ALBERT

Notes: This paper presents a short overview of the state of the art and future challenges of theuse of full-field measurements and inverse procedures to identify the constitutive mechanicalparameters of a wide range of materials. It concentrates on the so-called Virtual Fields Method(VFM) which is a tool fully dedicated to the processing of full-field measurements. Some of thefuture challenges are briefly covered here, namely the design of test configurations and theapplication to damage assessment, high strain rate testing and biomaterials. Some examples aregiven and the main scientific issues briefly discussed

Notes: This work forms part of a larger investigation into fracture detection using acousticemission (AE) during landing gear airworthiness testing. It focuses on the use of principalcomponent analysis (PCA) to differentiate between fracture signals and high levels of backgroundnoise. An artificial acoustic emission (AE) fracture source was developed and additionally fivesources were used to generate differing AE signals. Signals were recorded from all six artificialsources in a real landing gear component subject to no load. Further to this, artificial fracture signalswere recorded in the same component under airworthiness test load conditions. Principal componentanalysis (PCA) was used to automatically differentiate between AE signals from different sourcetypes. Furthermore, successful separation of artificial fracture signals from a very high level ofbackground noise was achieved. The presence of a load was observed to affect the ultrasonicpropagation of AE signals

Notes: The measurement of residual stress using the incremental hole drilling is well established, but themain limitations with the conventional strain gauge approach are the requirements for surfacepreparation, the need for accurate alignment and drilling, the restricted range of hole geometriescommensurate with the specific gauge designs, and the limited range of strain data averaged overthe footprint of the strain gauge grid. Recent attempts to extend the method have seen theapplication of full field optical techniques such as electronic speckle pattern interferometry andholographic interferometry for measuring the strain fields around the hole, but these methods aresensitive to vibration and this limits their practical use to controlled laboratory environments.There are significant potential benefits therefore of using a more robust technique based on DigitalImage Correlation (DIC), and work is presented in this study on the development of the method formeasuring surface displacements and strain fields generated during incremental hole drilling. Someof the practical issues associated with the technique development, including the optimization ofapplied patterns, the development of the optical system and integration with current hole drillingequipment are discussed, and although measurements are only presented for a single load case - theequi-biaxial stress state introduced during shot peening - the novel aspect of this work is theintegration of DIC measurements with incremental drilling and an application of the IntegralMethod analysis to measure the variation of residual stress with depth. Validation data comparingresults from conventional strain gauge data and FE models is also presented

Notes: This paper presents the modelling of the effects due to load conditions on the cervicalsection defined between C3 and C5 after a cervical plate implant is used to transfer thecompression loads from C3 to C5 as C4 is considered to be damaged as a result of a medicalcondition. For this study, three different scenarios which describe the common motion condition ofthe head-neck system are modelled. The first one refers to the effect of the head weight over theconsidered section. In the second case the average patient weight is supported by C3 and C5vertebrae. The last case simulates extreme loading conditions as vertebrae lesions occur whenthese are compressed beyond its failure limit; the ultimate stress to compression load failure valueis applied to C3. The stability and mechanical behaviour of cervical plates under compressionloading conditions is evaluated using the Finite Element Method (FEM). Cervical plates are usefulto restore stability of the spine by improving the inter-vertebral fusion, particularly when thecervical body has been damaged. The results show that the stresses on the plate and fixationscrews, for the three cases, are within the elastic range. Conversely, it has to be considered thatcortical and trabecular bone densities vary from one patient to another due to a number of factors,which can influence the fixation conditions of the screws. In the case of this analysis, healthy boneconditions were considered and the obtained results show that the risk of the integrity of the screwimplant-vertebrae system is not compromised

Notes: This article presents a first approach of hygrothermal microcracking in stitched crossplylaminates. The presentation includes the definition of the material mesostructure and the selectionof a characterization method adapted to the specificity of the study. The hygrothermal loadingselected is discussed and the evolution of the crack density in stitched crossply composites duringthe loading is presented and commented

Notes: This paper discusses the penetration behavior of fully supported sandwich panels withmicro-lattice and foam cores, and composite skins. This behaviour is of importance during foreignobject impact and perforation of sandwich structures. Experimental results are given for quasi-staticpenetration of micro-lattice and foam blocks, and it is shown that these two cellular materials arecomparable. Experimental results are also given for drop weight penetration of fully supportedskinned panels, and it is shown that skin failure and core penetration are also similar for the twocore materials. It is concluded that there is scope for improving the performance of micro-latticestructure and so making such material superior to that of aluminium foam

Notes: By atomic force microscopy, the plastic deformation marks resulting from monotonic andcyclic plastic deformation were analysed to study the plasticity in each phase of Duplex StainlessSteels. In austenite, straight slip bands were observed after monotonic loading. These straight slipbands seem to serve as fatigue extrusion nucleation sites, which are the marks of theaccommodation of the cyclic plasticity by the austenite. In ferrite, after monotonic loading, slipbands, could be classified into two different groups depending on whether they result from the bulkactivities of ferrite or whether their formation is assisted by the plastic deformation of austenite. Itwas found that the crystallographic misorientation based on a Kurdjomov-Sachs relationship is thefactor controlling one or the other type. After the first 5 loading cycles, the ferrite presents onlymonotonic plastic marks. This suggests no direct contribution of the ferrite to the accommodation ofthe cyclic plasticity

Notes: In this paper, we demonstrate that a dynamic stress concentration around Lüders band canbe directly displayed using mechanoluminescence (ML) sensing film of SrAl2O4:Eu (SAO) coated onthe surface of metal. Uniaxial tensile test of an aluminum alloy (2.5% Mg) plate coated with the SAOsensing film was performed and the ML images were recorded using a high-speed camera. CapturedML images confirmed the formation and propagation of Lüders band clearly in real time

Notes: An investigation into three dimensional fluid flow has been conducted which combinesthe use of Computational Fluid Dynamics (CFD) simulations with the experimental phenomenon ofStreaming Birefringence. A versatile flow channel was designed and built for use in conjunctionwith 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 theflow 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 laminarflow regimes and the Reynolds number of the flow was around 10. To allow direct comparisons ofthe CFD solutions with the optical results, a macro (UDF) was written to interpret the flow fieldresults from a (FLUENT6) CFD simulation. This integrated the shear stresses across the flow fieldand banded the results into fringes. A good correlation between the simulated fringes and the shearstrainrate was obtained from these observations

Notes: This paper presents data obtained from a newly-developed instrument to test the qualityof solder interconnections at high strain rate – the ‘micro-impactor’. This shear test of theinterconnection at high strain rate mimics the stress experienced by the solder joint whenundergoing shock due to drop-impact. Instrumented with a load cell and linear variabledisplacement transducer (LVDT), it also has the ability to provide dynamic impact force anddisplacement data. Earlier concepts to characterise the solder joint at high strain rates such as theminiature pendulum impact tester [1] lacked this capability. This micro-impactor was used to studythe effect of increasing silver (Ag) and copper (Cu) concentration in solder alloys on the shearstrength of the solder joint. The performance of these lead-free alloys was also compared to that ofthe well-established leaded solder. It was found that increasing the silver content increases the yieldstrength of the solder, causing the failure to occur at the brittle intermetallic layer instead of in thebulk of the solder

Notes: In this paper, we have proposed a new cohesive model to stably and accurately simulatedelamination propagations in composite laminates under transverse loads. In this model, we set up apre-softening zone in front of the original softening zone. In this pre-softening zone, the initialstiffness is gradually reduced as the interface strength decreases. However, the onset displacement forstarting the real softening process is not changed in this model. The fracture toughness of materialsfor determining the final displacement of complete decohesion is not changed too. This cohesivemodel is implemented in the explicit time integration scheme. A DCB problem is employed toanalyze the characteristics of the present cohesive model. Moreover, an experimental example oflaminates under impact loads is employed to illustrate the validity of the present method

Notes: The paper describes the manufacture of thin composite panels using high performancesheet moulding compound (SMC). Topics discussed within the paper include characterisation ofcuring and flow behaviour of SMC material, tooling design concept and determination of suitableprocessing conditions for compression moulding. A Full scale “Burst test” was carried out to evaluatethe mechanical performance of SMC panels. The overall performance of the SMC panels wassatisfactory with all panels failed beyond the specification value. The main failure mode was athrough-thickness cracking. In addition, a geometrical non-linear numerical analysis was also carriedout to investigate the stress distribution and deflection behaviour of SMC panel during “Bursttesting”

Notes: Lightweight design, using high performance composites, which directly yields a reducedneed for fuel is in the focus of new developments for traffic engineering. The increased substitutionof traditional, metal based materials by fibre-reinforced composites in the aviation industryexemplifies this trend. In addition to mechanical properties, e.g. an increase in strength, that leads todirect weight savings, or improved dynamical performance, which translates into longermaintenance intervals, i.e. longer service-life. In the field of fibre-reinforced polymer matrixcomposites possible contributions from nanotechnology are currently reviewed. The modification ofthe matrix by introducing a “nanophase” has attracted most attention up-to-date. Additionalapproaches include modification of traditional reinforcements, as well as the development of newreinforcing materials. Desired improvements include mechanical properties, interlaminar shearstrength, reinforcement in z-direction, fiber-matrix adhesion, and obtaining new functionalities.Starting from a summary of the most important effects of nano-modifiers in polymeric matrices, thepresentation will review published results on the modification of thermoset matrix fiber-reinforcedcomposites by using nanotechnology, as well as some of our own work in that field. Furthermore,applications of such modified composites in component parts are discussed

