bluuebunny/crossref_metadata_2025 huggingface dataset:
Prevention of Tissue Adhesion by a Spontaneously Formed Phospholipid Polymer Hydrogel
Authors: Kimura Mizuna , Konno Tomohiro , Takai Madoka , Ishiyama Noriyuki , Moro Toru , Ishihara Kazuhiko
Published: March 2009

We investigated phospholipid polymer hydrogels containing Fe3+ ions (PMA/PMB/Fe
hydrogel) for their use as antiadhesive materials in the healing tissues. These hydrogels were
prepared from the aqueous solutions of poly(2-methacryloyloxyethyl phosphorylcholine (MPC)-comethacrylic
acid) (PMA) and poly(MPC-co-n-butyl methacrylate) (PMB). The PMA/PMB hydrogel
is formed by the intermolecular interactions between PMA and PMB, and it reversibly dissociates
under physiological conditions. The addition of Fe3+ ions could control the gelation time and the
dissociation time. Mechanical properties such as the gelation time and viscoelastic properties can be
controlled by the FeCl3 concentration. With regard to biocompatibility, no evidence of
inflammation was observed in vivo. Therefore, the PMA/PMB/Fe hydrogel has a potential to be
used as an antiadhesive material.
Surface Modification by Grafting with Biocompatible 2-Methacryloyloxyethyl Phosphorylcholine for Microfluidic Devices
Authors: Sibarani James , Konno Tomohiro , Takai Madoka , Ishihara Kazuhiko
Published: March 2009

Non-biofouling surfaces with polymer-based substrate were prepared for manufacturing
microfluidic devices. It was done by constructing biocompatible poly(2-methacryloyloxyethyl
phosphorylcholine(MPC)) brushes using surface-initiated graft polymerization method based on
dithiocarbamate as photoiniferter. The density and length of the polymer chains were varied by
changing the composition of the photoiniferter moiety in the base polymer (macrophotoiniferter)
and the photoirradiation time, respectively. The molecular weight and thickness of the poly(MPC)-
grafted chains were 320 kDa and 95±14 nm, respectively. Characterizations of the poly(MPC)
modified surfaces were conducted by water contact angle, X-ray photoelectron spectroscopy,
atomic force microscope. Protein adsorption resistance of these modified surfaces was then
investigated by contacting with human plasma protein dissolved in phosphate buffered saline. These
poly(MPC)-modified surfaces effectively reduced protein adsorption.
Coating of Anionic Phospholipid Polymer onto Silica-Based Microchannel to Minimize Nonspecific Protein Adsorption
Authors: Xu Yan , Takai Madoka , Konno Tomohiro , Ishihara Kazuhiko
Published: March 2009

An anionic phospholipid copolymer PMBSSi was synthesized to construct a permanent
coating with protein resistant units (2-methacryloyloxyethyl phosphorylcholine, MPC) as well as
surface charges onto the silica based (quartz and glass) microchannel through a one-step
modification. The coating showed a high property of minimizing the non-specific adsorption of
both anionic and cationic proteins to a very low extent of less than 0.05 μg /cm2 on glass substrates.
In addition, a significant cathodic EOF ((1.0±0.1) ×10-4 cm2/V·s) with approximately one-half of
the EOF of the uncoated microchannel was achieved in coated microchannel at neutral pH. As a
conclusion, PMBSSi coating is a simple but highly effective modification for reducing nonspecific
protein adsorption, and promising to be applied in electrokinetic microfluidic systems.
Blood Compatibility of Novel Zwitterionic PEG-Grafted Nitinol Alloy for Peripheral Arterial Stents
Authors: Kim Jae Hoon , Son Jun Sik , Park Kwi Deok , Kim Jong Man , Kim Jae Jin , Ahn Kwang Duk , Han Dong Keun
Published: March 2009

In this study, newly synthesized zwitterionic PEG was grafted on Nitinol alloy using
oxidation treatment. The surface property and blood compatibility of surface-modified Nitinols
were examined. The results of surface analysis showed that the contact angle and the ratio of
oxygen to carbon significantly decreased with Nitinol alloys. The total amount of fibrinogen (0.095
μg/cm2) adsorbed onto TiNi-PEG2K-N+-S- was lower than that of TiNi control (0.12 μg/cm2). The
platelet adhesion decreased in the order of TiNi control > TiNi-MPEG2K > TiNi-PEG2K-N+-S.
Particularly, zwitterionic PEG with PEG2K was proven better than any others. The results indicated
that zwitterionic PEG surface could significantly suppress platelet adhesion and protein adsorption
as compared to other samples. The present study suggested that grafted zwitterionic PEG structure
may possess improved blood compatibility.
Study of Protein Adsorption on Biomaterial Surfaces by SPR
Authors: He Jian , Lü Xiao Ying , Hong Qing Yue , Lu Zu Hong , Huang Yan , Sun Pai Zheng
Published: March 2009

