bluuebunny/crossref_metadata_2025 huggingface dataset:
Study on Substrate Temperature Field during its Swing Movement in Miniature HFCVD System
Authors: Zuo Dun Wen , Zeng Dang , Wang Hong Xiang , Lu Wen Zhuang , Wang M.
Published: March 2009

Based on the traditional HFCVD system, a new set of miniature HFCVD diamond
film-deposition system with a swingabe substrate platform has been designed. Simulations of the
substrate temperature field have been done respectively when the platform is still, rotating
continuously, or swinging. The results suggest that when the swing angle is bigger than 100,
uniform temperature field close to that achieved through continuous rotation can be got. So, in this
paper, the crank-rocker mechanism has been used to produce a swingable substrate platform, which
simplifies the traditional structure. And satisfactory temperature field can be achieved. It meets the
requirements of the miniaturization design.
A Finite Element Analysis of Micro/Meso-Scale Machining Considering the Cutting Edge Radius
Authors: Cao Zi Yang , He Ning , Li Liang
Published: March 2009

In order to investigate the effects of cutting edge radius on micro/meso-scale cutting process, the current paper is concerned with a fundamental investigation of the contribution of cutting edge radius to cutting temperature, stress field and size effect by means of two-dimensional finite-element simulation for orthogonal cutting process. The results indicated that cutting edge radius has remarkable effects on cutting temperature and stress field, and the existence of cutting edge radius is one of the main reasons generating size effect. The cutting edge radius affects the micro/meso scale cutting process at smaller uncut chip thickness by altering the effective rake angle and enhancing the plowing effect, affecting the material deformation process, expanding and widening the plastic deformation zone, and causing higher energy dissipation due to increased tool-chip contact length.
Development of Differential Capacitive Displacement Sensor Based on RC Multi-Oscillating Circuit
Authors: Zhou L. , Zhang H.B. , Liu Qiang
Published: March 2009

In order to meet the demands for high precise micro-displacement testing, a differential
capacitive displacement sensor based on RC multi-oscillating circuit was designed. It has two
couples of polar plates, and gets the displacement by testing frequency through the multi-oscillating
circuit. This capacitive sensor has many advantages such as simple structure and testing circuit,
high resolution and good stability.
Assessment of Ground Surface Roughness Based on Computer Vision Technology
Authors: Wu Chun Ya , Liu Xian Li , Wang Y.J. , Wang P. , Liu Yi Zhi
Published: March 2009

Aiming at different ground surfaces of hardened bearing steel GCr15, this paper made
experimental research on assessment method of surface roughness based on computer vision
technology. Firstly, some pre-processing of the ground images should be carried out to eliminate
noise and get more detail information, including image enhancement and median filtering. Then the
method of power spectrum analysis transformed representation of processed image from spatial
domain to frequency domain by adopting two-dimensional Discrete Fourier Transform. Gaining the
mean power spectrum named E and its corresponding radius r, we made efforts to seek the direction
in which the arithmetic average surface roughness Ra varied according to E and r. After that the
variation rule can be regarded as an assessment basis of ground surface roughness.
Optimization Algorithm for Automated Assembly of Circular Parts
Authors: Jiang Feng , Li Jian Feng , Li Fang Yi
Published: March 2009

Design for assembly (DFA) has proved its success in manufacturing to face the market
challenge. But the assembly process parameters were rarely concerned in the design for assembly.
Aimed at this problem, an algorithm for design for automated assembly of circular parts was
proposed. This algorithm can help designer to select the optimal process parameters, such as
dimension tolerance of mating parts, location precision of assembly device and so on, subject to
budgetary constraints. Finally a case is employed to explain the optimal course.
Prediction Models and Generalization Performance Study in Electrical Discharge Machining
Authors: Gao Qing , Zhang Qin He , Su Shu Peng , Zhang Jian Hua , Ge Rong Yu
Published: March 2009

In the past decade, artificial neural network(ANN) has been applied in Electrical
discharge machining(EDM). However, most of them only discuss parameter prediction or
optimization result, few tell how to improve generalization performance. In this study, machining
process models have been established based on different training algorithms of ANN, namely
Levenberg-Marquardt algorithm (LM), Resilient algorithm (RP), Scaled Conjugate Gradient
algorithm (SCG) and Quasi-Newton algorithm(BFGS). All models have been trained by same
experimental data, checked by another group data, their generalization performance are compared.
Take LM as the example, some main factors that may influence generalization performance are
discussed.
Optimization of Laser Peening Parameters Using Taguchi Method
Authors: Sun Yue Qing , Zhou Jian Zhong , Chen Yi Bin , Huang Shu
Published: March 2009