Notes: This paper presents the study of rheological and mechanical properties of MR elastomersfabricated using small and large particle. Analysis indicated that MR elastomers fabricated withbimodal particles at a specific particle ratio ingredient show enhanced MR effect compared withthose fabricated with monoparticles. MR elastomer samples were fabricated by using small andlarge particles with sizes of 5[removed info]m and 50[removed info]m respectively. Their rheological and mechanicalproperties were characterized with a MR rheometer. Experimental results agree well with theanalysis

Notes: In twin-roll strip casting process, the temperature variation of casting roll can result inroll thermal stress and fatigue. It not only affects the thermal deformation of casting roll and thegeneration of the roll surface cracks significantly, but also influences the surface quality, shape andprofile of the produced strip, and the service life of the casting roll. In this paper, a 3D couplingthermal-flow finite element modelling has been conducted. For twin-roll casting of stainless steel,the influences of the casting speed and liquid level in molten pool on the temperature field ofcasting roll have been simulated and discussed. The developed model is very helpful in optimisingthe processing parameters and the design of casting roll during twin-roll thin strip casting

Notes: This paper provides a preliminary understanding in biomechanics with respect to a fullyporous-coated (FPC) dental implant. A 2D multiscale finite element model is created for a typicaldental implantation setting. Under a certain mastication force (〈200N), a global response is firstobtained from a macro-scale model (without coated surface morphology details), and then it istransferred to a micro-scale model (with coated surface morphology details), which allowsdetermining a local biomechanical field. To facilitate the study in bone remodelling, strain energydensity and equivalent strain are analysed respectively. Different porosities of coating are taken intoaccount in this study to investigate the effect of FPC materials on these typical remodelling stimuli.The results evidently reflect the osseointegrative benefits generated from surface coating. The resultreveals that increasing in particle sizes has significant effect on biomechanical response

Notes: Drawbacks associated with permanent metallic implants lead to the search for degradablemetallic biomaterials. Magnesium alloys have been highly considered as Mg has a high biocorrosionpotential and is essential to bodies. In this study, corrosion behaviour of pure magnesium andmagnesium alloy AZ31 in both static and dynamic physiological conditions (Hank’s solution) hasbeen investigated. It is found that the materials degrade fast at beginning, then stabilize after 5 daysof immersion. High purity in the materials reduces the corrosion rate while the dynamic conditionaccelerates the degradation process. In order to slow down the degradation process to meet therequirement for their bio-applications, an anodized coating is applied and is proved as effective incontrolling the biodegradation rate

Notes: It has been recently established that mechanical indentation does not sufficientlydiscriminate between normal and degraded articular cartilage. Consequently, we have carried outpreliminary research to develop and evaluate a number of indices and parameters that cancharacterise and categorise the tissue into viable and degraded types relative to functional integrity.In this paper, we report the outcome of correlation studies between the instantaneous structuralrebound following unloading from a known level of indentation and reflected ultrasound signals,analysed in the frequency domain. We subjected 137 samples from 10 normal and 10 osteoarthriticjoints to ultrasound waves and mechanical indentation-rebound tests, and determined the degree ofcorrelation between the instantaneous rebound and the principal components of the ultrasoundspectra and further investigated this using canonical discriminate analysis that was fitted with ageneral linear model. Our results demonstrate a strong correlation between rebound and ultrasoundresults, leading to the conclusion that it is possible to determine the mechanical and structuralviability of articular cartilage using non-contact methods

Notes: This paper presents a concurrent multiscale study for the deformation mechanism of monocrystallinecopper under dynamic uniaxial tension. The multiscale simulation is based on the coupledmeshless and molecular dynamic (MD) method. Using it, the size of computational model can beextended to a large dimension (in micrometer) with an atomistic resolution. The pure MD simulationis difficult to reach this microscopic dimension because the number of atoms will be too large. In thisstudy, it has been revealed that the deformation behavior and mechanism of the copper is sensitive toits size, geometry, and loading strain rate. In addition, the Young’s modulus is found to be independentof the cross-sectional size and the strain rate range considered in this study. On the other hand, theyield stress decreases with specimen length and increases with the loading strain rate

Notes: This paper presents bonding technology of aluminum alloy by hot-dipping tin. Thedissolution curve of copper in molten tin liquid was obtained in the experiment of hot-dipping Sn.Optimal hot-dipping parameter which was suitable for soldering was designed. To elucidatecharacteristics of interfacial evolution, the microstructure of the coatings, soldered joint wereanalyzed using optical microscopy, SEM and EDX. The shear strength of soldered joints was testedas high as 39.9Mpa, which is high enough to achieve the requirement of electronic industry

Notes: Particulate reinforced Ti based metal matrix composites (MMCs) were made by in-situsynthesis using vacuum arc re-melting process. The microstructure of the Ti-6Al-4V base alloy and10 vol.% (TiB+TiC)/Ti-6Al-4V metal matrix composites was examined. The particulatereinforcements were analysed and identified TiB and TiC particles. The particle distribution wasanalysed using the quadrat method over 1620 quadrats. A homogeneous particle distribution wasfound to establish in the composites. The experimental distribution of the reinforcements agreedwell with the theoretical Poisson distribution. A skew factor, which characterizes the degree ofasymmetry of a statistical distribution, of 1.108 was determined for the particle distribution in thematerial

Notes: The conductivity and mechanical properties of carbon black (CB) filled polyethylene (PE)composites depend on the conductive filler, molecular structure of polymer matrix, and theprocessing methods which are applied. CB filled high density polyethylene without and with glassfibre (GF) composites have been manufactured using single and twin screws extruder. Thecomposite made from the single screw extruder showed a much higher conductivity than that madefrom twin screws extruder for CB/PE composites with and without glass fibre. The conductivepaths are formed at very low CB content (1wt% CB for GF/CB/PE) when using single screwextruder to manufacture. The microstructure of these composites were analysed using SEM

Notes: Eliminating common defects such as voids, bubbles and poor adhesion at interfaces willincrease the quality of laminated sandwich composite structure. We are experimenting andanalyzing the effect of mechanical vibrations applied to the curing system of composite materialsproduction, particularly on minimizing void content. The range of frequency of vibrations coveredwas from 2Hz to 8kHz, for different period of vibrations. The composite laminates were made byhand lay-up using glass fibres and vinyl-ester resin, and examined under a microscope to determinetypes and quantity of defects. The results showed reduction in the number of bubbles (as well as invoid content) at frequencies between 10Hz and 50Hz for 30 minutes of vibrations

Notes: The consumption of work rolls in cold strip mills is significant. One of the key issues forwork rolls is the surface roughness which affects the rolling stability and surface finish of the strip.The produced strip has lower surface finish if the roll surface roughness is large. However, if theroll surface roughness is small, it is not helpful for establishing the rolling process, which willreduce the productivity. In this case, a laser treatment is employed to increase the value of rollsurface roughness. In order to reduce the times of roll grinding, the cold strip mill and rollmanufacturers have developed new types of rolls such as the rolls containing Ti to increase the rollwear resistance in cold strip rolling. Results show that the new 4CrTi roll has a significantadvantage of preventing decrease of the roll surface roughness. The size and generation of particlesduring roll wear process and the effect of Ti on roll wear have been discussed

Notes: Design of gate location is a crucial factor in achieving product quality in injectionmoulding. It Influences the manner of plastic flow into the cavity. The optimum gate locationimproves quality and avoids products defects. This paper presents an investigation for the effects ofgate location on product quality in injection moulding. Plastic advisor, simulation softwareembedded in Pro/Engineer package has been used for flow analysis of plastic product for selectedgate locations. It has been shown that optimum gate location improves cooling quality resulting in abetter product quality. The previous conventional experiences by individual credited engineers havebeen considered

Notes: It was impossible to obtain the transverse friction along the strip width in mostprevious studies of cold strip rolling because the surface roughness lays were assumed to be verticalto the rolling direction. In this study, several types of oblique roughness textures were manufacturedon aluminum samples and compression tests were carried out to obtain the effect of differenttextures on the deformation behavior of surface asperity. Different surface textures resulted in verydifferent peak value of stress. It was found that stress was high and changed dramatically at theinitial compression stage but tended to be stable when the total reduction increased. The asperity ofwhich the top angle is 160° showed relatively high resistance to deformation

Notes: Illuminating fundamental aspects of plant cell wall mechanics will lead to novelbiological and engineering inspired strategies for application in the cotton and wood fiber industriesand in developing novel plant-derived materials that are increasingly seen as environmentallyfriendly alternatives. The stiffness properties of cell wall polymers such as cellulose microfibrilsand xyloglucans are known but the relationship between the composite structure of the wall and itseffective stiffness remains poorly understood. Understanding this relationship is important toengineers using and designing plant-derived materials and to biologists studying plant growth. Wehave developed a software system to generate microfibril-xyloglucan networks resembling thosefound in cell walls. Finite element analysis was implemented to predict the effective Young’smodulus of varying sizes of the microfibril-xyloglucan network. Results from the finite elementmodels show that the network’s effective moduli of the cell walls having microfibrils parallel toapplied loadings are relatively high (~90-215MPa) compared with those of the walls havingrandomly oriented microfibrils (~20-47MPa). The walls having microfibrils parallel to each otherbut perpendicular to applied loadings have lowest stiffness (~17-118kPa). The Young’s moduli aresignificantly lower than those of its constituent polymers and generally in agreement withexperimentally measured values

