application being the pressure vessels and piping field.
In this paper, after a short summary on wave propagation, the AE is simulated by a pulse generator,
acting on a bar and a plate. The aim is to highlight the effects of the sensors positioning on some of
the parameters frequently adopted to describe the AE activity, e.g. its amplitude and strength.
Sensor Fault Identification Using Autoregressive Models and the Mutual Information Concept
Authors: Kraemer P. , Fritzen Claus Peter
Published: March 2009

This paper presents a combined approach for sensor fault identification looking for
changes within one channel on one hand and for changes between the different channels on the
other hand. The first method is based on the identification of autoregressive (AR) models from the
reference time signals for each sensor channel separately. The reference models are then used for the
prediction of the future sensors signals. The statistical properties of the residuals between this
prediction and the true measurement allow a statement about changes of the sensor signals. The
second method is based on the concept of mutual information between two signals X and Y from
two different sensors. Mutual information or transinformation measures the information about the
channel X that is shared by Y. This requires a certain redundancy of information represented in the
different sensor signals. It can be seen that the mutual information changes as soon as a sensor fault
occurs because the sensor fault information is not present in the other sensor signals.
An Interval Uncertainty Based Method for Damage Identification
Authors: Gabriele S. , Valente C. , Brancaleoni F.
Published: March 2009

The problem of damage identification in presence of uncertainties is faced up in the
framework of interval analysis. A method previously developed by the authors in the context of
model updating and global minimization for dynamic problems is applied to identify the damage in
framed structures. The inclusion property of the interval analysis is exploited to find the bounds of
the physical solutions. Model parameters, experimental measures and modelling errors are
considered as possible sources of uncertainty. The advantages of the interval approach are discussed
through numerical simulations involving the different kind of uncertainties.
Computational Approaches for Good Alternative Solutions Based Load Resistance Capacity in Design of Steel Moment-Resisting Frames
Authors: Choi Byoung Han
Published: March 2009

A modeling technique to generate good design alternatives from optimal design of steel
moment resisting frames is proposed. First presented is the development of Genetic
Algorithm(GA)-based approaches that enable designers to identify the best locations for rigid
connections in a frame. This GA uses a unique cost function that enables the trade-off study
between the number of rigid connections and total cost. Second, the optimization formulation is
modified to generate alternatives with a cost comparable to that of the optimal solution. It enables
engineers to compare different solutions on the basis of the structure’s lateral load resistance
capacity along with incidental factors like the location of the rigid connections, number of different
section types, column splices etc. An example of a 5-story and 5-bay steel moment resisting frame
is provided to illustrate the effectiveness of the proposed study.
Structural Analysis Methods for Structural Health Management of Future Aerospace Vehicles
Authors: Tessler Alexander
Published: March 2009

Two finite-element-based, full-field computational methods and algorithms for use in
Structural Health Management (SHM) systems are reviewed. Their versatility, robustness, and
computational efficiency make them well suited for real-time, large-scale space vehicle, structures,
and habitat applications. The methods may be effectively employed to enable real-time processing
of sensing information, specifically for identifying three-dimensional deformed structural shapes as
well as the internal loads. In addition, they may be used in conjunction with evolutionary algorithms
to design optimally distributed sensors. These computational tools have demonstrated substantial
promise for utilization in future SHM systems.
Damage Localization Based on Power Spectral Density Analysis
Authors: Fang Sheng En , Perera Ricardo , Huerta Maria Consuelo
Published: March 2009

An environmental excitation having random characteristics may be more effective and
cost-efficient than other excitation means for non-destructive damage identification purpose on
most of the large-scale engineering structures under operation. In general, many existing damage
indexes are constructed based on the modal properties derived firstly from the power spectral
density (PSD) analysis of the structures under random excitation. However, the derivation
procedures for the modal parameters usually introduce some extra errors into the indexes. This
paper aims to propose a simple and feasible damage location index (DLI) constructed directly
derived from the analysis results of the structural response PSD. The performance of DLI was
verified using an aluminum beam with fixed ends and an experimental reinforced concrete (RC)
beam under free boundary condition. Our results show that the damage location of the aluminum
beam can be determined via the plot of DLI value by selecting the peaks with the amplitudes
exceeding a predefined threshold value in both single- and multi-damaged scenarios. And the index
may also predict the possible damage zones in the RC beam experimentally tested.
Structural Integrity Monitoring of Composite Pipes
Authors: Constantin Nicolae , Mihai Alexandrina , Găvan Mircea , Sorohan Ştefan , Dumitraşcu Constantin , Anghel Viorel
Published: March 2009

