bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact and Fatigue Resistance of a [±30°/0°] 3-D Braided Carbon Epoxy Composite
Authors: Portanova MA , Deaton JW
Published: March 2009

The fatigue resistance of a multiaxial braided (3-D) graphite/epoxy composite in both unnotched and post-impacted conditions has been evaluated. The material tested is a [±30°/0°] multiaxial braid constructed from AS4/12K tow graphite fibers and British Petroleum E905L epoxy resin. These materials were braided as dry preforms, and the epoxy was added using a resin transfer molding process (RTM). The unnotched and post-impact specimens were tested in compression-compression fatigue at 10 Hz with a stress ratio of R = 10. The unnotched tension-tension fatigue specimens were tested at 5 Hz with a stress ratio of R = 0.1. Damage initiation and growth were documented through the application of radiography and ultrasonic through transmission (C-scans). Visible inspection of surface and edge damage was also noted to describe the initiation and progression of damage in these materials. The mechanisms leading to damage initiation were established, and failure modes were determined. Stiffness and strength degradation were measured as a function of applied cycles. These 3-D braided composite results were compared to strain levels currently used to design primary structure in commercial aircraft composite components made from autoclave-cured prepreg tape.
DDW Testing of Thermal Spray Coatings
Authors: Bowers DF
Published: March 2009

A cyclic wear-corrosion test has been established for evaluation of thermal spray coatings. While this test equipment is now used in the paper industry for assessments of thermal spray coatings on Yankee dryers, it may also be modified for other sliding wear corrosion applications. Yankee dryers have been thermally sprayed for 20 years with a marginal success rate; now for the first time, it is possible to predict their performance by DDW tests. The method drips (D), dries (D) and wipes (W) a specific chemical(s) on the surface of the heated, thermally-sprayed, specimen and the DDW cycles repeat every few seconds, monotonously. Both surface profilometer and microscopic methods are used to evaluate the material-environment interactions. DDW test results are described for the determination of environmental effects on thermal spray coatings.
Cyclic Corrosion Tests in Japanese Industries
Authors: Suga S , Suga S
Published: March 2009

It has been generally agreed that the conventional salt spray test does not correlate nor simulate actual corrosion in service. Needs for a better test method instead of the salt spray test have risen also in Japan, and the various types of cyclic corrosion tests have been designed particularly in automotive and related companies. These tests are widely utilized because of better reproducibi1ity and acceleration.

To unify these test methods the Society of Automotive Engineers in Japan organized a technical committee. After 5 years of study JASO M 609 Standard for metallic and paint coatings on steel was published in 1991. Another standard for automotive parts was made in 1992. Both are basically the same cyclic corrosion test (CCT) which comprises 2 hours of salt spray, followed by 4 hours of dry and 2 hours of wet condition per cycle.

They have been also applied to other industrial fields. Some modified CCT combined with artificial light exposure have also been developed.
Variations of a Global Constraint Factor in Cracked Bodies Under Tension and Bending Loads
Authors: Newman JC , Crews JH , Bigelow CA , Dawicke DS
Published: March 2009

Elastic-plastic finite-element analyses were used to calculate stresses and displacements around a crack in finite-thickness plates for an elastic-perfectly plastic material. Middle- and edge-crack specimens were analyzed under tension and bending loads. Specimens were 1.25 to 20 mm thick with various widths and crack lengths. A global constraint factor αg, an averaged-normal-stress-to-flow-stress ratio over the plastic region, was defined to simulate three-dimensional (3D) effects in two-dimensional (2D) models. For crack lengths and uncracked ligament lengths greater than four times the thickness, the global constraint factor was found to be nearly a unique function of a normalized stress-intensity factor (related to plastic-zone-size-to-thickness ratio) from small-to large-scale yielding conditions for various specimen types and thickness. For crack-length-to-thickness ratios less than four, the global constraint factor was specimen type, crack length and thickness dependent. Using a 2D strip-yield model and the global constraint factors, plastic-zone sizes and crack-tip displacements agreed reasonably well with the 3D analyses. For a thin sheet aluminum alloy, the critical crack-tip-opening angle during stable tearing was found to be independent of specimen type and crack length for crack-length-to-thickness ratios greater than 4.
A Numerical Study on the Influence of Geometry Variations on Stable Crack Growth in CT Specimens for Different Materials
Authors: Shan G , Kolednik O , Fischer DF
Published: March 2009

The influences of the specimen thickness, the ligament length and the overall size on the JR-curves are numerically investigated for CT specimens. The thickness effect is taken into account with 2D analyses by dividing a plain sided specimen into a plane stress part and a plane strain part. For a given geometry the overall out-of-plane constraint of the specimen is determined by the relative thickness of the plane stress and the plane strain part which can be estimated with the help of a simple tridimensional analysis. It is found that the variation of the out-of-plane constraint with the geometries of the specimens is one of the main reasons for the complicated geometry effects on JR-curves. Different patterns of geometry effects are observed for one material in our numerical analyses. Similar patterns have been reported in experimental studies found in the literature. It is also shown that different classes of material may lead to different patterns of geometry effects.
Experimental Investigation of Fracture Toughness Scaling Models
Authors: Link RE , James AJ
Published: March 2009

