bluuebunny/crossref_metadata_2025 huggingface dataset:
Preparation of Ferroelectric BaTiO3 Films by Electrophoretic Deposition Technique
Authors: Ma Ya Lu , Zhang Yu , Zhu Hong Long
Published: March 2009

Barium titanate ferroelectric films on Pt substrates were fabricated by electrophoretic deposition (EPD) technique. The barium titanate films sintered at different temperature (600°C, 900°C, 1050°C, 1150°C, 1200°C) for 2h, which were prepared via repeated EPD-sintering route 2~3 times were sufficiently dense and had uniform microstructure. The XRD pattern and SEM microphotography have been measured in order to investigate the effects of the final annealing temperature on the phase compositions and microstructure of the film. The experiment results showed that barium titanate films were crystallized into the tetragonal phase at 1050°C and above. The room temperature dielectric constant (ε) and loss tangent (tanδ) at 1kHz were respectively determined for different samples sintered at 600°C, 900°C, 1050°C, 1150°C and 1200°C. Both ε and tanδ showed anomaly peaks at 125°C. The results showed that typical BaTiO3 films sintered at 1050°C having higher dielectric constant (ε=2300) and lower dielectric loss (tanδ=0.02). The room temperature remanant polarization (Pr) and coercive field (EC) were found to be 1.9μC/cm2 and 35kV/cm, respectively.
Thermoelectric Properties and Mechanism on Porous Silicon Wafer
Authors: Xu Gui Ying
Published: March 2009

In order to improve conversion efficiency of thermoelectric materials, a designing model
named Combined Model of Dense and Hollow Quantum Structures (CMDHQS) and a concept named
Combined Effect of Dense and Hollow Quantum Structures (CEDHQS) have been proposed. A
proof-of-concept experiment has been carried out for fabrication of porous silicon wafer with CMDHQS
by physical vapor deposition and selective chemical erosion methods. By the investigation on the relation
of microstructure, micro-composition and thermoelectric properties, it is found that porous silicon wafers
with CMDHQS can be obtained by these two methods and have much higher thermoelectric properties
than normal silicon materials, that is 3 times higher than the highest results reported, which make porous
silicon become a candidate as thermoelectric materials.
Synthesis of Mixed Conducting Oxides SrFeCo0.5Oy Powder by Citrate Method
Authors: Xu Zhi Jun , Chu Rui Qing , Cui S.C. , Zhang Jin Son
Published: March 2009

Mixed-conducting ceramic oxide SrFeCo0.5Oy powders were prepared by a citrate method, and
the contributing factors to the formation of homogeneous fine powder with a pure perovskite-type
structure were ascertained. The resulting powder is pure, homogeneous and possesses a reasonably fine
particle size. Attempts were made to understand the synthesis process and it was confirmed that the
method produces powder had greater composition uniformity, lower residual carbonate levels and smaller
particle sizes.
Molecular Dynamic Simulation Study of AFM Single-Wall Carbon Nanotube Tip-Surface Interactions
Authors: Liang Ying Chun , Dou J.H. , Bai Qing Shun
Published: March 2009

Carbon nanotubes (CNTs) represent ideal Atomic Force Microscope (AFM) tip materials due to their remarkable mechanical properties. Dynamic interactions of a Single-wall Carbon nanotube (SWCNT) indenting towards a monocrystalline hydrogen-free Silicon surface (001) are investigated using molecular dynamic simulation. The critical strain and strain force along the axis of the tube from elastic to plastic regimes are calculated. The simulation shows the deform process in elastic regimes is similar to the process of two ends inward compressed. The atoms of nanotube tip adsorption to the Silicon surface has been observed in the plastic regimes. The mechanical microprocess of AFM’s single-wall Carbon nanotube tip and Silicon surface interactions from elastic to plastic regimes can be well comprehended from the view of nanoscale energetic evolution.
Experimental Study on the Surface Modification and Materials Removal of Ultra Thin DLC Films
Authors: Fan Zhen , Kan B. , Ding J.N. , Yang Ping
Published: March 2009

Thin DLC film is in need for higher magnetic storage density. Surface modification and materials removal of DLC films were carried out in order to estimate the reliability of the ultra thin DLC films. Atomic force microscope (AFM) was used to investigate the wear resistance, surface modification and mechanical reliability of the films. Wear test by contact AFM indicated that wear depth under the same load was varied at different thick films. The local modification is studied using conductive atomic force microscope (C-AFM). Especially, topography change is observed when DC bias voltage applied. Experimental results show that the DLC surface is not modified after direct current applied on the tip. While positive voltage is applied on the DLC film surface, the nanoscale pit on the surface is formed clearly. According to the interaction force between CoCr coating MESP tip and the DLC film surface, as well as the Sondheimer oscillation theory, the “scale wing effect” of the pit is explained. Electromechanical coupling on the DLC film indicates that the depth of pit increases with the augment of force applied on surface when normal force is less than a certain threshold pressure.
Nanometer Positioning in the Presence of Friction
Authors: Lu Li Hua , Guo Yong Feng , Tachikawa H. , Liang Ying Chun , Shimokohbe Akira
Published: March 2009

