bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue Crack Growth Characteristics and Effects of Testing Frequency on Fatigue Crack Growth Rate in a Hydrogen Gas Environment in a Few Alloys
Authors: Kawamoto Kyohei , Oda Yasuji , Noguchi Hiroshi
Published: March 2009

In order to investigate the hydrogen effect on fatigue crack growth (FCG) behavior in a few
kinds of practical alloys; austenitic stainless steels (solution-treated metastable type 304 and stable
type 316L), an aluminum alloy (age-hardened 6061) and a low carbon steel (annealed 0.13%C-Fe),
FCG tests were carried out in hydrogen gas and in nitrogen gas. The FCG rates of these materials are
enhanced by hydrogen, though the acceleration degrees are different. A crack grows across grains by
slip-off in 316L stainless steel and in age-hardened 6061 aluminum alloys even in hydrogen. Faceted
area increases in 304 stainless steel and in low carbon steel in hydrogen. In 304 stainless steel, the
ratio of facets to the entire fracture surface was not so large. Thus, the FCG rate is not significantly
affected through the facets in 304 stainless steel. In low carbon steel, facets were increased
considerably, though a crack grows step by step or after a large number of loading cycles even along
grain boundaries. Anyhow hydrogen enhances the FCG rate of these materials through the influence
on slip behavior. Based on above-mentioned results, the effect of loading frequency on FCG rate in
hydrogen of the age-hardened 6061 aluminum alloy was also investigated. The FCG rate increases as
the testing frequency decreases, though the FCG rate in hydrogen shows the tendency to saturate.
The Optimization of the Isothermal Transformation Dwell of the ADI Obtained at Transformation Temperature of 380 °C
Authors: Hanzlíková Klára , Vĕchet Stanislav , Kohout Jan , Zapletal Josef
Published: March 2009

The structure of austempered ductile iron (ADI) matrix and consequently its mechanical
properties are influenced by the heat treatment conditions, above all by the temperature and dwell
length of isothermal transformation. The paper is focused on deeper understanding the interrelation
between matrix mixture composition and static mechanical properties of ADI in dependence on the
isothermal transformation dwell. Practical aim of the paper is to find the optimal isothermal
transformation dwell range for ADI isothermally transformed at the temperature of 380 °C with
emphasis on the level of static mechanical properties in tension. Microstructure and mechanical
properties changes that proceed during isothermal transformation are observed and evaluated for the
transformation dwells of 2, 5, 10, 25, 60, 120, 270, and 540 minutes.
Evolution of Microstructure and Mechanical Properties of HSLA Strip Steel after Cold Rolling and Annealing
Authors: Janošec Marcel , Schindler Ivo , Vodárek Vlastimil , Místecký Emerich , Růžička Martin
Published: March 2009

A large testing programme of a strip steel HSLA grade, microalloyed by vanadium, titanium
and niobium, was conducted. The experiment was based on combination of cold rolling, recrystallization
annealing, mechanical testing, metallographic examinations and TEM analysis. Flat
samples with thickness 3.9 mm were rolled in several passes with the total height reduction 5 to 75
%. Afterwards the laboratory mill products were annealed in the vacuum furnace with the protective
gas atmosphere consisting of N2+H2. The annealed samples underwent the mechanical testing. The
gained results – hardness, yield stress, tensile strength and their ratio, as well as elongation, were
summarized in graph in dependence on relative height reduction before annealing.
It was confirmed that by a suitable combination of size of previous cold deformation and parameters
of the following recrystallization annealing it is possible to influence a complex of mechanical
properties of particular strips. Particular trends of strength and plastic properties correspond to each
other and they may be utilized for optimization of terms of heat treatment of the investigated HSLA
steel in a cold rolling mill. These trends are caused by structure-forming processes (recrystallization,
grain coarsening, changes of the state of precipitates) which were documented by micrographs.
Effect of Sc and Zr Additions on Microstructure and Mechanical Properties of Conventional Cast and P/M Aluminium
Authors: Kolář M. , Očenášek Vladivoj , Uhlíř J. , Stulíková Ivana , Smola Bohumil , Vlach Martin , Neubert V. , Šperlink K.
Published: March 2009

The influence of plastic deformation and heat-treatment on the precipitation of Al3(Sc,
Zr) particles and the effect of these precipitates on hardening and softening processes of dilute
ternary Al-0.2wt.%Sc-0.1wt.%Zr alloy was investigated. Behaviour of two differently prepared
alloys (mold cast and prepared by powder metallurgy – PM) was investigated in as-prepared and in
cold rolled state. Both alloys exhibit the same peak age hardening, PM one reaches it already during
extrusion at 350°C. Both cold rolled alloys are highly resistant against recovery, which proceeds
without rapid hardness decrease at high temperatures. Evolution of hardness agrees well with that of
resistivity and with TEM observation.
Changes in Fracture Micromechanism with Increasing Reinforcement Volume Fraction in Glass Matrix Composite
Authors: Řehořek Lukáš , Chlup Zdeněk , Dlouhý Ivo , Boccaccini Aldo Roberto
Published: March 2009