An experimental investigation of fracture toughness in the ductile-brittle transition range was conducted. A large number of ASTM A533, Grade B steel, bend and tension specimens with varying crack lengths were tested throughout the t-ransition region. Cleavage fracture toughness scaling models were utilized to correct the data for the loss of constraint in short crack specimens and tension geometries. The toughness scaling models were effective in reducing the scatter in the data, but tended to overcorrect the results for the short crack bend specimens. A proposed ASTM Test Practice for Fracture Toughness in the Transition Range, which employs a master curve concept, was applied to the results. The proposed master curve over predicted the fracture toughness in the mid-transition and a modified master curve was developed that more accurately modeled the transition behavior of the material. Finally, the modified master curve and the fracture toughness scaling models were combined to predict the as-measured fracture toughness of the short crack bend and the tension specimens. It was shown that when the scaling models over correct the data for loss of constraint, they can also lead to non-conservative estimates of the increase in toughness for low constraint geometries.
The Effect of Constraint Due to Out-of-Plane Stress Field on Fracture of Reactor Pressure Vessel Steel--An Experimental and Numerical Study
Authors: Rudland DL , Mohan R , Ghadiali ND , Detty D , Rosenfield AR , Wilkowski GM
Published: March 2009

Recent research on crack-tip constraint on fracture, including the effect of in-plane biaxial stress fields, has led to a two-parameter elastic K-T and elasto-plastic J-Q approach to correlate fracture toughness. These approaches predict a significant influence of biaxial stress state on fracture toughness. In the case of reactor pressure vessels undergoing pressurized thermal shock (PTS), significant stresses induced parallel to the crack front (out-of-plane stresses) offer additional constraint at the crack-tip. In order to evaluate the effect of this out-of-plane stress field on fracture of reactor pressure vessel steels, a unique method for testing a cruciform-type double-edge notch, DEN(T), specimen loaded in biaxial tension was developed. Three-dimensional finite-element analyses were conducted to design the specimen configuration. Details of the experimental and analytical results and the significance of the crack-tip constraint, due to biaxial stress state involving out-of-plane stresses, on the fracture toughness in the transition region are presented.
The Influence of Plasticity and Geometry on the Mixed Mode Fracture of PMMA
Authors: Davenport JCW , Smith DJ
Published: March 2009

The effects of changing notch tip constraint in mixed modes I/II, through the influence of plasticity and geometry, are studied in single edge notch (SEN) specimens of PMMA using a newly developed test apparatus. Elastic-plastic finite element analyses show the different constraint effects between notched and cracked specimens. The influence of molecular weight is also investigated. In a parallel study, the behaviour of PMMA under mixed modes I/III is studied using circumferentially notched round bar (CNRB) specimens. Two sizes of specimen, both notched, are tested to identify the role of constraint in this type of fracture. The results from both types of shear test show that the type of crack, mode of loading, and the load history all have an influence on the role of constraint and therefore its fracture properties of PMMA.
Constraint Effects on the Upper Shelf in Cracked Welded Specimens
Authors: Franco C , Gilles P , Eripret C , Nallet S
Published: March 2009

Assessing crack initiation in welds is of importance for pressure vessels, since in safety analyses cracks are usually postulated in weldments. The toughness that represents the material's resistance to crack initiation is measured on specimens. The transferability problem of this parameter to cracked welds in structures of different geometry and subjected to different type of loadings is investigated. Detailed inite element analyses are conducted on specimens exhibiting a high mismatch between base and weld metal tensile properties, ductile tearing initiation is predicted using three different approaches. One is the local approach, which models the growth of cavities in front of the crack, the two other are the two-parameter approaches referenced as J-T and J-Q, which describe the singular crack tip stress-stain fields with the amplitude of the singularity and a second order term. In comparison to homogeneous weld metal specimens, it is concluded that the constraint effect in bimetallic specimens remains unchanged if the distance of the crack tip to the interface is not too small with respect to the ligament size and if the initiation load is less than the yield limit load.
Effect of Squareness Tolerance on Charpy V-Notch Impact Energy
Authors: Marsh FJ
Published: March 2009

The need for a tight squareness tolerance (90° ±10 min) of adjacent sides of Charpy V-notch impact specimens has been questioned by Quality Assurance personnel in the metals industry. An experiment has been designed to evaluate the effect of the squareness tolerance greater than required in ASTM E23-93a, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials [1]. Material used to manufacture impact standards of low, high and super high energy levels was heat-treated, and the notched surface and surface opposite the notch were machined to 90° +20 min, 90° +40 min and 90° +60 min. The sides adjacent to the notch were held flat and parallel. A control set of samples was machined to meet current squareness requirements given in ASTM E 23. The results were statistically analyzed. The analysis shows when out-of-squareness is ⩾ 20 min, energy ranges, mean energy values and associated standard deviations at the low and high energy levels are statistically different when compared to the same information derived from SRMs.
The Optimization of Insert Size for Reconstituting Previously Tested Charpy Specimens
Authors: Williams JF , Shogan RP , Albertin L
Published: March 2009