Notes: Porous biomaterials including porous bioceramics play important roles for hard tissuereplacement and regeneration. I this paper, porous alumina (with and without zirconia addition)ceramics were produced via coating polyurethane (PU) foams with Al2O3 (ZrO2) slurries, followedby drying at room temperature and sintering at 1300 oC. The advantage of the PU foam method wasthe achieved high pore interconnectivity, but the mechanical properties of the porous ceramics wererather poor due to the high macroporosity and the high microporosity. To remove the microporosityand strengthen the porous alumina ceramics, a lanthanum-modified aluminosilicate (LAS) glass wasused to infiltrate the alumina struts. Nevertheless, the resulting LAS-modified macroporous aluminaceramics would have no ability to bond to bone tissues. To impart a bioactivity (i.e. the ability ofbone bonding) to the bioinert porous ceramics, a bioactive glass layer was applied by dipping withthe bioactive glass slurry and sintering at 1200 oC. The twice coated porous alumina ceramicswould exhibit high compressive strengths, allow bone tissue ingrowth, and form strong bonematerialintegration. A biodegradable filler – calcium phosphate cement was also incorporated. Apossible application of the porous bioceramics would be for the maxillofacial reconstruction

Notes: The fatigue destruction is one way of expiration of pressure vessels, In order to avoid theaccident occurring, it is extremely important to carry on the fatigue analysis to the pressure vessels.First, this article introduces the definition of fatigue destruction, the primary factors of affecting thefatigue expiration, and the advantages the analysis principle when the ANSYS finite element isapplied to fatigue analysis; Then, this article carries on the stress analysis based on ANSYS softwareto the CNG storage gas pressure vessel, produces the stress distributed cloud chart, and gets the nodenumber where is the maximum stress; Finally, This article carries on the fatigue analysis based onstress analysis result, the fatigue analysis demonstrates the CNG pressure vessel is effective in theestablishment service life, Its fatigue accumulative damage coefficient is smaller than 1,Whichexplain it can satisfy the fatigue strength request

Notes: Analytical studies were made on effect of size and location of a weld defect on fatiguelife for argon-arc welded titanium alloy joint. In the analyses, a weld defect was assumed as aninitial crack, and the crack growth life was taken as total fatigue life. By using the Isida andNoguchi’s stress intensity factor solution for a plate containing an embedded elliptical subsurfacecrack under tension, the life prediction code FASTRAN3.9 was revised. A small crack methodologybased on the plasticity-induced crack-closure concept and the effective stress intensity factor range,[removed info]Keff , was used to predict the total fatigue life of welded joint, and to study the effect of the sizeand location of weld defect on fatigue life by means of the revised FASTRAN3.9 code. Limitedamounts of experimental data were used to make comparison with the predictions. The predictedfatigue lives are in reasonable agreement with experiments, and the effect of both the size andlocation of the weld defect on fatigue life was found to be significant

Notes: In-situ observation of the fatigue crack growth and 90o domain switching was carried outfor BaTiO3 ferroelectric single crystals under alternating electric field. It is shown that during theelectric cycling, the crack propagates continuously. Parallel lines of 90o domain boundaries can beseen and they flip at each reversal of the alternating electric field. The width of the 90o domainswitching zone grows with the number of cycles and its frontal always lies ahead of the crack tip. It issuggested that the cyclic stress field induced by the repeated 90o domain switching at the crack tip, aswell as the stress field caused by the electrically activated material between the electrode and thematerial under the electrodes contribute to the observed fatigue crack growth

Notes: Modern robust flutter method is an advanced technique for flutter margin estimation. Italways gives the worst-case flutter speed with respect to potential modeling errors. Most literaturesare focused on linear parameter uncertainty in mass, stiffness and damping parameters, etc. But theuncertainties of some structural nonlinear parameters, the freeplay in control surface for example,have not been taken into account. A robust flutter analysis approach in μ-framework with uncertainnonlinear operator is proposed in this study. Using describing function method the equivalentstiffness formulation is derived for a two dimensional wing model with freeplay nonlinearity in itsflap rotating stiffness. The robust flutter margin is calculated for the two dimensional wing with flapfreeplay uncertainty and the results are compared with that obtained with nominal parameter values. Itis found that by considering the perturbation of freeplay parameter more conservative flutter boundarycan be obtained, and the proposed method in μ-framework can be applied in flutter analysis with othertypes of concentrated nonlinearities

Notes: A piezoelectric active sensor network is configured to collect the wave scattering from a throughthicknesshole on an aluminium rectangular tube. It is found that guided waves are capable ofpropagating across the tube edges, while keeping the sensitivity to the damage even not on surfaceswhere the actuator and sensor are located. Signal correlation between the intact and damagedstructure is evaluated and the probability distribution of damage is thus achieved on the unfoldedtube surface

Notes: To study the fatigue microcrack initiation and propagation behaviors of castmagnesium alloys, the small fatigue crack propagation tests were carried out using the in-situobservation with scanning electron microscope (SEM). All initiations and propagations of fatiguesmall cracks focused on effects of the interaction of artificial two small holes, which there are thedifferent distances and alignments of two small holes. The results indicate that the fatigue smallcracks of cast magnesium alloys occurred mainly at the defects or root of notch but the early stagecrack propagations were influenced on the distance and alignment between two small holes. For castAM50 and AM60B alloys, the fatigue small cracking prior to occurred at the weak dendrite boundaryand had some concomitances such as the plastic deformation on surface of α-Mg phase. For AZ91alloy, the fatigue cracking characterization depended mainly on the brittle properties of β-Mg17Al12phase, which the multi cracks occurred at the boundaries of β-Mg17Al12 phase. The effect of notch onthe fatigue cracking behavior becomes weaker when the radius of notch is over 3-4 times than that ofaverage α-Mg grain size. The fatigue crack propagation behaviors varied with the differentarrangements of two small holes. The effects of distance and alignment of two small holes on thefatigue crack propagation behaviors are also obvious

Notes: In this paper, torsion fracture behavior of drawn pearlitic steel wires with different heattreatments was investigated. Samples with different heat treatment conditions were subjected totorsion and tensile tests. The shear strain along the torsion sample after fracture was measured.Fracture surface of wires was examined by Scanning Electron Microscopy. In addition, the method ofDifferential Scanning Calorimetry was used to characterize the thermodynamic process in the heattreatment. A numerical simulation via finite element method on temperature field evolution for thewire during heat treatment process was performed. The results show that both strain aging andrecovery process occur in the material within the temperature range between room temperature and435 °C. It was shown that the ductility measured by the number of twists drops at short heating timesand recovers after further heating in the lead bath of 435 °C. On the other hand, the strength of thewire increases at short heating times and decreases after further heating. The microstructureinhomogeneity due to short period of heat treatment, coupled with the gradient characteristics of sheardeformation during torsion, results in localized shear deformation of the wire. In this situation, shearcracks nucleate between lamella and the wire breaks with low number of twists

Notes: A new method for fabricating crack is introduced by pressing the wedge on bar. The pathof the crack propagation is not regular when the ratio of length and diameter is less than 1.8 on thesymmetrical support. The load of the wedge for pressing the notch is given in this paper. The 2-Dfinite element is applied to simulate the crack propagation by the maximum normal stress theory.The experimental results show that the quality of the fracture section will vary with the span on thethree-point bending. In order to control the crack propagation along the desired section regularly,the asymmetrical three-point bending is proposed. The simulation results show that when thedifference of the two spans is between 11 and 22 in asymmetrical three-point bending under theparameters condition, the good quality of the section will be obtained, and the experimental resultsalso strong support the conclusion

Notes: The use of High-pressure Vessel in eco-friendly Natural Gas Vehicles (NGV) istechnologically feasible nowadays. Common applications of High-pressure Vessel are to carryCompressed Natural Gas (CNG), hydrogen for fuel-cell vehicle, and high-compression air in thenew air-car technology. High-pressure Vessel is subjected to extreme compression-decompressioncycles that could cause fatigue failure. Therefore, vessel shall be inspected regularly to detect ifthere is crack inside. The objective of this paper is to optimize the inspection interval of CNG HighpressureVessel by means of Probabilistic Fracture Mechanics Analysis. Vessel is made of highalloysteel and assumed to have distributed elliptical cracks. Three length-to-depth crack ratios(a/c), i.e. 3, 8, and 15, are simulated. Crack is assumed to propagate in fixed ratio. Stress IntensityFactors at each crack tip are calculated by Finite Element Analysis and Crack Closure Technique.Fatigue crack growth is simulated by Cycle-by-Cycle Integration Technique. The FractureMechanics Analysis is then expanded to probabilistic analysis by considering stochastic nature ofanalysis parameters. Probability of failure is computed by Guided Direct Simulation Method usingsoftware which is specially written for this project [1]. Based on simulation result, High-pressureVessel is recommended to be inspected every 3 years