This paper deals with nanometer positioning in the presence of friction. The object
studied is a ball-screw-driven and linear-ball-guide-supported table system. For this system, the
friction dominates the resulting performance for micro-motion and the system exhibits
microdynamic characteristic which is rather different from macrodynamics. Inherently a controller
with high loop-gain is needed to suppress the effect of friction. A PID controller is designed for the
table system for step height smaller than 10μm. Experiment and simulation results indicate that the
PID controller can provide a sufficiently high-loop gain and effect of friction is suppressed. In
point-to-point(PTP) positioning for step heights from 10μm down to 10nm, the positioning error is
within ±2 nm and the response dynamics is satisfactory.
Study to Enhance the Precision of Micro-EDM
Authors: Jia Bao Xian , Zhao Wan Sheng , Wang Zhen Long , Hu Fu Qiang
Published: March 2009

Considering the key technologies to enhance the accuracy of micro-EDM, a micro-EDM
system and some techniques are researched. In this system, a micro-energy pulse power supply
whose open voltage and capacitance can be adjusted is developed. The detection and control
subsystem of the machining process is designed and applied. A simple method of machining high
precision microelectrodes is adopted. The forming mechanism of the gap in EDM process is
analyzed theoretically. The processing experiments are carried out on the system, and the results
basically coincide with the theoretical analysis. The experimental results of machining
microelectrodes and micro holes show that the Ø4.5±0.5μm microelectrodes can be ground, and the
Ø6±2.0μm micro holes can be drilled.
Simulation of Solid-Liquid Two-Phase Flow Inside and Outside the Abrasive Water Jet Nozzle
Authors: Hou Rong Guo , Huang Chuan Zhen , Wang Jun , Lu X.Y. , Feng Yan Xia
Published: March 2009

Simulation of the velocity field of solid-liquid flow inside and outside the abrasive water jet
nozzle was studied by the computational fluid dynamics software(CFD). The velocity field of the
flow in the abrasive water jet (AWJ) nozzle was obtained. The results indicate that the swirl is
produced in the nozzle and the abrasives are all distributed along the inner surface of the nozzle. The
velocity at the center of the outlet face is the highest, while it is smallest at the both edge. The
dispersion of the flow is happened when it flows out of the nozzle, but the flow velocity away from
the outlet at a distance of about 4 times of the outlet diameter changes little. The fillet diameter, the
inner cone angle, the length of mixing tube of the nozzle greatly affect the field of two-phase flow.
The velocity of outlet increases with an increase in the fillet diameter, the flow becomes ease when
the cone angle decreases, the mixing tube hampers the two-phase flowing.
A Simple Detachment Method for Fabricating a Polymer Nanotemplate Structure
Authors: Kim J.K. , Park J.W. , Suh K.Y.
Published: March 2009

In this report, nanopatterns consisting of an organic polymer film were fabricated using a simple detachment method. The method used a patterned ultraviolet (UV) curable poly(urethane acrylate) (PUA) as a mold and an organic polymer layer as a template material. A thin film was prepared by spin coating and then annealed below the glass transient temperature while in physical contact with the PUA mold. The polymer layer in contact with the mold was detached due to the difference in adhesion force, resulting in a well-defined nanoarray of the polymer template. Nanopatterns as small as 70 nm lines were fabricated using this approach.
Numerical Modelling of Soft Soil Installed by PVDs
Authors: Yu X.J. , Fang Zhen , Yin Jian Hua , Wang Shan Yong , Yan Yun
Published: March 2009

One small-scale physical model test on the PVD (Prefabricated Vertical Drain) treated
Hong Kong marine clay was simulated using finite element method (FEM) in this study. A User
MATerial (UMAT) subroutine describing an Elastic Visco-Plastic (EVP) constitutive model was
developed and incorporated into one commercial finite element code ABAQUS. A degressive
permeability of the PVD strip was included to consider variations of its permeability during the
consolidation process. The UMAT and the adopted reducing technique were demonstrated to be
effective by good agreement between the observed consolidation settlement and excess pore water
pressures and the simulated ones.
A Finite Element Analysis of the Thermo-Hydro-Mechanically Coupled Problem of a Cohesive Deposit Using a Thermo-Elasto-Viscoplastic Model
Authors: Kimoto Sayuri , Oka Fusao , Kim Young Seok , Takada Naoaki , Higo Yosuke
Published: March 2009

We propose a thermo-hydro-mechanically coupled finite element analysis method for
clay with a thermo-elasto-viscoplastic model. The volume changes in soil particles and pore fluids are
introduced into the analysis method. The instability of the problem is studied and a numerical
simulation of the thermal consolidation is presented using the newly developed analysis method. It
was confirmed that the analysis method can reproduce the thermal consolidation phenomenon well.
The Elasto-Plastic and Geometrically Nonlinear Finite Element Model of Space Beam Considering Restraint Torsion
Authors: Nie G.J. , Zhong Zheng
Published: March 2009

