bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Concept for Assessing System Reliability Based on Probability Decomposition Method
Authors: Pei Yang , Song Bi Feng , Han Qing
Published: March 2009

In fault tree analysis, the system failure probability and the component importance
measures cannot totally include the contribution of all the component existing states to system
reliability. It is for this reason that an ‘equivalent’ failure probability concept is proposed. First, the
system existing states are analyzed by probability decomposition method. Then Markov chain method
and the expectation theory are used to calculate the expected working number resulting in system
failure. And the system equivalent failure probability is finally attained. Analysis shows that: (1)
equivalent failure probability not only includes the contribution of critical states of component to
system reliability, but also the non-critical states of component are considered; and (2) it may provide
a thorough assessment of system reliability and is useful for reliability design.
Study on the Mechanical Bend Fatigue of Micro-Joining Soldered Joint with Lead-Free Solder
Authors: Qi Fang Juan , Huo Li Xing , Ding Ya Ping , Ding Zhan Lai
Published: March 2009

In recent years, several electronics manufacturers have been working toward introducing
lead-free solder and halogen-free print circuit boards (PCBs) into their products. The key drivers for
the change in materials have been the impending environmental legislations, particularly in Europe
and Japan as well as the market appeal of ‘green’ products. The reliability of the new materials is an
important determinant of the pace of adoption. Fairly extensive mechanical fatigue reliability data is
also available for micro-joining soldered joint such as Ball Grid Array (BGA) with tin-lead solder.
However, similar data is not available for BGAs assembled with lead-free solder. Mechanical
reliability is a critical indicator for phone and BGA survival during repeated keypress, and to some
extent during drop. In this paper, the mechanical bend fatigue of BGAs with tin-lead and lead-free
solders on halogen-free substrates are examined respectively. A tin-silver-copper alloy was used as
lead-free solder due to its increasing acceptance, and the results were compared to those from samples
assembled with Sn63Pb37 solder. The reliability was examined at both low cycle and high cycle
fatigue. Results show that the mechanical bend fatigue reliability of BGA assemblies with lead-free
solder is higher than that of BGA assembly with tin-lead solder. Cross section and failure analysis
indicated two distinct failure modes - solder joint and PCB failure. A 3-D parametric finite element
model was developed to correlate the local PCB strains and solder joint plastic strains with the fatigue
life of the assembly. The intermetallic compoumd (IMC) of micro-joining joint interface was
analysised in the future in order to study on the effect of IMC on the reliability.
Corrosion Behavior of Thixoformed AZ91D Magnesium Alloy in NaCl Aqueous Solution
Authors: Xu Wei Jun , Ma Ying , Chen Ti Jun , Hao Yuan
Published: March 2009

The corrosion behaviors of thixoformed AZ91D alloy immersed in 3.5% NaCl aqueous
were studied by using the weight lose method and observed by scanning electron microscopy and
analyzed by electron probe micro-analysis.The results showed that corrosion rate of thixoformed
AZ91D alloy was higher in initial stages and decreased as the immersion time increased. Compared
with the thixoformed alloy, the change of corrosion rate of permanent mould cast (PMC) alloy was
smoothly. The observation on the corrosion surfaces showed that the primary αphase spherical
particles were first suffered from corrosion during corrosion testing, and then the eutecticαgrains.
the composition of primaryαphase particles in the thixoformed alloy was quite uniform, and thus the
protective film of the corrosion products on the alloy surface was more intact. The amount of the
eutectic β phase in the inter-particle eutectics was relatively higher and the distribution was more
uniform, so the protective film consisted by eutectic β phase was also more intact. That is to say the
protective role from the surface film on the thixoformed alloy was better than that on the PMC alloy
which was the cause of lower corrosion rate of the thixoformed AZ91D alloy.
Status Monitoring and Fault Diagnosis Network System Based on UPnP
Authors: Li Pei Yu , Tan Da Peng , Zhou Tao Qing , Lin Bo Yu
Published: March 2009

Aiming at some problems in the fields of industry monitoring technology (IMT) such as
bad dynamic ability and poor versatility, this paper brought forward a kind of intelligent Status
monitoring and Fault diagnosis Network System (SFNS) based on UPnP-Universal Plug and Play.
The model for fault diagnosis network system was established according to characteristics and
requirements of IMT network, and system network architecture was designed and realized by UPnP.
Using embedded system technology, real-time data collection node, monitoring center node and data
storage server were designed, and that supplies powerful real-time data support for SFNS. Industry
fields experiments proved that this system can realize self recognition, seamless linkage and other self
adapting ability, and can break through the limitation of real IP address to achieve real-time remote
monitoring on line.
Heat-Aging Effect on the Material Properties and Useful Life Prediction of Rubber Materials
Authors: Woo Chang Su , Choi Sung Seen
Published: March 2009

Rubber material properties and useful life evaluation are very important in design
procedure to assure the safety and reliability of the rubber components. In this paper, the heat aging
effects on the material properties and useful life prediction of rubber material for refrigerator
component were experimentally investigated. The accelerated heat aging tests were carried out to
predict the useful life of NBR and EPDM, which is used in refrigerator component. Compression set
results changes as the threshold are used for assessment of the useful life and time to threshold value
were plotted against reciprocal of absolute temperature to give the Arrhenius plot. By using the
compression set test, several useful life prediction equations for rubber material were proposed.
Evaluation of Drop Impact Load for Thin Cone-Shaped Structures
Authors: Omori Takahiro , Inoue Hirotsugu , Kawamura Noriyasu , Mukai Minoru , Kishimoto Kikuo , Kawakami Takashi
Published: March 2009