Composite pipes enjoy increasing interest in the sector of petroleum and gas
transportation, due to a number of qualities, concerning especially the corrosion resistance and light
weight, face to the traditional steel pipes. As composite materials are prone to a various range of
defects and damages which can seriously affect their service ability, reliable inspection methods
have to be tested in order to assure the required in service reliability. The paper presents progress
made in applying complementary global/local non-destructive inspection (NDI) methods, such as
Lamb wave method and infrared thermography (IRT) method, to effective structural health (SHM)
monitoring of composite pipes.
Acoustic Techniques for Wind Turbine Blade Monitoring
Authors: Burnham Kenneth , Pierce Gareth
Published: March 2009

The total electrical generation capacity from wind sources in the International Energy
Agency (IEA) Wind Member Countries has increased from 4 GW in 1995 to more than 51 GW in 2005
thus underlining the strategic importance of the resource. In the last year alone the UK increased its
wind generation by 447 MW, an increase of 85% over that for the previous year. In 2004, wind
generation formed just 0.5% of the national electric demand; this contribution is set to rise over the
next few years with some predictions that wind energy will rise to 8% of the total UK demand by 2010.
The rotor blades of a wind turbine system are a significant structural component of the overall system,
and typically account for 30% of lifecycle costs, and contribute 34% to overall system downtime.
Despite their importance, there is currently very little monitoring of the structural integrity of rotor
components, and what does exist is limited. We perceive that especially with the current political and
technological emphasis on offshore installations, there will be an increase in the perceived need for
remote structural monitoring, and there is indeed currently great interest in this area from the wind
turbine industry. This work focuses on the applications of acoustic techniques to assess the integrity of
typical rotor blade structures. Preliminary results discuss the limiting aspects of acoustic based
techniques based on the physics of acoustic wave propagation in typical structural components.
Comparisons between acoustic emission approaches and conventional active ultrasound will be
considered.
Vibration-Based Damage Assessment for Controller Reconfiguration: Application to an Oilpan
Authors: Peeters B. , Kanev Stoyan , Verhaegen Michel , Van der Auweraer H.
Published: March 2009

One of the objectives of the EU research project InMAR (“Intelligent Materials for
Active Noise Reduction”) is to reduce car engine noise by active control. An oilpan of a passenger
car serves as a demonstrator. A concern in the application of active control is that the controlled
system may change during service life (e.g. due to damage), and hence, may degrade the control
performance. This paper presents two vibration-based methods that are able to autonomously detect
damage and yield updated experimental models of the structure. A first approach is based on
(operational) modal analysis. Based on vibration measurements, the modal parameters of the
structure are estimated. The idea is now to automate this process so that, without human
intervention, a representative dynamic model of the structure is always available. A second
approach uses multiple-model estimation in the case when the state-space models have different
state dimensions. To this end, an existing non-interacting multiple-model estimator has been
extended to make it alert to jumps from one model to another. Both techniques (“Automatic Modal
Analysis” and “Alert Autonomous Multiple Model Estimator”) will be applied to experimental
vibration data from an oilpan of a passenger car subjected to damage (loosening of bolts).
Multi-Phased Array for Damage Localisation
Authors: Malinowski Pawel , Wandowski Tomasz , Trendafilova Irina , Ostachowicz Wiesław M.
Published: March 2009