Fracture behaviour and mechanical properties are the key features when a material for
given application is supposed to be selected. Advanced glass ceramics composites are perspective
structural materials for many applications due to their low production expenses and satisfactory
properties even at elevated temperatures. Borosilicate glass matrix composite reinforced by alumina
platelets was investigated to describe toughening mechanisms and their changes in a wide range of
temperatures (from room temperature up to glassy transition temperature Tg). The dissipation of
energy by bridging and/or deflection of propagating crack by alumina platelets uniformly dispersed
in the glass matrix were the main toughening mechanisms observed. The alumina platelets have a
higher ability to deflect propagating crack in comparison with spherical or rectangular particles
having the same volume. Three and four point bend test for Young’s modulus and flexural strength
determination was used. Fracture toughness determination was conducted using chevron notch
technique. More than 100% increase of fracture toughness was observed when 30% of alumina
platelets were added in to borosilicate matrix.
Solute and Temperature Effects on the Strain Hardening Behaviour of Mg-Zn Solid Solutions
Authors: Cáceres Carlos H. , Blake A.H.
Published: March 2009

The Kocks-Mecking method of analysis is applied to solid solutions of up to 2.6 at.% Zn
to separate the contributions to the alloys’ strain hardening rate from dislocations storage, solute in
solution, and twinning, for temperatures between -50 °C (273 K) and 200 °C (473 K). Athermal
storage of dislocations seems to account for the largest share of the strain hardening rate for both the
pure metal and the solid solutions at or below room temperature. Solute in solution does not
increase the strain hardening rate over that of pure Mg, although it delays the onset of dynamic
recovery, especially for the higher alloys, presumably due to short range order. Twinning remains a
very important deformation mechanism for the pure metal and the dilute alloys up to 200 °C.
Numerical Simulation of Heat Evolution of Eco-Friendly Blended Portland Cements Using a Multi-Component Hydration Model
Authors: Wang Xiao Yong , Lee Han Seung , Park Ki Bong
Published: March 2009

With the development of concrete industry, the necessity for utilizing waste materials and decreasing overall energy consumption is becoming increasingly obvious. Fly ash and granulated blast-furnace slag, which are used as blends of Portland cement, are waste materials produced in electric and energy industry, and concretes made with them can have properties similar to ones made with pure Portland cement at lower cost per unit volume. By using blended Portland cement, both ecology benefit and economic benefit can be achieved. Due to the pozzolanic reaction between calcium hydroxide and blended components, compared with ordinary Portland cement, hydration process of blended Portland cement is more complex. In this paper, based on a multi-component hydration model, a numerical model which can simulate heat evolution process of blended Portland cements is built. The influence of water to cement ratio, curing temperature, particle size distribution of cement paste and blended Portland material, and cement mineral components on heat evolution process is considered. The prediction result agrees well with experiment result.
Preparation and Characterization of High Compressive Strength Geopolymeric Monoliths Using Silica Waste
Authors: Son Se Gu , Hong Seong Yeob , Kim Young Do
Published: March 2009

The goal of the present work was investigated development of ET(Environmental
Technology) industrial geopolymer materials from mixture Silica Mine Waste(SW) and ground
granulated blast furnace slag(GGBFS) and alkali activator solution(sodium silicate) by the
Geopolymer Technique at ambient temperature. As for the synthesis of geopolymeric monoliths,
four different GGBFS content(10wt%, 20wt%, 30wt%, 40wt%) and three types of
GGBFS(GGBFS-1(blaine 4,000cm2/g), GGBFS-2(6,000cm2/g), GGBFS-3(8,000cm2/g)) are
investigated to obtain the optimum synthesis condition based on the high compressive strength. The
weight ratio between the alkali activator solution and dry mix(SW and GGBFS) were 0.25 and 0.3,
respectively. The results showed that geopolymeric monolith containing 30wt% GGBFS exhibits
higher compressive strength and increased along with increase of GGBFS blaine. The compressive
strengths of GGBFS-1, GGBFS-2 and GGBFS-3 are 66.7MPa, 83.1MPa, 94.1MPa, respectively.
Additionally, scanning electron microscope (SEM) techniques are used to characterize the
microstructure of the geopolymeric monoliths. SEM observation shows that it is possible to have
amorphous aluminosilicate gel and calcite forming simultaneously within monoliths. XRD patterns
indicate that geopolymeric monolith is composed of amorphous aluminosilicate phase and calcite
and quartz.
Comparison of Porous Ceramic Materials with Low Thermal Expansion Coefficient Prepared with SiC and Black-Al2O3
Authors: Juárez-Ramírez Isaías , Matsumaru Koji , Ishizaki Kozo , Torres-Martínez Leticia M.
Published: March 2009

Porous ceramic materials with low thermal expansion (LTE) at room temperature were prepared by heating a mixture of SiC or black-Al2O3, vitrified bonding material (VBM) and LiAlSiO4 at temperatures from 850°C to 1100°C. The mixture was prepared in adequate proportions to obtain a material with LTE according to previous works made in our laboratory. It was observed that a change in temperature provoked the formation of a new phase, LiAlSi3O8, which appears above 900°C. The presence of this new phase did not affect the thermal expansion value, keeping LTE at room temperature. All compounds showed around 40% of porosity, and Young’s modulus values of 30 GPa using black-Al2O3 or SiC. X-ray diffraction analysis (XRD) revealed that above 900°C the phase LiAlSi3O8 starts to appear as a consequence of the melting of VBM, which is reacting with the raw materials. SEM micrographs showed the presence of SiC or black-Al2O3 grains joined by VBM, which is acting as a bridge between them.
High Temperature Oxidation of WC-CrN Superhard Nanocomposite Film
Authors: Lee Hwa Shin , Lee Dong Bok
Published: March 2009

