bluuebunny/crossref_metadata_2025 huggingface dataset:
On The Measurement Of The Hydraulic Properties Of The Environmental Medium
Authors: Gordji SS , Pirouzian L
Published: September 2009

Contaminates behave differently in the vadose zone than they do in the saturated zone and the governing equations for them are more involved. The hydraulic conductivity and porosity are the most important parameters affecting water and contaminates movements in the vadose and the saturated zones. To estimate these parameters certain methods are examined for measuring the hydraulic properties where the soil permeability is low and, where possible, the results are compared with measured data. Unsaturated hydraulic conductivity (UHC), unlike saturated hydraulic conductivity (SHC), is difficult to obtain especially for clayey soils and fractured rocks. Most available studies either overestimate or underestimate the UHC, especially for values close to the surface where the UHC values are several orders less than their corresponding values for SHC. The goal of this paper is to adjust and modify some empirical equations for obtaining UHC and compare the results with those already available in the literature. This is achieved through the use of non-linear least squares. Values that represent parameter b, in the Campbell's power function is allowed to vary in a given range instead of having a single value. For every value in this range the non-linear least squares equations is calculated and the b value with the smallest error term is picked to represent the empirical parameter for the Campbell's power function. Results indicate adjustment to the reported empirical parameter b is needed to minimize the sums of squares and to obtain a closer match between the measured and the experimental data. That is the sum of errors for the non-linear least squares between measured and empirical data is minimum somewhere near the values that they suggested. Therefore, for the clayey soil and fractured rocks the empirical parameters for the power function are modified to reflect the minimum sums of squares for non-linear least squares equation. To fine tune b further, non-linear least squares are used to find the best fitted value of b using the empirical equation that relates depth (h) to water content. We are in the process of classifying fractured rocks and are testing them to see how their hydraulic conductivity compares with clayey, sandy and silty soils. This is done through the application of fractal geometry and use of Sierpinski carpet. The empirical and the theoretical relationships used here are simple and practical and may directly be applied to obtain corresponding UHC. The equations that are utilized here are based on the theory or have their roots in statistical modeling. Results obtained from this investigation should be compared with the field data before they are applied toward solving Richards' equation.
Determining the Hydraulic Properties of Saturated, Low-Permeability Geological Materials in the Laboratory: Advances in Theory and Practice
Authors: Zhang M , Takahashi M , Morin RH , Endo H , Esaki T
Published: September 2009

The accurate hydraulic characterization of low-permeability subsurface environments has important practical significance. In order to examine this issue from the perspective of laboratory-based approaches, we review some recent advancements in the theoretical analyses of three different laboratory techniques specifically applied to low-permeability geologic materials: constant-head, constant flow-rate and transient-pulse permeability tests. Some potential strategies for effectively decreasing the time required to confidently estimate the permeability of these materials are presented. In addition, a new and versatile laboratory system is introduced that can implement any of these three test methods while simultaneously subjecting a specimen to high confining pressures and pore pressures, thereby simulating in situ conditions at great depths. The capabilities and advantages of this innovative system are demonstrated using experimental data derived from Shirahama sandstone and Inada granite, two rock types widely encountered in Japan.
Transfer of Heavy Metals in a Soil Amended with Geotextiles
Authors: Lassabatere L , Winiarski T , Cloutier RG
Published: September 2009

Although geotextiles are increasingly employed in environmental engineering works for their hydraulic and mechanical properties, their influence on the flow and transfer of solutes, such as heavy metals, has not been fully investigated. This article considers the transfer of a tracer to characterize the flow, and three heavy metals (zinc, lead and cadmium) in a calcareous soil from a fluvio-glacial deposit with and without geotextiles, under steady state flow and saturated conditions. Leaching column xperiments were conducted. Results showed that in some cases, geotextiles can homogenize the flow and reduce heavy metals elution, while in others, the flow was heterogenized and the heavy metals were more eluted. The influence on both flow and heavy metals elution depends on the injection rate, the initial water content of the geotextile, and its properties (resistance to water penetration).
Application of the Colloidal Borescope to Determine a Complex Groundwater Flow Pattern
Authors: Narbutovskih SM , McDonald JP , Schalla R , Sweeney MD
Published: September 2009

