bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Measurement Precision and Data Processing Procedures on Variability in Fatigue Crack Growth Rate Data
Authors: Wei RP , Wei W , Miller GA 
Published: February 2009

Abstract
Variability in experimental data on fatigue crack growth kinetics reflects contributions not only from material property variations and environmental and other uncontrolled variables but also from measurement precision used in determining the primary data (that is, crack length versus elapsed cycles) and the subsequent data processing procedures in determining rates from the primary data. To assess the contributions of measurement precision and data processing procedures to variability, computer simulation of primary fatigue crack growth data was made for a number of measurement intervals and precisions. These simulated data were analyzed by several data processing procedures.
Variability in the derived growth rate data was found to depend strongly on the magnitude of the measurement interval relative to the measurement precision. This variability was reduced by data processing procedures, such as incremental polynominal methods, that fitted a smooth curve through portions of the primary data. Such procedures, however, can introduce statistically significant bias into the derived data on crack growth kinetics; this bias may or may not cause large errors in predicted fatigue life. Because variability associated with crack length measurement interval and precision and with data processing procedures can be quite large and is incorporated in an unknown way into much of the published data on fatigue crack growth rate, caution should be exercised in drawing statistical inferences regarding material differences from such data. Suitable procedures that would allow assessment of material differences from experimental crack growth data need to be developed.
Statistical Analysis of Notch Toughness Data
Authors: Koons GF 
Published: February 2009

Abstract
In the usual method for analyzing notch toughness values only a few specific notch impact measurements are selected for experimental study. In obtaining these results, many of the experimental data are not used quantitatively. Some experimenters have used a four-parameter function, called the hyperbolic tangent, to summarize impact test data that can be assumed to follow an S-shaped pattern. The proposed method of analysis uses the parameters of this function rather than the actual impact test results to analyze changes in the notch toughness of metals. This method allows one to study the effect of the experimental variables on the shape of the entire curve rather than on one specific point on the curve. In addition, the curve parameters can be used to predict temperatures associated with any notch toughness measurement. An estimate of the variability of the prediction can also be calculated.
Application of Fatigue Life Prediction Techniques to Materials Substitution
Authors: Sherman AM 
Published: February 2009

Abstract
The applicability of a computer-based fatigue life predictive technique to materials substitution has been tested by performing a fatigue design analysis on an automobile frame crossmember. The original steel component and an alternate aluminum design were instrumented and installed in a test car, and the vehicle was driven over a standard rough road durability route to record road load histories. The recorded histories were used with a previously developed computer-based predictive technique to obtain component life predictions. Laboratory-program loading of samples of the two materials using the recorded histories confirmed the accuracy of the life predictions. Finally, by taking into account both material property differences and structural design parameters, it was shown that a service history obtained from one component can be used to predict the fatigue life of the component made of alternative materials. This procedure can be of significant value in the consideration of materials substitutions even in situations where design changes accompany the substitution.
Acoustic Emission Monitoring of High-Temperature Cyclic Oxidation Damage in a Titanium-Aluminum-Vanadium Alloy
Authors: Baram JC , Itzhak D , Rosen M 
Published: February 2009

Abstract
The feasibility of using acoustic emission techniques to monitor high-temperature thermal cycling oxidation damage in Ti-6Al-4V was studied between 600 and 900°C. Acoustic emission distribution analysis was applied to discriminate between different mechanical processes that lead to spalling of the oxide layers. It has been proven that acoustic emission follows very closely the exact material oxidation damage mechanism. Plastic deformation and partial stress relief in the oxide alloy system give rise to increasing emission of low peak amplitude pulses. Cracking and fracture of the oxide's scale, followed by spalling, produce a high rate of acoustic emission, with an increased fraction of high peak amplitude pulses. Nondestructive monitoring of oxidation damage in Ti-6Al-4V by acoustic emission was shown to be able to predict the onset of catastrophic spalling of the oxide's scale.
Three-Point Bending at Large Deflections of Beams with Different Moduli of Elasticity in Tension and Compression
Authors: Paolinelis SG , Paipetis SA , Theocaris PS 
Published: February 2009

