bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Simulation of Fracture Process Zone in Concrete Tension Specimen
Authors: Huang Ming Li , Xu Tao , Wang Fei , Zhu Wan Cheng
Published: March 2009

In this paper, some numerical tests on the fracture process zone (FPZ) in concrete tension
specimen were carried out with Material Failure Process Analysis code (MFPA2D) to investigate the
behavior of the FPZ and the effect of the meso-scale heterogeneity of concrete on fracture process.
The numerical results provide a clear indicator of the FPZ of concrete. The numerical results show
that the FPZ accompanied by AE events gradually develops ahead of the notch tip with the increase of
the loading in the concrete tension specimen. Moreover, many of the AE events bring about very
small energy at the beginning of loading stage. Zones of higher energy events demonstrate a
localization zone around the notch tip. The zones of AE events progresses forward gradually, and
much densely distributed AE events can be observed in the FPZ. Moreover, the numerical simulations
about AE events agreed well with those of the microcracks obtained by laboratory findings.
On the Relations between the Threshold Values of the Fatigue Crack Growth and the Cyclic Deformation Behavior of Materials
Authors: Sun Yi , Zhang Rui , Qu Jian Min
Published: March 2009

In the present paper, the relation between fatigue crack growth threshold and material’s
cyclic saturation behavior is investigated. The dislocation-free zone (DFZ) model is used to
determine the dislocation distribution ahead of the crack tip. A cohesive zone model is developed to
determine the stress field of the DFZ under cyclic loading. The effect of cyclic loading makes the
plastic zone hardening (or softening), which raises the stress level in DFZ, and may lead to fracture.
It is found that the near threshold characteristics are mostly determined by the cyclic deformation
behavior of the material, and might be theoretically determinable from the standard cyclic loading
test.
Investigating Morphology Evolution of Damage by a Cellular Automaton Modelling
Authors: Zhang Jing , Song Nai Hui , Li Xiao Peng , Ren Zhao Hui , Wen Bang Chun
Published: March 2009

A two-dimensional cellular automaton (CA) model is developed to simulate damage and
fracture morphology evolution on the mesoscale in materials. The plastic convection of damage is
mapped onto the CA lattice, and initiation, propagation and coalescence of damage are simulated
with a local rule-based scheme of a probability cellular automaton. The model includes known
physical distinctions of fracture behavior between microcracks and microvoids, and they are
characterized by modifying the probability rule of the cellular automaton. The simulations provide
visual insight to understand how those physical processes dynamically progress and they affect the
damage evolution in materials. The modeling can be used to link micromechanical models to
continuum damage models.
Finite Element Analysis of Blower Impeller Using Cyclic Symmetry
Authors: Kim Chang Boo , Ahn Young Chul , Kim Bo Yeon , Cho Chong Du , Beom Hyeon Gyu
Published: March 2009

In this paper, we present an efficient method for conducting a finite element analysis of a
structure with cyclic symmetry and apply the method to analyze the natural vibration and linear and
non-linear static characteristics of a blower impeller. A blower impeller is composed of
circumferentially repeated substructures. The whole structure is partitioned into substructures, and the
finite element analysis can thus be performed with one representative substructure by using the
transformed equations for each number of nodal diameters, which are derived from a discrete Fourier
transform. We calculated the natural vibration and linear and non-linear static characteristics of a
blower impeller without a stiffening ring, and with small as well as large stiffening rings, respectively.
The accuracy and efficiency of the presented method are verified by comparison of the results
obtained from the analysis using a substructure to those obtained using the whole structure.
Numerical Simulation of Thermal Stress Field of Arc-Shaped Thermal-Protection Component
Authors: Lu De Sheng , Zhou Yu , Wang Bei , Wang Yu Jin , Ouyang Jia Hu , Ke Hua
Published: March 2009

For the purpose of studying material cluster design and shape design of a certain
arc-shaped thermal-protection component rationally, the ablation behavior and thermal stress
distribution are studied by using the method of finite element numerical simulation. The study
includes ablation tests, numerical simulation of temperature field, calculation of ablation thickness
and numerical simulation of unsteady thermal stress field of the component. The simulation results
are consistent with the results of ablation tests, which shows that the shape design of the arc-shaped
thermal-protection component is rational and the dangerous periods of the component ablation are
the time of initial heating and initial ablation boundary retreat.
A Simple Plastic-Damage Model for the Cement-Soil Admixture
Authors: Yu X.J. , Fang Zhen , Wang Shan Yong , Yan Yun , Yin Jian Hua
Published: March 2009

An Elastic Plastic-Damage (EPD) model is developed to model the softening behaviour of
the cement-soil admixture based on continuous damage mechanics. The softening behaviour is
considered to be characteristic outcome of the material degradation due to damage in material.
Material degradation is modelled by reducing progressively the stiffness and yield stress of the
material when the damage variable has attained a critical index. The basic equations of the model are
derived and presented. A Fortran program for this model has been developed and implemented into a
finite element code ABAQUS. In order to evaluate the applicability of this model, several unconfined
compression tests are simulated using ABAQUS with this model. The computed results are compared
with measured data and good agreement is achieved.
Relationship between Fracture Mechanism and Microstructure in PLA/PCL Polymer Blends
Authors: Takayama Tetsuo , Todo Mitsugu , Arakawa Kazuo
Published: March 2009

