bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dynamic Effective Young's Modulus of Thin Adhesive Layers in Bonded Joints
Authors: Ramakrishnan N , De AK , Suryanarayan S 
Published: February 2009

Abstract
In recent years, adhesive bonding has shown promise in replacing or supplementing conventional methods of joining such as riveting, welding, mechanical fastening, and so forth. To evaluate the dynamic characteristics of bonded structures, it is necessary to know the dynamic characteristics of bonded joints. This paper presents the development of an experimental technique to evaluate the dynamic effective Young's modulus (DEYM) of a thin adhesive layer sandwiched between metallic adherends. Considering the difficulties in measuring the strain across the adhesive layer, it was decided to avoid the measurement of strain in this technique. The joint is introduced in a cantilever beam, which causes its resonant frequency to drop because of the lower modulus of the adhesive layer. An analytical technique has been developed to evaluate its modulus from the drop in resonant frequency.
Experiments were conducted on two types of adhesives. It was observed that the DEYM is significantly influenced by the thickness of the adhesive layer. A thin adhesive layer has a higher modulus, which is less sensitive to change in the frequency. A thick adhesive layer, on the other hand, permits wider tolerances on the joint surfaces and makes fabrication easier. An optimum adhesive layer thickness has to be chosen as a compromise depending on the various joint parameters. The technique described in this paper can be used for such studies.
Introduction to Papers Presented at the Symposium on Ultrasonic Measurements of Stress
Authors: Proctor TM 
Published: February 2009

Abstract
Ultrasonic measurements of the variation of elastic modulus with stress have been done for more than 30 years. The inverse problem of measuring residual stress by ultrasonic means is still poorly understood. As a result, the measurement of residual stress by ultrasonic means has not been a successful engineering method. A symposium describing the present state of the art has been held and the written record of some of the contributors to it is presented by the following set of papers.
Ultrasonic Measurement of Axial Stress
Authors: Heyman JS , Chern EJ 
Published: February 2009

Abstract
Several applications of ultrasonic techniques are gaining acceptance for accurate preload determination of critical fasteners. In this presentation, one class of techniques based on continuous wave ultrasonics is examined in detail, with benefits and limitations discussed as they apply to accurate determination of fastener preload. The theory of acoustic propagation in strained media is reviewed as it applies to bolt geometries. Propagation measurements in these geometrics require an understanding of guided-wave effects which can influence stress determination. However, studies of the acoustic spectra of rods identify diffraction and resulting mode conversion as the main artifact for such a measurement. The acoustic spectra, obtained with a novel tone burst spectroscopy method, clearly show mode conversion effects at low frequencies to be absent at high frequencies.
Changes in the acoustic spectra are shown to accompany applied stress and suggest an instrument technique for measuring changes in fastener strain. The method, called a Reflection Oscillator Ultrasonic Spectrometer (ROUS), is discussed with an improved technique called Pseudo Continuous Wave Method (PCW) described. Data presented are obtained with the PCW for strain in several engineering materials.
Bolt geometry is shown to have an influence on the stress measurements. In particular, percent fastener length under load is evaluated for its effect on material strain measurements. A computer model predicting a linear dependence on the percent of fastener under load is verified using the PCW technique. Other aspects of bolt geometry are discussed including poor geometry bolts, bolts with transverse holes, and bolt-loading anisotropy. Experimental techniques for performing measurements on fasteners with poor geometry are discussed.
Ultrasonic Measurement of Residual Stress in Textured Materials
Authors: Arora A , James MR 
Published: February 2009

Abstract
A method is developed that determines the state of stress in a test piece in the presence of texture, that is, preferred grain orientation. This method uses frequency domain analysis of the acoustic birefringence by which an ultrasonic shear wave propagating in a material travels at slightly different velocities in the polarizations parallel and perpendicular to the axes of texture or stress. Results obtained from a Ti-6%Al-4%V block confirm that the velocity shift is linearly dependent on the amount of stress, but is independent of frequency in the case of stress as opposed to the texture. Experimental considerations involving transducer characteristics, bond (transducer to specimen) characteristics, specimen size, and signal processing are discussed in relation to the reliability and repeatability of the data.
Anharmonic Properties of Solids from Measurements of the Stress Acoustic Constant
Authors: Cantrell JH 
Published: February 2009