Notes: Widespread fatigue damage (WFD) is an important concern of aging aircrafts. Residualstrength of stiffened panels with widespread fatigue damage was evaluated by an engineeringapproach and a finite element method respectively. Nine stiffened panels with three types of damagewere tested for their residual strength. The predictions are in good agreement with the experimentresults and it is shown the methods could be used in an engineering practice for the residual strengthevaluation with the acceptable accuracy. It can be seen from this research that WFD could result insignificantly reduction in the residual strength of stiffened panels

Notes: Uniaxial ratchetting-fatigue interaction of tempered 42CrMo alloy steel was observed byvarious cyclic stressing tests at room temperature. The ratchetting deformation and low cycle fatigue(LCF) property of the material as well as their interaction occurred in cyclic stressing were discussed.It is shown that progressive ratchetting deformation causes the decrease of fatigue life, and the fatiguelife of the material depends greatly upon the applied mean stress, stress amplitude, maximum stressand stress ratio. Since tempered 42CrMo steel presents significant cyclic softening feature, a tertiaryratchetting is observed. Based on the experimental results, a simple and reasonable failure modelconvenient to engineering application was constructed to predict the fatigue life of the material inuniaxial cyclic stressing. The basic variables of the model are maximum stress and stress ratio, andthe effect of cyclic softening feature on the ratcheting-fatigue interaction is also included in the modelby introducing a new variable. It is shown that the predicted lives are in fairly good agreement withthe experimental ones

Notes: As the implementations of the western development in China, more and more tunnelswill get through the western mountains in China. In order to economize the construction costs, anew type of underground structural form called branching-out tunnel must be applied. The failureprocess of the branching-out tunnel under lateral overload action is also greatly complicated, whichis related with the depth of the mountains, the branching-out angle, the in-situ stress field, thethickness of the middle wall and so on. This paper uses the 3D-physical model of geo-mechanicalmodel tests to study the stability and failure process of this complicated structure, especially the partof the middle wall. The physical model is built up in a new kind of analogy material. In the processof the whole experiments, different lateral pressures imposed on both of the lateral planes of thephysical model. According to different lateral pressures, we have attained the change of the stressand displacement field and looked into the failure process of the pivotal positions in thebranching-out tunnel. We also use finite element method analysis software RFPA (Realistic FailureProcess Analysis) to simulate the whole failure process of the branching-out tunnel. Finally, wehave got the load-bearing safety reliability of this complicated structure through comparativeanalysis of physical modeling and numerical simulation

Notes: This paper shows how the number of lap of spot welded joints in automotive steel sheetschanges the life -cycle transform of itself. There has been significant developments in the lifeextension of automotive steel sheets, as well as in passenger safety. We verified the validity of theS-N curve of materials by QSTS test. Moreover, we used EZNCEN and HS40R, which are commonlyused as automotive steel sheets because of their excellence in increasing fuel efficiency. The purposeof research was to compare the fatigue life of multi - lap of spot welded joints to there. In addition s,we used the two different kinds of sheets together in the same welding under the same condition.Through this whole process, the hypothesis on the life cycle of lethargy coefficients was found to be ingood agreement with the result of the experiment. That is, when using sheets of the same materials inone welding, the fatigue life of two laps of a spot welded joint was found to be much superior byEZNCEN 5~14%, HS40R 17~30%,and when using each sheet of different materials, we found thedecrease in fatigue life by 6~16%. Finally, the best value from the data was chosen based on theexperiment for the analysis of the fatigue life of each layer

Notes: Low cyclic fatigue testing of 45 medium carbon steel with the annular V-notch indicatesthat the propagation of crack under variable amplitude increase by degrees overloading is fasterthan that under constant amplitude overloading. Some problems which include the effect ofconstant amplitude overloading to propagation speed of crack, the suitable loading process ofaccelerating propagation of fatigue crack, and the fracture figure in suitable loading, should bediscussed. Based on the experimental results and the analysis of the fracture surfaces of thespecimens, the mechanism of propagation of fatigue crack under the overloading is explored. It isproposed that at the moment of the application of the overloading, the obvious instantaneousincrease of crack growth rates is due to crack blunting. Then an adequate way of loading to makepropagation of crack quickly is found that provide a basis for the engineering application ofextra-low cycle fatigue fracture

Notes: Directionally solidified (DS) superalloys, which have elongated large grains, are used forgas-turbine blades. Since the grain size is not small enough in comparison with the crack sizeobserved often in a real component, the inhomogeneous microstructure due to the aligned grains maystrongly affect the crack propagation property. Center-cracked-plate specimens with three differentorientations, TP0 with the parallel DS axis to the load, TP90T with the perpendicular DS axis to theload and the crack propagation direction, and TP90L with the perpendicular DS axis to the load andparallel to the crack propagation direction, are subjected to high-temperature (1143K) fatigue. Thespecimens after the tests show the transgranular cracking perpendicular to the load axis in TP0,intergranular one parallel to the DS axis in TP90L, and intergranular / transgranular one parallel to theDS axis in TP90T. The crack propagation rate da/dN shows a good correlation with effective stressintensity factor range [removed info]Keff in each cases. However, the magnitude of da/dN at a same [removed info]Keff in TP90Lis relatively higher than that in TP0, and that in TP90T remarkably fluctuates. A microscopicobservation of TP90T reveals that the high da/dN is caused by the intergranular cracking, while thelow da/dN is observed on the transgranular cracking. A procedure for the prediction of crackpropagation is proposed on the basis of the two types of cracking; transgranular and intergranularcracks perpendicular to the load axis. The validity of the proposed procedure is discussed by thecomparison of tested and predicted results of crack propagation in a fatigue condition

Notes: Considering the time effect of surrounding rock and the long time stability of theunderground caverns after being excavated, a method on the finite element viscoelastic displacementbased on Kelvin model. The recursion formula is obtained by the displacement analytic solution ofKelvin model. It can be used to predict the viscoelastic displacement development fast andaccurately. Finally this method is employed into a project, and the calculated values by this methodagree well with the measured values. Prove that the method is effective

Notes: Creep properties of polymer bonded explosives (PBXs), a particulate composite, wasstudied by using the method of moiré interferometry in this paper. The specimens fabricated bydifferent heat pressing technology were used. Extensive creep deformation of PBXs material wasindirectly measured by the aid of compressive circular disk test. The obtained results shown that creepproperties are greatly influenced by pressing pressures and temperature of heat pressing technology.The results indicated that the higher the temperature and the pressing pressure are in the heat pressingtechnology to some degree, the better the PBXs material creep resistance is. The creep fracturesurfaces of PBXs were also observed using Scanning Electronic Microscopy (SEM). It was shownthat most of the fracture crack was initiated and propagated along the explosives crystal surfaceduring creep

Notes: Cracking due to the restrained shrinkage stress has been frequently observed at early age inconcrete construction. The early-age shrinkage cracking reduce the structural performance of concreteand may accelerate deterioration to shorten the service life. Two kinds of strategies andinstrumentation have been developed to assess early age cracking: ring tests with a restraining core,longitudinal tests where the restraint is at the end grips of the specimen. Early-age concrete exhibitscreep or relaxation behavior that is a typical response of viscoelastic materials. Viscoelasticconstitutive model should be used to analyze stress development of the restrained concrete. Theassessment of the risk of cracking can be based on the model with input of the estimated concretedeformation

Notes: The structural change and properties of W6Mo5Cr4V2 alloy (M2 steel) inoculated byaddition of rare earth (RE)-Ti were investigated. The results indicated that the impact toughness andfracture toughness were increased distinctly due to network eutectic carbides elimination, matrixstructure refinement, and well-distribution of eutectic carbides. The hardness of modified M2 steelhardly changed. In addition, the high temperature wear resistance was improved

Notes: This paper describes phase field simulations of the rafting behavior of γ’ phase with asimple interfacial dislocation network model. The interfacial dislocation network model accounts forthe effect of the network on the lattice misfit between γ and γ’ phases and the subsequent raftingbehavior. The model is implemented into the phase field simulation to see the dependence of therafting behavior of γ’ phases on the interfacial dislocation network. Without the dislocation networkmodel, the amount of the rafting was negligibly small. On the other hand, with the dislocationnetwork model, the γ’ phases shows a large amount of rafting, which is in good agreement with theresults of the experimental observations. Therefore, the combination of the phase field method andthe simple interfacial dislocation network model developed in this work is appropriate for thesimulation of the rafting of γ’ phases

Notes: Fine martensite could be gained in 70Mn2Mo cast steel roller after solidification by lasertreatment. The hardness and depth of hardened zone reached 920 HV (about 65HRC) and 0.6mmrespectively. After tempered in high temperature, the depth of hardened zone whose hardness wasmaintained above 430HV was 0.4mm. These results showed the better anti-tempering property andthe higher hardness and hardened depth compared with water quenching and implied the greaterapplied potentiality of laser strengthening

Notes: Phenomenological mechanism of transformation plasticity is proposed in the first part ofthe paper by use of simple model why stress in mother phase increases to reach yielding due toprogressing new phase and to induce plastic deformation even under small applied stress. Based onthe discussion, a unified constitutive model including transformation-induced and ordinal thermomechanicalplastic strain rates by introducing an effect of varying phases during phase transformationinto yield function. Thus derived constitutive equation is applied to describe strain response undervarying temperature and stress with some discussions as well as metallo-thermo-mechanicalsimulation of quenching