PLA/PCL and PLA/PCL/LTI blends were developed to improve the fracture properties of
biodegradable PLA. LTI was blended to improve the miscibility of PLA and PCL. It was shown that
the fracture toughness values were dramatically increased due to LTI addition. SEM results also
exhibited that PCL spherulites decreases due to LTI addition and therefore, void formation is
reduced and local stress concentration is suppressed, resulting in the improvement of the toughness
values. The improved miscibility is also closely related to the enhancement of ductile deformation;
as a result, the fracture toughness is increased.
Estimation of the Elastic-Plastic Fracture Behavior of Fiber Reinforced MMC According to the Change of Interfacial Characteristics
Authors: Kang Ji Woong , Kwon Oh Heon
Published: March 2009

Fiber reinforced metal matrix composites (MMCs) are recently used in automobile, ship,
aerospace and manufacturing industry because they have high stiffness and strength. The effective
utilization of the strength and stiffness of the fiber reinforced MMCs depends on efficient load
transfers from the matrix to fibers through the interfacial region. However, during the fabrication
and afterward utilization of composites, so many numbers of micro crack may extend, especially at
the interface, even before any load has been applied. Thus, in this study, the interfacial stress state
and behavior of the interfacial perpendicular crack for transversely loaded unidirectional fiber
reinforced MMCs investigated by using the elastic-plastic finite element analysis.
Effect of Microstructure on Small Fatigue Crack Initiation and Propagation Behavior of Ti-6Al-4V Alloy
Authors: Komano K. , Ishihara Sotomi , McEvily A.J. , Shibata H.
Published: March 2009

Fatigue tests were performed in laboratory air using extruded Ti-6Al-4V to determine the
effect of microstructure on S-N curve, and the crack initiation and crack propagation behavior of the
alloy. A modified linear elastic fracture mechanics approach was used in the analysis of the short
crack propagation behavior to predict the S-N curve and the crack propagation curve. The
predictions agreed well with the experimental results.
Viscoelastic Deformation of PC/ABS Alloy
Authors: Yin Z.N. , Fan L.F. , Wang Tie Jun
Published: March 2009

Dynamic Mechanical Analysis (DMA) and static relaxation tests are carried out to study
the viscoelastic deformation of PC/ABS alloy with blending ratio of PC to ABS being 50/50. A
modified approach is developed to calculate the relaxation modulus of PC/ABS alloy from the DMA
experimental results of storage and loss moduli. Comparison of the results obtained from DMA and
static relaxation tests is presented and good agreement is found.
Damage Monitoring of Thick CFRP Beam Using Electrical Impedance Changes
Authors: Todoroki Akira , Ueda Masahito , Shimamura Yoshinobu
Published: March 2009

Electrical resistance change method has been applied to monitor a delamination crack of
a thin CFRP laminate. For a thick CFRP laminate, multiple delamination cracks are made with
many matrix cracks, and the electric current in the thick CFRP laminate may not flow in the
thickness direction due to the strong orthotropic electrical conductivity. The present study employs
an electric impedance change method for the identification of damage location and dimension of the
damaged area; applicability of the method is investigated experimentally using thick beam-type
specimens fabricated from cross-ply laminates of 36 plies. After making the damage, electrical
impedance was decreased. A residual stress relief model was proposed to explain the decrease.
From the measured electrical impedance changes, the relationships between the electrical
impedance changes and damages are obtained by means of response surfaces. The response surfaces
estimated the damage location and dimension of the damaged area exactly even for the thick CFRP
laminates. The electrical impedance change method can be used as an appropriate sensor for
measurement of residual stress relief due to damages of thick CFRP laminates.
Laser Processed Intermetallic Matrix Composite Coatings on Ni-Based Superalloy Substrate
Authors: Fan Ding , Sun Yao Ning , Zhang Jian Bin , Sun Ming
Published: March 2009

Carbides reinforced intermetallic matrix composite coatings for elevated temperature
environmental resistance were prepared on Ni-based suaperalloy substrate using CO2 laser cladding
process. The phases of clad layer were investigated by scanning electron microscopy (SEM), X-ray
diffractometer (XRD) and energy-dispersive spectrometer (EDS). The laser cladding of the
Ni78Si13Ti9/WC powder shows that the products mainly consist of TiC, WC and Ni3(Si,Ti) phases.
A chemical reaction between WC particle and Ti powder occurs during the laser process, therefore
TiC is formed. The microhardness of the samples increases with the increase of the content of WC.
Effect of Contact Pressure and Cyclic Stress Amplitude on Fretting Fatigue of 45-Carbon Steel
Authors: Sun Wei Ming , Chen Shui Sheng , Tu Li Qun
Published: March 2009

The effect of contact pressure on fretting fatigue in quenched and tempered 45-carbon steel
is studied. With an increase in contact pressure, fretting fatigue life is decreased quickly at low contact
pressures; however it almost unchanged at high contact pressures. With an increase in cyclic stress
amplitude, fretting fatigue life decreased. In the test, concavity is formed at the fretted area
accompanying wear. The main crack is initiated at the outer edge corner of the concavity at high
contact pressures, and initiated at the middle portion of the fretted area at low contact pressures.
Some Crystallographic Features of the Boron-Doped Diamond Single Crystals Synthesized by Fe-Ni-C-B System under HTHP
Authors: Su Qing Cai , Gong Jian Hong , Li He Sheng , Xu Bin , Li Mu Sen , Zhao Ji Qing , Chen Lu
Published: March 2009

