bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of Crack Depth on the Fracture Toughness of Reactor Pressure Vessel Steel
Authors: Theiss TJ , Bryson JW 
Published: March 2009

The Heavy Section Steel Technology Program (HSST) at Oak Ridge National Laboratory (ORNL) is investigating the influence of flaw depth on the fracture toughness of reactor pressure vessel (RPV) steel. Recently, it has been shown that, in notched beam testing, shallow cracks tend to exhibit an elevated toughness as a result of a loss of constraint at the crack tip. The loss of constraint takes place when interaction occurs between the elastic-plastic crack-tip stress field and the specimen surface nearest the crack tip. An increased shallow-crack fracture toughness is of interest to the nuclear industry because probabilistic fracture-mechanics evaluations show that shallow flaws play a dominant role in the probability of vessel failure during postulated pressurized-thermal-shock (PTS) events.
Tests have been performed on beam specimens loaded in three-point bending using unirradiated RPV material (A533 B). Testing has been conducted using specimens with a constant beam depth (W = 94 mm) and within the lower-transition region of the toughness curve for A533 B. Primarily two crack depths have been considered: a = 50 and 9 mm (a/W = 0.5 and 0.1). Three specimen thicknesses (B = 50, 100, and 150 mm) have been used to examine the influence of different out-of-plane constraint conditions on the test results. All tests resulted in cleavage failures. Test results indicate a significantly higher fracture toughness associated with the shallow flaw specimens compared to the fracture toughness determined using deep-crack (a/W = 0.5) specimens. The toughness increase is comparable with the toughness increase found at the University of Kansas using steels whose stress-strain properties bound those of A533 B. Test data also show little influence of thickness on the fracture toughness for the current test temperature (-60°C). The Irwin βc correction has been modified to account for shallow flaws and was used to estimate the shallow-flaw toughness based on the results from the deep-crack specimens.
Effects of Crack Depth and Mode of Loading on theJ-RCurve Behavior of a High-Strength Steel
Authors: Joyce JA , Hackett EM , Roe C 
Published: March 2009

This paper describes an experimental program which had the objective of developing a series of J-R curve data from laboratory specimens of varied constraint. Constraint was varied by testing specimens with different thicknesses, crack lengths, and mode of loading. All specimens were relatively small and were kept simple in geometry and loading to allow estimation of the applied J integral. Crack length-to-width ratios were varied dramatically from a/W = 0.10 to a/W = 0.65 and the mode of loading ranges from three-point bending of deeply cracked edge-notched bars to pure tensile loading of double edge-notched strips. All tests were conducted on a single material, a high-strength structural steel, at ambient temperature, which is well up on the ductile upper shelf for this alloy.Results of these tests have shown that different constraint conditions can dramatically affect the JIc and the J-R curve for the full range of crack lengths and loading modes studied here, and these effects can be studied on relatively inexpensive laboratory specimens. Observed trends correspond to generally expected ideas of “increased constraint” or “decreased constraint” conditions, but since no factor is available to satisfactorily quantify constraint, an ability to utilize a data set such as this to predict the behavior of a material for a particular structural application is still lacking.
Taguchi Experiment on Strength Correlation Between a Customer and Supplier of Porous Coatings
Authors: Peterson RR 
Published: March 2009

Problems in correlating porous coating pull-off strength test results through the use of test coupons led to the use of Taguchi methods to isolate the variables that contribute to test result differences between the customer and supplier of these coatings.
In the past, the supplier would test the coupons representative of the parts and ship the parts believing the pull-off strength requirements were met. The customer then tested additional coupons and usually found a lower strength (sometimes below specification) which resulted in rejection of the material. This, of course, led to problems. If both testing sources had correlated at a particular strength level, whether it be high or low, there would be no question as to the disposition of the material. Therefore, the major concern was that the numbers from both testing sources agree.
Since there are scores of variables that could affect the pull-off test, general categories were selected to determine major sources of variation that could be further analyzed at a later date if necessary. The four sources of variation (factors) that were selected included: (1) who performed the gluing operation on the coupons (the supplier or the customer); (2) at which facility the pull-off test was performed (the supplier's or the customer's); (3) what testing fixture configuration was used (two different types); and (4) at what speed was the tensile machine run (two different speeds).
Two analysis methods were used which concluded that the difference in fixturing was probably the most important source of varination While the other factors were significant, it was discovered that the highest pull-off strength values were obtained by having the customer glue the sample and the supplier run the test. This would mean that neither the customer nor the supplier had an overall better technique, further verifying the main source of vanation was in the fixturing.
Mechanical Evaluation of Soft Tissue and Ligament Implant Fixation Devices
Authors: Stewart NJ , Muneta T , Lewis J , Lindquist C , Arendt E 
Published: March 2009