Notes: We demonstrate how algorithms to compute hierarchical triangular meshes. We cangenerate the hierarchical triangular meshes using level-of-detail for the mesh data structure. Weperform hierarchical regional partitions using Ward's method with hierarchical data structure toachieve the level-of-detail. The meshes using this data structure can be hierarchically compressedand be unpacked at a faster pace. Additionally, we introduce the adaptive mesh generationalgorithms for the parameters of computational mechanics by setting some kind of metrics in thelevel-of-detail

Notes: Experimental works using a drop weight impact test method have been performed on acircular sheet specimen to evaluate and to characterize the impact resistance of the sheet-type plasticcomponents designed for automotive wheel covers. Evaluation has been conducted for a set ofengineering plastics: polycarbonate (PC), acrylonitrile-butadiene-styrene (ABS) and their blend(PC/ABS). The testing results showed that the PC/ABS blend specimens failed in brittle mannerunder higher impact speeds with very few of whitening zones. Secondary cracks capturedperpendicular to fracture surface were also found in the mid-plane of the scattered PC/ABS blendspecimens. Investigation is then focused on this blend and the testing results describe that impactresistance of the specimen made of this alternative material is determined by ABS not by PC.Combination of structures between PC and ABS through the thickness in the core due to theirimmiscibility was observed by scanning electron microscope (SEM) on the etched PC/ABS specimen.This latter result well correlates the results obtained from the testing. It therefore reveals thatimmiscibility between PC and ABS in the blend plays an important role in determining the impactresistance of the components. This paper also presents simulative results of the test obtained from aFEA work by introducing a 3D- layered finite element (FE) model of the PC/ABS specimen to takeinto account effect of a layer in the core on the behavior of the blend

Notes: A unified yield criterion is proposed in this paper, which is valid for the metallicsandwich sections with various core strength and geometrical dimensions and can reduce to theclassical yield criteria for solid monolithic section and sandwich section with weak core,respectively. Then, the unified yield criterion is used to derive the analytical solution for the largedeflection of fully clamped metallic sandwich beam subject to a transversely concentrated load, inwhich the interaction of bending and stretching is considered. Comparisons of the present solutionswith experimental results are carried out and good agreements are found. It is seen that the axialstretching induced by large deflection has a significant effect on the deflection of sandwichstructure in the post-yield regime, and the load carrying capacity of metallic foam core sandwichbeam may be underestimated as the core strength is neglected in analysis

Notes: Lattice structures have ranges of thermo-mechanical properties that suggest theirimplementation in ultralight structures, as well as for impact/blast amelioration systems and heatdissipation media. Considering that proper anisotropy of structure could increase load efficiency, twokinds of 2-D lattice materials designable in specific stiffness and strength of arbitrary direction havebeen brought forward: variational thickness cell and variational direction cell. The mechanicalproperties of variational thickness Kagome cell have been analyzed, including effective elasticmodulus, yield strength and elastic buckling strength in arbitrary directions. Since the shear bucklingof 2-D lattice materials is an important collapse mode especially when relative densities are low, shearbuckling strength of various 2-D lattice materials have also been calculated. It is found that comparedwith the diamond cell, the variational thickness Kagome cell of thickness ratio, m=0.5, possesses thesame elastic modulus and yield surface, and higher buckling strength

Notes: Two-phase modelling testing was performed to study the shear strength of rock bridges ofjointed rock mass in this paper. The failure process of rock sample containing multiple collinearcracks was observed. Based on theory of fracture mechanics and analytical method, a rock-bridgefailure model was proposed and the expression of shear strength was derived. Comparison ofcalculated shear strength and the model test results was made and they agree well

Notes: A three-phase composite material specimen consisting of aggregates, mortar matrix andtheir bonding material is created through the Monte-Carlo method. The Mazars isotropic damageevolution model is used to describe the meso-mechanics damage deterioration of concrete. And thefinite element method is adopted to simulate respectively the uniaxial compression numericalmodels of two, three and full graded specimens with sphere and polyhedron aggregates. Followingare the conclusions from the test results: the ultimate load capacity of arbitrary polyhedronaggregate specimen is greater than that of the sphere one of the same grade; the size effect lawexists in these numerical models of concrete specimens; the stiffness of the polyhedron aggregates’specimen of the same grade is greater than that of the sphere ones’, and the softening curves of thesphere aggregate model are easier than those of the polyhedron by comparison in the softeningphase of stress-strain curves

Notes: Considering the influence of phase change and temperature variation on the physical andmechanical properties of low-temperature rock in cold regions, the mathematical model for theThermo-Hydro(TH) coupled problem is proposed based on the theory of convective heat transferfor porous medium. In this model, the influence of moisture migration on heat conduction in rock istaken into account, as well as the influence of temperature gradient on the seepage. The involvedparameters are determined according to the related equations given in this paper. Then the finiteelement model of a gas transmission pipeline in cold region is established using the proposedmathematical model. By selecting suitable boundary conditions, initial conditions and heatcomputation parameters, the freezing problem of low-temperature rock surrounding the pipeline isanalyzed. The calculated values of the temperature field and the measured data are basicallyconsistent, which indicates that the proposed TH coupling model for rock in cold regions isreasonable and reliable

Notes: The jointed rock mass distributed in the nature widely and its mechanical characteristicinfluenced the stability of the rock engineering badly. The cracks propagated and coalesced eachother and macroscopic failure happened. Bolts were a kind of effective reinforcement instrumentand they could prevent the cracks from propagating. However, the anchoring mechanism of boltswas not realized clearly and their reinforcement could not be reflected effectively in the numericalsimulation yet. Based on the damage mechanics, a constitutive relation and damage equation ofanchored jointed rock mass were presented in this paper. With a project application, the model wasproved to be feasible one

Notes: The spider silk is considered as a new type of biomaterials with its excellent mechanicalproperties. The mechanical properties of the spider silk are crucial to their applications. In this studythe mechanical properties of spider silk were studied with a micro-tensile system driven bymagnet-coil force actuator, which is very effective to measure the properties of low dimensionalmaterials. The Young’s modulus of the spider silk is obtained, the relationship between themechanical properties of spider silk and time is also acquired

Notes: The paper presents some preliminary experimental results dealing with electrochemicalsynthesis and corrosion behavior of various black layers types onto Al substrates, suitable to be usedas selective absorber coatings in the case of thermal energy production from solar energy, involvingseveral different procedures, respectively: (i) electrodeposition of black Ni-Mo alloy after an initialanodizing in nitric acid electrolyte that offers a very good adherence of the further applied coatings;(ii) cathodic deposition of black Mo based layers after an initial double zincating procedure; (iii)black coatings through a.c. electrochemical coloring of aluminum anodic oxides, usingAgNO3/H2SO4, NiSO4 based solutions; (iv) black composite polypyrrole films.The obtained black layers are characterized by a good throwing power, homogeneity, smoothnessand adherence, as shown by SEM and AFM investigations. Also, they present a good solarabsorption and low values of infrared emittance. To evaluate the resistance of black coating layersagainst corrosion, several accelerated corrosion tests have been performed, respectively: (i)continuous immersion in 0.5M NaCl for 408 hours with intermediary visual examinations andrecording of corrosion potential; (ii) potentiodynamic polarization curves in 0.5M NaCl; (iii)impedance spectra in 0.5M NaCl at open circuit potential using a Zahner IM6e potentiostaticequipment. The corrosion performances are discussed taking into account the applied preparationprocedures

Notes: Natural fibers are excellent substitute materials for man made fibers in making fiberreinforced composites due to their high specific strength and modulus, low density, low price, easyavailability in some countries, recyclable and degradable properties. They have raised great attentionsamong material scientists and engineers in the past decade. Many researches have been conducted tostudy the mechanical properties, especially interfacial properties of natural fiber reinforcedcomposites. However, the properties, such as mechanical performances, moisture absorptionbehaviors, et. al of natural fibers themselves have been seldom investigated. Knowing the relationshipbetween microstructures and properties of natural fibers are important for understanding the bulkproperties of natural fiber composites and also good instructions for designing bio-mimic materials.In this study, four kinds of natural fibers which were extracted from different plant sources wereinvestigated. The microstructures of these natural fibers were revealed with the aid of opticalmicroscopy. Microstructure models were thereof set up and mechanical properties for therepresentative volume element were assumed. Fiber bundle fracture models together with probabilitystatistics analysis were employed to calculate the mechanical properties of natural fibers. The resultswere compared with the experimental measurements. Different mechanical behaviors of naturalfibers which were functioned differently in the nature were clearly explained by the above studies

Notes: As a direct and simple method, essential work of fracture has been widely used forfracture measurement of ductile polymers. In this paper, fracture toughness of PC and PC/ABSalloy is experimentally investigated. A series of double edge-notched tension (DENT) specimensand essential work method are employed to measure the fracture toughness of PC and PC/ABSalloy. By the way, the critical crack tip opening displacement is obtained. Moreover, the fracturesurfaces of DENT specimens are examined by using a scanning electron microscope (SEM)