A method to predict impact load caused by drop impact of thin cone-shaped structures is
investigated. The Hertzian contact theory and the spherical shell theory are applied for modeling the
contact stiffness of the impact tip of the cone. Experiments and finite element simulations are
performed for several cones to evaluate the accuracy of impact load prediction. It is shown that
appropriate choice of contact stiffness model depending on the curvature and thickness of impact tip
of the cone is necessary in order to predict the impact load accurately.
Impact Analysis for the Egg-Crate Structure of a Nuclear Fuel Assembly by Using FEM
Authors: Song Kee Nam , Lee Sang Hoon , Kim Jae Yong
Published: March 2009

A spacer grid assembly is one of the main structural components of the nuclear fuel
assembly of a Pressurized light Water Reactor (PWR). The spacer grid assembly supports and
aligns the fuel rods, guides the fuel assemblies past each other during a handling and, if needed,
sustains lateral seismic loads. The ability of a spacer grid assembly to resist these lateral loads is
usually characterized in terms of its dynamic and static crush strengths, which are acquired from
tests. In this study, a finite element analysis on the dynamic crush strength of spacer grid assembly
specimens is carried out. Comparisons show that the analysis results are in good agreement with the
test results within an 8 % difference range. Therefore, we could predict the crush strength of a
spacer grid assembly in advance, before performing the dynamic buckling test. And also a
parametric study on the crush strength of a spacer grid assembly is carried out by adjusting the weld
penetration depth for a sub-sized spacer grid, which also shows a good agreement between the test
and analysis results.
Fracture Characteristics of a Hybrid Composite Joint Beam for the Tilting Car Body under Static and Fatigue Transverse Loads
Authors: Jung Dal Woo , Choi Nak Sam
Published: March 2009

Fatigue fracture behavior of a hybrid joint beam for the tilting car body was evaluated in
comparison to the case of static fracture. Specimen beams of the hybrid joint part attached in the
real tilting car body were fabricated for the bending test. Characteristic fracture behaviors of hybrid
joint beam specimens under cyclic transverse loads were very different from the case under static
loads. Static transverse load caused shear deformation and fracture in the honeycomb core region,
while cyclic transverse load brought about delamination along the interface between composite skin
and honeycomb core layers as well as fracture of the welded joint. Fracture characteristics obtained
by the transverse fatigue tests were reflected for improving the hybrid joint structure in the real
tilting car body.
Prediction of Cutting Chatter Based on Hidden Markov Model
Authors: Yao Zhe He , Li Xin , Chen Zi Chen
Published: March 2009

Self-chatter is a serious problem in cutting process. This paper aims to solve the problem by
establishing time series model of vibration acceleration signal in cutting process based on Hidden
Markov Model (HMM) technology and achieve the purpose of chatter recognition and prediction.
Features which can indicate cutting state are extracted from the acceleration signal. HMM parameters
are obtained by model training, and the reference models database is built. Then cutting state
recognition is performed according to the feature matching level. Simulations and experiments are
conducted, and the results show that the proposed method is feasible and it could get high recognition
Structural Strength Evaluation of a Carbody by Finite Element Analysis and Load Test
Authors: Yoon Sung Cheol , Jeon Chang Sung , Kim Jeong Guk
Published: March 2009

This paper describes a carbody structural analysis and the result of its loading test. The
purpose of this study is to evaluate the safety and functionality of the body structure operating under
maximum load. Aluminum alloy was used as the body structure’s material. The body structure
consisted of side frame, under frame, roof frame, and end frame. Of these components, the side
frame and under frame were the most important components considering the vehicle and passenger
loads. Both structural analysis and loading test were performed under the condition based on
"Performance Test Standard for Electrical Multiple Unit" with the reference code JIS E 7105. The
test results showed that the body structure is safe and stable under the condition of designed load.
Calculation of Dynamic Parameters of Elastic Thin Plates under Blast Loading
Authors: Fu Yue Sheng , Zhang Qing Ming
Published: March 2009

With elastic theory and approximate calculation, the dynamic responses of elastic thin
plates with four edges simply supported under blast loading is analyzed in this paper , with
dimensional analysis , 30 cases are calculated, and a reasonable model of engineering calculation
is built up in the end.
Application of the Rubber Panel Structure for Railway Crossings
Authors: Yoon Sung Cheol , Chang Sang Hoon , Kim Jeong Guk
Published: March 2009

As the public application of the railway and the road increases, properly functioning and
safe railway crossing between two means of transportation becomes more important. In the past,
materials such as wood, asphalt, and steel were used for railway crossing panel. As these materials
showed various drawbacks, the rubber panel was introduced for railway crossing panel. To
encourage the use of the rubber panel, the structural action analyses of rubber panel were studied.
In this research, using the finite-element method (FEM), several structural properties were analyzed
and presented including the eigenvalue, stress, and displacement by a passing truck’s weight, and
the thermal stress induced by the railway track.
Fatigue Assessment for Ship Structure Acted on Non-Linear Wave Loads
Authors: Chen Chao He
Published: March 2009