Pacific Northwest National Laboratory staff made in situ flow measurements in groundwater monitoring wells at the U.S. Department of Energy (DOE) Hanford Site to determine the flow direction in an aquifer with a flat water table. Given the total errors in water level elevations and a gradient of a few centimeters over 500 meters, flow directions based on the potentiometric surface are ambiguous across the 200 East Area at the Hanford Site. The colloidal borescope was used because it allows direct, real time observation of mobile colloidal particles in the open interval of a water well and, thus, avoids the use of water level data. The results characterize a complex groundwater flow pattern under several buried waste storage tank farms. The aquifer, artificially high due to the large volume of liquid discharges to the soil column from Hanford's nuclear production era, is currently receding to original conditions. The aquifer lies in unconsolidated gravel beds overlying an impermeable basalt surface that has a plucked, flood-scoured, scabland structure. The current aquifer thickness is similar to the relief on the basalt surface. Thus, the groundwater must flow around the impermeable basalt structures producing a complicated flow pattern under the waste storage unit. The original monitoring network was designed for northwest flow when the water table was held artificially high. Proper locations for new wells are dependent on our knowledge of the flow direction. The results of the colloidal borescope investigation agree with the southerly direction indicated from hydrographs, contaminant trends, other direct flow data and the general concept of a receding aquifer draining off the southern limb of a basalt anticline. Flow in the aquifer is diverted by irregular local structural highs of very low permeability basalt.
Multi-Axial Composite Tube Test Method
Authors: Cohen D
Published: September 2009

This paper discusses a new multi-axial 10.2-cm (4-in.) composite tube test method. This test method is capable of loading a 10.2 cm composite tube by internal pressure, torsion, and tension/compression. The method improves on an older biaxially loaded (internal pressure and axial load) tube design used extensively by Swanson and coworkers [1–5] to characterize the failure mode of fiber dominated pressure vessels.

The 10.2 cm tube test method has been used successfully to test composite tubes by internal pressure combined with torsion and axial tension/compression. Tubes were tested at both ambient and hot/wet conditions. Tubes with various lay-ups, including, hoop and helical, and all helical configurations were tested.

This paper discusses the development of the test method. This followed by the presentation of test data for ±25/90/±25 composite tube loaded in biaxially (internal pressure combined with axial load), pure torsion, and combined biaxial with torsion load. The test data offered are limited due to space restriction. Additional data will be presented in other ASTM publications.
Structural Integrity Assessment of Composite Pressure Test Box through Full Scale Test
Authors: Parida BK , Dash PK , Hakeem SA , Chelladurai K
Published: September 2009

The design methodology of composites in aircraft structures normally follows a building block approach and validation of design allowables is carried out through coupon, feature, and full-scale component level tests. Another important aspect in the design of composites is to account for environmental degradation of strength and stiffness properties, especially under a hot-wet environment. This paper describes the methodology adopted for and the results obtained from full scale static load tests with and without pressurization, on two composite pressure test boxes, under room temperature and hot-wet environmental conditions. The test boxes representing a typical wing structure, were made of three bays with the middle bay consisting of composite spars and top and bottom skins. One of the two identical test boxes was subjected to almost saturation level moisture conditioning at 70°C and 85% RH in an environmental chamber. The test boxes were extensively strain-gaged with back to back strain gages fixed at pre-selected locations, and these were very carefully moisture-proofed to withstand the moisture-conditioning over long period and rigorous hot-wet test at 100 + 5°C and > 85% RH. A component test rig and an aluminum test chamber were specially designed to undertake these tests, which involved application of loads and reactions that cause combined bending and torsion of the test box. Finite element analysis using “ELFINI” had predicted the test box to be buckling-critical. Through actual testing it has been validated that the top skins of the test boxes do not undergo buckling up to design ultimate load (DUL) and that the ultimate failure loads were well above the DUL of the test boxes, both under room temperature and hot-wet environmental conditions.
The Development and Use of a Common Database for Composite Materials
Authors: Shyprykevich P , Tomblin JS , Vangel MG
Published: September 2009

The development of a database and guidelines for its generation are described. The developed common database guidelines include types and number of mechanical tests, test methods, and environmental conditions. Methods to reduce the test data to the level of obtaining A- and/or B-basis values include statistical procedures that allow pooling across different environments for the same failure modes in order to increase sample sizes to estimate material variability. Either Weibull or normal distribution statistics can be used. For the normal distribution, knockdown factors from mean value to A-and B-basis material (lamina) allowables were developed that are based on a large sample size for variability and a small sample size for the mean. The concept of establishing large sample (population) variability for particular failure modes has implications for the statistical significance of design allowables for notched and unnotched laminates where the test samples are historically small. In order to utilize the database, each company must demonstrate that their processing of the identical composite material results in mechanical properties that are the same as in the database. Equivalency tests, along with statistical acceptance criteria, were developed that would perform that function. In addition, the developed acceptance criteria may be used by the manufacturing company to control the quality of the incoming material. This paper will also contain an example of a database for a carbon/epoxy material along with example equivalency tests and statistics.
Mechanical Degradation of Continuous Glass Fibre-Reinforced Thermoplastics under Static and Cyclic Loading: A Prepreg Laminate — Technical Textile Comparison
Authors: Neft JF , Schulte K , Schwarzer P
Published: September 2009

