bluuebunny/crossref_metadata_2025 huggingface dataset:
A Full Field DC Potential Drop Calibration for an Asymmetrically Cracked M(T) Specimen
Authors: McKeighan PC , Zhu W-X , Smith DJ
Published: February 2009

A direct current (DC) potential drop (PD) calibration tool, in the form of a computer program, is provided that can determine the PD response at any point in an M(T) specimen containing either a symmetric or asymmetric crack. Results from the program were verified using data in the literature and results from an analog simulation. If a standard PD calibration is applied to the PD response for an asymmetric crack, the total crack length will be underestimated which leads to significant stress intensity factor errors for even small amounts of asymmetry. Using the PD response of an asymmetric crack from an analog simulation, three methods to predict individual crack lengths are evaluated. The methods use a two-dimensional (2-D) iterative procedure to solve for crack length given voltages from at least two sets of probes located at different positions on the specimen. Any of the different methods, which use different probe locations as the calibration inputs, yield good crack length predictions for crack length to specimen width ratios a/W greater than 0.25. However, the most numerically robust method resulting in the least error over a large crack length range uses the PD from a centerline probe and the PD difference from two offset probes to predict the crack length. These predictions result in a crack length error that does not exceed ±0.004 W and consequently result in insignificant stress intensity factor errors.
A Quantitative X-Ray Diffraction Technique for Analyzing Sedimentary Rocks and Soils
Authors: Burnett AD
Published: February 2009

Mineralogical studies of sedimentary rocks or sedimentary deposits are often required for engineering geological projects. X-ray diffraction analytical techniques are usually employed for this purpose but these methods are often complex and involved. Several different X-ray diffraction methods are described and a single suitable procedure is chosen and described in detail. The chosen method includes analysis of both clay and non-clay minerals and qualitative and quantitative interpretation.
TOFSIMS Studies of Cleaning Procedures and Silane Surface Treatments of Steels
Authors: Sabata A , Knueppel BA , van Ooij WJ
Published: February 2009

Surface contaminants can affect properties such as wet-tability and reactivity in subsequent surface preparation processes. Cleaning of metal substrates has usually been studied by techniques such as AES and XPS. These techniques do not give any information on the molecular structure of the contaminants; however, Time-of-Flight Secondary Ion Mass Spectrometry (TOFSIMS) with its monolayer sensitivity, has been effective in providing structural, molecular information of organic contaminants which may be useful in identifying the source of the contamination.

Industrial alkaline cleaning and degreasing processes leave mainly a siloxane-type of contaminant that deteriorates the adhesion of metals to epoxies. Phosphating leaves the surface clean and microrough, which improves the adhesion of adhesives to cold-rolled steel (CRS). Epoxies when cured at high temperatures give better adhesion values as compared to room temperature epoxies.

Organofunctional silanes such as styrylamino aminopropyltrimeth-oxysilane (SAAPS) were found to have a specific orientation on the metal substrate as a function of cleanliness and mode of application. The orientation of the vinylbenzyl group towards the epoxy adhesive is shown to improve adhesion. A combined silicate and silane post-rinse of phosphate coatings is shown to be effective in giving the silanes the required orientation for bonding to epoxies, thus improving the adhesion.
A Thermal Control System for Thermal Cycling
Authors: Hartman GA
Published: February 2009

A microprocessor-based system has been developed to control varying temperature during material characterization tests. The system controls temperature independently over four zones. Four control zones are used in order to provide two-dimensional temperature control on a flat plate specimen. Specimen cooling is provided by forced air through shower head type nozzles.
A New Method forIn SituCompliance Measurements for Fatigue Crack Growth Testing in Autoclaves
Authors: James LA , Ceschini LJ
Published: February 2009

A new method has been developed for in situ compliance measurements on fatigue crack growth specimens. Crack lengths may then be inferred from the compliance measurements. The method is particularly well suited for autoclave testing where direct observation of the specimens is impossible. The new method uses the change in induced eddy current fields with specimen loading as a measure of specimen compliance. Calibration of the device in various environments and temperatures is discussed.
Design and Use of a Load Monitoring Environmental Test Chamber for Stress Corrosion Testing
Authors: Shaw BJ
Published: February 2009

This paper gives the construction details and materials used to make an environmental test chamber for stress corrosion cracking tests in which the load on the specimen can be continuously monitored. The design is such that 1T, 0.75T, and 0.5T CT and WOL specimens can be tested in most environments up to pressures of 0.8 MPa (100 psig) and in the temperature range of 0 to 100°C. The apparatus can be used to measure the stress intensity K and the crack length in a test specimen at any time. Consequently crack growth rate as a function of applied stress intensity and the threshold stress intensity KIscc can be obtained. A conceptual compromise in the design stemmed from the requirement of (1) a highly rigid loading system to simulate a bolt load test, and (2) the inclusion of a reasonably sensitive, low rigidity load cell in the loading train. In order to optimize the design, the load cells manufactured at the Westinghouse R&D Center were carefully evaluated. It was concluded that conventional strain gages are sensitive to the local environment (temperature and humidity) and that considerable care is required to limit errors in long term measurements.
Austenitic Iron-Aluminum-Manganese Alloys As Possible Substitutes for Austenitic Stainless Steels
Authors: Heger JJ
Published: February 2009