Efficient methods are described here to predict the fatigue damage of ship structure due
to nonlinear wave loads that are produced in random seas. Firstly the effects of the non-linear waveinduced
bending moment on the fatigue damage of ship structure with very large bow flare are
presented in short-term prediction by the method of spectrum analysis. Then, the fatigue damage is
estimated and analyzed in the given environment of long-term.
Structural Analysis of Boom System in 42m Aerial Platform Truck
Authors: Hong Yong , Han Su Hyun , Lee Jae Jung , Hong Dong Pyo , Kim Young Moon
Published: March 2009

In the study, the development of aerial platform truck of 42m boom system has been
completed to be satisfied with working in much higher place. To avoid the rollover accident of
vehicles while working, 3D FEA is applied to verify the 3D design, stress concentration, stress
distribution, deflection, natural frequencies etc. In these analyses, traction load of Boom System,
700 Kg and traction degree analyzed to 0° ~ 85°. Analysis result, when Boom System's angle is 0°,
could know that stress concentration and deflection are obtained to maximum. We could predict that
maximum point of Stress concentration is 3.275 as safety factor and deflection of Boom system end
part is max. 78.5Cm. Also could know that natural frequency and mode shape of boom system are
stable in correlation with aerial platform truck's operation area. With these results, the structural
stability of boom system in 42m aerial platform truck is obtained, then finally trying to find an
optimum design of aerial platform truck.
Development of a Material Mixing Method for Topology Optimization of a Structure with Multiple Thermal Criteria
Authors: Han Seok Young , Kim M.S. , Choi S.H. , Park J.Y. , Yi Byung Ju
Published: March 2009

A material mixing method to obtain an optimal topology for a structure in a thermal
environment was suggested. This method is based on Evolutionary Structural Optimization (ESO).
The proposed material mixing method extends the ESO method to a mixing several materials for a
structure in the multicriteria optimization of thermal flux and thermal stress. To do this, the
multiobjective optimization technique was implemented. The overall efficiency of material usage
was measured in terms of the combination of thermal stress levels and heat flux densities by using a
combination strategy with weighting factors. Optimal topologies having multiple thermal criteria
for a printed circuit board (PCB) substrate were presented to illustrate validity of the suggested
material mixing method. It was found that the suggested method works very well for the
multicriteria topology optimization.
Optimization of Materials and Modal Analysis for Motorcycle Frame
Authors: Ma Ming Tu , Xiang Xiao Feng , Li Zhi Gang , Yi Hong Liang , Bai Hong Wu , Zhang Hao
Published: March 2009

The FEM was used to analyze the stress distribution of a motorcycle frame on the condition
of normal running, starting up, turning and braking, respectively. Having been carrying on the
2000km of running test, the initial design motorcycle frame was found several cracks or fractures in
the bending points of the square tube and in the welding seam, whose reasons were analyzed then. The
metallographical structures of materials and crack parts of the frame were observed and analyzed and
Q235. Based on the results mentioned above, the Q345 steel(Chinese steel mark) was used to replace
the Q195 steel in the bending square tube and the prop of the steering column. And the welding and
manufacture processes were optimized and improved. Finally, the motorcycle frame whose materials
had been optimized could keep running in good condition and satisfy the demands after 16000km of
running test.
Degradation and Failure Mechanisms of EPDM Rubbers for Automotive Radiator Hoses
Authors: Kwak Seung Bum , Choi Nak Sam
Published: March 2009

Coolant rubber hoses for automobile radiators under thermal and mechanical loadings can
be degraded and thus failed due to the influences of contacting stresses of air, coolant liquid and to the
locally formed electricity. In this study, degradation behavior of the radiator hose made of EPDM
rubber was evaluated. The thermo-oxidative aging test showed that the surface hardness IRHD of the
rubber increased together with a reduction of failure strain. By the electro-chemical test it was shown
that the penetration of coolant liquid into the skin of the rubber hose arose inducing an increase in
weight of specimens as well as a decrease in failure strain and IRHD hardness. The penetration of
coolant liquid altered considerably the micro-structure and the micro-hardness distribution along the
depth in the rubber hose. On the basis of the above results failure mechanisms of degraded EPDM
rubbers were suggested according to the kinds of contacting stresses.
Shear-Type Fatigue Crack Growth in SAE52100 Steel
Authors: Cho Daisuke , Matsunaga Hisao , Endo Masahiro
Published: March 2009

Shear-type fatigue crack behavior in a bearing steel, SAE52100, was investigated in a
biaxial fatigue testing machine using cylindrical specimens. Either of the following two types of
artificial defect with the total length of 400 ~ 440 %m and the depth of 200 ~ 300 %m was
introduced into the specimen surfaces: (a) a semi-elliptical pre-crack emanating from 2 adjacent
holes by a tension-compression loading, (b) 3 adjacent holes oriented in the axial direction which
had slits made by the focused ion beam technique at the both ends. Fully reversed torsion with a
shear stress amplitude at specimen surface, τa = ~ 600 MPa, was applied to the specimens under the
static axial compressive stress σm = −1000 ~ −1200 MPa. In case of the defect (a), a shear-type
crack propagated from the pre-crack in direction perpendicular to the specimen axis. At the
specimen surface, the shear-type crack periodically branched from the crack tip and propagated
5~10 %m in Mode I directions. The shear-type crack growth was decelerated with an increase in the
crack length and finally stopped at N ≅ 7.5×106 cycles and 2a ≅ 600 %m. On the other hand, in case
of the defect (b), the shear-type crack propagated in axial direction, and the crack growth was
accelerated with an increase in the crack length. In addition, the threshold stress in case without the
compressive stress on crack-face was determined by a τa-decreasing test. The results revealed that
the shear-type crack growth was strongly influenced by the crack-face friction and the existence of
the Mode I blanched cracks.
Low-Temperature Sintering of Nanoscale Silver Paste for Large-Area Joints in Power Electronics Modules
Authors: Lei Thomas G. , Calata Jesus , Luo Shu Fang , Lu Guo Quan , Chen Xu
Published: March 2009

