bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis and Simulation of Sensor Structure Parameters and Filling Materials Characteristics for Electrical Capacitance Tomography System
Authors: Chen De Yun , Wang Li Li , Chen Yu
Published: March 2009

The object of this paper concerns with the research of 8-electrode oil-water two-phase flow
electrical capacitance tomography system. The distribution models of sensor’s field are established by
the finite element method for the influence of the parameters of sensor’s structure on the performance
of sensor. The analyses of simulation and experiment and the sensor’s optimization design are done,
and the measure function of sensor’s optimization design is proposed based on sensor parameters that
are listed as follows: length of electrodes, stretch angle of electrodes, thickness of pipeline,
permittivity, thickness of stuff filled between screen and electrodes, radial electrodes and so on. In
conclusion, the final parameters and materials adopted are proved better than those adopted before.
Consequently the sensitivity and uniformity of the sensitive field is improved and the design of the
measurement circuit is easier, and the data precision of sensitive field is enough for image
reconstruction.
Dynamic Characteristic Analysis of the Micropump Considering the Diaphragm Stiffness
Authors: Jiang Dan , Li Song Jing , Bao Gang
Published: March 2009

Being as a functional material, piezoelectric ceramics is applied to drive a micropump
when it is composed to be a thin membrane on a brass film to form a diaphragm. According to the
properties of the piezoelectric material, the stiffness of the diaphragm influences the vibration
displacement and therefore the supply flow rate of the micropump. This paper focuses on the
dynamic characteristic study of the micropump and the stiffness influence of the diaphragm on the
characteristics. The mathematical model of the valve-less micropump considering the diaphragm
stiffness is developed in order to predict the dynamic characteristics of the piezoelectric valve-less
micropump. Using the 3-D finite element analysis (FEA) method, the static and vibration mode of
the diaphragm are analyzed to obtain the diaphragm stiffness and natural frequency. The method
using Matlab is to predict the pressure and flow rate characteristics of the micropump when the
diaphragm stiffness is considered or not. Comparison of the simulation results shows the stiffness of
the diaphragm influences the dynamic characteristics of micropumps. It also shows that the method
combining FEA software with Matlab provides a possible and effective tool to take the diaphragm
stiffness into account when the pressure and flow rate characteristics of micropumps are studied.
Modelling Fabric’s Optical Behaviors
Authors: Yang Hong Ying , Zhu Su Kang , Li Ke Jing , Pan Ning
Published: March 2009

In this paper, existing models of fabric’s optical behaviors are classified and estimated
briefly. Then, basing on the optical theories, this paper abstracts the commonness of fabric’s optical
behaviors and put forward an improved model of them, which includes a physical model and its
corresponding mathematical model. The physical model describes the light falling on fabrics splits
into six components, which compose another four components. The ten light components divided by
the incident light yields ten light component parameters, which are functions of the wavelength. The
mathematical model connects the ten light component parameters and gives formulas to calculate
them. Thus, the light component parameters are connected with the basic optical parameters and
structural parameters of fabric. This improved model provides a fundamental and theoretical guide for
studying fabric’s optical properties systematically, which has been proved to be effective in solving
some problems related fabric optical properties.
Study on Method of the Multi Control Task and Synchronized Data Acquisition of the Themo-mechanical Simulator
Authors: Su Hai Long , Luo Zong An , Wei Jin , Zhang Dian Hua , Wang Li Jun
Published: March 2009

In this paper, the functions and tasks’ distribution of control system in thermo-mechanical
simulator are described.The characters and methods to solve multi-closed loop tasks and
contradiction among synchronous collection are explained. This work combines technical processes.
and introduces design feature and principle of operation of control system that is made up by
different controllers.
Numerical Simulation of Temperature Distribution in Conductive Asphalt Solar Collector due to Pavement Material Parameters
Authors: Wu Shao Peng , Li Bo , Wang Hong , Qiu Jian
Published: March 2009

Asphalt pavement serving as solar collector has been developed for the heating and cooling
of adjacent buildings as well as to keep the pavement ice-free directly. Material parameters such as
thermal conductivity and heat capacity are some of the critical parameters related to the efficiency of
the asphalt collector. Graphite powders were utilized as thermal conductive fillers to make asphalt
collector conductive so as to improve the efficiency of the asphalt collector. The material parameters
change with the addition of graphite consequently. In order to access the solar energy absorbability of
conductive asphalt collector, it is necessary to predict the temperature distribution within the asphalt
layers. A transient, two-dimensional finite element model is developed to predict temperature
distributions in conductive asphalt solar collector due to material parameters. The ability of accurately
predict asphalt pavement temperature at different depths will greatly help pavement engineers in
determining the solar energy potential of conductive asphalt collector. The results from the prediction
model show that the surface temperature of pavement decreases slightly with addition of graphite.
The differential maximum asphalt temperature variation at a depth of 10cm is significantly more than
that at the surface. Higher temperature and lower temperature gradient can also be observed at the
depth of 10cm because the heat conduction is accelerated by the addition of graphite.
Microstructure Simulation of Die Casting Magnesium Alloy
Authors: Fu Zhen Nan , Xiong Shou Mei
Published: March 2009

