bluuebunny/crossref_metadata_2025_split huggingface dataset:
Marine Atmosphere Stress Corrosion Tests on Precracked Specimens from High-Strength Aluminum Alloys: Effect of Corrosion-Product Wedging
Authors: Dorward RC , Hasse KR , Helfrich WJ 
Published: February 2009

Abstract
Stress corrosion tests on precracked double-cantilever beam specimens from 2000- and 7000-series aluminum alloys have been in progress for up to seven years at a marine-atmosphere exposure site near Daytona Beach, Fla. One of the most significant results of these tests concerns the effects of specimen self-loading (because of exfoliation and corrosion-product wedging) on the relative crack growth resistance of different alloys. Self-loading is apparently affected by copper content but is not limited to copper-bearing alloys. Copper-free alloy 7039-T64, for example, showed self-loading effects after 3 to 4 years' exposure. Naturally aged 2XXX alloys and peak-aged, copper-containing 7XXX alloys were most sensitive to self-loading, usually showing the effects within six months. However, cracks in 7075-T73, a stress corrosion resistant alloy, also continued to propagate at rates that were not insignificant after several years' exposure, whereas alloy 2024-T851 appeared more resistant to corrosion-product wedging than 7075-T73.
Design and Performance of a Deadweight Standard Rockwell Hardness Testing Machine
Authors: Barbato G , Desogus S , Levi R 
Published: February 2009

Abstract
The design principles and main features of a deadweight standard hardness testing machine developed at the Instituto di Metrologia “G. Colonnetti” are described. Vickers and Brinell tests with deadweights ranging from 10 to 187.5 kg may be performed on the machine, which is built mainly for Rockwell A, B, and C scales.
Procedures for the Reduction and Testing of Bias
Authors: Visman J 
Published: February 2009

Abstract
The detection of bias depends on the precision of the sampling procedure that is employed to measure it. The significance of detected bias is therefore a relative matter; nonperformance of the bias test gives a one-sided answer only as smaller bias may exist. In fact, all measurements can be said generally to produce answers that are to some degree affected by systematic error. In this paper three different aspects are treated as starting points for formulating a standard method for bias: (1) the conditions under which bias occurs in the sampling of broken coal and factors that contribute to its control, (2) the means whereby bias can be reduced, and (3) the discussion of two procedures for the testing of bias. Attention is drawn to the terminology and the definitions that are related to the reduction and testing of bias, with special reference to the need for finding a common terminology in which the basic principles of probability are anchored down for public use regardless of the field of endeavor to which it is to be applied.
Acute Fish Toxicity and Absorption Tests of an Experimental Detergent Builder, Trisodium Carboxymethyloxysuccinate
Authors: Newsome CS , How MJ 
Published: February 2009

Abstract
Trisodium carboxymethyloxysuccinate (NaCMOS) is a new sequestering agent being evaluated as a builder in detergents. It contains neither phosphorus nor nitrogen and is readily and completely biodegraded in aerobic and anaerobic environments. The concentration of NaCMOS lethal to 50% of a batch of fish over 96 h (TLm96) in static tests is 2.9 g/litre and 2.3 g/litre for goldfish (Carassius auratus) and rainbow trout (Salmo gairdneri), respectively, in hard water (300 mg hardness/litre as calcium carbonate). These concentrations are 2300 to 160 000 times greater than the predicted concentrations that could occur in the aquatic environment from the use of NaCMOS as a detergent builder. The highly polar character of NaCMOS indicates that it would not be bioconcentrated; this is consistent with the results of absorption tests using 14C-labeled NaCMOS and goldfish. The results support the environmental acceptability of NaCMOS.
Fracture Modes and Acoustic Emission of Composite Materials
Authors: Rotem A , Altus E 
Published: February 2009