The aim of this study was to set up a SPR sensor and to investigate protein
adsorption onto biomaterial surface using it. Methods: The adsorption of human albumin (Alb),
fibrinogen (Fib) and immunoglobulin G (IgG) onto polyurethane (PU) H50-50 and Au surface were
measured using this SPR sensor. Results: The results of protein adsorption showed that the amount
of Alb, Fib and IgG adsorbed on PU (H50-50) are smaller than Au, and on these two material
surfaces, the amount sequence of adsorbed protein is: IgG> Fib > Alb. Both the Alb/Fib ratio and
Alb/IgG ratio on PU (H50-50) surface are higher than Au. Conclusion: The antithrombogenicity of
PU (H50-50) is better than Au.
In Situ Investigation of Biomaterial Surfaces Using LDH and ELISA
Authors: Shao Zhen Yi , Zhao An Sha , Yang Ping , Zhou Hong Fang , Huang Nan
Published: March 2009

Lactate dehydrogenase (LDH) and enzyme-linked immunosorbent assay (ELISA) have
attracted much attention recently for the evaluation of blood compatibility of biomaterials due to
their convenience and quantifiability. In this paper, the use of LDH and ELISA is described for in
situ investigation of platelet behavior on biomaterial surfaces, including quantification of platelet
adhesion and platelet activation, after suitable testing conditions have been established. The
material samples investigated in these tests included low temperature isotropic carbon (LTIC), Ti-O
films, and phosphorus- and aluminum-doped TiO2 films. The evaluation results show that the
lowest platelet adhesion and activation are observed on phosphorus-doped TiO2 films while the
highest platelet adhesion and activation are observed on LTIC. In addition, conventional platelet
adhesion experiments were performed for comparison, and yielding similar evaluation results as
LDH and ELISA. It is suggested that LDH and ELISA tests can be successfully applied to evaluate
the blood compatibility of biomaterials and can show many advantages, such as quantification,
reliability and objectivity, compared with conventional platelet adhesion test.
Radiolytic Synthesis of Hybrid Silver Nanoparticles and their Biobehavior
Authors: Park Hae Jun , Kim Hwa Jung , Kim Sung Ho , Oh Seong Dae , Choi Seong Ho
Published: March 2009

The hybrid Silver(Ag) nanoparticles were synthesized by gamma-irradiation, and
characterized by field-emission transmittance electron microscopy (FE-TEM), field-emission
scanning electron microscopy (FE-SEM), and energy dispersive X-ray spectroscopy (EDXS). The
electron microscopy images show that well-dispersed Ag nanoparticles of about 3-7 nm were
loaded to the outer and inner side of SiO2 nanoparticles of about 5-30 nm. Antifungal efficiency of
the hybrid nanoparticles was tested against Aspergillus flavus ATCC 64025, Aspergillus fumigatus
ATCC 16424, Aspergillus terreus ATCC 46941, Candida albicans ATCC 10231, Candida albicans
A207(clinical isolate), Candida glabrata ATCC 48435, Candida krusei ATCC 6258, Candida
lusitaniae ATCC 42720, Candida parapsilosis ATCC 34136, Candida tropicalis ATCC 13803,
Cryptococcus neoformans ATCC 36556, and Mucor ramosissmus ATCC 90286. At the presence of
hybrid Ag nanoparticles at 1 ppm, they did not grow fully even after 58 hrs except for Cryptococcus
neoformans ATCC 36556. The hybrid Ag nanoparticle can be used for antifungal agents.
Growth of Smooth Muscle Cell and Endothelial Cell on PLGA Film Containing EGCG
Authors: Chung Jin Hyun , Lim Hye Ryeon , Lee Tek Hyung , Lee Mi Hee , Woo Yeon I , Baek Hyun Sook , Lee Seung Jin , Kim Jeong Koo , Park Jong Chul
Published: March 2009

Poly (D,L-latic-co-glycolic acid) (PLGA) has been used as the artificial scaffold for
blood vessel formation. In order to hinder smooth muscle cell (SMC) angiogenesis, new scaffold
design method of loading Epigallocatechin 3-O-gallate (EGCG) on PLGA film was introduced.
PLGA and EGCG were dissolved in acetone and film-shape scaffold was manufactured. Antiangiogenetic
effect of EGCG released on scaffold was analyzed for SMC and human umbilical vein
endothelial cell (HUVEC) and method for selective inhibition from the difference of growth of
SMC and HUVEC was suggested.
Antibacterial Effect of Oral Rinses Containing Phytosphingosine
Authors: Oh S.H. , Choi M.J. , Kim B.I. , Kim Kwang Mahn , Kim Kyoung Nam
Published: March 2009

The main objective of this study was to manufacture an oral rinse using the natural
antibacterial agent (phytosphingosine, Doosan, Korea) for the prevention of periodontal disease and
dental caries. Phytosphingosine is known to inhibit the growth of bacterial strains and induce
apoptotic cell death in human cancer lines. In this study, antibacterial activity and cytotoxicity of
oral rinses were performed with an experimental group containing phytosphingosine(PS) in vitro.
Control groups consist of two Korean products and two American products containing
chlorhexidine and cetylpyridinium chloride, respectively. There was no significant difference
between experimental and control groups in the antibacterial activity and cytotoxicity except for
Chika Chika Liq (p<0.05). According to the results, antibacterial activity of oral rinse containing PS
was 99.62%, the strongest contact inhibition of Streptococcus mutans strain among tested groups. In
the cytotoxicity test of oral rinses, PS had a weaker cytotoxicity than control groups in mouse and
human normal cell lines and showed the strongest cytotoxicity in human oral cancer cell lines (KB
cell). From the results, PS may be widely used as an oral rinse for the healthy and the patients with
oral cancers in the near future.
Effect of Three-Dimensional Scaffold Geometry on Chondrocyte Adhesion
Authors: Lee Seung Jae , Kim Byung , Lim Geun Bae , Kim Sung Won , Rhie Jong Won , Cho Dong Woo
Published: March 2009