Today, reflow soldering is a commonly used technique to establish large-area joints in
power electronics modules. These joints are needed to attach large-area (>1 cm2) power
semiconductor chips to the substrate, e.g., a direct-bond copper substrate, and the multichip module
substrate to a copper base plate for heat spreading. Thermal performance, specifically thermal
conductivity and thermomechanical reliability, of these large-area joints are critical to the electrical
performance and lifetime of the power modules. Soft solder alloys, including the lead-tin eutectic
and lead-free alternatives, have low thermal conductivities and are highly susceptible to fatigue
failure. As demands mount for higher power density, higher junction temperature, and longer
lifetime out of the power modules, reliance on solder-based joining is becoming a barrier for further
advancement in power electronics systems. Recently, we successfully demonstrated lowtemperature
sintering of nanoscale silver paste as a lead-free solution for achieving highperformance,
high-reliability, and high-temperature interconnection of small devices (<0.09 cm2).
In this paper, we report the results of our study to extend the low-temperature sintering technique to
large-area joints. The study involved redesigning the organic and inorganic components of the
nanoscale silver paste, analyzing the burnout kinetics of the various organic species sandwiched
between large-area plates, and developing desirable temperature-time profile to improve sintering
and bonding strength of the joints.
On Using Discrete Particle Approaches for Simulating the Perforation Process of Concrete Slab by Hard Projectile
Authors: Jiao Yu Yong , Zhang Xiu Li , Wang Shui Lin , Wu Huo Zhen
Published: March 2009

This study is to present a numerical investigation on fragmentation and perforation of
concrete slab by hard projectile using discrete particle approaches. Discrete Element Method (DEM)
and Discontinuous Deformation Analysis (DDA), the two representative discrete particle approaches,
are employed to simulate a normal perforation of concrete slab by a hard ogival-nose shaped
projectile, and the phenomena of spalling, plugging and scabbing are reproduced.
Fatigue Properties of Surface-Micromachined Al-3%Ti Thin Films
Authors: Park Jun Hyub , Myung Man Sik , Kim Yun Jae
Published: March 2009

This paper describes new structure of specimen easy to manipulate, align and grip a
thin-film and test machine for a fatigue test. High cycle fatigue test has been performed on tensile type
specimen of Al-3%Ti alloy using the newly developed fatigue test machine. The material used in this
study was Al-3%Ti thin film, which was used in RF MEMS switch. The structure of the suggested
specimen has two holes and several bridges. The holes at centre of grip end are able to make
alignment and gripping easy. The bridges are to remove the side support strip easily and extract
specimen from wafer without sawing. The test machine was developed using the voice coil of
speaker. The new tensile loading system has a load cell with maximum capacity of 0.5N and a
non-contact position measuring system based on the principle of capacitance micrometry with 0.1nm
resolution for displacement measurement. Fatigue tests was performed on 7 specimens. The thickness
and width of the thin film of specimen are 1.0μm and 150μm, respectively. The fatigue strength
coefficient and the fatigue strength exponent of Al-3%Ti alloy micro-sized specimen are determined
to be 164MPa and -0.01322, respectively
Application of Innovative GFRP Pipe Soil Nail System in Hong Kong
Authors: Cheng Y.M. , Wei Wen Bing
Published: March 2009

The current method of soil nail construction in Hong Kong is both labour intensive as well
as expensive and a search for new soil nail material is required. In the present pilot test, light weight
high strength and high corrosion resistance GFRP pipe with Tube a’ Manchette grouting technique is
used as soil nail instead of the conventional steel reinforcement. It is found that this material can be
handled easily on site with difficult access. From extensive laboratory as well as field tests, it is
demonstrated that this new soil nail technique has various advantages for use in Hong Kong and many
developed cities. The field test results on this innovative soil nail will be discussed in this paper.
Effect of Rotation to a Half-Sapce in Magneto-Thermoelasticity with Thermal Relaxations
Authors: Pan Ying , Zhang Zi Hou , Liu Li Hou
Published: March 2009

Based on Green and Lindsay’s generalized thermoelasticity theory with two relaxation
times, a two-dimensional coupled problem in electromagneto-thermoelasticity for a rotating
half-space solid whose surface is subjected to a heat is studied in this paper. The normal mode
analysis is used to obtain the analytical expressions for the considered variables. It can be found
electromagneto-thermoelastic coupled effect in the medium, and it also can be found that rotation
acts to significantly decrease the magnitude of the real part of displacement and stress and
insignificantly affect the magnitude of temperature and induced magnetic field.
Crack Formation of Ceramic Thin Film on Polymer Substrate
Authors: Omiya Masaki , Kishimoto Kikuo
Published: March 2009