A cellular automaton (CA) based model for two-dimensional simulation of the grain
morphology of high pressure die casting magnesium alloy was developed. The heterogeneous
nucleation, the solute redistribution both in liquid and solid, the interface curvature and the growth
anisotropy during solidification were also considered in the model. By fitting the curve of grain
density distribution, parameters of continuous nucleation equation based on Gaussian distribution
were calculated. The microstructure simulation of step-shape die castings of AM50 magnesium
alloy was studied. The metallographic microstructure of the castings at the surface and center of
three steps with different initial die temperature was investigated. The simulation results were
compared with the experimental results and they were in good agreement on average grain size.
Investigation of Forming Conditions on Microstructure Development and Mechanical Stability of Trip Steel
Authors: Zrník Jozef , Murnsky O. , Horňak Peter , Fujda Martin
Published: March 2009

Experimental simulations of thermomechanical processing (TM) using press forging of
Si-Mn TRIP (transformation induced plasticity) steel were performed. In order to rationalize the
retained austenite (RA) volume fraction, six TM schedules were employed at experiment where
different austenite conditioning was considered. The various multiphase structure characteristics
were obtained after of TM processing, with different volume fraction of ferrite, bainite and RA. The
modification of structural characteristics influenced the mechanical properties of TRIP steel. The
present work also focuses on monitoring of RA transformation during mechanical incremental
straining using in situ neutron diffraction technique. This method is used to characterize the kinetics
of RA transformation and its stability during the straining.
Diffusion Interaction between Two Metals, One of Which is in Liquid State
Authors: Savitskii Arnold P.
Published: March 2009

Processes of diffusion interaction between solid and liquid phases take place in such
phenomena as wetting, spreading, dissolution, contact melting, liquid metal corrosion, changes of
mechanical properties of metals and alloys being in contact with melts, etc. The knowledge of the
mechanism and regularities of this interaction is necessary for development of such technologies, as
sintering, self-propagating high temperature synthesis, impregnation, casting, welding, soldering,
liquid metal cladding, etc. However, in despite of the fact that the problem of diffusion interaction
between solid and liquid metals is of the paramount importance as for science as well for practice,
no intelligible theory of the phenomenon is available. The paper fills the gap in our knowledge of
this subject.
The Study of Thermal Boundary Condition for CFRP Pressure Vessel with Metallic Liner during Manufacture Process
Authors: Hu Zhao Hui , Wang Rong Guo , Ma Li , Du Shan Yi
Published: March 2009

The heat convection was considered the main heat exchange type in the autoclave where
CFRP pressure vessel was cured in this analysis. To determine the heat convection coefficient, it
needed the combination of theoretical calculation and temperature test. In the theoretical
calculation, the determination of the heat convection coefficient was considered as an inversion
problem of thermal conduction. By adjusting convection coefficient value in the finite element
calculation, optimization method was employed to obtain a good agreement between calculated
temperature and measured temperature. In the temperature test, the metallic liner of CFRP pressure
vessel was used as test component to record temperature data which was compared with the
calculated temperature. The calculated results reveal that the maximum value in convection
coefficient sequence is 19.87 W/m2/K; the minimum value is 0.16 W/m2/K; the maximum
temperature deviation between calculation and test is 1.67 °C. The results present the equivalent
thermal boundary condition for the simulation of curing process of CFRP pressure vessel.
Numerical Simulation and Experimental Method for Auto-Panel Forming Defects Analysis
Authors: Xiang Hui Yu , Leng Chong Jie , Zhong Yue Xian
Published: March 2009

This paper investigated the forming defects causation and related resolving measures by
combining numerical method with experimental technique. A practical case of one auto-body panel
stamped parts with forming defects was studied in detail. A new approach determining the
causation of forming defects and finding out resolving ways was proposed. Firstly, uses numerical
method to analyze the characteristics of the whole forming process by dividing the forming process
into virtual steps, so as to obtain the forming feature such as stress & strain distribution during the
stamping process. Secondly, uses experimental grid method to measure the real plastic strain
distribution of the defective area thus to analyze the forming rule of this area. By synthesizing both
methods and carrying out extensive analysis, it is possible to make sure the cause of the defects and
put out solving scheme further. The study shows that numerical combined with experimental
method is an effective way in analyzing and resolving forming defects for auto-body parts.
A Research on Steel Synchronizer Gear Ring's Precision Forging
Authors: Xue Song , Zhou Jie
Published: March 2009

Precision forging is an important manufacturing procedure of steel synchronizer gear ring
forming. FEM software DEFORM_3D was applied to simulate the forming process and the problems
in the forming process were been solved. The important factors those influence on precision forming
of steel synchronizer gear ring are studied and the results are verified in practice. The results show that
the size of billet, forging temperature, and thickness of web strongly influence the forming quality of
steel synchronizer gear ring.
Macrokinetics Hierarchies of States at Dynamic Superplasticity
Authors: Kitaeva Daria Anatolievna , Rudaev Yakov Isaakovich
Published: March 2009