Abstract
An analytical investigation of three-point bending at large deflections was carried out with materials exhibiting different moduli of elasticity in tension and in compression. It was found that the solutions developed by the authors elsewhere for equal moduli materials were still valid, provided that load and beam depths were replaced by equivalent values derived by multiplying the actual values by factors that were functions of the moduli ratio only. The moduli ratio, even for small deviations from unity, was found to influence the behavior of the system considerably. Interaction with friction at the supports could render experimental results unreliable, and hence complete knowledge of the reaction forces during the bending test, both by magnitude and direction, appears to be necessary. Experimental evidence appears to support the present theoretical predictions.
A Critical Evaluation of Pulse Collectors for Utilities
Authors: Jensen RM 
Published: February 2009

Abstract
Several types of fabric filters are used to remove fly ash from the products of combustion of large coal-fired power plants. This article compares two types of cylindrical bags: inside collectors and outside, or pulse, collectors. A synopsis of the evolution of the outside collector precedes a discussion of the merits and shortcomings of both types of collectors. Various claims made by adherents of outside collectors are then discussed. Finally, the costs of replacing bags in the two types of collectors are compared.
A Biaxial Fatigue Machine for Elevated Temperature Testing
Authors: Brown MW , Miller KJ 
Published: February 2009

Abstract
A biaxial fatigue rig has been developed to study failure under low cycle fatigue conditions. The tubular specimen can be subjected to axial load, torque, and internal pressure enabling a wide range of stress/strain states to be obtained under strain-controlled conditions. A four zone furnace has been developed for elevated temperature tests, while allowing strains to be measured from the gauge length.
Stress Intensity Factors for Single-Edge-Crack Solid and Hollow Round Bars Loaded in Tension
Authors: Bush AJ 
Published: February 2009

AbstractDimensionless stress intensity factors were determined for single-edge-crack solid and hollow round bars loaded in tension. These factors were calculated from experimental compliance (inverse slope of load-displacement curve) measurements made over a range of dimensionless crack depths (lengths) from 0.05 to 0.65. The tests were made with 76-mm (3-in.) diameter solid and hollow round bars notched on one side and loaded in axial tension. The hollow bar had an inner to outer diameter ratio of 0.33. A comparison was made with data in the literature for rectangular bars; for a crack depth to diameter ratio of 0.0001 the dimensionless stress intensity factor for a solid round bar is 0.55 compared with 2.0 for a rectangular bar.
Stress-Strain Characteristics of Reinforcing Steel Bars Under Cyclic Loading
Authors: Desayi P , Iyengar KTSR , Reddy TS 
Published: February 2009

Abstract
This paper presents test results for 22 high strength deformed bars and nine mild steel bars subjected to monotonic repeated and reversed axial loading to determine the stress-strain behavior. Equations have been proposed for the stress-strain curves and have been compared with test results. Satisfactory agreement was obtained.
Truncated Sequential Sampling Plan for Use in Determining the Grade of Wool
Authors: Reals HC , Muse D 
Published: February 2009

Abstract
The objective of average fiber diameter measurement is to determine the grade of a lot of wool with a reasonable degree of certainty. A sequential sampling plan for each of the 16 U.S. Department of Agriculture (USDA) grades of grease wool was developed in an effort to reduce the minimum number of fiber measurements specified for grade determination. The sequential sampling plan was applied to 61 samples representing 14 USDA grades of grease wool. Forty-four (72%) of the samples were determined to be in the proper grade on a sequential basis before the currently prescribed minimum number of fibers were measured.
Reliability of Results of Analyses After Multiple Testing of Petroleum Products
Authors: Zanker A 
Published: February 2009

