bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fracture Mechanics Characterization of the Trino Reactor Vessel Material
Authors: Mager TR , Davidson J , Galliani M 
Published: March 2009

During preirradiation testing it became known that the Trino reactor vessel material exhibited a Charpy-V upper-shelf impact energy level of approximately 36 ft∙lb in a direction transverse to the plate rolling direction. Current U.S. practice is to require 75 ft∙lb impact energy for materials in the beltline region of the reactor vessel. It was proposed that fracture toughness properties be obtained on Trino reactor vessel Plate W6306-1 in terms of both fracture mechanics parameters and conventional Charpy-V impact energy. Concurrent with preirradiation testing of Plate W6306-1 an accelerated irradiation program was initiated in a test reactor.
To generate the fracture toughness data, compact tension specimens were tested both statically (KIc) and dynamically (Kid). The encapsulated specimens were irradiated at 550°F (288°C to a fluence of 3 × 1019 neutrons (n)/cm2 (E &gt; 1 MeV).
The fracture toughness data obtained from the preirradiation testing indicated that Plate W6306-1 meets the intent of the ASME Appendix G, KIR curve. Postirradiation fracture toughness data (static and dynamic) from the accelerated radiation program indicated that the fracture toughness for transverse specimens was approximately 100 ksi (in.)½. The upper-shelf impact energy of the Trino vessel Plate W6306-1 decreased a maximum of 7 ft∙lb during the accelerated irradiation.
Based on the fracture toughness properties obtained during the evaluation, it was concluded that Plate W6306-1 exhibited adequate toughness to provide for continued safe operation of the Trino Vercellese Nuclear Power Plant.
Computer-Aided Structural Analysis and Design of Concrete Pipe
Authors: Wenzel TH , Parmelee RA 
Published: March 2009

This paper describes the development of a finite-element computer program to simulate the structural behavior of a buried concrete pipe. The influence of the soil-structure interaction phenomenon is approximated by using appropriate material properties for the bedding and backfill, and by employing empirical hinging mechanisms which enable simulation of the progressive cracking behavior in the model of the concrete pipe. A second approximation, in which the pipe is represented as a linear frame, is introduced for the calculation of internal stress resultants. Various iteration techniques are employed to ensure deformation compatibility between the two pipe models. The results from full-scale experimentation are then used to validate the analytical models.
This model of the soil-pipe system was combined with appropriate serviceability and ultimate strength design criteria for reinforced concrete pipe to produce a comprehensive computer program for the design of buried concrete pipe. The resulting program, entitled NUPIPE, accounts for nonlinear soil-structure interaction, and permits the engineer to obtain the structural design of a given size pipe having a specified fill height and installed in any manner (that is, arbitrary bedding or backfill procedures or both).
The applicability of the new design method is demonstrated by designing various installations. The required steel areas for these installations are compared with those obtained by use of the current design method, and the differences are discussed.
Use of Laboratory Failure Simulation Exemplars to Study Intergranular Fracture Modes in 9Ni-4Co-0.20C Steel
Authors: Young JD , Kumar A 
Published: March 2009

During structural spectrum load testing of the aft-fuselage structure of the B-1 aircraft, a 124-mm-long crack was detected in the 9Ni-4Co-0.20C steel primary structure. Review of the fracture location revealed that the crack path was adjunct to a production weld used in the fabrication of the 727-kg (1600-1b) forged and welded horizontal-vertical stabilizer support assembly. Upon removal and examination of the fracture on a scanning electron microscope, two distinct fracture modes were observed: (a) at the origin, a 0.5 to 1-mm intergranular fracture mode was observed, followed by (b) 123 mm of transgranular high-stress low-cycle fatigue crack propagation.
Fatigue crack growth rate analysis on the scanning electron microscope showed that the fatigue crack started propagation at the onset of testing, strongly suggesting a pre-existing crack which was corroborated by the observation of an intergranular fracture mode at the origin, which exhibited no evidence of cyclic growth.
A laboratory failure exemplar study program was conducted to establish standards for intergranular fracture mechanisms possible in 9Ni-4Co-0.20C steel, fabricated using the same environmental conditions as present during manufacturing. The salient features of the fractographs of known failure mechanisms were used to establish the cause of service failure intergranular cracking to be hydrogen embrittlement.
Role of Interface Chemistry in Failure of Materials
Authors: Joshi A 
Published: March 2009