The reconstitution of previously tested Charpy impact specimens via projection welding can be used to obtain additional data for nuclear reactor surveillance programs. Typically, a broken Charpy half contains a large portion of untested material. This untested material can be machined from a broken Charpy half to obtain an “insert.” “Endtabs” of similar material can then be welded to the insert. After the welded sample is machined to ASTM E23 specifications, it is then retested to obtain additional toughness data. The materials in this study show that 14 mm inserts can be successfully reconstituted and 10 mm inserts can be reconstituted with limited success.
Production of Charpy Impact Verification Specimens and Verification of Machine Performance
Authors: Hida N
Published: March 2009

In 1990, Japan established the industrial standard “Standard Specimens for Charpy Impact Testing Machines” and revised “Charpy Impact Testing Machines”. Before establishing these standards, the Iron and Steel Institute of Japan had studied the standardization of the reference test pieces and the reference testing machines. Reference test pieces for two energy levels (30 J and 100 J) are available, with a coefficient of variation within a lot of less than 4%.

Furthermore, the effect of non-uniformity of reference test pieces within a lot in the indirect verification have been examined. The verification test accuracy (estimation of the error and repeatability) is limited by the non-uniformity of test pieces within a lot.
Application of a Crack Length Measurement with a Laser Micrometer to R-Curve Tests
Authors: Legendre L , Journet B , Delmotte J , Millour G , Schwab J-M
Published: March 2009

The application of the damage tolerance philosophy to aeronautical thin structures requires that R-curves tests be run. The automation of such tests can be achieved through crack length monitoring using the compliance technique. However such a method faces experimental errors when a clipon gage extensometer is used to record the crack opening displacement on a CCT specimen because of the out-of-plane displacements. In order to write these displacements off, it is proposed to resort to a noncontacting device such as a scanning plane laser micrometer.

The sensor used consists of two parts which are symmetrically placed on each side of the central notch of the specimen. The emitter sends a 60 mm high laser plane wave to the receiver. Only the beams passing through the central hole of the specimen hit the receiver. The intensity of the transmitted laser beam is then converted into an electrical signal by the sensor electronics. A numerical processing of the signal enables a calculation of the crack opening displacement of a machined slot with a resolution greater than 1 μm and an excellent digital stability.

The measurement is then integrated into a PC microcomputer, which calculates the corresponding effective crack length using the appropriate compliance formula (ASTM E 561).

The stress intensity factor is computed from the testing machine load signal. A stability test (no crack growth under constant applied load step) is checked out in order to store the relevant data points for plotting the R-curve and to decide for the next load increment the computer is going to apply.

This laser technique was validated in comparison to a classical mechanical extensometer method on an aluminum alloy.

This method bears fruitful applications in testing under controlled environment (temperature, moist or corrosive atmosphere).
Assessing the Effectiveness of Slab Flooring as a Barrier to Soil Gas and Radon Infiltration
Authors: Williamson AD , Fowler CS , McDonough SE
Published: March 2009

Experimental studies on the entry of soil gas and radon into slab-on-grade buildings have been carried out in instrumented, single-zone test structures. This work, as part of the Florida Radon Research Program, focused on the effectiveness of slab flooring variants as barriers to soil gas/radon entry. A second objective was the study of the role of subslab fill soil as both a potential source of and barrier to radon entry. Studies were made in well-sealed (∼600 mm2 ELA) unoccupied test buildings placed on well-characterized, radium-bearing sandy fill soil. The buildings were instrumented with data acquisition systems to continuously monitor indoor radon concentrations, differential pressures at several subsurface locations, weather conditions, and soil moisture. The response of the structures to mechanical depressurization as well as natural driving forces was measured. Limited measurements were made regarding direct diffusive transport of radon through apparently intact concrete slabs, as well as transport through cracks in the floor structure.
Extraneous Air Leakage from Window Perimeters
Authors: Louis MJ , Nelson PE
Published: March 2009

The window industry has ratings for air leakage through window assemblies. These tests exclude air leakage from the joint between window and wall assemblies or from the sides of the windows. Such leakage is discounted by present window testing standards and labeled “extraneous air leakage.” Air leakage to the window perimeter can significantly effect the overall performance of the window/wall assembly.

A test methodology is presented for quantifying the portion of air leakage that is not measured by current industry standards, but that nonetheless is real and significant air leakage through some types of installed window assemblies.

