bluuebunny/crossref_metadata_2025 huggingface dataset:
Fretting Fatigue: Advances in Basic Understanding and Applications
Authors: Mutoh Y , Hoeppner DW , Kinyon SE
Published: April 2008

Description

Gain an understanding of the fretting fatigue phenomenon and for developing fretting fatigue design. Fretting is well known to degrade fatigue strength significantly. Fretting fatigue failure has been increasingly disclosed in service components because those components have suffered more severe loading conditions than before due to the demands of save-energy and environment-preservation.

Twenty-nine peer-reviewed papers cover:

Fretting in Steel Ropes and Cable—reviews the topic.

Fretting Wear and Crack Nucleation—covers the process of fretting crack nucleation under fretting wear through both detailed in-situ observations and mechanical models, which included not only fracture mechanics but also interface mechanics.

Fretting Fatigue Crack and Damage—discusses fretting fatigue crack propagation under mixed mode, based on the fracture mechanics approach.

Life Prediction—addresses fretting fatigue life estimations, based on various approaches including fracture mechanics, notch fatigue analysis and multiaxial fatigue parameters.

Fretting Fatigue Parameter Effects—covers effects of parameters that influence fretting fatigue behavior and strength, including contact pressure, friction coefficient, contact pad geometry, and mating material.

Loading Condition and Environment—addresses the effect of loading conditions including block loading, high frequency and service loading.

Titanium Alloys—discusses titanium alloys, which have been typically used for structural components suffering fretting fatigue, such as turbine components and bio-joints, due to their lightweight as well as excellent corrosion resistance.

Surface Treatment—deals with improvements of fretting fatigue strength by using coating techniques.

Case Studies and Applications—introduces case studies on electrical cables, dovetail joints, pin joints and rollers.

This volume is a valuable resource for engineers that need to develop an understanding of fretting fatigue and also serves the fretting fatigue community including both newcomers and those that have been involved for some time.
Predictive Material Modeling: Combining Fundamental Physics Understanding, Computational Methods and Empirically Observed Behavior
Authors: Kirk MT , Natishan ME
Published: April 2008

Description

Get the latest information on how to extend the design life of structures and accurately predict both the fundamental material behavior and structural response under a wide range of load conditions.

Nine peer-reviewed papers cover:

Ferritic Steels—addresses fracture in the transition regime, on the upper shelf, and in the creep range. This section also examines the Gurson and Weibull models to predict fracture performance and account for constraint loss.

Electronic Materials—discusses the application of the Weibull models used extensively for steel fracture to assess the interfacial fracture of electronic components. These models predict well conditions similar to the calibration dataset.

Computational Techniques—covers advanced computational and experimental techniques to develop constitutive models for composite and shape memory materials.
Effects of Neutron Irradiation on Microstructure and Properties of Zircaloy
Authors: Adamson RB
Published: April 2008

An historical review is given on the effects of neutron irradiation on the microstructure and properties of Zircaloy. Topics included are basic neutron damage structure, precipitate instabilities, irradiation growth, deformation and mechanical properties, and corrosion. A personal perspective is given by the author, and an extensive list of references covers the area.
Understanding Hydrogen in Zirconium
Authors: Sawatzky A , Ells CE
Published: April 2008

Selected examples of the Canadian contribution to the development of understanding of the behavior of hydrogen in zirconium alloys are reviewed. To solve the technical problems faced by the nuclear industry, it was necessary to have values for the solubility and diffusivity of hydrogen in the alloys, the diffusivity needed for the three gradients of concentration, temperature, and stress. With these quantities known, sensible models for the accumulation of hydrogen at points in the reactor components and the morphology of the resultant hydride phase were developed.
Evolution of Dislocation and Precipitate Structure in Zr Alloys Under Long-Term Irradiation
Authors: Averin SA , Panchenko VL , Kozlov AV , Sinelnikov LP , Shishov VN , Nikulina AV
Published: April 2008