Properties of many materials are influenced strongly by small compositional changes that occur at interfaces such as phase and grain boundaries. Knowledge of the elements involved and whether they are segregated or present in a second phase provides a better understanding of the failure mechanism. In many instances of grain boundary failures, the chemistry provides the most comprehensive and useful information. Examples of such studies discussed here include temper embrittlement and other forms of impurity-induced low temperature embrittlement, weld-metal embrittlement, grain boundary corrosion, and intergranular stress corrosion cracking. Failures at phase boundaries and other more macroscopic interfaces such as encountered in fiber/metal matrix composites, interparticle interfaces in powder metallurgy materials and bonded (thermal compression, solder, or diffusion bonded) interfaces also can be understood by close examination of chemistry of these interfaces.
In many of these examples, the zone of segregation at boundaries is very small, only a few angstroms, the same as the boundary width. The interface chemistry has been studied successfully in a scanning Auger microprobe by Auger electron spectroscopic analysis of grain boundary fracture surfaces obtained inside the vacuum system.
Dynamic Compact Tension Testing for Fracture Toughness
Authors: Paris PC , Bucci RJ , Loushin LL 
Published: March 2009

Within this paper it is demonstrated that dynamic fracture toughness evaluation may be made by adherence to the ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-72) procedure with the single exception of test speed. The test procedure, specimen, fixturing, and instrumentation are otherwise identical to ASTM E 399-72. This makes possible direct comparisons of static, KIc values with the results of these dynamic tests.
The additional equipment required for these tests, over the normal servocontrolled hydraulic test machine typically used for KIc testing, is only the provision of a high flow and high response servo-valve with hydraulic accumulators and the capability of dynamic data storage (digital) for convenient playback into the usual X-Y recording unit.
Employing the test technique developed, dynamic fracture toughness evaluation was demonstrated on two steel alloys (302 B and A516-70) tested at room and -50° F temperatures.
Further Aspects of Fracture Resistance Measurement on Thin Sheet Material: Yield Stress and Crack Length
Authors: Sullivan AM , Stoop J 
Published: March 2009

The fracture resistance value, Kc, has been determined for a number of alloys of aluminum, titanium, and steel and found to depend inversely upon the material yield stress. During this investigation various initial crack lengths, 2ao, were employed.
Analysis of the data has disclosed that the amount of crack extension, that is, final crack length, 2ac, appears to be influenced by the initial crack length. Plotted on a log-log scale of (ao/ac) versus β=[1B(cKybσ)2], statistical analysis justifies a relationship conforming to the equation ln⁡10(ao/ac)=A-Bln⁡10β which can be transformed to (aoac)=AβB
The development of these relationships can be of real assistance in the design of a standard initial screening test for Kc.
Further Studies of Crack Propagation Using the Controlled Crack Propagation Approach
Authors: Weitzmann RH , Finnie I 
Published: March 2009

In a previous paper, a new fracture-toughness-measuring technique was presented which made it possible to evaluate the functional relationship between load and cracklength at the moment of crack initiation or arrest. It was demonstrated that this relationship is directly relatable to the strain energy release rate and experimental results were presented for a 7075-T6 aluminum alloy.
This paper presents the results of additional exploratory work as the concept is applied to more 7075-T6 aluminum, a 250 grade maraging steel, and AZ31B magnesium plate.
Measurement of KIc on Small Specimens Using Critical Crack Tip Opening Displacement
Authors: Robinson JN , Tetelman AS 
Published: March 2009