The purpose of this study was to define a new mechanical measure of soft tissue fixation device performance and to use the method to assess the fixation performance of three fixation systems. The commonly used screw and spiked washer (SSW, Synthes) was tested as a method to fix both tendon and Ligament Augmentation Device (LAD, 3M Co.). Also tested was fixation of an LAD with a custom designed ligament implant fixation tab (LIFT). Specimens, goat tendons or LADs, were fixed under 44.5 N of tension to two flat segments of goat bone. Five specimens were tested for each group.
After specimen fixation, increasing loads were applied to the specimen. One bone block was cyclically moved an incrementally increasing distance away from the other, along the axis of the specimen. Between applied loads the bone blocks were returned to their original positions. Two measurements were made at each level of applied load. The first was the force remaining in the specimen with the bone segments in their original positions. The second was the elongation required to return the fixed specimen to its original tension. The second measure was termed slippage, and includes effects of viscoelastic and plastic deformation of the tendon/LAD at both fixation points and within the tendon/LAD. Cyclic loading was continued until failure.
The results are quantified in Table 1. This study demonstrates that soft tissue fixation devices may be characterized by loss of tension, and elongation required to regain original tension, as a function of applied loads. Such information may be useful to evaluate devices that are designed to reduce slippage.
Fatigue Response of Metal Matrix Composites
Authors: Schulte K , Trautmann K-H , Leucht R , Minoshima K 
Published: March 2009

Results are presented on the fatigue behavior of continuous fiber-reinforced aluminum and titanium alloys, both reinforced with SiC fibers. The pure aluminum matrix was reinforced with the “Tyranno” fiber of Ube, Japan, while the Ti6Al4V matrix was reinforced with the SCS-6 fiber of Textron. Also investigated was an Al-2.5Li alloy reinforced with α-Al2O3 FP fiber from DuPont.
The fatigue behavior of the MMC composites was observed to be superior when compared to the fatigue behavior of bulk matrix material. This was especially true for the case of tension-compression loading, where the overall superior compressive behavior of MMCs played a dominant role.
Failure in an MMC with unidirectional reinforcement normally initiates at or near imperfections, such as misaligned fibers, voids, foreign inclusions, or surface damage with subsequent fatigue crack propagation. An answer is given as to whether the variation of stiffness due to damage development can be used as a damage analogue. Finally, an explanation of the fracture behavior is given.
Fracture Testing and Performance of Beryllium Copper Alloy C17510
Authors: Murray HA , Zatz IJ , Ratka JO 
Published: March 2009

When a literature search and discussion with manufacturers revealed that there was virtually no existing data related to the fracture properties and behavior of copper beryllium alloy C17510, a series of test programs was undertaken to ascertain this information for several variations in material processing and chemistry. These variations in C17510 were primarily optimized for combinations of strength and conductivity. While originally intended for use as cyclically loaded high-field, high-strength conductors in fusion energy research, material testing of C17510 has indicated that it is an attractive and economical alternative for a host of other structural, mechanical, and electrical applications.
ASTM tests performed on three variations of C17510 alloys included both J-integral and plane strain fracture toughness testing (E 813, E 399) and fatigue crack growth rate tests (E 647), as well as verifying tensile, hardness, Charpy, and other well-defined mechanical properties. Fracture testing was performed at both room and liquid nitrogen temperatures, which bound the thermal environment anticipated for the fusion components being designed. Fatigue crack propagation stress ratios ranged from nominal zero to minus one at each temperature. In order to confirm the test results, duplicate and independent test programs were awarded to separate facilities with appropriate test experience, whenever possible.
The primary goal of the test program, to determine and bound the fracture toughness and Paris constants for C17510, was accomplished. In addition, a wealth of information was accumulated pertaining to crack growth characteristics, effects of directionality, and potential testing pitfalls. The paper discusses the test program and its findings in detail.
The Evaluation of Fatigue Damage in Short Fiber-Reinforced Styrene-Maleic Anhydride
Authors: Hoppel CPR , Pangborn RN 
Published: March 2009