Tubes from zirconium-base alloys are used widely in the pressure tube reactor core. The lifetime of the zirconium component in the reactor core will be determined by structure changes and alloy properties under long-term neutron irradiation. The studies were carried out using Zr-1Sn-1Nb-0.4Fe (E635) and Zr-2.5Nb (E125) alloy samples cut out of a pressure tube (PT) in the initial condition and after 7 and 15.5 years operated (42 000 and 95 000 effective hours) under irradiation to the neutron fluxes of 3 × 1017 and 2 × 1017 n/m2 s (E > 1 MeV) at 304°C in RBMK-1000 and 314°C in RBMK-1500, respectively. The E125 alloy PTs were in two conditions, as cold worked and annealed (A) and as thermomechanically treated (TMT-1) (B). The E635 alloy PTs were cold worked and annealed (A) (Tablel). The examinations were implemented using analytical transmission electron microscopy (TEM), energy dispersive X-ray (EDX), and X-ray diffraction (XRD) analyses. New data showing the microstructure changes are presented. Both the alloys have a partially recrystallized grain structure with a high density of intragranular dislocations in the initial state. The main part of dislocations belong to ⟨a⟩ type. Density of secondary phase precipitates is high. They are β-Nb (bec) in Zr-2.5Nb. In Zr-1.3Sn-1Nb-0.4Fe, precipitates consist of Zr, Nb, and Fe, and the constituent ratio is close to 1:1:1 Zr(Nb,Fe)2 (hcp). Linear dislocations (Type a) are annealed under irradiation, while the density of ⟨c⟩-component dislocations is not practically changed. Grain structure of the Zr-2.5Nb alloy is retained, and it is practically completely recrystallized in Zr-1.3Sn-1Nb-0.4Fe. The phase structure and microchemical composition are modified by irradiation. Nb concentration changes in β-Nb are observed in Zr-2.5Nb. A substantial decrease of Fe concentration and irradiation defect accumulation are observed in the intermetallic precipitates Zr(Nb,Fe)2 in the E635 alloy. This leads to crystal lattice disordering and new precipitates Nb-enriched are formed. Dislocation loops are formed under irradiation. Loop dimensions vary widely in Zr-2.5Nb. They show a tendency to ordering under high-fluence irradiation. Uniform structure of loops with a high tendency to ordering is formed in the alloy Zr-l.3Sn-lNb-0.4Fe; 70% of them are interstitial loops of the ⟨a⟩ type. Irradiation-induced Fe depletion of intermetallic particles and a Fe content increase in saturated α-Zr matrix may be a cause of the microstructure and performance changes in E635 alloy pressure tubes. The correlation between irradiation-induced dislocation structure and hardening of the E125 alloy is discussed.
The Terminal Solid Solubility of Hydrogen in Zirconium Alloys
Authors: McMinn A , Darby EC , Schofield JS
Published: April 2008

An experimental program has been carried out to measure the terminal solid solubility (TSS) of hydrogen in Zircaloy. Unirradiated electron beam (EB) welded Zircaloy-2, EB-welded Zircaloy-4, Zircaloy-2 pressure tube, cold-worked β-quenched Zircaloy-2 forging, oxygen-strengthened tungsten inert gas (TIG) welded Zircaloy-4, and irradiated welded Zircaloy-2, welded Zircaloy-4, and Zircaloy-2 pressure tube materials were tested. A differential scanning calorimetry technique was used to measure the dissolution and precipitation temperatures for a range of hydrogen concentrations.

The TSS behavior of unirradiated EB welded Zircaloy-2 and Zircaloy-4, Zircaloy-2 pressure tube, and β-quenched Zircaloy-2 forging materials was very similar, indicating little influence of chemical composition or microstructure on TSS. There was a marked hysteresis between the dissolution (TSSd) and precipitation (TSSp) temperatures, and best fit equations are provided for the two curves.

Oxygen-strengthened TIG welded Zircaloy-4 exhibited markedly different solubility behavior to the other unirradiated materials. The oxygen addition increased the hydrogen solubility. Two explanations have been postulated for the effect, either an increase in the matrix strength or hydrogen trapping at the solute atoms. However, increasing the matrix strength in Zircaloy-2 by cold working did not increase hydrogen solubility.

Zircaloy-2 and Zircaloy-4 materials, irradiated to fluences in the range 5.5 × 1020 to 1.0 × 1022 n/cm2 (E > 1 MeV) at temperatures in the range of 250 to 300°C, have higher dissolution and precipitation solubilities compared to those measured on unirradiated material. When the irradiation damage was annealed out at 500°C, the TSS temperatures tended to be restored to the unirradiated values. It has been hypothesized that the effect of irradiation is to trap hydrogen at the irradiation damage sites, although a second explanation involving the increase in matrix strength due to irradiation has also been considered.

For unirradiated Zircaloy, thermal history was found to affect TSSp but not TSSd. Increasing the peak temperature or the hold period at peak temperature reduced the TSSp temperature. This effect is considered due to a reduction of the “memory effect” in which preferential sites for hydride precipitation are removed by the annealing. Heating and cooling rates over the range 0.5 to 10°C/min had little effect on the measured dissolution and precipitation temperatures.
Influence of Texture on the Fracture Toughness of Unirradiated Zircaloy Cladding
Authors: Grigoriev V , Pettersson K , Andersson S
Published: April 2008

The correlation between texture and fracture toughness of the cladding has been investigated in connection with axial cracks in fuel rods. The effect of texture might be expected from the influence of texture on the anisotropy of contractile deformations which, in turn, is expected to modify the stress-strain conditions at the crack tip, and, consequently, alter the crack propagation resistance of the cladding.

Stress-relieved and recrystallized Zircaloy-2 cladding with known texture parameters were tested under uniaxial tension in the axial and circumferential directions. The anisotropy of contractile deformation in uniaxial tests was characterized by means of Hill's parameters F, G, and H. The fracture toughness of the cladding was evaluated by means of the pin-loading tension test.

