bluuebunny/crossref_metadata_2025 huggingface dataset:
Compaction Quality of Bitumen Mixtures Based on Ultrasonic Methods
Authors: Xie Tao , Qiu Yan Jun , Jiang Ze Zhong , Lan Bo
Published: March 2009

Water damage of asphalt concrete pavements has been one of the major distresses in
highway engineering. Engineering experiences and research results indicate that this damage is due to
the extortionate air voids of bitumen mixtures. Paranormal porosity of asphalt mixture is largely the
result of the poor controlling of compact degree during paving process. The quality of asphalt
pavement is subjected to the controlling methods of compacting of bitumen mixtures. Ultrasonic is an
excellent method for non-destructive testing used in various engineering fields. It is also a potentially
effective tool to be applied in the control and evaluation of the compaction quality of bitumen
mixtures. This paper presents the results of a study aimed at the applicability of ultrasonic technology
for evaluation of porosity and compaction quality of bitumen mixtures. It is shown that this
technology, which has been successfully used for many years for evaluation of Portland concrete
structures, might be used in asphalt pavement engineering to provide a simple, quick, and objective
methodology for control and evaluation of the compact quality of bitumen mixtures. The results of
laboratory testing demonstrate the potential of this technology.
Development of Signal Processing Circuit of a Magnetic Camera for the NDT of a Paramagnetic Material
Authors: Jun Jong Woo , Hwang Ji Seong , Kim Kee Joo , Ogawa Kazuhiro , Lee Jin Yi
Published: March 2009

The yoke type magnetization coil and cross type magnetizer as a magnetic source, which
induce a static magnetic field on a specimen, have been used to detect cracks on a ferromagnetic
material. However, the cracks on paramagnetic materials such as aluminum alloy and stainless steel
cannot be detected by using a static magnetic source. This paper proposes a magnetic source, which
uses the induced sheet type current, for the detection of cracks on a paramagnetic material. The sheet
type AC current can be induced by using a primary coil and core. And the copper film, which includes
a sheet type current, is positioned on the specimen. Eddy currents are induced around a crack on the
specimen because the secondary sheet type current can be induced on the specimen surface. The
signal processing electrical circuits, which measure a Hall sensor peak output with the eddy current
frequency, are developed and discussed. Also the validity of the proposed signal processing circuit is
verified by detection of slit type cracks and a fatigue crack, which are introduced on aluminum alloy.
Understanding and Detecting Early Stages of SCC Initiation in Sensitized Stainless Steel by Means of Electrochemical Potential Transients
Authors: Bidhar S.K. , Watanabe Yutaka , Tsukui H. , Uchimoto Tetsuya
Published: March 2009

Series of slow strain rate tests (SSRT) were conducted on moderately sensitized
austenitic stainless steel in diluted aqueous solution of sodium thiosulfate at ambient temperature
and pressure. Only a small area of the test piece was exposed to test solution and electrochemical
potential transients obtained during the straining was used to detect an initiation or a precursor
event of stress corrosion crack (SCC). Tests were stopped intermittently after getting potential
transients, so as not to allow crack to propagate and to observe the morphology of very initial stage
of SCC initiation site. Visual observation by scanning electron microscope (SEM) before and after
the test shows direct correlation between electrochemical transient of certain characteristic to the
crack initiation. SEM observation shows δ- ferrite in the alloy as one of the preferential SCC
initiation site for typical electrochemical transient. Attempt was made to calculate the charge
associated with crack initiation event from potential transient using dummy anode test.
Study on Fault Detection and Diagnosis of the Edge-Transmission Ball Mill System
Authors: Wang Gao Ping , Hong Yong , Hong Dong Pyo , Yang Sung Mo , Kim Young Moon
Published: March 2009

Pieces of large-scale equipment such as a ball mill system are subjected to heavy and
alternate loads under the worst working conditions, which result in higher fault rates. However,
since such equipment exerts important functions to the economy and industry, it isn’t
recommendable to halt production in order to detect the defects under unconfirmed faults. We
explore a reliable and practical fault diagnosis scheme for the ball mill system that is widely used in
the building material industry. With utilizing the signal acquisition and process system of vibration,
the field testing and analysis are performed based on the violent vibration of an edge-transmission
Φ3×11m ball mill system. The primary diagnosis that is based on the configuration of the
transmission system and foundation stiffness is found, and a feasible resolution scheme is obtained,
so that the optimal and economic reform scheme is determined. The detailed scheme has been
adopted by the production industry. This study that is based on the fault diagnosis of the edgetransmission
ball mill system has a comprehensive significance of theory and reality. This provides
a larger basis for vibration inspection and fault diagnosis in building material industries.
Coupling Analysis of Fluid Film and Thermal Deformation of Sealing Members in Spiral Groove Mechanical Seal
Authors: Zhou Jian Feng , Gu Bo Qin
Published: March 2009