Abstract
Unidirectional fibrous composite material laminae are the construction material of a laminate. Four failure modes can occur in this material, and the identification of these modes is as important as the identification of onset of fracture. Acoustic emission (AE) pulses, generated by the change in the stress field resulting from cracking in a material, have a unique pattern of amplitude distribution that depends only on the mode of fracture and the type of material. By using a tapered double-cantilever beam as grips for the unidirectional lamina, a crack with a constant stress intensity factor was induced, thus eliminating the factor of the stress level. Placing the lamina in different directions relative to the grips imposed a different failure mode. By plotting the log of the relative number of AE pulses above some level versus the log of the relative level, a single constant coefficient can be measured for each material and mode of fracture. The AE energy is proportional to the energy released by the cracking; this proportionality depends on the medium where the AE waves have to travel, and not on the cracking mode.
Sampling and Analysis of Atmospheric Sulfur Dioxide with the Lead Dioxide Plate (Huey Plate)
Authors: Levadie B 
Published: February 2009

Abstract
The performance characteristics of the lead dioxide (Huey) plate for sampling sulfur dioxide are evaluated, and a method for determining sulfur dioxide as precipitated barium sulfate by weighing on an electrobalance is described. The data produced by exposing Huey plates over a two-year period are presented. A direct relationship between the concentration of sulfur dioxide in the ambient atmosphere as determined by continuous automatic monitoring and the mass loading of lead sulfate on the Huey plate has been confirmed. The correlation coefficient for the relationship was 0.90.
A Tower Extensometer
Authors: Findley WN , Lepper JK 
Published: February 2009

Abstract
A self-contained extensometer is described for rapid and highly accurate tension testing of several samples of rigid plastics over the entire range from zero load through fracture. The instrument has high sensitivity and linearity; negligible friction, backlash, and dead zone; a construction that permits installation after the specimen is located in the machine and that permits leaving the instrument on during fracture; and a design that averages the strain of the specimen. The instrument may also be used on metals whose hardness is significantly less than that of the gage points.
A Simple and Sensitive Method of Monitoring Crack and Load in Compact Fracture Mechanics Specimens Using Strain Gages
Authors: Deans WF , Richards CE 
Published: February 2009

AbstractThe calibrated strain on the back face (the face opposite that from which the slot is machined) of compact tension (CT) and T-type wedge-opening-loading (WOL) specimens provides a method for measuring crack length when the load is known or for measuring load when the crack length is known. The method is simple, reliable, sensitive, and inexpensive. A good correlation was achieved between strain measurements on a CT specimen and values computed from a two-dimensional finite element analysis. The method has good potential for developing into a more sensitive crack length measurement technique than has previously been achieved.Calibration tables and graphs are reproduced that describe the relationship between crack length, back-face strain, and load for CT and T-type WOL specimens of any size and thickness and for any linear elastic material.The method has several advantages over the closely related crack opening displacement (COD) technique for some test situations and these are described. In particular, the back-face strain increases linearly with crack length for constant stress intensity conditions except for very deep cracks in CT specimens. The overall characteristics render the technique ideal for incorporation into computerized/automated crack growth testing.For constant back-face strain, the stress intensity was shown to decrease with increase in crack length for both CT and T-type WOL specimens. This decrease is more pronounced than for corresponding constant COD testing and this provides a good technique for obtaining threshold fatigue or stress corrosion conditions.
The Influence of Bulk-Solution-Chemistry Conditions on Marine Corrosion Fatigue Crack Growth Rate
Authors: Bogar FD , Crooker TW 
Published: February 2009

Abstract
An exploratory study has been conducted to determine the influence of bulk-solution-chemistry conditions on corrosion fatigue crack growth rate in high strength alloys. Various solutions commonly employed in studies relating to marine corrosion were evaluated for their relative severity in crack growth rate tests. Related aspects involving aeration and applied cathodic potential were included. The results indicate that bulk-solution-chemistry conditions can influence measured values of corrosion fatigue crack growth rate by as much as a factor of three; however, the relative severity of various solutions can vary, depending on alloy composition.
Use of the Double Torsion Method to Study Crack Propagation in an Adhesive Layer
Authors: French RH , Raj R 
Published: February 2009