A method for damage localisation has been developed, which is based on the phased
array idea. Four arrays of transducers, instead of only one, are used to perform a beam-forming
procedure. Each array consists of nine transducers placed along a line, which are able to excite and
register elastic waves. The arrays are placed in such a way that the angular difference between them
is 45º and the rotation point is the middle transducer, which is common for all the arrays. The idea
has been tested on a square aluminium plate modelled by the Spectral Finite Element Method.
Two types of damage were considered, namely distributed damage, which was modelled as stiffness
reduction, and cracks, modelled as separation of nodes in selected finite elements. The plate is
excited by a wave packet (5-cycle sine modulated by the Hanning window). The whole array
system is placed in the middle of the plate. Each phase array in the system acts independently and
produces maps of a scanned field based on the beam-forming procedure. These maps are made of
signals that represent the difference between the damaged plate signals and those from the intact
plate. An algorithm was developed to join all four maps. This procedure eliminates the necessity to
analyse each map individually and also gives the possibility to extract common features only. It
allows to remove ambiguity and helps to localise damage more precisely than in the case of a single
map. The problem for damage localisation was investigated and exemplary maps confirming the
effectiveness of the system proposed were obtained. The investigation is based exclusively on
numerical data.
A Multi-Algorithm Procedure for Damage Location and Quantification in the Field of Continuous Static Monitoring of Structures
Authors: Lanata Francesca , Posenato Daniele
Published: March 2009

In recent years, several structures have been equipped with permanent monitoring systems,
able to record the response both in terms of displacements and strains over very long periods of time
and, theoretically, for the entire life of the structure. Despite of the number of applications, very few
studies have been presented focused on the interpretation of the data without the study of a numerical
model of the structure. Since an optimal and unique algorithm cannot be proposed depending on the
variety of applications, the aim of the work is to propose a multi-algorithm methodology as a tool for
detecting and localizing the insurgence of damage or material degradation from the measurements
taken during a continuous static monitoring of civil structures. A method based on Principal
Component Analysis will be proposed in order to compare the responses and detect the insurgence of
anomalous behaviors. The algorithm will be first tested on simulated data deriving from a numerical
benchmark with sensors and different damage scenarios, then the proposed methodology will be
validated on a real structure. In this second application, due to the great number of installed sensors,
the algorithm will be integrated with a preliminary analysis in order to cluster and gather together the
sensors with a comparable behavior and a similar sensitivity to damage.
A New Model for Fatigue Life Distribution of Concrete
Authors: Zhao Dong Fu , Chang Qui Ying , Yang Jian Hui , Song Yu Pu
Published: March 2009

Based on the S-N relationship and statistical property of concrete static strength, a
function of fatigue life of concrete,1 (a − blog N) , is found to follow the normal distribution. Thus
a new probabilistic model of fatigue life distribution of concrete is presented in this paper. The
model connects statistical properties of static strength and fatigue life of concrete together in theory,
so it is of clear physical meaning. An experiment was conducted. The experiment was a part of the
project of The State Natural Science Foundation—Failure Criterion of Plain Concrete Under
Multiaxial Fatigue Loading. 2 χ -test and Kolmogorov-Smirnov test are employed to test the
proposed model. Fuzzy optimization is used to compare the model with lognormal distribution.
2 χ -test, Kolmogorov-Smirnov test and fuzzy optimization are also conducted for test data from
references. The results show that the new model is more flexible to fit test data.
Figure of Merit for Thermoelectric Generation Obtained by Enhanced Transport Properties of [100] Oriented Beta-FeSi2 Film
Authors: Kakemoto Hirofumi , Higuchi Tohru , Shibata Hajime , Wada Satoshi , Tsurumi Takaaki
Published: March 2009

beta-FeSi2 films were prepared on Si(001) substrates by the molecular beam epitaxy method using an Fe source. The crystallographic orientation of beta-FeSi2 films on Si(001) substrates were characterized by using x-ray diffraction. Using scanning electron microscopy, surface morphology and film thickness of an oriented sample were observed and estimated. The mobility of beta-FeS2 films on Si(001) substrates was also characterized by Hall measurement at room temperature. The enhancement of figure of merit was evaluated as the functions of mobility and crystallographic orientation of samples.
Evaluation of Laminated Thin-Film ZnO Varistor by PLD
Authors: Sawa Sayuki , Yoshikado Shinzo
Published: March 2009