The thermo-hydrodynamic effect in the spiral groove mechanical seal was investigated.
The coupling analysis of the fluid film and the thermal deformation of sealing rings was carried out,
the separation angle obtained, and the shape of the gap between the two deformed end faces
determined. The results indicate that the increase of the temperature of the fluid film and the
thermal deformation of the sealing rings cause the increase of the leakage rate. There exists a
critical rotating speed, when the rotating speed is lower than the critical speed, the bearing force
increases with the increase of the rotating speed, and once the rotating speed is higher than the
critical speed, the bearing force decreases reversely. The thermal deformation weakens the
hydrodynamic effect of the spiral groove mechanical seals.
Probabilistic Cyclic Constitutions and Design Curves of 0Cr18Ni10Ti Pipe Steel
Authors: Zhai Zhong Yan , Feng Ming Fei , Zhao Yong Xiang
Published: March 2009

Probabilistic cyclic constitutions are investigated and safety assessment on the ASME
code-based design curves is given to 0Cr18Ni10Ti pipe steel. Incremental and group fatigue tests
were carried out respectively to reveal the cyclic deformation and life characteristics. The results
showed that the material acted as cyclic strengthening and masing behaviour. A phenomenon of
random cyclic constitutions was observed. The modified Ramberg-Osgood equation combining an
assumption of the cyclic stress amplitude following normal distribution is applied to describe the
constitutions. Fine modeling effect is obtained on both considerations of survival probability and
confidence. Probabilistic characteristics are also given to the fatigue virtual stress amplitude-life
relations and then a safety assessment is carried out on the design curves. The results exhibit that the
ASME curves with constant reduction factors are not matching the evolutionary scattered statistical
trend of fatigue lives. The curves with 2 reduction factor on stress amplitude and 20 on fatigue life are
much conservative for the present material, which is great different from the previous observation to
weld metal. It indicates that the fatigue design by analysis for the piping should be based appropriately
on the welded joint data.
A Statistical Load Weighted Average Fatigue Reliability Model for Uncertain Constant Amplitude Cyclic Load
Authors: Xie Li Yang , He Xue Hong
Published: March 2009

The present paper interpreted the traditional stress-strength interference model as an
equation expressing the statistical average of the probability of strength preponderating over stress.
Thus, the same equation, which was traditionally applicable only in the situation of same-measure
parameters, can be applied to more general situation of different-measure parameters. In other words,
the traditional model was extended to the situation of any two variables, as long as one variable can
be expressed as a function of the other. With a specific load amplitude distribution, the method is to
calculate the statistical average of the probability that fatigue life random variable under the
individual constant amplitude cyclic load is greater than an assigned value. The extended
interference analysis method can be applied directly to calculate fatigue reliability under constant
amplitude cyclic load with uncertainty in the stress range.
Effects of External Loads on the Reliability of Welded Pipe with Circumferential Crack
Authors: He Bo Lin , Yu Ying Xia , Huo Li Xing , Zhang Yu Feng
Published: March 2009

The reliability of welded pressure pipe with circumferential surface crack was calculated by
using 3-D 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 3-D elastic-plastic stochastic finite element program which was developed by ourselves.
The effects of variables such as bending moment, the inner pressure on the structure reliability were
discussed. The calculation results indicate that the bending moment has great effect on the reliability of
the welded pipe, and the inner pressure has little effect on the reliability of the welded pipe if the inner
pressure is less than 10MPa. If the mean value of the inner pressure changed from 0.5MPa to 30MPa, the
failure probability will changes from 10-6 to 10-2. The bending moment also has great effect on the
reliability. When the mean value of moment is changed from10000 Nm to 15000 Nm, the failure
probability of the welded pipe increases dramatically for the same inner pressure. Irrespective of the
changing of moment, the pipe has higher reliability if the inner pressure is less than 6 MPa. The method
has put forward a new way for safety assessment of welded pipe with circumferential surface crack.
Mechanical Reliability of a Segmented Silicon Layer on Ultra-Thin Polyimide Substrates
Authors: Wang L. , Xiao A. , Jansen K.M.B. , Bartek M. , Zoumpoulidis T. , Ernst L.J. , Zhang G.Q.
Published: March 2009

Substrate transfer technology for SOI and non-SOI single-crystalline silicon wafers was
demonstrated allowing for high-performance low-power RF applications. 3D deformable electronics
could be realized by vertically thinning and laterally partitioning of the silicon substrate on
sub-millimeter scale. By varying the partition dimensions and the geometry of connecting bridges, the
level of acceptable deformations can be controlled. The targeted applications of this technology are
wireless ID tags and sensor networks. The mechanical properties such as crack, interfacial
delamination are critical to reach the flexible substrate. In this contribution, results of our work on
mechanical reliability issues of poly- and single crystalline silicon on ultra-thin polyimide substrates
are presented. To improve reliability, square and hexagonal segmentation with different size is
applied to the silicon layer before it is transferred onto an ultra-thin polyimide substrate using
wafer-to-wafer substrate transfer technique based on a temporary glass carrier. Generation of cracks
within the silicon and dielectric layers is then studied under controlled bending and tensile loads. The
formation of cracks is studied experimentally using specially for this purpose designed bending and
tensile tools. Ultra-thin interfacial delamination are also focused in this work by experimental and FE
simulation method. A new test setup is designed for mixed mode bending testing which has capacity
to observation specimen and recording the crack length and crack opening by microscope. The critical
energy release depended on mixed angle can be reach by combination experimental data with FEM
simulation.
Study on the Relationship of Hydrogen Content and Ultrasonic Propagation Properties
Authors: Zhang Lei , Tang Shi Hua , Pan Hong Liang
Published: March 2009