Alloys of iron-aluminum-manganese containing over 8% aluminum can be made completely austenitic and have good ductility and toughness. Oxidation resistance is good at temperatures up to 982°C (1800°F), but embrittlement occurs following heating in the range 538 to 760°C (1000 to 1400°F). Resistance to corrosion by aqueous environments is poor.
An Experimental Sieving Machine
Authors: Carter AC
Published: February 2009

Sieving by hand is tedious but can be the most consistent of the available methods of sieve analysis. Segregation, particularly of materials having irregularly shaped particles, produced by generally available machines is seldom completely in agreement with hand sieving results. Moreover, gradings produced by different machines often differ significantly from one another.

Sieving machines, generally, are vibratory at low amplitude, with overdamped action at a frequency in the sonic range. An alternative mechanical system is described that is vibratory at infrasonic frequency, with minimal damping and high amplitude. By a suitable choice of component values a resonant simple harmonic motion causes a tossing action at a frequency of 6 to 8 Hz. This action produces results not less consistent than those obtained with hand sieving.

A number of benefits accrue from the system described herein.
Interlaboratory Evaluation of ASTM Practice for X-Ray Determination of Retained Austenite in Steel with Near-Random Crystallographic Orientation (E 975)
Authors: Hinton RW
Published: February 2009

A standard practice (ASTM E 975) was developed by Task Group E04.0602 for the X-ray diffraction determination of retained austenite in steel. Results of interlaboratory studies of retained austenite samples performed before and after the practice was developed are described. The final interlaboratory study using ASTM E 975 and ASTM E 173 as a guide to the study resulted in an estimate of repeatability within the same laboratory of 3% retained austenite for a 95% confidence limit, and an estimate of reproducibility between laboratories of 4% retained austenite for a 95% confidence limit.
Improved Impulse-Frequency Response Techniques for Measurement of Dynamic Mechanical Properties of Composite Materials
Authors: Suarez SA , Gibson RF
Published: February 2009

The dynamic mechanical properties of composite material specimens are rapidly determined by using two new computer-aided impulse techniques. Small beam specimens are excited in either flexural or extensional vibration by an electromagnetic hammer with a force transducer in its tip, while specimen response is measured with an eddy current probe or accelerometer. A desktop computer/Fast Fourier Transform analyzer system is then used for rapid data acquisition and computation of the complex modulus by curve-fitting to the frequency response function.
An Operational Procedure for Guarded Hot Box Testing
Authors: Gerace RR , Derderian GD , Cirignano PC , Orlandi RD , Shu LS
Published: February 2009

An operational procedure for guarded hot box (GHB) testing has been developed in the Thermal Measurements Laboratory (TML) of the Construction Products Division of W. R. Grace and Co. The GHB operational procedures consisting of specimen preparation, “calibration”, testing, data analysis, and reporting are presented in this report. These procedures follow the general guidelines given in ASTM Test for Steady-State Thermal Performance of Building Assemblies by Means of a Guarded Hot Box (C 236). In the specimen preparation procedure, material handling, specimen construction, specimen mounting into the specimen frame, and instrumentation placement and method of attachment are discussed in detail. The “calibration” procedure developed accounts for any variations in the thermal conductance of the metering box walls caused by design or construction. The experimentally determined setting for the thermopile electromotive force is controlled during testing so that the net heat flow through the metering box walls is negligible. The “calibration” procedure does not require knowledge of the thermal conductance of the specimen. A testing procedure is discussed that provides steady-state operation as defined by six steady 4-h periods of temperature and heat flow data within 1% of each other. The test data are analyzed and a GHB test report is generated by a computer software package. Examples of a typical GHB test report and a testing procedure data sheet are presented.
Measuring Thermal Performance of Wall Assemblies under Dynamic Temperature Conditions
Authors: Van Geem MG
Published: February 2009

The calibrated hot box (ASTM Test for Thermal Performance of Building Assemblies by Means of a Calibrated Hot Box [C 976]) is used to measure thermal performance of wall assemblies under dynamic temperature conditions. ASTM C 976 does not specify procedures for dynamic testing, or analysis and presentation of results. Dynamic testing procedures used by Construction Technology Laboratories (CTL), including instrumentation of test specimens, derivation of dynamic temperature cycles, acquisition of test data, and presentation of results, are described in this paper. Since 1979, CTL has applied dynamic temperature cycles to 25 wall assemblies using the calibrated hot box.