Laminar-type thin-film ZnO varistors were fabricated on sintered alumina substrates using visible
light (532nm) pulsed laser deposition (PLD). The structure of the laminar-type thin-film varistor is
Ni / Co-added ZnO / impurity layer / Co-added ZnO / Ni. Many droplets were observed on the
deposited Bi2O3+MnO2 compared with the deposited Co-added ZnO thin film. Moreover, for
droplets on the Bi2O3+MnO2 layer, the content of Mn was higher than that of Bi. The V-I
characteristics of the deposited ZnO+CoCl2 or Bi2O3+MnO2 thin film were ohmic. However, V-I
characteristics of laminar-type thin film including the Bi2O3+MnO2 impurity layer deposited for
30min showed nonlinearity. The non linearity index α was approximately 2 and the varistor voltage
was approximately 1V. Thermal annealing in N2 gas atmosphere at 700°C for 10 min was carried out
to improve the crystallinity of the thin film. After annealing, both the varistor voltage and the current
at which nonlinearity appeared decreased. Moreover, the value of non linearity index α was
approximately 2.8.
Ferroelectric Distortion in Bi4Ti3O12 Studied by Neutron Powder Diffraction
Authors: Noguchi Yuji , Miyayama Masaru
Published: March 2009

Crystal structures of Bi4Ti3O12 ferroelectrics have been investigated by high-temperature neutron powder diffraction study. The ferroelectricity in Bi4Ti3O12 is shown to originate from the in-plane displacement of TiO6 octahedra with respect to heavy Bi ions, and that the off-center Ti displacement in the octahedra plays a minor role. Bond valence analysis shows that the underbonding of Bi with the adjacent oxide ions at the perovskite A site in high-temperature paraelectric state plays an essential role in the ferroelectric phase transition in the Bi4Ti3O12 system.
Microstructure Control of Porous Alumina Film Using Aqueous Sol Containing Trehalose
Authors: Miki Takeshi , Nishizawa Kaori , Suzuki Kazuyuki , Kato Kazumi
Published: March 2009

To fabricate porous and thick alumina films, we prepared an aqueous alumina hydroxide sol containing trehalose. The alumina films were deposited by dip-coating technique on glass substrates and heating at 500 °C. The maximum thickness of the film obtained by one-run dip-coating using the sol containing trehalose was over 1000 nm. The film was an aggregate of alumina particles with a diameter of 20-40 nm and pores were interstices between the particles. The porosity of alumina film can be controlled in the range of 48-65 % by changing trehalose concentration in the dip-coating solution.
Friction and Wear Properties of Aluminum Matrix Composites and its Application
Authors: Ouyang Qiu Bao , Gu H.L. , Wang W.L. , Zhang Di , Zhang Guo Ding
Published: March 2009

Friction and wear properties of aluminum matrix composites are studied, including brake
speed, brake pressure, and surface temperature etc. A conclusion can be drawn that SiC particle
reinforced aluminum matrix composites are of stable friction coefficient, high thermal conductivity,
and excellent wear-resistance. Hubs of motorcycle with brake rings of Al/SiC composites were
manufactured and exhibited an excellent braking performance.
Experimental Investigation on the Electrical and Dynamic Mechanical Properties of PMN/Electrically Conductive Carbon Black/Butyl Composites
Authors: Wang Yan Bing , Huang Zhi Xiong , Qin Yan , Du Ming , Zhang Lian Meng
Published: March 2009