Abstract
The description of anharmonic properties of solids, such as thermal expansion or the interaction of thermal and acoustic phonons, involves generalized Grüneisen parameters that describe the strain dependence of the lattice vibrational frequencies. In the Debye model of specific heats the lattice vibrations are approximated by long wavelength acoustic standing-wave modes of a dispersionless elastic continuum in which the generalized Grüneisen parameters are frequency independent. Recently, a new ultrasonic measurement technique has been developed which uses such long wavelength acoustic modes to monitor axially induced accumulated static loads in threaded fasteners from a state of zero initial stress. A fundamental calibration parameter of the new technique is the stress acoustic constant defined as the fractional change in the resonant standing-wave frequency in the solid cavity per unit applied axial stress. We generalize the equations of elastic wave motion and their solutions to include nonzero homogeneous initial stresses and redefine the stress acoustic constants to include the effect of initial stress. The relationship between the newly defined stress acoustic constants and the strain-generalized Grüneisen parameters is derived, and the implications to material anharmonicity and nonlinear thermoelasticity discussed.
High Temperature Cyclic Oxidation Furnace Testing at NASA Lewis Research Center
Authors: Barrett CA , Lowell CE 
Published: February 2009

Abstract
A standardized method of testing the cyclic oxidation resistance of various alloys in static air up to 1200°C has been developed and routinely used at the National Aeronautics and Space Administration (NASA) Lewis Research Center. Test specimens are automatically raised and lowered into a resistance wound furnace for a series of fixed-interval heating and cooling cycles. Spall catchers collect the accumulated spall from each specimen. The specimens are weighed intermittently to generate specific weight change with time data. At various test times the specimens and the accumulated spall are analyzed by X-ray diffraction. A computer program is used to print out the specific weight change versus time data and the X-ray data in tabular form and to plot the specific weight change versus time data in a publishable format. The data are also organized and indexed. So far several hundred iron-, nickel-, and cobalt-base alloys have been tested using this basic procedure and will form the basis of a series of cyclic oxidation handbooks to be published by NASA. Such specific weight change/time data have been used to estimate the oxidative metal consumption by several computer modeling techniques both to rank alloys and to estimate life.
Fracture Testing in High Temperature and Pressure Hydrogen Environments
Authors: McCabe DE , Landes JD , Gradich FX 
Published: February 2009

Abstract
Fracture mechanics tests were conducted on a 2¼Cr-1Mo steel in an environment containing 6% hydrogen sulfide and 94% hydrogen at temperatures up to 727 K (850°F) and pressures to 24.1 MPa (3500 psi). A test chamber and accompanying system were designed to test under monotonically rising, sustained, and cyclic loads. This paper contains a description of the design and operation of the system developed to conduct these tests, along with a brief discussion of testing experience and types of results.
Gas Analysis Techniques for High Temperature Corrosion Testing
Authors: Kane RH , Goodell PD 
Published: February 2009

Abstract
This paper describes the application of instrumental methods of gas analysis for the on-line characterization and control of corrosive high temperature environments. By way of example, experimental techniques for the treatment of combustion products and pyrolysis and reformer environments are presented. Methods for broadening the usefulness of gas chromatography and other instrumental measurements, along with practical gas handling techniques, are discussed.
Low Temperature (650 to 700°C) Burner Rig Testing
Authors: Aprigliano LF 
Published: February 2009

Abstract
A low temperature (677°C [1250°F]) 500-h burner rig test using a fuel with 2% by weight of sulfur was made of IN939, a standard cobalt, chromium, aluminum, yttrium (CoCrAlY) coating, and a nickel, chromium, aluminum, yttrium (NiCrAlY) coating. Both the IN939 and the CoCrAlY coating were found to hot-corrode readily. The CoCrAlY coating hot-corroded by a Type 2 mechanism (low-melting point mixed sulfate), while the IN939 showed evidence of both Type 1 (sulfidation) and Type 2 hot corrosion. The NiCrAlY coating was relatively unattacked. A change in the mode of attack was noted in the CoCrAlY coating when the rig temperature dropped to 650°C (1200°F) for 24 h. The corrosion mode may have changed from one in which solid cobaltous oxide is the stable phase at the gas/scale interface to one in which solid cobalt sulfate is the stable phase.
Behavior of Aggregate in the Washington Degradation Test
Authors: Goonewardane K 
Published: February 2009

