bluuebunny/crossref_metadata_2025 huggingface dataset:
Low-Cycle Fatigue Life Prediction by a New Critical-Plane Method
Authors: Jin Dan , Wu Jian Hua , Zhang Yang
Published: March 2009

A series of low-cycle fatigue experiments of axial-torsional loading of variable
amplitudes were performed on the tubular specimens of 304 stainless steel. Two models of
multiaxial low-cycle fatigue life, KBM and FS method, are evaluated based on the fatigue life data
of 304 stainless steel. Rainflow cycle counting and the Liner Damage Rule are used to calculate
fatigue damage. It was shown that the part prediction results are nonconservative for the two models.
The life prediction is done again based on the weight function critical plane method for the two
models. The prediction results are better by using the weight function critical plane method than the
previous results for KBM model. But the prediction results are improved little for FS model in spite
of the weight function critical plane method being used.
Numerical Simulation on Mixed Mode I-II Crack Propagation Process in Concrete
Authors: Xu Qing , Dong Wei , Wu Zhi Min
Published: March 2009

A crack propagation criteria is proposed for mixed mode I-II fracture in concrete based on the initial cracking KⅠ-KⅡ curve obtained from experiment. Once the difference between the stress intensity factor at the crack tip caused by the external load and the one caused by the cohesive force attains the above KI-KII curve, the crack begins to propagate. Based on this criteria, the finite element method was used to simulate the mixed mode I-II crack initiation, stable propagation and unstable failure in concrete. For the four-point shear concrete specimens, the crack propagation trajectory and P-CMSD (Crack Mouth Sliding Displacement) curve were obtained. Upon the comparison with the experimental results, the calculated results show good agreement. It is concluded that, if the elastic modulus E, the uniaxial tensile strength ft and the initial cracking KI-KII curve of concrete are measured from experiment, the complete process of mixed mode I-II crack propagation can be simulated using the proposed criterion.
Optimum Dimensions of Thin Walled Tube on the Mechanical Performance of Super Stud Bolt
Authors: Xiao Yang , Kuhara Masahiro , Noda Naoaki , Saito Kinjiro , Nagawa Masato , Yumoto Atsushi , Ogasawara Ayako
Published: March 2009

The bolts and nuts are widely used in various fields as important joining elements with
long history. However, loosening induced by the vibration and external loads is still a big problem.
And the loosening sometimes causes very serious accident without notice. This paper deals with a
special stud bolt named “Super Stud Bolt (SSB)” which can prevent loosening effectively. There is
a thin walled tube between the upper and lower threads, which can be deformed along the axial
direction so that the phase difference is produced and SSB is developed. This phase difference
induces the contrary force on the surfaces of the upper and lower threads, which brings out the
anti-loosening performance. In this study, the processing and fastening-loosening courses are
simulated with the finite element method. And the anti-loosening performance is analyzed and
realized. In addition, the anti-loosening performances under various phase differences are compared
and finally best dimensions for SSB are examined.
Damage Evolution of Laminated Composites Using Continuum Damage Mechanics Incorporate with Interface Element
Authors: Mohammadi Bijan , Hosseini-Toudeshky Hossein , Sadr-Lahidjani Mohammad Homayoun
Published: March 2009

In this paper, 3D continuum damage mechanics (CDM) incorporated with layer-wise theory and
interface element is employed to investigate the progressive damage inside and between the
laminate's layers under quasi-static axial loading. For this purpose, a finite element program is
developed. To simulate the delamination, a quadratic interface element is used which is compatible
with the 8-node numerical layers of layer-wise theory. Matrix cracking and delamination initiation
and propagation of [302/-302]s angle-ply laminate are investigated and the obtained results are
compared with the available experimental evidence.
On Fracture Mechanics Testing Technique Based on Compliance of Specimens
Authors: Cai Li Xun , Jin Lei , Bao Chen
Published: March 2009

Based on compliance testing of a straight-notch compact tensile (SN-CT) or a single edge
bending (SEB) specimen, this paper present a formula with increment form to calculate plastic part of
J-integral, two formulas for a SN-CT specimen and a SEB specimen to transform crack mouth
opening displacement (CMOD) v0 to the crack opening displacement (COD) q along load line, and
simplified formulas to estimate crack length a and effective young’s modulus E. Furthermore, the
relation between v and q of the SN-CT specimens of 45 steel and SEB specimens of 30Cr steel were
investigated. The results show that the formulas to describe the relation between the ratio v/q and the
dimensionless crack length a/w of the specimens accord with the testing results better.
Atomic Simulation of Effect of Stacking Fault and Dislocation on Fracture Behavior in Fe Crystal
Authors: Lu Cheng , Gao Yuan , Zhu Hong Tao , Tieu A. Kiet
Published: March 2009

The defects in crystalline materials significantly affect the fracture behaviors. In this paper
molecular dynamics (MD) model using a potential of embedded atom method (EAM) has been
developed to investigate the effect of the major crystalline defects, stacking fault and edge dislocation,
on the crack propagation in Fe crystal. Six cases with different locations of stacking fault and edge
dislocation have been studied. The strain distribution in lattice aggregate was heterogeneous. The
dislocations were observed slipping along directions [100] and [-100] on the plane (100). Simulation
results showed that the location of the stacking fault and edge dislocation significantly influenced the
crack propagation speed.
Mathematical Model for Compressive Stress-Strain Curve of Recycled Aggregate Concrete
Authors: Wang Wei , Yang Li Jun , Wang Xiao Ni
Published: March 2009