Design guidelines are proposed to minimize air leakage through the window frame and around the window perimeter. This requires careful selection and detailing of the window and wall system to insure that the air barrier effectively seals to the window frame. These details must be carefully coordinated with the design of the flashing and cavity water-proofing, which have distinct and sometimes conflicting purposes. In three examples, the proper location for air barriers in different types of wall construction is identified along with methods to seal the air barreir to the window.
Time of Wetness and Dew Formation: A Model of Atmospheric Heat Transfer
Authors: Dean SW , Reiser DB
Published: March 2009

Time of wetness is a critical factor in atmospheric corrosion. Dew is a major contributor to time of wetness. In normal atmospheric exposures, dew formation is a result of radiative cooling of exposed surfaces below the dew point of surrounding air. The extent of radiational cooling of an object is affected by the effective sky temperature, the presence of clouds, the view of other surfaces at different temperatures, and air movement by wind or natural convection adjacent to the cooling surfaces. This paper models the temperature of a boldly exposed panel as a function of humidity and air current velocity. The model predicts a maximum panel temperature depression of approximately 16°C below ambient air temperature in still air. For wind velocities of 4.5 m/s (10 mph) radiational cooling lowers the panel temperature 3°C below ambient air temperature.
Evaluating the Durability of Sealants
Authors: Lacasse MA , Paroli RM
Published: March 2009

Five silicone based sealants were subjected to heat aging, humidity and ultraviolet radiation over an eight thousand hour period. Changes in the tensile characteristics of the sealant products were determined and investigated on the molecular level using infrared and thermoanalytical techniques. Tensile testing revealed that specimens subjected to direct UV radiation were, in certain instances more susceptible to loss in elongation capacity than when shielded from radiation. Furthermore, the reduced elongation capacities were dependent on sealant type with the largest losses in the order of 53%. There were also noticeable changes in the modulus with decreases of 40–70% and for one product, an increase of 43% after 8000 hours of accelerated aging. It is surmised that modulus decreases are due to chain scission; however, it was not possible to strictly verify this from the analytical work carried out in this study. However, TG/DTA did confirm the susceptibility to loss of PDMS as well as other sealant components at elevated temperatures. PAS-FTIR was instrumental in detecting the presence of absorbed water as well as filler modifiers, such as calcium carbonate treated with stearic acid, which potentially play a role in the change in mechanical properties of aged silicone products.
Dispersant Effectiveness: Studies into the Causes of Effectiveness Variations
Authors: Fingas MF , Kyle D , Tennyson E
Published: March 2009

Effectiveness, a key issue of using dispersants, is affected by many interrelated factors. The principal factors involved are the oil composition, dispersant formulation, sea surface turbulence and dispersant quantity.

Oil composition is a very strong determinant. Current dispersant formulation effectiveness correlates strongly with the amount of saturate component in the oil. The other components of the oil, the asphaltenes, resins or polars and aromatic fractions show a negative correlation with the dispersant effectiveness. Viscosity is also a predictor of dispersant effectiveness and may have an effect because it is in turn determined by oil composition. Dispersant composition is significant and interacts with oil composition. Dispersants show high effectiveness at HLB values near 10.

Sea turbulence strongly affects dispersant effectiveness. Effectiveness rises with increasing turbulence to a maximum value. Effectiveness for current commercial dispersants is gaussian around a peak salinity value. Peak effectiveness is achieved at very high dispersant quantities - at a ratio of 1:5, dispersant-to-oil volume. Dispersant effectiveness for those oils tested and under the conditions measured, is approximately logarithmic with dispersant quantity and will reach about 50% of its peak value at a dispersant to oil ratio of about 1:20 and near zero at a ratio of about 1:50.
COREXIT 9580 Shoreline Cleaner: Development, Application, and Status
Authors: Canevari GP , Fiocco RJ , Lessard RR , Fingas M
Published: March 2009

The cleanup of oiled shorelines has generally been by mechanical, labor-intensive means. The use of surfactants to deterge and lift the oil from the surface results in more complete and more rapid cleaning. Not only is the cleaning process more efficient, but it can also be less environmentally damaging since there is potentially much less human intrusion and stress on the biological community because chemicals can make washing effective at lower temperature. This paper will describe research on chemical beach cleaners for treatment of oiled shorelines that was initiated in support of the cleaning activities in Prince Willliam Sound (PWS) following the Valdez oil spill in March 1989.

The concept for using beach cleaners for shoreline cleanup is to apply a pre-soak to the weathered crude oil on shore and then flush with sea water to wash the oil into a boomed area for subsequent recovery. Criteria imposed on the use of chemical beach cleaners for the cleanup of the Valdez spill were: (1) effective rock cleaning agents should have very little or no toxicity to marine and terrestrial life, (2) there should be no dispersion of the oil washed from the shoreline into the water column; oil was to be recovered by techniques such as skimming or sorbents, and (3) the agents should be on the EPA National Contingency Plan (NCP) list.

A laboratory-scale rock washing test was developed to measure cleaner effectiveness and dispersion. A large number of commercially available formulated products were evaluated, as well as developmental formulations. The commercial products included all of the available NCP-listed products which could function as cleaners. None of the commercial products completely satisfied all the requirements established by the agencies for beach cleaning. However, a new formula, called COREXIT 9580, consisting of two surfactants and a solvent was developed. It exhibited low fish toxicity, low dispersancy and effective rock cleaning capability.