The aim of this paper is to investigate the effect of ultra-violet (UV) ray irradiation on the
crack formation of brittle ceramic coating on polymer substrate. It is well known that ultra-violet ray
irradiation degrades the mechanical properties of polymer and polymer-based coating films. We
carried out the tensile tests of PET/ITO film specimen after UV irradiation under the microscope and
observed the crack formation on ITO surface. Also, we carried out nano-indentation tests of PET
substrate after removing ITO layer to characterize the change of the mechanical properties near the
interface between PET and ITO. The results show that the number of cracks vertical to loading
direction and the rate of vertical crack formation decreased after UV irradiation. Hardness and
Young’s modulus of PET substrate increase due to the oxidation of PET after UV irradiation. To
explain the relationship between the crack formation and mechanical property change, the energy
release rates of the thin film channeling cracks are considered.
Study on Structure of the New Polymer-Poly (Propylene-Co-γ-Butyrolactone Carbonate) with Molecular Model
Authors: Lu Ling Bin , Huang Ke Long , Wen Feng
Published: March 2009

Based on COMPASS forcefield, the relationship between microstructure and
macroscopic properties of poly (propylene-co-γ-butyrolactone carbonate) (PPCG) was firstly
investigated with ‘Materials Studio’ simulation soft successfully. The results of simulation showed
that the molecular chain of PPCG was flexible. Degradable carbonic and carboxylic ester groups
were distributed outside the PPCG cell. Furthermore the structure of micro-phase separation was
observed in PPCG cell. The structure of micro-phase separation of PPCG can be applied to the
self-assembly of drug molecule.
Intensity of Singular Stress at the End of a Fiber under Pull-Out Force
Authors: Noda Naoaki , Takase Yasushi , Shirao Ryohji , Li Jun , Sugimoto Jun Suke
Published: March 2009

In this study, singular stress fields at the ends of fibers are discussed by the use of models of
rectangular and cylindrical inclusions in a semi-infinite body under pull-out force．The body force
method is used to formulate those problems as a system of singular integral equations where the
unknown functions are densities of the body forces distributed in a semi-infinite body having the same
elastic constants as those of the matrix and inclusions.Then generalized stress intensity factors at the
corner of rectangular and cylindrical inclusions are systematically calculated with varying the elastic
ratio, length, and spacing of the location from edge to inner of the body. The effects of elastic modulus
ratio and aspect ratio of inclusion upon the stress intensity factors are discussed.
“Glass Cullet” Generation Technique by Underwater Shockwave for Recycling System of Glass Bottles
Authors: Kawabe Shinjiro , Sakamoto Hidetoshi , Satoh Kazuo , Himeno Masahiro , Itoh Shigeru
Published: March 2009

The high-speed fracture mechanics of glass bottles by using underwater
shockwaves technique and its application for recycling system of glass bottles were discussed.
The proposed small fragments, also called “Cullet”, generation technique can decrease the
recycling cost by carrying out of crashing and cleaning process simultaneously. In this study,
the effects of the explosive conditions and multi-specimen’s arrangements on the “Cullet”
sizes were investigated and basic data for commercialization of this method were obtained.
An FEM simulation and framing photograph were used to observe underwater shock wave
and fracture propagation.
Microstructure and Ferroelectric Domains of SrBi2Ta1.6Nb0.4O9
Authors: Ke Hua , Kou Xiao Jing , Lu Zhe , Li He Jun , Wang Wen , Jia De Chang , Zhou Yu
Published: March 2009

The microstructure and ferroelectric domains of SrBi2Ta1.6Nb0.4O9 ceramics were
investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM)
equipped with energy dispersive spectroscopy (EDS). The X-ray diffraction patterns show that the
lattice constants a and b decrease, and c increases by doping with Nb into SBT sample. Accordingly,
it has large strain and lattice distortion in the lattice This suggests that the Nb atoms partially occupy
the location of the Ta atoms in the lattice. From TEM observations, the grains show (008) preferred
orientations in the sample, which agrees well with the XRD results. The 90° domain walls are
identified by the 90° rotation relationship of the electron diffraction pattern about the [001] zone axis.
The 180° domain walls and anti-phase boundaries (APBs) in Nb-doped SBT ceramics are also
observed, which are irregularly shaped and highly curved. The traditional α-fringes can be found in
the Nb-doped SBT ceramics, which are the evidence of large strains in the lattice.
Distributions of α' Martensitic Phase Transformed on Fracture Surfaces of SUS 304 Stainless Steel Having Through- and Part-Through-Thickness Fatigue Cracks
Authors: Iwasaki Yoshifumi , Nakasone Yuji
Published: March 2009

The present paper investigates distributions of α’ martensitic phase on fracture surfaces of
plate specimens of SUS 304 stainless steel having through- and part-through-thickness fatigue cracks.
The volume fraction Vα’ of the α’ phase transformed on the fracture surfaces including the two types
of cracks was measured after specimens had been fractured due to fatigue at room temperature in air.
The measurements were made with ferrite scope. The contour maps of Vα’ revealed crack shapes
imprinted on the fracture surfaces of the specimens; i.e., nearly rectangular shapes on the fracture
surfaces of through-thickness-cracked specimens, whereas semi-elliptical shapes on the fracture
surfaces of part-through-thickness-cracked specimens. The values of Vα’ measured on crack surfaces
can be correlated with the maximum stress intensity factor values Kmax calculated at the points of Vα’
measurements. The resultant Vα’ vs. Kmax plots fall within narrow bands whose upper and lower
bounds are expressed by exponential curves. These results imply that quantitative post-fracture
analysis can be made by measuring Vα’ values on the fracture surfaces of structural components with
ferrite scope.
Effect of Solution Treatment Temperature on Properties of an Al11Si3Cu0.35Mg Cast Alloy
Authors: Wang Gui Qing , Zhao Zhong Kui , Liu Yan
Published: March 2009