In this paper, a three-phase composite with electrically conductive carbon black (ECCB) and piezoelectric ceramic particles, PMN, embedded into butyl (PMN/ECCB/IIR) was prepared by simple blend and mold-press process. Dynamic mechanical properties with various ECCB loading were tested by dynamic mechanical analysis (DMA). DMA shows that the ECCB loading has remarkable effect on the dynamic mechanical properties of the three-phase composite. The temperature range of loss factor (tanδ) above 0.3 the composite was broadened by almost 100°C and the maximum of loss factor shifts to higher temperature in the testing temperature range respectively with increasing the ECCB loading. The piezoelectric damping theory was used to explain the experimental results. The three-phase composites with proper composition can be used as high damping polymer materials.
The Influence of Mixing Manner on Microstructure and Mechanical Performance of B4CP/2024Al Composites
Authors: Nie Cun Zhu , Gu Jia Jun , Liu Jun Liang , Zhang Di
Published: March 2009

The microstructures and tensile performance of B4C particulate reinforced 2024 Al alloy
matrix composites produced by mechanical alloying and common blending techniques were
investigated. The results showed that mechanical alloying was an effective way to fabricate the
particulate reinforced Al matrix composites over common blending. The samples by different mixing
techniques exhibited a clean and chemical products free interface. Tensile strength and elastic
modulus of the composites was higher than that of the based alloy at the expense of ductility. The
composites by common blending exhibited a more ductile fracture surface in contrast to specimen by
mechanical alloying.
Fabrication and Some Properties of Textured Ceramics by Colloidal Processing in High Magnetic Field
Authors: Sakka Yoshio , Suzuki Tohru , Uchikoshi Tetsuo
Published: March 2009

Recently to improve properties, highly microstructure controlled ceramics such as fine-grained, textured and laminated structures are required. We have demonstrated a new processing of textured ceramics with a feeble magnetic susceptibility by colloidal processing in a high magnetic field and subsequent heating. As colloidal processing, slip casting and electrophoretic deposition (EPD) have been conducted successfully. Colloidal processing is known to be a powerful method for consolidating fine particles with a high density and homogeneous microstructure. The degree of orientation strongly depends on the particle dispersion and some processing factors, such as particle size, applied magnetic field, concentration of the suspension, sintering temperature, etc. Crystalline-textured controlled laminated composites can be fabricated using EPD by varying the angle between the vectors of electric field and magnetic field. Also textured ceramics with complicated structure can be fabricated by reaction sintering. The colloidal processing in a high magnetic field confers several advantages and it is possible for this type of processing to be applied to non-cubic ceramics, such as alumina, titania, zinc oxide, tin oxide, hydroxy apatite, aluminium nitride, silicon carbide, silicon nitride, etc. The textured ceramics showed anisotropic properties depending on the crystal plane.
In Situ Synthesis of Rod-Like Tielite / Alumina Ceramic Composites via Mechanical Activation
Authors: Chen Xiao Hu , Chen Xiao Min , Zhao Huang , Wu Ji Huai
Published: March 2009

The purpose of this paper is to investigate the possibility of rod-like Al2TiO5 / α-Al2O3 composites in situ formation via a mechanical activation process. A QM-ISP-4 Planetary Mill was employed to activate mechanically the mixtures of anatase and corundum in air at room temperature for different times. The milled powder mixtures were pressed into platelets and then sintered in air at 1300°C for 3 h. The XRD results showed that only Al2TiO5 and α-Al2O3 phases could be detected in the sintered samples when the activated time reached 30 hours. The SEM observations illustrated the unusual microstructure of Al2TiO5 / α-Al2O3 ceramic composite materials. Abnormal grains with longitudinal length ~10 μm23 transversal length ~1 μm and equiaxed matrix grains of ~3 μm on an average were observed. EDXA proved that the rod-like grains and the fine equiaxed matrix grains were composed of Al2TiO5 and α-Al2O3, separately. The roles of anisotropic grain growth caused by mechanical activation are discussed for the in situ formation of rod-like Al2TiO5 / α-Al2O3 ceramic composite materials.
Formation and Sintering Mechanisms of Reaction Bonded Silicon Carbide-Boron Carbide Composites
Authors: Chen Zheng Fei , Su Y.C. , Cheng Yi Bing
Published: March 2009