Notes: The objective of the work is to numerically study the meso-scale deformation ofamorphous glassy polymer. A molecular polymerization algorithm is employed to generatethree-dimensional (3D) random networks of polymer, in which the micro-parameters andmeso-structures, such as entanglement point, sliding point, etc. are considered. Then, 3D unit cellmodel and finite element method are used to calculate the stress and deformation relations ofpolymer. The evolution of meso-structure of glassy polymer with deformation is obtainedsimultaneously. Further, variation of the orientation of polymer chain with deformation wasquantitatively studied

Notes: The static and dynamic properties on the hoist hook of a vessel are necessary since they areaffected by the damages of a static and dynamic load. Al-Si-Mg casting alloy (AC4C-T6) is widelyused due to its good mechanical properties as well as the light weight and good casting with complexgeometries. This study accomplished a static tension test and an impact test. Based on the test resultsand fracture surface analysis, we found that there are great differences between the fracture strain andyield stress in the different extracted regions of specimen. In tensile test, yield stress were 205 MPa ata low strain rate of 5 mm/min and 220 MPa at a high strain rate of 25mm/min. In Charpy impact test,impact properties of AC4C aluminum alloy were analyzed by impacting loading versus displacementand impacting energy versus displacement. Compared the fracture strains in different strain rates,maximum fracture strain of low strain rate was mainly 10 % higher than that of high strain rate. Therewere more than 20 % differences in the strain rate. The ductile and brittle behaviors were showed inlow strain rate and high strain rate in static tensile test, respectively. The impact energy reached highwhen they were extracted from a plane region in the mold. But impact energy reached low when theywere extracted from a curved and edge region. It is demonstrated that mechanical properties andimpact energy of the samples where were extracted from a curved and edge region was lower than thatof the samples where were extracted from a plane region

Notes: At long standoff, a shaped charge with small cone angle will produce a jet with a high tipvelocity and a low tail velocity, causing it to stretch and break up, so its penetration ability intomultilayer metal targets is very weak, while the penetration depth of explosively formed projectiles istoo low to penetrate into multilayer metal targets. On account of this, the large cone angle shapedcharge, whose internal cone angle is about 100 degree, is proposed and designed in the paper. Thesensitivity of penetration effect into targets to the cone angle of the liner is investigated by experiment.The results reveal that the shaped charge penetration into multilayer metal targets with large intervalis more optimistic than that of the shaped charge with small cone angle and explosively formedprojectiles. In numerical simulation, based on interface tracking algorithm known as markers on cellline to reconstruct material interfaces, jet penetration into metal targets is simulated in atwo-dimensional multi-material Eulerian code. The numerical results are in good agreement with theexperimental ones and also indicate the interface tracking algorithm has much better resolution formoving interfaces, especially effective for large deformation

Notes: Task_D of the DECOVALEX_THMC project focus on predictive analysis of the long-termcoupled processes(up to 10,000 years) in two generic repositories, FEBEX type and Yucca MountainProject type for comparison. To better understand the coupled THM processes and their influence onthe system behavior, we have introduced a set of generic coupled THM governing equations. Basingon these equations, we develop simplified models according to given Task_D model inception phaserequest. Boiling model and empirical bentonite swelling model are introduced into generalsimulation which makes model more practical. Our numerical code FRT-THM upon this practicalmodels is developed and used in two BMT case study of Task_D. Simulation results are shown andverified in the 3rd and 4th workshop of DECOVALEX_THMC in 2005. There is a good agreementwith results of different participant teams which enhances confidence in prediction of coupled THMprocesses

Notes: Using environment simulation technology, simulation testing for environmental behaviorof concrete structure could be developed. Concrete durability experiment and its relative theoryresearch would be progressed, and it play an important role in ensuring security and durability ofstructures. Tailoring environment tests are discussed in the paper, as well as determining all kinds ofenvironmental factors of durability experiment and constructing several coupling environment.Simulation tests for environmental behavior of concrete structure will be developed based on thestudy

Notes: In this paper, scanning electron moiré method is used to measure the mechanical behaviorof Ferro-based shape memory alloys(SMA). The moiré patterns are formed by the interferencebetween a 1000 lines/mm cross-type specimen grating (which is fabricated using electron beamlithography) and the scanning lines of Scanning Electron Microscope (SEM). When the specimen issubjected to uniform tension load at the room temperature, the unloading residual strain values in thedifferent regions under the same tensile load and the values in the same region under different tensileloads are compared respectively. The shape memory effect is also studied. From the experimentalresults, it can be concluded that the proposed moiré method is highly accurate to measure themechanical behavior of microscopic field

Notes: Dynamic problems of Yoffe mode crack are studied under antiplane shear impact ininfinite orthotropic functionally graded materials. The shear modules in two directions are assumed tovary in terms with power function form of dual parameters of arbitrary time power. By using integraltransform-dual integral equations method, the stress field and dynamic stress intensity factor nearcrack tip are obtained. And the influences of material in homogenous coefficient and gradedparameters and crack moving speed to dynamic stress intensity factor are analyzed in virtue of Matlabsoftware. Results show that the dimensionless dynamic stress intensity factor will decrease with theincrease of moving speed of crack, which is opposite to the result of the dynamic problem of infinitestrip in FGM. And the dimensionless dynamic stress intensity factor will decrease with the increase ofgraded parameters and rise with the increase of material in homogenous coefficient

Notes: For the propagation of horizontally shear waves (SH-waves) in a functionally gradientpiezoelectric material (FGPM) plate, the governing equations are established by the theory ofelasticity. The Airy equations and Airy functions are applied to find the solutions of the equations.Numerical results indicate that: compared with those of SH-waves in a transversely isotropicpiezoelectric plate, remarkable difference can be observed for the dispersion properties of SH-wavesin a FGPM plate. Material coefficients gradient variation patterns do not affect higher modesdispersion properties of SH-waves in a FGPM plate for electrically open case. While for electricallyshorted case, dispersion properties of SH-waves higher modes are affected by the materialcoefficients gradient variation patterns, remarkable influences can be observed for S0 mode.Influences of materials coefficients gradient variation patterns on cutoff-frequencies of SH-waves arealso revealed. The results obtained are meaningful for the investigation and characterization ofSH-waves in inhomogeneous media

Notes: In this paper, Saint-Venant end effects for plane deformations of transversely isotropicpiezoelectric materials are investigated. The stress decay rates in linear piezoelectric strips that aretraction free with two kinds of electrical boundary conditions are considered. The characteristicequations for decay rate are obtained for symmetric and antisymmetric deformations. Numericalvalues are given for the roots with the smallest positive real part, which are associated with theslowest decay. Saint-Venant end effects of piezoelectric materials of crystal class 6mm penetratemuch further into strip than those of elastic isotropic materials

Notes: Analatom, Inc. is developing the Structural Health Monitoring (SHM) system using itsLinear Polarization Resistance (LPR) corrosion sensors combined with a Texas InstrumentsMSP430 microprocessor for lower weight, lower power, higher sensitivity, and lower cost thanconventional sensor systems. The system provides both strain and corrosion measurements in apackage a few mils thick. This combination of data provides critical assessment of structuralhealth, leading to prediction of failure. The MEMS sensors are permanently installed in a highvaluedstructure, such as a building, bridge or aircraft, and are connected to a data acquisition node.Data transmission and downloading uses a MaxStream ZigBee/IEEE 802.15.4 compliant chip for awireless, self-organizing network that has low power requirements. The sensor network provides alow-cost, non-intrusive way to detect failures, or to signal ahead of time that preventativemaintenance needs to be undertaken to prevent future more expensive replacement.Analatom, Inc. has developed the basic technology for a Portable Maintenance Support Tool(PMST). The device is unique and novel in that it uses a Micro Controller Unit in a handhelddevice to perform data analysis whilst maintaining a link with a Personal Computer based databasefor further support. The handheld prototype with a Liquid Crystal Display (LED) touch screenGUI takes readings from a variety of sensors and transfers the data wirelessly to a central PC hub.The handheld unit using the downloaded data from the sensor network can then provide a graphicdisplay and additionally transfer those data to a workstation for further data analysis. Analatom,Inc. builds on its corrosion system platform (sensors, data acquisition unit, data storage) to developa multiplexed system to obtain data from a variety of sensors, while further developing real timeintelligent algorithms to monitor corrosion rates

Notes: U. S. Army Corps of Engineers Engineer Research and Development Center,Construction Engineering Research Laboratory (ERDC-CERL), and Carlyle Consulting’s JohnCarlyle conducted a leak detection survey at a U.S. Army Installation. The age of pipes in thedistribution system ranged from 20 to 60 years. The thrust of the work was to acoustically surveyall of the underground pipelines constituting the installation’s potable water distribution system andfind any leaks. The results of the survey were that 6 leaks were discovered in the main lines, 63leaks associated with fire hydrants, freeze proof hose bibs, water meters, etc., and 33 leaks insidebuildings. Over two thousand acoustic measurements were made in order to obtain these results

Notes: Study on computational modeling of 4-stroke single cylinder direct injection dieselengine is presented. The engine with known specification is being modeled using one dimensionCFD GT-Power software. The operational parameters of the engine such as power, torque, specificfuel consumption and mean effective pressure which are dependent to engine speed are beingdiscussed. The results from the simulation study are compared with the theoretical results to get thetrue trend of the results