This paper compares the characteristics of chondrocyte adhesion on two types of threedimensional
(3-D) scaffold: types A and B. These 3-D scaffolds can be repeatedly constructed with
the same dimensions using microstereolithography, a system that allows the fabrication of predesigned
internal structures, such as pore size and porosity, by stacking the photopolymerized
material. In tissue engineering, chondrocyte adhesion to a scaffold should have a major effect on the
regeneration of cartilage. In this regard, we evaluated chondrocyte adhesion to two types of scaffold
and found that chondrocyte adhesion was better on the type B scaffold than on the type A,
demonstrating the importance of scaffold geometry in chondrocyte adhesion.
Plane Strain Test for Metal Sheet Characterization
Authors: Flores Paulo , Bonnet Félix , Habraken Anne Marie
Published: March 2009

This article shows the influence of a plane strain test specimen geometry on the
measurable strain field and the influence of free edge effects over the stress computation. The
experimental strain field distribution is measured over the whole deformable zone of a plane strain
test specimen by an optical strain gauge. The chosen material is the DC06 IF steel of 0.8 mm
thickness. The stress field is computed for several geometries at different strain levels by a Finite
Element (FE) commercial code (Samcef ®). The results show that the stress field is sensitive to the
specimen’s geometry and also to the tested material (strain field behavior is independent of
material) and, based on results, an optimal specimen geometry is proposed in order to minimized
the stress computation error.
New Forming Processes for Sheet Metal with Large Plastic Deformation
Authors: Groche Peter , Ringler Jens , Vucic Dragoslav
Published: March 2009

Due to the high effort involved, bifurcated constructions in mass market products made
from sheet metal remained largely unused. Extruded profiles with cross-sections containing
bifurcations show the possibility to increase the stiffness and allow modern lightweight design using
load optimized structures as well as in box strap, sandwich and stringer constructions or different
profiles. The two new forming processes linear flow splitting and linear bend splitting developed at
the PtU enable the production of bifurcated profiles in integral style made of sheet metal without
joining, lamination of material or heating of the semi-finished product. These forming processes use
obtuse angled splitting rolls and supporting rolls to transform the sheet metal at ambient
temperature. Whereas the linear flow splitting process increase the surface of the band edge and
forms the band into two flanges. At linear bend splitting a bended sheet metal as semi finished
product is used. Thereby bifurcations at nearly any place of a sheet metal can be produced. Both
processes induce high hydrostatic compressive stresses in the local forming zone during the process
which leads to an increased formability of the material and thereby to the realization of large strains.
Parts produced are characterized by increased stiffness, high surface hardness and low surface
roughness. Experimental investigations have shown an increasing of the band edge surface at
maximum splitting depth up to 1800%. By a following forming process new multi-chambered
structures and integral stringer construction can be realized with thin walled cross-sections from
steel of higher strength.
Off-Set Roller Bending of Aluminium Space-Frame
Authors: Endou Junichi , Katoh Shunji
Published: March 2009

In the proto-type bending machine reported in the previous paper, the Bending Roller
was fixed in the same position during bending. Therefore, almost uniform curvature in longitudinal
direction was obtained. We improved the machine as the Bending Roller can be moved by a servo
motor. By this improvement, we can bend aluminium space-frame into varied curvature in
longitudinal direction. The curvature of a bent aluminium space frame is different from the setting
curvature calculated from the moving position of the bending roller, because so called spring back
occurs. We found out that the abrupt increase of objective curvature causes collapse of the specimen
and we cannot obtain the objective curvature. And the sudden decrease of the objective curvature by
sudden decrease in position of bending roller cannot be realized because of the outbreak of gap
between the bending roller and the bent space-frame. If we avoid the abrupt change of the objective
curvature, we can compensate the spring-back and we can get the objective curvature.
Forming Al and Mg Alloy Sheet and Tube at Elevated Temperatures
Authors: Altan Taylan , Kaya Serhat , Aue-u-Ian Yingyot
Published: March 2009

Experimental investigation on the formability limits of aluminum and magnesium alloys
are conducted through hydraulic bulging and deep drawing. New tube hydroforming tooling was
designed and the submerged tool concept is introduced. Tube hydroforming experiments were
conducted with and without axial feed by using AA6061 tubes. The formability of Mg AZ31-O
sheets are determined by hydraulic bulging using similar submerged tool. Finally the effect of
temperature and initial blank size on the attainable highest punch velocity is investigated and round
cups from Mg AZ31-O were successfully formed in a heated tool with punch speeds up to 300
mm/s.
Mechanics of Tailor Welded Blanks: An Overview
Authors: Zadpoor A.A. , Sinke J. , Benedictus R.
Published: March 2009