The present work was performed on Al11Si3Cu0.35Mg samples cast in a permanent
mold preheated to 200 °C. The tensile properties for varies solution treated samples aged at 200 °C
for 6 h were examined in order to study the influence of solution temperature on the alloy properties.
The dissolution of copper-containing phases and the incipient melting were analyzed for cast
samples solution treated in the temperature range 500~520 °C for 8 h followed by quenching in
water. The influence of the incipient melting on mechanical properties has been discussed.
Generalized Drucker-Prager Strength Criteria
Authors: Zhou Feng Xi , Li Shi Rong
Published: March 2009

Based on the experimental and theoretic studies of the frictional materials in literatures, a
generalized non-linear strength theory is presented. The generalized strength theory has the same
mathematical form as classical Drucker-Prager strength (D-P) criteria. It describes strength
characteristics of various materials using a unified formula, and it includes or approximates
numerously present strength criterions. The shape of generalized Drucker-Prager (GDP) criteria is
convexly smooth curve between the classical D-P criteria (upper bound) and the external contour line
of Mohr-Coulomb (M-C) criteria (lower bound) on the deviator-plane, and a straight line on the
meridian-plane. Through variation of parameters in the criteria, a series of criterions ranging between
these two bounds may be introduced by the unified strength criteria, and the different strength
properties of various materials were denoted.
Micorstructure and Properties of 2Cr16Ni2MoN Stainless Steel
Authors: Zhong Ping , Li Song Mei , Shu Bin
Published: March 2009

The effect of heat treatment on the microstructure and mechanical properties of aged
hardening 2Cr16Ni2MoN stainless steel was examined. The steel contained undissolved
(CrFeMo)23C6 carbides in a martensite at lower solution treated temperature. Solution treating at
1100°C resulted in coarsening of the packet and block structure of the lath martensite. The optimum
solution treated temperature is 1040°C.Aging at 500°C resulted in peak strength due to the
precipitation of extremely fine coherent (CrFeMo)2C carbides. The optimum combination of
tensile strength and impact toughness was attained at the aging temperature of 560°C,was
attributed to both the formation of fine M2C in the lath and a mixture of lath martensite with
high density dislocations.
Compressive Deformation Behavior of the Ferritic Oxide Dispersion Strengthened Alloys at Elevated Temperatures
Authors: Qu Shou Jiang , Han Jie Cai , Meng Song He
Published: March 2009

The compressive properties characterized as a function of the true stress-strain response
of the ferritic oxide dispersion strengthened (ODS) alloys, fabricated by mechanical alloying, were
examined at strain rates ranging from 0.01 to 0.5s-1. Based on the differential scanning calorimeter
(DSC) analysis, the solidus temperature of the ferritic ODS alloys is 1446oC. Therefore, the
compressive temperatures were chosen to be from 1050oC to 1300oC. Transmission electron
microscopy (TEM) observation is indicative of the homogeneous distribution of the nano-yttria
particles with the granularity of 100~200nm, which may exert a strong pinning effect on subgrains.
The results indicate that flow stress of the ferritic ODS alloys enhances with decreasing
compressive temperature and increasing strain rate. Investigation of the strain rate sensitivity
exponent and apparent activation energy of the ferritic ODS alloys has been carried out in detail.
Strengthening of Cu-Ti2SnC Composites due to Microstructural Changes in the Material
Authors: Wu Jin Yi , Chai Ke
Published: March 2009

Ti2SnC dispersion-strengthened (DS) copper matrix composites were prepared by
hot-pressing method. The changes of mechanical properties of the composites as a function of
microstructure were studied. The results demonstrated that the grain size of Cu decreased
pronouncedly by incorporating of Ti2SnC, and the strengthening effect was significant. The addition
of 5 vol.% Ti2SnC particles to Cu resulted in a near five-fold increase in the yield strength and the
tensile strength also increased by 188 MPa. The magnitude of the increase was a function of the
change of the microstructure.
Morphology Evolutions of the Short Fatigue Crack Propagation of 1Cr18Ni9Ti Weld Metal
Authors: Zhao Yong Xiang , Yang Bing , Zhang Wei Hua
Published: March 2009

Surface and depth morphology evodslutions of short crack propagation of 1Cr18Ni9Ti
weld metal are investigated. In accordance with the previous effective short fatigue crack (ESFC)
criterion, attention is paid on the formation zone of the dominant ESFC (DESFC), which resulted
finally in the specimen failure, in micro-structural short crack (MSC) regime and then, the tip zone(s)
ahead of the DESFC in physical short crack (PSC) regime. Results show that in MSC regime the
surface ESFCs were imitated from the distributed randomly delta ferrite bounds separated from
austenite matrix. The initiated ESFCs on surface propagated perpendicularly to loading axle. But in
depth direction, the initiated ESFCs grew first similarly to the surface behaviour but lately, tended to
be perpendicularly to the formation direction of the material columnar grain structure. When sizes of
some longer ESFCs reached around the material maximum barrier size, coalescence occurred to form
a true DESFC. In PSC regime the surface DESFC grew almost perpendicularly to loading axle. But in
depth direction, it grew first perpendicularly to the formation direction of the columnar grain structure
and then, tended to having 45 degree angle to the loading axle. Obviously, the evolutions were
strongly affected by interactions between the load and the microstructures, especially, the columnar
grain structure.
Finite Element Study of Factor Effects on Residual Stresses and Thermal Deformation of Brazed Plate-Fin Structure
Authors: Chen Hu , Gong Jian Ming , Tu Shan Tung , Geng Lu Yang
Published: March 2009