A new elasto-plastic and geometrically nonlinear finite element model of space beam
considering restraint torsion and the coupling effect of deformations is presented in this paper. The
warping restraint torsion and the coupling effect of deformation are considered in the displacement
formulation of arbitrary point on the space beam. The geometrical relationship of arbitrary point is
derived according to the definition of Green strain. The elasto-plastic and geometrically nonlinear
finite element model of space beam is derived using Updated Lagrange description. The effect of
axial force, shearing force, biaxial bending moment, moment of torsion and bimoment is involved in
the geometrical stiffness matrix of element. The yielding developments both across the section and
along the axis of the member are taken into consideration by selecting Gauss points. The full
historical nonlinear analysis is achieved using the method of load increment and modified
Newton-Raphson method. The validity of the new model derived in this paper is proved by numerical
example. This new model can be used in the elasto-plastic and geometrically nonlinear analysis of
space beam structures constructed by the members of arbitrary cross section.
Knowledge Discovery and Management from Numerical Simulation and its Application to Robust Optimization of Extrusion-Forging Processing
Authors: Jie Hu , Yin Ji Long
Published: March 2009

Numerical simulation technology has been used widely in plastic forming area. However,
the simulation of increasingly complex forming process leads to the generation of vast quantities of
data, which implies much useful knowledge. Consequently domain knowledge is very significant to
product design and process development in metal plastic forming area. The paper presented a new
robust optimization method based on knowledge discovery from numerical simulation. Firstly, the
knowledge discovery model from numerical simulation is established. In this model, interval-based
rule presentation is adopted to describe the uncertainty of design parameters quantitatively to enhance
the design robustness. Secondly, the optimization process based on knowledge discovery and
management is presented, and genetic arithmetic is used to obtain the robust optimization parameter.
Finally, the application to robust optimization of extrusion-forging processing is analyzed to show the
scheme to be effective. The proposed method can overcome the pathologies in simulation
optimization and improve the efficiency & robustness in design optimization.
Chitosan/Heparin Polyelectrolyte Complex Nanoparticles (100~200nm) Covalently Bonded with PEI for Enhancement of Chondrogenic Phenotype
Authors: Lee Hyun Jung , Park Keun Hong , Park So Ra , Min Byoung Hyun
Published: March 2009

Acknowledging the supportive influence of matrix molecules on the chondrocytic
phenotype, we combined heparin and chitosan to develop a novel biomaterial, supporting
chondrogenesis. Chitosan had been shown as a promising structural material for a number of tissue
engineering applications. Similar to heparin, one of the glycosamino-glycans (GAGs) had been
known to exert various influences on the biological activities. In this study we evaluated the
potential of heparin/chitosan polyelectrolyte complex materials for controlling the proliferation and
differentiation of chondrocytes. The heparin/chitosan polyelectrolyte complex was coated over the
polyethyleneimine (PEI) layer precoated on the commercial polystyrene dish. When examined by
using human chondrocyte cell line (C28/I2), the heparin/chitosan surfaces supported well not only
the cell proliferation but also the chondrocytic functions, such as expression of collagen type II.
These results indicated that the heparin/chitosan complex could be used to modulate the activity of
chondrocytes in vitro.
Preparation and Characterization of β-Tricalcium Phosphate Nanofibers via Electrospinning
Authors: Tadjiev Timur R. , Chun Sung Su , Kim Hong Mi , Kang Inn Kyu , Kim Suk Young
Published: March 2009

β-tricalcium phosphate (TCP) ceramic nanofibers via electrospinning route have been produced
using β-TCP sol, which was prepared by the mixing of calcium nitrate tetrahydrate and triethyl
phosphate as Ca sand P precursors, respectively. The as-prepared sol was tightly caped and aged in
a drying oven at 90 °C for 16 hrs. The aged sol was evaporated in opened containers at 35 °C to
reach a proper value of viscosity (100 cPs). Viscous solution was prepared by the mixing of β-TCP
sol and high-molecular weight PVP to obtain appropriate viscosity for electrospinning. The mixed
solution of β-TCP and PVP with various ratios were vigorously mixed using hot plate/stirrer for 24
hrs and then electrospun. The as-electrospun β-TCP nanofibers were dried in a drying oven at 60°C
for 12 hrs and then heat-treated at 500, 600, 700 and 800 °C at 1°C/min heating rate in air. Surface
morphology and phase identification of as-spun and heat-treated β-TCP nanofibers were studied.
The results have shown that ratio between PVP and β-TCP sol and heat-treatment conditions
significantly affected the crystalline phase and morphology of β-TCP nanofibers.
Investigations on the Mechanical Properties and Formability of Friction Stir Welded Tailored Blanks
Authors: Buffa Gianluca , Fratini Livan , Merklein Marion , Staud Detlev
Published: March 2009

Tight competition characterizing automotive industries in the last decades has determined
a strong research effort aimed to improve utilized processes and materials in sheet stamping. As far
as the latter are regarded light weight alloys, high strength steels and tailored blanks have been
increasingly utilized with the aim to reduce parts weight and fuel consumptions. In the paper the
mechanical properties and formability of tailored welded blanks made of a precipitation hardenable
aluminum alloy but with different sheet thicknesses, have been investigated: both laser welding and
friction stir welding have been developed to obtain the tailored blanks. For both welding operations
a wide range of the thickness ratios has been considered. The formability of the obtained blanks has
been characterized through tensile tests and cup deep drawing tests, in order to show the formability
in dependency of the stress condition; what is more mechanical and metallurgical investigations
have been made on the welded joints.
Numerical Modelling and Analysis of Ductile Crack Propagation in Blanking Process Using Modified Nodal Release Method
Authors: Behrens Bernd-Arno , Sidhu Kanwar Bir
Published: March 2009