Taking advantage of high-tech welding methods, a concept is formed in sheet metal
forming community. The so-called tailor-welded blanks (TWBs) are sheet metals that are welded
together prior to forming. This technology dates back to the 80’s, and numerous studies are
conducted in order to explore different aspects of it. This review paper concerns with mechanics of
TWBs. The paper is divided into three major chapters. The first chapter is devoted to mechanical
properties of TWBs. Tensile testing, tensile properties, and hardness of TWBs are covered in this
chapter. The second chapter deals with the formability of TWBs. The formability testing methods,
effect of different parameters on the formability of TWBs, material flow phenomena, control of
material flow, stress and strain distributions, and springback behavior are covered in the second
chapter. The third chapter is focused on failure and fracture of TWBs. Failure modes and failure
criteria are the principal topics of this chapter.
Double Curvature Springback in Stretch Formed 2024-T3 Aluminium
Authors: McMurray Robert , Leacock Alan G. , Brown Desmond
Published: March 2009

A test rig was developed to investigate springback in stretch draw forming processes,
which are considered to be nominally uniaxial. An interchangeable tool allows the examination
of both single and double curvature surfaces. Two double curvature tools with the following
radii were used in the experiments, (A) 200mm by 450mm and (B) 450mm by 200mm. The
first radius in each case corresponds to the direction of stretch. Obviously the smaller radius
results in a larger moment, which creates a negative springback in the orthogonal direction.
This effect is more pronounced in tool (A) due to the higher tensile strain levels in the direction
of stretch directly affecting the strains in the orthogonal direction. By considering the resultant
moment in each axis of the sheet independently, an analytical method was devised to give an
approximation of the springback profile. Overall the analytical data correlates well with both
experimental and Finite Element (FE) results.
Integrated Tube and Double Sheet Hydroforming Technology - Optimised Process for the Production of a Complex Part
Authors: Geiger Manfred , Merklein Marion , Cojutti Massimo
Published: March 2009

The possibility to produce lightweight components with a complex geometry enhanced,
in the last decades, the industrial application of the tube hydroforming and, more recently and
restricted to specific industrial fields, of the sheet hydroforming technology. The integration in one
tool of a tube and a double sheet hydroforming process represents an innovative technology which
further emphasises the advantages offered by hydroforming in terms of costs reduction and
complexity of the manufactured part. This paper describes the design and the construction of a
complex hollow part resulting from the simultaneous hydroforming of two sheets and a tubular
component in one tool. The focus is set in particular on the optimisation of the joining zone between
tube and sheet pair, whose geometry allows a “metallic” sealing of the gap between the sheets and
the tube, i.e. without using sealing components. The contact between tube and sheet pair allows the
transmission of the axial force used to support the bulging of the tube to the sheet blanks, thus
increasing their draw-in in the die and, consequently, avoiding the occurrence of tearing on the part.
The paper describes the optimisation of different process parameters like the shape and the
dimension of the blanks, their initial positioning in the tool, the value of the axial force applied to
the tubular component and the blankholder force during the preforming and the calibrating stages.
Experimental and Numerical Analysis of Forming Limits in CNC Incremental Sheet Forming
Authors: Bambach Markus , Todorova M. , Hirt Gerhard
Published: March 2009

Asymmetric incremental sheet forming (AISF) is a relatively new manufacturing process
for the production of low volumes of sheet metal parts. Forming is accomplished by the CNC
controlled movements of a simple ball-headed tool that follows a 3D trajectory to gradually shape
the sheet metal blank. Due to the local plastic deformation under the tool, there is almost no draw-in
from the flange region to avoid thinning in the forming zone. As a consequence, sheet thinning
limits the amount of bearable deformation, and thus the range of possible applications. Much
attention has been given to the maximum strains that can be attained in AISF. Several authors have
found that the forming limits are considerably higher than those obtained using a Nakazima test and
that the forming limit curve is approximately a straight line (mostly having a slope of -1) in the
stretching region of the FLD. Based on these findings they conclude that the “conventional”
forming limit curves cannot be used for AISF and propose dedicated tests to record forming limit
diagrams for AISF. Up to now, there is no standardised test and no evaluation procedure for the
determination of FLCs for AISF. In the present paper, we start with an analysis of the range of
strain states and strain paths that are covered by the various tests that can be found in the literature.
This is accomplished by means of on-line deformation measurements using a stereovision system.
From these measurements, necking and fracture limits are derived. It is found that the fracture limits
can be described consistently by a straight line with negative slope. The necking limits seem to be
highly dependent on the test shapes and forming parameters. It is concluded that standardisation in
both testing conditions and the evaluation procedures is necessary, and that a forming limit curve
does not seem to be an appropriate tool to predict the feasibility of a given part design.
Stable Incremental Deformation of a Strip to High Strain
Authors: Hadoush A. , van den Boogaard Ton , Huétink J.
Published: March 2009

This paper presents the effect of combined stretching and bending on the achieved strain in
incremental sheet forming ISF. A simple two dimensional model of strip undergoing stretching and
travelling three point bending in cyclic form is used. The numerical model presents the effect of the
ratio of stretching velocity to roll-set speed on the achieved strain and its distribution.
Finite Element Analysis of Self-Pierce Riveted Joints
Authors: He Xiao Cong , Pearson Ian , Young Ken W.
Published: March 2009

