bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of Variability in Resilient Modulus Test Results (ASTM D 4123)
Authors: Brown ER , Foo KY 
Published: February 2009

Abstract
Samples of asphalt mixture were evaluated in the laboratory under various conditions to evaluate the repeatability of the resilient modulus test and the effect of stress on the measured resilient modulus. Some samples were prepared in the laboratory, others were obtained from in-place pavements that had been subjected to traffic. The independent variables included stress, test temperature, and maximum aggregate size.
Tests were repeated a number of times, and the data were analyzed by Statistical Analysis System (SAS) to investigate their repeatability. This study quantified the repeatability of the ASTM D 4123 resilient modulus test as a function of stiffness. The repeatability of ASTM D 4123 is low. A significant increase in the number of samples or number of measurements is required to improve the repeatability. Tests conducted at different stresses showed the resilient modulus to be stress sensitive. This indicated that stress should be specified in the test procedure. A correction factor was established for stresses differing from the recommended stress (15% of tensile strength) for test temperatures of 25 and 40°C.
Deformation of Aluminum Alloy under Cyclic Creep Loadings
Authors: Gong ZL , Hsu TR 
Published: February 2009

Abstract
Cyclic creep tests were conducted on an aluminum alloy at 160 and 200°C. Measured results indicated that mechanical load cycling with long dwell periods can produce significant creep acceleration. Such creep acceleration not only resulted in the increasing of minimum strain rate at subsequent loading cycles, but also reduced the creep rupture life of the material. Microstructure examinations by TEM and SEM were carried out to study microstructural damages under monotonic and cyclic loadings. Results indicated that remobilization of dislocation and damage enhancement during stress cycling were chiefly responsible for creep acceleration.
A Thick Adherend, Instrumented Double-Cantilever-Beam Specimen for Measuring Debonding of Adhesive Joints
Authors: Crosley PB , Ripling EJ 
Published: February 2009

Abstract
An inexpensive test method for evaluating the debond resistance of adhesive joints is described. A double-cantilever-beam specimen is used, and a strain gage is mounted on the unbonded portion of one adherend. When a fixed displacement is applied to the end of the specimen, the strain gage output along with the specimen compliance and the amount of fixed displacement at the end of the specimen are used to calculate the crack length, a, and the sustainable crack driving force, G, at the time the gage is read.
Charpy Impact Tests Near Absolute Zero
Authors: Tobler RL , Reed RP , Hwang IS , Morra MM , Ballinger RG , Nakajima H , Shimamoto S 
Published: February 2009

Abstract
We review Charpy impact testing at extreme cryogenic temperatures, especially at liquid helium temperature (4 K), considering methods of testing and calibration, thermal behavior during the various stages of testing, and correlations between Charpy absorbed energy and quantitative toughness parameters. Because of the very low specific heats of metals near absolute zero, any surface condensation of gases, convective or conductive heat transfer, or plastic deformation during a test will cause the specimen temperature to rise rapidly. Consequently, valid impact tests of alloys at 4 K can not be performed according to the procedure outlined in ASTM Methods E 23-88. During Charpy tests, the temperature of austenitic steel specimens, initially at or near 4 K, may in fact rise outside the cryogenic regime. Fracture does not occur at the intended temperature, but at an uncontrolled temperature, since materials with different work hardening rates heat differently. In view of the temperature rise variability and scatter in measurements and property correlations, we conclude that it is not possible to accurately estimate the 4 K fracture toughness of ductile steels, or rank them properly, using Charpy tests.
Improved Wide Range Expressions for Displacements and Inverse Displacements for Standard Fracture Toughness Specimens
Authors: Kapp JA 
Published: February 2009

AbstractWide range expressions (interpolating polynomials) for displacements for standard ASTM fracture testing specimens have been developed. The strategy was to fit displacements as a function of crack length for all the specimens using a similar form of nondimensional displacement. Different forms appear in different ASTM standards for the same or similar specimens. The criterion used to establish the degree of polynomial fit and number of significant figures for the coefficients of the polynomial was for the polynomial to agree with the best available numerical displacement solutions to within 1% or better. Once the polynomials for displacement as a function of crack length were developed, inverted forms of the specific interpolating polynomials were obtained to determine relative crack length (a/W) as a function of displacement. Since the inverted polynomial will be used in tandem with the interpolating polynomial, the inverted polynomial was fit to the interpolating polynomial and not the numerical solution for displacement. Three forms of nondimensional displacements were used to invert the interpolating polynomials. The criterion used to establish the degree of polynomial and the number of significant figures of the coefficients of the polynomial was for the predicted relative crack length to agree with the actual relative crack depth to within 0.0005W. A sensitivity analysis was performed to suggest which form of interpolating polynomial should be used for standards.
Computer-Aided Homogeneity Testing of Proposed Metal and Metal Alloy Reference Materials
Authors: Hurwitz JK 
Published: February 2009