An influence of texture on the fracture toughness has been found for as-received cladding. A higher fracture toughness, i.e., higher resistance to an axial crack propagation, was observed for the cladding with more radial texture. No significant effect of the test temperature on the anisotropy constants F, G, and H has been observed between 293 and 573 K. The parameters F, G, and H are only slightly affected at 573 K by a hydrogen concentration of about 500 wt ppm. More data are needed to draw conclusions about the effect of texture in hydrided cladding.
Degraded Fuel Cladding Fractography and Fracture Behavior
Authors: Edsinger K , Davies JH , Adamson RB
Published: April 2008

An increase in the frequency of fuel degradation following a primary breach in boiling water reactor (BWR) rods was observed during the late-1980s and early 1990s; these rods were often found to contain axial splits. Several failed rods containing splits have been returned to the Vallecitos Nuclear Center (VNC) for post-irradiation examination (PIE). This paper describes in detail the characteristics of fracture in these rods and relates the observations to postulated mechanisms of split formation.

Crack initiation invariably occurred at localized hydrides well away from the primary defect. Crack propagation was almost entirely brittle except for fracture of the zirconium liner, which was typically ductile. Fractography of the matrix exhibited nonsymmetrical chevron features with the crack front generally leading near the outside of the cladding. Detailed metallography demonstrated that cracks propagated through regions of both high and low (i.e., 150 ppm) hydride concentrations with the same brittle features.

A modified Charpy test was developed to elucidate the effects of metallurgical and stress state variables on the crack phenomena and provide relevant fracture toughness measurements as a function of hydride level for thin-walled tube specimens. A parallel series of tests examined the role of the environment on cracking behavior. The sum of the information provides valuable insight into the mechanism of split formation in degrading fuel rods.
Failure Mechanisms of Irradiated Zr Alloys Related to PCI: Activated Slip Systems, Localized Strains, and Iodine-Induced Stress Corrosion Cracking
Authors: Fregonese M , Régnard C , Rouillon L , Magnin T , Lefebvre F , Lemaignan C
Published: April 2008

The impact of irradiation damage accumulated in fuel claddings on their mechanical behavior and their susceptibility to iodine-induced stress corrosion cracking (I-SCC) was studied in irradiated zirconium and standard Zircaloy-4 sheets subjected to interrupted tension tests in methanol/iodine solutions and in an inert environment. The study of the I-SCC cracks has been carried out by SEM, while the characterization of the irradiation defects and the activated slip systems used TEM.

In irradiated material, the deformation appears to be entirely localized early in shear bands, which form much later in non-irradiated specimens. The analysis of the activated slip systems reveals in irradiated materials a large majority of basal slip with an ⟨a⟨ Burgers vector, while in non-irradiated material prismatic slip is widely predominant. These observations are analyzed as the result of the interaction between irradiation defects and slip systems.

In the iodine environment, intergranular cracks are observed to be preferentially localized in these highly deformed regions where slip bands are emerging. Thus, the localization of the deformation in irradiated material is shown to make the SCC initiation step easier. When the test is not interrupted, in irradiated specimens the rupture occurs at about 3% total plastic strain, with a large amount of transgranular pseudo-cleavage and fluting, unlike the non-irradiated specimens tested in similar conditions.

These observations are discussed in terms of an adsorption mechanism, irradiation-induced hardening, and strain softening.
Zirconium Alloy Cold Pilgering Process Control by Modeling
Authors: Aubin JL , Montmitonnet P , Mulot S
Published: April 2008

Pilgering is a very complex tube-rolling process in which the metal undergoes a large number of deformation steps. Thus, a good knowledge of the complex strain and stress history is necessary to have better control of tube quality.

We have built a rather simple and fast 3D analytical model to be used directly for process optimization and tool design. It describes the mechanical conditions prevailing during 1he pass as a function of tool design, rolling parameters, and friction. It is based upon a geometrical definition of strains transformed into stresses via the von Mises plastic flow rule and a slab method. This model also includes shear strain computation within a radial-longitudinal tube plane using an upper bound model. Rolling forces are deduced and compared with experiments, and a damage function is computed.

We have also applied the finite element method to pilgering to get more detailed local information on the material behavior under tool contact. It provides us with the possibility of checking the hypotheses of the analytical model.

The results of these models are compared with experimental results and are used to improve quality and productivity in industrial applications.
Influence of Composition and Fabrication Process on Out-of-Pile and In-Pile Properties of M5 Alloy
Authors: Mardon J-P , Charquet D , Senevat J
Published: April 2008

Within the scope of the optimization of the M5 cladding tubes made of ternary alloy (Zr, Nb, O), an extensive program of investigation and industrial development has been undertaken. The various possible factors and potential causes of variability have been thoroughly analyzed with the aid of industrial-scale or laboratory ingots from the point of view of their impact on the finished product properties.

In this way, all the chemical composition variabilities of the alloying elements (Nb, O) and impurities (Fe, S, C) have been studied through variable-composition ingots. Also, a number of manufacturing process variants (number of melts, quench, extrusion, heat treatments, pilgering …) have been studied. In some cases, it was possible to investigate the combined effect of two types of parameters (sulfur-process and iron-process interactions). For each of the products manufactured in this way, systematic characterization of: creep, microstructure (optical microscopy, TEM), corrosion (autoclave) tests was accomplished. In each case, the influence of each variability parameter was tested, and in many cases correlations with the out-of-pile characteristics of the finished tubes were established.