Dynamic superplasticity of aluminium alloys is considered from positions of the theory
of nonequilibrium phase transitions. Evolution of the open nonequilibrium system by which
temperature-rates process in materials is modelled, is investigated within the framework of worked
out defining relations with attraction of thermodynamic functions of the response. It is shown, that
to peak of superplasticity there corresponds a maximum of a specific thermal capacity. The entropy
production in optimum thermomechanical conditions of superplasticity aspires to a minimum which
corresponds to formation of qualitative ultrafine-grained structure. With use of the Focker-Plank
equation mechanisms of deformation characteristic for superplasticity and boundary conditions are
analyzed. It is shown, that at superplasticity the main is the mechanism grain-boundary sliding, and
in metastable conditions are added diffusionary processes. Influence of the specified processes in
conditions of superplasticity becomes prevailing.
Temperature Prediction of Seven-Pass Finishing Rolling of Hot Thin Strips by FEM
Authors: Qu Zhou De , Zhang Qun , Zhang Shi Hong , Lei Chen
Published: March 2009

Temperature evolution is one of the important parameters of mechanical properties of
thin strip products. So the ability of prediction of temperature history before processing is critical to
the processing scheme of controlling rolling and controlling cooling. In this paper an integrate
model of finite element method is presented for the prediction of the temperature evolution in the
finishing rolling during hot strips. The model takes into account the interaction between thermal
behavior and mechanical behaviors. By using the second-development method based on the
commercial code thermal behavior and temperature distribution of strips through seven-pass
finishing rolling are described in detail. A method for computing the mean temperature at the exit of
each pass is approached. Using this method the mean temperature can be attained after each pass. In
one seven-pass thin strip rolling mills the temperature at the exit after each pass is measured by the
pyrometer. The measured results and the simulation results are compared. The validity of the
proposed analysis model is examined. The computing results are in agreement with the measured
results.
Simulation of the FGH96 Superalloy Microstructural Changes under Different Deformation Conditions
Authors: Wang Xiao Na , Li Fu Guo , Liu Yu Hong
Published: March 2009

This paper studies FGH96 P/M Superalloy dynamic recrystallization phenomenon under
isothermal forging conditions. Curves of work hardening rate θ versus flow stress σ and RTT
curve of dynamic recrystallization are gained through the analysis. At the same time, some
parameters are confirmed including peak strain, critical strain and the maximal softening strain. On
the basis of the analysis, the type of FGH96 P/M Superalloy dynamic recrystallization is exactly
estimated. The quantitative metallography method is adopted to determine the recrystallized grain
size. With combining the obtained data and parameters, FGH96 P/M Superalloy dynamic
recrystallization mathematic model is established by regression method. At the same time, the forging
process of FGH96 P/M superalloy is simulated by using software MSC/Superform under different
deformation conditions such as deformation temperature and deformation velocity. The contour
images of the grain size distribution under different conditions and different deformation degree are
gained and analyzed. With the analysis, it is known that the effect of the different deformation
conditions on the microstructure of the forging is obvious and there is different distribution of the
grain size on various locations, which indicates that the deformation degree of the billet also has
influence on the grain size.
Numerical Simulation Analysis on Cold Closed-Die Forging of Differential Satellite Gear in Car
Authors: Zhang Yao Zong , Huang Jian Bo , Lin Xue , Fang Quan Shui
Published: March 2009

The cold closed-die forging process of the gear is a kind of new technique of the
precise forming of gear in recent years. In this paper, the cold closed-die forging process of
differential satellite gear in car was analyzed through numerical simulation method. Forming mold
was designed with Pro/E Wildfire2.0 which included four components : upper punch, lower punch,
tooth shape upper die and lower die for Normal Cone. The three-dimensional models of satellite
bevel gear mould were built and imported into numerical simulation software DEFORM-3D.
Because the gear has the uniform circumferential features, in order to save time and improve the
accuracy, only one tooth was simulated, and the full simulation outcome of 10 teeth was mirrored
from this one. Through the numerical simulation analysis of DEFORM-3D, the instantaneous
deformation and stress filed were gained. Forming defects were forecasted and the cold closed-die
forging rule for satellite gear used in car was obtained which can provide effective references for
no-flash cold forging process of planet bevel gear and the mold design.
The Establishment of Mathematics Model of Velocity Field in Strip Cast-Rolling Deforment Area
Authors: Sun Bin Yu , Yuan Shi Jian
Published: March 2009

According to the N-S equation in fluid mechanics, it is analyzed the rheological
properties of strip cast-rolling deforment area with flow function method. The research problem can
be simplified into 2-D when the wide of cast-rolling strip are greater than thickness. But, it still
difficult to find solution for established two-dimensional partial differential equation directly. A
mathematics model of velocity field in the cast-rolling area has been built by flow function method.
The model not only satisfies the continues equation, the condition of no-compression and velocity
boundary, but it also make the most possible to solute partial differential equation. So, in the future
continue research, it has created possible conditions for saluting the mathematics model of average
unit compression stress distribution in the cast-rolling deforment area.
Prediction of Rolling Force during Temper Rolling
Authors: Larkiola Jari , Nylander Jari , Kähkönen V. , Judin M.
Published: March 2009