Although it was not approved for use in Alaska other than testing, subsequent work at ENVIRONMENT CANADA confirmed the outstanding cleaning effectiveness and very low toxicity of the new product, and it is currently on the approved product list in Canada.

The paper reviews the laboratory and field testing conducted to prove out this new product and highlights more recent work on mangroves to explore the potential use of COREXIT 9580 to save and restore oiled vegetation.
Space Transportation Main Engine (STME) Database Standardization
Authors: Lee JE , Jewett RP , Moore DR , Murphy AR , Horn RM , Funkhouser ME
Published: March 2009

The joint NASA/U.S. Air Force National Launch System (NLS) Space Transportation Main Engine (STME) Program utilized a government and contractor team to develop a common materials database system. A standardized materials data flow for the STME was constructed to allow raw materials property data with its pedigree to be captured and statistically reduced into design allowable properties with full traceability. The goal was to make the data flow as efficient and reliable as possible, while generating the required high-quality materials properties. To meet this goal, a systematic approach was applied to the database development that focused on establishing consensus standards and requirements. Key steps included the following: (1) conducting a Quality Function Deployment (QFD), (2) establishing requirements to drive the design allowable material properties, (3) deriving standard statistical methodology, (4) generating standard test procedures, (5) developing comprehensive standard data and analysis formats with automated data entry, and (6) establishing an approval agency to monitor the data acceptability.
Background and Basis for a Knowledge Elicitation Shell for Lifetime Predictions from Stress Corrosion Cracking Data
Authors: Roberge PR
Published: March 2009

An ideal expert system should closely reproduce the functions normally performed by the original source expert(s). But the complex transformation of a lifetime of industrial expertise into conveniently accessible software requires the willing and active participation of domain experts whose knowledge is rarely organized for such a transformation. The matching of logical and meticulous knowledge elicitation with memory-based judgments and expertise has often proved to be a difficult task. This paper describes an approach to construct a knowledge elicitation shell specifically adapted to the field of corrosion-related problems and expertise. The knowledge elicitation shell was structured along the lines of what has recently become the framework for the transfer of corrosion information to management and design engineers. The recent work published by Professor R. W. Staehle on the general topic of lifetime prediction and the impact of stress corrosion cracking on materials was used for this task. One obvious advantage of using an established formalism is the availability of supporting documentation and background material. The advantage of using Professor Staehle's work in particular is the clarity of his points of view that reflect a solid career in materials science and engineering. In this paper, the environment-induced cracking of high-strength aluminum alloys is used as an example to illustrate how the elicitation shell could be activated. It is believed that, by using the elicitation shell, human experts will have to rationalize some aspects of their expertise and subsequently become able to establish new links between facts and corrosion data. The process of building tables of certainty factors during the shell operation and interaction with users is also discussed.
A Software Tool for Material Data Analysis and Property Prediction: CASAC-ANA
Authors: Zhou J , Xie Q , Feng J , Li S , Xu Z , Chen L , Gui Z
Published: March 2009

In this paper, a user-friendly software, CASAC-ANA, for material data analysis and property prediction is presented. In CASAC-ANA, there are seven methods: Nonlinear Mapping (NLM), Principal Component Analysis (PCA), Stepwise Discriminant Analysis (SDA), Discriminant Analysis with Constellation Graph (DACG), Hierarchical Clustering Analysis (HCA), Stepwise Multiple Linear Regression (SMLR), and Artificial Neural Networks (ANN).

The software has some noteworthy features: (1) only one input file is needed and multipath output is produced; (2) both quantitative and qualitative data of dependent variables are accepted; and (3) it is easy to link with materials property databases. As a generalized modeling tool, CASAC-ANA can be used to treat material data concerning composition, technological processes, properties, and to predict properties of materials.

The validity of the CASAC-ANA software has been tested successfully with three typical case studies concerning structural alloy steels, nickel-base superalloys, and continuously cast copper alloys. These CASAC-ANA methods have been compared and discussed.
Matching Information Technologies with the Objectives of Materials Data Users
Authors: Begley EF , Sturrock CP
Published: March 2009

During the last decade, information technologies have become broadly and deeply integrated with the ways in which we all work. In large part, this is due to the phenomenal distribution of personal computers, but the evolution of the software that makes computers do useful work has also played an important role. One recalls the early 1970s when database management system (DBMS) software, for example, was considered exotic and unreliable, whereas it is now regarded as stable and mundane. During this symposium, we heard about other information technologies that, at first, seem exotic: neural networks, hypermedia, expert systems, and object-oriented databases. This paper will examine these technologies and provide some examples of how they are being applied to the problems that users of materials data are working to solve.
Performance-Based Properties of Asphalt Concrete Mixes
Authors: Leahy RB , Monismith CL , Lundy JR
Published: March 2009

Key objectives of the Strategic Highway Research Project (SHRP) A-003A were to validate properties selected for inclusion in the binder specification and to develop accelerated performance tests (APTs) suitable for predicting pavement performance in terms of fatigue and low temperature cracking as well as permanent deformation. This paper specifically addresses the laboratory tests, measured engineering properties and their relationship to the SHRP binder specification and to performance for both unmodified and modified mixes.