Notes: In this paper, the numerical stability of the SPH method under both tension andcompression conditions are discussed by using one dimensional impact models. The artificialviscosity and the conservation smoothed approach are tried to suppress both tension and compressioninstability. The result clearly shows that the occurrence possibility of tension instability is much largerthan the compression case. The comparison of the controlling techniques of the artificial viscous andconservation smoothed approach shows that the artificial coefficients are independent on thenumerical instability but can reduce some perturbation, while the conservation smoothed approachdoes well for both tension and compression cases. Considering the tension instability directly , asimple method of inserting particles to avoid the numerical instability is introduced

Notes: This paper is focused on the development of an effective numerical method to simulatebird-impact aircraft windshield events. A new Smooth Particle Hydrodynamics (SPH) which hasbeen incorporated as a solver option into the explicit finite element program PAM-CRASH wasused to model the bird. The deformation between the numerical results and the experimental resultsis in good agreement. Simulation results of a bird-impact process indicated that the SPH bird modelis more suitable to model the break-up of the bird into particles. Failure of the windshield in theexperiment was simulated, and the good agreement between the numerical and experiment indicatesthat the failure model established in the present paper is reasonable. Finally, the energy changes ofthe bird and the windshield were calculated

Notes: In this study, the rate-dependent subloading-friction model, which can rationally describethe reciprocal transition of static-kinetic frictions by the unified formulation, is proposed. Then, theone-dimensional model of spring-mass system is implemented by incorporating the present frictionmodel, and is applied to simulations of stick-slip motion. Further, we verified the validity of thepresent approach for the stick-slip motion by numerical experiments under various dynamic conditions

Notes: Anodic alumina has exhibits a homogeneous morphology of parallel pores that can beeasily controlled between 10 and 400 nm. AAO(Anodic Aluminum Oxide) structure is thetransversely isotropic material due to the parallel pores. In this study, mechanical properties of theAAO structures are measured using the nano-indentation method. Nano-indentation technique is oneof the most effective methods to measure mechanical properties of nano-structures. Investigation ofmechanical properties, such as the indentation modulus and hardness of the AAO structure withvarying nano-pore sizes, was performed using the nano-indentation method. The results showed thatthe indentation modulus and hardness decreases monotically as the pore size increases

Notes: As the size of ferroelectric nanostructures decreases, the fundamental questions of the sizedependence of the ferroelectric properties, and of their possible disappearance at a finite critical size,become crucial. In this paper, Landau-Ginzburg-Devonshire(LGD) theory is introduced to study thesize-dependent ferroelectric properties of BaTiO3 nanowires. Our results demonstrate that the Curietemperature and mean polarization decrease with the reducing of nanowire diameters. We furthershow that these size effects are significant only when the nanowire diameters are less than 20nm,Above this, the ferroelectric behaviors of nanowires are almost the same as those of bulk materialsand size effect can be neglected

Notes: We have been developing an advanced general-purpose computational mechanics system,named ADVENTURE, which is designed to be able to analyze a three dimensional finite elementmodel of arbitrary shape over 100 million Degrees Of Freedom (DOF) mesh. The one of main processmodules for solid analysis, named ADVENTURE_Solid, is based the hierarchical domaindecomposition parallel algorithm and employs the balancing domain decomposition as a solutiontechnique for linearized equations. The ADVENTURE_Solid has been successfully implemented ona single PC, PC clusters and MPPs with high parallel performances. Since the software has become aquite large system, it is not easy to install or operate the system on parallel machines by users. In thispaper, to operate such a system from a client PC through the network, the Web-based CAE system isdeveloped

Notes: Structural feasibility study on a Slidable One-Touch Extension (SOTE) fitting for profilewalleddrainage and sewer pipes was performed. SOTE fitting was developed for the purpose ofaccommodating large thermal deformation that could occur during installation, which if not treatedproperly in design can cause problems such as loosening of the pipe and in some cases cracking of thesupport constraint. SOTE fitting assembly process was examined via virtual assembly to determinethe structural soundness and thermal deformation behavior was investigated for its design efficiencyand performance. For both analyses the finite-element method was utilized and correspondingexperiments were also performed to support the findings. Finally, cyclic fatigue tests were carried outon fittings followed by the leak proof test to determine integrity of the SOTE fittings. Throughanalysis and experiments SOTE fitting was shown to perform its designed functions with requiredstructural stability

Notes: The analytical evaluation and finite element methods are used to analyze the criticalstability of the shallow spherical roof of oil storage tank with an axial symmetrical corrosion region.At first, the nonlinear finite element method is adopted to calculate the global critical load of thestorage tank roof, and the local corrosion region is equivalent to a circular corrosion pit with uniformdepth. The results show that the tank wall and inner pressure of the stored oil have slight effects on thestability of the roof. To build the formula of local critical load of the tank roof, the circular corrosionpit is separated from the whole roof and treated as a shallow spherical shell which is elasticallysupported on the rest part of the roof. The equivalent support stiffness is obtained by the deformationcompatibility at the edge of the corrosion pit. The resulted nonlinear stability equation is solved witha modified iteration method to determine the local critical load. The local critical load for anin-service corroded oil tank roof is analyzed by the proposed approach and the results are comparedwith those calculated by the conventional nonlinear finite element method with good agreement andthe geometrical parameter of the corrosion region corresponding to the minimal critical load is 9.5

Notes: An e-learning system for computer-aided engineering is developed. The system isdesigned as a Web-based rich client (or rich Internet application, RIA), so that anybody can learnCAE skills from anywhere, anytime. Mesh generation, finite element analysis and visualizationcapabilities for a set of benchmark problems, such as cantilever beam and plate with hole, areimplemented using FLASH ActionScript language. It is combined with a CAE educational program,dedicated for under-graduate students and novice engineers in mechanical and architecturalindustries

Notes: According to the requirements of the power department, a new type of inspection robot thatworks along ground wires is developed in this paper. The robot can navigate counterweights, clampsand particular the towers autonomously. The locomotion principle of tower-navigation is presented.In order to decrease the mass eccentricity of the robot, a centroid balance method is proposed. Virtualprototyping technical is used to validate the centroid balance method. It proved that the propermovement of the electric box can adjust the robot centroid distribution efficiently. Driven torque andthe power cost of the whole system both decrease a lot. And the robot works more safely

Notes: There are several studies for developing web-based CAE applications to substitute existingCAE applications. CASOW is the web-based CAE system developed by the author. The approach forimplementation of the system is to use fundamental technologies, for instance, HTML, HTTP, CSSand so on, because we cannot know whether new technologies will be alive or not. Certaintechnologies bring specific advantages to the applications, but a life time of the application would beshort. Recently a great advantage of web interface is developed. Such a representative application isGoogle Maps which doesn’t require any special software components; however the applicationrealizes interactiveness of the application. The technology is called Ajax which drastically overcomesthe bad interactiveness on the web browser. On the other hand, high efficiency of analysis work withhigh performance computers produces many kinds of knowledge and a large amount of information.We are confronted with inefficient knowledge and information management in the network system.This paper presents the new web-based CAE system using Ajax and knowledge sharing frameworkwith compatibility to web interface. The system is presented, and advantages of the interface,effectiveness of the API in the system and knowledge sharing framework are discussed

Notes: Scale, corrosion and the and biological growth in industrial water handling processesresult in reduced water flow though pipes, reduced heat transfer, and pump failures. Preventativetreatments for these problems are based upon chemical compounds that are most often toxic andenvironmentally persistent. Manufacturers continue to introduce new chemicals and treatmentprograms onto the market, and old products have been discontinued. Many manufacturers claim thatthe new chemical and treatments are more environmentally friendly and safer for the plant workersand the users. The U.S. Army Engineer Research and Development Center ConstructionEngineering Research Laboratory has undertaken a research effort to look at these new chemicaltreatments. The objective of this work was to develop “green” water treatment chemicals thatcontrol biological growth, corrosion and scale while reducing or eliminating the generation of toxicsubstances during the manufacture, use, and disposal processes

Notes: The current research has assessed the correlation between welding parameters and corrosionbehaviour for friction stir welded 6056 aluminium alloy. Different thermal treatments and weldingparameters were considered. For the welding parameters studied in this project, the data stronglyindicate that sensitivity to corrosion is linked to the welding parameters employed. Substantialdifferences were found for the higher and lower speed welding parameters, with the lower speedparameters appearantly resulting in less corrosion resistance. The most widespread form ofcorrosion observed was pitting; however, intergranular corrosion (IGC) was also seen. While theT78 thermal treatment appears to decrease the corrosion resistance of the parent alloy, the weldregion tends to improve, with the nugget being cathodic

Notes: Recently, the intravascular therapy using microcoils and stents to treat aneurysms hasattracted researcher’s interest. In this study, in order to evaluate the effects of the stents, a numericalsimulation of two-dimensional flows has been carried out for a pipe with a model of an aneurismalsac. Using aneurismal models with different inclined angles to the pipe, inflow conditions withsteady states or pulsations have been applied in the range of Reynolds number in human bloodflows. First, the computational results are compared with experiments under the steady inflowcondition, which has shown the reliability of the numerical simulation. Furthermore, the mechanismof flows with an aneurismal model is discussed in the case with or without a stent, and consequentlythe effect of the stent is clarified