In temper rolling thickness reduction is small (0,5 – 2%) and the elastic deformation of
the work roll should be taken into account. During finishing rolling, classical cold rolling theories
fail to predict the roll flattening and thus the rolling force. Numerous different mathematical models
have been developed for temper rolling process. However, often the non-circular theories are
computationally expensive and the range of usability is questionable. In this study, elasto- plastic
finite element analysis, laboratory rolling tests and inverse computing from skin pass mill process
data has been carried out. The aim is to find the roll shape, contact length and the rolling force to
create a simplified model for controlling of temper rolling. In addition, the ability of different skin
pass rolling theories has been compared with measured process values.
Research on Simulating of Controlled Rolling and Controlled Cooling Process for Mo Micro-Alloy Steel
Authors: Li Gui Yan , Zhao Bao Chun , Pang Zao Fu , Liu Yong Hao , Ma Hui Xia
Published: March 2009

The transformation production and recrystallization for Mo Micro-alloy Steel had been
carried out on the Gleeble-3800 thermo-mechanical simulator. Based on the schedule, TMCP was
applied to two stages multi-pass hot rolling experiments and the influences of the technological
parameters on microstructure and mechanical property were analyzed. The results showed that the
microstructure, precipitation and mechanical property of Mo Micro-alloy steel were strongly
affected by the start-rolling temperature, the end-rolling temperature, the cooling rate and the
relaxation time. The appropriate parameters were used and the ideal volume fraction of the acicular
ferrite was observed by using metallographic microscope and transmission electron
microscope(TEM).
Density Functional Theory Applying in the Computation to the Properties of Copper Surface
Authors: Cheng Hong Tao , Yang Jian Guo , Fang Hong Yuan
Published: March 2009

The properties of different Cu surface were studied by the pseudo-potentials method based
on density function theory. The lattice constant obtained with GGA(Generalized Gradient
Approximation) is close to the experimental values than that with LDA(Local Density
Approximation), so we adopt the GGA to simulate the cohesive energies and the surface energies of
the Cu(100), Cu(110) and Cu(111) surface. The simulated results are shown to be in agreement with
the macroscopic validity of the experimental measurements.
Study on Temperature Distribution of Plasma Surface Alloying Furnace
Authors: Li Zhong Hou , Liu Sha Sha , Cheng Zhi Yong
Published: March 2009

The objective of this research was to develop methods for improved the uniformity of
temperature distribution within plasma surface alloying furnace by simulating the heat transfer
process and numerical calculation. Results show that the structure of charging basket, hanging
auxiliary cathode plates in both sides of charging basket and blackness of material influence
strongly temperature distribution within the plasma surface alloying furnace. Discharge intensity of
the center zone can be weakened through increasing the distance between backs both column blades
in center of the furnace, which decreased the consumption of discharge power in center, depressed
temperature of the center zone of the furnace. Intensity of discharge in fringe of the charging basket
can be reinforced and that of discharge in center can be weakened when auxiliary cathode plates
were hanged to outer flank of the charging basket, which increased boundary temperature of the
system, at the same time the auxiliary cathode plate plays a heat preservation role. Decreasing the
blackness of outside material of charging basket may decrease heat dissipating capacity of outside,
decrease temperature difference of outside and center of the furnace and improve the uniform of
temperature distribution in the furnace.
Reliability Calculation of Welded Pressure Pipe with Circumferential Crack Based on 3-D Elastic-Plastic SFEM
Authors: He Bo Lin , Yu Ying Xia , Huo Li Xing , Zhang Yu Feng
Published: March 2009

In this paper, the reliability of welded pressure pipe with circumferential surface crack was
calculated by using three dimensional stochastic finite element method. This method has overcome
the shortcomings of conservative results in safety assessment with deterministic fracture mechanics
method. The calculation of reliability was based on three dimensional elastic-plastic stochastic finite
element program which was developed by ourselves. The effects of variables such as fracture
toughness, bending moment and the depth of the circumferential surface crack on the structure
reliability were also discussed. The calculation results indicate that the crack depth has great effect on
the reliability of the welded pipe. When the mean value of the crack depth is changed from 3mm to
7mm, the failure probability of the welded pipe will change from 10-8 to 10-2. The bending moment
also has great effect on the reliability of the welded pipe. When the mean value of moment is changed
from10000 N.m to 15000 N.m, the failure probability of the welded pipe increases dramatically for
the same circumferential crack depth. Irrespective of the changing of moment, the pipe has higher
reliability if the crack depth is less than 5mm(a/t<0.5, t is the thickness of the pipe). The method has
put forward a new way for safety assessment of welded pipe with circumferential surface crack.
Numerical Simulation of Temperature Field and Stress Field of Electron Beam Brazing Stainless Steel Radiator
Authors: Li Jun Min , Chen Fu Rong
Published: March 2009