Hydrogen-induced corrosion is a common damage in petrochemical industry. It can rise
crack and bubbling on the surface of metal materials when the hydrogen corrosion is in the stage of
severity. In the present, it is hard to evaluate the material conditions nondestructively under
hydrogen attack. In this paper, the possibility of the relationship between ultrasonic propagation
properties and the content of hydrogen corrosion was investigated. We have found that the surface
wave velocity is a parameter, which can be directly correlated with the hydrogen content. The
sensitivity has been found to be acceptable.
Influence of Different Loading Modes on Rock Tensile Strength
Authors: Wang Ru , Tang Chun An , Wang Shu Hong , Wang Zhi Yuan , Ma Tian Hui
Published: March 2009

A typical mechanical character of rock is that the tensile strength is far less than the
compressive strength. Meanwhile, the test data of tensile strength is very dispersive. Because the
direct tensile tests always result in failure due to the difficulty in clamping the rock sample, the
splitting test is used to determine the tensile strength of rock. There are four kinds of loading modes
in the splitting test in actual laboratory test: angle pad splitting, round pad splitting, aclinic loading
platen splitting, arc loading platen splitting. In this paper, the direct tensile test, the splitting test and
the influence of different loading modes on rock tensile strength were studied. In order to study the
stress distribution, the progressive splitting failure process was numerically modeled under the four
kinds of loading cases by the Realistic Failure Process Analysis code (RFPA2D). Results show that
the stress states under angle pad splitting, round pad splitting are similar to the stress states under
diametrical compressive state. Regarding that the round pad splitting test is easy to implement, and
its numerical results are also stable relatively, the round pad loading mode was suggested to be
adopted.
Damping Analysis of Asymmetrical Comb Accelerometer
Authors: Chen Wei Ping , Zhao Zhen Gang , Liu Xiao Wei , Lin Yu Min
Published: March 2009

The resonance phenomenon is suppressed by adjusting the damping of the comb
accelerometer structure to widen the frequency bandwidth of the capacitive accelerometer. The
capacitive accelerometer with asymmetrical combs, fabricated with DRIE and anodic bonding, is
presented. The damping category of the accelerometer is introduced, in which the squeeze-film
damping coefficient and the damping ratio factor are detailed. The damping ratio factor of the
accelerometer, measured by a vibration method, is 0.17. The damping ratio factor of the optimized
structure is calculated of 0.15 to 0.18 with the change of experiential modulus C from 25 to 30,
theoretically.
A Simple Spline Integral Equation Method for Circular Plates with Variable Thickness
Authors: Zhou Xin Zhu , Zheng Jian Jun
Published: March 2009

A simple spline integral equation method is presented in this paper for the
axisymmetrical bending of circular plates with variable thickness. Firstly, the fundamental solution
of a second-order differential equation is derived. With the slope of the deflection surface taken as
an unknown function, an integral equation is then established for circular plates with variable
thickness. The integral equation is solved numerically by cubic spline interpolation and the
deflection and bending moment at any point within the circular plate are obtained. Finally, the
validity of the proposed method is verified with the analytical solution obtained from the literature.
Uniform Wearing Optimum Design of Extrusion Die Profile
Authors: Wang Lei Gang , Sun Xian Ping , Huang Yao
Published: March 2009

Die wear is regarded as a crucial factor which affects die life and quality of products. In
hot extrusion process, finite-element method (FEM), BP neural network and genetic algorithm were
combined together to optimize extrusion die profile which yielded more uniform wear depth
distribution on die profile. A method of B-spline function interpolation was used to describe
extrusion die profile. The temperature, pressure and velocity field of nodes that lied on extrusion die
profile were gained by FEM simulation. Wear depth of extrusion die profile was calculated by
modified Archard theory. The results were used to train BP neural network, so that nonlinear
mapping relations between reference points of die profile and wear depth were obtained. In order to
gain uniform wear depth, genetic algorithm was applied to optimize extrusion die profile. Optimum
result, compared with common conical die profile, reduced wear depth of extrusion die and
improved service life. At the same time, the optimal result accorded with practical conditions.
A New Numerical Method for Axisymmetrical Bending of Circular Plates with Large Deflection
Authors: Zheng Jian Jun , Zhou Xin Zhu
Published: March 2009

A simple and efficient spline integral equation method is presented in this paper for the
axisymmetrical bending of circular plates with large deflection. Based on two second-order
differential equations in terms of the slope of the deflection surface and the radial displacement of
the circular plate, two integral equations are derived. The circular plate is then equidistantly divided
into a circular plate element and a series of annular plate elements along its radial direction and the
slope of the deflection surface and the radial displacement are both approximated by cubic spline
interpolation. The two integral equations are solved numerically and the displacements and internal
forces at any point within the circular plate can be obtained. Finally, some numerical results are
presented for illustrating the validity of the proposed method. It can be concluded that the proposed
numerical method can be used to analyze circular plates with large deflection with reasonable
accuracy.
Effect of Physical Property of Water on SCC Growth Rate of 316L Stainless Steels in High-Temperature Water
Authors: Abe Hiroshi , Watanabe Yutaka
Published: March 2009