Abstract
A formula for the estimation of the reliability of analyses after multiple testing of petroleum products was developed and published as ASTM Standard Practice for the Utilization of Test Data to Determine Conformance with Specifications (D 3244-77). A nomograph included in this paper allows the solution of the complicated formula easily, quickly, and with reasonable accuracy.
Fitting Curves to Toughness Data
Authors: Oldfield W 
Published: February 2009

Abstract
Curve-fitting (regression) procedures for toughness data have been examined. Approaches using the normal probability function and the tanh function to model the transition between brittle and ductile behavior have been briefly reviewed. The objectives of fitting such curves have been summarized in the context of the study of nuclear pressure vessel steels as (1) convenient summarization of test data to permit comparison of materials and testing methods; (2) development of statistical statements concerning the data, and (3) the study of changes in material behavior, particularly radiation damage. These objectives impose differing demands on the curves, which result in several versions of each approach. The computational and mathematical procedures that can be used with the tanh function have been described in detail, with examples of the different curves that can be fitted to the data. Six different algorithms to be used for situations involving different constraints have been summarized. Weighted regression has been reviewed briefly, with emphasis on the use of models to describe the changes in variance between the different modes of material behavior.
Reproducibility of the Surface Area of Some Powders as Measured by the Monosorb® Surface-Area Analyzer Using the Brunauer-Emmett-Teller Equation
Authors: Ace HL , Parsons DS 
Published: February 2009

Abstract
The precision of the measurement of the specific surface area of powders was studied for 15 different materials. Measurements were obtained in such a way that both instrument and sampling contributions to the total errors could be estimated. The overall coefficient of variation was 6.5%. The instrument reproducibility was 2.7%. The total reproducibility of free-flowing powders was 4.2%, but for non-free-flowing powders, which are hard to sample, the total reproducibility was 8.5%.
A Statistical Analysis of X-ray Stress Measurement by the Gaussian Curve-Fitting Method
Authors: Kurita M 
Published: February 2009

Abstract
Simplified equations for calculating peak position and its standard deviation caused by counting statistics, which is a fundamental source of scatter in X-ray stress measurement, are derived for the Gaussian curve-fitting method. These equations when used with an inexpensive microcomputer will facilitate a precise and rapid residual stress determination. The time required for calculating the peak position and its standard deviation with such a microcomputer is only 0.9 s.
The residual stress in a hardened structural steel, Type JIS S45C, was measured. The standard deviation in the stress as measured by the Gaussian curve method was smaller than that by the parabola method, which until now has been the most widely used technique.
The variation in peak position in the Gaussian curve method with the various selections of data points used in the calculation is also smaller than that in the parabola method. Since the correction for background has little influence on the results, it can be omitted to reduce the measurement time.
A Constant Force System for Delayed Fracture Experiments
Authors: Wycherley GW , Henshall SG 
Published: February 2009

Abstract
A loading system has been developed to apply constant tensile forces to test pieces for delayed fracture investigations. The basic element of the system is a high compliance ring in which the test piece is loaded across the ring diameter after precompressing the ring in a universal testing machine. Details of ring compliance and forces achievable for rings cut from readily available pipes are given and simple techniques for monitoring the applied force are described. A reduction in cross-sectional area of 30 to 40%, consequent upon effective crack growth during testing, would result in about a 1% decrease in force for a ratio of compliances of ring to test piece of 5.5 to 1.
Simultaneous Determination of Shear and Young's Moduli in Composites
Authors: Fischer S , Roman I , Harel H , Marom G , Wagner HD 
Published: February 2009

Abstract
An experimental method is described to calculate both shear and Young's moduli of composite materials by three-point bending. The proposed procedure includes appropriate corrections for certain extraneous effects. The importance of the two basic ratios, E/G, which is an indicator of the degree of anisotropy of the material, and L/d, the span-to-depth ratio, is underlined.
Design of a Dynamic Gear Test Rig
Authors: Crawford RJ , Brown D 
Published: February 2009