Aiming at the radiator with tube-to-plate structure applied usually in aeroplane, a
two-dimensional model for finite element analysis was established in this work. By ANSYS software,
the temperature field and stress field of electron beam brazing (EBB) 1Cr18Ni9Ti stainless steel
radiator by two kinds of process were numerically simulated. The calculated results of temperature
field show, by the stage-by-stage heating process, the uniform temperature distribution of radiator
faying face was obtained. The temperature of most regions is between 1042~1051°C, which is in the
range of brazing temperature. The calculation results of stress field indicate, for radial residual stress,
the obvious stress concentration region was found in faying face by direct-heating process; while
there was no stress concentration in faying face by stage-by-stage heating process. For circumferential
residual stress, compared the stage-by-stage heating process with direct-heating process, the peak
value of tensile stress reduces by 11.2%. Compared circumferential residual stress with radial residual
stress by two kinds of brazing process, the peak value of circumferential tensile stress is higher than
radial tensile stress. So the dangerous position of faying face is along circle direction, namely, the
heating direction of scanning electron beam. Consequently, the temperature difference between
different positions in faying face must be controlled well during heating. The reduction of temperature
difference can fall the peak value of tensile stress and improve the distribution of residual stress.
Investigation of the Influence of Shot Peening on Stress Corrosion Cracking of Stainless Steel Welded Joints
Authors: Ling Xiang , Ni Hong Fang , Ma Gang
Published: March 2009

High residual tensile stress is an important factor contributing to stress corrosion cracking
(SCC). Shot peening can impose compressive stresses on the surface of welded joints that negate
the tensile stresses to enhance the SCC resistance of welded joints. In the present work, the
distribution of residual stress caused by welding is measured by X-ray diffraction method. The
maximum stress in the weld is close to the yield strength of AISI 304 stainless steel, and the stresses
are negative at both ends of the weld and far from the weld. The X-ray method is also used to
measure stress caused by shot-peening. The results show that the higher the peening coverage, the
higher the residual compressive stresses in the surface of weldments. While under the same
condition, the residual compressive stresses induced by glass beads shot-peening are larger than
those by cast steel shots. Temperature and stress fields of welding are simulated by using ABAQUS
codes. The 3-D solid elements are used in FEM. Temperature depending on material properties as
well as the convection and radiation as boundary conditions are considered. The 3-D linear
reduced-integration elements are used to simulate the shot peening process. The results of
simulation have a good agreement with experimental data. All unpeened and peened weldments are
immersed in boiling 42% magnesium chloride solution during SCC test. Unpeened specimens crack
after immersion for 6 hours. The steel-peened specimens with 50% coverage crack after 310 hours,
while the steel-peened specimens with 100% coverage crack for 3500 hours. However, steel-peened
specimens with 200% coverage and glass-peened specimens with 50%, 100% and 200% coverage
are tested for a total of 3500 hours without visible stress corrosion cracks in the peened surfaces.
The experiment results indicate that shot peening is an effective method for protecting weldments
against SCC and weldments peened by glass beads resist SCC better than those peened by steel
shots.
Numerical Simulation of Laser Surface Micro-Texturing
Authors: Liu Hui Xia , Chen Yi Xing , Wang Xiao , Meng Xiao Xia , Fu Yong Hong , Cai Lan
Published: March 2009

In order to predict the geometry character of laser surface micro-texturing, the finite
element analyzing software ANSYS is used to simulate temperature field and crater on the laser
ablation. The influence and change regulation of laser intensity, laser pulse number and pulse
duration in laser surface texturing are analyzed in detail. The simulation results conclude the best
laser intensity in laser-pulse and materials interactions on certain conditions, and the best pulse
duration in nanosecond laser micromachining. This research establishes the foundation for laser
machining regular non-smooth surface in a rapid and effective way.
Analysis and Evaluation for Usability of the Low Hydrogen Type Structural Steel Covered Electrode
Authors: Wang Yong , Wang Bao , Gao Jun Hua
Published: March 2009

Metal transfer mode of the low hydrogen type structural steel covered electrode is the
one that coexists as the globular short-circuiting transfer and the fine droplet transfer in the
flux-bridge. Component of the metal transfer modes has a direct effect on usability of the covered
electrode. The oscillograms of the arc voltage and the welding current gained using the traditional
photoelectric oscillograph can only qualitatively describe the general characteristics of metal
transfer, but can’t make a quantitative analysis. Using the ANALYSATOR HANNOVER, the
welding electrical parameters are measured and analyzed. Four characteristic information values
correlated with usability of the covered electrode, such as the frequency of the globular
short-circuiting transfer, the globular short-circuiting time, the mean value of the globular
short-circuiting time and the mean value of the weighted arcing time, are extracted. The method
of principal component analysis is applied to determining the evaluation index for usability of the
covered electrode. Thereby quantitative evaluation for usability of the covered electrode is
realized. A new method is offered for scientifically evaluating usability of the low hydrogen type
structural steel covered electrode.
Numerical Simulation of Welding Residual Stress and Post-Weld Heat Treatment for Dissimilar Steel Welded Joint
Authors: Zhang Guo Dong , Zhou Chang Yu
Published: March 2009