Boron-doped diamond single crystals were synthesized with Fe-Ni-C-B System catalysts
which content of boron carbide (B4C) were different, and their crystallographic features were tested
with electron probe microanalysis (EPMA), X-rays diffraction (XRD), Raman spectrum and field
emission scanning electron microscopy (FESEM). The experimental results showed that doped
boron in the diamond could result in the changes of its crystallographic features. There were
different X-ray peak intensities in the different boron-doped diamond crystals, and the intensities
were changed with the content of B4C in the catalysts. With the increase of boron content in the
diamond, the boron atoms resulted in the change of growing rate in different crystalline face of the
diamond. The quality of diamond synthesized with catalyst which contained 0.2 w.t.% boron
carbide was worse than others.
Influences of Micropowder Gradation on Rheological Properties of Cement-Based Composite Pastes
Authors: Gong Jian Qing , Xiao Han Ning , Huang Zheng Yu , Li Jiu Su , Nie Jing , Mao Dan
Published: March 2009

The rheological parameters of cement pastes were investigated by varying the type and
content of micropowders and the ratio of water to binder. Compressible packing model was used to
calculate the packing density and to evaluate the influence of micropowders gradation on the
rheological properties of fresh cement pastes. Results indicate that the higher the packing density is,
the lower the yielding shear stress and plastic viscosity will be. When the ratio of water to binder is
less than 0.20, the cement paste with 15% UFA and 15% SF has highest packing density and lowest
yielding shear stress and plastic viscosity, which is beneficial to the workability of ultra-high
performance concrete.
Study on Solvent Debinding Process of Powder Injection Molded Ti(C, N)-Based Cermets
Authors: Yan Ming Shuang , Xiong Wei Hao , Fan Chou
Published: March 2009

The solvent debinding processes of wax-based binders in powder injection molded
Ti(C,N)-based cermets were studied. Effects of debinding temperature, debinding time, sample
thickness, solvent types and solvent concentration on binder removal were investigated. Also, the
dimension change of samples during the solvent debinding process was studied. It can be found that
upwards of 70% paraffin waxes were removed and open pore channels were formed basically when
the samples were immersed in heptane for 6 h at 50 °C.
Influence of Mischmetal on Performance of Copper Based Electric Contact Materials
Authors: Guo Zhong Quan , Geng Hao Ran , Wang Bin , Hao Zhao Xi , Wang Zhi Ming
Published: March 2009

This paper suggested that the addition of a proper amount of mischmetal efficiently
improved the contact face and its mechanism of contact materials, enhancing their electrical
conductivity. At the same time, their inoxidizability and non-fusibility were also highly improved,
while the temperature elevation of the contactor during operation was dramatically reduced.
Flexural Strength of Superfine Grained Si2N2O-Si3N4 Composites
Authors: Luo Jun Ting , Zhang Qing , Zhang Kai Feng
Published: March 2009

The Si3N4- Si2N2O composites were fabricated with amorphous nano-sized silicon nitride
powders by the liquid phase sintering(LPS) method. The sintering temperatures ranged from 1500°C
to 1700°C. Microstructure and component of the composites were performed by scanning electron
microscopy (SEM) and X-ray diffraction (XRD). Results show that sintered body consists of Si2N2O
and β-Si3N4, with an average grain size about 1μm. The maximum value of flexural strength of the
material is 680MPa when sintered at 1700°C. Transcrystalline cracking is the main fracture
mechanism of the composites.
Effect of Electromechanical Loadings on Fracture Strength of Piezoelectric Ceramics
Authors: Nam Byeung Gun , Na H.S. , Liu R. , Watanabe Katsuhiko
Published: March 2009

The effect of electromechanical loadings including their sequence, which was motivated by
the property of crack energy density for piezoelectric material, was experimentally investigated.
Three-point bending fracture test was performed for two piezoelectric ceramics under different
electromechanical loading conditions. It was found that the fracture loads under closed circuit
condition are greater than those under open circuit condition. Effect of applied electric field on
fracture load in the test varied with materials. Applied electric field always enhanced crack extension
in C-21 ceramics regardless of their directions, while it produced very little effect on crack extension
under negative electric fields in C-2 ceramics. It was also found that electromechanical loading
sequence clearly affects fracture strength, although its effect varies also with materials.
Bi-Axial Flexure Strength, Weibull Modulus and Fracture Mode of Alumina Glass-Infiltrated Core/Veneer Ceramic Composites
Authors: Cui Jun , Chen Yi Fan , Chao Yong Lie , Chen Chun Xia , Ou Jun , Sui Lei , Zhang Wei Qun
Published: March 2009

The purpose of this study is to determine the bi-axial flexural strength, weibull modulus
and fracture mode of bilayered alumina glass-infiltrated core and the veneering porcelain. Forty
disk specimens were fabricated from alumina glass-infiltrated core (HSDC-A) and veneer
porcelain (Vintage AL). The specimens were equally divided into four groups as: MV, monolithic
specimens of veneer material; MC, monolithic specimens of core material; BV, bilayered
specimens with the veneer in tension; BC, bilayered specimens with core material in tension.
Mean flexure strength, standard deviation and associated Weibull modulus were determined using
bi-axial flexure (ball-on-ring) for each group. Both optical and scanning electron microscopy were
employed for identification of the fracture mode and origin. The surface loaded in tension
influenced the bi-axial flexural strength and reliability of the composites. The frequency of
specimen delamination, Hertzian cone formation and sub-critical radial cracking in the bilayered
discs are also dependent on the surface loaded in tension.
Microhardness and Machinability of Fluorphlogopite-Mullite Glass-Ceramics
Authors: Yu Li Ping , Xiao Han Ning , Cheng Yin
Published: March 2009