Thermal lag, reduction in amplitude, and the total heat flow ratio are three coefficients used by CTL to describe test specimen behavior under dynamic temperature conditions. These coefficients are derived from comparisons of measured results to values predicted by a steady-state analysis. Thermal lag, reduction in amplitude, and the total heat flow ratio characterize effects of thermal storage capacity. Derivation, usefulness, and limitations of these dynamic heat transmission coefficients are discussed.
A Proposed Test Procedure for the Evaluation of Air Barrier Systems
Authors: Timusk J , Seskus AL
Published: February 2009

A method for evaluating the performance of air barrier systems for building enclosures is described. It is proposed that two identical enclosure elements be placed back-to-back and, for airtightness purposes, be joined to each other by the same techniques which join the element to the structure itself. This way, by taking advantage of symmetry, virtually all joints not found in actual applications can be eliminated, barring easy-to-seal joints associated with air supply or exhaust and pressure tap lines. Three applications of the approach with associated test results are presented. It is suggested that the proposed test procedure has the following advantages over single-specimen tests in conjunction with a test chamber: specimen size and shape are not restricted, samples can be saved for future testing after suitable aging procedures, specimens can be tested outdoors or in a controlled environment chamber, and virtually all extraneous joints can be eliminated. A disadvantage is that two specimens may have to be prepared.
A Method for Determining the Tensile Properties and Anisotropy of Aluminum Alloys
Authors: Srivatsan TS , Meyers CW , Berry JT
Published: February 2009

Current industrial design practices place emphasis on properties in order to ensure that a product provides structural integrity. Mechanical properties are largely influenced by the direction of testing with respect to the wrought microstructure. In aluminum alloys the properties sensitive to direction are strength, ductility, and fracture toughness. In this study, the Double Ligament Tensile (DLT) test was used to evaluate the tensile properties and anisotropy of premium quality cast hypoeutectic and hypereutectic aluminum-silicon alloys of cylindrical cross section, and age-hardened commercial wrought aluminum-magnesium-silicon and aluminum-zinc-magnesium plates of limited section thickness. Comparisons reveal that the DLT test results accord well with standard conventional test data. The difference in tensile properties observed with direction of testing is attributed to the well-developed mechanical fibering that exists in the wrought alloys examined. The transverse brittleness observed in these alloys is due to the presence of particle stringers, grain boundary precipitates, and unhealed porosity.
Thermoelectric Differences Used for Metal Sorting
Authors: Stuart CM
Published: February 2009

Thermoelectric or Seebeck effect devices are beginning to see wide-spread use in metal and alloy sorting and verification processes, prompting the recent approval of ASTM Practice for Thermo-electric Sorting of Electrically Conductive Materials (E 977). This paper briefly explores the history of its use and discusses the theory of the method, while focusing deeper attention on practical applications of the devices and areas of its limitations. Testing requirements, specific material separations and examples, variables, advantages, disadvantages, and traceability are highlighted.
Evaluation of Intergranular Fracture Initiation in Transition Region of Retired Steam Turbine Rotor Steel Using Small Specimens and the Acoustic Emission Technique
Authors: Shimomura K , Shoji T , Takahashi H
Published: February 2009

Fracture toughness tests were performed at 150°C in the transition region for a Cr-Mo-V steel using four different sizes of compact tension specimens and with the use of the acoustic emission (AE) technique. Two fracture toughness parameters were obtained to evaluate the intergranular mode fracture toughness: one is the critical fracture toughness of KJC calculated from Jc, the other is a fracture toughness of KJAE characterized by the onset of microscopic pop-in cracking determined by AE. The values of KJC and KJAE of the smaller specimens show a great deal of scatter. Combining the fractographic studies, the source of toughness scatter is discussed in terms of the loss of plastic constraint. The results show that the lower bound values of KJAE in the smaller specimen sizes are coincident with a valid fracture toughness, KIC(AE), of the large specimen. An accurate evaluation of the intergranular mode fracture toughness is also discussed.
Computerization of the NBS Smoke Chamber with a Microcomputer and an A/D Converter
Authors: Eichhorn RM , Barrow WL , Davis DA
Published: February 2009

The most common and popular way to determine the amount of smoke generated during combustion of materials, including electrical insulations, is to measure the decrease in light transmission due to the accumulation of smoke in a closed chamber. The test equipment most used for this purpose today is the commercially available NBS Smoke Density Chamber.

Since the first published description of this apparatus in 1967 [1] several modifications to the chamber have been suggested and alternative methods for analysis of the data obtained have been proposed. Some have been evaluated and a few adopted, but in general they have tended to make the operation and analysis more time consuming and complex.