Using Taguchi method to optimize the critical parameters of laser peening (LP) is
presented firstly. The objective of the study is to assess the impact of laser parameters on the laser
peen strengthening for the 6061-T6 aluminum alloy and optimize the process parameters to achieve
higher surface residual compressive stress. In order to reduce the process cost and time, the finite
element method was applied to simulate the LP process. The Taguchi method is used to formulate
the experimental layout and establish the order of predominance among the identified critical
parameters, and predict the optimal setting for each process parameter. The results show that three
parameters related to the magnitude of compressive residual stress imply different effects. Laser
shot diameter ranks first, followed by pulse width and laser power in terms of their effects on the
magnitude of compressive residual stress. The best combination of levels is given by the levels (3, 3,
2). The optimal result was confirmed with a superior ultimate surface residual compressive stress of
125MP.
Frequency Spectrum Analysis on Cutting Forces in Cutting Process
Authors: Fan N. , Guo Pei Quan , Chi Xian , Gao Z.H.
Published: March 2009

Cutting tool wear has relation with the cutting forces. By way of signal processing, the power spectrums of cutting forces in different tool wear stages are analyzed in the present paper. It is proved that several characteristic frequencies exist within a wide frequency range during the cutting process as long as cutting process parameters keep constant. The power value of the characteristic frequency increase with the increase of tool wear. Thus, the tool wear could be predicted by the changes of characteristic frequencies and their power values.
A New and High Precision Measurement Method of Spindle Rotation Induced Error and its Performance Research
Authors: Du Z.C. , Zhang P. , Yang Jian Guo , Hong M.S.
Published: March 2009

The accuracy of spindle rotation is one of the most important precision indexes of CNC
machine tools. And the spindle rotation induced error is one of the main influence factors of cutting
accuracy. It will greatly affect the shape precision and surface roughness of workpiece. A new
measurement method of the spindle radial rotation induced error is proposed using the cross grid
encoder. The Spindle rotation induced error of machining center is analyzed in frequency domain
and time-frequency domain separately to comparably study the measurement results by KGM 182
grid encoder and Double ball bar. The results indicate that the performance of the cross grid
encoder test for measuring the CNC machine tool motion error is better than that of the Double ball
bar, especially in the details of motion errors because of its unique characteristics. A wavelet packet
algorithm is developed to analyze the singularity of signal. On machine measuring experiment has
been carried out on a new Cincinnati 750 Arrow II vertical machining center. The measuring
experiment result shows that the spindle radial rotation induced error of the machining center is
about 0.6 μm and the cycle time is every rotation time.
Estimate of Tool Wear in Milling Operation Based on “Differential” Wear Rate Model
Authors: Xie L.J. , Zheng D. , Schmidt C. , Schmidt J.
Published: March 2009

Many research show that in metal cutting process wear rate is dependent on the cutting
process variables such as temperature at tool face, contact pressure (normal stress) and relative
sliding velocity at tool/chip and tool/work interface; their relationship is described by “differential”
wear rate model. Based on this “differential” wear rate model, a method to estimate tool wear in
milling operation is proposed and the cutting process variables are predicted by performing chip
formation analysis with FEM code ABAQUS/Explicit and heat transfer analysis with
ABAQUS/Standard. The implementation is exemplified by estimating tool wear of carbide tools in
milling of Ck45 work. Both progressive flank wear and crater wear profile are estimated.
The Precise Design and Machining of Formed Milling Cutters Profile Based on Feature Modeling
Authors: Cheng W. , Liang P. , Bu Yun Feng
Published: March 2009

When using the formed milling cutter to machine workpiece, the formed parts are cut by
the milling with formed shape, so forms correspond to workpiece outline. In the 3D design
software--SolidWorks, the relation of position of the workpiece profile and the milling each other is
simulated. This project uses the function of 3D-shape of software to complete the 3D-entity-design
of formed milling cutter profile and the drawing of rake face, thus designing the rake face profile
directly, with the results of a great improvement on the design and machining quality and
effectiveness.
Material Constitutive Model of 2Cr13 for FEA of Chip Formation Process
Authors: Li L. , Xie L.J. , Wang Xin Bing , Wang L. , Xie J. , Yang H.J.
Published: March 2009

The prediction accuracy of the simulation of cutting process is related with the
description of the nonlinear behavior of material at extremely high strain, strain rate and
temperature in machining. In this paper, an integral Johnson-Cook model is presented to
characterize the mechanical behavior of work materials in machining, and the parameters in the
model are determined by fitting the data from both quasi-static compression and cutting tests. Then
the material equation of 2Cr13 stainless steel is derived with this method and used in the finite
element model of orthogonal cutting with carbide tools. At last, the simulation result is verified with
experimental data.
On-Line Error Measurement Based on CCD in Quick-Point Grinding of Curve Parts
Authors: Luo Yu Mei , Hu De Jin
Published: March 2009

This paper deals with an on-line mismachining error measurement for curve grinding
based on digital image processing. Using CCD camera, the contour of the workpiece’s finished
surface is captured and the image is preprocessed for denoising and edge detecting. The worktable
is guided by the image of the finished workpiece to follow the path of the finished contour and then
the real curve of the finished workpiece is measured by fitting a curve according to the moving path
of the worktable. Finally, the machining error is obtained by comparing the measured curve with
the theoretical curve of the workpiece. This method is applied to a CNC curve grinding machine
MD9040. A measurement experiment is given. The experiment results show that the measurement
method offers high detection precision and can be used in wide fields, especially for measuring the
parts with complex curve.
Development of Surface Image Scanning Device Measurement Head Mechanism Based on AFM
Authors: Zhou L. , Zhang H.B. , Liu Qiang
Published: March 2009