Abstract
A test rig for plastic spur gears has been designed and built, based on the principle of an eddy current dynamometer. This offers considerable advantages over existing gear test rigs in that the torque level is infinitely variable and it can be adjusted if necessary during testing. A special noncontacting tooth breakage detector was also developed to stop the tests immediately if failure had occurred.
An extension to the basic test procedure is also described whereby real life loading situations can be easily simulated with a minicomputer coupled to the dynamometer.
Hydrogen Embrittlement of Zinc Coatings
Authors: Horvick EW 
Published: February 2009

Abstract
A brief review is given of hydrogen embrittlement of zinc-coated steel. Most of the steel that is hot dip galvanized is low carbon grade and, as such, little if any hydrogen embrittlement is incurred. Much of the steel that is electroplated is higher carbon grade and, thus, possibly subject to this problem. Methods of overcoming this are suggested. Most of the study on the subject has been with still plating; very little has been done with barrel plating.
An investigation on the effect of alkaline zinc electroplating on embrittlement of hardened parts under barrel plating conditions is reviewed. A pertinent consideration was the verification of previous observations that the use of zincate solutions reduce hydrogen embrittlement compared to those formulated with cyanide. Although many techniques have been used to measure the hydrogen embrittlement level, a simplified bend test with inherent advantages was used here.
A description of cathode surface preparation and embrittlement testing is discussed. Results are analyzed and interpretation of this is developed.
Multiaxial Fatigue: A Survey of the State of the Art
Authors: Garud YS 
Published: February 2009

AbstractThis paper surveys the current state of knowledge concerning multiaxial fatigue. Developments are presented in chronological order and are discussed so as to supplement existing reviews in this field. Emphasis is placed primarily on the criteria or methods of evaluation of fatigue strength under general multiaxial loading at room temperature. The survey indicates that the early development of the criteria was based on extensions of static yield theories to fatigue under combined stresses. These are stress-based criteria limited primarily to high-cycle fatigue. Most of the later criteria are strain-based. These criteria fall into two broad groups: the equivalent stress or strain type and the critical plane type. Most of these criteria commonly lack considerations of the cyclic stress-strain response. Their application to nonproportional loading suffers from difficulties in implementation or from inconsistencies with results of experiments. Recent approaches fall in the category of continuous damage evaluation methods. At present, these appear to be abstract or difficult to implement. All the above criteria are critically examined and compared. With this background, a new plastic work approach, proposed by the author, is discussed briefly.
Estimation of Cavitation Erosion with Incubation Periods and Material Properties
Authors: Veerabhadra Rao P , Martin CS , Syamala Rao BC , Lakshmana Rao NS 
Published: February 2009

Abstract
A detailed study of the normalized correlations between the incubation period tc and the properties of various materials tested in a rotating disk device indicates that, at very high intensities, the strength properties influence the duration of tc. The analysis of extensive data from other laboratories for cavitation and liquid impingement erosion also indicates that, while both energy and strength properties influence the duration of tc, the latter ones predominate for a majority of cases. A fatigue-type failure occurs during tc. For estimating the time required to pierce a metallic specimen in a rotating device a relationship tp = 160 tc0.44 is proposed. A detailed study of normalized correlations between erosion resistance (inverse of erosion rate) and tc values of different materials tested in the rotating disk shows that correlations are good. Analysis of data from eight other investigators clearly points out the validity and the usefulness of this type of prediction.
Quality Control of Tests Conducted on Bituminous Mixtures in Quebec
Authors: Zaikoff P , Bouchard A , Langlois R 
Published: February 2009