AbstractThe double torsion technique offers a simple method of studying crack propagation in adhesive layers. The method has been applied successfully to obtain crack-velocity versus crack-extension-force curves for fracture in bonds constructed from an epoxy and a nylon-impregnated adhesive. The thickness of the adhesive layer is found to have a significant effect on the fracture behavior.
Cohesive Bond Strength Prediction for Adhesive Joints
Authors: Flynn PL 
Published: February 2009

Abstract
An analytical study was carried out to derive the acoustic spectral response of an attenuating bond line. A similar effort was done to relate the time-base response of an attenuating bond line to the material properties of the adhesive. In this study, resonance separation, ultrasonic amplitude ratio, and resonance depth were related to the acoustic impedance, attenuation, and sound velocity of the adhesive layer.
Experimental verification of the derived correlations was provided by systematically varying the properties of Chemlok 304, a two-part paste adhesive, by mixing the adhesive in a range of proportions. Single overlap shear specimens were made with these adhesive mixtures and the adhesive properties were measured in situ with high frequency broadband ultrasonics. The ultrasonic data were reduced to yield the sound velocity, density, and attenuation coefficients of the adhesive mixtures. The specimens were tensile-tested to determine joint strength and stiffness. The strength and stiffness of the bonded joints correlated well with the ultrasonic amplitude ratio, sound velocity, attenuation coefficient, and resonance depth.
Laboratory Testing of Asphalt Concrete for Porous Pavements
Authors: Woelfl GA , Wei IW , Faulstich CN , Litwack HS 
Published: February 2009

Abstract
Laboratory testing was conducted to determine the effects of aggregate gradation and asphalt content on the stability and permeability of open-graded asphalt concrete. Test results indicate that permeability increases and stability decreases as the aggregate gradation becomes more open-graded, that is, includes less of the smaller sized particles. Also, permeability decreases as asphalt content increases whereas maximum stability occurs at an optimum asphalt content. Open-graded asphalt concrete was installed in the field for a porous pavement parking lot. The pavement has been serviceable for over two years, including exposure to winter conditions.
RCurve and Fracture Toughness of Thin Sheet Materials
Authors: Schwalbe K-H , Setz W 
Published: February 2009

AbstractCrack growth resistance R curve tests were done on center-cracked panels of three aluminum alloys. Two methods for the measurement of crack length were compared: the compliance method and the potential method. The latter gives more consistent results. It was found that the stress intensity serves as a correlation parameter for crack growth up to a limiting value of the net section stress that is equal to 0.9 times the yield strength. The fracture stress can be accurately predicted by the R curve concept.
Some Aspects of Fatigue Crack Closure in Two Contrasting Titanium Alloys
Authors: Halliday MD , Beevers CJ 
Published: February 2009

Abstract
Fatigue crack growth at intermediate rates was measured in compact tension specimens of the microstructurally contrasting alloys Ti-6Al-4V (Imperial Metal Industries, Ltd. [IMI] titanium 318) and Ti-6Al-5Zr-0.5Mo-0.25Si (IMI titanium 685). Sinusoidal loading was used with a ratio of minimum load to maximum load R of 0.1. The incidence of crack closure was examined during fatigue with both direct current potential drop and crack-opening-displacement (COD) methods; COD was found to be more reliable for closure measurement than potential drop. In contract to the fine-grained IMI 318, the coarse-structured IMI 685 showed substantial load transfer across the crack faces during fatigue and this was attributed to mismatch of the fracture faces. It was shown that the large differences in crack growth rate between the two alloys could be substantially accounted for by an effective stress intensity factor range concept. Marked reductions in growth rate produced by variable amplitude loading of the IMI 318 could not be explained in terms of crack closure.
The Effects of Stress Dwells and Varying Mean Strain on Crack Growth During Thermal Mechanical Fatigue
Authors: Gemma AE , Ashland FX , Masci RM 
Published: February 2009