The fatigue behavior of short glass fiber-reinforced styrene-maleic anhydride (S/MA) is investigated in this study. Six material configurations were manufactured into tensile bars by injection molding and tested in tension-tension (R = 0.1) fatigue to evaluate the ways the interface controls the change in the mechanical properties of the composite. These materials included unreinforced S/MA as a reference material and composites incorporating fiber reinforcement with different average diameters, two volume fractions, the presence or absence of an interfacial silane coupling agent, and fibers prepared with an acrylonitrile/butadiene latex coating. These materials have been tested under both “wet” (immersed in water at 25°C) and “dry” (50% relative humidity at 25°C) conditions. Three indicators were monitored during fatigue to evaluate the damage in the experimental materials: the degradation of the secant and fatigue moduli, the hysteresis energy per cycle, and the concurrent acoustic emissions produced during fatigue. This information is presented with S-N curves to show the relationship between these indicators and the fatigue lives of the materials.
The fatigue performance (life curves and cyclic stress-strain curves) was directly related to the fiber-matrix interface. Since water weakens the interface, especially in the composites without a silane coupling agent, composites tested in the aqueous environment exhibited shorter fatigue lives than the specimens tested in the dry environment. Interfacial coatings that included a silane couplant were found to reduce the effects of water on the fatigue lives of the composites. This damage in the composites was reflected in the decrease in the elastic modulus and the increases in the hysteresis energy and acoustic emissions. These evaluation techniques show that fatigue damage accumulates in a three-stage process in the material.
Characterization of Adhesively Bonded Joints by Acousto-Ultrasonic Techniques and Acoustic Emission
Authors: Nayeb-Hashemi H , Rossettos JN 
Published: March 2009

Reliable applications of adhesively bonded joints require an effective nondestructive evaluation technique for their bond strength prediction. To properly evaluate factors affecting bond strength, effects of defects such as voids and disbonds on stress distribution in the overlap region must be understood. At the same time, in order to use the acousto-ultrasonic technique to evaluate bond quality, the effect of these defects on the dynamic response of single lap joints must be clear.
The Stress distribution in a single lap joint with and without defects (void or disbond) is analyzed. A θ parameter that contains adherend and adhesive thickness and properties is introduced. It is shown for bonded joints with θ ≥ 10 that a symmetric void or disbond in the middle of overlap up to 70% of overlap length has a negligible effect on bond strength. In contrast, frequency response analyses by a finite element technique showed that dynamic response is affected significantly by the presence of voids or disbonds. These results have direct implication in the interpretation of acousto-ultrasonic results.
Through-transmission attenuation and a number of acousto-ultrasonic parameters for various specimens with and without defects are evaluated. It is found that, although void and disbond have similar effects on bond strength (stress distribution), they have completely different effects on wave propagation characteristics. For steel-adhesive-steel specimens with voids, attenuation changes are related to the bond strength. However, the attenuation changes for specimens with disbond are fairly constant over a disbond range. In order to incorporate the location of defects in acousto-ultrasonic parameters, a weighting function is introduced. Using an immersion system with focused transducers, a number of acousto-ultrasonic parameters are evaluated. It is found that, by incorporating weighting functions in these parameters, better sensitivities (acousto-ultrasonic parameters versus bond strength) are achieved.
Acoustic emission activities of steel-adhesive-steel specimens with θ = 3.4 are monitored. Two different formats of energy versus time have resulted, each corresponding to the perfect specimens or the specimens with void or disbond. The relative acoustic energy and number of events at failure are found to be a means of predicting bond strength.
Verification of Pavement Responce Models
Authors: Ullidtz P , Krarup J , Wahlman T 
Published: March 2009

When backcalculating layer moduli from Falling Weight Deflectometer (FWD) tests and when forward calculating critical stresses and strains, a number of assumptions have to be made. Some of the important assumptions normally are that 1) the system is in equilibrium, 2) the materials are continuous and remain continuous under deformation, and 3) the materials are elastic, isotropic and homogeneous.
None of these assumptions are valid for FWD testing of real pavement structures. A number of mathematical models exist for describing the pavement response, but they are all based on idealization of real pavement structures and materials. The only way of determining whether a given mathematical model is acceptable for pavement design or evaluation, is by comparing the response predicted by the model to that measured in real pavements.
Many attempts at doing this have been done over the years, but none of them have let to the conclusive verification of a specific mathematical model. This paper presents the results of measurements carried out on four instrumented test sections, one in the Danish Road Testing Machine and three on experimental sections in Sweden. On all sections the deflections were measured with a FWD, the layer moduli were backcalculated using different methods, and the stresses and strains in different materials, caused by FWD loading or by traffic loading, were calculated and compared to the stresses and strains measured at the same locations with pressure and strain gauges.
Stochastic Analysis of Errors in Remaining Life Due to Misestimation of Pavement Parameters in NDT
Authors: Vennalaganti KM , Ferregut C , Nazarian S 
Published: March 2009