The mechanical degradation of continuous glass fibre-reinforced thermoplastics (GFRT) was analysed considering differences in the semifinished products of the laminates. The investigated laminates were produced from prepregs and technical textiles (commingled thermoplastic and glass fibres stitched together with a polymeric yarn) with isotactic polypropylene (iPP) as matrix material. E-glass fibres were used as reinforcement in both systems. Static transverse and longitudinal tensile, compression and bending tests were performed. Fatigue tests were made in tension-tension (R=0.1). The matrix morphology varied due to different manufacturing procedures. The results showed a significant influence on the mechanical degradation of the semifinished products.
Computational Prediction of Yarn Structure of 3D-Braided Composites
Authors: Terpant G , Krishnaswami P , Wang Y
Published: September 2009

In order to design braiding sequences for three-dimensional braided components, a method to predict the yarn structure is necessary, because the mechanical properties of the component are dependent on the yarn structure. Satisfactory methods for predicting yarn structure based on braiding sequence are presently unavailable, although recent efforts [1] based on a finite element approach have yielded some positive results. In this paper we present a relatively efficient method based on an optimization approach. In our approach, the basic idea is to exploit the fact that the yarn structure of the braid must be the one that minimizes the total yarn length in the braid. Thus, the yarn structure can be predicted by minimizing the yarn length, subject to the condition that the yarns cannot intersect each other.
Fracture Toughness Measurements in the Transition Region Using Sub-Size Precracked Charpy and Cylindrical Bar Specimens
Authors: Lucon E , Scibetta M , Chaouadi R , van Walle E
Published: September 2009

The objective of the study presented here is the validation of direct fracture toughness measurements using two small-size geometries, which can be obtained from machining broken Charpy-V specimens: • the miniaturized precracked Charpy-V specimen (MPCCv); • the miniaturized Cracked Round Bar (MCRB). Fracture toughness results have been obtained in the ductile-to-brittle transition regime for two well-characterized reactor pressure vessel steels, and compared using the Master Curve analysis to reference data measured using bigger samples of the more conventional C(T) geometry.

To cope with specimen size limits established by test standards to avoid loss of constraint, two strategies were chosen: • testing at very low temperatures, thus approaching lower shelf conditions, • correcting fracture toughness for loss of constraint, loss of constraint was assessed by in depth finite element calculation. Sub-size results have been found in agreement with reference data, although in case of tough materials tests have to be performed at very low temperatures. From this point of view, the MCRB specimen offers the advantage that an analytical correction for the loss of constraint is already available.
Preferable Initial Crack Length for Fracture Toughness Evaluation Using sub-sized Bend Specimens
Authors: Schindler H-J
Published: September 2009

In order to guarantee maximum crack-tip constraints, fracture toughness testing standards require an initial crack length of about a0 = W/2. When performing impact tests on specimens smaller than the required size the situation is somewhat different: Since the thickness is usually not sufficient to provide plane strain conditions, it is questionable whether the initial crack length should still be about a0 = W/2 to provide maximum in plane constraints. On impact testing of small specimens, shorter cracks exhibit several experimental advantages, the main ones being, first, the lower influence of dynamic oscillations and second, the extended validity range of the measured toughness properties. For these reasons, we suggest to use shorter cracks and account for the insufficient in-plane constraints by correcting the measured (apparent) fracture toughness values. For this purpose the theoretical correction formula is derived in this paper. Based on this correction and the standard size requirements one obtains a lower-bound fracture toughness that can be used as a conservative design value. The latter is shown to be maximum for a relative crack length of about a0/W = 0.25–0.3.
The Determination of Initiation Toughness of an A533B-1 Steel using Circumferentially-Cracked Bar (CCB) Specimens
Authors: Sherry A , Wardle G , Birkett P , Wilkes M , Budden P
Published: September 2009

The circumferentially cracked bar (CCB) specimen has been developed as an alternative geometry for fracture toughness testing. A Test Procedure has been developed to formalise the use of CCB specimens for fracture toughness testing. To validate this Procedure for the assessment of ductile initiation toughness, a series of CCB tests has been carried out on a well-characterised A533B-1 steel plate. Supporting finite element analyses were performed to provide accurate η-factors for the derivation of J from load-displacement traces. Fatigue pre-cracking of specimens in rotating bend provided concentric cracks of crack depth to specimen radius ratios recommended by the Procedure. Resultant initiation toughness values, defined at 0.2 mm of ductile crack extension including blunting, were higher than the corresponding value derived using three-point bend specimens, and lower than that obtained from centre-cracked tension specimens. This ranking of initiation toughness was consistent with that expected from a consideration of crack-tip constraint. This suggests that the CCB specimen may be useful in assessing constraint effects on fracture at moderately low constraint levels.
Small Specimen Procedures for Determination of Deformation Maps
Authors: Farrell K , Byun TS , Jones JW , Gibson LT , Sitterson RG , Hashimoto N , Bailey JL , Gardner MJ
Published: September 2009