A method is described whereby on-load values of crack tip crack opening displacement (COD) can be measured at the midsection of precracked three-point bend specimens by infiltration of silicone rubber. A calibration curve relating midsection COD to clip gage displacement was derived from measurements on the silicone rubber “castings.” This calibration curve can be used to calculate midsection COD from on-load clip gage displacement and specimen geometry only, without further infiltration measurements. These values of COD have been shown to be simply related to the stress intensity factor, independent of material, as theoretically predicted.
The central region of a Charpy specimen in three-point bend has been found to remain in plane strain until well after general yield. Thus, plane strain values of COD at fracture initiation, (COD)c, can be determined from small specimens. Two initiation detection methods are described whereby (COD)c can be determined. These values of (COD)c can be used to accurately predict KIc values which agree with data obtained on larger, more expensive valid ASTM KIc specimens.
Experimental Methods to Determine Locus of Failure and Bond Failure Mechanism in Adhesive Joints and Coating-Substrate Combinations
Authors: Baun WL 
Published: March 2009

The strength of an adhesive bond is assessed by means of several physical tests in which a load is placed on the joint until failure occurs. The durability of adhesive joints is evaluated by still other techniques where the bond is tested, usually under load, in salt spray, high humidity and temperature, or other environments deleterious to the bond. Regardless of the strength of the joint, a complete description of joint performance must include how and where the bond failed.
Ion scattering spectrometry (ISS) and secondary ion mass spectrometry (SIMS) combined with scanning electron microscopy (SEM) are capable of determining the true locus of failure in an apparent interfacial bond separation. Methods using an electron beam, such as Auger electron spectroscopy (AES), are useful for analyzing evaporated metal films and the metal or alloy surface in adhesive bonds but are of limited use for examining the adhesive side of a failure, because of heating, which rapidly destroys the specimen surface. X-ray photoelectron spectroscopy (XPS), sometimes called electron spectroscopy for chemical analysis (ESCA), provides not only elemental analysis but also gives information on how the elements are combined in the adhesive, adherend, and interfacial regions. Results using these and other techniques are discussed for failure surfaces obtained by lap shear, peel test, and wedge test methods. Advantages and limitations of various methods are discussed.
Threshold Adhesion Failure: An Approach to Aluminum Thin-Film Adhesion Measurement Using the Stylus Method
Authors: Oroshnik J , Croll WK 
Published: March 2009

A detailed study of the scratch test was undertaken to determine its sensitivity, reproducibility, and soundness as a means of measuring the adhesion of aluminum films on fused quartz substrates. The complete-removal failure criterion was found to be quite subjective and often ambiguous, finally leading to the threshold adhesion failure (TAF) concept. Using the TAF approach, it was found that the scratch test is sensitive enough to discriminate between failure and nonfailure within 0.1 g of stylus loading at both low- and high-load levels. Also, the reproducibility of the mean TAF loads is excellent. In addition to the expected TAF load dependence on stylus tip radius of curvature and film thickness, it was also found that any one stylus has its own scribing characteristics which are reflected in the TAF load. The mean TAF loads are, therefore, relative measurements.
The occurrence of crescent fractures in the substrate at high-stylus loads puts an upper bound on acceptable testing loads. TAF loads are almost always well below the crescent fracture load level, but critical loads determined by the complete removal criterion (being so much higher) may have doubtful meaningfulness.
It appears that the TAF approach is measuring the lower limits, while the critical load approach is measuring the upper limits of film adherence. In either case, one obtains an estimate of the quality of film adherence, but not an unequivocal measurement of the adhesive forces.
Adherence Measurements and Evaluation of Thick-Film Platinum-Gold
Authors: Schroter S 
Published: March 2009