Lastly, for some variables (process, S content, …) the effect of irradiation was more specifically analyzed. These investigations pointed to a new and very important factor, the effect of sulfur concentration on the in-pile operating properties, especially creep and growth.

This set of results constitutes a database covering the whole industrial variability range of this alloy, allowing Framatome to embark upon its industrial development phase and to offer M5 cladding tube on the market.

This product has been irradiated over a wide range of PWR service and environmental conditions in Europe and the U.S. The improvements in corrosion (Factors 3 to 4), hydriding (Factors 5 to 6), and creep and growth (Factors 2 to 3) data after five cycles (55 GWd/tU) show impressive gains over optimized low-tin Zircaloy-4.
Contribution to a Better Understanding of the Detrimental Role of Hydrogen on the Corrosion Rate of Zircaloy-4 Cladding Materials
Authors: Blat M , Legras L , Noel D , Amanrich H
Published: April 2008

The kinetics of waterside corrosion of Zircaloy-4 in PWR systems reveal accelerated reaction rates at high burnup levels. In such cases, a thick and dense hydride layer is observed beneath the metal/oxide interface. Laboratory corrosion tests on samples prehydrided using gaseous and cathodic charging techniques clearly indicate a deleterious effect of hydrogen on the corrosion rate. This effect increases with the hydrogen level, particularly in the case of dense hydride layers formed by cathodic charging. The purpose of the present work was to confirm the detrimental effect of hydrogen over a wider range of experimental conditions [steam, primary light water (2 ppm Li, 1000 ppm B), heavy water and air] to determine whether or not it is due to matrix damage during the charging process and to contribute to the understanding of the mechanisms involved.

With respect to the effect of the hydrogen-charging technique, a detailed examination of representative specimens after cathodic charging was performed using SEM and TEM. The main conclusions of these observations are that no evolution or degradation of the α-Zr matrix or second-phase particles could be identified after hydrogen charging. Moreover, these results are supported by steam corrosion tests on materials with the same hydrogen level and different surface properties (cathodic charging with and without homogenizing heat treatment, pickled or untreated outer surface, gaseous charging).

As a result of these investigations, the detrimental effect of hydrogen has been confirmed in different environments studied (primary light water, air, heavy water). Many different techniques were used to study the oxide and the effect of the hydrides. The periodicity of the stratification within the oxide was shorter on prehydrided specimens, and the density of cracks was higher in oxide grown above a dense hydride layer. TEM examination close to the metal/oxide interface showed no significant variation in the oxide morphology, with no change in either the defect population (shape, number, size, etc.) or the zirconia crystallites, which remain essentially columnar.

These results are discussed in relation to the different working hypotheses concerning the mechanisms involved, i.e., mechanical degradation of the oxide integrity or modification in the transport properties of the oxide grown on hydrided metal.
Stress Distribution Measured by Raman Spectroscopy in Zirconia Films Formed by Oxidation of Zr-Based Alloys
Authors: Godlewski J , Bouvier P , Lucazeau G , Fayette L
Published: April 2008

Raman spectroscopy is used to characterize zirconia films formed on Zircaloy-4 and Zr-1%Nb-0.12%O oxidized in pure water and in water containing 70 ppm of Li as LiOH at 360°C in an autoclave.

Raman spectra of monoclinic and tetragonal zirconia change across the thickness of the oxide films. The use of a high-pressure cell enabled us to calibrate the line frequency variation of monoclinic zirconia with pressure. Thus we obtained the distribution of compressive stress in the zirconia films. By developing a model, it was possible to use the Raman spectra to obtain the distribution of compressive stresses and of the fraction of the tetragonal phase in the oxide films. Using Raman imaging, we showed that tetragonal zirconia is formed in large quantities close to the metal/oxide interface.

The distribution of the compressive stresses changes according to the oxidation stage. In the case of Zircaloy-4 oxidation in water containing 70 ppm of Li as LiOH, the appearance of Phase III correlates with the gradual decrease of compressive stresses close to the metal/oxide interface. The level and distribution of the stresses in the zirconia films depend on the chemical composition of the alloy and the oxidizing medium.
Multi-Scale Characterization of the Metal-Oxide Interface of Zirconium Alloys
Authors: Bossis P , Lelièvre G , Barberis P , Iltis X , Lefebvre F
Published: April 2008

The structure of the metal-oxide interface and its effect on the stability of the corrosion layers, hydrogen uptake, and the global oxidation kinetics are studied using a systematic multi-scale characterization of the oxide layers formed on autoclaved Zircaloy-4 samples. The multi-scale approach made use of complementary tools: metallography on cross sections, SEM coupled to image-processing analysis, TEM with EDX analysis, and ionic imaging by SIMS. In addition to these local characterizations, impedance measurements were used to give global information about the oxide protective characteristics.