For the measurement of ultra smooth surface topography, a surface image scanning
device measurement head mechanism based on the principle of atomic force microscope (AFM)
was designed. It uses coarse adjustment, semi-delicate adjustment, delicate adjustment triple-stage
adjustment mechanism, and tests the atomic force between the sample and the probe by using laser
generator, position sensitive detector (PSD), cantilever and probe. This mechanism has high setting
accuracy and resetting accuracy, combined with two-dimension movable table, can scan the surface
topography of samples.
Adaptive Quadrangular Segmentation of Triangle Meshes
Authors: Lv Han Ming , Xiu Shu Dong , Wang Yang
Published: March 2009

A heuristic approach was presented to automatically partition a triangle meshes into a
coarse quadrangular segmentation. The triangle mesh was firstly partitioned into a polygonal
segmentation which will further be split into triangular and quadrangular patches. At last, the
quadrangular segmentation was obtained by eliminating triangular patches according to their
topological relations. The final segmentation consisted of pure-quadrangular patches with
appropriate sizes according to the model’s geometric characteristics, and the features of input model
were well captured. Experimental results showed that the algorithm was efficient and effective.
Simulation Study on Spool Edge’s Round Angle Effects on Spool Valve Orifice Discharge Characteristic
Authors: Pan Xu Dong , Wang Guang Lin , Zhang L.
Published: March 2009

This paper deals with the effect on orifice discharge characteristic by the round angle of
electro-hydraulic servo valve spool metering edge. The machining method of spool metering edge
can cause micro round angle on the edge. This paper firstly provides 3D geometry model and
computational grids of spool valve where the round angle’s range is 0-10μm and orifice opening is
0-40μm. Secondly calculates the flow rate of the orifice on the constant differential pressure
circumstances. The numerical analysis is performed by using the commercial code ‘‘Fluent’’, and
the numerical results show the complete flow field inside the valve. The analysis result is to obtain
the influence of round angle on discharge characteristic, quantitatively. An experimental result is
used in this paper to evaluate and validate the numerical analysis of the valve. The aim of this
analysis is to provide a designation reference of the spool valves which are important parts of servo
valve.
Dynamic Stress Intensity Factor with Griffith – II Type Crack in Vibratory Machining and its Influence on Chip Formation
Authors: Gu Li Zhi , Lee T.
Published: March 2009

Reviewed the achievements and advances in the vibratory metal machining, analyzed the
features and mechanics in microstructure with SEM. The dynamic stress intensity factor is derived
on the basis of fracture mechanics and stress-wave theory with the Griffith- II type sliding-open
crack.. Comparison between the vibratory machining and the conventional machining has been
made with brass on lathe CW6150B, with computer controlled piezoelectric ceramic micro-drive
system and cutting forces and surface texture of the specimen were observed. The dynamic stress
intensity factor was discussed and it was found that the value of dynamic stress intensity factor may
be high with response to the Heaviside impulsive loading, indicating the reason why vibratory
machining has better comprehensive results than the conventional one does.
Applications of Power Ultrasonics in Engineering
Authors: Lucas Margaret , Cardoni Andrea , McCulloch E. , Hunter G. , MacBeath Alan
Published: March 2009

Applications of power ultrasonics in engineering are growing and now encompass a wide
variety of industrial processes and medical procedures. In the field of power ultrasonics, ultrasonic
vibrations are used to effect a physical change in a medium. However, the mechanism by which a
process can benefit from power ultrasonics is not common for all applications and can include one
or more of such diverse mechanisms as acoustic cavitation, heating, microfracture, surface agitation
and chemical reactions. This paper presents two applications of power ultrasonics involving some of
these different characteristics by concentrating on two case studies involving material failure
(ultrasonic cutting) and acoustic cavitation (bacterial inactivation).
Experimental-Numerical Analysis of the Indentation-Based Damage Characterization Methodology
Authors: Tasan C.C. , Hoefnagels J.P.M. , Louws L.C.N. , Geers M.G.D.
Published: March 2009