The fabrication of thick-film hybrid circuits using the solder system consists of screen printing conductor and resistor networks on alumina substrates and attaching other circuit elements (capacitors, discrete semiconductors etc.) to the conductor using tin-lead solder. The difficulty encountered with this technique has been that, although components are rigidly attached at the time of assembly, deterioration of the solder bonds occurs.
The objective of the investigation was to develop a suitable test method for testing incoming materials, optimizing process variables, and in-process quality control of the product.
After review of methods of conductor adherence testing, a method, pull-peel at 90 deg, was chosen which represented the worst case in actual module application. In order to hold the variables to a minimum, one standard test module was chosen for all experimental work. Part of this test module was incorporated into the design of production modules so that quality control of the product could be directly correlated with the initial testing results and with any process variables. Tests were conducted under controlled conditions which optimized all the assembly steps. Four areas have been found to have marked influence on conductor adhesion: the initial thickness of screened material, the preparation of substrate before soldering, the amount of solder used to make a joint, and the rate of cooling of the soldered joint. Implementing these controls results in a product with improved conductor adhesion.
Methods for Evaluating Adhesion of Photoresist Materials to Semiconductor Devices
Authors: Deckert CA 
Published: March 2009

A technique has been developed for making comparative evaluations of the adhesion of photoresists to various types of substrates. The technique is based on the use of a fluoride-containing etchant which exaggerates the rate of undercutting of photoresist on silicon dioxide (SiO2) surfaces and thus permits direct microscopic measurement of the relative rates of undercutting that result with various types of SiO2 surfaces and with various types of photoresist materials. Using the special etchant, the benefits of adhesion promoters such as hexamethyldisilazane are readily demonstrated. An empirical equation is given which approximately describes the shape of the undercut oxide edges, thus allowing a numerical measure of the relative adhesion (that is, resistance to etchant undercutting) of photoresist/SiO2 composites.A variation of this test can be used to detect nonuniform adhesion across a wafer surface. A photomask with a very-fine-geometry, highly recurrent pattern is used to define the photoresist, after which the wafer is etched. By using an optical microscope, the resultant dielectric/silicon substrate can be inspected very rapidly for localized adhesion variation because of the distinct color difference between areas which have or have not been undercut.
Disk Pressure Technique
Authors: Fidelle JP , Broudeur R , Pirrovani C , Roux C 
Published: March 2009

This paper presents a method of evaluating the embrittling effect of hydrogen on metals by measuring the pressure required to burst a small metal disk. The metal disks are clamped, and the system is pressurized until failure occurs. Embrittlement is expressed by the inverse ratio of the rupture pressures of a hydrogen charged disk and the rupture pressure of an uncharged disk of the same material and processing procedures.
The disk pressure test (DPT) provides evidence of other causes of embrittlement and any synergistic effects with internal hydrogen embrittlement (IHE). Other advantages of the DPT are sensitivity, versatility, rapidity, simplicity, and low cost of specimens and equipment.
Standardization of Mooney Viscometer and Oscillating-Disk Cure Meter
Authors: Decker GE , Stiehler RD 
Published: March 2009

The Mooney viscometer has been the principal instrument used to control the processability of synthetic rubber production for the past 30 years. The oscillating-disk cure meter is now becoming the principal instrument for determining the vulcanization characteristics of standard compounds of raw rubbers and compounding materials and of factory compounds used for rubber products. Therefore, a large amount of effort has been expended in their standardization. Nevertheless, both instruments which have certain similarities are affected by the following factors that still cause variability among instruments: 1. temperature of the rubber in the die cavity, 2. friction between the oscillating or rotating stem and the stationary lower die, 3. slippage at the rubber-metal interfaces, 4. the pressure on the rubber during test, and 5. scale calibration.
This paper summarizes past and recent studies on these factors and indicates from recent findings the direction for further standardization.
Measurements of the disk temperature in the oscillating-disk cure meter were made. These measurements indicated that the clearance between the oscillating or rotating stem and the lower die is critical for temperature uniformity. Also, the present design of the upper die in ASTM Measurement of Curing Characteristics with the Oscillating Disk Cure Meter (D 2084-71T) substantially reduces the rate of heat transfer to the specimen. However, the design is reasonably effective for applying pressure on the specimen which reduces slippage at the rubber-metal interfaces. Other means of applying pressure may be used. Slippage also depends on the torque at the rubber-metal interfaces. In the Mooney viscometer, torque can be reduced by decreasing the speed of the rotor or by increasing the temperature. In the cure meter, torque is most effectively reduced by keeping the amplitude of oscillation as small as practical.
Plasticity Retention Index — Its Measurement and Significance for Natural Rubber
Authors: Loke KM 
Published: March 2009