The brazed plate-fin structure is the key component of a compact plate-fin heat exchanger
(PFHE). The thermal deformation and residual stresses induced by vacuum brazing may bring
negative effects on the quality and the life of the plate-fin structure. Thus it is important to optimize
the brazing parameters in order to minimize such effects. This paper presents a three-dimensional
finite element analysis for determining the thermal deformation and residual stresses of a three layers
of stainless steel plate-fin structure fabricated by nickel-based brazing. The feature of thermal
deformation and residual stresses distribution are discussed. The effects of three major factors
including brazing temperature, clamping pressure and filler metal on the thermal deformation and
residual stresses are investigated respectively.
Crack Growth in Stainless Steel 304 under Creep-Fatigue Loading
Authors: Baik Y.M. , Kim K.S.
Published: March 2009

Crack growth in compact specimens of type 304 stainless steel is studied at 538oC. Loading
conditions include pure fatigue loading, static loading and fatigue loading with hold time. Crack
growth rates are correlated with the stress intensity factor. A finite element analysis is performed to
understand the crack tip field under creep-fatigue loading. It is found that fatigue loading interrupts
stress relaxation around the crack tip and cause stress reinstatement, thereby accelerating crack
growth compared with pure static loading. An effort is made to model crack growth rates under
combined influence of creep and fatigue loading. The correlation with the stress intensity factor is
found better when da/dt is used instead of da/dN. Both the linear summation rule and the dominant
damage rule overestimate crack growth rates under creep-fatigue loading. A model is proposed to
better correlate crack growth rates under creep-fatigue loading:
1
c f
da da da
dt dt dt
Ψ −Ψ    
=    
   
, where Ψ is an
exponent determined from damage under pure fatigue loading and pure creep loading. This model
correlates crack growth rates for relatively small loads and low stress intensity factors. However,
correlation becomes poor as the crack growth rate becomes large under a high level of load.
Characteristics of High Temperature Tensile Properties and Residual Stresses in Welded Joints of the SM570-TMCP Steel
Authors: Lee Chin Hyung , Park H.C. , Jang Gab Chul , Lee J.H. , Chang Kyong Ho
Published: March 2009

TMCP steels produced by thermo-mechanical control process are now spot lighted due to
the excellent combinations of strength, toughness and weldability. Recently, in Korea, high strength
SM570-TMCP steel whose tensile strength is 600MPa has been developed and applied to steel
structures due to its excellent nature. But, for the application of the TMCP steel to steel structures, it is
necessary to elucidate not only the material characteristics but the mechanical characteristics of
welded joints. In this study, high temperature tensile properties of the SM570-TMCP steel were
investigated through the elevated temperature tensile test and the characteristics of residual stresses in
welded joints of the TMCP steel were studied through the three-dimensional (3-D) thermal
elastic-plastic finite element (FE) analysis on the basis of mechanical properties at high temperatures
obtained from the experiment. The results are then compared with the conventional quenched and
tempered high strength SM570 steel.
Segregation of Alloying Elements of Directionally Solidified Nickel Based Superalloy CM247LC during Creep Degradation Process
Authors: Niki Takahiro , Ogawa Kazuhiro , Shoji Tetsuo
Published: March 2009

The mechanism of the degradation process of nickel based superalloy CM247LC under
creep loading was analyzed by considering the microscopic chemical composition of the material
such as phase boundary of γ and γ’ phases.
In this study, a Directionally Solidified (DS) nickel-based superalloys CM247LC was used as test
specimens. The creep test was performed at 900oC under an uni-axial stress of 216 MPa. Each
specimen was creep ruptured and interrupted at different hours and then analyzed.
The change of chemical composition around the interface analyzed precisely by used Auger
Electron Spectroscopy (AES). It was found that the local enrichment or lack of cobalt and
chromium was found at the interface. This tendency was not found in the stress free area. Since
chromium is the well-known element that dominates the degradation of this material, such an
enrichment or lack of cobalt and chromium may play an important role for forming a crack
propagation path near the interface. This local segregation should be analyzed further to make clear
degradation mechanism of this material.
Fatigue Crack Growth Rate in Low ΔK Range According to the Microstructure and Temperature in P122 Alloy Weldment
Authors: Bae Si Yon , Kim Bum Joon , Lim Byeong Soo
Published: March 2009

There exists strong environmental and economic pressure to increase the thermal efficiency
of fossil fuel power stations and this has led to a steady increase in operating temperature and pressure
resulting in the world wide construction plans for ultra super-critical power plants. Consequently, in
order to improve the thermal efficiency of power plant, there has been a strong drive to develop more
advanced heat resistant steels with excellent creep, high temperature fatigue and thermal fatigue
resistant properties as well as superior oxidation and corrosion resistant properties. In this study, the
test material was P122 alloy which was developed for ultra super-critical power plant. To measure the
fatigue crack growth rate in low #K range, fatigue tests were performed on the P122 alloy welds by
#K decreasing method at three different microstructure (Base metal, HAZ, Weld metal) regions.
Microstructure observation and micro-hardness tests performed for all three regions to find the
relationship among the crack growth rate, microstructure and hardness. Fatigue tests were performed
with compact tension specimens at 600°C, 650°C and 700°C at the loading frequency of 20Hz.
Uniaxial Cyclic Deformation Behaviors of 42CrMo Steel with Different Heat-Treatments
Authors: Kang Guo Zheng , Li Zhao , Liu Yu Jie
Published: March 2009