Effects of mullite on the structure, microhardness and machinability of fluorphlogopitemullite
glass-ceramics were investigated by X-ray diffractometry (XRD), differential scanning
calorimetry (DSC), scanning electron microscopy (SEM) and microhardness tester. Results show
that the microhardness and machinability are related closely to its microstructure. The microhardness
decreases remarkably with the increase of crystallization and the formation of interlocking
structure. The addition of mullite can decrease the size of mica crystals, which results in the spoil of
interlocking structure. The microhardness of the glass-ceramics is slightly increased and then
decreased with the addition of mullite. When the content of mullite is 15wt%, the glass-ceramics
shows good machinability after reheated at 1200°C for 2h.
Effect of Annealing Temperature on Microstructure and Properties of Surface Nanocrystalline Structure in Low Carbon Steel Specimen
Authors: Fan Xin Min , Ji Yan Jiao , Huang Jie Wen
Published: March 2009

Nanostructure surface layer was fabricated on a low carbon steel cylinder specimen by
means of circulation rolling plastic deformation (CRPD), and the effect of annealing temperature on
microstructure and properties of surface nanocrystalline structure was studied. The microstructure of
the surface layer on the samples was observed by transmission electron microscopy and the
microhardness variation along the depth was measured on the cross-sectional samples by using
microhardness instrument. After CRPD treatment for 250min, the average grain size was about 10nm
in the top surface layer and increased with an increment of the distance from the top surface. The
surface nanocrystallization samples were annealed at 200°C, 300, 400°C and 500°C for 30min
respectively. The nanocrystallization grain of surface layer did not grow for samples after annealed at
200°C and 300°C. After surface nanocrystallization by CRPD treatment the microhadness of top
surface obviously increase from 220HV0.1 to 520HV0.1.
Ageing Processes of Li-Containing Al-Zn-Mg-Cu Alloys
Authors: Zhao Zhong Kui , Zhou Tie Tao , Liu Pei Ying , Chen Chang Qi
Published: March 2009

1.1%Li was added to 7075 alloys to obtain the Li-containing Al-Zn-Mg-Cu alloys. The
microstructure and hardness of the alloys are investigated by transmission electron microscopy
(TEM) and Vickers hardness. The hardness of the single-aged alloys is low. When the alloys were
double-aged or multi-aged, the hardness is comparable to that of Al-Zn-Mg-Cu alloys at peak
ageing. Two peaks were present in the hardness curves of the multi-aged Li-containing
Al-Zn-Mg-Cu alloys. With the last-step temperature increases, two-peak phenomenon becomes
prominent. The density and size of precipitates are influenced remarkedly by the ageing processes.
Coarse grain boundary precipitates and PFZ (precipitate free zone)can be observed when the
Li-containing Al-Zn-Mg-Cu alloys were multi-aged, and the higher the last-step ageing temperature,
the wider the PFZ is.
Microstructure of Fe-Based ODS High-Temperature Alloy Sheet Prepared by EBPVD
Authors: Lin Xiu , Sun Yue , Song Guang Pin , He Xiao Dong
Published: March 2009

Large-sized Fe-based ODS (Oxide Dispersive Strengthen) high-temperature alloy sheets
were successfully synthesized by EBPVD (Electron Beam Physical Vapor Deposition) technique. The
sheets were about 120μm thick, and having a diameter of 1000mm, whose surface roughness was less
than 1μm (Ra<1μm). The microstructures were examined by SEM (Scanning Electron Microscope).
The grain size was 1-4μm. When the substrate temperature was 600°C, the sheet had sharp irregular
polyhedral grain, and when the substrate temperature was 700°C the sheet had quite regular grains.
The morphological orientation angle increased with the distance from the center of the sheet. During
the first period of deposition, the sheet was growing in a G-L-S mode, which corresponded with the
corn-like microstructure in the cross-section. While during the final period, the sheet changed into a
G-S growing mode, which corresponded to the smooth columnar microstructure.
Microstructure and Properties of Low Temperature Deposit CrxN Using Unbalanced Magnetron Sputtering
Authors: Bao Ming Dong , Xu Xue Bo , Sun Hai Lin , Teer Dennis , He Jia Wen
Published: March 2009

CrxN coatings are deposited on the substrates with low temperature using a Teer UDP
550 Close Field Unbalanced Magnetron Sputter Ion Plating system (CFUBMSIP). The effect of
applied power on Cr targets related to sample temperature is studied. When the applied power of Cr
targets is lower than 1.1KW, the depositing temperature could be controlled at about 180°C. Scratch
test shows no coating detachment at the end of scratch track up to 85N load. All results of
Rockwell-C indentation indicate that CrxN coating holds good bonding strength. Pin-on-disc tests
are performed to evaluate wear resistance of the coatings and no any wear loss can be detected after
6000s and 1800s of running. XRD profile demonstrates that the coating deposited in this study is
CrxN.
Microstructure and Optical Properties of Ag/TiO2 Multilayers
Authors: Wang Zhen Guo , Cai Xun
Published: March 2009