The high-temperature oxidation resistance of the WC-CrN superhard nanocomposite films was studied at 600 and 700oC in air. The oxidation of the film resulted in the formation of volatile species such as the evolution of carbon probably as CO or CO2, evolution of nitrogen from the film, and the formation of W-oxides. The scale formed was prone to cracking and spallation.
Corrosion Resistance of TiAlN/ZrN and TiCrN/ZrN Multilayers during Heat Treatment
Authors: Song Dong Hwan , Lee Jong Kook , Seo Dong Seok , Yang Gon Seung
Published: March 2009

Titanium-based nitride coatings on cutting tools, press molds and dies can prolong their life
cycle because of superior corrosion and oxidation resistance of coatings. In this study, TiAlN/ZrN and
TiCrN/ZrN multilayer coatings were prepared by R.F magnetron sputtering, and microstructural
evolution and corrosion resistance of the coatings were investigated during heat treatment. The
TiAlN/ZrN and TiCrN/ZrN multilayer coatings were degraded by heating up to 600 oC with
formation of oxides particles on the surface. During the heat treatment, the TiCrN/ZrN and
TiAlN/ZrN multilayer coatings showed the lowest corrosion current density and the highest
polarization resistance at temperature range of 400 oC and 500 oC. Consequently, the TiAlN/ZrN and
TiCrN/ZrN multilayer coatings showed good corrosion resistance at temperature range of 400°C and
500°C during heating.
Test Method for Skin Damage of Titania Photocatalyst Nanoparticles In Vitro
Authors: Watanabe Eiji , Fukaya Mitsuharu , Nishizawa Kaori , Miki Takeshi , Taoda Hiroshi
Published: March 2009

Nanoscale TiO2 is widely used in consumer products like sunscreen and cosmetics. The
establishment of damage evaluation test method was attempted to examine the potential
neurotoxicity of nanoscale TiO2 to human body skin in vitro model. The emergence amounts of
carbon dioxide, which was expected one of the generation products from the skin according to the
titania photocatalyst nanoparticles activity under UV / visible light radiation, were identified and
measured by the gas analyzer. It was found that it could evaluate the degrees of damage to skin with
the photocatalysts activity by using the new evaluation test method considered.
The Mechanical Properties of AlN/BN Laminated Ceramic Composites
Authors: Zhang Tao , Jin Hai Yun , Wang Yong Ian , Jin Zhi Hao
Published: March 2009

AlN/BN laminated ceramic composites were fabricated using tape-casting and
hot-pressing by optimizing the designs of the structure and geometry of AlN/BN laminated ceramic
composites. The results showed that the fracture toughness and bending strength for AlN/BN
laminated ceramics reached 9.1MPa.m1/2 and 378MPa respectively. The fracture toughness is two
times higher than that of AlN monolithic ceramics. The excellent fracture toughness of AlN/BN
laminated ceramics could be mainly attributed to crack deflection, delaminating, branching, parallel
propagation and crack laminate pilling out at the AlN/BN weak interface.
Anisotropy Enhancement in Co Granular Multilayers by Capping
Authors: Bartolomé Juan , Luis F. , García L.M. , Bartolomé F. , Petroff F. , Deranlot C. , Wilhelm F. , Rogalev A. , Bencok P. , Brookes N.B.
Published: March 2009

The effect of capping with Cu, Au and Pt of an array of Co nanoparticles is revised. The magnetic surface anisotropy KS was found to be the dominant contribution to the effective anisotropy Keff of the particles. Recent X-ray Magnetic Circular Dichroism (XMCD) measurements show that there is hybridization between the 3d Co electrons and the d and 4p electrons of the capping metal. By comparison to the mechanisms which give rise to the surface anisotropy in thin films, it is argued that this hybridization governs the modification of KS, and hence, of Keff.
Neutron Diffraction Analysis of Stresses in an In-Plane Biaxially-Fatigued Stainless Steel Sample of Cruciform Geometry
Authors: Taran Yu. V. , Balagurov A.M. , Schreiber Jürgen , Korsunsky Alexander M.
Published: March 2009

An ex-situ in-plane biaxial low cycle fatigued sample of cruciform geometry made from
austenitic stainless steel AISI 321 H was studied with the help of neutron diffraction strain scanning
and also in-situ uniaxial loading using a stress rig on the FSD stress-diffractometer at the IBR-2
pulsed nuclear reactor (Dubna). The objectives of the experiment were to measure the macroscopic
and microscopic residual stresses, crystallographic phase composition and the mechanical
characteristics of the alloy under fatigue conditions. To the best of our knowledge, no neutron
diffraction investigations of structural alloys subjected to biaxial loading have previously been
reported. Experimental data interpretation and analysis are presented and discussed.
First Results of the DITO-Experiment at the HARWI II Beamline at GKSS/DESY
Authors: Hasse Bernd , Rahn Helene , Odenbach Stefan , Beckmann Felix , Reimers Walter
Published: March 2009