For the effective utilization of recycled aggregate concrete (RAC), it is necessary to
correctly describe its compressive stress-strain curve (SSC) in theoretical and numerical analysis as
well as engineering design of RAC structures. The objective of this study is to establish a good
mathematical model for SSC of RAC. Based on energy dissipation theory, the differential governing
equation of SSC is deduced and a new mathematical model is obtained. The new model can well
describe both hardening type SSC and softening type SSC. It can overcome the shortcoming of the
traditional model. Finally, good agreements have been found between the new model and the
experimental investigations.
Equivalent Stress Intensity Factor of Pre-Northridge Connections
Authors: Ding Lin , Liu Hong Bo , Shao Yong Song , Zhai Chang Hai
Published: March 2009

The objective was to quantify the variation of stress intensity factor to weld root flaw sizes
in steel frame connections. Finite-element analyses were used to study fracture toughness in welded
beam-column connections. Investigations of fracture behavior mainly focused on the standard
pre-Northridge connection geometry. Finite element analysis was performed using the ANSYS
computer program. Stress intensity factor was calculated through a J-integral approach. The
parametric study was conducted to quantify elastic fracture demands as a function of beam
geometries. Results show that stress intensity factor is not uniform and is the largest in the middle
of beam flange. The breadth of beam flange has primary effect on ratio of equivalent stress intensity
factors to average. The ratio is nearly linear with the increase of the breadth, and it increases with the
increase of breadth of beam flange.
The Thermoelectromechanical J-Integral and the Thermal Permeability of Cracks
Authors: Ricoeur Andreas , Kuna Meinhard
Published: March 2009

The J-integral for cracks in structures storing elastic, dielectric and thermal energies
is derived from thermodynamical fundamentals. The FEM is applied to solve thermoelectrome-
chanical boundary value problems, accounting for piezoelectric coupling, thermoelasticity and
the pyroelectric effect. Examples demonstrate the influence of the thermal conductivity of cracks
on the loading of the crack tip.
Creep Curve Modeling to Generate the Isochronous Stress-Strain Curve of Type 316LN Stainless Steel
Authors: Yin Song Nan , Kim Woo Gon , Jung Ik Hee , Kim Yong Wan , Kim Seon Jin
Published: March 2009

An isochronous stress-strain curve (ISSC) needs to be generated for a creep design
application for high-temperature materials. To generate the ISSC for type 316LN stainless steel
(SS), a series of creep data, which was obtained from creep tests with different stress levels at
600oC, was used. Creep curves were modeled by means of a nonlinear least square fitting
(NLSF) of the Garofalo model. In the fitting of the creep curve, a secondary creep region was
separated into first and second phases, and its fitting range was suitable to use for the first
phase. The Garofalo model revealed a good agreement with the experimental creep data, and
its parameters, P1, P2 and P3 revealed a good linear relationship as a function of a stress. The
ISSCs for type 316LN SS at 600oC were successfully generated up to 300,000 hours.
Effects of Equal Channel Angular Pressing and Heat Treatment on Low Cycle Fatigue Properties of 6005 Al Alloy
Authors: Kim W.H. , Cho H.H. , Cha J.H. , Kwun S.I. , Shin Dong Hyuk
Published: March 2009

The effects of equal channel angular pressing (ECAP) and subsequent heat treatment on the
low cycle fatigue properties of 6005 Al alloy were investigated. The ECAPed specimens showed
cyclic softening, whereas the peak aged specimens showed cyclic hardening at all strain amplitudes.
After ECAP, artificial aging was performed at 175°C to observe the change of the low cycle fatigue
properties due to precipitation. The fatigue life and behavior of the unECAPed and ECAPed 6005 Al
alloys were discussed in terms of the microstructural changes and aging conditions.
Influence of Rolling Reduction on Fatigue Behaviour of AA6016/FeP06 Material Compound
Authors: Lamik Abdelrhani , Leitner Heinz , Eichlseder Wilfried
Published: March 2009

The goal of this research project is the development of a simulation model for lifetime
estimation of components manufactured from the AA6016-T4/FeP06 material compound.
Components composed of this material are manufactured predominantly by rolling and deepdrawing.
For this reason, the influence of the plastic deformations during the manufacturing process
on the fatigue behaviour must be investigated. Particularly the cyclic hardening behaviour of FeP06
steel has a relevant effect on the fatigue life of this aluminium-steel compound. Simulation models
for fatigue life estimation therefore have to consider the influence of this hardening effect, which
occurs during the manufacturing process. In this work, test results and a simulation model to take
into account the influence of the rolling reduction on the fatigue behaviour of components
manufactured from the AA6016/FeP06 material compound are presented.
Nondestructive Estimation of Fracture Toughness Using Instrumented Indentation Technique
Authors: Lee Kyung Woo , Kim Hyun Uk , Park Sang Wook , Lee Jung Suk , Kim Kwang Ho , Kwon Dong Il
Published: March 2009