The introduction of advanced high strength steels, e.g., into the automotive industry
initiated a huge interest in analyzing and understanding ductile fracture of sheet metals to greater
details. This demands for the development of experimental methodologies that provide microvoid
evolution parameters, which also serve as crucial input parameters for advanced forming simulation
that can predict damage evolution. Therefore, this work scrutinizes the reliability and applicability
of an increasingly popular damage characterization methodology, in which microindentation tests
are carried out to measure hardness and elastic modulus degradation as a function of accumulated
strain, relating this degradation to damage evolution. To accomplish this goal, this methodology is
applied to several different sheet metals of different formability (an interstitial-free steel, a dual
phase steel, an aluminum-magnesium-silicon alloy and a ferritic stainless steel). To analyze and
verify the results of indentation based methodology, damage evolution in these metals is monitored
also via different experimental techniques, i.e. scanning electron microscopy, micro-ct tomography
and sensitive density measurement. Moreover, finite element simulations are carried out to
understand the effect of void accumulation in the degradation of hardness and elastic modulus. In
the case of using the hardness as a damage probe, the degradation due to damage is always coupled
to other effects (strain hardening, grain shape change, texture development) causing an increase in
the obtained hardness value for all of the sheet metals tested, thereby complete obscuring any
degradation of the hardness due to damage. In the case of elastic modulus, all the sheet metals tend
to pile-up upon indentation when they are severely deformed, leading to large systematic errors in
the Oliver-Pharr methodology based modulus determination, whereas the elastic modulus is also
intrinsically altered by the grain shape change and texture development seen for increasing
deformation. Therefore, it can only be concluded that, contrary to the published results in the
literature, neither the hardness degradation nor the elastic modulus degradation can be used as a
precise probe for damage accumulation, at least when the indentation based methodology is carried
out in the originally-proposed manner that is commonly used in the literature.
Impact Compressive Failure of a Unidirectional Carbon/Epoxy Composite: Effect of Loading Directions
Authors: Yokoyama Takashi , Nakai Kenji
Published: March 2009

The impact compressive failure behaviour of a unidirectional T700/2521 carbon/epoxy
composite in three principal material directions is investigated in the conventional split Hopkinson
pressure bar. Two different types of specimens with square cross sections are machined from the
composite in the plane of the laminate. The uniaxial compressive stress-strain curves up to failure at
quasi-static and intermediate strain rates are measured on an Instron testing machine. It is
demonstrated that the ultimate compressive strength (or maximum stress) increases slightly, while
the ultimate compressive strain (or failure strain) decreases marginally with strain rate in the range
of 10-3 to 103/s in all three directions. Dominant failure mechanisms are found to significantly vary
with strain rate and loading directions along three principal material axes.
Factors Influencing the Suitability of Thermal Methods for Stress Analysis of NiTi Shape Memory Alloys
Authors: Eaton-Evans James , Dulieu-Barton Janice M. , Little Edward G. , Brown Ian A.
Published: March 2009

The material assumptions made to facilitate Thermoelastic Stress Analysis (TSA) are
linear elasticity, material homogeneity and isotropy, and mechanical properties that are independent
of temperature. The unusual shape memory and superelastic properties of near equiatomic NiTi
alloys complicate the application of any experimental stress analysis technique, and in the case of
TSA, make these assumptions invalid. This paper describes a detailed analysis conducted to
characterise the material properties of NiTi shape memory alloys and to identify loading conditions
suitable for quantitative stress analysis using TSA. The mechanical behaviour of the material in
three distinct regions is considered and the suitability of each region for TSA is discussed. It is
shown that the thermoelastic response is dependent on the mean stress when tested at room
temperature in the pre-martensitic phase, due the presence of an intermediate R-phase. Theoretical
calculations are used to confirm that this effect is related to the high temperature dependence of the
material’s Young’s modulus.
Streaming Birefringence - A Step Forward
Authors: Spalton T. , Tomlinson Rachel A , Garrard A.E. , Beck S.B.M.
Published: March 2009

An investigation into three dimensional fluid flow has been conducted which combines
the use of Computational Fluid Dynamics (CFD) simulations with the experimental phenomenon of
Streaming Birefringence. A versatile flow channel was designed and built for use in conjunction
with a circular polariscope. The experimental liquid used was an aqueous solution of a dye,
commercially known as Milling Yellow NGS with the addition of Sodium Chloride. To extract the
flow fields, six image phase stepping photoelasticity was used over backward and forward steps,
and flows around a cylinder, and full-field fringe data were obtained. This method needs laminar
flow regimes and the Reynolds number of the flow was around 10. To allow direct comparisons of
the CFD solutions with the optical results, a macro (UDF) was written to interpret the flow field
results from a (FLUENT6) CFD simulation. This integrated the shear stresses across the flow field
and banded the results into fringes. A good correlation between the simulated fringes and the shearstrain
rate was obtained from these observations.
Deformation Evaluation of Solder Ball Joints by Electromotive Force
Authors: Kumazawa T. , Kaminishi K.
Published: March 2009

Deformation measurements with a thermocouple were applied in a deformation test of
solder joints. The thermocouple is effectively combined with a conventional testing machine. The
lead–solder and non–lead solder joints were pulled and sheared. The load-displacement and
electromotive force (Emf)–displacement curves can be continuously derived from the signals of a
load cell and the thermocouple. The Emfs in tension were compared with that in shear. The
maximum Emf value in tension was larger than the emf value in shear, which meant in weakness of
the solder joint in shear. Fracture occurred at the interface between the copper layer pad and solder,
and the obtained Emf is closely related to fracture at the interface. The maximum Emf value in the
non-lead solder was smaller than the Emf value in the lead–solder.
Influence of the Heat-Treatment Process on the Mechanical Properties and Dimensions of Multi-Filamentary Composite Nb3 Sn Superconducting Wires
Authors: Harvey D.A. , Fellows N.A. , Durodola J.F. , Twin Andrew
Published: March 2009