In order to (1) simplify operation, (2) improve precision, and (3) automate data reduction, the complete procedure has been computerized. This includes operation of the chamber, range changing of the photometer, insertion and withdrawal of the optical filter, accumulation of light transmission values as a function of time, and subsequent calculation and printing of smoke parameters. Replicate specimens are used and corrected specific optical density results can be previewed, truncated if necessary, and averaged. The final data are stored on disk in the Data Interchange Format (DIF) for subsequent use in graphics plotting programs.

An APPLE II Plus computer with an ISAAC interface (Integrated System for Automated Acquisition and Control) manufactured by Cyborg Corporation is used for data collection, reduction to optical density, and analysis. Software is written in BASIC. A specially designed electromechanical system which contains relays for photometer range changing and a small motor for moving the filter operates upon signals from the computer. The standard NBS parameters (Ds after various times, Dm (corr), and times to reach specified values of Ds) are printed as well as SOI, SI, and MOD [1–4].

An estimate of overall test precision and a few typical test results are presented, although they are not intended to reflect or predict possible or relative hazards of any material under actual fire conditions.
Stress Analysis of the Cracked-Lap-Shear Specimen: An ASTM Round-Robin
Authors: Johnson WS
Published: February 2009

An ASTM round-robin was conducted to evaluate the state of the art in stress analysis of adhesively bonded joint specimens. Specifically, the participants were asked to calculate the strain-energy-release rate for two different geometry cracked-lap-shear (CLS) specimens at four different debond lengths. The various analytical techniques consisted of two- and three-dimensional finite element analysis, beam theory, plate theory, and a combination of beam theory and finite element analysis. The results were examined in terms of the total strain-energy-release rate and the Mode I to Mode II ratio as a function of debond length for each specimen geometry. These results basically clustered into two groups: geometric linear or geometric nonlinear analysis. The geometric nonlinear analysis is required to properly analyze the CLS specimens. The three-dimensional finite element analysis gave indications of edge closure plus some Mode III loading. Each participant described their analytical technique and results. Nine laboratories participated.
Near-Threshold Fatigue Crack Growth Behavior for 316 Stainless Steel
Authors: Mills WJ , James LA
Published: February 2009

Fatigue crack growth threshold behavior of Type 316 stainless steel was studied in air at 24°C to evaluate the effects of load-shedding rate and specimen geometry on ultra-low crack growth rates. Load-shedding rates greater than the maximum rate recommended in the proposed ASTM test procedure were found to have no substantial effect on the threshold behavior. At very low ΔK levels, crack growth rates were apparently dependent on environmental effects and the degree of plastic constraint.
Monitoring of Oxide Layer Thickness on Zircaloy-2 by the Eddy Current Test Method
Authors: Sinha AK , Shah BK , Kulkarni PG
Published: February 2009

To ensure adequate wear resistance on some of the nuclear reactor components made of Zircaloy-2, a uniform thick buff oxide layer is desirable. Commonly used methods to evaluate oxide thickness (i.e., metallography and weight gain) have certain limitations. In this paper, results of eddy current (ECT) monitoring as a function of oxide layer thickness (determined metallographically) on Zircaloy-2 surface have been reported. A linear correlation between ECT response and oxide layer thickness has been established.
J-Integral Testing of Aluminum Alloys: A New Technique for Marking Crack Fronts
Authors: Beaver PW
Published: February 2009

An important aspect of the standardized JIc test method is the measurement of the amount of crack extension as a function of load. The usual method of marking crack fronts for subsequent measurement in a luminum alloys is to fatigue cycle after initial static crack extension.

In this paper, a new technique for marking crack fronts in aluminum alloys is described. This new technique, based on liquid metal embrittlement of grain boundaries in aluminum by gallium, is, for the alloys examined in this work, a more effective method of crack front marking than fatigue cycling.
Determination of Material Characteristic Values in Elastic-Plastic Fracture Mechanics by Means ofJ-Integral Crack Resistance Curves
Authors: Roos E , Eisele U
Published: February 2009

This article discusses the problem of determining the characteristic values in ductile fracture mechanics on the basis of the J-integral. Special interest is directed towards the question of transferability of the characteristic values from laboratory specimens to large-scale specimens of dimensions similar to those of components.

For this purpose technical substitute values and physical crack initiation characteristic values were determined from a number of specimens and a wide range of materials, showing the effect of material toughness and specimen geometry on the characteristic values. Technical substitute values were determined per ASTM (JIc), Loss et al. (J0.15), and Schwalbe and Heerens (J0.2). Determination of the physical crack initiation value resulted from measurements of the stretched zone.