This study focused on the determination of fracture toughness by instrumented
indentation technique. A theoretical model to estimate the fracture toughness of ductile materials is
proposed and used to verify those results. Modeling of IIT to evaluate fracture toughness is based on
two main ideas; the energy input up to characteristic fracture initiation point during indentation was
correlated with material’s resistance to crack initiation and growth, and this characteristic fracture
initiation point was determined by concepts of continuum damage mechanics. The estimated fracture
toughness values obtained from the indentation technique showed good agreement with those from
conventional fracture toughness tests based on CTOD. In addition, we confirmed that the proposed
model can be also applied in the brittle material through modification of void volume fraction.
Sintering and Dielectric Properties of Ba(Mg1/3Ta2/3)O3 Particle Prepared by Spray Pyrolysis
Authors: Yamada Hiroki , Okawa Takashi , Ogihara Takashi
Published: March 2009

Ba(Mg1/3Ta2/3)O3 (BMT) powders were successfully prepared by ultrasonic spray pyrolysis from an aqueous solution of Ba, Mg and Ta. The particles characteristics of BMT nano-sized powders were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD). As-prepared powder particles had a sub-micrometer size with a narrow distribution. Transmission electron microscopy (TEM) observation revealed that the average size of the BMT nano-particles was around 20 nm, and that these particles were aggregated. The dielectric constant (r) of 23.2 and the Q・f of 98,300 were obtained at 1550°C by a spray pyrolysis.
Microstructures and Microwave Dielectric Properties on Annealed Al2O3-TiO2 Composite Ceramics
Authors: Miyauchi Yasuharu , Kagomiya Isao , Shimizu Yukihiro , Ohsato Hitoshi
Published: March 2009

The large negative temperature coefficient of resonant frequency ( τ f ) of Al2O3 is a problem for applicable microwave/millimeter wave dielectrics. A Previous study reported that the τ f was improved by sintering with TiO2 and then annealing, where the annealing decompose the secondary phase of Al2TiO5. This study investigated the hold time of annealing. The Quality factor (Qf ) value decreased when the sample was annealed at 1100°C for 2hrs. While Al2TiO5 was not detected by X-ray powder diffraction, it was located around TiO2 by scanning transmission electron microscopy equipped with energy dispersive X-ray spectroscopy. It should be considered that the degradation of the Qf was caused by the existence of noncrystalline Al2TiO5 and new boundaries between noncrystalline Al2TiO5 and TiO2.
Coolant Effects on Tool Wear in Machining Single-Crystal Silicon with Diamond Tools
Authors: Ohta Tsutomu , Yan Ji Wang , Kodera Sunao , Yajima Shuuma , Horikawa Naoyuki , Takahashi Youichi , Kuriyagawa Tsunemoto
Published: March 2009

The service life of a diamond tool in cutting single-crystal silicon is normally very short because of severe tool wear. Therefore, it is important to use a proper coolant in order to restrain tool wear. In this paper, the performances of oil-based and water-based coolants were compared in silicon machining by investigating cutting forces and tool wear geometries. The water-based coolant was found to restrain flank wear more effectively than the oil-based one. The effective tool life using the water-based one was averagely three times longer than that using the oil-based one. The tool wear mechanism might be related to microplasma generated between silicon and diamond during cutting.
Spatial Distribution of Cooling Mist for Precision Grinding
Authors: Gao Y. , Xin J. , Lai H.
Published: March 2009

In order to enhance the cooling performance, better understanding of the effects of coolant parameters is necessary. In this project, a total of five input parameters for actively cooled and activated cutting fluid were studied. An aerosol spectrometer was used to measure the particle size spatial distribution of the cooling mist in the fluid. Taguchi method was used in the design of experiments. It was found that the unit volume net specific particle counts exhibit the behavior of oscillation and attenuation of a second order dynamic system. Cooling mist particle spatial frequency ranges from 0.01269/μm to 2.5/μm, the weighted average size ranges from 0.3051μm to 3.714μm and the particle size difference for 99.8% count attenuation ranges from 0.5μm to 19.7μm. The order of importance of the input parameters was studied and the coolant concentration was found as the most important input parameter for the unit volume net particle counts.
Characteristics of the Wheel Surface Topography in Ultra-precision Grinding of Silicon Wafers
Authors: Huo Feng Wei , Guo Dong Ming , Kang Ren Ke , Jin Zhu Ji
Published: March 2009

A 3D profiler based on scanning white light interferometry with a lateral sampling interval
of 0.11μm was introduced to measure the surface topography of a #3000 diamond grinding wheel,
and a large sampling area could be achieved by its stitching capability without compromising its
lateral or vertical resolution. The protrusion height distribution of diamond grains and the static
effective grain density of the grinding wheel were derived, and the wheel chatter and the deformation
of the wheel were analyzed as well. The study shows that the grain protrusion height obeys an
approximate normal distribution, the static effective grain density is much lower than the theoretical
density, and only a small number of diamond grains are effective in the grinding process with fine
diamond grinding wheel. There exists waviness on the grinding wheel surface parallel with the wheel
cutting direction. The cutting surface of the grinding wheel is not flat but umbilicate, which indicates
that the elastic deformation at the wheel edges is much larger than in the center region.
Thermal Deformation of Base Sheet and Local Deformation Around Laser Cutting Edge
Authors: Nunobiki Masayuki , Okuda Koichi , Morino Shogo
Published: March 2009