Plasticity Retention Index (PRI) of raw natural rubber is expressed as a percentage ratio of aged plasticity over unaged plasticity of raw natural rubber, the plasticities being measured on standard samples before and after the samples have been subjected to standard conditions (140°C, 30 min) of oven aging. A parallel-plate plastimeter is used in the measurement of plasticities.
This paper describes the measurement of PRI and discusses the various experimental conditions which are important to the accuracy and reproducibility of testing.
The various factors which are known to have an adverse effect on PRI are surveyed as this property of raw natural rubber is somewhat subject to change with time.
A brief outline is then given on the technological importance of PRI of raw natural rubber to the consumer.
Standards and Standardization
Authors: Stiehler RD 
Published: March 2009

Standards are practices established by authority, custom, or common consent. The practices embrace all activities of society including social, religious, educational, and technical practices. This paper deals with technical practices embodied in national or international engineering standards. A good engineering standard should: (1) stimulate competition and not restrict trade; (2) prescribe practices which conserve natural resources; (3) be abreast of technology and not be a deterrent to desirable change arising from new knowledge, new capabilities, or new environment; (4) be concise, explicit, and limited to essential provisions and requirements; and (5) be effective in achieving its purpose.
Due to the rapid increase in the number of standards both domestically and internationally, there is a movement to control proliferation through the development and use of international standards, primarily under the aegis of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC). Standards developed by ISO and IEC have now become sufficient in number to be a significant factor in international trade.
Standards development has varied considerably from one industry to another, and U. S. participation in ISO and IEC has also varied from industry to industry. ISO Technical Committee 45 on Rubber and Rubber Products has been among the ten most active committees, and U. S. participation has been exceptionally effective in it. Nearly 80 percent of the 102 standards developed by ISO/TC 45 through 1972 are in accord with ASTM Standards.
Recently, there has been a growing interest in standards for consumer products, both nationally and internationally. Eight of the 20 ISO committees most recently established deal with consumer products. There has also been a growing interest in ascertaining the ability of laboratories to obtain consistent results using standard methods, both nationally and internationally. The Standard Reference Materials issued by NBS and the NBS interlaboratory programs for testing were established for this purpose. Laboratory performance, international standardization, and the development of standards for consumer products are likely to become increasingly important in future standardization efforts.
Computerized Physical Testing of Elastomers
Authors: Stanton JL 
Published: March 2009

A small, stored-program, parallel-mode digital computer is used to process data from four tensile testing machines. Each tester is equipped with a stress encoder, strain detection system, keyboard, and teletype printer. The necessary parameters are entered on the keyboard and the specimen is positioned in the tester. A key is then depressed to start the tester and to activate the computer. The translation and transmission of the data are performed by the stress encoder and strain detection system. At the completion of the test, the data is printed in an easy-to-read tabulated format.
There are ten on-line computerized tests performed on the tensile testers. Five of the tests have alternate program routines by which the data may be processed. In addition to the on-line program routines, there are eighteen off-line routines that are used. These off-line routines are primarily performed on remote stations consisting of a keyboard and teletype printer.
The computer has decreased the chemist's data analysis time, increased the accuracy of the data, and decreased the amount of subjective data interpretation, thus resulting in greater efficiency.