Abstract
Two types of test were used to evaluate the effects of creep and thermomechanical fatigue (TMF) on the crack growth rates of two nickel-base superalloys: directionally solidified MAR-M200 + hafnium and conventionally cast B-1900 + hafnium. In the test type designated simulated creep/TMF, the mean strain was incremented by a fixed amount at the maximum cycle temperature of each 20th TMF cycle. For the test type designated as creep/TMF, a constant stress was imposed at the maximum temperature for a fixed time period of each 20th TMF cycle. The crack growth rates for both test types were generally higher than the average rates of the baseline data from pure TMF tests. The fracture surfaces of the simulated creep/TMF specimens showed a considerable amount of plane stress behavior, that is, changes in crack planes and growth along steep angular planes. On the other hand, the fracture surfaces of the creep/TMF specimens were more typical of crack growth under plane strain conditions. A strong correlation was found for both alloys between baseline primary creep rates and cumulative creep rates of the interaction test specimens.
Fatigue Crack Growth Rate Data Acquisition System for Linear and Nonlinear Fracture Mechanics Applications
Authors: Ruschau JJ 
Published: February 2009

Abstract
A computer-based, automated data acquisition system was developed for determining fatigue crack growth rate data for both linear and nonlinear fracture mechanics testing. The system hardware used was a Hewlett Packard (HP) 9825A desktop computer equipped with an HP 6940B multiprogrammer.
For linear elastic fracture mechanics (LEFM) testing, the crack growth rate da/dN is presented as a function of the stress intensity factor range ΔK. Compliance relationships are used to monitor crack length which is then used to calculate the stress intensity range.
For nonlinear fracture mechanics (NLFM) testing, the crack growth rate is related to the rate of potential energy change, or ΔJ. Compliance techniques are also used to monitor crack extension.
The results of both analysis methods obtained with the acquisition system for aluminum alloys 2124-T851 and 7075-T73 (Unified Numbering System [UNS] A92124 and A97075) are in excellent agreement with results obtained using the more conventional visual and analytical methods. The automated system is superior from a point of speed and consistency and possesses the accuracy required for valid crack growth testing. Furthermore, the system requires no personal supervision or special specimen preparation and thus would be available for obtaining fatigue crack growth results from test specimens that are subjected to adverse environments which preclude the use of visual measurements.
Determination of Crack Tip Energy Dissipation and Elastic-Plastic Fracture Toughness Parameter with Ductile Crack Extension
Authors: Shoji T 
Published: February 2009

Abstract
In order to evaluate the elastic-plastic fracture toughness parameter of nuclear pressure vessel steel, SA533B-C1 1 (Unified Numbering System [UNS] K12539), near and beyond general yielding, a newly developed technique for large plastic strain measurement, that is, the recrystallziation-etch technique, was applied to compact tension and three-point bend specimens with a crack length/specimen width of 0.6 that were tested to draw resistance curves for stable crack extension. Based on the results reported previously that the equivalent plastic strain distribution around the blunted crack tip could be measured by means of the recrystallization-etch technique, the plastic energy dissipation or work done within an intense strain region at the crack tip accompanying ductile crack extension was measured experimentally. Furthermore, the size and loading condition effects on this crack tip energy dissipation rate were examined in comparison with other candidate parameters for crack extension criteria in the presence of large scale plasticity. The size of the intense strain region could be regarded as equal to the process zone size where the fracture is taking place. Formation and extension characteristics of this zone were discussed from a view point of elastic-plastic fracture toughness parameters including the relationships with existing fracture toughness parameters such as crack opening displacement and J integral.
An Evaluation of a Load-Line Extensometer for Elastic-Plastic Fracture Toughness Testing
Authors: Williams JA , Carlson KW 
Published: February 2009

AbstractA load-line extensometer using linear variable differential transformer (LVDT) displacement transducers was developed and evaluated for use in multispecimen and single specimen J value versus crack growth (J-R) curve testing. The LVDT extensometer accuracy and repeatability was compared with that of clip gage extensometers commonly used in fracture toughness evaluatons. Data on load versus displacement and J value versus crack growth for ASTM A533, Grade B, Class 1 (Unified Numbering System [UNS] K12539) steel obtained by using both extensometers were also compared.
Residual Stress Profile in Machined Parts
Authors: Israeli A , Papiar R 
Published: February 2009