The microstructure of Ag/TiO2 and Ag/Ti/TiO2 multilayer system are investigated by
AFM and TEM, and their interfaces are analyzed by the means of spectroscopic ellipsometry (SE).
The results show that the multilayer has a sharp interface without interdiffusion and interface
reaction products. AFM surface roughness analysis indicates a 2-nm titanium transition layer can
improve surface quality of silver films, because it is enabled to change silver island dimension and
distribution and improve coverage of silver films on Ti/TiO2 substrate. This can be attributed to
titanium ׳s strong oxygen affinity and good wettability to titanium dioxide. The optical properties
test of TiO2/Ag/TiO2 multilayer demonstrates surface plasma resonance (SPR) absorption shifts
towards long wave region with the increasing of the total thickness of dielectrics.
Friction and Wear of Lubricated Sliding Surfaces of Coated Vane and Flange in Rotary Compressor with Carbon Dioxide as a Refrigerant
Authors: Jeon Hong Gyu , Lee Kyu Sun , Cho Sung Oug , Lee Young Ze
Published: March 2009

Due to the environmental concerns, especially the greenhouse effect and GWP (Global
Warming Potential), the carbon dioxide was investigated as an alternative natural refrigerant to
replace HFCs (HydroFluoroCarbons) in refrigerator or air conditioning systems. To develop new
compressor, especially rotary type, the friction and wear characteristics of sliding surfaces between
vane and flange in the rotary compressor were evaluated in this paper. Several hard coatings, such
as TiN, CrN and WC/C, were applied on vane surfaces in order to improve the tribological
characteristics, and their performances were evaluated experimentally. The vane-on-flange type
lubricated sliding tests were performed with a high pressure wear tester using HFC (R410A) and
carbon dioxide. From the tests, wear volumes of vane surfaces applied with various coatings were
compared each other.
Research on Surface Low Alloy HSS by Plasma Surface Metallographic W, MO, C Alloying
Authors: Gao Yuan , Xu Jin Yong , Xu Zhong
Published: March 2009

This research tries to improve the plasma surface W, Mo alloying process by adding inlet
methane aside from the original inert gas argon. The carbon and hydrogen particles are incorporated
into the ion sputtering, ionization, surface activation and diffusion processes. The W, Mo atoms
sputtered from the target diffuse into the surface of the substrate at the same time with the diffusion
of carbon atoms. So the synergism of the alloying process and the carburizing process is established
in this way. The hydrogen atoms participate the reduction and activation process on the surface of
the target and the substrate. The surface HSS combines with substrate via metallurgical bonding and
the carbides are all secondary carbides formed at lower temperature during solid state diffusion.
These carbides are very soluble to the austenite. This makes the alloy elements fully functional. The
carbides with granular shape and distributes homogeneously on the matrix are very fine. No coarse
ledeburite eutectic carbide exists. After the co-alloying process of W, Mo, C, direct quench or
quench at lower temperature can be applied.
Collaboration Tasks on Physical and Fundamental Properties of Plasma Sprayed Thermal Barrier Coatings in Japan Society of Materials Science
Authors: Ogawa Kazuhiro
Published: March 2009

The subcommittee on superalloys and coatings, The Society for Materials and Science,
Japan (JSMS) was established in 1997. As second stage of the committee, we investigated a
fundamental study on thermal plasma sprayed thermal barrier coatings (TBCs). Especially,
relationships between spray conditions and coating properties are discussed. It was used 4 spraying
conditions such as 1) standard condition, 2) larger particle used and lower velocity, 3) normal particle
used and lower velocity, and 4) standard condition and heating up the substrate to 473K. As a round
robin test, porosity ratio, residual stress, and bonding strength were evaluated by several techniques
for the specimens, which were sprayed by above 4 conditions. As a result, Young’s modulus, and
tensile strength increased with decreasing porosity ratio. In case of tests for residual stress evaluation,
as-sprayed specimens have small tensile residual stresses. After thermal exposure, residual stresses
shifted to compressive.
Three Dimensional Monte Carlo Simulation of Grain Growth in HAZ of Stainless Steel SUS316
Authors: Wei Yan Hong , Xu Yan Li , Dong Zhi Bo , Xiao Ji Lin
Published: March 2009

The stainless steel SUS316 grain growth process in heat affected zone (HAZ) of gas
tungsten arc welding (GTAW) process is studied with Monte Carlo (MC) simulation. The heat
transfer and fluid flow model provides the thermal history and thermal distribution of the
weldments for MC grain growth simulation. The grain growth evolution is simulated both in
isothermal and in HAZ environment. The simulating results show clearly the “thermal pinning”
effect on the grain growth evolution in HAZ compared with the isothermal results.
Microstructure in the Interface between CVD Diamond Thick Film and a Ag-Cu-Ti Braze Alloy
Authors: Sun Feng Lian , Gu Feng , Zhao Zhi Li , Xian Heng Ze
Published: March 2009

CVD diamond thick film was brazed to cemmented carbide using a Ag-Cu-Ti active filler
metal. The brazing process was performed in a vacuum furnace under different processing condition.
The interfacial microstructure and characterization between diamond and Ag-Cu-Ti filler metal
were studied by SEM, EPMA and EDX. The morphology and distribution of new compound are
shown for the first time (Figs). Results illustrate that a small amount of new compound TiC, TiCu
compound exist in the interface. TiC layer exists in the interface and it's thickness is variational
with the varying of processing condition such as peak heating temperature, keeping time and so on.
New compound TiC accretes with the surface atoms of diamond in a special section, and particular
orientation relationships are occasionally observed by examining the fracture section. TiCu layer
near TiC exists in the interface. It is worth notice that too much TiC and TiCu in interface could
weaken join strength because TiC and TiCu are brittle.
Microstructure and Mechanical Properties of Simulated Heat Affected Zone of an Ultrafine Grain Steel Laser Weld
Authors: Wang Qing Feng , Shang Cheng Jia , Wang Ya Nan , Chen Wayne
Published: March 2009