Reaction sintering of boron carbide represents an attractive densification process. In this
work, sintering mechanisms of silicon carbide and boron carbide composites were studied. Mixed
boron carbide/graphite mixtures were sintered in a vacuumed graphite furnace between 1380 and
1450oC. The samples were in contact with bulk silicon metal which melts at 1410oC. Reaction
sequence of the composition was investigated by X-ray diffraction, SEM and TEM. It was found
that a reaction between molten silicon and B4C occurred and the reaction produced silicon carbide
and silicon-containing boron carbide. Dense composites can be achieved by pressureless sintering at
1450oC and the final microstructure consists of silicon carbide, boron carbide, silicon-containing
boron carbide and residual silicon at grain boundaries.
Ru-C Nano-Composite Films Prepared by PECVD as an Electrode for an Oxygen Sensor
Authors: Sakata Masato , Kimura Teiichi , Goto Takashi
Published: March 2009

Ruthenium-Carbon (Ru-C) nano-composite films were prepared by microwave-induced plasma-enhanced chemical vapor deposition (PECVD) and the effects of deposition conditions on the microstructure and electrical properties were investigated. The films consisted of agglomerated grains of 10 to 20 nm in diameter, in which Ru particles of 2.5 to 3.5 nm in diameter were dispersed in an amorphous C matrix. The C contents of the films ranged from 86 to 94 vol%. The electrical properties of Ru-C nano-composite films as a catalytic electrode for an yttria-stabilized zirconia (YSZ) solid electrolyte were evaluated by AC impedance spectroscopy. The electrical conductivity at the Ru-C/YSZ interface (σi) was 0.2 × 10-3 Sm-1 at 500 K and increased with increasing temperature. The activation energy of the σi was 70 kJ/mol. Electro-motive-force (EMF) values of an oxygen concentration cell constructed from YSZ electrolyte and Ru-C nano-composite electrodes responded to the change of oxygen partial pressure above 473 K. The response time of the concentration cell was less than 10 s above 573 K.
Monte Carlo Simulation of Porous Layers Sintering
Authors: Neizvestny I.G. , Shwartz Natasha L. , Yanovitskaya Z.Sh. , Zverev A.V.
Published: March 2009

Kinetics of porous layer evolution during high-temperature annealing was investigated by Monte Carlo simulation. Sintering process of spongy one-component films with randomly distributed pores was studied. Layers with porosity from 20% to 50% with simple cubic and diamond-like lattices were under examination. Sintering rate was demonstrated to be non-monotone in time for any film porosity and different lattice coordination number. Metastable states of the system, dependent on time and temperature of annealing process, were revealed. Estimation of annealing time necessary to reach the definite sintering level under changes of annealing temperature was suggested.
Preparation of Mesoporous Silicon Carbide
Authors: Fukushima Manabu , Zhou You , Yoshizawa Yuichi , Miyazaki Hiroyuki , Hirao Kiyoshi
Published: March 2009

Mesoporous silicon carbide with and without SiC filler was prepared from the pyrolysis of
polycarbosilane (PCS), and the relationship between pyrolysis and properties of micro/meso pores was
investigated. The surface area of pyrolyzed PCS without filler significantly decreased from 268 to 0.5m2/g with
increasing pyrolysis temperature, and disappearance of the micropores was observed. In contrast, the pyrolyzed
PCS with filler showed the retention of micro/mesopores, regardless of pyrolysis temperature. In addition, high
surface area ranging from 120 to 180m2/g and a bimodal pore distribution were observed in pyrolyzed PCS with
filler. FT-IR showed the decomposition of Si-H, Si-CH3 and Si-CH2-Si in the PCS network during pyrolysis,
which led to the evolution of hydrogen and methane gas. However, the obtained pores might be larger than the
size of evolved gases. Thus, though micro/meso pores and large surface area were retained by the addition of
filler, coalescence between pores could occur during pyrolysis.
Dynamic Analysis and Three-Dimensional Finite Element Simulation of Cracked Gear
Authors: Shao Ren Ping , Huang Xin Na , Jia Pu Rong , Guo Wan Lin , Hirota Kaoru
Published: March 2009