Abstract
In an analytical laboratory, reference materials are used for several purposes, including the calibration of analytical instruments, periodic standardization of these instruments, and verification that the standardization is correct. Reference materials are also used to confirm that an analysis is performed with optimum precision and is not biased, and to determine the presence and effects of interferences. All of these applications require that proposed reference materials be evaluated for homogeneity. To this end, specimens are cut at regular intervals from bars selected for evaluation and identified accordingly. Across the entire cross section of each specimen, a flat surface is prepared as specified by the analytical method. The specimens are analyzed in random order by optical emission spectrometry, once at the center of the specimen and twice as close to the edge of the specimen as possible. If X-ray emission (fluorescent) spectrometry is used, two analyses are performed with a fresh specimen preparation before each analysis. Statistical analyses are performed on the values obtained for each element to determine whether there are significant differences in composition between center and edge or among specimens. This procedure has been used successfully for ten years to evaluate proposed reference materials prior to certification.
A Novel Specimen Geometry for Double Shear Creep Experiments
Authors: Kim H-K , Mohamed FA , Earthman JC 
Published: February 2009

Abstract
A new specimen geometry has been developed to reduce the stress concentrations at the ends of the gage section in double shear creep specimens. The purpose of the geometry is to reduce the tendency for crack formation at the gage section ends when testing creep brittle materials. A comparison of creep data indicates that the sharp corners at the ends of the gage sections of the conventional geometry has a negligible effect on the steady-state creep behavior. The results also suggest that, when a nonuniform gage section is used, the stresses redistribute during primary creep such that steady-state flow is driven by the mean shear stress over the entire gage section.
Design and Analysis of Jaw Crusher Gouging Abrasion Tests
Authors: Sare IR , Constantine AG 
Published: February 2009

Abstract
ASTM Standard Practice G 81-83 describes a laboratory procedure for determining the relative gouging abrasion resistance of materials in a jaw crusher. The authors have found a number of problems associated with the test procedure, particularly in respect of its inefficiency, the fact that it yields biased estimates of the wear parameter, and its lack of facility for assessing the significance of differences between test results. An alternative methodology for conducting the tests and for analyzing the data is proposed, and it is shown, by example, how substantially more information can be obtained from tests results than has hitherto been demonstrated.
Specimen Size Requirements for Fracture Toughness Testing in the Transition Region
Authors: Anderson TL , Dodds RH 
Published: February 2009

AbstractThe article utilizes plane strain elastic-plastic finite element analysis and a local criterion for cleavage fracture to establish specimen size requirements for the ductile-brittle transition region. Critical J and CTOD values, relative to the small-scale yielding value, were predicted as a function of specimen size, strain hardening exponent, and a/W. These analyses predict an increase in the apparent toughness with decreasing specimen size due to a loss in crack tip constraint; this effect is particularly pronounced in shallow notched specimens and low hardening materials. For deeply notched bend and compact specimens, the following size requirement must be met for critical J values for cleavage to be size independent: b,B,a&gt;200JcσY where b is ligament length, B is thickness, a is crack length, and σγ is flow stress. This criterion is eight times more severe than the size requirements in ASTM E 813-87, but it is less stringent than the requirements of ASTM E 399-83. In order for a CTOD value to be nearly size independent, it must be less than 1/300 times the relevant specimen dimensions.The constraint loss in shallow notched specimens is usually far too rapid to obtain J-controlled cleavage fracture, but the analyses presented in this article provide a means for correcting fracture toughness data for constraint loss. Predictions of the effect of a/W on toughness in the transition region agree favorably with experimental data.Future work will consider the effects of specimen thickness and ductile tearing on transition region toughness.
Plastic η and γ Factors for Compact Tension Specimen inJ-Integral Estimation
Authors: Hu JM , Albrecht P 
Published: February 2009

AbstractThe empirical expressions for the plastic η and γ factors adopted by ASTM in the standard test methods for Jlc and J-R curve testing (E 813 and E 1152) were determined from the results of experimental work. This note proposes instead expressions of ηp and γp that are derived from a limit load solution. The results show that over the range of crack lengths recommended for testing in the ASTM standard test methods, a/W = 0.5 to 0.75, the proposed ηp value is 5.11 to 1.42% greater than the ASTM value, and the proposed γp value is 12.93 to 5.82% greater.
Pulse Current Automatic Electro-Optical Characterization of the Laser Diode
Authors: Oyedokun ZO 
Published: February 2009