In this paper, the very rapid thermal cycles imposed on an ultrafine grain steel plate were
successfully simulated using a Gleeble™ simulator. The simulated heat affected zone was obtained
suitable for Vickers hardness and impact toughness examination of laser weld that originally bear a
narrow zone with high hardness gradient. Effect of preheat treatment on the mechanical behavior of
laser HAZ was estimated. It was indicated that the simulated HAZ was composed of fine martensitic
ferrite laths with average width in 65nm and 175nm in the case of preheat at 200°C and not,
respectively. The laths were cramped by retained austenite film within the prior austenite grain with
average size of 9.5 and 6.5μm, much less than that of base metal. The impact toughness of HAZ was
improved by laser thermal cycle comparing to that of base metal, and there is no obvious
brittle-ductile transition under temperatures from -80°C to 20°C. Preheat treatment of steel plate prior
to laser welding resulted in an effective reduction of the maximum hardness and alleviation of the
hardness gradient in the weld.
Evaluation of Local Tensile Properties of Bi-Metallic Weld Joints by Small Tensile and Ball Indentation Tests
Authors: Kim Jin Won , Park Jong Sun , Kim Jong Sung , Jin Tae Eun
Published: March 2009

This study performed tensile test using small-size flat specimen and ball indentation test at
room temperature to characterize the local tensile properties of bi-metallic weld joints. The weld
specimens used were fabricated by joining between SA508 Gr.3 ferritic steel and Type 316 stainless
steel with Alloy 82 buttering on the ferritic steel side and Alloy 82/182 weld metal. The test results
showed that yield stress (YS) of weld metal was slightly higher than that of Type 316 and smaller
than that of SA508 Gr.3, and ultimate tensile stress (UTS) of weld metal was similar as those of Type
316 and SA508 Gr.3 base metals. Also, the values of YS and UTS of buttering layer (Alloy 82) were
nearly same as those of weld metal. Heat-affected-zones (HAZs) showed higher YS and UTS values
compared to their base metals. Especially, the strengths of SA508 Gr.3 were significantly higher than
those of surrounding materials. Also, it was known that the ball indentation test reasonably measured
the local YS and UTS of bi-metallic weld joints.
Assessment of a New Semi-Rigid Model in Steel Beam-to-Column Connections
Authors: Yang Cheol Min , Kim Young Moon , Ko Nag Ho , Hong Dong Pyo
Published: March 2009

This paper proposes a new semi-rigid detail used high-strength bolts for use in
earthquake resistant structures. These specimens were single-side beam-to-column assemblies that
are representative of exterior beam-to-column connections, and they were composed of identical
beam and column but had the different connection details, respectively. All beam-to-column
assembly required no welding. Specimen 1 (TSD) was standard Top-Seat-Double-web-angle but
specimen 2 (MTSD) was made by modified shape. Two high-strength bolted steel semi-rigid
connections were prepared and cyclic load was applied to each test specimen using displacement
control. The cyclic load and displacements, moment-rotation plots, and the deformation pattern or
failure modes for all the test cases are presented. The strength, stiffness, energy, and ductility of the
tested connections are compared to each other.
A New Strategy for In-Service Inspection of Nuclear Piping Considering Piping Failure Frequency
Authors: Choi Sun Yeong , Choi Young Hwan
Published: March 2009

The current in-service inspection (ISI) strategy for the nuclear piping in many countries
consists of both the code requirements such as ASME B & PV Code Sec. XI and the country-specific
regulatory requirements, so called as the enhanced ISI. The enhanced ISI reflects the operating
experience of piping failure, while the ASME Code Sec. XI requirement is based on random
sampling for the inspection points. In this study, a new strategy for ISI of nuclear piping was
proposed based on piping failure frequency. This strategy basically reflects the operating experience
because the piping failure frequency is based on the piping failure database. The new concept of
minimum inspection rate was also introduced in this new ISI strategy. As pilot study, the new ISI
strategy was applied to the Class 1 piping system such as reactor coolant system and safety injection
system of Ulchin Unit 5 which is the 1,000 MWe Korean Standard PWR. The results from the
proposed new strategy were compared to those from the ASME Code Sec. XI. The results show that
the new ISI strategy reasonably reflects the operating experience. The results also show that the
concept of the minimum inspection rate can compensate the unbalance in the number of inspection
points between the very large differences in the piping failure frequency.
Tearing Energy for Crack Growth at the Bonds of Cylindrical Rubber Bushes Subjected to Axial Shear
Authors: Yang Xiao Xiang , Li Xiao Fang
Published: March 2009

We applied the fracture mechanics approach and the nonlinear finite element method to
the analysis of interfacial failure in cylinder rubber bush bonded on their outer and inner curves
surfaces to rigid metal cylinders. The fracture parameter, tearing energy for rubber bushes was
calculated using global energy change. The contact of interfacial crack during deformation was
considered. The analyses for initially small cracks and relatively large cracks growing downwards
disagree with the previous linear solutions. The variation tearing energy for cracks growing
upwards is consistent with the existed results except a small range of crack length at the bottom end,
where negative tearing energies exist which indicates a small crack is unexpected to initiate.
The Effect of Hybrid Surface Modification; Combination of Fine Particle Bombardment Treatment and Nitriding, on Fatigue Properties of Steel
Authors: Kikuchi Shoichi , Komotori Jun , Kameyama Yutaka , Fukazawa Kengo
Published: March 2009