Self-pierce riveting (SPR) is a sheet material joining technique which is suitable for
joining dissimilar materials, as well as coated and pre-painted materials. Published work relating to
finite element analysis of SPR joints is reviewed in this paper, in terms of process, static strength,
fatigue strength, vibration characteristics and assembly dimensional prediction of the SPR joints. A
few important numerical issues are discussed, including material modelling, meshing procedure,
failure criteria and friction between substrates and between rivet and substrate. It is concluded that
the finite element analysis of SPR joints will help future applications of SPR by allowing system
parameters to be selected to give as large a process window as possible for successful joint
manufacture. This will allow many tests to be simulated that would currently take too long to
perform or be prohibitively expensive in practice, such as modifications to rivet geometry, die
geometry or material properties. The main goal of the paper is to review recent progress in finite
element analysis of SPR joints and to provide a basis for further research.
Study of New Joining Technique: Flat Clinching
Authors: Borsellino C. , Di Bella G. , Ruisi V.F.
Published: March 2009

In this paper a development of clinching, called flat clinching, is presented. After a press
clinching process, the joined sheets have been deformed by a punch with a lower diameter against a
flat die. In this way a new configuration is created with a geometry that has no discontinuity on the
external surface (bottom). A new procedure has also been tested: the second step is perfomed by
pressing the joint between two flat dies. This second case has revealed itself to be very
effective.Tensile tests have been done to compare the joints strength among the various joining
techniques. Moreover some joints have been cut to analyse the changing of the contact line shape
and how its characteristics parameters can influence the bonding performances.
To optimise the process a finite element analysis has been performed.
Aesthetic Diode Laser Welding of Stainless Steel
Authors: Quadrini Fabrizio , Santo Loredana , Trovalusci Federica
Published: March 2009

In the present study the use of diode laser for stainless steel aesthetic welding is
considered. In fact the surface smoothness of the weld bead, attributed to the mode stability of the
laser system, suggests its application for aesthetic weld joint. The aims of this work were to: define
a process map, based on an aesthetic criterion; mechanically characterize the weld joints (by Vickers
micro-hardness and tensile test); analyse the surface of the specimens in terms of roughness.
Moreover, gas tungsten-arc (TIG) weld joints were carried out and analogously tested to make a
comparison with the diode laser results.
Good aesthetic butt joints were obtained with diode laser welding. The same results were found
working with constant power speed ratio (i.e. constant fluence).
Comparison between TIG and Laser Beam Welding (LBW), showed no significant difference in
roughness, while ultimate tensile load was higher for TIG welding. The differences in joint strength
depend on the different cross-sectional area and on the extension and microstructure of the base
metal, heat-affected zone and melted zone. However, diode laser technology allows to obtain
smaller bead size.
The Occurrence of Humping in Welding with Highest Beam Qualities
Authors: Thomy Claus , Seefeld Thomas , Vollertsen Frank
Published: March 2009

The availability of lasers with highest beam qualities at laser powers of 1 kW (such as
single-mode fibre laser, which nowadays come close to the theoretical limits) provides a unique tool
to investigate welding process phenomena in a wide range of potential applications from welding
with penetrations of some 50 "m to penetrations of some mm. Thus covering the field of micro
welding as well as of macro welding, scalability of welding processes as well as size effects
associated with the underlying physical phenomena may be of significance.
In this paper, the humping effect will be given a closer look, as this periodic melt pool instability
is an important limitation to possible welding speeds both in the micro and the macro range. Based
on experimental investigations with a single-mode fibre laser (YLR-1000, laser power 1 kW,
BPP < 0.4 mm*mrad), a model based on a modification of Rayleigh’s considerations on the stability
of an inviscid incompressible fluid which is freely suspended in space and maintained only by
surface tension is developed and discussed. It is shown that, within the scope of the investigations,
humping to a large extent can be explained by Rayleigh’s theory, permitting to neglect the influence
of three-dimensional melt flow.
A Methodology for Real Time Surface Strain Measurement for Stamping Through Non-Contact Optical Strain Measurement System
Authors: Kalyanasundaram Shankar , Compston Paul , Gresham Joel
Published: March 2009

The quality of stamp formed parts depends on a number of variables. Numerical studies
based on finite element analysis can provide evolution of strain during forming and correlate with
different failures of the formed parts. This study presents a methodology of capturing the evolution
of strain during forming through a photogrammetric method. An open die was used to monitor the
strain evolution of domed parts. The forming characteristic of a fibre-metal laminate system was
compared to a monolithic aluminum alloy to elucidate the differences in the strain evolution during
forming. It was found that the two materials exhibited different strain evolution during forming and
this affected the failure behavior of the formed parts.
Improvement of Fatigue Behaviour of High Strength Aluminium Alloys by Fluidized Bed Peening (FBP)
Authors: Barletta M. , Lambiase F. , Tagliaferri Vincenzo
Published: March 2009

This paper deals with a definition of a relatively novel technique to improve the fatigue
behavior of high strength aluminum alloys, namely, Fluidized Bed Peening (FBP). Fatigue samples
made from AA 6082 T6 alloy were chosen according to ASTM regulation about rotating bending
fatigue test and, subsequently, treated by varying FBP operational parameters and fatigue testing
conditions. First, a full factorial experimental plan was performed to assess the trend of number of
cycles to rupture of fatigue samples varying among several experimental levels the factors peening
time and maximum amplitude of alternating stress applied to fatigue samples during rotating
bending fatigue tests. Second, design of experiment (DOE) technique was used to analyze the
influence of FBP operational parameters on fatigue life of AA 6082 T6 alloy. Finally, ruptures of
FB treated samples and untreated samples were discussed in order to evaluate the influence of
operational parameters on the effectiveness of FBP process and to understand the leading process
mechanisms. At any rate, the fatigue behavior of processed components was found to be
significantly improved, thereby proving the suitability of FBP process as alternative mechanical
technique to enhance fatigue life of components made from high strength aluminum alloy.
Structure Analyses of the Wings of Anotogaster Sieboldii and Hybris Subjacens
Authors: Machida Kenji , Oikawa Tomoaki
Published: March 2009