Abstract
An automated pulse current testing of the laser diode is presented. Built around an accurate and fast rise time pulse generator and a minicomputer, it has been used to test several laser diodes to extract characteristics such as threshold current and thermal resistance. The computer-controlled pulse generator offers multivariable control of output pulse. Control and data acquisition algorithms were developed in a low level language, MACRO11, to enhance speed and resource utilization, and in FORTRAN, which facilitated the man/machine interface or manware. Continuous wave and pulse test results are compared to illustrate the heating effects.
Prediction of the Strength of Ceramic Tubular Components: Part II—Experimental Verification
Authors: Shelleman DL , Jadaan OM , Conway JC , Mecholsky JJ 
Published: February 2009

Abstract
The strength distribution of reaction-bonded silicon carbide tubes that failed by internal pressurization was predicted from strength distributions obtained from simple laboratory test specimens at room temperature. The strength distributions of flexure bars, C-rings tested in tension, C-rings tested in compression, diametrally compressed O-rings, and internally pressurized short tubes were compared with the strength distribution of internally pressurized long tubes. The methodology involved application of Weibull statistics using elasticity theory to define the stress distributions in the simple specimens. The flexural specimens did not yield acceptable results, since they were ground before testing, thereby altering their flaw population in comparison with the processing-induced flaw populations of the tubular specimens. However, the short tube internal pressure test, the C-ring tested in tension, and the diametrally compressed O-ring test configurations yielded accurate strength predictions of full-scale tubular components, since these specimens more accurately represent the strength-limiting flaw population in the long tubes.
Accuracy of a Volume Fraction Measurement Using Areal Image Analysis
Authors: Shi D , Winslow D 
Published: February 2009

Abstract
The method of interval estimation is used to determine the accuracy of a volume fraction measurement obtained from an areal image analysis of a series of images. The accuracy is found to depend upon the average number of objects found in each section and the number of sections that are analyzed. The method can be applied to completed measurements on a set of two-dimensional sections to estimate the error in the result. Or, the method can be used before making any measurements to select the number of sections and the size of each section for a desired accuracy.
Nonintrusive Test for Argon Gas Content in Windows: Feasibility Study
Authors: Latta BM , Bogan L , Wagner GS 
Published: February 2009

Abstract
The objective was to find a nonintrusive technique for determining the gas content of an insulated glass window unit. During this study, first measurements of the electric breakdown field for air-argon mixtures were obtained. The breakdown field does not depend strongly on whether the electrodes are plain window glass or glass with low emissivity coatings, nor does it depend on the glass electrode spacing. Our reported strong variation of the breakdown field with admixtures of air to the argon gas suggests that this approach could provide an inexpensive nonintrusive gas analysis for insulated glass window units with an ultimate precision of 0.1% on the argon content.
Shear Strength of a Ductile Material from Torsion of Solid Cylinders
Authors: Lyon RE 
Published: February 2009

Abstract
The shear strengths of two ductile epoxies are obtained from solid cylinder torsion using a data reduction scheme. The results are in quantitative agreement with shear data from torsion of thin-walled tubes of the same materials, particularly with regard to the coincidence of the peak yield stress and strain. The described technique is useful for characterizing ductile material behavior in shear using a simple, solid cylinder specimen.
The Structural Ceramics Database: Data Acquisition Format for Monolithic Ceramics
Authors: Munro RG , Begley EF 
Published: February 2009

Abstract
The Structural Ceramics Database (SCD) is being developed to provide a user-friendly, computerized database of materials properties for advanced ceramics. The acquisition and the maintenance of adequate and comprehensive data are two of the critical concerns that must be addressed in establishing a state of the art system. This paper describes the basic SCD format used for data on monolithic ceramics. This format prescribes a comprehensive means for tabulating, annotating, and crediting data. The experience gained in developing this format for the SCD is discussed in the context of the issues confronting ASTM Committee E-49 on Computerization of Materials Property Data.
Theoretical Comparison of Error in KIc Values Determined by Different Testing Methods of Ceramics
Authors: Martins CS , Steen M , Rosa LG 
Published: February 2009

Abstract
Experimental errors in measuring the values of the different variables included in the formulae for KIc evaluation can affect the accuracy of fracture toughness results. In this work, the effect of error propagation, leading to the final error in the KIc value, is analyzed in terms of type of testing method and specimen geometry.
A review of eight different specimen geometries and procedures for fracture toughness testing of ceramics is given. The analysis was carried out through a FORTRAN 77 program specially developed for this purpose. The computer program takes into account the allowable errors that are associated with each type of recommended experimental procedure or common practice. Results obtained on hot-pressed silicon nitride (HP Si3N4) are presented as an example, but the conclusions can be extended to other engineering ceramics.
Procedure to Evaluate Openings in Children's Products for Head Entrapment Hazards
Authors: Deppa SW 
Published: February 2009