Ductile fracture processes for discrete crack propagation using nodal release approach is
well established for modelling crack in metal sheet. In this method, the crack is assumed to initiate
or propagate along the element edges; hence, a new crack is implemented in the FE mesh. In
Blanking process, the crack trajectory is unknown; therefore a very fine mesh is required to
simulate a realistic crack propagation using the nodal release method. Consequently, the nodal
release method has to be modified in which first the direction of crack extension is calculated and
then, accordingly, the local element topology near the crack-tip is modified such that the nodes of
elements are moved to predicted crack-tip in order to accommodate the crack extension. The
advantage of this method is that it is possible to model the predicted crack with only slight
modification in the local mesh near to the crack tip. However, it is necessary to transfer history
variables from old local elements of previous increment to the new local elements of the current
increment at the vicinity of crack-tip. But this method can lead to slight loss of accuracy to predict
the subsequent crack extension due to interpolations. However, the advantage of this method is that
remeshing can be either completely eliminated or reduced to a greater extend during the simulation.
Therefore, in this paper, modified nodal release method for modelling ductile crack propagation
in blanking process with the uncoupled damage approach is presented, and is further implemented
in commercial FE software - MSC.Marc® together with predefined user-subroutines
Improving the Cut Edge by Counter-Shaving
Authors: Hoffmann Hartmut , Hörmann Florian
Published: March 2009

In blanking operations the cut edge of the sheet metal is not clear due to fracturing and
burr formation by the shearing process. For precision parts with high quality and dimensional
accuracy, often secondary machining is necessary. Shaving, in particular, counter-shaving, is a
shearing operation to improve the cut edge quality of a blanked part or punched hole in two stages.
This paper introduces a progressive die tool to realize the counter-shaving process on a single acting
press. In order to realize the shaving operation in the opposite punching direction, the punch needs
to move in counter direction. The burr and fracture zone left on the sheet metal after the first stage
will be removed by the counter-shaving operation. By choosing the right process parameter a sharpedge
transition is formed, without any rollover, between the upper surface of the sheet metal and the
sheared-edge. Different punch geometries as well as the corresponding process parameters were part
of the research work in order to improve the cut edge. Experimental and FEM results are presented
for two sheet metal materials at three thicknesses.
Development of Cooled Tools for Press Hardening of Boron Steel Sheets
Authors: Kolleck Ralf , Pfanner Stefan , Warnke E.P
Published: March 2009

Two central topics of modern automotive constructions refer to automotive lightweight
constructions and safety; this is best indicated by the most various developments in the context of
body constructions. The consistent evaluation of cars by means of crash tests has led to the fact that
new manufacturing variants combined with the use of high and ultra high strength materials
represent a fundamental part of the body in white. One possibility to form such materials is given by
the hot forming process. An innovative approach, namely to improve this procedure in economic
and technological terms, is represented by the new tool system for tempered forming processes
carried out at the Institute Tools & Forming (T&F). The integration of most complex cooling duct
geometries by casting integral tube networks into the tool represents an innovative possibility to
improve the cooling performance combined with the reduction of the cycle times.
Effect of Heat Treatment and Transformation on Bending Angle in Laser Forming of Titanium Foils
Authors: Otsu Masaaki , Ito Yasuhiro , Ishii Akira , Miura Hideshi , Takashima Kazuki
Published: March 2009

Pure titanium foils were bent by laser forming and the effect of c-d transformation and
history of heat treatment of specimen on bending angle was investigated. The thickness of specimens
was changed from 40 to 100om, the length of them was 20mm and the width of them was 10mm. The
specimens were annealed at 600-1100oC for 30 minutes in argon atmosphere. A 20W YVO4 laser was
employed and laser power was changed from 2 to 16W. From the experimental results, when laser
power was increased, bending angle also increased and it was dramatically changed at the laser
powers occurring c-d transformation and melting. Bending angle increased as grain size increased
and it jumped up when grain size exceeded the foil thickness and then became constant. Bending
angle decreased by annealing after forming and degree of decrease was greater when the annealing
temperature before forming was lower.
Formability and Microstructure of AZ31 Magnesium Alloy Sheets
Authors: Forcellese Archimede , El Mehtedi Mohamad , Simoncini M. , Spigarelli Stefano
Published: March 2009

The formability of AZ31 magnesium alloy sheets has been investigated in the
temperature range varying from 200 to 300°C. Forming limit diagrams have been obtained by
performing Nakazima-based tests. The different straining conditions have been investigated using
sheet blanks with several length to width ratios. The forming limit curves have been related to the
microstructural evolution occurring during deformation. The forming limit diagrams have shown a
remarkable increase in formability with temperature that could be related to the occurrence of full
dynamic recrystallization at 300°C.
Experimental Procedure Definition for Evaluating the Formability at Warm Temperatures of AZ31 Magnesium Alloy
Authors: Palumbo G. , Sorgente Donato , Tricarico Luigi
Published: March 2009