A number of mechanisms have been proposed to understand stress corrosion cracking
(SCC) of metals, e.g. (1) slip dissolution and active pass corrosion based on anodic dissolution of
metals, (2) tarnish rupture and internal oxidation based on oxidation ahead the crack tip followed by
cracking of the oxides, and (3) hydrogen cracking, etc.
If dissolution of metals takes the essential role in the stress corrosion cracking concerned,
cracking susceptibility is expected to be significantly affected by dielectric constant of water.
Because dielectric constant represents a character of water as a solvent, which determines solubility
of metal oxides, and therefore corrosion rate of metals is strongly dependent on dielectric constant
of water.
K-constant type SCC growth rate tests have been done as a function of physical property
(dielectric constant) of water by either manipulating temperature under iso-pressure condition
(15MPa) or manipulating pressure under iso-thermal condition (330oC). Intergranular cracking was
more enhanced and the crack growth was significantly accelerated under the condition of higher
dielectric constant, indicating that dissolution of metal plays important role in the cracking
mechanism of 316L stainless steels under the present testing conditions.
12Finite Element Analysis of an Automobile Clutch System
Authors: Lee Choon Yeol , Chung Il Sup , Chai Young Suck
Published: March 2009

A pressure plate, a component of the clutch system, was analyzed by two-dimensional and
three-dimensional finite element method under three major load conditions of thermal loading due to
temperature distribution, centrifugal force and contact pressure of diaphragm spring. The results show
that the effects of thermal loading and contact pressure of diaphragm spring are important, which
suggests the direction of design improvement. A hub plate was also analyzed with finite element
modeling. A stress concentration occurs around the fillet region around the window in the plate where
the fracture analysis is executed to find the stress intensity factors. These results will be used as the
fundamental data for design improvement of the shapes of pressure plates and hub plates.
Fatigue Properties of Spherical Graphite Iron Crankshafts
Authors: Ma Ming Tu , Li Zhi Gang , Yi Hong Liang , Zhang Hao
Published: March 2009

The crankshafts of semi-finished products were manufactured by two processes: as-cast
followed by normalizing and iron mould with sand liner as-cast. Then those were machined and
nitridized followed by the bending fatigue test. At last mechanical properties and impact properties of
sampled crankshafts were tested. The mechanical properties are similar in the crankshafts treated by
both of the processes, however, the bending fatigue limits of as-cast spherical graphite iron
crankshafts are much higher than that of normalized spherical graphite iron crankshafts, whose crack
producing work and extending work is higher as well. The higher extended work is considered to
relate to the oeil-de-boeuf ferrite and graphite structure and pearlite in as-cast spherical graphite iron
crankshafts, while the normalized ones with lower fatigue limit value are composed of spherical
graphite and pearlite. Cracks having initiated in the graphite, the tips of cracks can be blunted and the
crack propagation can be impeded efficiently by ferrites surrounding the graphite in this structure.
Influence of Deposition Bias Voltage on Fatigue Cracking Behavior of Chromium Nitride Film Deposited on Steel
Authors: Yonekura Daisuke , Fukuda Huriyzju , Murakami Riichi
Published: March 2009

Three point bending fatigue tests were carried out to investigate the influence of bias
voltage on fatigue behavior of medium carbon steel with chromium nitride film. The substrate
material of the specimens was JIS S45C medium carbon steel. The chromium nitride films were
coated at two different bias voltages (VB = -20V, -300V) for fatigue test by arc ion plating method. As
a result, the fatigue limit was improved by coating at low bias voltage, while the fatigue limit of high
bias voltage samples decreased by coating.
In order to clarify the difference between high and low bias voltages, the tensile test was performed
using the coated specimens. For this test, the chromium nitride films were deposited at four different
bias voltages. It was found the cracking behavior clearly changed between -40V and -80V. For low
bias voltage samples, short cracks were initiated in the films, while the long cracks were initiated at
same strain for high bias voltage samples. These differences between low and high bias voltage
sample may be due to the elastic modulus of the film and droplets distribution in the film.
Application of Data Mining Technology in Structural Strength Design
Authors: Wang Lei , Li Jia , Wang Chen Gen
Published: March 2009

Based on neural networks, the present paper gives an engineering application of data
mining. The back propagation (BP) neural network is used as the algorithm of data mining. Then
the effects of structural technologic parameters on stress in the weld region of the shield engine rotor
in a submarine are analyzed. The mined data come from the numerical simulations of the finite
element method. The effects of different parameters on the stress in the weld region are achieved
from the results of the data mining. The discovered knowledge is beneficial to the security improvement
of structural strength design for the engine rotor.
Square-Structure Estimation of Bolt Fastening Conditions with Using PZT Patches
Authors: Hong Yong , Han Byeong Hee , Hong Dong Pyo , Yang Sung Mo , Kim Young Moon , Kim Kyeong Suk
Published: March 2009