In order to clarify the effects of the hybrid surface modification process; a combination of
Fine Particle Bombardment (FPB) treatment and nitriding, on the fatigue properties of AISI 4135
steel (stress concentration factor: α=2.36), high cycle fatigue tests were carried out with a rotational
bending machine at room temperature. Observations of fracture surfaces and measurements of
hardness and residual stress distributions were carried out to investigate the fracture mechanism and
fatigue strength. It was revealed that treating process sequence did affect residual stress distributions.
Compressive residual stress generated at the surface of FPB treated specimen after nitriding was
higher than that of the one FPB treated before nitriding. It was clarified that the higher the specimen
hardness was, the higher compressive residual stress was generated at the surface. Therefore, FPB
treatment after nitriding increased the fatigue strength of steel.
Synthesis and Characterizations of Nanocubes, Monodispersed Nanocrystals and Nanospheres of Au
Authors: Yang Ming , Zhou Guo Qing , Zhao Jiang Guo , Li Zhan Jun
Published: March 2009

Nanocubes, monodispersed nanocrystals and nanospheres of Au have been prepared by
a simple reaction between HAuCl4·4H2O, NaOH and NH2OH·HCl in the presence of gelatin. The
role of gelatin and the affection of pH in producing the nanoparticles of Au were discussed. The
products were characterized by X-ray powder diffraction, transmission electron microscopy, and
UV-visible absorption spectroscopy. The sizes of the monodispersed nanocrystals of Au were
estimated by Debye-Scherrer formula according to XRD spectrum.
Effects of Nitrogen Implantation on the Bonding Strength of Porcelain Fused to Pure Titanium
Authors: Xie Wei Li , Zhong Zhao Wei , Li Chang Cheng , Wen Guang Wu
Published: March 2009

The present study investigates the effect of nitrogen implantation on the surface of pure
titanium on the bonding strength of porcelain and titanium. A series of pure titanium specimens are
cut and divided into nitrogen implantation group. The TiN is found in the implantation layer. The
bending strength of porcelain-titanium is reinforced after titanium is nitrided.
Wavelet Analysis of Elastic Wave for Wall Thinned Inconel 690 Tube
Authors: Ahn Seok Hwan , Seong K.Y. , Kim Jin Wook , Nam Ki Woo
Published: March 2009

The bending moment test used by the specimens with partial and circumferential wall
thinning was carried out to obtain the AE signal. The time-frequency analysis method for the
investigation of the frequency characteristics of the AE signal was applied. The results of the
wavelet analysis were compared with those of the bending moment test for the structural integrity
of tube. The result of the frequency characteristics by applying wavelet analysis method and
dropping ball test was presented similarly to those of bending moment test. It is considered that this
simple method with combination of dropping ball test and wavelet analysis is very useful scheme
for investigating the structural integrity.
Model Based Online Diagnosis of Rotating Machinery Structural Damage
Authors: Yao Hong Liang , Zhao Chun Yu , Sun Wei , Wen Bang Chun
Published: March 2009

Structural damage often happens in rotating machinery such as steam engines, aircraft
engines, and compressors due to the high-speed rotating of the shaft. The most common structural
damages in rotating machinery are rotor shaft crack, rotor to stator rub, and bolts looseness and so
on. In the present paper, the model based identification method is used to detect single structural
damage such as crack, rotor to stator rub, pedestal looseness, and also, coupling fault such as rotor
to stator rub and crack, crack and pedestal looseness. Utilizing the characteristic that equivalent
loads of rub forces are internal forces, and the equivalent loads of the crack are external moments,
the coupling faults of crack and rub-impact and crack and pedestal looseness are analyzed and
exampled. The merit of the method is that it is an online diagnosis method, which provides early
warning of machine failure. Theoretical simulation and laboratory testing are conducted to validate
the method.
Experimental Investigation on Residual Stress of Model S1100 of Crankshaft Chamfer Based on XRD
Authors: Zhang Yong Kang , Kong De Jun , Lu Jin Zhon , Feng Ai Xin , Ren Xu Dong , Zhang Xing Quan
Published: March 2009

Residual stresses of model S1100 of crankshaft chamfer were measured by the
technology of XRD. The distributions of residual stresses under mechanical peening, mechanical
rolling and isothermal quenching are measured, and the tests of fatigue life were conducted. The
results showed that the distribution of residual stress by machining in the crankshaft chamfer is
complicated, which is at the tensile-compressive status, and it is one of the main factors to affect
fatigue life of the crankshaft; isothermal quenching improves the distribution of residual stress, and
tensile stress of the crankshaft chamfer is changed into the compressive stress, which may satisfy
the requests of fatigue testing for 5 × 106 cycles. Although the mechanical rolling improved the
residual stress distribution in the chamfer linked with the crank, tensile stresses in the chamfer
connected with the linkage also increase, which influences the service life of the crankshaft.
A Crack in an Electrode Layer between Two Dissimilar Piezoelectric Materials
Authors: Beom Hyeon Gyu , Kim Y.H. , Yoon C.K. , Cho Chong Du
Published: March 2009