The levels of stress and strain experienced by the windings of a superconducting magnet during its manufacture and operation are dependent on the mechanical properties of the multifilamentary composite wire that the windings are comprised of. It is also influenced by the change in dimensions of the wire during the reaction heat-treatment stage of the manufacturing process. Using specimens cut from a spool of 1.5mm diameter niobium tin type superconducting wire, the influence of the heat-treatment process on the mechanical properties and dimensions have been investigated. The heat-treatment was carried out in an inert atmosphere using apparatus specially developed for the purpose. For heat-treatment durations up to that required to complete the reaction of the niobium filaments into Nb3Sn, the volume and diameter of the wires increased with increasing heat-treatment duration. The maximum increase was 2% and 0.8% respectively. The length of the wires decreased slightly for the shorter heat-treatments, but increased up to 0.33% for the longer ones. The mechanical properties were significantly different for specimens that had no heat-treatment compared to those that had only a short heat-treatment, one that was insufficient to convert much of the niobium into Nb3Sn. Before heat-treatment the bronze within the wires is in a work-hardened state, but gets annealed during the heat-treatment and this is probably the major cause of the change in mechanical properties. Apart from becoming more brittle, the mechanical properties do not change much for different durations of heat-treatment. This is quite remarkable considering that the composition changes dramatically with the length of the heat-treatment.
Thermoelastic Stress Analysis of Composite Finger Joints
Authors: Boyd S.W. , Dulieu-Barton Janice M. , Rumsey L.
Published: March 2009

The marine industry at present employs the use of aluminium extrusions in the construction of decks and superstructures that could be replaced with pultruded glass reinforced plastic (GRP) profiles. The length of the pultruded section is limited and therefore, efficient and economic jointing techniques must be developed that can withstand the loads applied to ship structures. This paper evaluates a novel means of adhesively bonded connection for GRP structures known as a finger joint. Various joint geometries are examined, load displacement behaviour is established and Thermoelastic Stress Analysis (TSA) is used to provide the full field stress distribution over the joint. The results of the TSA are compared with the load displacement behaviour. It is shown that by increasing fingertip angle there is a decrease in load carrying capacity, a decrease in shear stress and an increase in stress concentration factor at the finger joint tip.
Knowledge of Service Loads – The Key to Structural Integrity
Authors: Smith Roderick A.
Published: March 2009

This paper emphasises the importance of the knowledge of service loads to both the initial design process and the maintenance of structural integrity during the lifetime of engineering components and structures. Three case studies are presented. All involve accidents which caused major loss of life: the Hillsborough Stadium disaster in Britain, the German ICE train crash at Eschede and the China Airlines disaster off Taiwan.
Transition Saddle-Cylinder Shape of Thin Unsymmetric [0/90] Square Plates under Hygrothermal Loads: Fringe Projection Method and Variational Approach
Authors: Gigliotti M. , Jacquemin Frédéric , Molimard J. , Vautrin A.
Published: March 2009

The deformation of free laminated plates subjected to transient hygrothermal loading is simulated by using a semi-analytical non linear model (variational method). A full-field experimental technique, the fringe projection method, has been developed to measure out-of-plane displacements throughout the deformation process. The experimental approach based on a full-field optical method is shown to be suited to capturing the complex behaviour of plates submitted to large hygrothermal loads, where geometrical nonlinearities should be taken into account.
Rolling Bearings Monitoring and Damage Detection Methodology
Authors: Delprete Cristiana , Milanesio Mario , Rosso Carlo
Published: March 2009

Aim of the research was the development of an effective and functional methodology able to monitoring and precociously diagnosing rolling bearings damage during operating conditions. Several experimental tests have been carried on a dedicated test rig. The monitoring methodology has been revealed effective in an early detection of rolling bearings damage, also with the contemporary presence of vibrations from unbalances, plays and misalignments.
A Study on Vibration-Based Damage Detection and Location in an Aircraft Wing Scaled Model
Authors: Trendafilova Irina
Published: March 2009

This study investigates the possibilities for damage detection and location using the vibration response of an aircraft wing. A simplified finite element model of an aircraft wing is used to model its vibration response. The model is subjected to modal analysis- its natural frequencies are estimated and the mode shapes are determined. Two types of damage are considered - localised and distributed. The wing model is divided into a number of volumes. The goal of the study is to investigate the possibility to use the vibration response of an aircraft wing and especially its modal characteristics for the purposes of damage detection. So we’ll be trying to find suitable features, which can be used to detect damage and restrict it to one of the introduced volumes. The sensitivity of the modal frequencies of the model to damage in different locations is studied. Some general trends in the behaviour of these frequencies with change of the damage location are investigated. The utilization of the modal frequencies for detecting damage in a certain part of the wing is discussed
Measurement on Rotating Mechanical Component by Thermoelasticity
Authors: Brustenga G. , Marsili R. , Moretti Michele , Pirisinu J. , Rossi Gian Luca
Published: March 2009