Irradiation-hardened metals undergo changes in plastic deformation modes that degrade mechanical properties. Variation of deformation mode as a function of fluence and level of strain can be tracked with deformation mode maps. Mapping requires many tensile tests and TEM specimens. To streamline the process, a special tensile test cradle and refined TEM specimen preparation techniques have been developed. The 0.25-mm-thick sheet tensile specimen with dogbone shape is sufficient to ensure bulk mechanical behavior and eliminates grinding operations for the TEM pieces. Extraneous strains that might arise in such a small specimen from pin loading or friction gripping are avoided by loading the specimen under its shoulders in a small, sliding cradle which also prevents accidental damage during remote handling in and out of the tensile machine. After straining, three TEM pieces each 1.5 mm square are cut from the gauge section in one pass in a special jig using a slow speed rotary saw fitted with ganged blades. To accommodate these square specimens during electrochemical thinning, the specimen holder is custom altered. Finally, for TEM examination, the thinned specimen is supported by an auxiliary platform constructed from molybdenum foil rings.
Subsize Specimens for Fatigue Crack Growth Rate Testing of Metallic Materials
Authors: Li M , Stubbins JF
Published: September 2009

In this work, the potential for obtaining reliable fatigue crack growth data from miniature notched bar specimens in three-point bend loading is examined. These specimens, at 2.0 mm wide by 0.8 mm thick by 7.9 mm long, are substantially smaller than any existing fatigue crack growth specimens. This work describes the development of subsize specimen fatigue crack growth rate test techniques using these miniature bar specimens. Fatigue crack growth data are reported for three alloys, 304L SS, Alloy 718 and Mod. 9Cr-1Mo steel. The data obtained using the subsize specimens compare favorably to crack growth rate data obtained on ASTM standard size specimens. The fracture surface microstructures of the subsize and standard size specimens are compared to show the similarities of the crack growth mechanisms in the two specimen configurations. Since three different materials were tested, it is possible to draw conclusions about the limitations of using these extremely small specimens in terms of material yield and ultimate strength and other standard tensile properties.
Selection of the Optimum Irradiation Fluence to Assess Annealing during Reconstitution of Charpy Impact Specimens
Authors: Otsuka E , Hatano S , Atago Y
Published: September 2009

Surveillance specimens, for example Charpy specimens, are used to monitor the effect of irradiation embrittlement on Reactor Pressure Vessel (RPV) steels. Reconstitution technology is an advanced method that can be used to avoid possible shortages of surveillance specimens in case of long-term operation beyond design life. The validation of the reconstitution technology for surveillance specimens of RPV steels down to an insert length of 10 mm requires investigating the eventual annealing effect during reconstitution. The optimum irradiation conditions for reconstitution studies of irradiated specimens were investigated based on the basic data obtained on un-irradiated specimens. The irradiation fluence of 1 × 1019 n/cm2 was found most appropriate to assess the influence of annealing during reconstitution.
Reconstitution of Charpy-V Specimens with CO2 Laser Welding
Authors: Petrov PI , Scibetta M , Puzzolante J-L , van Walle E
Published: September 2009

This paper reports on the reconstitution of reactor pressure vessel steel specimens with CO2-laser beam welding. Experiments were carried out using a 45 kW continuous wave (CW) CO2-laser with a power that varied between 9 to 32 kW. and a welding speed from 1 m/min to 5 m/min. The ability to weld pressure vessel steel by CW CO2-laser was investigated on 18MND5 steel. The laser welding parameters were optimised in accordance with the EN ISO 13919-1 standard. Qualification was performed and a procedure for reconstituting Charpy-V specimens by laser welding is established. Temperature measurements show rapid heating and cooling during the laser welding process. The maximum temperature is about 430°C at a distance of 2 mm from the weld joint and less than 300°C at a distance above 3.5 mm. Static three-point bend tests on un-notched specimens show good resistance of the weld in accordance to the RESQUE-procedure. Reconstituted Charpy-V specimens were impact tested and the results are in good agreement with non-reconstituted specimens.
Effect of Steel Making and Processing Parameters on Carbide Banding in Commercially Produced ASTM A-295 52100 Bearing Steel
Authors: Adishesha PK
Published: September 2009

Carbides are an essential phase in high carbon alloy steels used for bearing applications. Carbides provide wear resistance, inhibit grain growth and are the reservoirs of alloys, which enable the steel to develop the desired properties during heat treatment. High carbide heterogeneity and large carbides are known to affect adversely the wear resistance of bearing steels. Heterogeneity originates from the solidification process of ingots and cast blooms. An attempt has been made to study the effect of various steel making and processing parameters such as teeming/casting temperature, ingot size, reduction ratio, soaking time at the rolling temperature and heat treatment on the carbide banding in the commercially produced ASTM A 295 - 52100 type bearing steel. Carbide banding was found to decrease with the decrease in super heat and increase in the reduction ratio. Increasing soaking time at the rolling temperature also decreased the degree of banding. Increasing the austenetizing temperature or increasing the soaking time at the same austenitizing temperature also reduced the degree of banding; the effect of temperature is being more significant. High temperature soaking prior to hot rolling significantly decreased the degree of banding in continuously cast products. Carbide banding reduced with reduction in carbon content and sulphur content. Other alloying elements had very little or no significant influence on carbide banding.
Ultra Clean Steel For Anti-Friction Bearing Applications
Authors: Ganguly S , Chakrabarti I , Maheshwari MD , Mukherjee T
Published: September 2009