This paper describes a primary study for a new method of enhancing measurement with
using an impedance analysis method that is applied to structural health monitoring. The goal of this
research is to show basic information that is used to evaluate the structural health condition with
using piezoelectric sensors. We present a study for the development of a practical and quantitative
technique for the assessment of the structural health condition with using a piezoelectric
impedance-based technique that is associated with longitudinal wave propagation. The natural
frequency has a tendency of frequency shifting with respect to the hole size that corresponds to the
real structure’s crack size. To numerically estimate the damage condition, we suggest the Cov
(Covariance) and CC (Correlation Coefficient) evaluation methods.
Codes and Practice of Fatigue Design for Welded Structure
Authors: Sakamoto Haruo
Published: March 2009

This paper describes codes and practice for designing welded structures such as railroad
truck frames. For designing an initial configuration, rather simple criteria are desired, although most
codes such as AWS, AISC, etc. are complex. They consist of a variety of welded joint categories,
which make a designer feel difficult when deciding the initial configuration. Therefore, such codes
are considered to be mainly used for the evaluation of designed and constructed structures, and not
to be used for deciding the initial configuration. The JIS (Japanese Industrial Standard) for a railroad
truck frame is explained as an example of a simple code, and is compared with some fatigue data.
This standard is thought to be useful for a designer. However, the result of this investigation
suggests a modification of the JIS for obtaining more reasonable criteria.
Desirable criteria should be simple for a designer and sufficiently safe for structures. Additional
fatigue data of welded joints, a statistical study for desirable non-fracture probability, and methods
of structural stress analysis are to be researched in the future. A practical fatigue testing method is
also needed for investigating the strength in a high cycle region such as 108.
Optimum Design of a Dynamic Micro-Mixer for Multiphase Flow
Authors: Han Seok Young , Park J.Y. , Kim Y.D. , An S.J. , Maeng J.S.
Published: March 2009

An active micro-mixer equipped with an oscillating stirrer is considered by analyzing the
mixing behaviors, i.e. the effect of the Karman vortex, the flow structure after the stirrer, etc. The
mixing was calculated by the D2Q9 model of Lattice Boltzmann methods. In this study, the time–
averaged mixing index formula, I D , is newly proposed for time dependent flow. Three models are
tested and the mixing indices are compared. From the results, it was found that the mixing of Model
III is enhanced and stabilized much more than the other models. Therefore, an optimum design for a
dynamic micro-mixer with an oscillating stirrer was performed. The design variables were
established as the length, the angle and frequency of the stirrer. It is found that the optimal design
variables are determined by 0.66, 107.9 o and 0.49 Hz.
Axiomatic Design of a Spatial Micromanipulator and Experimental Verification
Authors: Han Seok Young , Yoon S.J. , Kim S.R. , Park J.Y. , Yi Byung Ju , Kim S.J.
Published: March 2009

The micromanipulator is basically required sufficient workspace and high natural
frequency. However, previous designs are hard to satisfy the required workspace and natural
frequency simultaneously. In this study, a previous design was analyzed from the viewpoint of the
axiomatic design. Then, a new design parameter as displacement amplifier which transforms a
coupled design into a decoupled design, was suggested. And a design procedure based on axiomatic
design was developed. A spatial 3-DOF parallel-type micromanipulator was chosen as an exemplary
device. According to the suggested design procedure, the micromanipulator having the required
natural frequency was designed in the first step, and then the displacement amplifier satisfying the
required work space was designed sequentially. To check the effectiveness of the manipulator and
displacement amplifier, simulations and experiments were performed. Those are verified that the
displacement amplifiers implemened work very well for satisfying the required task workspace.
Topology Optimization of the Inner Reinforcement for a Vehicle’s Hood Using Smoothing Scheme
Authors: Choi S.H. , Kim M.S. , Hwang J.S. , Park J.Y. , Han Seok Young
Published: March 2009

Topology optimization of the inner reinforcement for a vehicle’s hood has been
performed by evolutionary structural optimization (ESO) using a smoothing scheme. The purpose of
this study is to obtain optimal topology of the inner reinforcement for a vehicle’s hood considering
the static stiffness of bending and torsion, and natural frequency simultaneously. To do this, the
multiobjective optimization technique was implemented. Optimal topologies were obtained by the
ESO method. From several combinations of weighting factors, a Pareto-optimal solution was
obtained. Also, a smoothing scheme was implemented to suppress the checkerboard pattern in the
procedure of topology optimization. As the weighting factor of the elastic strain efficiency goes
from 1 to zero, it is found that the optimal topologies transmits from the optimal topology of static
stiffness problem to that of natural frequency problem. Therefore, it is concluded that ESO method
with a smoothing scheme is effectively applied to topology optimization of the inner reinforcement
of a vehicle’s hood considering the static stiffness and natural frequency.
The Mechanisms Analysis of the ACF Bonding Strengths after the High Temperature/ Humidity Environment Test
Authors: Zhang Jun , Chen Xu , Wei Xin Li , Lin Yong Cheng
Published: March 2009

The environmental experiments of the thermal cycling (-40~125°C) and the high
temperature/humidity (85°C, 85%RH) aging were used to evaluate the reliability of the specimens
bonded with ACFs. It was found that the high temperature/humidity was the harshest condition to
the ACFs bonding. The DSC testing and interfacial stresses analysis has been done under the high
temperature/humidity condition. The mechanisms of the bonding strength decrease were
investigated.
Study on the Service Life of Electronic Equipment
Authors: He Yu Ting , Li Hong Peng , Li Feng , Fan Chao Hua
Published: March 2009