When many products were cut out from a wide base sheet by laser cutting in some
conditions, an error occurred in a height regulator by the sheet's greatly bending. It is necessary to
avoid occurring the error at unmanned processing. We paper investigated local deformation around
cutting edge. The cutting path consists of piercing point, terminal point, straight lines, cranks and
curves. We measured local deformation around terminal point, crank and straight line. It was clarified
that base sheet bent greatly around terminal points and crank and the sheet curved gradually along the
straight line. We investigated relationship between global deformation of the base sheet and the local
deformation. It was able to presume the entire deformation of base sheet by overlapping the individual
deformations around cutting edge.
Fractal Analysis of Self-Sharpening Phenomenon in cBN Grinding
Authors: Ichida Yoshio , Sato Ryunosuke , Fujimoto Masakazu , Fredj Nabil Ben
Published: March 2009

This paper presents a fractal analysis of the self-sharpening phenomenon of the grain cutting edges in cBN grinding. To clarify the self-sharpening mechanism due to the micro fracture of the cutting edges, the changes in three-dimensional profile of the cutting edges in the grinding process have been measured using a scanning electron microscope with four electron probes and evaluated on the basis of the fractal analysis. The fractal dimension for surface profile of the cutting edge formed by the micro fracture is higher than that of the cutting edge formed by the ductile attritious wear. Therefore, the complicated changes in shape of the cutting edge due to the self-sharpening can be evaluated quantitatively using the fractal dimension.
Subsurface Structures of Monocrystalline Silicon Generated by Nanogrinding
Authors: Huang Han , Wu Y.Q. , Wang Y. , Zou Jin , Zhou Li Bo
Published: March 2009

This paper reports the effect of nanogrinding conditions on the formation of subsurface structures of monocrystalline silicon (100) substrates. It was found that the amorphization and the transformation of high pressure phases were related to the grit depth of cut employed in nanogrinding. The formation mechanisms were found to be different from those previously reported from the nanoindentation studies.
Research on Dynamic Performance of Milling System for Parallel Indexing Cam Contour Milling
Authors: Guo Pei Quan , Wang Shou Ren , Shi Jin Ping , Fan N. , Wang W.
Published: March 2009

Cutting force model for flat end milling and dynamic model of cam milling system were
established based on the analysis of machining system for parallel indexing cam contour milling.
Solution for dynamic performance of this kind of milling system has been introduced. A system,
consisting of NC milling machine SK1632K3, tooling and workpiece, has been taken as example to
analyze how cutting speed, feeding, or processing redundancy influence the dynamic performance of
machining system. Furthermore, milling error of cam contour has been evaluated corresponding to
different machining parameters. Simulation and analysis results are very close to practical
manufacturing situation.
CAD Application on Manufacture of Forming Shoulder for Packaging Machines
Authors: Zhou Y.J. , Zhang Qiu Ju
Published: March 2009

Based on the theoretical analysis of forming shoulder used in fill-and-seal packaging
machine, this paper presented the 2-D and 3-D mathematical models of offset bending curve jointing
the vertical tube and shoulder parts. According to the technology widely used in the manufacturers,
the theoretical basis was provided for preparing the rough parts to make the shoulders. Furthermore, a
new method using test tube was proposed to check the shape curve and locate the shoulder parts
before welding. Transformed from 3-D offset bending curve, the 2-D cutting data of test tube was
also provided for practical use.
Research of Automated Process Planning Based on 3D Feature Component Model
Authors: Qin Hui Bin , Wu Shu Fang , Hou Z.L. , Wang Zong Yan
Published: March 2009

This paper analyzed the current process planning based on 3D feature model, and pointed
out the exiting disadvantages. The framework and key technologies that play a vital role in process
planning were issued. A uniform manufacturing model, which was built on component model by
offsetting surface features and volumetric features. It implemented the typical machining features
recognition and extraction, including visional entity and conceal technological attribute. It also set
up hierarchy planning model. Under the support of these theories, a feature-oriented process
planning generation system based on Solidworks CAD platform was developed. With the testing
work on the interrelated examples, the software system has validated the feasibility and
practicability of the method in this paper, which will enrich the way to make stock model in existent
CAM software system. It has significant meaning to promote the integration of CAD/CAPP.
A Hybrid Genetic Algorithm for Hybrid Flow Shop Scheduling with Load Balancing
Authors: Zhan Yong , Qiu Chang Hua , Xue Kai
Published: March 2009

This paper considers the practical manufacturing environment of the hybrid flow shop (HFS) with non-identical machines in parallel. In order to significantly enhance the performance level of manufacturing, maintaining load balancing among parallel machines is very important. The aim of this paper is to minimize makespan with load balancing in a non-identical parallel machine environment by using hybrid genetic algorithm (HGA). In the HGA, the neighborhood search-based method is used together with genetic algorithm as local optimization method to balance the exploration and exploitation abilities. The representation of chromosome used in this paper is composed of two layers: allocation layer and sequencing layer, which can be encode and decoded easily. In generating initial population, a special constraint of load balancing between parallel machines is used to reduce the number of individuals. And particular crossover operation is used, which generates multiple offspring at a time, so that the efficiency of the algorithm can be well improved. At last, the proposed algorithm is tested on a benchmark, and numerical example shows good result.
Design of Key Parameters on Differential Velocity Vane Pump of Eccentric-Noncircular Gears
Authors: Hu M. , Chen M.
Published: March 2009