Bearing manufacturing technology of today enables relatively small sized bearings to have high duty ratings. Such bearings are highly stressed and more vulnerable to onset of rolling contact fatigue. Since contact fatigue is initiated at hard non-metallic inclusions, modern day bearings call for exceptional levels of cleanliness. Onset of rolling contact fatigue occurs in a statistical mode that depends on the probability of finding a hard phase of adequate size in the zone of maximum Hertzian stress. Therefore, an objective prediction of bearing life is possible only by counting the number of inclusions present per unit volume of steel with the help of ultrasound based assessment and not by the conventional chart based method.

Considerable work has been done to respond to the emerging needs of the bearing industry. The steel plant has been successfully producing both through hardening and case hardening steels satisfying the requirements of some of the leading bearing manufacturers. The present paper discusses the manufacturing process for bearing steel through Basic Oxygen Furnace-Vacuum Arc Degassing route. This paper also brings out the strategy to control oxygen and titanium. Test results obtained from some leading customers and collaborators are presented.
Machinability Control — A Topic of Great Importance to the Engineering Industry
Authors: Johansson T , Sandqvist H
Published: September 2009

More complicated and expensive machine tools together with production with limited manpower requires disturbance free and safe manufacturing, to avoid expensive and unexpected stops. The result of a machining operation is based on the interaction between manufacturing method, the machine tool and the material. There exist few well-documented test methods. Mainly the ISO 3685 is referred to, at least in Europe. This single point turning test is, however, based on cutting tools no longer available and on rather long times in cut, as the test specimen has a length of 400 – 600 mm.

In order to reach good conformity between the test results and a production environment, the applied test methods need to be fine-tuned to better simulate reality. For that reason, the ISO 3685 test method has been slightly modified and new test methods have been developed to determine a raw material's machinability. Among others ways to evaluate the impact from short machining cycles, 1 – 15 seconds, through different discontinuous machining modes have been developed, which will be described here.

Important parameters affecting the manufacturing result are tool life / tool cost versus cutting data, chip formation to avoid chip jamming, surface roughness, and component distortion. This paper will present the relationship between certain parameters and the raw material properties; steel grade and composition and cutting forces evaluated through different methods.
Influence of Hydrogen Trapped by Inclusions on Fatigue Strength of Bearing Steel
Authors: Murakami Y , Yokoyama NN
Published: September 2009

The mechanism of fatigue failure, in the extremely high cycle regime, is studied on a bearing steel, ASTM A295 52100. Special focus was given to the optically dark area (ODA) in the vicinity of fracture origin (subsurface nonmetallic inclusion) of specimens QT that received the conventional heat treatment and quenching followed by tempering. Specimens having a longer fatigue life had a larger ODA. To investigate the influence of the hydrogen trapped by inclusions on fatigue properties, specimens heat treated in a vacuum (specimens VQ) were prepared. At the identical fatigue life Nf, specimens VQ had a slightly smaller ODA than specimens QT. Hydrogen was detected around the inclusion at fracture origin of both specimens. These results were compared with those for a Cr-Mo steel, SCM435. It can be concluded that the formation of ODA is closely related to hydrogen trapped by nonmetallic inclusions. The mechanism of duplex S-N curve is also discussed.
Steel Supplier Evaluation Techniques To Assure Bearing Performance
Authors: Wolfe JO
Published: September 2009

The internal quality of steel is one of the critical factors in the performance of bearings. A multi- national company using steel from many sources around the world must have a detailed and comprehensive program for evaluating steel suppliers to assure ongoing, consistent bearing performance. There are many techniques that have been developed and used over the years such as blue fracture test, microscopic evaluation, oxygen analysis, sophisticated ultrasonic techniques and longer range tests such as fatigue life testing. The control of the process steps in making steel is a critical part of clean steel technology. Timken has developed an ultrasonic technique as well as specific sample preparation requirements to assure the quality of steel will meet the stringent requirements of bearing performance. Recent data from evaluation of many world steel suppliers will be summarized to demonstrate the importance of assuring clean steel. Ultrasonic data from several configurations of samples as well as reduction ratios will demonstrate the importance of a tightly controlled evaluation program.
Recent Evaluation Procedures of Nonmetallic Inclusions in Bearing Steels (Statistics of Extreme Value Method and Development of Higher Frequency Ultrasonic Testing Method)
Authors: Kato Y , Sato K , Hiraoka K , Nuri Y
Published: September 2009