A method of damage detection and fault diagnosis for gears is presented based on the
theory of elastomeric dynamics according to the theory of cracked beam. It takes an advantage of
accurate fault diagnosis of gear body using the change of dynamic features and has some
advantages for dynamic design of gear systems.The dynamics characteristics, i.e., natural frequency,
vibration shape,dynamic response and so on, due to crack of gear tooth are studied, and the gear
dynamics characteristics caused by the position and size of crack are deeply investigated by
comparison with FEM. The theoretical analysis results are contrasted with numerical simulation
results and shows good agreement with the result by FEM. The proposed method can be used to
detect damage and diagnose fault for gear structures and also can be applied to designing dynamic
characteristics for gear systems.
Application of Percolation Theory to Rock Damage and Fracture
Authors: Yu Qi Wu Peng shao , He Yong Nian , Zhou Li Fen , Zhang Qing Feng
Published: March 2009

Rock is a kind of complex and high-disordered geological material, its damage and fracture
process usually shows obvious criticality. In this paper, percolation theory is applied to analyze and
describe this critical property. First, we discuss the critical fracture probability of rock through
percolation and renormalization analysis, and present the equivalence between fracture probability
and damage variable. Based on scaling law and the relationship between critical exponents, a critical
fractal dimension is obtained. Furthermore, according to the analysis of relationship between damage
and fractal dimension, we suggest a damage-fractal formula, ω=ω0+ (D-D0)/Dc. This formula can not
only be used to describe the damage evolution through the variation of fractal dimension, but also to
define initial damage in rock. Finally, the theoretical conclusions are validated by a series of model
experiments, and the experimental results agree with that of theoretical.
Failure Mechanism and Mechanical Characteristics of Rockmass Containing Close Intermittent Joints under Plane Stress Condition
Authors: Ren Wei Zhong , Chen Hao , Wang Yong Gang , Chen Feng
Published: March 2009

Biaxial compression model tests on rockmass containing intermittent joints under plane
stress condition were carried out in this study, where the laser speckle photo technique was used for
measuring the displacement field. The results obtained have indicated that the laser speckle method
was effective and the measuring value was about 14% less than the measuring value of dial gauges.
Based on the displacement field and the principal stress field which were measured by laser speckle
photo technique, dial gauges and strain gauges, the angle of wing incipient crack, the evolution of
stress field at the joint tip and the path of crack extension were deeply studied. The deformation and
failure characteristics, including the fracture mechanism of rockmass, were also analyzed in this
study.
On Probabilistic Fatigue Crack Growth Behavior under Constant Amplitude Loads
Authors: Kim Seon Jin , Kong Yu Sik , Kim Young Soo , Kim Byung Tak , Noh Young Join , Ku H.K. , Jeong H.C.
Published: March 2009

In this paper, an analysis of fatigue crack growth (FCG) behavior from a statistical point of
view has been carried out. Fatigue crack growth tests were conducted on sixteen pre-cracked compact
tension (CT) specimens of the pressure vessel (SPV50) steel in controlled identical load and
environmental conditions. The assessment of the statistical distribution of fatigue crack growth
experimental data obtained from SPV50 steel was studied and also the correlation of the parameter C
and m in the Paris-Erdogan law was discussed. The probability distribution function of FCG life and
FCG rate seems to follow the 3-parameter Weibull.
Microstructure and Hardness Performance of a SiCp/Al Composite by Pressureless Infiltration Technique
Authors: Zhang Qiang , Han Jie Cai , Zhu Ye , Wu Gaohui
Published: March 2009

In the present work, a SiCp/Al composite was fabricated by pressureless infiltration of
aluminum alloy into loose-packed SiC particles preform, and its microstructure and hardness
performance were investigated. The results showed that the composite was fully infiltrated and the
particles were distributed uniformly in the composite. Interfacial reactions were found in the as-cast
composite and the reaction product was identified as MgAl2O4 by TEM observation and XRD
analysis. The interfacial reactions enhanced the wettability and promote the spontaneous infiltration
process. The thermal exposure process increased the Brinell hardness of the composite. After the
thermal exposure process, the block-like interfacial reaction products were distributed discretely, but
the amount of the reaction products was increased.
Effect of Heat-Treatment on the Mechanical Properties of TiB2P/2024Al Composite
Authors: Jiang Long Tao , Zhao Min , Fan Rui Jun , Xu Shao Lei , Zhu De Zhi , Chen Guo Qin , Xiu Zi Yang , Wu Gaohui
Published: March 2009