The wings of a dragonfly have many complicated structures. The configuration of the
costal vein of the wings of a dragonfly is different from them of other insects. So, we paid attention
to the configuration of the costal vein of the wings in this study. In order to know the functions and
structures of the wings of a dragonfly, several 3-D models of the wing of Anotogaster Sieboldii
were created, and calculated with the 3-D finite element method. In addition, we created a 3-D
model of the wing of Hybris Subjacens which has the configuration of original wing, and compared
the models of Anotogaster Sieboldii and Hybris Subjacens. As a result, it was clarified that the arch
configuration of the costal vein controls the bending and the torsion of the wings.
Thermo-Mechanical Fatigue of the Nickel–Base Superalloy Nimonic 90
Authors: Marchionni M. , Klingelhöffer Hellmuth , Kühn Hans Joachim , Ranucci T. , Matzak Kathrin
Published: March 2009

The thermo-mechanical fatigue (TMF) behaviour of the Nimonic 90 Nickel base
superalloy has been investigated within two laboratories. In-phase-tests (IP) where the maximum
mechanical strain occurs at the maximum temperature (850°C), and 180°-out-of-phase-tests (180°
OP) where the maximum mechanical strain coincides with the minimum temperature (400°C) have
been applied. All tests were carried out at varying mechanical strain ranges with a constant strain
ratio of Rε = - 1. A temperature rate of 5 K/s was used throughout the whole cycle without any
additional cooling system during decreasing temperature. The fatigue life of 180° OP tests is longer
compared to identical IP tests. The stress / mechanical strain hysteresis loops are completely
different and some characteristic values are compared to each other. The fracture surfaces observed
show that fatigue crack (or cracks) starts on the external surface and propagates inwards. The
fractures of 180° OP tests are transgranular showing the presence of fatigue striations, while the
fractures of IP tests are mixed transgranular and intergranular with no fatigue striations.
Damage Assessment of Steel Bridge Members by Fatigue Vulnerability Considering Corrosion and Traffic Variation with Time
Authors: Kim Hyo Jin , Kim Dong Jo , Lee Hyeong Cheol , Lee Sang Ho
Published: March 2009

The fatigue vulnerability estimation method including the effects induced by the corrosion
rate and the traffic variation with time has been proposed to evaluate the reduction of fatigue strength
in steel bridge members. A fatigue limit state function considering corrosion and traffic variation is
established to determine whether the steel bridge members have been damaged by both corrosion and
fatigue or not. Monte-Carlo simulation is used for reliability analysis which provides the data used to
obtain fatigue vulnerability curves. The results show that the damage accumulation induced by fatigue
in steel bridges could be assessed by fatigue vulnerability curve considering influences of corrosion
and traffic variation.
Comparison of DBEM and FEM Crack Path Predictions with Experimental Findings for a SEN-Specimen under Anti-Plane Shear Loading
Authors: Citarella Roberto G. , Buchholz Friedrich G.
Published: March 2009

In this paper detailed results of computational 3D fatigue crack growth simulations will
be presented. The simulations for the crack path assessment are based on the DBEM code BEASY,
and the FEM code ADAPCRACK 3D. The specimen under investigation is a SEN-specimen
subject to pure anti-plane or out-of-plane four-point shear loading. The computational 3D fracture
analyses deliver variable mixed mode II and III conditions along the crack front. Special interest is
taken in this mode coupling effect to be found in stress intensity factor (SIF) results along the crack
front. Further interest is taken in a 3D effect which is effective in particular at and adjacent to the
two crack front corner points, that is where the crack front intersects the two free side surfaces of
the specimen. Exactly at these crack front corner points fatigue crack growth initiates in the
experimental laboratory test specimens, and develops into two separate anti-symmetric cracks with
complex shapes, somehow similar to bird wings. The computational DBEM results are found to be
in good agreement with these experimental findings and with FEM results previously obtained.
Consequently, also for this new case, with complex 3D crack growth behaviour of two cracks, the
functionality of the proposed DBEM and FEM approaches can be stated.
Experiment Studies on Fracture Energy of Cement Paste and Mortar
Authors: Xu Shi Lang , Zhu Yu
Published: March 2009

As cement-based composite, concrete can be properly represented by three phases in
microstructure: cement paste, aggregate as well as interfacial transition zone between them. As the
matrix compositions of concrete, fracture properties of cement paste and mortar have great
influence on fracture performance of concrete, and fracture energy is an important parameter for
concrete non-linear fracture mechanics research. Therefore, three-point bending beams of cement
paste and mortar with different sizes and strengths were tested. A complete load-deflection (P-δ)
curve was directly obtained, and a fit was made for the tail of the P-δ curve using power and
exponential function, respectively. And then the fitting results of the two function were compared. It
was found that with the increase of specimen size the influence of tail curve on fracture energy is
decrease，and considering the influence of tail curve, fracture energy of cement paste and mortar are
size-independent. The discussion on the obtained results was made.
The Use of the Singular Elastic Peak Stress Evaluated by FE Analyses for Fatigue Strength Assessment of Welded Joints
Authors: Atzori Bruno , Lazzarin Paolo , Meneghetti Giovanni
Published: March 2009