Materials considered in this research included 8 to 16 binders, 5 modifiers, and 2 to 4 aggregates. For fatigue, mixes were tested in the controlled-strain mode of loading using a flexural beam test device. For permanent deformation both a wheel-tracking device and a simple shear repeated-load test apparatus was used. Low temperature thermal cracking was evaluated using the thermal stress restrained specimen test (TSRST).

Overall, the results indicate that the relationship between binder properties and mix performance, as measured by the recently developed APTs, is excellent for thermal cracking, but substantially less definitive for fatigue cracking and permanent deformation. Furthermore, the recently developed APTs and resulting engineering properties are suitable for predicting pavement performance of modified mixes as well.
Analysis of a Well-Performing Desert Pavement
Authors: Sebaaly P , Thirmarayappa V , Epps J , Quilici L
Published: March 2009

A flexible pavement project located in the southern part of the state on I-15 near Las Vegas was selected for this investigation. The pavement section consists of an overlay that was constructed in 1970. Twenty two years later, this pavement is still showing excellent performance under the severe weather conditions and heavy traffic loading. As part of this investigation, slabs and cores were cut from the pavement section and laboratory tests were conducted on the various materials. The rheological properties of the recovered asphalt binder were evaluated and compared to the newly developed SHRP specifications. The properties of mixtures that were evaluated included the following: In situ air voids, resilient modulus at various temperatures, moisture sensitivity, and permanent deformation characteristics. The extracted aggregates were also tested for any degradation and their gradation curves were compared to the FHWA and SUPERPAVE recommendations.
Use of Bathymetry for Sediment Characterization at Indiana Harbor
Authors: Petrovski DM
Published: March 2009

In 1992, U.S. EPA, Region 5, sampled sediments within the Federal Navigation Project at Indiana Harbor, IN. Lack of a disposal site has precluded dredging since 1972, resulting in the accumulation of over 750 000 m3 of highly contaminated sediment. The Federal Project covers approximately 1.08 km2 of both enhanced and secondary sediment accumulation. The purpose of the sampling effort was to characterize these sediments under Subtitle C of the Resource Conservation and Recovery Act (RCRA). Several approaches common to regulatory characterization were considered and rejected in favor of a bathymetry based procedure. Bathymetric surveys were used to identify 14 areas of thick sediment accumulation. Such areas are indicative of reduced water velocities which favor the accumulation of finer-grained sediment having a strong tendency to be associated with higher contaminant concentrations. Samples obtained from these locations should contain contaminant concentrations that exceed the mean concentrations for the project sediments. Consequently, a regulatory decision based upon these samples should be conservative. Bathymetry may provide a mechanism to reduce the number of samples necessary to characterize large sediment volumes, while maintaining an acceptable level of confidence in any derived regulatory decision.
Demonstrations and Commercial Applications of Innovative Sediment Removal Technologies
Authors: Pelletier J-P
Published: March 2009

The Contaminated Sediment Removal Program (CSRP) of Environment Canada was founded in November 1990 following a request from the Great Lakes Cleanup Fund to the Environmental Protection Service-Ontario Region to provide leadership in the identification of removal technologies and procedures for contaminated sediments in the Great Lakes.

Following a request for proposal issued by the CSRP, proposals were received from vendors of innovative sediment removal technologies to conduct contaminated sediment removal demonstrations in different Areas of Concern (AOCs) on the Canadian side of the Great Lakes.

In 1992, the CSRP conducted the demonstration of two innovative sediment removal technologies at three different sites. The Cable Arm 100E clamshell bucket was demonstrated in Toronto and Hamilton Harbours, while the Pneuma Pump was demonstrated in Collingwood Harbour.

Those three demonstrations led to the first Canadian commercial applications of the Cable Arm 100E clamshell bucket in Pickering, Ontario, and of the Pneuma Pump in Collingwood, Ontario.
Development of Solidification Technique for Dredged Sediments
Authors: Yamasaki S , Yasui H , Fukue M
Published: March 2009

The sediments deposited on the bottoms of seas, lakes, and rivers can be contaminated with hazardous and toxic substances as a result of the discharge of human activities. Therefore, since the natural remediation process cannot be expected, contaminated or polluted as well as highly organic sediments must be treated as waste and be properly disposed for human health and environmental protection.

One method of disposal may be to remove the sediments by dredging and to treat them with a proper technique. The main problems in the dredging method are as follows: 1) Since sediments usually have very high water content, it is necessary to decrease the volume and solidify them for the next procedure, e.g., landfill. (2) The leachates from the sediments should be treated also. It is required that the water to be discharged be kept at a quality satisfying “the level of standards.”