At the HARWI II beamline at the GKSS outstation at DESY a new experiment for
position sensitive diffractometry and tomography called DITO was built and commissioned this
year. Due to the available high energy synchrotron radiation with photon energies up to 100 keV it
is possible to investigate the bulk of metallic samples of a few mm thickness with both methods.
The diffractometry detector allows the investigation of the phase composition as well as phase
sensitive determination of residual stresses with a spatial resolution of 6 μm while the tomography
detector can either measure a whole tomogram in high resolution mode with a spatial resolution of 2
μm within 3 to 4 hours or in high speed mode recording a whole tomogram within 15 seconds with
a spatial resolution of 40 μm.
Problems in the Averaging of Neutron Diffraction Stress Data from Round-Robin Campaigns
Authors: Wimpory Robert C. , Ohms Carsten , Hofmann Michael , Schneider Rainer , Youtsos A.G.
Published: March 2009

In recent years the use of a special Bayesian approach on averaging ‘round-robin’ residual
stress data has been implemented. This averaging approach is useful in that it copes with the
situation where systematic errors have occurred in one or more of the measurements and thus
diminishes the influence of these particular ‘wrong value’ outlier data points. The analyses not only
take into account the measurand value, but also the uncertainties associated with each measurand. It
should deal with data that may contain individual members with uncertainties larger than the stated
error and assumes that the quoted error bar is only a lower bound on the uncertainty. This work
shows what could happen when there is a ‘strong mismatch’ in uncertainties when averaging over a
limited amount of data. It has been observed that in a case where there are few data points (for
example 5 or less), a strong bias can occur towards data points with a relatively small quoted
uncertainty compared to other data points with larger quoted uncertainties. A ‘mismatch’ in
uncertainty quotation can arise when averaging very good data with poorer data or when averaging
with data obtained from other measurement techniques. This effect is demonstrated in this work by
using fictitious data and also based on the example of real measurement data obtained by neutron
diffraction.
Through-Thickness Residual Stress Measurement in Metal and Ceramic Spray Coatings by Neutron Diffraction
Authors: Luzin Vladimir , Valarezo A. , Sampath S.
Published: March 2009

Thermal and cold spraying encompasses a great variety of techniques for deposition of
fully or partially molten or cold particles of material to produce coatings with a specific
microstructure and properties for the purpose of surface enhancement. Among the many factors
influencing sprayed coating integrity, residual stress is very important since it will be the driving
force for possible crack propagation and consequent coating failure. The very complex physical
processes occurring during coating deposition make first principles treatment difficult. A number of
empirical models have been proposed to predict and describe quantitatively the stress distribution in
the coating/substrate system. However, there are a limited number of experimental measurements
on through-thickness stress distribution and for only a few materials and few spraying techniques,
to validate any model and to define its area of applicability. Several metal and ceramic coatings
produced by different spraying techniques were measured by means of neutron diffraction.
Through-thickness stress profiles were obtained and treated in the frame of the empirical
progressive coating deposition model. The comparison between experimental and simulated results
is discussed.
Analysis of Residual Stress in Laser Welded Aerospace Aluminium T-Joints by Neutron Diffraction and Finite Element Modelling
Authors: Bayraktar Funda S. , Staron Peter , Koçak Mustafa , Schreyer Andreas
Published: March 2009

The residual stress distribution in three laser welded T-joint configurations of aerospace
aluminium alloys were measured using neutron diffraction and FE-simulation was conducted to
compare with the experimental results. A 2 mm thick AA 6013 T6 sheet (as clip) was welded to a
4.5 mm thick and 400 mm wide AA 6156 T4 base plate (as skin of the airframe). In two samples,
the thickness of the plate was reduced in some areas after welding to produce so-called “pockets”
with the purpose of the weight reduction to resemble the fabrication practise in aircraft industry.
The effect of pocketing process, which produced two different geometries around the clip weld on
the residual stress evolution was analysed. In the plain sample (without pockets), residual stresses
were predicted using the SYSWELD finite element software. The strain measurements on the base
plate were performed at three locations; namely, the middle of the weld length (mid-clip), welding
start (run-in) and end (run-out) locations.
In all welded plates, slightly higher longitudinal tensile residual stresses were detected at the midclip
locations, whereas transverse residual stresses were similar for all locations. In the run-out
location, higher longitudinal tensile residual stresses were present than in the run-in location, which
was the case in our previous results on other samples.
The first results of the SYSWELD FE-simulation of the plain sample were compared with
experimental results. The comparison has shown particularly good agreement for the transverse
stresses. Although the simulation yields higher longitudinal tensile stresses than the experimental
results, the stress distributions were very similar.
Nonlinear Bending of the FGM Circular Plates with Temperature-Dependent Properties
Authors: Ma Lian Sheng , Deng Chun Zhi , Ou Zhi Ying
Published: March 2009

Axisymmetric nonlinear bending of the functionally graded circular plates is investigated
in the present work. The material properties of plates are assumed to be graded in the thickness
direction according to a simple power law distribution in terms of the volume fractions of the
constituents, and to be temperature-dependent. Based on the classical nonlinear plate theory, the
governing equations for the problem are derived, and then a shooting method is employed to
numerically solve the equations. Effects of material constant, temperature- dependent properties and
boundary conditions on the nonlinear bending behavior of the FGM plate are discussed in details.
Influence of High Shearing Stress-Induced Strengthen Effect on GF/HDPE Composites
Authors: Dai Guang Ze , Zhou Xian Feng , Dong Li Xin , Wu Sheng Nan , Liu Li Ling , Ni Qing Qing
Published: March 2009