The cyclic deformation behaviors of 42CrMo steel with different heat treatments were
observed by uniaxial cyclic straining and stressing tests at room temperature. The cyclic softening/
hardening features of the tempered or annealed 42CrMo steel and their effects on the uniaxial
ratcheting produced in asymmetrical cyclic stressing were discussed. It is concluded that the
tempered 42CrMo steel shows significantly cyclic softening feature, but the annealed one is cyclic
stabilizing. Different ratcheting behaviors are also observed. For the tempered 42CrMo steel, a
special tertiary ratcheting behavior is observed and the previous cyclic straining greatly accelerates
the evolution of ratcheting strain in subsequent cyclic stressing. In contrast, the annealed sample
presents a stabilized ratcheting with nearly constant ratcheting strain rate after certain cycles, and
the previous cyclic straining slightly influences the ratcheting in subsequent cyclic stressing.
Characteristics of Strength and Deformation of Inner/Outer Local Wall Thinned Straight Pipes
Authors: Ahn Seok Hwan , Seok Kum Cheol , Nam Ki Woo
Published: March 2009

The experimental and the analysis for effects of circumferentially local wall thinning on
the fracture behavior of pipes were carried out. Local wall thinning for experimental was machined
on the outside of pipes in order to simulate the metal loss due to erosion/corrosion. In addition, the
pipes with local wall thinning on the inside were carried out FE analysis, and it made a comparative
study with that of outside. Failure mode could be classified into ovalization, local buckling and
crack initiation depending on the thinned length and thinned ratio. Three-dimensional elasto-plastic
analyses were able to accurately simulate fracture behaviors of inner/outer local wall thinning.
Therefore the fracture behavior of the inner local wall thinning can be estimated with the outer local
wall thinning.
Microstructure and Tensile Properties of a Mg-Zn-Y-Zr Alloy Containing Quasicrystal Phase Processed by Equal Channel Angular Pressing
Authors: Xu Shi Wei , Zheng Ming Yi , Qiao Xiao Guang , Gan Wei Min , Wu Kun , Kamado Shigeharu , Kojima Yo
Published: March 2009

Equal channel angular pressing (ECAP) was performed on extruded Mg-Zn-Y-Zr
(Mg-5.0wt%Zn-0.9wt%Y-0.2wt%Zr) alloy at 300 oC. After 8 ECAP passes, average grain size of
the alloy was reduced to about 1.4 μm, and the quasicrystalline phases were broken and dispersed in
the matrix. In addition, nano- quasicrystallines were precipitated from the matrix during ECAP
processing. After ECAP, the elongation to failure of the extruded material was significantly
improved. Only after 2 ECAP passes, the elongation to failure was 29%, and after 8 ECAP passes, it
reached 35%, which was three times larger than that of the as-extruded alloy. However, both yield
strength and ultimate tensile strength were decreased with the increasing ECAP passes, which was
considered to be resulted from the {0002} basal plane texture modification during ECAP.
Dynamic Restoration Process of 7050 Aluminum Alloy during Superplastic Deformation
Authors: Hu H.E. , Zhen Liang , Zhang Xin Mei , Zhang Bao You , Chen J.Z. , Li G.A.
Published: March 2009

The superplastic deformation and microstructure evolution of solid solution treated 7050
aluminum alloy has been investigated. Tensile were conducted at 420 and 460 °C with the strain rate
of 1.0×10-4 ~ 1.0×10-1 s-1, and the deformed samples were characterized using optical microscopy,
scanning electron microscopy and electron backscatter diffraction. The results show that the solid
solution treated 7050 aluminum alloy gained the maximum elongation of 273% at 460 °C with the
strain rate of 1.0×10-2. At the deformation condition, a large part of plastic deformation was
completed at an invariable stress. The microstructure transformed from coarse grains to a bimodal
microstructure and then to a nearly uniform fine microstructure and the dynamic restoration process is
from dynamic recrystallization plus dynamic recovery to dynamic recrystallization with the
increasing deform strain during superplastic deformation.
Reconstruction of the Material Probabilistic S-N Relations with Given Confidence
Authors: Yang Bing , Zhao Yong Xiang , Zhang Wei Hua
Published: March 2009

Because of the huge cost involved in data acquisition, probabilistic S-N relations should be
given on a wide applicable sense to perform the reliability analysis at arbitrary survival
probability-confidence (P-C) level. However, some existent fatigue databases give the material
probabilistic S-N relations only with several fixed P-C levels. To realize the reliability analysis on a
sense of arbitrary P-C level, a Monte Carlo simulation method is presented for reconstruction of the
relations. Test data are re-gotten by a method under the new simulation policy that matching
production practice according to original statistical parameters. Details are given with respect to the
possible cases of known conditions. The relations are finally determined by maximum likelihood
estimation on a general model to realize the analysis at arbitrary P-C level. Reconstruction of the
relations for 60Si2Mn spring steel has indicated the availability and feasibility of present method.