By the finite element analysis software ABAQUS and the function of coupling process
between heat and stress, the welding residual stress of Cr5Mo and 20 steel joint was analyzed. In
addition the heat treatment of dissimilar steel welded joint was simulated. The residual stress
distributions of dissimilar steel welding and heat treatment after welding were obtained. The
comparison of welding residual stress between the homogenous steel and dissimilar steel was
carried out. The results indicate that the welding residual stress of the same steel is lower than that
of dissimilar steel welded joint obviously. Because of the difference of thermal expansion
coefficient for base metal and welding microstructure, the relatively higher residual stress is
produced due to the bigger thermal expansion coefficient of base metal. The highest annular
residual stress is in welding line root of internal wall, while the highest axial residual stress is in
welding line surface of outer wall. The welding residual stress of dissimilar welded joint is reduced
obviously after heat treatment. The research results provide the possibility for optimizing the
welding procedure and improving the reliability of dissimilar steel welding joint.
Numerical Modeling of High Power MAG Welding on the Plate
Authors: Huang Jian , Bach Friedrich Wilhelm , Windelberg D.
Published: March 2009

In the case of welding of T-joints in a special structure, the joining is realized through a
total penetration of deck plates. For the deck plate’s thickness over 6 mm, high power MAG welding
process should be applied. To help experimental optimizing of this welding technology, a 3D
quasi-stationary numerical model was established to predict the penetration and weld form of the high
power MAG welding on a thick plate. In the analysis a new volumetric heat source model was put
forward which considers the heat directly from the arc und that from transferred droplets separately.
Because the weld pool surface under the arc was strongly pressed, the droplet heat source in the model
was located under the workpiece surface. The size of the droplet heat source model was determined
on the base of physical principles and available experimental data. Using a commercial finite element
software the weld form inclusive penetration under different welding parameters was then simulated.
Through comparison with the experimental results the presented FE-model was verified.
A Study of the Environment–Friendly Chrome-Free Chemical Conversion Coating on 2024 Aluminium Alloy
Authors: Chen Dong Chu , Gong Wen Hui , Huang Zhu Zhou , Li Wen Fang
Published: March 2009

In order to develop an environment-friendly method of forming a chemical conversion
coating on 2024 aluminium alloy surface without the toxic hexavalent chromium compounds, in
this paper a process with sodium molybdate and potassium permanganate as the main compositions
of the treating bath has been investigated. Solution composition and process parameters have been
optimized. The chemical conversion coating has good corrosion resistance, evaluated with dropping
test. Micro-structure and components of the conversion coating have been studied by various
micro-analysis methods, and the growth mechanism of the chemical conversion coating has also
been investigated.
Numerical Simulation of Interfacial Bonding Degradation of Composites under Two-Stage Loading
Authors: Chen Yan Hua , Zhu Qing Jie
Published: March 2009

Bonding degradation at interface is one of main damage forms of composites, especially
under fatigue loading. Interfacial bonding degradation of FRC under two-stage tension loading is
studied, which is base for variable-amplitude cyclic loading existing widely in actual engineering.
Based on the shear-lag model and considered the asymmetry of interfacial damage, the mechanical
governing equations of fiber and matrix are established and related solutions are obtained firstly.
Two kinds of loading models are chosen, one is low-high alternate loading, and the other is low
early and high late loading. By the aid of the Paris law and the energy release theory, a relationship
between debond rate and cycle number is established. Then the interfacial debonding is simulated
under the two-stage tension loading. The rules of the crack growth are analyzed for low-high
two-stage loadings. It is found that stress amplitude has great influence on interfacial debonding
under two-stage loading. Low stress amplitude in a certain range can postpone interfacial bonding
degradation. And interfacial damage extent is greater than that under constant-amplitude fatigue
loading. Present study is helpful for analyzing the fatigue damage of engineering materials and
structures.
Structure Optimization in the Stacked Package of IC Microstructures
Authors: Li Hong Peng , He Yu Ting , Zhang Heng Xi , Cui Rong Hong
Published: March 2009

This paper presents our effort to reduce thermo-mechanical failures related IC packaging
reliability problems. These reliability problems are driven by the mismatch between the different
material properties. First of all, finite element analysis are adopted to investigate the influence of
encapsulation structures and material properties on the stress distribution in dielectric layers and
plastic strain distribution in die for a typical stacked package of IC microstructures. Results show
that thinner package body, lower thermal stress and smaller plastic strain can be realized in this
micro-structure with the different design geometry parameters and materials properties. Secondly, it
was also found that the transition layer of TiN between the die and dielectric layer has a pronounced
influence on decreasing the local stress in the passivation layer by comparison analysis. These
studies would be beneficial to improve the reliability of stacked IC micro-structure packages.
Effects of Thermal Treatment on the Morphology and Properties of CSM/Poly(Urethane-Isocyanurate) Composites Formed by SRIM Process
Authors: Tang Hong Yan , Wang Ji Hui , Gao Guo Qiang , Chen Wen Xing
Published: March 2009

Fiberglass continuous strand mat(CSM)/poly(urethane-isocyanurate) composites were
formed by SRIM process, treated under different conditions and then characterized based on
dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), scanning
electron microscopy (SEM) ,transmission electron microscopy (TEM) and the mechanical property
tests. The results show that the mechanical properties of the composites could be increased with
improving the degree of microphase separation. At a given temperature (120°C), the degree of
microphase separation is the highest for 4h and decreases gradually with prolonging treatment time.
For a given time (4h), the well microphase-separated morphology is obtained and the degree of
microphase mixing is increased at 120°C and 140°C treatments, respectively. The degree of
microphase separation of the composites decreases with enhancing the temperature to 140°C.
Mechanical Approach for Prediction of Microcracking in Multipass Weld Metal of Ni-Base Alloy 690
Authors: Saida Kazuyoshi , Sakamoto Masashi , Nishimoto Kazutoshi
Published: March 2009