For the short glass fiber reinforced high density polyethylene (HDPE), a high
shearing stress-induced HDPE and MAH functional reaction method was introduced which was
achieved by increasing the twin screw extruder rotation speed during melting extrusion process. The
results show that the graft degree of consequent HDPE-g(b)-MAH product has been increased
from 0.14% of the thermal-induced one to 0.77% by the high shearing stress-induced one when the
rotation speed of the screw increases from 100r/min to 800r/min. Therefore, the mechanical
properties of the GF/HDPE composites are greatly improved, namely, its tensile-strength,
bending-strength and the notch impact absorbed work are increased from 21.43MPa, 15.49MPa and
12.82kJ/m2 to 30.18MPa, 29.72MPa and 19.12kJ/m2 respectively. The corresponding simulations
through the commercial Moldflow soft show a good agreement with these experimental data.
A Study on Constitutive Model and Parameters of Rock Slope Stability
Authors: Yan Zhi Xin , Duan Jian , Jiang Ping , Wang Hou Yu
Published: March 2009

In this paper, taking elastic and plastic characteristics of rock into account, the
authors have studied the relationship between different constitutive models. By
transforming material parameters merely, on the basis of Equivalent Mohr-Coulomb Yield
Criterion, the researchers achieved the application of these relationship in the computer
program-Ansys5.7. They also have discussed the magnitude relationship between the
transformed parameters and the original ones. By analyzing the cases of rock slope with
obvious sliding surface, the researchers proved that it is liable to replace Mohr-Coulomb
Yield Criterion with Equivalent Mohr-Coulomb Yield Criterion. We can use Equivalent
Mohr-Coulomb Yield Criterion to simulate rock material, the results are smaller and more
conservative than the standard ones. Meanwhile, the authors indicate that it is beneficial to
apply Equivalent Mohr-Coulomb Yield Criterion to simulate rock material in rock slope
projects with obvious sliding surface which have accurate standard requirements about
displacement.
Pad Effects on Slurry Flows in CMP System
Authors: Zhang Chao Hui , Zhang Jian Qun
Published: March 2009

Chemical mechanical polishing (CMP) is a widely adopted technique to achieve high level
of global and local planarity required in modern integrate circuit (IC) industries, wherein the pad
properties weigh heavily on the final performance. A preliminary two-dimensional wafer-scale flow
model for CMP is presented considering the roughness, the elasticity, as well as the porosity of the
pad. Numerical simulations were conducted to show the slurry flow features’ variations due to pad
parameters change. The results show that the porosity of the pad is conducive to slurry delivering, and
small porous parameter will lead to prominent increase of load capability, accounting for larger
material removal rate (MRR) whilst the elasticity of the pad has a more complex influence. The rough
surface carries additional fluid in the valleys of the polishing pad thereby provide some chemical
reactions. The model will shed lights on the mechanism of CMP process, which is for a long time
considered as a difficult circle to square.
Application of RFPA2D in Sublevel Caving Mining Extra-Thick Coal Seams
Authors: Nan Hua , Xu Tao , Wei Zhi Dong
Published: March 2009

On the basis of suitable arrangement for the special stress surrounding and parameters
selection, Realistic Failure Process Analysis 2-D (RFPA2D) numerical simulation of extra-thick coal
seams’ displacement and failure is carried out. It’s proved that the numerical simulation results are
consistent with the in-sit measurement results of top coal’s advance supporting stress and deep-hole
displacement. So application of RFPA2D in sub-level caving mining extra-thick coal seams is
reliable. It’s also proved that application of RFPA2D in sub-level caving mining can do great help to
study the nature of top coal’s displacement, fragmentation and failure process of extra-thick coal
seams. As the top coal’s displacement and failure situation under certain circumstance can be
forecasted by RFPA2D numerical simulation, the most suitable top coal thickness under certain
circumstance can be predicted by RFPA2D numerical simulation test, which can do great benefit to
extra-thick coal seams’ safe and high efficient mining.
Analysis and Experiments of Eddy Current Brakes with Moving Magnets
Authors: Shiau Jaw Kuen , Ma Der Ming , Jou Min
Published: March 2009

This paper discusses the magnetic drag force resulting from the relative motion of a
permanent magnet moving along a finite dimensional conducting plate. The image method with
imaginary eddy currents is investigated. Boundary conditions are established to ensure that the eddy
currents vanished at the boundaries of the conducting plate. Magnetic drag force is computed based
on the eddy current distributions using Lorentz force law. A test system is built to demonstrate the
magnetic brakes arose from the electromagnetic interactions.
A FEM Study on Chip Formation in Orthogonal Turning Nickel-Based Superalloy GH80A
Authors: Li Jun Li , Liu Gang , Zhang Dong Jin , Chen Ming
Published: March 2009