In this paper a new measurement technique to perform thermoelastic stress analysis on rotating mechanical component is proposed. The idea is to use a particular realization of the Dove prism optical system, optimized to work width infrared radiation, able to give a fixed output image of a rotating surface on where a normal thermoelastic measurement system can be applied. The realization of a first prototype of this optical system is described. First results on a test case are illustrated.
On the Stiffness and the Reinforcement Effect of Electrical Resistance Strain Gauges
Authors: Ajovalasit A. , D'Acquisto L. , Fragapane S. , Zuccarello B.
Published: March 2009

The reinforcement effect of a strain gauge installed on low modulus materials can be significant. The increasing use of low modulus materials requires therefore the evaluation of such effect. This paper concerns the relationship between the local reinforcement effect and the strain gauge stiffness. The conclusion is that the gauge stiffness alone does not allow the user a thorough evaluation of the reinforcement effect.
Standard Test for the Evaluation of Optical Strain Measurement Systems
Authors: Patterson E.A. , Whelan Maurice P. , Hack Erwin , Siebert Thorsten , Burguete Richard L. , Saleem Q.
Published: March 2009

The paper describes the work towards a set of standardised tests for the evaluation of the performance of optical systems for measuring strain. In particular, the standardised tests are designed to allow the components of a system to be evaluated both in terms of hardware and software. The intention is to allow designers of optical systems to assess the efficacy of their innovations in instrumentation and algorithms, to assist manufacturers of systems in the quality assurance process, to permit end-users to evaluate system capabilities prior to purchase, and to support both manufacturers and end-users in setting up and fault diagnosis. Two standardised tests are proposed and described of which one is physical, a disc in contact with a half-space, and the other is virtual, a pair of shrinkage-fit thick rings or cylinders.
Innovative Remote Video Monitoring of Railway Track Displacements
Authors: Bowness D. , Lock A.C. , Richards D.J. , Powrie W.
Published: March 2009

This paper reports the initial development and testing of an innovative technique for measuring rail displacements that combines remote video monitoring with particle image velocimetry (PIV). A webcam combined with a small telescope is used to monitor rail movements. Results from a laboratory trial, in which the movements of a hydraulic actuator were monitored, demonstrate that the system can measure the peak-to-peak displacements of the actuator to within 0.1mm from 15m away. Results from a section of railway track near Crewe are also reported.
Stress Analysis and Identification with Full-Field Measurements
Authors: Grédiac M.
Published: March 2009

The wealth of information provided by full-field measurement techniques is very useful in experimental mechanics. Among different possible applications, full-field measurements can be used to identify parameters governing constitutive equations from heterogeneous strain fields. This keynote lecture first describes the different possible uses of such measurements. It then focuses on the virtual fields method which has been proposed to extract constitutive parameters from full-field measurements. Finally, the method is compared with the finite element model updating technique which is usually used for solving such a problem.
Combined Lifting Analysis and Load Test of a Hook Foundation in a GRP Hull
Authors: Quinn S. , Moy S.S.J. , Piggott Keith
Published: March 2009

The combination of simulation and physical testing is powerful. In this case study Finite
Element Analysis (FEA) and a 96 tonne load test were used to prove that the lifting points for a new
semi-rigid inflatable rescue craft met their statutory requirements before full manufacture. The
FEA was used to optimise the detailed design of the lifting points, without the need to test each
different configuration, and the load test was used to prove the final design in practice, before full
manufacture. The FEA showed that the bearing stresses in the Glass Reinforced Polymer (GRP)
hull of the initial design were unacceptable and appropriate design changes were made from further
analysis. However, to suitably risk manage the project a full load test was required to demonstrate
that the revised lifting point details met their statutory requirements, before full manufacture of the
new craft.
Characterization of Material Properties Using an Inverse Method
Authors: Lin Lianshan , Li Haiyan , Fok Alex S.L. , Joyce Mark , Marrow T. James
Published: March 2009

A simple finite-element-based inverse method has been devised with the aim of
characterizing the properties of isotropic but heterogeneous materials under load. The method has
been implemented into the commercial finite element code ABAQUS via its User Material
(UMAT) Subroutine to facilitate the process of material characterization. Verification of the method
has been carried out using simulated examples and the results showed rapid convergence of the
method with good accuracy. The method has also been applied successfully to actual mechanical
testing of graphite which has a porous microstructure and hence inhomogeneous distribution of
material properties.
Stress Analysis in Automobile Components Using Reflexive Photoelasticity Technique
Authors: Smith Neto P. , Palma E.S. , Figueiredo Bicalho V.M.
Published: March 2009