SEM observations show a wavy interface and the existence of lateral cracks distributed throughout the oxide layer. Image-processing analysis of 15 randomly chosen images of each sample allows a correlation to be established between the roughness of the interface and the formation of cracks. On the metal-oxide interface, a band-like region composed of grains having a ω-Zr hexagonal structure and containing large amounts of oxygen is occasionally seen by TEM and EDX, also indicating oxygen flux variations along the interface. Ionic imaging shows a correlation between the localization sites of hydrogen in the oxide and the presence of intermetallic precipitates, which is also linked with the detection of zirconium hydrides in the metal underneath. This is understood as an indication of preferred routes for hydrogen ingress through the metal-oxide interface.

This multi-scale approach highlights some differences: the oxide appears to be composed of two distinct sublayers having different properties in terms of conductivity and transport, and the oxygen and hydrogen fluxes do not seem homogeneous through the inner protective layer and across the metal-oxide interface. The link between these different results and the global oxidation kinetics is discussed.
Estimation of Lifetime Under Non-Isothermal Conditions
Authors: Blaese D , Schmachtenberg E
Published: April 2008

One possibility for prediction of lifetime of polymer products is given by the estimation of the limits of application by time-temperature-extrapolation of measured damage processes. A time-lapsing method for describing aging is given by the extrapolation with the statement of Arrhenius. If the temperature is not constant over lifetime there are two possibilities to estimate lifetime by time-lapsing lifetime tests. When the maximum temperature is supposed for the whole lifetime, an overdimensioning of the product is the result. The other way is a functional estimation of time-temperature-collectives for a more precise prediction of lifetime, which is shown in this presentation.
The Usefulness of HDT and a Better Alternative to Describe the Temperature Dependence of Modulus
Authors: Sepe MP
Published: April 2008

The vast majority of the short-term properties that appear in a material data sheet are measured at room temperature. The heat deflection temperature (HDT) represents the only systematic attempt to characterize elevated temperature performance. The HDT test describes a particular response to temperature under a very specific set of conditions, however it is often used in the material selection process as a maximum continuous use temperature. As the trend toward the computerization of property data has progressed, the tendency to rank order properties for a large number of materials from different families has increased the separation between the property value and its significance to the design engineer.

This paper will briefly review the HDT test as defined in the ASTM Test Method for Deflection Temperature of Plastics Under Flexural Load (D 648) and the International Standards counterpart, ISO 75. It will then discuss an alternative method for capturing a more complete picture of the effect that temperature has on modulus. This technique, known as dynamic mechanical analysis (DMA), provides an excellent tool for evaluating materials and comparing their mechanical performance over a wide range of temperatures.
Tension Testing of Thin Bulk Adhesive Specimens
Authors: Albrecht P , You J , Albrecht M , Eley K
Published: April 2008

This paper describes a method of measuring the tensile properties of a bulk adhesive — including modulus of elasticity, yield stress and strain, and tensile strength and strain. The authors developed the method unaware of ASTM Test Method for Tensile Properties of Thin Plastic Sheeting (D 882). Not surprisingly, requirements founded on common sense are the same in the ASTM Standard as in the present study.

Augmenting ASTM D 882, this paper offers suggestions on (1) building tensiometers for low-load tests including a load cell and displacement-controlled loading apparatus, (2) building environmental chambers housing multiple tensiometers per chamber, (3) controlling relative humidity and temperature, (4) casting adhesive sheets, (5) cutting strip specimens from the sheets and preparing them for testing, (6) conditioning the specimens, (7) applying displacements with a computer-controlled stepper motor, and (8) acquiring data automatically.

The need to carefully control the environment and strain rate is shown with stress-strain curves that were measured at different relative humidities (15, 50 and 85%), temperatures (-15, 30 and 50 °C) and initial strain rates (10-2, 10-4, 10-6 and 10-8 s-1).

Five series of tests were conducted to determine the effects of batch, loading method, environment, strain rate, and adhesive. The results show that the testing system is highly reliable. Stress-strain curves of replicate specimens tested in the same environment and at the same strain rate are highly reproducible.

The testing system is suited particularly well for thin film specimens of any material whose tensile properties are affected by relative humidity and temperature such as epoxy, acrylic, gelatin, photographic emulsion, and many kinds of paints and plastics.
Notched Impact Testing of Thermoplastics: A New Perspective
Authors: Leevers PS , Douglas M
Published: April 2008

The toughness of unreinforced thermoplastics is often high, but limited by a transition to brittle behaviour with increasing impact speed and decreasing temperature. Izod or Charpy impact strength data are widely regarded as a primary performance index for these materials, but cannot be used for quantitative design. Although fracture mechanics analysis offers a substantial advance, the impact fracture resistance for some polymers varies substantially with configuration (the shape and size of the body and the impact speed) rather than being a material constant as expected. A model of brittle impact fracture as a process of local fusion within a rapidly-loaded crack-tip craze explains this variation quantitatively. The model leads to a method of correlating impact fracture in different configurations, which is demonstrated here using a case study.
Composite Materials: Testing and Design, Fourteenth Volume
Authors: Bakis CE
Published: April 2008

Description

Twenty-two peer-reviewed papers cover a variety of topics, including testing and design methods related to high speed fiber reinforced composite rotors for energy storage in space applications. Fiber reinforced polymer composite rotors are ideal for light-weight flywheel energy storage devices because of their high strength to density ratio. Eight peer-reviewed papers on composite flywheels cover material properties testing, nondestructive evaluation, manufacturing, time dependent deformation, burst testing, and containment.