The parameters of impellers and the pump housing as key assembly to differential velocity vane pump of eccentric-noncircular gears has been designed in this paper. By researching vane spacing angles, vane numbers, vane angle and maximal opening angle on impellers, the results are gained that vane spacing angles are the periodic function of noncircular gear angular velocity, vane numbers is identical with centrodes vane numbers of noncircular gear. Assuring right and reliable working to the impellers, numbers, positions and opening angles of the matching holes of the pump housing are analyzed; defining that actual impeller vane angle must be less-than theoretical value, numbers of the matching holes must be vane numbers and opening angles of the matching holes must be less-than theoretical value, which provide the condition for concrete structure design for differential velocity vane pump of eccentric-noncircular gears.
Theoretical Research on Polishing Free-Form Surface with Magnetic Abrasive Finishing
Authors: Zhang Man Dong , Lv Ming , Chen H.L.
Published: March 2009

In the paper, polishing free-form surfaces of die are studied with magnetic abrasive
finishing. The principle of magnetic abrasive finishing free-form surface, the design of magnetic
pole, the composition and categories of magnetic abrasive are introduced. Through digitizing of
free-form surface by using trimmed NURBS, based on residual roughness, machining accuracy and
other parameters, the offset variable of free-form surface, which is the path of magnetic pole, is
derived with the computer aided geometric design theory. These will provide theoretic foundation
for the realization of finishing free-form surfaces of die automatically.
Development on CAD Software about Slewing Bearing
Authors: Yu X.L. , Meng C.S. , Liu L.P. , Cao G.L.
Published: March 2009

Based on the analyzing the fact of slewing bearing production, the primary need for
software of the corporation is determined. On this condition, it has discussed the main designs,
which include the framework of software, key categories, and design of method and so on. Some
examples are given. Through using this software, we can not only reduce the workload of design of
nonstandard slewing bearing which is repeating and heavy, but also avoid misplay of the designer.
This software also provides the precondition for Computer-Aided Process Planning (CAPP).
Through the using of the software, we can increase the rate of eligible product, reduce the cost of
production and fulfill time limit for client better.
Performance Analysis on Capacitance Micromechanical Comb-Finger Accelerometer
Authors: Hu Xue Mei , Han Q.L.
Published: March 2009

Variable-capacitance micromechanical accelerometer is widely used because of its high
sensitivity and low power. Therefore, the further study on its performance has much theoretical and
applicable significance. This paper takes the closed-loop bias stationary comb-finger
variable-capacitance accelerometer as an example, introduces its operation principle, establishes its
mechanics model through analysis, and gives force balance equations. Then it researches and
analyzes its performances such as electrostatic forces, full scale, stability, resolution and so on. Based
on the model of the parameters from the accelerometer, key expressions were acquired. These
expressions reflect and affect electrostatic forces, measure range, stability, sensitivity of the
accelerometer. The results prove that performance of the accelerometer are connected with the
dimension of the beam, the mass, the area of the pole plate, bias voltage, feedback voltage and so on.
This work will provide a reliable theoretic foundation for the further optimum design of
variable-capacitance micromechanical accelerometer.
Design and Study on Power Supply for Giant Magnetostrictive Accurate-Motion Actuator
Authors: Wu M. , Zhu Xi Lin
Published: March 2009

The architecture and operation theory of Giant Magnetostrictive Accurate-motion Actuator have been introduced. After analysing the driving characteristic of giant magnetostrictive material and requirement of driving power, a design method of wide range and high precision NC constant-current source has been put out. The output circuit is composed of serial 12-bit DACs Max531, low-noise high-speed precision operational amplifiers OP27 and driving circuit. It provides current from 0 to 2.048A with 0.5mA step value. Two fully differential input channels 16-bit, sigma-delta ADCs AD7705 collects output current in feedback loop. Current ripple is controlled under 0.25mA through using homemade high-performance linear power. The result shows that the driving power with characteristic of high stability and fast response meets the needs of driving of Giant Magnetostrictive Accurate-motion.
Finite Element Modelling and Analysis of Cutting-Direction Burr Formation
Authors: Wang Xiao , Yan H. , Liang C. , Wu B. , Liu Hui Xia , Cai Lan
Published: March 2009

To prevent or reduce the formation of burr efficiently in metal cutting, it is necessary to reveal the burr formation mechanism. A finite element model of cutting-direction burr formation in orthogonal machining was presented in this paper. The simulation of the burr formation process was conducted. Undeformed chip thickness, rake angle, rounded cutting edge radius and workpiece material were included in cutting conditions, whose influences on burr formation were investigated, according to the simulation results. By comparing the results of the simulation and the experiment, good consistency is achieved which proves that the finite element model of burr formation in this paper is significant and effective to predict burr formation.
Thermal Imaging Experimental Research on Temperature Field for Milling Insert
Authors: Zhang Yu Hua , Tan Guang Yu , Liu Guang Jun
Published: March 2009

During the process of interrupted cutting, milling insert suffers from periodic thermal
shock. The bad temperature field caused by cutting heat is the direct reason for tool failure. In order
to get more accurate temperature field distribution of milling insert, the experimental research on
temperature field is carried on with the FLIR infrared thermal imager. This paper takes hard cutting
material 3Cr1Mo1/4V as example. Through the contrast experiments, the temperature field
distribution of tool-chip contact area is gained at the moment of milling insert going into or out
from the workpiece, and also the difference of failure modes among different milling inserts is
revealed. The experimental analysis results show that more accurate distribution of temperature
field will be obtained when we apply the infrared thermal imager to observe temperature field
during interrupted cutting process. Optimization design for groove of milling insert also can be
based on those results.
The Study of Ignition Parameters for Energy Efficient Processing of High Temperature Non-Oxide Ceramics by the Micropyretic Synthesis Route
Authors: Li H.P.
Published: March 2009