The main objective of this work was to introduce Reflexive Photoelasticity Technique in
qualifying automotive components at Fiat Automoveis S.A in Brazil. Actual stresses were
determined in a simple geometry plate and also in nodes of a body shell of a passenger vehicle by
using reflexive photoelasticity methodology. Initially, tests were performed in welded steel plates
submitted to traction loads. These plates were previously coated with birrefringent plastic material.
External loads were applied through hydraulic MTS actuators. Stress and strain distribution in
welded points neighboring areas using reflexive polariscope were quantitative determined.
Simultaneously, these stress and strains acting on the welded plate were determined using strain
gauges. The results from both experimental techniques (photoelasticity and strain gauges) were
compared with those obtained from a numerical model using finite element method. The results
were correlated and analyzed. Finally, reflexive photoelasticity technique was used to determine the
stresses in nodes of a body shell of a passenger vehicle. Through this analysis it was possible to
determine critical points in the structure with peak stresses.
On the Applicability of the Loading Parameter Φ in Pinned Connections with Relevant Initial Clearance
Authors: Ciavarella M. , Strozzi A. , Baldini A. , Giacopini Matteo , Rivasi S. , Rosi R.
Published: March 2009

In pinned connections, the presence of an initial clearance increases the lug stress
concentration with respect to a neat fit configuration. By employing a recently proposed loading
parameter Φ valid for plane models, the applied load and initial clearance effects on the stress
concentration are normalised for a straight-shanked, round-ended, longitudinally loaded pin-lug
connection of fixed outer to inner radius ratio. Results are obtained with a Mitchell-type, Fourier
series solution and with commercial Finite Elements. The applicability of the loading parameter Φ
to pinned connections with small to relevant initial clearances is explored. Two preliminary design
charts are presented, which quantify the lug stress concentration factor versus the loading parameter
Φ for two lug geometries defined by inner to outer radii ratios of 0.376 and 0.77.
Failure Characterisation of Heavy Tow Braided Composites Using Digital Image Correlation (DIC)
Authors: Fouinneteau M. , Pickett A.K.
Published: March 2009

An extensive test campaign has been conducted to characterise the different failure
modes observed in heavy tow (24k) carbon and glass braided composites. The Digital Image
Correlation (DIC) technique was used to obtain complete strain field measurement of large strains
to failure. Failure in the fibre direction, under tension and compression loading were investigated;
in the tension direction relatively large strains to failure were measured due to tow straightening
damage mechanisms. Another important test is tensile shear loading which can undergo very large
strains to failure due to fibre re-orientations in the loading direction. This latter, so-called
‘scissoring’ mechanism, has been quantified through changes of fibre angle during the complete
loading history. Data gathered from coupon testing was used to characterise a material damage,
with failure, model for the heavy tow braids, using a general composite damage model available in
the explicit Finite Element (FE) code PAM-CRASHTM. Finally, four-point bending tests on braided
carbon and glass composite beams with full field strain measurements to failure was carried out and
used to validate the numerical model. A good agreement between simulation and experimental
results was obtained.
On Non-Linear Dynamics and a Periodic Control Design Applied to the Potential of Membrane Action
Authors: Chavarette Fabio R. , Peruzzi N.J. , Balthazar José Manoel , Hermini H.A.
Published: March 2009

The Fitzhugh-Nagumo (fn) mathematical model characterizes the action potential of the
membrane. The dynamics of the Fitzhugh-Nagumo model have been extensively studied both with
a view to their biological implications and as a test bed for numerical methods, which can be
applied to more complex models. This paper deals with the dynamics in the (FH) model. Here, the
dynamics are analyzed, qualitatively, through the stability diagrams to the action potential of the
membrane. Furthermore, we also analyze quantitatively the problem through the evaluation of
Floquet multipliers. Finally, the nonlinear periodic problem is controlled, based on the Chebyshev
polynomial expansion, the Picard iterative method and on Lyapunov-Floquet transformation (L-F
transformation).
Three-Dimensional Elasticity Solutions for Isotropic and Generally Anisotropic Bodies
Authors: Barber J.R.
Published: March 2009

Classical methods of two-dimensional elasticity can be extended to give an exact
solution of the three-dimensional problem for the beam — i.e. a general solution for the pris-
matic bar loaded on its lateral surfaces, subject only to the restriction that the tractions can
be expanded as power series in the axial coordinate z. A series of sub-problems Pj is defined
by successive partial differentiations with respect to z. For isotropic materials, a recursive al-
gorithm can be used for generating the solution to Pj+1 from that for Pj in the context of
the Papkovich-Neuber solution. For the generally anisotropic material, a similar strategy is
proposed, based on partial integrations of Stroh’s formulation of the two-dimensional problem.
Mechanical Behavior of a Calcium Phosphate Ceramic Bone Graft Used in the Rehabilitation of a C4 Human Vertebra
Authors: Beltrán-Fernández Juan Alfonso , Hernández-Gómez Luis Héctor , Rodríguez-Cañizo R.G. , Urriolagoitia-Calderón G. , Urriolagoitia-Sosa G. , González-Rebatú A. , Dufoo-Olvera M.
Published: March 2009