This paper describes an experimental study using a solidification system performed for the cleanup of the bottom of a river. To promote the solidification of the system, several agents, such as lime, cement, polymer, resin, etc., were used. The results show that these agents strongly influence the solidification characteristics of the sediments and the quality of the leachate from the sediments.
New In-Situ Procedures for Measuring Trace Metals in Pore Waters
Authors: Zhang H , Davison W , Grime GW
Published: March 2009

The most mobile and biological and chemically active fractions of trace metals in sediments are the dissolved components present in pore waters. Measuring metals in pore waters is complicated by the requirement for anoxic handling procedures. Due to the dynamic nature of sediment, steep concentration gradients extending over as little as 1 mm may develop at the sediment-water interface. New procedures for measuring metals in pore waters using polyacrylamide gels as in-situ probes are described. The gel can be used to establish a diffusive equilibration in a thin-film (DET). Because the film is typically less than 1 mm thick, equilibration is achieved within five minutes and insertion of the gel assembly causes minimal disturbance of sediment. An alternative procedure is to use a diffusive gradient in a thin-film (DGT), whereby a monolayer of chelating resin is incorporated at one side of the gel. Such a technique provides a kinetic measurement of labile species in solution. If the supply of metal from solid phase sediment to pore waters is fast enough, DGT provides a quantitative estimate of labile metal concentration. Alternatively, it measures directly the rate of supply of metal from solid phase to pore waters. As both DET and DGT are simple procedures capable of submillimetre spatial resolution, they provide previously unobtainable information on trace metal concentrations and fluxes. Furthermore, DGT has the potential to be used as a long-term monitor, providing mean concentrations of metals in sediment pore waters over periods of days, weeks, or even months.
Mercury-Contaminated Sludge Treatment by Dredging in Minamata Bay
Authors: Yoshinaga K
Published: March 2009

To eradicate Minamata Disease, caused by the discharge of sewage containing methyl mercury and its accumulation in fish and shellfish through the food cycle, a large-scale sediment disposal project was conducted with special care taken to prevent new pollution resulting from the project itself. The basic approach to sediment disposal was to construct a highly watertight revetment to reclaim the inner area of the bay and then confine sediment dredged from the remaining contaminated area in the reclamation area through surface treatment. Before sediment disposal, boundary nets were installed to enclose the work area to prevent the mixing of contaminated and noncontaminated fish. Dredging work was successfully carried out by using four cutterless suction dredgers, newly developed in advance for minimizing resuspension of sediments. Dredged material was discharged into the reclamation area, filled up to sea level, and covered with a sandproof membrane, lightweight volcanic ash earth, and mountain soil.
State of the Art: CDF Contaminant Pathway Control
Authors: Richardson GN , Petrovski DM , Chaney RC , Demars KR
Published: March 2009

Contaminants from sediments contained within a confined disposal facility (CDF) can be discharged to the environment via six potential pathways. These pathways include three waterborne pathways, the direct uptake of the contaminants by plants or animals, and airborne emission of contaminants. Conventional CDF design focuses on retention of sediment particles with perimeter dikes. Depending upon the nature of the site, the contaminants of concern, method of dredging, physical properties of the dredged material, operational aspects, and many other factors, including sociopolitical factors, supplemental environmental design criteria may be required for the CDF. This paper reviews design alternatives to control contaminant loss from the CDF basin through the six identified contaminant pathways. These alternatives include the use of both additional design components and operational constraints. The need for a specific pathway control measure is shown to depend on both site and sediment specific evaluation criteria.
Orientation Effects on the Measurement and Analysis of Critical CTOA in an Aluminum Alloy Sheet
Authors: Sutton MA , Dawicke DS , Newman JC
Published: March 2009

Fracture tests were conducted on 76.2mm wide, 2.3mm thick middle crack tension (M(T)) specimens machined from 2024-T3 aluminum sheet. The specimens were tested in the T-L orientation and comparisons were made to similar tests conducted in the L-T orientation. Measurement of critical crack tip opening angle (CTOA), applied stress, and crack front shape were made as a function of crack extension. A two-dimensional, elastic-plastic finite element analysis was used to simulate the fracture behavior for both orientations. The results indicate that the T-L orientation had a 10% lower stress at fracture than similar tests conducted in the L-T orientation. Correspondingly, the critical CTOA in the T-L tests reached a constant value of 4.7° after 2–3mm of crack extension and the L-T tests reached a value of 6°. The fracture surface of the T-L specimens were observed to remain flat, while those of the L-T specimens transitioned to a 45° slant fracture after about 2–3mm of crack extension. The tunneling behavior of the two orientations also differed; the T-L specimens reached a deeply tunneled stabilized crack front shape, while the L-T specimens were observed to have only a small amount of tunneling once the crack began to grow on the 45° slant. The two-dimensional, elastic-plastic finite element analysis was able to simulate the fracture behavior for both the T-L and L-T orientations.
Evaluation of Disk-Shaped Compact Specimen for Determining J-R Curves
Authors: Yoon KK , Gross LB , Wade CS , VanDerSluys WA
Published: March 2009