Abstract
Children have strangled when their heads became entrapped in structural openings of children's products. To analyze these accidents, we applied human factors principles of anthropometry, childhood development, perception, behavior, and biomechanics. Children under 5 years of age became entrapped either head first, feet first, or neck first. Four product characteristics contributed to accidents: product function, product weight/size, opening location, and opening configuration.
From this analysis, we developed a standard procedure for evaluating product openings. This procedure describes how to develop test fixtures to simulate the smallest and largest users at risk. This work can assist, and has assisted, product designers, manufacturers, and the U.S. Consumer Product Safety Commission in reducing head entrapment in product openings. For example, this procedure was used to develop provisions in ASTM voluntary standards for baby gates and enclosures, bunk beds, and playground equipment.
Laboratory Testing of River Gravel Used in Arrester Beds
Authors: Al-Qadi IL , Rivera-Ortiz LA 
Published: February 2009

Abstract
The objective of this study was to investigate the engineering properties of a river gravel. The engineering properties studied included shear strength, volume change, failure strain, and modulus of elasticity. The triaxial compressive strength of the river gravel was used in a developed model to obtain the stopping distance of a runaway truck in an arrester bed.
Static and dynamic triaxial compression tests were performed using a specially constructed triaxial cell on specimens 22.9 cm (9 in.) in diameter and 48.3 cm (19 in.) in height. Specially designed damping equipment was employed to perform the dynamic testing. The test specimens were subjected to different confining pressures.
The results of the study not only provide data on strength, relative volume change, failure strain, and modulus of elasticity but also on the relationship between these properties and influencing factors such as relative density, confining pressure, and loading rate. The material parameters of the river gravel were applied successfully in a mathematical model developed to predict the stopping distance of a run-away truck in an arrester bed.
Warm Precracking at 295 K and Its Effects on the 4-K Toughness of Austenitic Steels
Authors: Tobler RL , Shimada M 
Published: February 2009

Abstract
Experiments show that some austenitic steels at extreme cryogenic temperatures are toughened by warm prestress. We demonstrate this for Fe-17Cr-3Ni-13Mn-0.33N steel specimens that were warm precracked at 295 K and then fractured in liquid helium at 4 K where failure occurs by slip-plane cracking. On the other hand, Fe-13Cr-5Ni-22Mn-0.21N steel with higher toughness and a ductile fracture mechanism at 4 K was not affected by similar warm precracking. Austenitic and ferritic steel behaviors are compared, and precracking procedures for 4-K fracture tests are discussed.
Electrical Resistance Measurements on Type 304 Stainless Steel with Different Degrees of Sensitization
Authors: Kain V , Chouthai SS , Gadiyar HS 
Published: February 2009

Abstract
Most of the test methods commonly used to evaluate the susceptibility of austenitic stainless steels to intergranular attack are qualitative and destructive in nature. Practice A of ASTM Standard A 262 and the EPR tests are nondestructive but are less discriminating for higher degrees of sensitization. Because the sensitized material contains chromium-rich carbides at grain boundaries and chromium depletion zones at and adjacent to the grain boundaries compared with uniform structure in the solution annealed material, there is a need for a nondestructive test method using electrical resistance, eddy current, ultrasonic testing, or magnetic susceptibility. Testing methods based on eddy currents and ultrasonics are reported to be insensitive to the degree of sensitization. In this study an attempt is made to measure the electrical resistance for Type 304 stainless steel (SS) with various degrees of sensitization. The results indicated no correlation between the electrical resistance measurements and the degree of sensitization for Type 304 SS.
Energy Stored in a Specimen under Fatigue Limit Loading Conditions
Authors: Kaleta J , Blotny R , Harig H 
Published: February 2009

Abstract
This paper presents results of measuring the energy stored in a specimen made from Ck 35 carbon steel loaded with an alternating one-directional stress whose value is equal to the fatigue limit. The energy stored in the specimen was determined in an indirect way as the difference between the mechanical energy expended in the specimen and the energy released into the surroundings as heat. The proposed technique is a modified version of the dynamic hysteresis loop method. The energy released as heat was measured with an electric modelling method.
It was found that the energy stored during one cycle in a specimen loaded with a stress equal to the fatigue limit was larger than zero (i.e., with Nf→ ∝, the stored energy value theoretically also tends to infinity). To make the theory of the experiment compatible with the fundamental assumption stating that the amount of energy needed to cause fracture is constant irrespective of loading conditions, it is necessary to introduce a rheological function accounting for all reversible processes occurring in a material under cyclic loading.
Analysis of the Size Effect in Low-Load Hardness Testing of Metals
Authors: Atkinson M 
Published: February 2009

Abstract
Recent accounts of Vickers hardness tests in which the variation of hardness values with indentation size was suppressed by lubrication are re-examined to elucidate the nature of the size effect. It is shown that a simple constant error in either the measured indentation size or the force actually exerted would not explain the effect. A good description of the effect is obtained by reference to an indentation-size-dependent load error which is sensitive to both friction conditions and the plastic properties of the test material.