The main results of a static analysis with a finite element model of the cervical section between C3 – C5 of a human spine are reported. In this case, it is assumed that the element C4 is completely damaged and has to be replaced. Therefore, a bone graft was installed between the anterior side of C3 and C5. Besides, a cervical plate of 55 mm. was fixed at the same side with 4 expansive screws. The resultant stresses caused by compression loads were analyzed and the displacements between the graft and adjacent vertebrae were calculated. Three loading conditions were applied: 80 N, 637.5 N and 6374.5 N. The first one corresponds to the head weight. In the second case, it is assumed that the average patient weight is supported by those vertebrae, while in the last one; the compression load failure is applied on the vertebrae. Results show that displacements were lower than 3 mm between the graft and the adjacent vertebrae. In accordance with the concept of spine stability after Müller [1], the arrangement is a stable one. Another advantage is that no wires are used in this surgical technique. Two more issues should be noticed. There is no risk that the plate may be broken and the geometry of the bone graft allows bone regeneration. These results are on line with those observed in preliminary experimental tests with porcine vertebrae.
Experimental Structural Analysis of Pedestal Mounted Stinger System Turret
Authors: Çelik M.
Published: March 2009

An experimental approach for the solution of the turret stress state and dynamic behavior
has been presented using strain gages and accelerometers on Pedestal Mounted Stinger System. The
critical stress locations were determined by finite element analysis outputs where rosettes are
bonded in order to perform the life profile simulation tests. The fatigue state is determined by cycle
counting methods used in data processing of the turret launcher connection zone. The lowest
disturbing frequency of the turret determined from the operational tests is further investigated by the
experimental modal analysis. Consequently, the servo drive system is operated efficiently after
design modifications applied to the turret.
Assessment and Minimization of the Residual Stress in Dissimilar Laser Welding
Authors: Benyounis Khaled Y. , Olabi Abdul Ghani , Abboud J.H.
Published: March 2009

Establishing the relationship between process parameters and the magnitude of residual stresses is essential to determine the life of welded components. It is the aim of this paper to develop mathematical models to assess residual stresses in the heat-affected zone of dissimilar butt jointed welds of AISI304 and AISI1016. These models determine the effect of process parameters on maximum residual stress. Laser power, travel speed and focal position are the process input parameters. Plates of 3 mm thick of both materials were laser welded using a 1.5 kW CW CO2 Rofin laser as a welding source. Hole-drilling method was used to compute the maximum principal stress in and around the HAZ of both sides of the joint. The experiment was designed based on a three factors five levels full central composite design (CCD). Twenty different welding runs were performed in a random order, 6 of them were centre point replicates and the maximum residual stresses were calculated for each sample. Design-expert software was used to fit the experiential data to a second order polynomial. Sequential F test and other adequacy measures were used to check the model’s performance. The results show that the developed models explain the residual stress successfully. Using the developed models, the main and interaction effect of the process input variables on the residual stresses at either side of the weld were investigated. It is found that all the investigated laser parameters are affecting the performance of the residual stress significantly.
Monitoring the Evolution of Fatigue in Corrugated Paperboard under Random Loads
Authors: Garcia-Romeu-Martinez M.A. , Rouillard Vincent , Sek Michael A. , Cloquell-Ballester V.A.
Published: March 2009

During the transportation phase of the distribution cycle, packaging systems are subjected
to random dynamic compressive loads that arise from vibrations generated by the vehicle. The level
and severity of these dynamic compressive loads are generally a function of the vibration levels, the
stack configuration and stack weight. The container’s ability to withstand these compressive loads
for sufficiently long periods depends on the material’s characteristics as well as the container
design. The research presented herein tests the hypothesis that cumulative damage in the material
under random dynamic compression will result in a reduction in the overall stiffness as well as an
increase in the overall damping of the element. These are expected to be manifested, respectively,
as a shift in the fundamental resonant frequency as well as an increase in the bandwidth of the
frequency response function of the material at resonance when configured as a single degree of
freedom system. The paper presents the results of preliminary experiments in which a number of
corrugated paperboard samples were subjected to dynamic compressive loads by means of broadband
random base excitation with a vibration table coupled with a guided dead-weight arrangement.
The level of cumulative damage in the sample was continuously evaluated by monitoring the
stiffness and overall damping of the sample which were extracted from the Frequency Response
Function (FRF) of the system. This was obtained from continuous acceleration measurements of the
vibration table and the guided dead weight.
Local Strain Measurement in Hot Deformed Microstructures
Authors: Pinna C. , Lan Yong Jun
Published: March 2009

The deformation of metals at high homologous temperatures typical of industrial forming processes such as hot rolling is investigated using an electron micro-lithography technique enabling strain measurements at the scale of the microstructure of these metals. Grids with a typical 5 μm pitch have been laid on the surface of an aluminium alloy and a stainless steel deformed by plane strain compression at 400oC and 850oC respectively. In-plane strain values can be computed from the displacements of the intersections of the grids. Strain maps can then be plotted over representative areas of the microstructures together with strain distributions within each phase of the microstructure. Results obtained for a commercial high-purity aluminium alloy with 5% magnesium show a strong localisation of deformation at triple points with a local equivalent strain value of 1.7 for a 0.22 applied strain at 400oC. As for the two-phase stainless steel deformed to a strain of 0.3, results show a high heterogeneity of deformation within each phase with a localisation of deformation into bands in the ferrite phase and local values reaching more than two times the applied compression.