In the present work the definition of a test procedure for evaluating the formability of Mg
alloy thin sheets was investigated taking into account both temperature and strain rate. A numericalexperimental
approach was adopted by the authors: numerical simulations were run with the aim of:
(i) defining the punch geometry of the formability test equipment in order to have a uniform, fast
and constant temperature distribution on the specimen; (ii) setting the test operating conditions in
order to force the specimen failure in a region where temperature and strain can be easily acquired.
Some formability tests were performed and strain fields were measured using an optical
measurement system.
Die Forming of Medical Forceps
Authors: Aoki Isamu , Masahiro Sasada , Fuchiwaki Tadao
Published: March 2009

Medical examinations and treatments using endoscopes are becoming increasing common
due to their minimally invasive nature. Many types of medical devices for endoscopic therapy are
available, and of these, forceps are most frequently used. Forceps prices are on the whole high, and
one of the reasons for this can be attributed to the manufacturing method. Currently forceps parts are
made by cutting or metal removal process. By replacing these methods with die forming, stable supply
at low costs should be possible. This paper describes a study proposing and developing a forceps
manufacturing method by die forming, and describes the successful results. It also reports the
evaluation carried out on functions of the prototyped forceps and the proposed method of changing
the shape of products for which die forming is not suitable.
Stamping of One-Piece Automobile Steel Wheels from Tube
Authors: Abe Y. , Watanabe J. , Mori Kenichiro
Published: March 2009

A multi-stage stamping process of one-piece automobile steel wheels from tubes was
developed to decrease the loss of material for the blanking. In this process, the tube is nosed into a
cup with a central hole, and then the taper bottom and side wall of the cup are formed into disk and
rim portions of the wheel, respectively. The tube is produced by bending a rectangular sheet into a
tube and by welding both edges of the bent sheet to prevent the loss of material for the blanking.
The stamping sequence of the one-piece wheels was designed by finite element simulation. The
central hole of the cup was decreased to a desired diameter of the hub hole without buckling and
wrinkling by a 5-stages nosing operation. The taper bottom of the cup was reversely drawn, and
then was flared without folding by 2 stages. The wall thickness of the formed wheel was thick and
thin in the disk and rim portions, receptively, and thus the requirement of strength of wheels is
satisfied. A one-piece wheel having a hub hole was successfully formed by the designed sequence
in a miniature experiment.
Validation of a New Finite Element for Incremental Forming Simulation Using a Dynamic Explicit Approach
Authors: Henrard Christophe , Bouffioux Chantal , Duchêne Laurent , Duflou Joost R. , Habraken Anne Marie
Published: March 2009

A new method for modeling the contact between the tool and the metal sheet for the
incremental forming process was developed based on a dynamic explicit time integration scheme.
The main advantage of this method is that it uses the actual contact location instead of fixed
positions, e.g. integration or nodal points. The purpose of this article is to compare the efficiency of
the new method, as far as accuracy and computation time are concerned, with finite element
simulations using a classic static implicit approach. In addition, a sensitivity analysis of the mesh
density will show that bigger elements can be used with the new method compared to those used in
classic simulations.
Determination of Strain in Incremental Sheet Forming Process
Authors: He S. , Gu J. , Sol Hugo , Van Bael Albert , van Houtte Paul , Tunckol Yasemin , Duflou Joost R.
Published: March 2009

A simplified method to determine the strain distribution during incremental
forming of a cone is proposed in this paper. Because of the symmetry of the deformed
part, the strain can be derived using the results obtained from a limited number of
consecutive tool contours instead of going through the whole process. Comparisons
made between the measured and simulated results show that the proposed method can
be applied to determine the strain encountered in such kind of incremental forming
process where axi-symmetric parts are formed.
Incremental Forming Process for the Accomplishment of Automotive Details
Authors: Governale A. , Lo Franco A. , Panzeca A. , Fratini Livan , Micari Fabrizio
Published: March 2009

In the last decades the scenario of the industrial production is remarkably changed, since
new market requirements have to be faced by the industries. The market, actually, more and more,
asks for vary models and niches product. The necessity to intercept dynamically and to satisfy the
demands for the market, driver of the innovation process, involves the necessity to reduce the Timeto-
market introducing to new methodologies of engineering, like the 3D-prototyping, for the
qualitative and structural analysis of the final component. For these reasons, at the beginning of the
nineties, a new philosophy of sheet metal forming process begins to assert on the industrial scene,
whose basic logic is to obtain the shape wished through the progressive action of a tool of simple
shape.
In this job the application of the simplest process of incremental process on an industrial detail -
famous in international field like SPIF (Single Point Incremental Forming) - will be described. The
process is intrinsically flexible, and therefore is adapted to the rapid prototyping.
The cases are still least, notice in the scientific literature, in which the details of industrial
interest have been developed by Incremental Forming process; for this reason, the subject of this job
is focused on the evaluation of the possibility to obtain real components of the automotive industry
through the SPIF process. The job has been carried out in the R&D laboratory of "Fontana Pietro
S.p.A.”, leader in the field of die manufacturing and stamping of component of the automotive
industry. In particular, two parts of automotive auto body of aluminium sheets have been
considered. It has been lead an analysis of technological and process feasibility, optimizing tool path
considering experiences to obtain a product/process for the production of auto body prototypes.
Evaluation of the Annealing Temperature Effect on the Mechanical Properties of a IF Steel by Means of Physical Simulation
Authors: Cantemir Doru , Valentini R.
Published: March 2009