A set of equations are developed for a disk-shaped compact (DC(T)) specimen to be used in conjunction with ASTM E 1152-87 standard which is for determining J-R curves using rectangular compact specimens. A slightly different disk-shaped tension specimen design (BWDC(T)) is used by B&W Owners Group in their Integrated Reactor Vessel Material Surveillance Program [1] (IRVSP). This specimen is analyzed by a finite element method to investigate whether the standard DC(T) compliance relationship is appropriate for use. Validation tests using both square C(T) and DC(T) specimens were performed and the resulting J-R curves are compared. It is concluded that using this procedure both C(T) and BWDC(T) specimens yield similar J-R curves.
Stress-Intensity-Factor Influence Coefficients for Semielliptical Inner-Surface Flaws in Clad Pressure Vessels
Authors: Keeney JA , Bryson JW
Published: March 2009

A problem of particular interest in pressure vessel technology is the calculation of accurate stress-intensity factors for semielliptical surface cracks in cylinders. Computing costs for direct solution techniques can be prohibitive when applied to three-dimensional (3-D) geometries with time-varying boundary conditions such as those associated with pressurized thermal shock. An alternative superposition technique requires the calculation of a set of influence coefficients for a given 3-D crack model that can be superimposed to obtain mode-I stress-intensity factors. This paper presents stress-intensity-factor influence coefficients (SIFICs) for axially and circumferentially oriented finite-length semielliptical inner-surface flaws with aspect ratios [total crack length (2c) to crack depth (a)] of 2, 6, and 10 for clad cylinders having an internal radius (Ri) to wall thickness (t) ratio of 10. SIFICs are computed for flaw depths in the range of 0.01 ≤ a/t ≤ 0.5 and two cladding thicknesses. The incorporation of this SIFIC data base in fracture mechanics codes will facilitate the generation of fracture mechanics solutions for a wide range of flaw geometries as may be required in structural integrity assessments of pressurized-water and boiling-water reactors.
Evaluation and Significance of Fracture Toughness in Ceramic Materials
Authors: Mutoh Y
Published: March 2009

Fracture toughness tests of several ceramic materials were carried out according to the various test methods, that is the Bridge indentation(BI, SEPB), Fatigue precrack(FP), Controlled surface flaw(CSF), Chevron notch(CN) and Indentation fracture(IF) methods. Mutual comparison of the test results was made to discuss the validity and applicability of the each test method. Significance of the apparent fracture toughness with stable crack growth was discussed. The intrinsic fracture toughness can be obtained by the CSF method, in which a small surface crack is used. At high temperatures, since nonlinear deformation due to softening of glass phase and stable crack growth occur, nonlinear fracture mechanics approach should be applied. JIC-value is successfully evaluated according to the R-curve method.
Numerical Modeling and Experiments of Creep Crack Growth Under Cyclic Loading
Authors: Brust FW
Published: March 2009

This paper presents a summary of some recent studies of creep crack growth under history dependent load conditions. The effect of a proper constitutive law is illustrated. Moreover, the asymptotic fields are reconsidered under cyclic creep conditions. In addition, several experiments are modeled and the behavior of integral parameters is discussed.
Intermittent Environment-Assisted Crack Growth During Slow Constant Extension Rate Testing
Authors: Webb TW , Meyn DA
Published: March 2009

The slow constant extension rate (CER) test using fatigue precracked fracture specimens offers advantages over the conventional static (fixed displacement and constant load) tests. It generally requires fewer specimens and shorter test times to determine the threshold for crack initiation. However, apparent anomalies in the subcritical crack growth kinetics have been observed, which complicate the interpretation of the CER test measurements. Oscillations in the crack velocity occur resulting in macroscopic intermittent crack growth and periodic fluctuations in the applied load. An analysis of the CER test applied to environment-assisted cracking (EAC) is made and a phenomenological model is proposed to describe the mechanics of macroscopic intermittent crack growth. As a result of the analysis, the oscillations in the crack velocity are found to depend on the elastic behavior of the specimen and loading system and the aggressiveness and activity of the environment at the crack tip.
Introduction of δ5 as an Operational Definition of the CTOD and Its Practical Use
Authors: Schwalbe K-H
Published: March 2009

A number of years ago δ5 was introduced as an experimental technique for determining the crack tip opening displacement. Experience gained since then has confirmed that δ5 can be used as an operational definition of the CTOD which has the advantage that due to its direct measurement without the need of calibration functions, it can be measured on any cracked part, be it a test specimen or a structural component. In the case of bend bars δ5 is closely linked to standardised test methods. It is also shown that δ5 is uniquely related to the J-integral and that it can be predicted as a driving force parameter with the Engineering Treatment Model, allowing the use of δ5 in flaw assessments.