Based on the analyses of reliability and life characteristics in electronic equipment, a new
concept of Electronic Equipment Life Envelope (EELE) is presented. The basic approach to EELE
establishment is investigated in detail. The interrelationship between storage life and working life of
electronic equipment is demonstrated by virtue of EELE, which validates its preliminary application
and advantages. The new philosophy can be further applied to accelerated experiments and service
life prediction for electronic equipments.
Isothermal Aging Effects on the Microstructure, IMC and Strength of SnAgCu/Cu Solder Joint
Authors: Li Xiao Yan , Yang Xiao Hua , Dui Wei Zhen , Wu Ben Sheng
Published: March 2009

The formation and evolution of the intermetallic compound (IMCs) between SnAgCu
lead-free solder and Cu substrate, after isothermal aging at 150°C for 24, 48, 120, 240 and 480
hours, were studied. Scanning electron microscope (SEM) was used to observe the microstructure
evolution of solder joint during aging. The IMC phases were identified by energy dispersive X-ray
(EDX). The results showed that IMCs layer of Cu6Sn5 was formed at the interface of solder and Cu
during reflowing. With the increase of aging time, the grain size of the interfacial Cu6Sn5 increased
and the morphology of the interfacial Cu6Sn5 column was changed from scallop-like to needle-like
and then to rod-like and finally to particles. At the same time, the rod-like Ag3Sn phase formed at
the interface of solder and the IMCs layer of Cu6Sn5 with the aging time increased. In addition,
large Cu6Sn5 formed in the solder with the aging time increased. The tensile strength was measured
for the solder joints. The results showed that the tensile strength increases slightly at beginning and
then decreases with the aging time. SEM was used to observe the fracture surface and it showed that
the fracture position moved from solder matrix to the interfacial Cu6Sn5 IMCs layer with the aging
time increased. The weakening of the solder matrix is caused by the coarsening of the eutectic
solder structures. The weakening of the interfacial IMCs layer is caused by the evolution of
morphology and size of the interface Cu6Sn5 layer.
Shape Prediction and Reliability Design of Ball Grid Array Solder Joints
Authors: Tian Yan Hong , Wang Chun Qing
Published: March 2009

Reliability optimization design of Ball Grid Array (BGA) solder joints is a major concern
in area array electronics packaging technology. In this paper, shapes of the solder joints and their
reliability were predicted and analyzed. Through the variations of lower pads’ diameters, the shapes
of full array BGA solder joints with different solder volumes were predicted by using surface evolver
software. Based on the results of shape prediction, 3-D finite element models were established with
MSC.MARC and the distribution of the stress and strain in the BGA solder joints under thermal
cyclic loading were simulated. Finally, fatigue lives of the BGA solder joints with different solder
volumes were calculated, and the diameter ratios of lower pad to upper pad for these two kinds of
BGA assemblies with the best reliability were optimized.
Effects of Microstructures on Strength and Fatigue Properties of Long-Term-Serviced F12 Steels
Authors: Wu X.M. , Zhang G.P. , Zhang J.Q. , Chen W.G.
Published: March 2009

Microstructures of long-term serviced F12 steel exposed at 545 °C have been investigated
by electron microscopes. The hardness of the material was measured to be correlated with the
variation of the microstructures. Fatigue properties of the material with different running time were
evaluated and analyzed. The experimental results show that the coarsening of the precipitated
carbides along boundaries and the formation of subgrains accelerate the degradation of the long-term
creep properties of the steel. Fatigue crack initiation threshold from a notch linearly deceases with
increasing the running time due to the variation of the distribution and the shape of the precipitated
carbides. The degradation mechanisms of the F12 steel during their long-term service at high
temperature are discussed.
Effect of Spring Pressure on Basic Performance of Contacting Mechanical Seals
Authors: Sun Jian Jun , Gu Bo Qin
Published: March 2009

While the fact that abrasion leads to change of surface topography is taken into
consideration, the influence of spring pressure both on leakage rate and on friction characteristic of
contacting mechanical seals are investigated by fractal theory. Several GY-70 type mechanical seals
are tested. Both theoretic analysis and test results indicate that the friction will be more serious
because lubrication medium between two end faces reduces as spring pressure increases, though the
increase of the spring pressure may not be enough to change the face friction state of mechanical
seal. There is an optimum spring pressure for mechanical seal operation. Under different operating
conditions, identical type mechanical seals may possess different spring pressure. Appropriate
selection of spring pressure is key to the mechanical seal operation under the best condition.
Analysis of Valence Electron Theory on the Catalytic Mechanism of Diamond Single Crystal Growth
Authors: Li Li , Xu Bin , Li Mu Sen , Gong Jian Hong
Published: March 2009