The influence of ignition parameters for energy efficient processing of high temperature non-oxide ceramics by the micropyretic synthesis route is studied numerically in this article. The simulation results show that a lower ignition power leads to longer ignition time to initiate reactions. An increase in the ignition time also increases the length of pre-heating zone before propagating, which further changes the initiate propagation velocity and oscillatory frequency of the temperature variations. Such changes in the initiate propagation velocity and temperature variations result in inhomogeneous structures at the ignition spot. The simulation also indicates that using a higher power to ignite the micropyretic reactions can lower the ignition time and further prevent the inhomogeneous structures from being formed at the ignition spot. However, more heat loss is noted to occur due to a high temperature gradient and the energy required to ignite the reaction. The numerical calculation indicates that there is a 20 % increase in the required energy and a 90% decrease in the required time to ignite the specimen when the ignition power is increased from 87.5 kJ/(g･s) to 962.5 kJ/(g ･s). In addition, the effect of the individual material property on ignition is also investigated.
Effect of Ductile and Brittle Phases on Deformation and Fracture Behaviour of Molybdenum and Niobium Silicide Based Composites
Authors: Mitra R. , Chattopadhyay K. , Srivastava Arvind K. , Ray Kalyan Kumar , Eswara Prasad N.
Published: March 2009

A comparative study on the microstructure-mechanical property relationships in the molybdenum and niobium silicide based composites has been carried out with emphasis on the role of the ductile and brittle phase constituents at ambient and elevated temperatures. The MoSi2, MoSi2-20 vol.% SiC and -Mo-Mo3Si-Mo5SiB2 composites have been prepared by powder metallurgy processing. Furthermore, the niobium silicide based composites, having a eutectic of Nb solid solution (Nbss) and (Nb,Mo)5Si3, and either Nbss or (Nb,Mo)5Si3 as the primary phase in the hypoeutectic or hypereutectic compositions, respectively, have been processed by arc melting. The increase in fracture toughness with respect to that of MoSi2 is modest in the MoSi2-SiC composites, and more significant in the multiphase Mo-Mo3Si-Mo5SiB2 and Nbss-(Nb,Mo)5Si3 based in-situ composites with ductile reinforcements. The ductile phase, either Mo or Nbss aids in toughening chiefly through crack arrest and bridging, and undergoes plastic yielding under constraint during deformation, leading to a higher energy of fracture. In the MoSi2 and MoSi2-SiC composites, the matrix grain size has a significant role in high temperature strength retention and strain hardening behaviour. In the ductile phase reinforced composites, the hard silicide-based intermetallic phases contribute to elevated temperature strength, while the constrained plastic deformation of the -Mo or Nbss is responsible for much higher rate of strain hardening than in the MoSi2 and MoSi2-SiC composites.
Development of High Temperature TiB2-Based Ceramics
Authors: Raju G.B. , Basu B.
Published: March 2009

In view of potentiality of titanium diboride (TiB2) materials for high temperature applications, this paper presents the state of art on the processing, microstructure and properties of TiB2 ceramics. TiB2 ceramics are of interest for applications such as cutting tools, wear resistant parts, armor material and electrode materials in metal smelting because of their excellent combination of properties including high hardness, elastic modulus, better strength to weight ratio, wear resistance, good thermal and electrical conductivity. However, such broader applications of the monolithic TiB2 are inhibited by factors like high sintering temperature and poor toughness. Hence, research efforts are directed towards processing TiB2 at lower sintering temperature as well as to enhance the properties with the use of various metallic and non-metallic sinter-additives. In the above perspective, we review the existing literature in this article. In addition, our recent research results obtained with TiB2-TiSi2 materials are also presented. A review of research results revealed that a combination of room temperature properties, i.e. maximum Vickers hardness of 31 GPa and indentation toughness of 11 MPa m1/2 and flexural strength of 810 MPa is obtainable with optimally sintered TiB2. More importantly, a maximum hardness of 9 GPa (at 900oC) and flexural strength of 471 MPa can be retained upto 1200oC. From the perspective of oxidation resistance, TiB2 samples exhibit parabolic oxidation kinetics below 1000oC as result of the formation of TiO2 (s), and B2O3 (l) and linear oxidation kinetics above 1000oC in the presence of crystalline TiO2 and volatile B2O3.
Macrophage Induced Effect of Particulate Silica on Rat Mesenchymal Stem Cells In Vitro
Authors: Wilson Timothy , Viitala Reeta , Puska Mervi , Jokinen Mika , Penttinen Risto
Published: March 2009