Notes: The purpose of this study is to accumulate data to predict the ruptures of aneurysms on thebifurcation of the middle cerebral arteries at the base of the brain. Particular stress is laid onunderstanding the elemental nature of branch flows with/without an aneurysm. Therefore, “flowpatterns” and “wall shear stress”, which are important factors for the causes of ruptures, areinvestigated by the three-dimensional experiments in vitro and the two-dimensional numericalsimulations with simplified models. In the branch arteries without an aneurysm, there is a possibilityof growing aneurysms at the location slightly away from a stagnation point. If an aneurysm forms intoa centrosymmetric shape for the inlet axis, it is considered that they tend to grow further in asymmetrical plane. From the viewpoint of the risk of ruptures, recirculation flows becomeproblematic with the lower Reynolds number, while the influence of wall shear stress becomes largerwith the higher Reynolds number

Notes: The fracture is an important failure behavior of cancellous bone. Three-point-bendingexperiment was used to study fracture behavior of cancellous bone. Three group specimens weretaken from two human femoral head and there was a non-angled crack and an angled crack in everygroup respectively. By using Digital Speckle Correlation Method (DSCM), the displacement andstrain field were obtained at the crack-tip and the full specimen. The initial crack path was always atthe maximal strain location and could be predicted by the DSCM. In the macro-scope, the crackpropagation paths towards the load tip, and are independent of the initial crack angle

Notes: In this study, to conduct numerical simulation of desert physiognomy forming process infixed, semi-fixed and free sand desert field by considering the sand flow process by wind, thenumerical model based on the hydrodynamics and sand grains kinemics are proposed. For analyze theactual characteristic of sand movement phenomenon, the stream flow field and desert flow field areintroduced and mathematical model for numerical analysis are established by considering the sandshape, size and mass in order to describe the fixed, semi-fixed and fully free sand desertphysiographical process. Then according to the real fixed, semi-fixed and free sand flow field bycoupling with stream flow field, several models are made and numerical simulations are conducted

Notes: In this study, to conduct numerical simulation of sand dune forming processes, themathematical model for sand dune dynamics are studied. Due to sand dune dynamics and the streamfield, which includes wind flow over a dune field, analyses process is complex the uniform sand fieldand stream fields are consider for the numerical simulation process. Then the dune forming processsimulated by considering the dunes induced factor and interactions phenomenon

Notes: When a bluff body is located in a uniform flow, the flow is separated and vortices areformed. Consequently, the vortices cause “flow-induced vibrations”. Especially, if the Strouhalnumber and the frequency of the body oscillation coincide with the natural frequency, the lock-inregime will occur and we could find the large damages on it. Therefore, it is profitable, in engineeringproblems, to clarify this phenomenon and to suppress the vibration, in which the effect of elastic wallson the suppression is focused. Then, the aims of this article are to clarify the oscillatory characteristicsof the elastic body and the flowfield around the body by numerical simulations, in which a squarepillar with elastic walls is set in a uniform flow. Two dimensional incompressible flows are solved bythe continuity equation, Navier-Stokes equation and the Poisson equation which are derived by takingdivergence of Navier-Stokes equation. Results show that a small deformation of elastic walls has alarge influence on the body motion. In particular, the effect is very distinct at the back

Notes: The purpose of this paper is to investigate fluid characteristics and flat panel displaybehaviours on contact-free flat panel display handler nozzles. Since air force distributions streamingbottom surface of a flat panel display highly dependent on operating as well as design conditions andconfiguration of contact-free handler nozzle, influences of various parameters such as flow rate,supply air pressure, floating height are examined through a series of computational fluid dynamicsanalyses. Moreover, dynamic finite element analyses of the flat panel display are carried out to assurethat an oscillation effect caused by disturbances is not significant. Key findings from the bothcomputational fluid dynamics and structural integrity analysis results are presented and discussed,which can be figured out an optimized operating condition of contact-free handler nozzles

Notes: An investigation on the stability of heated panels in supersonic airflow is performed. Thenonlinear aeroelastic model for a two-dimensional panel is established using Galerkin method and thethermal effect on the panel stiffness is also considered. The quasi-steady piston theory is employed tocalculate the aerodynamic load on the panel. The static and dynamic stabilities for flat panels arestudied using Lyapunov indirect method and the stability boundary curve is obtained. The staticdeformation of a post-buckled panel is then calculated and the local stability of the post-bucklingequilibrium is analyzed. The limit cycle oscillation of the post-buckled panel is simulated in timedomain. The results show that a two-mode model is suitable for panel static stability analysis andstatic deformation calculation; but more than four modes are required for dynamic stability analysis.The effects of temperature elevation and dimensionless parameters related to panel length/thicknessratio, material density and Mach number on the stability of heated panel are studied. It is found thatpanel flutter may occur at relatively low aerodynamic pressure when several stable equilibria exist forthe aeroelastic system of heated panel

Notes: Novel low melting glasses in the MoO3-La2O3-Nd2O3 system were obtained at differentcooling rates (102 K/s and 104-105 K/s). Characterization of the amorphous samples was made bydifferential thermal analysis (DTA) and X-ray absorption fine structure (XAFS) method. Accordingto DTA data of the glass samples, the glass transition temperatures are at 325-330 0C, thecrystallization started above 410 0C and the melting temperatures are at 660-720 0C. A structuralmodel of glasses was suggested on the basis of XAFS and IR investigations. It was shown that thepredominant structural units in the amorphous network of glasses containing 90 -80 mol% MoO3are MoO6 groups. The appearance of MoO4 groups deteriorates the glass formation ability

Notes: Fluorine containing calcium aluminosilicate glasses are widely used for a number oftechnological applications including dental cements, mould fluxes in steel making and in a varietyof glass-ceramic systems. Despite of their importance these systems remain quite poorly understoodwith respect to their composition. To address this question a glass composition corresponding to theequimolar binary system anorthite−fluorite (Ca2Al2Si2O8−CaF2) was chosen as a base point for twoseries of compositions. One of the series is designed on the anorthite stoichiometry and consideredas classically charge balanced. Another series starts from the fluorine free composition of theanorthite−lime (Ca2Al2Si2O8−CaO) stoichiometry and, therefore, is characterized by a disruptednetwork with at least one non-bridging oxygen (NBO) attached to silicon. A multinuclear 19F, 27Al,29Si solid state NMR study of the glasses was undertaken. It is shown that in both series fluorine ispredominantly coordinated by calcium, F−Ca(n), and in addition interacts with aluminium formingAl−F−Ca(n) complexes, where n denotes the number of first neighbouring calcium cations. Smallamounts of high coordinated aluminium grows with increasing fluoride content in both glass series.However, the high coordinated aluminium may not be solely due to the formation of theAl−F−Ca(n) complexes. Glasses of the first series displayed systematic upfield shift of 29Si NMRresonance while substituting fluoride for oxide, starting from the fluorine free composition. Thisupfield shift is interpreted as the lack of cations in the network, due to formation of the F−Ca(n),which drives silicon network to polymerize toward a higher Qn structure. Contrary to the first series,the 29Si NMR resonance remains constant for fluorine containing compositions of the second seriesbut differs downfield from the initial anorthite glass. The latter is explained by the excess of cationsin the network due to addition of the fluorite resulting in formation of NBO on the silicon. Bindingof fluorine with silicon is considered negligible in these systems. Thus, fluorine and calcium bothdefine the degree of network polymerization and are considered as a cause for the changes in siliconand aluminium networks

Notes: The specific features of the dynamics of oxygen ions in Ме2O · SiO2 (Ме = Li, Na, K,Cs) and Na2O·ZnO·P2O5 melts at а temperature of 2000 K were investigated bу the moleculardynamics method. It is demonstrated that, as in the systems studied earlier, the formation of defectcomplexes is а necessary condition fог an oxygen diffusion event to bе successful. The scenarios ofgenerating defect соmplexes аrе described, and the lifetimes of these complexes are calculated. Thestructure of the defect complexes is determined. It is shown that two-membered rings, free andthreefold-coordinated oxygen ions сап also bе involved in the formation of defect complexes

Notes: Low melting glasses in the MoO3-Nd2O3-Bi2O3 system were obtained at slow (102 K/s)and high cooling rates (104-105 K/s). The amorphous state of the samples was proved by X-raydiffraction. Comparative analysis of the infrared spectra of the obtained glasses and other availablemolybdate spectral data was carried out. The structure of glasses with a high MoO3 content wasfound to consist of corner shared MoO6 units. The increasing of Nd2O3 and Bi2O3 lead to partialtransformation of MoO6 to MoO4 units, due to breaking of Mo-O-Mo linkage

Notes: This work aims to explore possible applications of the ab initio molecular dynamics(MD) in modeling of the soda-lime-silica (NCS) glass and melt doped with admixtures. Preparationof the basic glass (15.8 wt.% Na2O, 10.5 wt.% CaO, and 73.7 wt.% SiO2) by the MD simulationfrom scratch is described. The structure analysis of the NCS glass is presented in the form of totaland partial radial distribution functions (RDF), coordination numbers, and fractions of Qn units. Thereasonable first neighbor distances were obtained, even if a rather small basis set of electronic wavefunctionsand softer pseudopotentials for atomic core regions were applied. All major discrepanciesin the first neighbor distances can be easily explained, and the results can be improved if needed.The Qn distribution shows higher disproportionation of Q3 than NMR and Raman experimentaldata, however, it is lower than previous classical MD simulations