Abstract
The processes of machining precision parts have to be planned to result in low residual stresses, and a fast and reliable method is required to determine such stresses. A system was developed to meet this need. This system is based on continuous etching of a cylindrical specimen. Changes in specimen length are monitored as a function of etching time. The residual stress is then calculated with the Bauer and Heyn equation. Residual stress profiles caused by single point turning of 4340 steel (Unified Numbering System [UNS] G 43400) and maraging 300 steel specimens were evaluated by this procedure. This profile provides stress distribution in depth below the machined surface at various turning feeds, and it is used to define a residual tensile force. It is shown that an increase of feed increases the depth of the residual stressed layer and also increases the residual tensile forces. The ratio of residual tensile force to tool force as a function of the turning feed has a minimum.
Magnetic Properties of Iron and Low Carbon Steel for Soft Magnet Applications
Authors: Stokes JL 
Published: February 2009

Abstract
An investigation was conducted to assess the relative merits of five soft magnet materials proposed as alternatives to ARMCO Electromagnet Iron (EMI), which is no longer available. Four irons and an SAE J403 (1005) (Unified Numbering System [UNS] G10050) steel were considered. When annealed in 94% nitrogen-6% hydrogen at 843°C (1550°F) for 4 h and aged at 100°C (212°F) for 400 h, two of the irons were found to be equivalent to EMI with regard to both coercive force and magnetic stability. A third iron exhibited similar magnetic properties after annealing but required a higher annealing temperature to reduce the coercive force to an acceptable value. The fourth iron and the 1005 steel met the coercive force requirement after annealing at 843°C (1550°F) in 94% nitrogen-6% hydrogen, but suffered significant increases in coercive force during aging at 100°C (212°F).
Erosion Behavior of Polystyrene
Authors: Thai CM , Tsuda K , Hojo H 
Published: February 2009

Abstract
Erosion tests of polystyrene were made by impingement of glass beads at various attack angles and impact velocities. Two erosion damage peaks near the angles of 20 and 50°, which have never been observed on other materials, were found. In the erosion process near the peak of 50°, a characteristic ring-like damage pattern on the surface was recognized. To explain the experimental results, a new erosion mechanism based on the initiation and propagation of transverse cracks beneath the surface at the tip of longitudinal cracks was introduced. And by this mechanism, the erosion rate could be given by R = ρhS*/Mo where h, S*, and Mo are the factors describing the characteristics of the ring-like damage pattern and ρ is the density of material. The theoretical values agreed quite well with the experimental ones.
Isochronous Relaxation Curves for Type 304 Stainless Steel After Monotonic and Cyclic Strain
Authors: Swindeman RW 
Published: February 2009

Abstract
Relaxation tests to 100 h were performed on Type 304 stainless steel in the temperature range 480 to 650°C and were used to develop isochronous relaxation curves. Behavior after monotonic and cyclic strain was compared. Relaxation differed only slightly as a consequence of the type of previous strain, provided that plastic flow preceded the relaxation period. We observed that the short-time relaxation behavior did not manifest strong heat-to-heat variation.
Acoustic Emission Monitoring of Weldments
Authors: Hopwood T , Havens JH 
Published: February 2009

Abstract
Weld tests were performed on low-carbon and high-strength, low-alloy steel weldments. The weldments were monitored with an acoustic emission detector during both the “in-process” and the “in-cooling” phases of the welding operation. Artificial defects were induced in several of the welds to promote cracking. Some high-strength weldments were designed to produce welds subject to high restraint. Nondestructive and destructive evaluation of the completed weldments revealed that high acoustic emission activity during in-cooling could be correlated with embedded defects and cold-cracking. Copious emission activity was also detected from unflawed weldments. Acoustic emissions were detected in high-strength steel weldments for periods up to 265 h. However, there was no clear relation between the duration of acoustic emission activity and cracking. On a per-electrode-deposited basis, high-stressed welds produced more emissions than low-stressed welds.