This new volume also addresses computational simulation as it relates to composite material behavior and verification testing strategies, infrastructure applications, and general topics dealing with testing and design.

Five sections cover

Research & development engineers, and university and government laboratory researchers will find this new publication to be a valuable resource.
International Comparison of Impact Verification Programs
Authors: McCowan CN , Pauwels J , Revise G , Nakano H
Published: April 2008

A horizontal comparison is made between the four laboratories that certify Charpy impact verification specimens. The participants in this study were Japan (NRLM), France (LNE), the European Commission (IRMM), and the United States (NIST). The exercise was conducted to show how the impact verification programs, specimens, and test procedures compare with each other. Results for both 8 and 2 mm strikers were compared. The study showed the following: (1) The certified energies of impact verification specimens distributed by these four metrological authorities often agreed within 1% of the average values determined in this study; (2) the variation in energy for the specimens was low, typically bracketed by a coefficient of variation of between 0.02 and 0.04; and (3) the energies measured for the tests performed with 2 and 8 mm strikers on the 4340 steel specimens were nearly equivalent, but a trend of slightly higher energy for the 2 mm tests is indicated.
European Certification of Charpy Specimens: Reasoning and Observations
Authors: Pauwels J , Gyppaz D , Varma R , Ingelbrecht C
Published: April 2008

The procedure for the production and certification of BCR (Bureau Communautaire de Reference) Charpy specimens for machine verification according to the European standard EN 10045-2 is described. A master batch is initially certified by interlaboratory comparison and is then used as a reference to certify sub-batches of similar impact toughness by comparative measurements on one dedicated machine. Extensive testing over ten years has shown that, for SAE 4340 steel, a 2 mm striker generally produces higher impact toughness than an 8 mm striker up to 120 J absorbed energy. Another observation is that asymmetric fracture generally occurs in about 50% of all cases, but that small series of tests may produce nearly all symmetric or nearly all asymmetric failures, influencing the mean value of the measured impact toughness.
Fatigue Testing and Analysis Under Variable Amplitude Loading Conditions
Authors: McKeighan PC , Ranganathan N
Published: April 2008

Description

Thirty-eight peer-review papers provide the latest information on fatigue testing and analysis under variable amplitude spectrum loading conditions focus purely on fatigue testing, fatigue design techniques, or a combination of both. This new ASTM publication serves as an important reference for engineers and scientists involved in structural integrity and component lifetime management.

Six sections cover
Indirect Verification of Pendulum Impact Testing Machines: The French Subsidiary from Its Origins to the Present, Changes in Indirect Verification Methods, Effects on Dispersion, and Perspectives
Authors: Galban G , Revise G , Mougin D , Laporte S , Lefrançois S
Published: April 2008

A straightforward method of checking pendulum impact testing machines was developed at the end of the 1970s at the request of French industrialists. This method was based on the use of reference test pieces to compare the energy provided by a reference machine with that of test (or industrial) machines. These principles are outlined in French standard NFA 03-508 and France had a national source of unnotched, reference test pieces. The manufacture of reference test pieces, characterization of calibrated batches and the indirect verification of industrial machinery therefore have been practised for twelve years or so.

Various European studies and changes in standardisation protocols have led to the replacement of unnotched test pieces by Charpy notched test pieces. France developed a source of reference test pieces of this type in the early 1990s. The French system, which is based on a partnership comprising the Fédération Française de l'Acier (French Steel Federation), steelmakers Aubert and Duval, and national laboratories (CTA and LNE), has been in operation since European standard EN 10 045-2 was first applied in 1993. Experience together with discussions between partners and users has led to considerable advances in the processes used to manufacture these test pieces, thus improving the dispersion obtained. The quality situation, especially accreditation procedures implemented by national organisations such as COFRAC (Comité Français d'Accréditation — French Accreditation Comity), has also contributed to advances in perfecting methods and assessing approximations.
Maintaining the Accuracy of Charpy Impact Machines
Authors: Vigliotti DP , Siewert TA , McCowan CN
Published: April 2008

The quality of the data developed by impact machines tends to degrade over time, due to the effects of wear and vibration that are inherent in the test. This is the reason that impact standards specify periodic direct and indirect verification tests. Each year, we provide reference specimens for indirect verification of over 800 machines around the world. From evaluation of the absorbed energies and the fractured specimens, we are able to deduce the origin of energies that are outside the allowed ranges, and report these observations back to the machine owners. This report summarizes the basis for these observations and will allow, it is hoped, machines to be maintained at higher levels of accuracy.
Evaluation of ABS Plastic Impact Verification Specimens
Authors: McCowan CN , Vigliotti DP , Siewert TA
Published: April 2008