Interstitial-free (IF) sheet steels are largely used in automotive deep-drawing applications,
as they offer both good formability and adequate strength for auto bodies. In order to improve the
corrosion resistance they are usually coated, mostly by hot-dip galvanizing. In the present work two
IF steels purposely designed for a specific continuous hot-dip galvanizing line are investigated. The
employed methodology, based on physical simulation, is presented and discussed in the paper. Its
reliability is demonstrated by comparing some experimental and industrial results. The simulated
specimens are tensile tested and the effects of annealing temperature and line speed on their
mechanical properties are evaluated.
Laser Beam Welding of New High Strength Steels for Auto Body Construction
Authors: Haferkamp H. , Meier O. , Harley K.
Published: March 2009

With the regard to the development of modern car bodies the focus lies on low production
costs, environmental sustainability and high security standards. In order to meet these requirements
the weight of modern car bodies has to be reduced consistently. Amongst other things, this becomes
possible by the use of new high and ultra high strength steels. These materials are characterised by
their high strength, good ductility and a high absorption capacity. In addition they have a lower
density in comparison to other steels. TRIP and TWIP steel belong to these high and ultra high
strength steels as well as iron-manganese steel.
The development of new materials also puts new demands on the joining technologies used for
producing semi finished products and parts of car bodies. Due to its high flexibility, its good
automation and the minor influence on the work piece, laser beam welding is an established
procedure in the automotive series production. The high cooling rates in combination with a carbon
equivalent of the new materials which is usually higher then 0.4% lead to a martensitic
solidification of the weld seam. Martensite is characterized by its low ductility and thus affects the
forming capability as well as the absorption capacity of the welded parts.
In order to avoid this effect a new process has been developed within the scope of the
collaborative research program 362 (SFB 362, 1993-2005) at the Laser Zentrum Hannover. Using
that process the weld seam structure is inductively annealed directly after the welding process.
Experiments with high strength steel like TRIP700 and H320LA have shown that the tempering
leads to an increase of ductility.
The process is suitable for butt joints and overlap joints and is to be transferred into industrial usage
within the scope of the project “Laser Beam Welding of Car Body Parts Made of High and Ultra
High Strength Steel”. Based on the results obtained in the SFB 362 continuous investigations will
be made in order to qualify the process for boron alloyed steel and iron-manganese steel.
An Intelligent System for Modeling and Material Selection for Progressive Die Components
Authors: Kumar S. , Singh R.
Published: March 2009

This paper presents an intelligent system for modeling and material selection for
progressive die components. The proposed system comprises of two modules, namely INTPMOD
and MATSEL. The first module INTPMOD is constructed for modeling of die block, stripper plate,
punch plate, back-up plate, die-set and die assembly of progressive die automatically in the drawing
editor of AutoCAD. The second module MATSEL is developed for material selection for
progressive die components. Both the modules are coded in AutoLISP language and designed to be
loaded into the prompt area of AutoCAD. An illustrative example is included to demonstrate the
usefulness of the system modules. The proposed system is implemented on a PC having AutoCAD
software and its low cost of implementation makes it affordable for small and medium-size sheet
metal industries.
Modeling Sheet Metal Integrated Production Planning for Laser Cutting and Air Bending
Authors: Verlinden Bert , Cattrysse Dirk , Duflou Joost R. , Van Oudheusden Dirk
Published: March 2009

Over the past few years both sheet metal process planning and production planning issues
received increased attention. For process planning of the laser cutting process, nesting algorithms
are developed in order to decrease the waste material. Additionally, algorithms are available for
path planning, i.e. determining the best sequence for cutting the different parts. Production planning
is mainly performed based on the ability to fill a sheet. For air bending, process planning focuses on
bend sequencing and tool selection, while production planning optimization aims at minimizing
time consuming setups between the different production layouts at the press brake. However, when
integrating both processes, the benefits from individual optimization counteract one another: good
nestings at the laser machine can create additional setups at the press brake, hence increasing the
makespan. An integrated approach is proposed to verify whether this problem can be solved by
already taking into account possible setups at the press brake in the early nesting stage. Integration
of both processes aims at an optimal combination of parts on a sheet and minimization of the setups
at the press brake. In this paper, an overview of a modeling effort addressing both goals is proposed.
When combining parts on a sheet, preference is given to parts requiring the same production layout
at the press brake. If this is impossible, production layouts with low changeover times are preferred.
Industrial cases are used to verify the applicability of the proposed model. The results are compared
to a reference approach where nesting is performed with dedicated software and planning for air
bending is based on an operator’s experience. Compared to this reference approach, a makespan
reduction and a setup time reduction can be observed. The planning is generated almost
instantaneously and no additional sheets are required compared to the reference approach. Future
research will focus on expanding the model and verifying its applicability on a larger data-set.
A More Efficient Method for Clustering Sheet Metal Shapes
Authors: Lo Valvo Ernesto , Licari Roberto
Published: March 2009