The technical substitute values and the physical crack initiation values were compared with results for large-scale specimens. Only the physical crack initiation value (Ji) correctly described the behavior of large-scale specimens regarding crack initiation.
A Dynamic Microindentation Apparatus for Materials Characterization
Authors: Polvani RS , Ruff AW , Whitenton EP
Published: February 2009

A microindentation system is described that provides a new approach to dynamic mechanical testing. The indentation is characterized in terms of continuous measurements of applied load and penetration depth. The indentation can be performed over a wide range of loading times from hours to milliseconds. The shape of the loading waveform can also be selected. The deformation energy can be measured and partitioned into elastic, plastic, and anelastic components. The apparatus is also able to perform conventional hardness testing, and may be useful for estimating conventional mechanical properties.
On the Analysis of Thermally Activated Tension-Tension Cyclic Deformation Behavior
Authors: Mshana JS , Krausz AS
Published: February 2009

The application of the transition state theory of rate processes to describe tension-tension cyclic deformation behavior was reviewed, leading to a coherent, unified theory for stress relaxation, creep, and strain and load controlled cyclic deformation. The study showed that over the stress, time, and temperature range where the rate of plastic flow can be approximated with activation over a single energy barrier, strain-controlled cyclic deformation is essentially a stress relaxation process, while creep is related to load-controlled cyclic deformation. The theory described well the deformation behavior of a near-eutectoid, zinc-aluminum alloy. The constitutive parameters determined from the analysis of stress relaxation, creep, and strain and load controlled cyclic loading experimental results were identical, leading to the conclusion that strain and load controlled cyclic deformations were different manifestations of the same basic process, depending on the control condition. Consequently, it was recommended that stress relaxation and creep can be employed to determine the constitutive parameters. By using the theory developed in this report, the cyclic deformation behavior can be predicted.
A Cleavage Precracking Technique for Sheet Steel Fracture Specimens
Authors: Clayton JQ , Rogers CB
Published: February 2009

A technique is described for the preparation of sheet steel fracture specimens containing a cleavage precrack instead of the usual fatigue precrack. Since the cleavage precrack can provide a high level of stress concentration and is free from cyclic-loading damage, such specimens are useful in the investigation of various fracture processes and mechanisms. The production technique involves low-temperature biaxial loading of a specimen blank to produce a cleavage crack extension, then separation of the specimen from the blank by electrical-discharge-machining (EDM). The stresses used to control the cracking are analyzed and discussed.
Diametral Strain Response and Microstructural Yielding Mechanisms of a Bainitic Pressure Vessel Steel
Authors: Rahka KA , Solin JP , Kemppainen MJ
Published: February 2009

Unexpected trends of diametral strain range response have been recorded for annealed bainitic Cr-Mo-V-pressure vessel steel at room temperature and moderate strain amplitudes. Stress and diametral strain response were also recorded for three harder heat treatment variants, but they behaved as expected. The alloy is strengthened by a carbide dispersion and a dislocation network, both of variable density. The unexpected diametral strain response is suggested to be associated with yet unknown macroscopic effects of particular observed microscopic mechanisms of slip. These mechanisms of slip can be analyzed with a model for dispersion strengthening which expresses the connection between nominal dislocation activity and the plastic and elastic components of elongation. The necessity for a differentiation between effective obstacles to slip consisting of stable carbides or cyclically unstable dislocation networks is arrived at. Observation of slip mechanisms by scanning electron microscopy is presented.
Sampling Variance: Bias and Reproducibility
Authors: Savage KI
Published: February 2009

Product quality necessitates the collection of a representative sample for analysis. The representativeness of a sample is measured by its accuracy or variance. Sampling variance is discussed in two parts, bias and reproducibility. Bias is an error that consistently results in either high or low analysis. Test methods for bias are described in detail. Reproducibility is a measure of expected fluctuation around the true result. Reproducibility can be reduced by additional increments, analysis, or both.
An Evaluation Method for Comparing Domestic and Foreign Materials Specifications
Authors: Early JG , Hime HL
Published: February 2009

Consistent decisions on the degree of equivalence between metal specifications of different national origins cannot be made only on the basis of chemical composition and direct comparison of mechanical property numbers. There are numerous additional factors, which, if present, can influence the determination of equivalency because of their effect on property requirements. In order to remove the uncertainty in this decision-making process, these additional factors must be evaluated in each comparison. A generalized approach has been developed in which evaluation criteria have been identified and discussed in terms of their role in the determining of equivalence. These criteria are presented as part of a guideline for conducting material specification comparisons.
A Standard-Reference Water-Suspended Sediment Sample for Total Recoverable Metals
Authors: Fishman MJ , Malo BA , Boyle DK
Published: February 2009

The U.S. Geological Survey has been preparing and maintaining a library of standard-reference water samples for dissolved inorganic constituents for 19 years. Recently, the reference-sample program was expanded to include a water-suspended sediment mixture for the determination of total recoverable metals. An interlaboratory round-robin study was conducted. Digestion procedures used by the U.S. Geological Survey and the U.S. Environmental Protection Agency were used to solubilize the metals before their measurement. The data indicate the both digestion procedures for total recoverable metals are essentially equivalent. Precision data are comparable to those data obtained in standard-reference water samples for dissolved metals.
Simple Measuring System for Electrical Energy Consumed by Auxiliaries for Advanced Batteries
Authors: Futamata M , Takahashi S
Published: February 2009

We have constructed a new measuring system of electrical energy for widely varying load current between 0.5 and 100 A using a controller for the current transformers (CT), a personal computer, and wattmeters. This system possesses special characteristics as a controller circuit of the CT. When the load current changes greatly, the most appropriate first terminal of the CT is instantaneously selected by the controller to provide an accurate measurement.