Valid comparison of impact test energies reported by various laboratories and over time depends on consistent performance of impact test machines. To learn what information verification specimens might reveal about the impact machines used to test plastics, and to learn the critical parameters that must be controlled to minimize the scatter in the data, we tested a batch of acrylonitrile-butadiene-styrene plastic (ABS plastic) specimens. Both Charpy and Izod sample configurations were tested. We concentrated on determining the variability in impact strength, but also studied the effects of room temperature aging, exposure to sunlight, and clamping pressure (for Izod testing) on the impact strength of the ABS plastic specimens. We conclude that: (l)the variability in impact strength for the ABS plastic impact specimens is comparable to metal specimens which are now used as verification specimens to test large capacity impact machines; (2) the ABS plastic specimens did not show significant signs of aging during our tests; and (3) clamping pressures will have to be specified for verification testing of ABS plastic Izod specimens.
Skiing Trauma and Safety: Fourteenth Volume
Authors: Johnson RJ , Lamont MK , Shealy JE
Published: April 2008

Description

Authored by the world's leading experts, this new publication examines some of the leading causes of serious snow sport injuries, including prevention and treatment. Thirteen peer-reviewed papers cover:

EQUIPMENT ISSUES examine

EPIDEMIOLOGY addresses

Audience: This new publication is a valuable resource for sports medicine physicians, orthopaedic surgeons, biomechanics, sports physiologists, human biodynamics researchers, ski area management professionals, ski trade organizations, skiing equipment manufacturers, skiing coaches and trainers and any individual interested in this alpine sport.
Electron Beam Welded Charpy Test Specimen for Greater Functionality
Authors: Hughes RK , Dixon BF
Published: April 2008

Applying an electron beam weld (EBW) at the base of the notch has modified Charpy test specimens to provide a reduced scatter, sharper transition, higher upper-shelf energy and higher transition temperature for tough, high-strength steels. The procedure considerably improves determination of the ductile-brittle transition temperature (DBTT) and the reproducibility of the test.

Sectioning of the specimens after testing showed that the weld acts as a brittle crack starter at temperatures up to the transition temperature. In other words, the weld initiates cracking without absorbing significant energy itself. Therefore the test is measuring the energy necessary to drive a sharp crack through the 5.8-mm-wide unwelded ligament.

At temperatures above the transition, the fracture path switches from the weld zone to lower strength, ductile parent metal. The fracture is ductile because cracking initiates and travels through the lower strength parent metal that is ductile at these temperatures. This reflects the practical situation in which brittle weld zones may be present in steel that is inherently tough at the testing temperature.
On the Determination of Dynamic Fracture Toughness Properties by Instrumented Impact Testing
Authors: Lenkey GB
Published: April 2008

In the engineering practice it is of importance to know the effect of loading rate on the material behaviour, e.g., on the fracture mechanics properties. One of the most widely used testing techniques for determining these properties is the instrumented impact test. Depending on the material behaviour under a given loading condition, different fracture mechanics parameters should be determined. Most of the evaluation procedures of these parameters are still not standardised for higher loading rates. So the aim of the present work was to investigate the applicability of different methods for determining dynamic fracture toughness properties. Instrumented impact experiments combining with magnetic emission measurement have been performed on pre-cracked Charpy-V specimens of E420 C and QStE 690 TM high strength steels. Critical values of stress intensity factor (KId, KJi) related to the initiation of the fracture at different temperatures have been determined Using different methods depending on the type of the fracture.
Use of PCB Congener and Homologue Analysis in Ecological Risk Assessment
Authors: Valoppi L , Petreas M , Donohoe RM , Sullivan L , Callahan CA
Published: April 2008

Common analytical methods for detecting and quantifying polychlorinated biphenyls (PCBs) in environmental samples rely on matching a pattern of peaks to a series of Aroclor standards. Due to differences in degradation, partitioning, and metabolism, the PCB pattern in environmental samples can be very different from the Aroclor standards, making identification and quantification of PCBs difficult. To identify an appropriate approach for PCB analyses, the U.S. Environmental Protection Agency Region 9, Biological Technical Assistance Group (BTAG), has considered PCB environmental fate and ecotoxicity, reviewed methods and laboratory capabilities for PCB analysis, and evaluated site-specific data from California and elsewhere. Results of this review indicate analytical methods for routine measurement of specific PCB congeners are currently available, and are cost-effective in comparison with Aroclor- based methods. Accordingly, BTAG has developed a core list of congeners and a phased approach for PCB congener-specific analysis in ecological risk assessments.
Development of a Web-Based Risk Assessment Modeling System
Authors: Deliman PN , Ruiz CE , Gerald JA
Published: April 2008