The recent mechanistic-empirical approaches for predicting the remaining life of flexible pavements are mainly based upon the predicted strains at the interfaces of different layers. To determine these strains, nondestructive testing techniques are utilized. Unfortunately, uncertainties in determining the strains may result in significant errors in the predicted remaining life. A number of major factors that contribute to these inaccuracies include the imprecise knowledge of thickness and Poisson's ratio of each pavement layer and the errors in measuring the loads and the deflections using a NDT device.
A methodology which accounts for these uncertainties in the assumed pavement parameters and measured responses is suggested herein. With this methodology the influence of these parameters on the calculation of the remaining life of the pavement can be quantified. The methodology is based on Monte Carlo simulation techniques and has been used to analyze four pavement sections, representing a wide range of highways from secondary to interstate. The results of the probabilistic analysis show that the variability in pavement parameters increases the probability of failure of the pavement.
Accelerated Weathering of Geosynthetics
Authors: SUITS LD 
Published: March 2009

Over the past eight to ten years Committee D35 on Geosynthetics has been struggling with the question of accelerated weathering of geosynthetic products. This paper will attempt to describe the difficulties that have been encountered in developing an appropriate test standard for geosynthetic materials. The difficulties are both in the testing itself, and the use of the results of the testing.
The current test method for geotextiles was adopted in 1984. The method uses the xenon-arc type apparatus. Ever since 1984 the Committee has been performing inter-laboratory test programs aimed at preparing a precision statement for the method. Several factors have prevented this from happening. These include the difficulty in equipment calibration at the site of operation, which equipment manufacturers have indicated needs to be carefully controlled. One other factor which has made the process extremely difficult is the variation in the materials tested.
Development of Simulated Acid Rain Test Using CCT Method
Authors: Suga S , Suga S 
Published: March 2009

At present there are no established test methods for corrosion due to acid rain. The authors carried out experiments to find an adequate simulated acid rain corrosion test method.
Various types of cyclic corrosion tests (CCT) for automotive metallic materials have been widely utilized in Japanese automotive industries and a test method (JASO M 609) was standardized in 1991. This method is based on cyclic procedure in which one cycle comprises 2 hours of salt spray using neutral 5% sodium chloride solution, 4 hours of dry-off and 2 hours of damp heat.
The simulated acid rain test we developed is based on CCT method, except for the test solution which is prepared by adding nitric acid and sulfuric acid to neutral 5% sodium chloride solution. The experiments included tests on four standard bare metals (copper, zinc, aluminium and steel), and metallic and paint coatings on steel.
45 cycles in the Acid rain CCT device correspond to one year of outdoor exposure in the Tokyo area and on Okinawa in reproducing the deterioration of paint coatings as well as metallic coatings.
Comparison of TOX and GC/MS Data for RCRA Groundwater Monitoring Well Samples
Authors: Pruskin SL , Voo L , Mason RM , Lillian D 
Published: March 2009

The method for the analysis of total organic halogen (TOX) was developed as a means to trace the products of disinfection in drinking water. It was intended to measure, collectively, compounds such as trihalomethanes and halogenated ethanes. Briefly, the method involves passing a measured amount of sample through a column of activated carbon, followed by pyrolysis of the carbon and analysis of the gases produced for total halogen (as chloride) by microcoulometric titration. It has been shown to produce good recoveries for spiked deionized water and for other simple, fairly clean waters that are free of turbidity. This method is documented as Method 9020 in SW-846 (Test Methods for Evaluating Solid Waste).
RCRA regulations require the monitoring of TOX as an indicator of groundwater contamination at many hazardous waste management facilities (40 CFR 265.92). Method 9020 is recommended as an economical method for TOX analysis. Another way of measuring TOX is to analyze samples for volatile and semivolatile organics by GC/MS (SW-846 Methods 8240 and 8270) and calculating the sum of the halogen contents (as chloride) of all compounds that are found.
Samples from RCRA groundwater monitoring wells are generally more complex than the drinking water samples that were analyzed when Method 9020 was initially evaluated. In the Region II laboratory we have analyzed many groundwater samples by Method 9020 and by Methods 8240 and 8270. This report is a presentation of a preliminary comparison of the results obtained by these two techniques.
Review of Studies Concerning Effects of Well Casing Materials on Trace Measurements of Organic Compounds
Authors: Dowd RM 
Published: March 2009

This report analyzes the results of laboratory and field studies that allow a direct experimental comparison among commonly used monitoring well casing materials (stainless steel, Teflon, rigid PVC) in terms of their potential effects on measurements of trace organic compounds. Each of the studies analyzed attempts to determine experimentally how much -- if any -- sorption occurs, or what differences result among measured concentrations of a series of organic compounds.
In comparing the measured trace concentrations to determine whether the well casing materials cause significant differences in results, a ratio was formulated to reflect the relative sorption effects of each of the materials; sensibly constant ratios over a reasonable range of trace concentrations would indicate few, or relatively minor, differences between the various materials, while varying ratios would indicate larger differences. Conclusions are drawn about similarities and differences in sorption behavior; additional observations about sample variation, effects of well purging, and limited measurements of non-volatile compounds are noted.