The nesting of two-dimensional irregular shapes is a common problem which is
frequently encountered by a number of industries where raw material has to be, as economically as
possible, cut from a given stock sheet. A frequently recurring problem as far as cutting stock is
concerned, is how to obtain the best nesting of some pieces of flat patterns which occupy minimalarea
convex enclosure. The area of convex enclosure is related to the convex hull of the union of
patterns which can be imagined as a large rubber band surrounding the set of all polygons.
Our goal is to automatically obtain the smallest area convex shape containing all the patterns.
As a matter of fact, Cheng and Rao have proposed an heuristic “stringy effect” procedure for
clustering which follows a descending order of area of patterns. The “stringy effect” is able to put
each new piece in a position which minimises the value of the distance between the centroid of each
added piece and the centroid of the already formed cluster.
The procedures till now shown in literature are quite complex. They make use of sliding techniques,
and are not able to effectively work with relatively multiply-connected figures. In particular, the
different procedures proposed are based on the No Fit Polygon computation of non-convex
polygons, which often generates holes.
This work is a proposal for a more efficient method, which can be used in heuristic procedure.
In this paper a new procedure for the calculation of “No Fit Polygon” (NFP) of non-convex
polygons is presented. Given two non-convex polygons, the algorithm is able to calculate their NFP
very quickly and without any approximation by a polygon clipping method. By iterating this
procedure with every polygon of our set, and positioning them using the “stringy effect” technique,
it is so possible to obtain a convex shape that contains all the patterns, having the minimal area.
Determination of Yield Locus of Sheet Metal at Elevated Temperatures: A Novel Concept for Experimental Set-Up
Authors: Ghiotti Andrea , Bruschi Stefania , Bariani Paolo F.
Published: March 2009

The constant demand of increasing performances and safety in vehicle industry has led
significant innovations in the materials used in sheet metal forming processes. In particular, multiphase
steels and lightweight alloys have known higher and higher importance, thanks to the
development of new stamping processes at elevated temperatures, which guarantee, at the same
time, better formability, lower springback and more accurate micro-structural control in the formed
sheets. With respect to these aspects, the correct design and optimization of the new processes
cannot prescind of the mechanical characterization of materials in biaxial stress conditions,
especially when it strongly varies according to the stress and temperature. In this paper, a novel
experimental set-up is presented for determining the in-plane yield locus of sheet metals at elevated
temperatures. A cruciform specimen, whose geometry was optimized by numerical simulation, is
used for the study of the yield locus in the range of biaxial tensile stresses. The test machine concept
is based on punch-wedge mechanism, which uses the vertical movement of the press for the
deformation of the specimen along two perpendicular axes. In the first part of the paper, the
optimization of the cruciform specimen by thermo-mechanical FE analyses is outlined. Details on
the experimental set-up are then given with the description of the apparatus, the measurement of
plastic strains and the heating system for tests at elevated temperatures.
A Study on the Fretting Wear Resistance of a Zirconium Alloy with the Variation of Supporting Spring Properties
Authors: Lee Young Ho , Kim Hyung Kyu
Published: March 2009

An effort has been made in the present investigation to evaluate the wear resistance of
nuclear fuel rods with a variation of the supporting spring shapes and their stiffness by conducting
fretting wear tests in room temperature air and water. With increasing slip amplitude, the wear
volume and maximum wear depth are increased with increasing slip amplitude. However, these are
not linearly increased with increasing spring stiffness. After the wear test, the worn surfaces were
observed to investigate the debris behavior and wear mechanism by using an optical microscope
(OM). The results indicated that almost all of the wear debris remained between the contacting
surfaces and the wear debris layers were well developed in room temperature air. Besides, some of
the debris also remained on the worn surface in room temperature water. This result shows that the
remaining debris effect on the worn surface was more dominant than the spring stiffness one. So, in
order to improve the fretting wear resistance of a nuclear fuel rod, it is necessary to consider the
debris behavior between contacting surfaces even though the supporting spring shape was
optimized by considering the contact mechanics, material compatibility, etc. From the experimental
results, the fretting wear mechanisms and the effect of spring properties were discussed.
Surface Friction Welding of Thin Metal Sheets
Authors: Kim Sung Joon , Lee Chang Gil , Han Heung Nam , Kang Suk Hoon , Oh Kyu Hwan
Published: March 2009

A novel process for butt welding of thin metal sheets was developed and named as surface
friction welding (SFW), which utilizes friction heat and severe plastic deformation like friction stir
welding (FSW). The joining mechanism of the SFW is based on not stirring by the pin tool but surface
friction between tool shoulder and joining metals. The developed method was successfully applied to
butt welding of various metal sheets thinner than 1.5 mm thick. This paper deals with the principle of
SFW, the difference between FSW and SFW, the effect of welding parameters, and the microstructure
and mechanical properties of welded sheets.
Evaluation of Fretting Fatigue Life for Steam Generator Tubes in Nuclear Power Plants
Authors: Park Dae Kyu , Woo Seung Wan , Chung Il Sup , Chai Young Suck , Kwon Jae Do
Published: March 2009