55vol% TiB2P/2024Al composite was fabricated by squeeze casting technology, and the
effect of heat treatment on mechanical properties of the composites was studied by means of hardness
measurement, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and
tensile testing etc. Results show that heat treatment has remarkable influence on the hardness and the
tensile strength of the composites. For TiB2P/2024Al composites, the composites aged at 130°C for 5h
can obtain the highest hardness, and the composites peak-aged at 160°C and aged at 190°C for 24h
can obtain the higher tensile strength, which is due to the type of precipitates in the composites.
Considering the experimental error, heat treatments has no obvious effect on elastic modulus of the
experimental composite.
A Study on Fatigue Behavior of SM490A Steel under Low Temperature
Authors: Kang Ki Weon , Goo Byeong Choon , Kim J.H. , Kim Heung Seob , Kim Jung Kyu
Published: March 2009

This paper deals with the fatigue behavior and its statistical properties of SM490A steel
at various temperatures, which is utilized in the railway vehicle. For these goals, the tensile ad
fatigue tests were performed by using a servo-hydraulic fatigue testing machine at three
temperatures: +20°C, -10°C and -40°C. The static strength and fatigue limits of SM490A steel were
increased with decreasing of test temperature. The probabilistic properties of fatigue behavior are
investigated by means of probabilistic stress-life (P-S-N) curve and they are well in conformance
with the experimental results regardless of temperature. Also, based on P-S-N curves, the variation
of fatigue life is investigated and as the temperature decreases, the variation of fatigue life increases
moderately.
Mechanical Properties of (Al2O3+Ni) and (Al2O3+Ni)/Ni Laminated Materials
Authors: Zuo Kai Hui , Jiang Dong Liang , Lin Qing Ling , Zeng Yu Ping , Chen Zhong Ming
Published: March 2009

(Al2O3+Ni) and (Al2O3+Ni)/Ni laminated materials were prepared by tape casting and hot
pressing sintering. The mechanical properties of (Al2O3+20wt%Ni) laminated composites were
higher than those of (Al2O3+50wt%Ni) composites and Al2O3 sample. The strengthening in the
(Al2O3+Ni) composites mainly results from microstructure refinement of the alumina grain size,
cracks bridging and crack deflection by the Ni particles. Results showed that the strength and
fracture toughness of (Al2O3+Ni)/Ni laminated materials were higher than those of Al2O3/Ni
laminated materials with the same layer numbers and thickness ratio. The good mechanical
properties of (Al2O3+Ni) and (Al2O3+Ni)/Ni laminated materials result from the second phase of Ni
particles in Al2O3 layers.
Study on Process Parameters of Multi-Factor Coupling Fields CVI
Authors: Zhang Ming Yu , Huang Qi Zhong , Su Zhe An , Xie Zhi Yong , Huang Bo Yun
Published: March 2009

The C/C composite was rapidly fabricated by Multi-factor coupling fields CVI in a
home-made reactor with propylene as carbon source and carbon felt as porous preform. The effect
of the temperature and pressure on microstructure and properties of the C/C composites was
investigated. Microstructure and morphology of the C/C composites were characterized with optical
microscopy, SEM, XRD and Raman spectroscopy. The results show the C/C composite has rough
laminar pyrolytic carbon and higher density at conditions of 650°C and 12kPa in 12h. The observed
regenerative cones were formed by amplified layers on defects. A new type of pyrocarbon was
observed with graphitization degree 77.9% and crystallite size 30.5 nm and Optical and SEM
morphologies reveal its peculiar structure. It is called “dot structure” pyrocarbon and its formation
mechanism is simple proposed.