A crack on the conductive interface between two dissimilar piezoelectric ceramics under
electromechanical loading is investigated. The closed form of the singular crack tip fields for the
interface crack is derived here using an analysis based on analytic functions. It is shown that the
interfacial crack-tip field consists of a pair of oscillatory singularities. A closed form of the solution
for a finite crack on the conductive interface between dissimilar piezoelectric media is also derived.
Infrared Thermal Image Study on Failure of Granite with Hole
Authors: Tan Zhi Hong , Tang Chun An , Zhu Wan Cheng
Published: March 2009

The changing behavior for infrared thermal image omen of the rock with fracture is
essential for the geotechnical engineering. In order to study the behavior, the infrared thermal
images for the failure process of rock with hole are carried out. The size of the rock sample is
20cm×10cm×2cm with hole at the center of the sample and the diameter of the hole is 1cm.
Considering the fact that sample will effect the results of the observation for infrared thermal image
during the experiment, the laminated granite sample was used to replace the cylinder or cuboid
sample. The achieved results under uniaxial compression indicate that intensity of the micro
ruptures have a close relation with the thermal effects. When the main fractures happen, there is a
strip of high temperature that will appear at the destructed local area. During loading process, the
abnormity of infrared temperature has two kinds of behaviors as follows: (1) temperature rises and
falls alternately, rises before the fracture; (2) temperature falls slowly at beginning, and then rises
slowly, then rises quickly before the fracture appears. Even for the same rock sample, the behaviors
of the infrared phenomenon may be different during failure.
Improvement of Crack Detection Probability by Using Magnetic Camera and Image Processing
Authors: Choi Se Ho , Hwang Ji Seong , Jun Jong Woo , Lee Jin Yi , Kim Cheol Woong
Published: March 2009

Magnetic camera consists of magnetic source, arrayed small magnetic sensors, magnetic
lens, analog-to-digital converter and interface, computer and monitor. The quantitative magnetic field
around crack and its processed results could be obtained by using magnetic camera, and the crack
could be inspected and evaluated quantitatively. In addition, the magnetic camera has to uphold with
large lift-off to protect sensors from weak environment such as high temperature and mechanical
vibration. However, the sensor sensitivity would be decreased when the lift-off was increased.
Correspondingly, the improved techniques are necessary for increasing sensitivity of magnetic
camera and probability of crack detection at the large lift-off. This paper proposes an image
processing method, which separates a global full scale to the several regions and repeats shadings in
each region, to increase a crack detection probability in the magnetic camera images such as ∂B/∂x
and ∂2B/∂x∂y.
Development of Numerical Analysis Software for the NDE by Using Dipole Model
Authors: Lee Jin Yi , Jun Jong Woo , Hwang Ji Seong , Lee Se Hoon
Published: March 2009

The magnetic field distribution around a crack can be calculated more easily and quickly by
using a dipole model than finite element method (FEM). This paper reports the development of
numerical analysis software that uses an improved dipole model to analyze the magnetic field around
cracks. The preprocessor in this software includes the crack formation software, which can distribute
the magnetic charge per unit area, m, on the crack section area. Also the lift-off, measurement area
and sensor interval, and magnetization direction can be considered in the preprocessor. Also, the
postprocessor presents functions, such as the natural magnetic field distribution and ∂B/∂x, ∂B/∂y, as
results. Also, the physical characteristics of the magnetic optical sensor and the Hall sensor are
included in the postprocessor, and the magnetic field distribution can be changed to optical intensity
and electrical signal distribution. The experiment results, which are obtained by using the magnetic
camera on the crack, are compared with analysis results obtained by using the dipole model analysis
software.
An Experimental Investigation of Interface Fracture Characteristic of APS Thermal Barrier Coating System under Bending at 1000 °C
Authors: Mao W.G. , Dai C.Y. , Zhou Yi Chun , Liu Q.X.
Published: March 2009

This paper investigated the thermo-mechanical bending failure characteristic of air
plasma-sprayed (APS) thermal barrier coating (TBC) system at 1000 oC by three-point bending test.
A through-width surface pre-crack on the centre surface of the top ceramic coating (TC) in TBC
sample was firstly designed and made by air plasma spraying technology. The fracture characteristic
and spallation phenomena of the TBC were investigated under bending test in air at 1000 oC. The
effects of constant displacement rate, span width of bending equipment and thermal aging time on
the thermo-mechanical bending failure of the APS TBC system were slight at 1000 oC. Using SEM
observations and EDX analysis, the interface cracks initiation, propagation and coalescence were
discussed in detail. Furthermore, the fracture surface located within the TBC close to the TBC/TGO
interface for all APS TBC samples under bending at 1000 oC.
Analysis of Stress Intensity Factors of a Planar Rectangular Interfacial Crack in Three Dimensional Bimaterials
Authors: Noda Naoaki , Xu Chun Hui
Published: March 2009

In this study, a rectangular interfacial crack in three dimensional bimaterials is analyzed.
First, the problem is formulated as a system of singular integral equations on the basis of the body
force method. In the numerical analysis, unknown body force densities are approximated by the
products of the fundamental density functions and power series, where the fundamental density
functions are chosen to express a two-dimensional interface crack exactly. The calculation shows
that the present method gives smooth variations of stress intensity factor along the crack front for
various aspect ratios. The present method gives rapidly converging numerical results and highly
satisfied boundary conditions throughout the crack boundary. It is found that the stress intensity
factors K1 and K2 are determined by bimaterials constant e alone, independent of elastic modulus
ratio and Poisson's ratio.