Studies on the strength and fatigue life of machines and structures have been conducted in
accordance with the development of modern industries. In particular, fine and repetitive cyclic
damage occurring in contact regions has been known to have an impact on fretting fatigue fractures.
INCONEL alloy 600, 690 and INCOLOY alloy 800 are iron-nickel-chromium alloy having excellent
resistance to many corrosive aqueous media and high-temperature atmospheres. These alloy are used
extensively in the nuclear power plants industry, the chemical industry, the heat-treating industry and
the electronic industry. In this paper, the effect of fretting damage on fatigue behavior for INCONEL
alloy 600, 690 and INCOLOY alloy 800 were studied. Also, various kinds of mechanical tests such as
tension and plain fatigue tests are performed. The objective of this study is to guarantee reliability of
the facility applied in a power plant by comparing three materials in respect to fretting fatigue.
Fracture Behavior of Ceramic Matrix Composites during Monotonic and Cyclic Loadings
Authors: Kim Jeong Guk , Liaw Peter K.
Published: March 2009

The fracture behavior of ceramic matrix composites (CMCs) was investigated using the
infrared (IR) thermography nondestructive evaluation (NDE) technique during monotonic and
cyclic loadings. The CMCs used for this investigation are continuous Nicalon (silicon carbide fiber)
fiber reinforced calsium aluminosilicate (CAS) glass-ceramics matrix composites. During
monotonic tension and cyclic fatigue loadings, IR camera was used for in-situ monitoring of
temperature evolution, and the temperature changes during testing were measured. Microstructural
characterizations using scanning electron microscopy (SEM) were performed to investigate fracture
modes and failure mechanisms of Nicalon/CAS samples. In this investigation, the NDE technique
and SEM characterization were employed to facilitate a better understanding of damage evolution
and progress of Nicalon/CAS composites during monotonic and cyclic loadings.
Microstructure and Mechanical Properties of Mg-Al-Ca Alloys with Yttrium Addition
Authors: Kim Young Kyun , Son Hyeon Taek , Lee Jae Seol , Oh Ik Hyun , Kim H.J. , Bae Jung Chan
Published: March 2009

The aims of this study are to investigate the effect of Y (yttrium) addition in the Mg-Al-
Ca alloys on microstructure and mechanical properties. In additions, the alloys were solution treated
in order to achieve a better understanding of the precipitation mechanisms. The as-cast
microstructure of Mg-5Al-3Ca alloy and Mg-5Al-3Ca-xY alloys contains dendritic α-Mg matrix
and eutectic intermetallic compound at grain boundary. The hardness values of Mg-Al-Ca alloy
with Y additions were slightly increased than that of Mg-Al-Ca with no Y addition. It is because of
reduction of α-Mg phase and presence of (Mg,Al)2Ca and Al-Y rich intermetallic phase at grain
boundary and α-Mg matrix grains. Also, hardness value of yttrium (Y) containing alloys was
increased with increasing Y contents. Compared to Mg-5Al-3Ca alloy, maximum strength and yield
strength of the alloys with Y additions have slightly increased with increasing Y additions in the
case of as-cast samples.
On the Applicability of the Ho-Kalman Minimal Realization Theory
Authors: Spadavecchia Roberto , de Stefano Alessandro , Sabia Donato
Published: March 2009

The reduced-order model of a time-invariant linear dynamical system, excited by a force
of an impulsive type, may be readily obtained using the Ho-Kalman minimal-realization algorithm
[1]. The method is based upon a particular factorization of the Hankel matrix in the Markovian
representation of the discrete-time process. For stochastic systems, the applicability of the theory
has been demonstrated by Akaike [2] on the assumption that the excitation is a zero-mean white
noise of a gaussian type. Some of the most widely known output-only identification methods, such
as Eigensystem Realization Algorithm (ERA), Canonical Variate Analysis (CVA), and Balanced
Realization (BR)) are based upon the above-mentioned work, with the aid of a robust factorization
technique, such as Singular-Value Decomposition (SVD). Notwithstanding the growing popularity
of the above methods, some aspects of their applicability are not yet understood. Two points are of
particular interest: the first regards the applicability of the theory in highly damped systems; and the
second regards its applicability to systems driven by excitations different from the one
hypothesized. The aim of the present work is to define a reliable test on the hypotheses. Some
numerical and experimental results are presented.
Damage Detection Using Prior Wavelet Decompositions
Authors: Chetwynd Daley , Worden Keith , Mustapha Faizal , Rongong Jem A.
Published: March 2009

This work was conducted as part of the European Union project ARTIMA and it
investigates the effectiveness of wavelets in damage detection. It examines whether a prior wavelet
decomposition of Lamb wave responses facilitates the classification of structural damage. The
structure in question is an aluminium plate with viscoelastic-mounted transducers, and the damage
took the form of saw cuts on the plate. The novelty detection technique of outlier analysis was used
to classify the damage.
Monitoring of Growing Fatigue Damage Using the E/M Impedance Method
Authors: Xing Ke Jia , Fritzen Claus Peter
Published: March 2009

The electro-mechanical (E/M) impedance-based method is one important and effective
method in damage detection. The basic concept of the impedance method is to monitor the
variations in the structural mechanical impedance spectrum caused by damage in the structure.
Comparing the impedance spectrum to a baseline measurement of the undamaged structure, the real
part of the E/M impedance reflects the state of structural health in the local area, therefore, the
structural damage can be localized, a local-area self-sensing method is implemented.
In this paper, an aluminium plate mounted on an electromagnetic shaker is used to detect
growing fatigue damage using the impedance method. The growing damage is documented by an
increase of the indicators. For the case of a static artificial damage the concept is also demonstrated
to an Airbus A320 fuselage part using 9 self-sensing elements on the stringers.