Large numbers of experimental results show that carbides Me3C (Me means Fe, Ni, Co,
Mn) are the primary carbon source to form diamond structure under the high temperature and high
pressure (HPHT). In this paper, based on the empirical electron theory of solids and molecules (EET),
the valence electron structure (VES) and interface structure factors of diamond and various carbides
are calculated, and the boundary condition of electron movement in the improved Thomas-
Fermi-Dirac theory by Cheng (TFDC) is applied to the carbide/diamond interfaces. It is found that the
electron density of crystal plane in Me3C formed by C-C bonds is continuous with that in diamond at
the first order of approximation. Compared with Ni-based carbides [Ni3C, (NiMn)3C)], the electron
density difference of Fe-based carbides [Fe3C, (FeNi)3C, (FeMn)3C]/diamond interfaces is lower, and
that of (FeNi)3C/diamond interface is minimum. The results show that the energy needed to transform
carbon atomic groups into diamond structure is lower for Fe-based carbides than Ni-based carbides.
The Abnormal Viscosity Variation Behavior of Melt Bi
Authors: Geng Hao Ran , Sun Chun Jing , Chen Guang Li , Ji Lei Lei
Published: March 2009

The viscosity-temperature curve of Bi melt showed that the viscosity values deceased
with the increase of temperature. However, the discontinuous changing pattern took place on the
viscosity curve. Viscosity of Bi melt can be divided into three parts as high temperature zone,
moderate temperature zone and low temperature zone according to its change rate with temperature.
The temperature ranges of the abnormal viscosity change were about 400~430°C and
610~640°C. With the DSC analysis, the abnormal phenomenon was explored from the
microscopic structure viewpoint. It was assumed that the change from inhomogeneous atom
configuration to homogeneous one led to the discontinuous variation, which is related to the bond
transformation with the increase of temperature in melt Bi.
Modeling of the Effect of Excavation Mode on the Extent of the Anisotropic Zone Surrounding Deep Tunnels
Authors: Wang Shu Hong , Zhang Juan Xia , Tang Chun An , Wang Shan Yong
Published: March 2009

A series of numerical model tests were performed to investigate the behaviour of the
anisotropic rock surrounding circular excavations under high confining pressures. The aim was to
provide information on the formation of fractures and failure around deep level rock tunnels under
controlled conditions. Solid cubes containing a circular hole were confined to a vertical pressure with
same as the confinement in the horizontal directions. In this modeling, the inhomogeneous rock is
generated by using Weibull parameters which are related to the microstructural properties determined
by crack size distribution and grain size. The fracture angle is assumed to be 45o. The observed failure
zone around the excavation was simulated using both the maximum tensile strain criterion and
Mohr-Coulomb criterion respectively (as the damage threshold). And RFPA (Realistic Failure
Process Analysis) code was used as the calculating tool in this modelling, three opening modes are
simulated and compared. Computational model predictions that include crack propagation and failure
modes of rock show a good agreement with those of the observation in site. It is pointed out that the
damage evolution of EDZ strongly depends on the inhomogeneous, the excavation mode, anisotropic
property, and the various loading conditions. Concerning the existence of a weak plane, the amount of
displacement at the side wall of the tunnel was quite large, since the shear deformation occurred in
EDZ. The model is implemented in RFPA code and is able to represent the change in fracture patterns
between the solid and jointed parts. This provides confidence for the application of the numerical
model to the design of rock tunnels at great depth.
Analysis on the Gravel Stratum Deformation by Dewatering
Authors: Zhao Wen , Xu Yan , Sun Hai Xia
Published: March 2009

Large particle-size, shallow groundwater level, and large permeate coefficient are the
characteristics of gravel stratum, which may results in large ground deformation. Ground deformation
depends on several factors. Using the RFPA2D-Flow software exploited by the Center for Rock
Instability and Seismic Research of Northeastern University (CRISR), the seepage-stress-deformation
coupling rules of soil, which are influenced by different soil distributing, drawdown, enclosure and
excavating, were analyzed, and the deformation of gravel in the dynamic balance due to the
interaction between seepage and stress is studied.
The Deformation of Discontinuity in the DDA Method
Authors: Liu Jun , Li Zhong Kui
Published: March 2009

The DDA method parallels the finite element, which solves a finite element type of mesh
where all the elements are bounded by discontinuities. In the current studies on the DDA method, the
deformation of all the discontinuities is neglected, only the deformation of blocks is concerned with.
The actual engineering indicates that the deformation of control discontinuity is often greater than that
of block, and can not be neglected; but the deformation of the smaller discontinuities may be
neglected. In this paper, the deformation of discontinuity is studied, and the result indicates that the
displacement and stress of block element are affected by the deformation of discontinuity to a degree.
Therefore, the deformation of control discontinuity can not be neglected in the study of the DDA
method.
Investigation on Friction and Thermal Expansion Coefficients of Al-Sn Bearing Alloys
Authors: Zou Yong Zhi , Xu Zheng Bin , Gao Yan , Gu Hong , Zeng Jian Min
Published: March 2009

The influences of Sn addition of 3%-30% on the friction and thermal expansion properties
of Al-Sn bearing alloys were investigated in this paper. The experiments were carried out on a
specially designed friction testing machine and a dilatometer. It is shown by the experiments that the
friction coefficient and hardness of the alloys decrease with the increasing of Sn content. The friction
coefficient decreases dramatically when Sn content is higher than 6%. On the other hand, the friction
coefficient is also dependent on the load. The friction coefficient increases as the load rises. The linear
CTE is also a function of temperature and Sn contents. CTE increases when the temperature rises but
has no obvious differences for the alloy system when the temperature is below 80°C. As the
temperature rises, the differences become large among the alloy system. The higher the Sn content,
the lower the CTE.
Structural Human Impact Analysis on Shooting: Experimental and Simulation
Authors: Lee Young Shin , Lee Se Hoon , Choi Young Jin , Chae Je Wook , Choi Eui Jung
Published: March 2009