The concept for a Web-Based Risk Assessment Modeling System was originally introduced during an U.S. Army Corps of Engineers Risk Assessment Modeling Workshop held in New Orleans, Louisiana, May 1998. The workshop included experts from across the country involved in the area of risk assessment modeling. The objective of the workshop was to conceptualize a procedure which could be utilized to develop a state-of-the-art modeling system to conduct risk assessments for both ecological and human endpoints. A key component for the system would be the requirement to address uncertainty involved in the modeling process. The uncertainty inherent in predicting ecological and human risk from contaminant uptake across spatial and temporal dimensions would have to be quantified. It was decided that the Army Risk Assessment Modeling System (ARAMS) would contain the following components: (1) screening level models, (2) comprehensive models, (3) population models, (4) an uncertainty component, (5) bioaccumulation databases, and (6) effects databases. ARAMS should allow the calculation of exposure concentrations in various media, the effects of the concentrations on human or ecological endpoints, and the associated risk while incorporating uncertainty. This paper describes in more detail the conceptual model constructed during the U.S. Army Corps of Engineers workshop.
Cold Starting and Pumpability Studies in Modern Engines — Results from the ASTM D02.07C Low Temperature Engine Performance Task Force Activities: Test Oil Selection and Rheological Analysis
Authors: Girshick FW , De Paz EF , May CJ , Henderson KO , Rhodes RB , Tseregounis S , Ying LH
Published: April 2008

Two series of test oils were obtained for the Low Temperature Engine Performance (LTEP) task force activities: (a) SAE 0W-30, 5W-30, 10W-30, 15W-40, 20W-50 and 25W-30 grades were fully on-specification commercial oils (LTEP 1–7), used in cold starting and Phase I pumpability studies, (b) experimental test oils for Phase II pumpability work (LTEP 20 series) either did not meet the then-current SAE J300 pumping viscosity (TP-1 MRV) limits, or showed significant D5133 gelation index values, and included nominal SAE 5W-30, 10W-30 and 15W-40 grades. LTEP participating labs provided rheological data on the oils including measurements by D 445, D 3829, D 4684, D 5133, and D 5293. Multi-temperature MRV and CCS measurements allowed correlation to the exact engine test temperatures by fitting viscosity and yield stress data to equations. The functional form of the equations is presented and explained, and the fitted coefficients are tabulated. Gelation index and gelation index temperature values, were simply averaged for each oil. For the D 3829 and D 4684 methods that measure yield stress in addition to viscosity, an adjustment was made to the measured viscosity before fitting, to allow for yield stress effects.
Cold Starting and Pumpability Studies in Modern Engines — Results from the ASTM D02.07C Low Temperature Engine Performance Task Force Activities: Phase II Pumpability Testing
Authors: Rhodes RB , De Paz EF , Girshick FW , Henderson KO , May CJ , Tseregounis S , Ying LH
Published: April 2008

The Low Temperature Engine Performance Task Force Phase II pumpability test program focused on the evaluation of six engine oils which exhibited significant yield stress or gelation index in slow-cool bench tests. The test oils were designed specifically to have abnormal flow properties and are considered to be non-commercial formulations. The light duty engines that primarily were used included the 2.2L I-4, 3.8L V-6, 4.0L I-6 and 4.6L V-8 engine, with some additional work in the 2.3L I-4, 1.9L I-4 and 3.0L V-6. Four laboratories contributed work, and each used different engines, and often, different cooling profiles, in attempts to better establish the importance of yield stress and gelation index to air-binding failures in modern engines.

For the majority of Phase II oils tested, air-binding failures were not detected. No pumping failures were detected with the phase II test oil LTEP 23, which had a gelation index of 16. Using the 4.6L V8 engine, an air-binding failure was detected only with LTEP 27, an oil that had caused air-binding failures in other work. The 2.2L I-4 engine did not fail by air-binding, but the 3.8L V-6 and 4.0L I-6 engines, which generally exhibit flow-limited failures, were “tricked” into producing air-binding failures by use of a reduced volume of test oil LTEP 28. This oil exhibited a gelation index of 40; it also exhibited a substantial yield stress (70–105 Pa) and a relatively low pumping viscosity when the engine pumping tests were run.
Cold Starting and Pumpability Studies in Modern Engines — Results from the ASTM D02.07C Low Temperature Engine Performance Task Force Activities: Summary and Conclusions
Authors: May CJ , De Paz EF , Girshick FW , Henderson KO , Rhodes RB , Tseregounis S , Ying LH
Published: April 2008

Based upon the engine and oil types evaluated in the Low Temperature Engine Performance Task Force activities, it was found that (i) modern, fuel injected, gasoline engine designs, on average, start at lower temperatures than older types, and starting temperatures are independent of number of cylinders, configuration or displacement; (ii) CCS viscosities correlated with engine startability, but at considerably higher viscosities than in J300; (iii) an operating safety margin was observed between cold starting and pumpability; and (iv) these modern designs generally exhibited flow-limited behaviour and had limiting MRV pumpability viscosities in the range of 71 to 131 Pa∙s with an average of approximately 93 Pa∙s. On the basis of limited testing of 5 multigrade oils in the Phase II pumpability testing, it was found that air-binding pumpability could be generated in certain engine types, under appropriate cooling/operating conditions. Air-binding was only observed when significant structure was detected in the oils.