Firstly, the response of the system to varying power factors is discussed. Electrical energy was measured to an accuracy of ±0.45% for constant current loads with power factors between 1.0 and 0.4 and to an accuracy of ±0.68% for on-off current loads at every 5 min with power factors of 1.0 and 0.9. Secondly, the effect of distorted waveforms is discussed with regard to the accuracy of the system. It was verified that the system was scarcely affected by firing angles of the load current between 45 and 135°. In conclusion, the measuring system is applicable to the auxiliaries of the 10 kW class advanced batteries and also to other general loads possessing various power factors and distorted waveforms.
Dynamic Properties of Asphalt Concrete
Authors: Sousa J , Monismith CL
Published: February 2009

This paper describes equipment developed to determine the dynamic properties of paving materials in axial and torsional loading. Dynamic properties were determined by the excitation of hollow cylindrical specimens using two independent sinusoidal loads with frequencies up to 30 Hz.

An IBM PC/AT equipped with a Metrabyte DASH16 Data Acquisition Board was used to directly control two MTS Hydraulic Servorams. Menu-driven software was developed, taking advantage of DMA channels, so that data acquisition, waveform generation, and closed-loop control could simultaneously take place at rates above 5000 samples/s/channel. To convert raw data into graphs and parameters representative of dynamic material properties, a post-processing menu-driven program was also developed.

Dynamic properties for a dense-graded asphalt concrete are presented for a range in temperatures from 11 to 40°C and for a range in frequencies from 0.5 to 20 Hz. Test results include: dynamic moduli in axial loading defined by |E*|, dynamic shear moduli defined by |G*|, internal damping determined in both axial and shear loading, and dynamic Poisson's ratios. Also included are results illustrating the effects of specimen density on these properties.

Comparisons are included of stiffness moduli determined in a repeated pulse load test (resilient moduli) with those determined from the dynamic load equipment. The data also indicate that some care must be taken when comparing stiffness values determined by this type of loading with those determined from sinusoidal loading, particularly at higher temperatures. Differences in the stiffness moduli may result from the influence of the time between load applications (rest periods) on the value of the recoverable strain used to compute the stiffness (resilient modulus) in the repeated load test.
Measurement of the Spherical Tip of Rockwell Indenters
Authors: Barbato G , Desogus S
Published: February 2009

Recent international comparisons of primary standards of Rockwell C hardness showed that the indenter shape is largely responsible for differences in measurement results. Measurements, especially of spherical-tip shape, made by means of high-magnification (500 ×) profile projectors proved to be affected by an uncertainty that also depended on the operator. In connection with such problems, a measurement system using a rotating table centered by means of an air bearing was developed together with a method for result analysis so as to allow the evaluations required by ASTM and ISO standards to be made quickly.
Prediction of Specimen Strain from Extensometer Deflection Measurements in a Direct Stress Fatigue Test Specimen under Static Tensile Loading
Authors: Arora PR , Raghavan MR
Published: February 2009

The displacement between the ridges situated outside the filleted test section of an axially loaded unnotched specimen is computed from the axial load and shape of the specimen and compared with extensometer deflection data obtained from experiments. The effect of prestrain on the extensometer deflection versus specimen strain curve has been studied experimentally and analytically. An analytical study shows that an increase in the slope of the stress-strain curve in the inelastic region increases the slope of the corresponding computed extensometer deflection versus specimen strain curve. A mathematical model has been developed which uses a modified length ¯ℓef in place of the actual length of the uniform diameter test section of the specimen. This model predicts the extensometer deflection within 5% of the corresponding experimental value. This method has been successfully used by the authors to evolve an iterative procedure for predicting the cyclic specimen strain in axial fatigue tests on unnotched specimens.
Sensory Attenuation Induced by Modern Athletic Footwear
Authors: Robbins SE , Hanna A , Jones LA
Published: February 2009

Disorders that impair sensory perception can cause serious injury. It has been proposed that many running-related injuries may result from wearing athletic footwear which induces changes in the perception of loads encountered during running. To test this hypothesis a psychophysical investigation was performed in which subjects were required to give numerical estimates of the perceived magnitude of a load experienced on the plantar surface. The loads were applied to the flexed knee, and the foot was supported on one of three different weight-bearing surfaces.