The paper presents a simplified version of the Notch Stress Intensity Factor (NSIF)
approach useful for fatigue strength assessments of welded joints. The evaluation of the NSIF from
a numerical analysis of the local stress field usually needs very refined meshes and then large
computational effort. A relationship is proposed here to estimate the Notch Stress Intensity Factor
from finite element analyses carried out by using a mesh pattern with a constant element size. The
main advantage of the presented relationship is that only the elastic peak stress numerically
evaluated at the V-notch tip is necessary to estimate the NSIF instead of the whole stress-distance
set of data (that is why the method has been called Peak Stress Method, i.e. PSM). An application of
the PSM to fatigue strength assessment of fillet welded joints made of structural steels and
aluminium alloys under tensile or bending loads is presented. In those joints, only mode I stress
distribution is singular at the weld toe due to the presence of a V-notch angle equal to 135 degrees.
Deformation and Damage Evolution of the Microstructure around Ti-Particles in IF Steel during Tensile Deformation
Authors: León-García Orlando , Petrov Roumen H. , Kestens Leo A.I.
Published: March 2009

The microstructure evolution in the deformation zone around second phase particles of IF
steel sheets subjected to tensile deformation has been investigated in order to correlate it to the
damage at microstructural scale. The experimental set-up consisted of a series of interrupted tensile
tests which were carried out at different tensile deformations up to fracture. The microstructure of
the deformed samples was investigated by EBSD analysis in which the EBSD scans were focused
on the areas containing Ti (C, N) particles of cubical shape. It was found that at tensile strains below
25%, the ferrite matrix exhibited the evolution of slip bands inside specific grains depending on
their crystallographic orientation although no special strain localization around the particles was
observed. After 35% of tensile strain, the strain concentrates around the particles and particle-matrix
decohesion was observed. The lattice rotations of the matrix surrounding the particles as well as the
selective deformation of the grains are analyzed and discussed.
Models for Estimating the Durability of Repeated Impacts
Authors: Dumitru Ion , Marsavina Liviu , Faur Nicolae , Hajdu I.
Published: March 2009

Many components from industry are subjected to repeated impacts, or in some cases
these impacts can appear as additional loads. Repeated impacts define a fatigue phenomenon known
under the name of Impact Fatigue. Because the strain rate changes the material characteristics it is
to expect that the material properties at impact fatigue to be different in regard to those obtained at
non-impact fatigue. First studies at repeated impacts were made at the middle of 19th Century, but
the progress in this field is not as fast as non-impact fatigue, due to experimental difficulties and the
lake of standards for impact fatigue tests. This paper presents a classification of repeated impact
tests, and starting from this a series of parameters used for durability estimation will be analyzed.
The high number of parameters used by different authors creates difficulties in comparison the
different laboratories results. The importance of the shape and dimensions of specimens, and the
stiffness of bearing are highlighted. In order to avoid these influences the authors proposed an
experimental technique, based on testing of Charpy specimens, in similar conditions as single
impact test. The paper presents a series of results obtained for additional impacts overlapped to a
cyclic load.
Stress Intensity Factor for Cracks at the Toe of Welded Joints
Authors: Livieri Paolo , Tovo Roberto
Published: March 2009

This paper proposes a method for evaluation of the Stress Intensity Factors (SIFs) of
embedded cracks lying along the bisector of the welded toe angle. The SIFs are calculated on the
basis of the JV parameter (extension of the J-integral to a sharp V-notch) for a path radius equal to
the crack extension without modelling the crack. The numerical calculations in the paper show the
stability of the proposed method also with course meshes.
Effect of Preformed Angle in Lap Zone on the Failure Procedure of Adhesively Bonded Aluminium Joint
Authors: You Min , Yu Shan , Yu Hai Zhou , Li Zhi , Liu Wen Jun
Published: March 2009

The effect of the preformed deflection angle in the lap zone on the failure mode and the
stresses distribution in the single-lap joint made of the epoxy adhesive and the aluminium adherend
was investigated using elasto-plastic finite element method (FEM) and the experimental method of
the shear strength testing. The failed surfaces were studied with the diagrams of scanning electron
microscopy (SEM). The results from the numerical simulation showed that all the peak stresses in
adhesively bonded single lap joint were decreased first and increased again as the preformed
deflection angle was increased from 00 to 150. The lowest values occurred when the angle was taken
as 100 and its strength is 22.1% higher than that of the standard one as the peak stresses were
decreased and the stress distributed more evenly. The SEM images also show that the failure mode
of the joint was transmitted from the adhesion to the mixed one as the deflection angle increased.
An Evaluation of the Use of Fracture Mechanics Techniques for the Design of Orthotropic Decks
Authors: de Corte Wouter , Van Bogaert Philippe
Published: March 2009