The occurrence of microcracks, especially ductility-dip crack in multipass weld
metal during GTAW and laser overlay welding processes of Ni-base alloy 690 was predicted by
the mechanical approach. The stress/strain analysis in multipass welds was conducted using
the thermo elasto-plastic finite element method. The brittle temperature range for ductility-dip
cracking (DTR) of the reheated weld metal was determined by the Varestraint test. Plastic strain
in the weld metal accumulated with applying the weld thermal cycle in multipass welding. The
plastic strain-temperature curve in the La free weld metal did not cross the DTR in the cooling
stage of GTAW process, however, it crossed the DTR in the cooling stage of reheating process by
subsequent welding. On the other hand, the plastic strain-temperature curves of any weld passes in
the La added weld metal did not cross the DTR. Ductility-dip cracks occurred in the La free weld
metal except for the final layer, however, any ductility-dip cracks did not occur in the La added weld
metal during multipass welding. It could be understood that ductility-dip crack would occur during
not only single-pass welding but also multipass welding when plastic strain intersected the DTR.
Effect of Weld Metal Microstructure on Cold Crack Susceptibility of High Strength Weld
Authors: Kim Hee Jin , Seo Jun Seok , Kim Jae Hak , Kim Ka Hee , Koh Jin Hyun , Ryoo Hoi Soo , Huh Moo Young
Published: March 2009

Facing the practical difficulties in reducing the diffusible hydrogen content of fluxcontaining
welding consumables like flux-cored arc welding (FCAW) wires, the present study
investigated the microstructural aspect to improve the hydrogen-induced cold crack (HICC)
resistance of multipass weld metal of 600MPa strength. Two FCA welding wires were prepared by
controlling the Ni content to give different weld microstructure, but to have similar levels of
hardness and diffusible hydrogen content. HICC susceptibility of those two consumables was
evaluated by 'G-BOP test' and also by 'multi-pass weld metal cold cracking test'. As a result of this
study, it was demonstrated that microstructural modification with decreased proportion of grain
boundary ferrite (GF) improved cold crack resistance of weld metal. The detrimental effect of GF
against HICC has also been addressed based on the characteristics of weld metal cold cracking.
Effect of Micro Structure in Fuel Cell Electrode on Concentration of Species in Reaction Layer
Authors: Sugimura Masahiko , Yasuda Kiyokazu , Matsushima Michiya , Fujimoto Kozo
Published: March 2009

Fuel cell is one of the promising candidates for mobile power source. In the fuel cell, the
design considering micro structure is considered to be indispensable for developing a highperformance
cell. In this work, the effect of the anode electrode structural design of the DMFC
(direct methanol fuel cell) on the cell performance was investigated by three-dimensional numerical
simulation. The influence of diffusion layer thickness in the electrode on the mass fraction of
methanol and carbon dioxide in the reaction layer is examined for various operation conditions. As
a result, we clarified that the micro structure change in the electrode significantly affected the mass
fraction of the species in reaction layer in the fuel cell.
Fracture Study of Ultrasonic Aluminum Wire Wedge Bonding on Copper Substrate with Mechanical Peeling-Off Method
Authors: Bang Hee Seon , Ji Hong Jun , Li Ming Yu , Wang Chun Qing , Bang Han Sur
Published: March 2009

In this paper, the characteristics of bond interface and bonding mechanism were
investigated with peeling-off method. The fracture was observed and interfacial composition was
certified by map scanning of EDX (Energy dispersive X-ray analysis). Based on the features of
interfacial characters, the actual joining area mainly distributed at bond periphery; non-bonded at
bond center. When the bonding time was lower, the ratio of the bond length to its width was larger
and elemental aluminum distributed discontinuously on the bond fracture, primarily at the
periphery. After aging, the fractures were also analyzed and Cu2Al3 intermetallic compound (IMC)
was identified. The phenomena of bond interfacial tracings were analyzed, and the bonding
mechanism was ascribed to plastic flow analyzed by finite element method based on the contact
issues.
Analysis of Solder Fatigue in Electronic Packaging Using a Mesh-Insensitive Structural Stress Method
Authors: Hong Jeong K. , Dong Ping Sha
Published: March 2009

Solder fatigue is one of the major product reliability concerns in electric packaging
design. In this paper, the application of a mesh-insensitive structural stress method, previously
developed by the authors, is demonstrated for characterizing fatigue of solder joints under thermal
fatigue and mechanical fatigue conditions. Three sets of experimental data from literature are
analyzed to demonstrate the effectiveness of the structural stress method in its ability to correlate
test data over different packaging designs, test methods, etc. As evidenced in this study, the meshinsensitive
structural stress method offers a simple but effective means to correlate the fatigue
behavior of solder joints among various test conditions. The results show that the structural stress
method can be used as an effective alternative to existing methods in the literature, in reliability
design of electronic packaging.
Numerical Analysis on the Temperature Field in Laser-Plasma Hybrid Welding of an Aluminum Alloy
Authors: Li Zhi Ning , Chang Bao Hua , Du Dong , Zhang Hua
Published: March 2009