The results indicated that there was a linear relation between the size of applied load and the perceived magnitude of this load on all three surfaces tested. Subjects consistently underestimated the magnitude of the loads applied, with the greatest underestimation occurring when the foot was either on a rigid plastic surface or wearing athletic footwear. The exponents of power functions fitted to these data were all close to one which is similar to the values obtained in studies of the perception of skin indentation on the palmar surface.

The results from this study support the hypothesis that athletic footwear can attenuate the perceived magnitude of loads experienced on the plantar surface. This change in the perception of load may be a factor in running-related injuries for which the term pseudo-neuropathic is proposed, since there are no pre-existing neurological deficits.

This experiment alerts one to the need for product safety standards, particularly for athletic footwear, so that the public can be protected from the dangers that may be inherent in their design, since these devices are promoted for use in high-impact environments.
Sensitivity of Fatigue Crack Growth Prediction (Using Wheeler Retardation) to Data Representation
Authors: Finney JM
Published: February 2009

Using the Wheeler model for predicting fatigue crack growth as a case study, the likely errors in prediction from selecting literature calibration values are examined. From four methods of representing the same da/dN - δK data, errors in crack life prediction up to a factor of about three were obtained.

Because calibration values are stress scale dependent, the influence of interpolations and extrapolations on predicted crack growth life is also examined. Large extrapolations may lead to errors in predicted life, also approaching a factor of three.
Recent Scientific Developments That Affect the Assessment of Risk Posed by Trichloroethylene and Perchloroethylene
Authors: Jones RE , Byrd DM
Published: February 2009

Trichloroethylene (TRI) and perchloroethylene (PER) are chlorinated hydrocarbons with similar chemical and toxicological properties. Cancer bioassay results with TRI and PER have shown increased incidence of liver tumors in B6C3F1 mice. Though the exact mechanism of tumor induction caused by TRI or PER is unknown, metabolic activation is strongly implicated. The major metabolite, trichloroacetic acid (TCA), induces peroxisomal proliferation (PP) in livers of rodents. Evidence suggests that PP in the liver is linked to the development of hepatic carcinomas. Whether PP is causative or just a by-product of liver cancer is unknown, but results establish that human cells do not react to TCA as rodent cells do. The current information on pharmacokinetics and mechanism-of-action for TRI and PER do not support a concern for carcinogenicity of exposed persons, based on findings of cancer in rodents. Moreover, the findings do not suggest a need for quantitative risk assessment.
Apparent Stiffness of a Butt Joint with a Thick Adhesive Layer and Elastic-Plastic Adhesives
Authors: Groth HL , Brottare I
Published: February 2009

The apparent stiffness of a thick adhesive layer in a butt joint is studied for adhesive materials with elastic-plastic material behavior. The finite element method was used for the determination of the joint stiffness as a function of the nominal strain. It was found that the stiffness obtained for the linear elastic case agreed with linear elastic solutions from the literature. Due to plasticity starting at the intersection of the adhesive and the adherend, the apparent stiffness of the adhesive layer decreases. The apparent stiffness reduction was not noticed below a nominal strain level of 0.5%.
Designing Bearing Fatigue Life Tests for Improving the Use of Testing Resources
Authors: Miller B , Hester D
Published: February 2009

A computer simulation study was conducted to investigate modifications of a current test plan for evaluating rolling contact fatigue life of experimental materials, so as to improve the use of testing resources and to produce more reliable data. The simulations revealed that a slight modification of the test plan, using available test rigs, could result in greater precision with fewer tests and a shorter average test duration.
Influence of Heat Treatment on Structure and Oxidation Behavior of Zr-2.5Nb
Authors: Ramanathan LV , Costa I , Monteiro WA
Published: February 2009

This paper presents the influence of different heat treatments on the microstructure and isothermal oxidation behavior of Zr-2.5Nb in oxygen. The quenched structure consisted of martensitic α′. Upon tempering the quenched alloy at 500°C for up to 100 h, βNb precipitated in the matrix, at twin and α′ needle boundaries. At higher tempering temperatures and after longer periods, Nb-rich βZr also precipitated. Specimens slowly cooled from the β-phase showed the least resistance to oxidation. The oxidation behavior also varied with the tempering time and temperature. The increased oxidation rate of specimens tempered at 500°C for 1000 h or at 600°C, as compared to those tempered at 500°C for shorter times, has been attributed to formation of Nb containing oxides on the coalesced Nb-rich precipitates and to cracking.
Cetane Number of Small Samples by Engine Throttling: Reliability Comparison with Standard Cooperative Fuels Research Method
Authors: Johnston RRM , van der Touw JW
Published: February 2009

The manifold pressure below which a diesel engine starts to misfire is related to the cetane number of the fuel. The method of engine throttling to misfire has been used to determine cetane quality of much smaller quantities of diesel fuel than can be used with the standard ASTM D 613 method. A comparison of reliability has been made between the two methods using identical test samples. The fact that published repeatability limits for ASTM D 613-84 are much smaller than the reproducibility limits suggests that there can be considerable bias at some laboratories using the standard method.