The nickel-based superalloy GH80A is a typical difficult-to-cut material. It has been used
in a good many kinds of aeronautical key structures because of its high yield stress and anti-fatigue
performance at high temperature. But selection of cutting parameters in actual machining process
mainly depends on experience and lacks of scientific utterance. In this paper, finite element method
(FEM) was introduced to study the chip formation process when machining nickel-based superalloy
GH80A. By the way of lagrangian finite element approach and material failure, adiabatic shear band
(ASB) and periodic fracture were simulated with the help of former researchers’ studies on the
material constitutive relation. Both the mechanism of adiabatic shearing phenomenon at primary
shear zone and periodic crack in the free surface were analyzed, chip formations under different
cutting parameters were got and compared carefully. The root cause of saw-tooth chip formation
under different cutting speeds was discussed.
Research and Simulation of Influence of Different Pressing Velocity on Powder Metallurgic Products Properties
Authors: Jiao Ming Hua , Wang De Guang , Xie Ting , Yu Jian Wei , Yin Yan Guo , Wu Yu Cheng
Published: March 2009

The warm compaction process is simulated by the finite element analysis software
which is MSC/MARC. The thermal mechanically coupled analysis method is applied based on the
updated Lagrangian Method to simulate powder warm compaction process under different frictional
condition and different strain rate. The influence of different friction condition and strain rate is
researched on the density and the mechanics behavior of powder green. The results indicate that for
cylindrical powder metallurgic products, with the increasing of pressing velocity (namely strain
rate), work hardening of powder is gradually evident, and leads to larger distribution grads of
density and equivalent stress of green. The improvement of friction condition is propitious to reduce
the disadvantage of work hardening and improve the uniformity of distribution of density.
Effect of Scanning Frequency on Temperature Distribution
Authors: Wang Y.S. , Wang Juan Juan , Yang Xi Chen
Published: March 2009

Based on the calculation formulas of heat treatment temperature field of the narrow strip
spot of laser beam passing a scanning rotating mirror, the effect of scanning frequency on temperature
field was analyzed in this study, and the math model of the temperature field with scanning frequency
was derived applying the superposing principle of the temperature field. The value simulation and
figures description were given. The relationship between scanning frequency and temperature
distribution was studied, and the best extent of frequency was given for carbon steel laser quenching
with laser rotating mirror. The value simulation shows that the higher the scanning frequency is, the
more evenly distributed the temperature field gets. At a certain laser power and a certain length of
laser scanning line spot, for non-melting laser heat treatment under the spot, a maximum thickness of
the high- temperature layer can be get at some certain scanning frequency range which depends on
thermal diffusion coefficient of the material.
Research on Closed Die Forging Process of Car Steering Knuckle
Authors: Zhao De Ying , Zhang Lian Dong , Sun Hui Xue
Published: March 2009

Steering knuckle, which has strict requirements with regard to dimensional precision and
quality, is a key component in cars. Conventional plastic forming methods are involved with
intricate procedures and high energy consumptions. Normally, a 40 MN hot die forging press or a
100 KJ electro-hydraulic hammer is required to produce the steering knuckle. Closed die forging,
which is a new precision forming technology developed in recent years, has some virtues, such as
good mechanical properties, easy to form and improving of metal plastic deformation. Aiming at
Jetta steering knuckle in this paper, the technology of two forging steps in one heat is presented.
This technology is mainly composed of precision pre-forging, which is a closed die extrusion with
the extrusion belt, and open finish-forging. The pre-forging process and finish-forging process are
numerically simulated using the FEM software DEFORM-3D. For the closed die extrusion
forming process, which is the key component of the technology, some key problems were
researched, such as the flowing and filling regularity, extrusion-belt length, punch size, punch
movement, lubrication and the relationship between the clamping pressure and the extrusion
pressure. For the finish-forging process, the flowing and filling regularity of the finish-forging
part was studied to verify the correct shape and dimension of the pre-forging part. Numerical
simulation with regard to the pre-forging process shows that the closed die forging can not only
help to form the pre-forging part, but also decrease the extrusion pressure to be less than 8 MN,
extend the mould’s service life and increase the utilization ratio of materials to be more than 75%.
Numerical simulation of the finish-forging process shows that the pre-forging part design is
rational. In addition, the forging experiments were carried out using the dies designed in particular.
The experiments show that the technology is feasible and can markedly improve the mechanical
property of the forging piece.
A Goal Oriented Numerical Simulation Approach for Computing Stress Intensity Factors in Bimaterials
Authors: Xuan Z.C. , Peng J.W.
Published: March 2009

We present a method for computing the stress intensity factors in bimaterials based on the
goal oriented finite element error estimate. The goal oriented analysis focuses on computing the
bounds on the local quantities of interest, e.g. local stresses, local displacements, stress intensity
factors etc, of a structure, and with the bounds obtained on the coarse finite element mesh we can
obtain the quantities of interest with nearly the same accuracy as that obtained on the fine finite
element mesh. In this paper the stress intensity factors in bimaterials are first formulated as explicit
computable linear function of the displacements by means of the two-points extrapolation method.
Then the goal oriented finite element method is used to compute the lower and upper bounds on the
stress intensity factors, and the average of the bounds is considered as a prediction of the stress
intensity factor. At last, the stress intensity factors, 0 K and r K , in bimaterials are computed with the
proposed method to show its efficiency.
Microstructures of Rapidly Solidified Hypereutectic Al-Si Alloy with Low-Titanium Content
Authors: Wang Ai Qin , Xie Jing Pei , Liu Zhong Xia , Li Ji Wen , Wang Wen Yan , Yan Shu Qing
Published: March 2009