Large microscopic inclusions from 20 to 100 μm in diameter have recently been paid attention from a viewpoint of fatigue strength of steel products. As the inclusion detection capability, or probability, is practically limited by a conventional optical microscopy, however, the evaluation of the distribution of these inclusions used to be feasible only by extraction method such as acid-solution procedure. It has been found that ultrasonic testing with 50 to 12S MHz frequency, focus-type transducers is suitable to evaluate the inclusions where the echo intensity is proportional to inclusion diameter. This paper will describe recent inclusion evaluation procedures and, as a main body, the results of the application of the new ultrasonic testing system. Included are:

The relationship between oxygen content in steel and maximum inclusion diameter in steel predicted by statistics of extreme value with the aid of microscopic image analysis, and The inclusion diameter distribution measured directly by the ultrasonic testing
A New Physically Based Model for Predicting the Fatigue Life Distribution of Rolling Bearings
Authors: Fougères R , Lormand G , Vincent A , Nelias D , Dudragne G , Girodin D , Baudry G , Daguier P
Published: September 2009

The available models are unable to estimate the fatigue life distribution of bearings explicitly taking into account material parameters. This paper presents a new model, that has been developed from a detailed analysis of damage mechanisms, for the prediction of the failure of rolling bearings operating under rolling fatigue conditions. The new approach introduces both nucleation and growth of microcracks present, or not, at the surface of the contact in the presence, or not, of inclusions. The distribution of fatigue lives is given for different loading conditions corresponding to smooth, rough or indented contacts. A good agreement is observed between the theoretical and experimental results.
Improved Bearing Steel for Applications Involving Debris, Higher Loads and Temperatures
Authors: Daguier P , Baudry G , Bellus J , Auclair G , RofèsVernis J , Dudragne G , Girodin D , Jacob G
Published: September 2009

Due to the evolution of cleanness of bearing steels, the failures observed in service conditions move from deep initiated spalling on non-metallic inclusions to surface damage due to machining marks, lack or contaminated lubrication (dents).

To take into account, by the most economic way, these request for more demanding applications, ASCOMETAL, SNR et VALTI have developed a new steel grade [1,2] based on the classical analysis of 100Cr6 (SAE 52100), with higher characteristics in terms of in-service properties (sustaining high loading, high temperature and contaminated lubrication) without deteriorated steelmaking or forming process by an optimised composition of the steel.
Wear and Corrosion Resistant PM Tool Steels for Advanced Bearing Applications
Authors: Kajinic A , Dixon RB , Hann BA
Published: September 2009

Candidate materials for the hardened steel raceways in ceramic-ball hybrid bearings, as well as steel components for other advanced bearing designs, are being increasingly specified to be capable of attaining combinations of material properties that have not previously been required of traditional bearing steels such as 52100, M50, and 440C. The desired properties may include one or more of the following: greater attainable hardness for higher static load capacity, good hot hardness and material stability at elevated operating temperatures, better adhesive and abrasive wear resistance to minimize galling or raceway damage under contaminated running conditions, good corrosion resistance for bearings which may be exposed to corrosive operating or storage environments, adequate shock loading survivability for potential satellite launching, and of course good fatigue life characteristics.

A number of recent bearing industry publications have discussed some of the properties and laboratory bearing test results for CPM® VIM CRU® 20™3, which is a cobalt-free high-carbide-volume PM high speed steel with 66 HRC minimum attainable hardness capability and good hot hardness characteristics. Although this material remains one of the leading candidates for the hardened steel raceways in several of the hybrid bearing designs developed to date, it has low chromium content and therefore inadequate corrosion resistance for the operating conditions or storage environments anticipated for other bearing applications.

This paper discusses the potential application of more recently developed high-chromium and high-vanadium PM tool steels for advanced bearing designs where the alloying has been designed to achieve a unique combination of corrosion resistance, high attainable hardness, and exceptional wear resistance.
Duplex Hardening for Aerospace Bearing Steels
Authors: Streit E , Trojahn W
Published: September 2009

A new process, duplex hardening, was developed, for two steels which are already widely used for aerospace applications, M50 and M50 NiL. The rolling contact fatigue and sliding wear performance of duplex hardened bearing components were evaluated on M50 and M50NiL steels. The rolling contact fatigue and sliding wear tests performed under the development program demonstrate superior performance of duplex hardened M50 and M50 NiL over conventional treated M50 and M50NiL bearing components. The bearing rig tests performed in this study also demonstrate superior bearing performance of duplex hardened M50 and M50NiL steels over conventional heat treated M50 resp. M50NiL steels. Under boundary lubricating conditions, the duplex hardened M50 and M50NiL bearings did not even fail after 1500 hrs. In tests with predamaged races, duplex hardened M50 bearing races demonstrated more than ten times the calculated L10-life. The tests on duplex hardened M50NiL bearings were interrupted after 1.500 hrs. runtime with no bearing failure.
Carburizable High Speed Steel Alloys
Authors: Hetzner DW
Published: September 2009

A new family of patent pending high speed steel alloys has been developed. The compositions of the steels are related to the compositions of standard high speed steels (HSS) and die steels. However, the nominal carbon content of these alloys is approximately 0.20%. These are carburizable grades of HSS. The other major compositional differences between these alloys and conventional HSS are that the new alloys contain less than 1.50% chromium. Unlike alloy M50-Nil, these new steels do not have to be pre-oxidized prior to being carburized. The modified HSS alloys are carburized using standard processing identical to the procedures used with carburizable alloy steels such as 4320, 8620 or 8720. Once carburized, the alloys are then heat treated for maximum hardness using the time and temperature cycles employed for standard HSS. That is, the steels are preheated, austenitized, quenched, and double tempered.