Abstract
The quality assurance system of the Quebec Ministry of Transport uses laboratory test results to evaluate the quality of bituminous concretes. The success of the system depends to a large extent on the reliability of these results. To evaluate on a day-to-day basis the reliability of the results, the Ministry developed a method to control the quality of laboratory tests based on the precision and accuracy of the test method used (that is, interlaboratory control) and on the reliability of results obtained by each laboratory (that is, within-laboratory control). The application of such a method has permitted the Ministry to obtain and even increase the confidence that the quality assurance system will succeed. It has also allowed the Ministry to detect and correct certain weaknesses attributed either to the test methods or the laboratories.
Precision Strain Measurement at Elevated Temperatures Using a Capacitance Probe
Authors: Keusseyan RL , Li C-Y 
Published: February 2009

Abstract
A new type of capacitance displacement measuring system has been developed. The gage is directly attached to the specimen for measurements at elevated temperatures. This system has been successfully used in materials testing at temperatures up to 600°C with excellent repeatability and resolution in strain in the 10−6 range. Good temperature stability of the entire system is required to achieve the reported capabilities.
Characterization of the Crack Toughness Behavior of Structural Steels by the Tearing Modulus Parameter and Acoustic Emission
Authors: Khan MA , Shoji T , Takahashi H 
Published: February 2009

AbstractThe combination of elastic-plastic fracture mechanics and acoustic emission techniques is used for evaluating the fracture toughness behavior of structural steels. The results show that for certain situations the acoustic emission technique can be used to accurately estimate the J integral at a growing crack and therefore provide predictive information regarding failure in laboratory specimens of different geometries and sizes. The invariance of the normalized J resistance curve is demonstrated for the compact and bend configurations. A simple and realistic test method is proposed for the evaluation of a critical value of the J integral and the tearing modulus parameter in cases in which the scatter is of particular concern. Correlation between acoustic emission and the tearing modulus parameter is presented that permits an acoustic “rating” of the material. In addition, the significance of an extending ductile tear on the structural integrity in terms of tearing modulus and acoustic emission is discussed.
Acoustic Emission During Unloading of Elastically Stressed Magnesium Alloy
Authors: Lee SS , Williams JH 
Published: February 2009

Abstract
Acoustic emission (AE) has been recorded for a magnesium alloy that has been quasi-statically cycled elastically between zero load and tension. Delayed AE was observed during both loading and unloading, and the stress delay during unloading is further studied. An analytical expression is written for the AE unloading stress delay which is an elastic constitutive parameter. The potential use of these results for the acoustic emission monitoring of elastic stress states is discussed.
An Introduction to Some Precision and Accuracy of Measurement Problems
Authors: Grubbs FE 
Published: February 2009

Abstract
Errors of measurement and the imprecision and inaccuracy of instruments are defined with the aid of appropriate statistical analyses often required in such a treatment. Techniques are given for estimating and characterizing the parameters related to precision and accuracy of measurement. The concepts are highlighted with illustrative examples of the methodology, and useful precision and accuracy statements are advanced.
Effect of Weathering at Different Exposure Angles on the Tensile Impact Resistance of Thermoplastics
Authors: Yamasaki RS , Blaga A 
Published: February 2009

Abstract
The ability of a thermoplastic to serve as an exterior building component depends to a large extent on its impact strength and the retention of this property during service. A study was undertaken of the effect of the Canadian climate on the tensile impact strength (TIS) of eight clear and opaque commercial thermoplastic sheets exposed at different angles, and on the mechanism responsible for their loss of impact strength. The TIS of unexposed thermoplastics ranged from 98 kJ/m2 for poly(methyl methacrylate) (PMMA) to 1225 kJ/m2 for ultraviolet-stabilized polycarbonate, surface unprotected (PC). Following south/vertical (S/V) and horizontal (H) exposure the TIS of these thermoplastics was reduced from 20% S/V and 30% H for PMMA after five years to 65% S/V and 85% H for PC with a protective film after one year. For most of the thermoplastics tested, loss of TIS may be attributed to deterioration of ability to undergo plastic deformation, rendering the material more brittle.