A method of calibration and computation is presented that provides reliable estimates of the accuracy of misfire pressure results without reference to other laboratories. Confidence intervals determined for the misfire pressure method are consistent with the observed difference in the results determined on the one set of test materials by the two methods. This suggests that, in the procedure for engine throttling to misfire proposed here, the interlaboratory component of error could be small.
Mechanical Evaluation and Performance Improvement of the Rotating Jaw Conibear 120 Trap
Authors: Cook SR , Proulx G
Published: February 2009

The momentum and clamping force values of a standard Conibear 120 rotating jaw animal trap and various modifications were determined using accelerometers and a load cell. These values were then compared against each other and against previous biological studies to determine which have the potential to quickly kill select species of animals.

It was found that by increasing the strength of the springs, and by adding clamping bars to the traps, it was possible to significantly increase both the momentum and clamping force of the standard Conibear 120 trap.

The Conibear 120 does not meet the requisites of the Canadian General Standards Board. More work should be done on traps, such as the C120 Mark IV, which do meet these requirements.
A Note on Dynamic Displacement Measurements Using Hall Effect Sensors
Authors: Giovanola JH , Kobayashi T , Klopp RW , Gaines T , Arwood R
Published: February 2009

We describe a transducer suitable for dynamic displacement measurements. The transducer uses a commercially available Hall effect sensor and a permanent magnet. Displacements are obtained by measuring the variation in magnetic field strength along the permanent magnet with the Hall effect sensor. To illustrate the capabilities of the transducer, we discuss three application examples. The first example demonstrates the good performance of the transducer under impact loading conditions and for velocities of up to 10 m/s. The other two examples illustrate the usefulness of the transducer for dynamic fracture experiments.
Low-Cycle Fatigue Analysis of Notched Members
Authors: Zhang D , Sandor BI
Published: February 2009

Low-cycle fatigue crack initiation and propagation lives of notched members are investigated. By relating Nci(ΔJ/ψρ)β = Cn to the Coffin-Manson equation and correlating to test results, β and Cn are found to be functions of several parameters: cyclic stress-strain constants, geometry of notch (depth and curvature), and stress ratio. (ΔJ/σ′y) is chosen as a parameter for crack propagation in notched members. Fatigue crack initiation and propagation tests were conducted on notched plate specimens of different notch radii and stress ratios. Crack initiation life, crack propagation life, and total fatigue life are compared with the calculations. There are good correlations between the test results and the calculations.
Chevron-Notched Specimens for Fracture Toughness Measurements Independent of R-Curve Effects
Authors: Barker LM
Published: February 2009

A relatively new plane-strain fracture toughness test method based on chevron-notched test specimens has created a keen interest in comparing toughness measurements by the new method against measurements by the conventional method (ASTM E 399). Tests of various aluminum alloys by the two methods have shown a divergence in test results at the higher toughness levels. The rising R-curve effect in tough aluminums has been cited as one of the factors contributing to the observed discrepancy. This paper shows why the chevron-notched test results are independent of rising R-curve effects, whereas ASTM E 399 tests often are not. The E 399 test dependence on the rising R-curve constitutes a specimen size effect, and this dependence is partly responsible for the divergence between chevron-notched and E 399 tests of tougher aluminums. The chevron-notched method produces the toughness values which would be obtained from E 399 measurements if sufficiently large E 399 specimens could be tested.
Effect of Strain Rate and Temperature on the Mechanical Anisotropy of Recrystallized Zircaloy TREX (Tube Reduced Extrusion)
Authors: Hussien SA , Murty KL
Published: February 2009

Tube Reduced Extrusion (TREX) is an intermediate product in the production of Zircaloy canning tubes for nuclear reactors. This paper studies the mechanical anisotropy, which has a direct relation to the formability of recrystallized Zircaloy-2 TREX. The yield stresses, as well as the anisotropy parameters (R and P) in the modified Hills equation, are evaluated using impression testing as a function of test temperatures and strain rates. The impression test offers a rather direct way for evaluating R and P through the uniaxial yield stresses along the three orthogonal directions. The anisotropy of the yield stress is evident at low test temperatures and decreases at high temperatures. The anisotropy parameter R is insensitive to test temperature (room temperature to 623 K) and strain rate (10−2 to 10−3s−1) and has a value close to unity. The P parameter decreases with increasing test temperature, approaching unity at 623 K.

There is a general trend for the anisotropy parameters to approach unity (the isotropic case) with increasing test temperature. This may be due to the activation of secondary slip systems. The linear relationship between compression and impression stresses, established at different test temperatures, is insensitive to the test temperatures within our range; it is in good agreement with the literature.