To offset the effect of chromium on hardenability and secondary hardening, the molybdenum, tungsten, and vanadium contents of these alloys has been increased. Complete details of calculating the specific compositions of these types of alloys will be discussed.

Lab heats of modified alloys Ml, M2 and M50 achieve surface hardnesses of 65 HRC. Residual compressive stresses in excess of −400 MPa 0.50 mm below the surface are obtained in cylindrical test specimens. Additionally, low levels of retained austenite are observed in these steels.

The ease of machining and heat treating these alloys in conjunction with their high hardness and excellent hot hardness make the steels ideal materials to be used for bearings in normal, debris, or high temperature applications.
The Development of Bearing Steels with Long Life and High Corrosion Resistance
Authors: Tanaka S , Yamamura K , Oohori M
Published: September 2009

The operating environments of rolling bearings are remarkably varied. With the use of bearings in various corrosive environments increasing, interest in stainless steel is growing. AISI 440C has been widely used in applications where corrosion resistance is of primary concern. However, its performance has not always been satisfactory because it contains coarse eutectic carbides that act as crack initiators under rolling contact stress and reduce Cr content in the martensitic matrix to the carbides. In response, we performed research to determine the most suitable bearing steel composition for both long fatigue life and noise performance and high corrosion resistance. Carbide size and hardness comparable to AISI 52100 steel were essential for the new stainless bearing steel(ES1), so we lowered the carbon and chromium contents and increased the nitrogen content of AISI440C. To control production costs, we applied conventional steelmaking processes for the nitrogen alloying. We evaluated the fatigue life and corrosion resistance of the new bearing steel(ES1). The new steel(ES1) outperformed conventional martensitic stainless steels in a tap water immersion test, a 5% aqueous sodium chloride immersion test, a saltwater spray test, noise level measuring test, water submerge life test, and oil lubrication life test.
Local Elasto-Plastic Properties of Bearing Steels determined by Nano-Indentation Measurements
Authors: Vincent A , Elghazal H , Lormand G , Hamel A , Girodin D
Published: September 2009

Methods for obtaining local elasto-plastic properties of bearing steels through nano-indentation measurements are described. The usual way to analyze the unloading part of a nano-indentation test in order to obtain the elastic modulus of nonmetallic inclusions or primary carbides in bearing steels is summarized. Then, emphasis is given to a new method mat enables one to derive the profile of micro-plastic properties of a surface hardened bearing steel. Experimentally, it consists of measuring the residual displacement dr of a spherical indenter, following loading-unloading cycles at increasing maximal force Fmax. First, the direct problem, i.e., simulating by the finite element method the nano-indentation response, dr(Fmax), from the knowledge of the strain-hardening law, σ(εp), is studied. It is validated on steel specimens that are carburised homogeneously with different carbon concentrations. Second, the inverse problem, i.e. obtaining the strain-hardening law from the nano-indentation response, is studied on carburised and nitrided layers.
Fatigue Limit Stress — A New and Superior Criterion for Life Rating of Rolling Bearing Materials
Authors: Harris TA
Published: September 2009

Rolling bearings are rated for their capabilities to withstand rolling contact fatigue. All other means of bearing failure are considered preventable through proper attention to bearing manufacture, mounting, lubrication, and minimization of contaminant ingress. The standard methods for calculation of rolling bearing capacities and fatigue lives are based on the 1947 and 1952 publications of Lundberg and Palmgren. They defined separate material factors for ball bearings and roller bearings fabricated from 52100 steel, through-hardened to at least 58 Rockwell C; the fatigue life predictions, were strongly influenced by these capacity-multiplying factors. The standard was in use for less than five years, when it became apparent bearings fabricated from ever-cleaner materials; for example vacuum degassed and vacuum melted steels, were out-performing standard life predictions. Moreover, tapered and cylindrical roller bearings routinely fabricated from carburizing steels such as SAE 4118, 4320, 8620, etc. were not directly covered by the standards. This deficiency is accommodated by the use of material-life factors applied to the Lundberg-Palmgren life equations. The Society of Tribologists and Lubrication Engineers (STLE) recommends the use of separate material-life factors to cover basic steel metallurgy, heat treatment, and metal shaping. It has been demonstrated that, together with other life factors for lubrication effectiveness and contamination, this cascading of life factors is insufficiently accurate to predict life because in most cases, these effects on bearing endurance are interdependent.