In the present work, rapidly solidified alloys strips with Al-0.24Ti and Al-21Si-0.24Ti(in
wt.%) were prepared by single roller melt-spinning method. The microstructures, phase and
morphology characteristics of the resultant strips were characterized by means of scanning electron
microscopy (SEM),transmission electric microscopy (TEM) and XRD technique. The results show
that the grains have been refined after rapid solidification processing, and the micro-nanocrystalline
grain are formed. The morphology characteristics can be changed. The microstructures of Al-0.24Ti
alloys strip are micro-nanostructure α-Al solid solutions which are similar with granular or nodular,
the corresponding SAD pattern is rings, it presents characteristic of polycrystal; Compared with
equilibrium solidification, the microstructures of hypereutectic Al-Si alloy are changed obviously.
They are composed of primary micro-nanostructure α-Al supersaturated solid solution and
nanocrystal granular (α+Si) eutectic which set in the supersaturated solid solution. The nucleation and
growth of primary silicon are suppressed and primary silicon can not precipitate, meanwhile, α-Al
phase is nucleated which prior to eutectic, therefore the microstructures become into the metastable
state. The mechanism of the formation for microstructures of melt-spinning alloys has also been
discussed.
Thermal-Mechanical Analysis of Metal Forming Based on Meshfree Method
Authors: Hua Guang Ru , Wen Hong Yu , An Li Qiang
Published: March 2009

A thermal-mechanical analysis of metal forming based on meshfree method is performed.
During the coupled analysis, two independent sub-systems, i.e. the velocity field and temperature
field are considered. The effect of deformation on temperature field is added into the temperature
solution by the vector of heat flux generated by internal energy, and the effect of temperature on
plastic deformation is considered by the flow stress at that temperature. The unknown function of
temperature distribution is constructed using reproducing kernel approximation. Contours of the
temperature field of a metal ring under compression are obtained. Using the thermal-mechanical
coupling method, the results are compared with those obtained by FEM and experiment to verify
the accuracy of the proposed method.
Hot Forging Process Design Optimization Based on Approximate Model and FEM Simulation
Authors: Chen Xue Wen , Jung Dong Won , Sun Ai Xue
Published: March 2009

Technology and die design are very important in the development of forging products due
to its great influence on the quality, cost and manufacturing efficiency of the final products as well as
the life of the forging die. In the environment of the severe competition, how to improve the quality of
forging technology and die design, to reduce the product cost and ultimately to enhance
competitiveness of the forging factory are the problems that forging technology and die designer have
to solve. In order to improve the quality of forging technology and die design, a design optimization
method based on approximate model (response surface model) and FEM technique for hot forging
process is proposed in this paper. During design optimization process, finite element analysis is
incorporated to calculate the objective function and check the design alternatives. Design of
experiment (DOE) method is used to collect sample points and calculate the polynomial coefficients
of response surface model, and approximate model is used to calculate the optimum search direction.
Finally, a case study is conducted for a gear workpiece hot forging process. The objective function is
the degree of uniformity of equivalent-strain, which can be defined as mean square deviation of the
equivalent-strain in each element and the average equivalent-strain of all elements, and the design
parameters are the initial H0/D0 ratio of billet and the key dimensions of the die. Then the design
optimization mathematical model is established. The result shows that the objective function value is
dropped from 0.7914 and converges at 0.4843 within 17 iterations, the optimal design parameters are
obtained.
Numerical Simulation of Induction Heating Process of Continuous Casting Slab
Authors: Liu Hao , Chen Li Liang , Zhou Jian Xin
Published: March 2009

Compared with traditional blazing furnace, the Continuous Casting-Direct Rolling is an
advanced manufacturing steel technology, which can reduce energy waste, decrease pollution and
enhance efficiency. The characteristics of steels during induction heating are complex, the change
of material properties with temperature makes exact analysis methods very difficult to implement.
Therefore, a powerful computer aided numerical tool (i.e., finite difference analysis) is selected to
numerically model the induction heating process in this paper.
The mathematic model coupling with electromagnetic field and thermal field was established,
and it was solved by finite difference method (FDM), thus the slab temperature distribution and its
variation with time were obtained, and the characteristics in whole induction heating process were
studied. To validate the program feasible, the results were evaluated and compared with experiment
results, which showed that the simulation results are reliable and effective.
The skin effect in heating process from the two results was studied and demonstrated, the
temperature change caused by different parameters such as the induced power intensity and the
corner radian were also presented, which indicate that the slab temperature can be heated uniformly
through adjusting these parameters, thus the continuous casting slab can meet the rolling
requirement.
Spatial Structure Injection Molding Analysis of Suspended Bio-Carriers
Authors: Jiang Fan , Chen Wei Ping , Li Yuan Yuan
Published: March 2009