A three dimensional heat transfer model on laser-plasma hybrid welding has been
proposed, that takes into account the interaction between laser beam and plasma arc. Through FEM
computation, the temperature fields were computed and analyzed for an Al-Li alloy during laserplasma
hybrid welding with different distances between the two heat sources. The simulation results
are in agreement with the experimental results.
Experimental and Numerical Investigations of Residual Stress Distributions in the TIG Welding Process
Authors: Miresmaeili R. , Mousavi Seiyed Ali Asghar Akbari
Published: March 2009

Residual stresses are produced in weldments due to mismatching and non-uniform
distributions of plastic and thermal strains. Attempts were made to analyze the residual stresses
distributions produced in the TIG welding process using 2d and 3d finite element analyses. No
attempts were made to find the optimum shape of grooves and gas flow rate to minimize the tensile
residual stresses in the weldments, yet. In this paper, the effects of geometry configurations and
inert gas flow rate on the residual stress distributions are presented using the thermo-elastoplastic
constitutive equations and compared with the x-ray diffraction method. In this study, convection
due to both air and inert gas flow rate along with conduction and radiation are considered.
Effect of Probe Thread on Friction Spot Joint Strength of AZ31 Mg Alloy
Authors: Nakata Kazuhiro , Ikegami Hirohisa , Tsumura Takuya
Published: March 2009

Lap joint of AZ31 Mg alloy extruded sheet can be successfully made by friction spot
joining (FSJ) process. Joint strength was strongly affected by the probe thread, which increased the
plastically deformed zone around a rotating probe and increased the tensile shear strength of the
joint in comparison with the joint made by a thread-less probe.
Short Circuit Severity Model for Pulse Gas Metal Arc Welding of Aluminum
Authors: Praveen P. , Prasad K.D.V. Yarlagadda , Kang M.J. , Rhee Se Hun
Published: March 2009

Wide use of robotic machines for welding has necessitated the development of
optimization techniques to achieve complete automation. The objective of the present study is to
develop multiple regression model for quantitatively estimating the severity of the short circuit in
pulse gas metal arc welding (GMAW-P) of aluminum, based on experimental results. The model
results were found to be in good agreement with the experimental data and yielded satisfactory
results.
UV Laser Bonding of Optical Devices on Polymers
Authors: Kim Joo Han , Kim Hyang Tae , Lee Chul Ku
Published: March 2009

UV curing adhesives have been introduced for bonding various materials at a room
temperature. It has the advantage of putting minimum thermal load on the system; however, it is not
suitable for precision bonding of micro systems such as micro optical devices because of its high
viscosity and poor control of the UV light source. In the present work, a laser-curing bonding
process of micro optical devices with a low-viscosity UV polymer adhesive has been developed. A
focused Nd:YVO4 laser beam with a spot size of 30 µm with a laser power of 100 ~ 700 mW is
used for curing a UV adhesive locally. A thin bonding layer with a thickness of a few hundred
nanometers without any thermal effects can be obtained for precision laser bonding for optical
fibers. Experimental results are provided and the process characteristics have been discussed.
Moreover, potential applications in the field of micro optical systems are introduced as well.
Understanding of Laser and Hybrid Welding Phenomena
Authors: Katayama Seiji , Kawahito Yousuke , Mizutani Masami
Published: March 2009

This paper describes laser and hybrid welding phenomena for the production of a sound
and deep weld. The penetration of laser weld beads depended upon the power and power density at
low and high welding speeds, respectively. It was reveled that the weld fusion zone geometry was
formed by keyhole behavior and melt flows. It was also understood that the production of sound
welds without porosity was attributed to no bubble formation in TIG-YAG hybrid welding of
stainless steel and the disappearance of bubbles from the molten pool surface in YAG-MIG hybrid
welding of aluminum alloy.
Improved High Temperature Tensile Properties of Ti-6Al-4V Alloy by Plasma Sprayed Coating
Authors: Li Cui , Qi Wei , Muneharu Kutsuna
Published: March 2009

A zircon coating was applied on the surface of Ti-6Al-4V alloy by plasma spray and its
effect on the high temperature tensile properties of the alloy as well as the oxidation behavior of the
alloy were studied. Tensile tests were conducted at 850°C with different strain rates of 10-4s-1,10-3s-
1, 10-2s-1 and 10-1s-1. The results show that the elongation of the coated specimens is higher than that
of the uncoated ones, while the ultimate tensile strength of the alloy is not changed. An oxide film
had formed on the surface of uncoated Ti-6Al-4V alloy, however no such oxide film was found on
the coated alloy at the early of stage. The coating can prevent oxygen penetration into the substrate
thus prevent embrittlement of the subsurface zone. The ductility could be improved by means of the
zircon coating. The optical micrographs of the specimens show little change in microstructures of
the coated and uncoated specimens. Zircon coating has no effect on the microstructure of the
substrate alloy.