In 1985, Ioannides and Harris published a rolling bearing life prediction method based on applied and induced contact stresses and body stresses. The resultant material stresses could be combined by classical strength of materials methods of superimposition; these resultant stresses could then be compared against fatigue limit stress as the material strength criterion to determine resistance to fatigue. From 1992 through 2000, the United States Navy funded a research project to establish appropriate fatigue limit stress values for common and special rolling bearing materials and to employ such values in computerized calculation tools to effectively apply this technology to modern bearing applications. This paper presents these developments.
Evaluation of the Condensation Resistance Rating as Determined Using the NFRC 500 Procedure
Authors: Wise DJ , Shah BV
Published: September 2009

This paper presents a comprehensive and detailed assessment of the National Fenestration Rating Council (NFRC) 500 Procedure. This procedure emphasizes simulation calculations and allows the utilization of computer software in analyzing and calculating the Condensation Resistance Rating for comparative purposes. For those products that cannot be simulated, a test only option is also offered in the standard. This paper analyzes the results obtained through NFRC annual round robin tests run from 1997 to 2001. Each round robin specimen was modeled per NFRC 100 (1997): Procedures for Determining Fenestration Product U-factors and NFRC Test Procedure for Measuring the Steady-State Thermal Transmittance of Fenestration Systems using NFRC-approved computer software tools WINDOW 4.1 and THERM 2.1. The simulated results were used as a benchmark for the analysis of the testing data. All of the NFRC round robin test specimens were tested at NFRC-accredited testing laboratories.
A Thermal Stress Evaluation Procedure for Monolithic Annealed Glass
Authors: Beason WL , Lingnell AW
Published: September 2009

Thermal breakage caused by the uneven heating of glass by solar irradiance is one of the most common causes of annealed glass breakage in buildings. The classic thermal breakage situation occurs when the edges of a glass plate are shielded by the window frame system or significant building protrusions, while the central portions of the glass are not. This uneven heating situation causes tensile stress to develop along the edges of the glass. This paper presents a theoretically based procedure that can be used to estimate the level of tensile stress induced in a glass plate exposed to this typical thermal loading situation. This procedure is based on the results of a finite element parametric study and engineering judgment. In addition, an edge strength failure prediction model for annealed glass is presented which allows a designer to determine if the level of risk associated with an estimated edge stress is acceptable or unacceptable.
Design Procedure for Blast-Resistant Laminated Glass
Authors: Norville HS , Conrath EJ
Published: September 2009

When an explosive threat exists, building owners should strongly consider using blast-resistant glazing in windows and curtain walls. Architects and engineers have few, if any, publicly available tools, procedures, or formal guidelines to aid in designing blast-resistant glazing. This paper presents a design procedure for blast-resistant laminated glass. The procedure finds its basis in an empirical relationship between air blast pressure, positive phase impulse, and 60-second equivalent design loading for laminated glass and window glass constructions fabricated with laminated glass. The procedure is relatively simple to use. The paper also addresses framing considerations for the blast-resistant glazing. It gives a design example and shows comparisons with experimental results.
The Use of Glass in Buildings
Authors: Block V
Published: September 2009

Description

The broad focus of this comprehensive, new publication is the quality, design, use, and performance of architectural glass. Sixteen peer-reviewed papers cover:

Quality Issues--addresses the problems associated with the use of ASTM C1036 for field inspections of glass; the interrelationship between building codes and glass standards; on-line quality control measuring systems for tempered and heat-strengthened glass; and the impact of self-cleaning glass.

Performance Assessments--presents developments around the performance of insulating glass and glass facades, including in-situ dew point testing to assess life span of insulating glass units; and an assessment of annual energy consumption of ventilated double glass facades using computer simulation.

Glass Design--examines the structural performance of laminated glass made with stiff interlayers; design methodologies for glass, including rectangular window glass supported on three sides; large trapezoidal window glass lites; window glass design software based on ASTM E1300; and a new procedure for thermal stress evaluation of monolithic glass.

Glass in Hurricanes--addresses special design considerations for glass used in hurricane-prone areas, including retrofitting commercial structures with laminated glass and testing of annealed glass with anchored-film glass retention systems.

Glass for Fire Safety and Security--covers a broad spectrum of topics, including security glazing, fire rated glass and sprinklers, and a design procedure for blast resistant laminated glass.

Audience: This publication is a valuable resource for architects; specifiers;laboratory personnel; consultants; and glass manufacturers, fabricators, and installers.
Pesticide Formulations and Delivery Systems, 27th Volume: Traditional and Non-Traditional Developments
Authors: Martin Craig , Lindner Gregory , Rohde Arlean
Published: September 2009

Description

Thirteen peer-reviewed papers address many of the latest challenges to the agrochemical formulations industry, including lower dose products, stringent safety criteria, convenience, increased efficiency of application, and improved cost competitiveness and product differentiation.

Sections cover