The role of silica and macrophages in fibrosis is well documented, but in bone formation it is relatively unknown despite decades of research with bioactive glasses. In this study macrophages were isolated from rat peritoneal and then cultured for five days in the presence of two types of silica microparticles with different solubilities. After the fifth day the culture medium was collected, purified and used as an additive in bone marrow derived rat stem cell cultures. The stem cells were cultured for five days in α-mem containing only 0,5% of FCS, enabling cell survival but disrupting their proliferation. As controls, stem cells were also cultured in α-mem containing silica microparticles. At days one and five the amount of soluble collagen was assayed from the culture medium and the cells were counted. All stem cell cultures with macrophage medium additives were found to be proliferative, with statistically significant difference to controls. However, collagen was only produced in cultures containing medium from macrophages cultured with fast-dissolving silica microparticles. This suggests that silica can induce cell proliferation and extra cellular matrix protein secretion which is mediated by macrophages, and that the solubility of silica is also a major factor in this reaction.
Novel Glass-Ceramics for Dental Application by Sol Gel Technique
Authors: Chatzistavrou Xanthippi , Hatzistavrou E. , Kantiranis Nikolaos , Papadopoulou Lambrini , Kontonasaki Eleana , Chrissafis K. , Koidis Petros , Paraskevopoulos Konstantinos M. , Boccaccini Aldo Roberto
Published: March 2009

The aim of this study was the fabrication using a sol-gel technique of a new glass-ceramic with potential use in dental applications. The characterization of the composition and microstructural properties of the produced material confirmed the similarity between the new sol-gel derived glass-ceramic and a commercial leucite based fluorapatite dental glass-ceramic. The produced material has potential application in dental restorations and it is expected to exhibit better control of composition, microstructure and properties due to the intrinsic advantages of the sol-gel preparation method.
Calcium Phosphate Formation on Ethylphosphoester of Poly(ε-Caprolactone) and Poly[Bis(Methacrylate)]Phosphazene In Vitro
Authors: Puska Mervi , Rodrigues Silva Nykänen Virgínia , Korventausta Joni , Nykänen Antti , Närhi Timo , Ruokolainen Janne , Seppälä Jukka
Published: March 2009

Phosphorus containing biopolymers have been synthesized and studied as polymeric candidates for potential tissue engineering applications. The presence of phosphorus in the polymeric structure may improve the biocompatibility of polymers by enhancing their tissue contact. One aim of this study was to examine the chain extending reaction of poly(ε-caprolactone), PCL, using ethyldichlorophosphate as a coupling agent. A preliminary survey was done to find out whether the presence of phosphoester units in a rapidly degradable polymeric structure improves the Ca phosphate formation on PCL. Another aim of this study was to synthesize one kind of polyphosphazene, i.e. poly[bis(methacrylate)]phosphazene, PMAP. In addition, a preliminary biomineralization study for PMAP polymer was carried out. The results of the biomineralization studies indicated some bioactivity of both biopolymers.
In Vitro and In Vivo Behaviour of a Ceramic with Interconnected Macroporosity
Authors: Bernstein Anke , Gildenhaar Renate , Berger Georg , Mayr Hermann O.
Published: March 2009

Bioactive ceramics such as β-tricalcium phosphate (β-TCP) promote and enhance biological fixation. Ceramics with a porous interconnected structure are suited for facilitation of bony ingrowth. An interconnected pore system with pore diameters in excess of 100 µm is required for cell penetration, tissue ingrowth, vascularization and nutrient delivery to the centre of the regenerating tissue. Human osteoblasts were cultured on the surface of a ceramic. In an in-vivo study, β-TCP samples with a porous interconnected structure were implanted into the femur of sheep and then investigated 6 weeks after operation. Histological analysis was performed on the area surrounding the implant. An indentation test was performed to complete failure of the bone/ceramic compound. Linear load, peak load and stiffness were recorded. All cylinders were found to be biocompatible and osteoconductive. Bone was more abundant in the outer ring than in the rest of the cylinder. The ceramic/bone compound was of low mechanical grade.
Behaviour of Calcium Alkali Orthophosphate Cements under Simulated Implantation Conditions
Authors: Jörn Daniela , Gildenhaar Renate , Berger Georg , Stiller Michael , Knabe Christine
Published: March 2009

The setting behaviour, the compressive strength and the porosity of four calcium alkali orthophosphate cements were examined under laboratory conditions (dry) and under conditions similar to those during clinical application (37°C, contact with body fluid). The results showed an increase of the setting times when specimens were covered with simulated body fluid. Especially, the final setting time (FHZ) was significantly higher for three of the four cements. Furthermore, when specimens were stored in SBF for 16h, an extensive decrease of the compressive strength was noted. The porosity was more than twice as high after 16h in SBF and this may be the cause for the great decrease of the compressive strength.
Rietveld Refinement of Sintered Magnesium Substituted Calcium Apatite
Authors: Sader Marcia S. , Moreira Elizabeth L. , Moraes Valéria C.A. , Araújo Jorge C. , LeGeros Racquel Z. , de Almeida Soares Gloria Dulce
Published: March 2009

The incorporation of magnesium in the synthetic apatite has been associated with biomineralization process and osteoporosis therapy in human and animals. Magnesium easily replaces calcium in the apatite lattice and influences or controls the hydroxyapatite crystallization processes. In this work, Mg-substituted calcium deficient apatite, with Mg/Ca ratio = 0.1, 0.15 and 0.2 were synthesized by precipitation method. Then, sintered at 1000 oC and compared with a commercial product labeled as tricalcium phosphate sintered at the 1000 oC. The sintered products showed tricalcium phosphate (β-TCP) structure. The Mg2+ substitution in the Ca(4) and Ca(5) sites of β-TCP and the lattice parameter changes were estimated using the Rietveld method. Using this method, the formulas Ca2.73(Mg0.27)(PO4)2, Ca2.71(Mg0.29)(PO4)2 and Ca2.70(Mg0.23Mg0.07)(PO4)2 were calculated for the samples with Mg/Ca ratio = 0.1, 0.15 and 0.2 respectively.
Antibacterial Titanium/Calcium Phosphate Implant Surfaces
Authors: Prinz Cornelia , Neumann Hans Georg
Published: March 2009