The realizability for spatial structure of suspended bio-carriers should be considered in the
process of structure designing. Injection molding analysis could obtain the injection performance of
spatial structure, and provide the references for economic benefit of structure realization and structure
optimization, so it become an important tool for structure designing and optimization. In oder to apply
the injection molding analysis to the process of bio-carriers designing, three structures, multi-plane
spherical structure, straight chip columnar structure, wing panel structure are designed. Their
injection performances, such as best location of injection, fill time, and injection pressure are be
compared, the results show that the multi-plane spherical structure has the best injection economic
benefit.
Application of Level Set Method to the Simulation of Liquid-Gas Two-Phase Flow during Mold Filling
Authors: Hao Jing , Chen Li Liang , Zhou Jian Xin
Published: March 2009

Level Set Method is an appropriate mathematical tool for solving two-phase flow
problems. The main advantage of Level Set Method is its efficiency to deal with complex
interfaces, even if topology changes. In this paper, the liquid-gas two-phase flow is simulated using
a combination of Level Set Method and SOLA method. SOLA is used to compute the
Navier-Stokes equation, and Level Set Method is used to track the interfaces between the liquid and
the gas during mold filling process.
The difficulty in the simulation of two-phase flow comes from great change of physical
parameters (e.g., density and viscosity) across the interfaces. Level Set Method allows for large
density ratio and jump in viscosity without reconstructing the numerical grid. In this work, the
forming and moving of the gas bubbles in liquid were numerically simulated by Level Set approach.
The numerical simulation results and experiments suggest that Level Set Method is quite
reliable and effective for the simulation of liquid-gas two-phase flow during mold filling.
Research of Favorable Conversion of Friction during Powder Compaction
Authors: Wang De Guang , Wu Yu Cheng , Jiao Ming Hua , Xie Ting , Yu Jian Wei
Published: March 2009

The warm powder compaction process is simulated by the finite element analysis
software which is MSC/MARC. The thermal mechanically coupled analysis method is applied
based on the updated Lagrangian Method to study the influence of different velocities ratio of die
and punch υdie/υup-punch on the properties of green under different frictional condition. The results
indicate that for cylindrical powder metallurgic products, different velocity ratios have great
influence on the distribution of relative density and equivalent stress. The frictional force can be
converted to the favorable force through adjusting the velocity ratio, and this method can obtain
higher uniform distribution of relative density and stress of green.
Investigation on the Key Technologies of Mechanical Expanding of Large Diameter LSAW Pipe
Authors: Xiao Shu Hong , Zha Chang Li
Published: March 2009

Long distance transmission pipeline is one of promising transportation methods developed
in recent years. It is safe, economical, convenient and prompt. It is mainly used in transmitting gas,
liquid, and other dispersed material. Oil and natural gas is especially suitable to be transmitted by high
pressure large diameter longitudinal submerged arc welded (LSAW) pipelines. Mechanical
expanding is one of the most important processes in the production of large diameter LSAW steel
pipe for long distance transmission pipeline. Firstly, the LSAW steel pipe mechanical expanding is
modeled. Two FEM models are established to simulate the mechanical expanding process at the cross
section and longitudinal section of the LSAW steel pipe respectively. Secondly, the deformation
characteristics of the LSAW steel pipe are simulated while mechanical expanding processes. Finally,
main mechanical expanding process parameters and their influence on the quality of finished LSAW
pipe are analyzed in detail according to the FEM simulation. The results presented by the analyses are
very consistent with the experiment, and can be used to direct the production of LSAW steel pipe.
Numerical Simulation of Basal Parameters for Fatigue Evaluation of Electromotor Rotor Welded Structure
Authors: Zhao Zhi Li , Yang Jian Guo , Liu Xue Song , Fang Hong Yuan
Published: March 2009

Fatigue strength of welded structures can be estimated by obtaining local notch stress
concentration under the service loading. On the bases of considering influence of weld geometry
details and micro-support notch effect at weld toe, the local notch stress fields of welded structure of
large-scale electromotor rotor were simulated by global-local analysis in finite element method
(FEM) to evaluate the fatigue strength. The fatigue notch factors of different weld shapes were also
determined. For longitudinal fillet weld of shaft-ribs welded structure under moment of torsion, as
well as sealing weld in axis head faces of ribs under gravity, the simulation results show that at weld
toe the fatigue notch factor of concave fillet weld is the lowest, the one of flat fillet weld is second
lowest, and the one of convex fillet weld is the highest.
Numerical Simulation of Residual Stress in the Glass-to-Metal Diffusion Seals
Authors: Xu Di , Ling Xiang
Published: March 2009

The glass-to-metal seals are widely used in the solar thermal power. When a glass-to-metal
seal is cooled in the process of diffusion welding, the residual stresses are generated due to different
thermal contraction between the two materials. The residual stresses built up along the interface near
the end of the seal can induce welded joints to crack and decrease the fatigue intensity of the welded
joints and thus are of technical importance. In order to obtain the residual stresses existed in the
diffusion welded joints, the glass-to-metal vacuum diffusion sealing process were simulated by using
finite element software ABAQUS. Furthermore, the influences of temperature, time, vacuum, and
seal pressure on the strength of the glass-to-metal diffusion welding were analyzed. The optimization
of the diffusion welding process parameter based on the simulation of the residual stress and analysis
of the micro-structure and the macro-mechanical performance of the diffusion welded seals was
carried out. The distribution of residual stress on the surface of the glass-to-metal joint caused by
welding is measured by X-ray diffraction method, and compared with the result of the numerical
simulation to prove the validation of the finite element model.