Although the use of fracture mechanics based techniques in the evaluation of fatigue
resistance in civil engineering has expanded steadily, it’s application in the field of orthotropic
bridge decks remains very small. This is remarkable, since especially orthotropic decks have
numerous fatigue prone details, which could benefit from a fracture mechanics based approach, or
alternatively from the hot spot stress method. Currently, all international design guidelines for
orthotropic plated bridge deck are based on a traditional nominal stress S-N approach and Miner’s
Rule, and, although suggested by various in field designers and bridge owners, a fracture mechanics
approach is currently limited to academic research. The paper gives an overview of current practice
in the field, as well as an overview of attempts made academic researchers to apply fracture
mechanics techniques. The available literature suggests that the lack of implementation of fracture
mechanics results from a combination of factors including the lack of experience with these
methods, conservatism, but also the complexity of geometry and loading conditions resulting in
numerous variables. This paper may contribute to the implementation of modern fracture
mechanics based techniques in this field by pointing out the opportunities and warning for the
difficulties.
The Experimental Study on Fracture Characteristic of Rock
Authors: Zhang Guang , Chen Jing Xi , Jiao Wen Yu , Zhang Heng Wei
Published: March 2009

Based on the stress analyses on the surrounding rockmass of underground caverns, the
stress states on the surface and inside the surrounding rockmass are simulated respectively using
biaxial compression tests and truly triaxial compression tests, and the fracture characteristic of rock
and the relation between the angle of rock rupture,θ ,and stress state are studied. According to the
testing results, the stress state condition of different type of rock bursts generating in different
regions of the surrounding rockmass. The research results show that the rock burst of flake-splitting
type takes place around the cavern’s surface under the biaxial compression stress state whereas that
of shearing-dislocation type takes place inside the surrounding rockmass under the stress state of
truly triaxial compression.
Numerical Modeling of Wave Propagation vs. NDT in Multi-Layer Media
Authors: Cho Young Sang
Published: March 2009

A NDT test, spectral analysis of surface wave (SASW) method, is a
relatively new technique for examining the structural integrity of structural members
of building structures. The SASW method has advantages among NDT methods that
it needs an access from only one side of a testing object and can measure the
dispersive characteristics in layered structures. This study is to model the wave
propagation of stress waves in concrete media using a finite element method.
Experiments using the NDT are to be conducted to investigate the wave behavior in
concrete media. This study also evaluates the surface wave velocity of single layer
cement mortar systems using an experimental analysis of the SASW method, and
examines the corresponding results with numerical results. Specimen models were
single-layer cement mortar slab systems.
Anti-Corrosion Performance of Zn-Al Thermal Metal Spraying Method Using Steel Structures
Authors: Lee Sang Hyun , Lee Han Seung , Kyung Je Woon , Kang Chang Soo , Han Man Hae
Published: March 2009

This study performs an electrochemical experiment to quantitatively evaluate the corrosion
resistance performance in a Zn-Al thermal metal spraying method and produces corrosion current
density according to the type of corrosion resistance methods. In the results of the calculation, the
corrosion membrane produced in a Zn-Al thermal metal spraying method showed voltage differences
more than 300 mV and that demonstrated enough corrosion performance with the corrosion resistance
reaction of base materials and proper Zn-Al ratio, such as 50:50. Also, the results exhibited that the
corrosion speed in a Zn-Al thermal metal spraying method was 0.66 time faster than that of the zinc
galvanizing method in the estimation based on the standard of corrosion resistance service years in a
zinc galvanizing method (JIS H 8641).
Improvement of MIC Behavior of Low Alloy Steel with Zn-Rich Epoxy Coating
Authors: Liu Dong , Li Qing Fen , Li Chun Hui , Xue Li Li
Published: March 2009

The microbiological influenced corrosion (MIC) behavior of the low alloy steel with or
without Zn-rich epoxy coating in the sterilized medium and sulfate-reducing bacteria (SRB)
solution was investigated with electrochemical impedance spectroscopy (EIS), scanning electron
microscope (SEM) and X-rays diffraction (XRD). Results show that the bacteria in the marine
environment affect the corrosion behavior of the ship plate steel and the corrosion resistance of
specimen coated with Zn-rich epoxy was improved greatly. The coating protected the test steel
effectively in the microbial environment with the cathodic protection in the earlier period and
physical barrier protection in the later period.
Experimental and Numerical Characterization of a Rail Steel Behavior under Cyclic Contact Stresses
Authors: Mazzù Angelo
Published: March 2009

Wear and rolling contact fatigue interaction in rolling/sliding contact is an important
topic in the research on structural integrity of rails and railway wheels. Wear is in competition with
rolling contact fatigue, as it removes surface material layers, reducing cracks length and hindering
their propagation. Cracks nucleate by accumulation of cyclic unidirectional plastic strain
(ratcheting). In this paper a model for ratcheting assessment is discussed and applied to the UIC
900A steel, after a calibration based on experimental results. The experimental tests allow also a
characterization of the crack formation condition for this material. By this model, a computer
program is developed in order to simulate in a very short time the effect of a large number of load
cycles, providing a tool for predicting crack formation and propagation rates.
How Does Bone Detect Cracks?
Authors: Taylor David , Hazenberg Jan , O'Brien Fergal , Lee T. Clive
Published: March 2009

We conducted work to investigate fatigue cracking and repair in bone, in which we
discovered the mechanism by which bone is able to detect the presence of microscopic cracks and
thus initiate repair processes. This investigation has made use of theoretical and applied fracture
mechanics, in combination with cell biology. It is the first example of a completely-understood
mechanism showing how living cells can respond to mechanical stimuli.