The antibacterial effects of titanium oxide/calcium phosphate and calcium phos-phate/copper phosphate composite coatings have been investigated. Implant-like rough blasted tita-nium substrates are covered by a native titanium oxide layer. Together with the electrodeposited calcium phosphate layer a clear antibacterial effect has been observed. Electrodeposited calcium phosphate coatings were also dipped in aqueous copper sulphate solutions to convert partly calcium phosphate to copper phosphate. The antibacterial properties of such coatings can be controlled and adjusted to the clinical setting and to specific indications. Patient-tailored antibacterial treatments seem to be possible and may be of special interest for high-risk operations.
Pre-Clinical Analysis of an Acetabular Cup with Improved In Vivo Stability and Integrity
Authors: Dickinson Alex , Browne M. , Jeffers Jonathan , Taylor Andy
Published: March 2009

In recent years, the processing of porous ceramic materials for implant applications has motivated the development and optimization of new technologies. To this purpose, a globular protein based (i.e. ovalbumin) consolidation approach has been proposed. In the present study, a porous hydroxyapatite:b-tricalcium phosphate - biphasic ceramics (BCP), was processed by consolidation using the protein-action technique. The processed ceramic materials exhibited appropriate pore configuration in terms of size, morphology and distribution. The in vitro reactivity and dissolution behavior of the ceramics was evaluated in SBF and biocompatibility in an osteoblasts culture, respectively. Overall, the materials tested showed biocompatibility and suitable properties for osteoconduction. A rough surface pattern displayed by the ceramics seemed to have improved both; cell adhesion and proliferation processes. In conclusion, this study revealed that the porous matrices obtained, promoted suitable development of cell metabolism without cellular death.
TTCP-DCPA Based Calcium Phosphate Cements Containing Hybrid Microparticles as Drug Carriers
Authors: Romeo Hernán E. , Fanovich María A.
Published: March 2009

In recent years, considerable attention has been focused on the development of new composite materials for application as drug delivery systems. In this field, calcium phosphate cements (CPCs) are often employed as support to delivery of drugs, but their behavior has some drawback related to the so-called burst effect. The aim of this work was to develop new CPCs formulations from synthesized tetracalcium phosphate (TTCP), dicalcium phosphate anhydrous TTCP and drug-containing hybrid microparticles (DCHM). The main function of these DCHM is providing nuclei of high concentration of drugs into the CPCs. The DCHM were synthesized via the sol-gel method from a bridged precursor of the type (H3CO)3 – Bridge – (OCH3)3 and aspirin (AS) as model drug. The inorganic polycondensation reached 89.5 % as calculated by 29Si NMR. The analysis by small angle X-ray scattering (SAXS) reveled a short range structural ordering in the DCHM at molecular level. Effective incorporation of AS inside the microspheres was detected by FTIR spectroscopy. In vitro tests of DCHM according to ISO 10993-5 revealed non-cytotoxic behavior. Four CPCs formulations containing 0, 1, 5 and 10 wt % of DCHM, were evaluated. The presence of DCHM did not modify neither the degree of conversion to low-crystallinity HA nor the measured setting times of the CPCs, however, the amount of incorporated microparticles considerably affected the degree of porosity (macropores of 200 µm) and interconnectivity of the cement matrix.
Morphological Characterization of 3D Porous Scaffolds Based on Portland Cement
Authors: Mansur Alexandra A.P. , Mansur Herman S.
Published: March 2009

There is a constant need for bone substitutes. This work was focused on evaluating morphological characteristics of new bioceramic three-dimensional scaffold for bone tissue engineering based on Portland cement with air-voids introduced by outgassing reaction product from lime and aluminum powder. Pores morphology was observed using scanning electron microscopy (SEM). Bulk density, apparent density, and apparent porosity were measured by Archimedes method. Water absorption by total immersion and by capillarity was also investigated. The results have indicated that cement based scaffolds exhibit a hierarchical structure with interconnected macropores and a micropores framework that indicate potential use of the developed porous materials as bone substitutes.
The Lateral Buckling of Steel-Concrete Composite П-Beam
Authors: Jiang Li Zhong , Sun Lin Lin , Li Xing
Published: March 2009

Based on the theoretical analysis of steel-concrete composite П-beam’s lateral buckling, the computing model and simplified computing model on the stability of composite П-beams are brought forward. According to above two models, composite beam’s lateral buckling is studied in negative moment regions using the energy method, and the formulas which are used to calculate critical bending moment in negative moment regions in the elastic stage are deduced. Compared with other stability theories and methods, this paper represents the design correction and suggestion about the stability of composite П-beam in negative bending regions. Moreover, the simplified calculation method, which is used to compute the lateral critical buckling moment of steel-concrete composite П-beam loaded by equal-end moment, not only simplifies the computing process, the computing results also have the equivalent accuracy with numerical computing methods.