On the human-rifle system, the human body is affected by the firing impact. The firing
impact will reduce the firing accuracy and change the initial shooting posture. Therefore the study of
biomechanical characteristics using human-rifle modeling and numerical investigation is needed. The
muscle-skeleton model was developed by the finite element method using beam and spar elements. In
this study, a structural analysis has been performed in order to investigate the human body impact by
firing a 5.56mm small caliber machine gun. The firing experiments with a standing shooting posture
were performed to verify analytical results. The result of this study shows analytical displacements of
the human-rifle system and experimental displacements of real firing. In the results, the analytical
displacement on the human body is presented.
Computer-Aided Optimized Design for Multi-Alloyed Steels Specifying Hardenability Requirements
Authors: Song Yue Peng , Zhang Xiao , Liu Guo Quan
Published: March 2009

The Jominy end-quench curves of non-alloyed and alloyed steels can be predicted by
nonlinear equation method. Without considering the interaction effects of alloying elements on the
curves, however, the prediction for multi-alloyed steels may be different markedly from that
experimentally determined. Hence, an improved mathematic model for predicting the Jominy
end-quench curves of multi-alloyed steels was proposed by introducing a parameter named
“alloying element interactions equivalent” to the nonlinear equations. With the improved model, the
predicted Jominy curves agree very well with the experimental ones for more than 300 steel grades
found in the literature. A computer-aided design system for hardenability of structural steels was
then developed. The system not only can quantitatively evaluate the hardenability of structural
steels, but also is very helpful to design steels and hardenability-aimed components. The optimal
composition range of a new steel was so successfully designed as an example. Further research
results show that the computer-aided design system so developed can also be used for monitoring of
hardenability variation in steel industrial production.
Influence of the Various Li/Nb Ratios on Defect Structure and Photorefractive Properties of In: Eu: Fe: LiNbO3 Crystals
Authors: Sun L. , Guo F.Y. , Lv Q. , Li Hong Tao , Cai Wei , Xu Y.H. , Zhao Lian Cheng
Published: March 2009

In: Eu: Fe: LiNbO3 crystals were firstly grown from a congruent melt according to the
Czochralski method, with the various ratios of Li/Nb =0.885, 0.946, 1.051. The new crystal
composition and defect structure were analyzed by the UV-Vis spectroscopy. In the two-wave
coupling experiments, writing and erasure time, maximum diffraction efficiency, photorefractive
sensitivity and dynamic range were measured and calculated. The dependence of the
photorefractive properties on the defect structure of In: Eu: Fe: LiNbO3 Crystals were discussed.
Pure Bending Testing of Cr-Mo Alloy in Metal Dusting Condition
Authors: Xu Tao , Tu Shan Tung , Song Hong Jian , Gong Jian Ming
Published: March 2009

Metal dusting is a catastrophic corrosion phenomenon that leads to the disintegration of
structural metals and alloys into dust composed of fine particles of the metal/alloy and carbon at high
temperature. Considerable research efforts has been taken on the initiation of metal dusting in the
alloy since it was observed. However, the previous researches were focused mostly on the initiation
mechanisms of metal dusting without external applied loads. In fact, structural materials are mostly
used with external applied loads. It is thus necessary to study the initiation and propagation
mechanism of metal dusting in the stressed condition. In the present work pure bending testing of
Cr-Mo alloy in metal dusting condition was performed. The laboratory experiments were performed
at 560°C, using a synthesis gas mixture with composition 75%H2 + 25%CO. The maximum bending
stresses were 100MPa, 50MPa, 10MPa and 0MPa, respectively. Post exposure metallographical
examinations, SEM, EDX analysis were made in order to identify the difference between loaded and
unloaded specimens. The effect of mechanical and chemical interaction on high temperature
corrosion was preliminary discussed.
Study on Strengthening of the Solid Contact Alloy CuW80/Cu
Authors: Huang You Ting , Yang Kai Huai , Tang De Ping , Chen Wen Zhe
Published: March 2009

The strengthening effects of the Cu-80 wt.% W (CuW80) alloy and the copper parts in
Cu-80wt.% W /Cu (CuW80/Cu) solid contact alloy, which was sintered and infiltrated prepared
by powder metallurgy, were investigated. The effects of different compressive deformation on
microstructure and properties of the CuW80 were studied. Furthermore, the influences of
HextrusionH on copper parts, the carrier material of the solid contact alloy CuW80/Cu were also
investigated. The results show that the tungsten and copper phases are closely bonded by physical
bond in the form of pseudo-alloy and the copper phase is homogeneously dispersed within the
tungsten framework. The hardness of the CuW80 increases with increasing compressive
deformation. Especially, the hardness of the copper parts in CuW80/Cu increases remarkably after
extrusion and the maximum value can reach 200%. The hardness increases from the inner to the
surface and is proportional to the distance departing from the interface of the CuW80 and Cu.
TEM observation shows that the dislocation tangles exist, even inside the dislocation cell, in
copper grains after extrusion.