Abstract
The variations of the Washington degradation test values with particle sizes and times of agitation were studied on some samples of aggregate. The sand equivalent measuring technique was modified to read fines produced. The study has established that the Washington degradation test is a clay leaching test dependent on surface area of charge. Surface attrition also occurs. A mathematical model is proposed which agrees with the samples considered.
Modification of the Thermobalance Method of Clay Determination and Analysis of Clay Mixtures
Authors: Goonewardane K 
Published: February 2009

Abstract
The normal method of determining the clay content in a sample using X-ray/thermobalance was modified to enable a larger number of tests to be carried out simultaneously. The method was applied to study interaction effects in clay mixtures of bentonite (50% montmorillonite), chlorite, illite, and kaolinite.
Dynamic Monitoring of Liquid Systems for Particulate Contamination
Authors: Carver LD 
Published: February 2009

Abstract
Contamination control is important in many kinds of liquid systems. It may be (a) to insure a clean product during packaging, (b) to maintain the performance of a fluid power control system, (c) to monitor the effectiveness of a flushing process for cleaning parts, or (d) to assure cleanliness of photographic and chemical processing liquids. The applications are almost unlimited. The most effective control is achieved by continuous, on-stream monitoring of the flowing liquid. This paper discusses several types of monitors; what each one measures; correlation and calibration techniques; various applications; sampling and operational considerations; and some of the advantages and disadvantages.
Processing of Glass Containers for Parenteral Products
Authors: Anschel J 
Published: February 2009

Abstract
Particulate matter in parenteral solutions has been a problem not readily solved. Efforts are being made to identify and possibly eliminate existing problems by exploring available methods and instruments and by analyzing current data. The selection of glass, the methods of handling glass containers, the methods and machines for washing the containers, and the sterilization process are important areas of concern. Suggestions for standard procedures and specifications are presented.
The Removal of Stearic Acid Monolayers from Glass with Organic Solvents
Authors: Brandreth DA 
Published: February 2009

Abstract
A series of common organic solvents was used to deplete 14C-tagged stearic acid monolayers on zinc borosilicate glass. It was found that solvent water content is of key importance in determining the effectiveness of monolayer removal. Monolayer removal was rapid, with almost all removal taking place within the first 30 s.
Cleaning Borosilicate Glass for Biological Application
Authors: Pantano CG , Hench LL 
Published: February 2009

Abstract
Successful growth of tissue and organ culture in commercial glass flasks requires a cleaning pretreatment. Auger electron spectroscopy is used to characterize the effect of such treatments upon the composition of the thin surface layers which affect cell attachment. This study considers a sodium-borosilicate glass treated, in particular, by rinsing and soaking in water and acidic solutions. The results should also prove useful for understanding the cleaning of similar glass surfaces for other applications.
Empirical Formulations for the Analysis and Prediction of Trends for Steady-State Fatigue Crack Growth Rates
Authors: FitzGerald JH 
Published: February 2009

AbstractThe general characteristics of steady-state fatigue crack growth rates are discussed. An empirical formulation is described where two constants form a basic crack growth rate versus maximum stress intensity Kmax curve, which is a straight line on a log-log graph. The constants that form the base curves for various materials are correlated to Young's modulus. A third parameter that is sensitive to material alloy and environment is described and methods for obtaining this value are presented. Crack growth rate data for several stress ratios can then be projected to the basic modulus-dependent curve, where straight line scatter bands and statistical information pertaining to the overall accuracy of the formulations can be determined.
Arc Tracking in Organic Insulating Materials and the Comparative Tracking Index
Authors: Rayl M , McCarthy DC 
Published: February 2009

Abstract
One possible source of electrical failure in electronic equipment is arc tracking in organic insulating materials. Various tests have been devised to rank materials according to this property. The results of experiments evaluating the International Electrotechnical Commission test for comparative tracking index and the effects of varying certain test conditions on the resulting index are discussed.
A Technique for Measuring Load-Line Displacements of Compact Ductile Fracture Toughness Specimens at Elevated Temperatures
Authors: Mills WJ , James LA , Williams JA 
Published: February 2009

AbstractA test method developed for measuring load-line displacements in compact ductile fracture toughness (JIc) specimens at elevated temperatures was used to characterize the elastic-plastic (J integral) fracture response of Inconel® X-750 at 75°F (24°C) and ASME SA-387 Grade C steel at 75°F (24°C) and 600°F (316°C). This technique employs a rigid fixture, attached directly to the test specimen, which translates the load-line displacements outside the loading clevises where the displacements are monitored by two linear variable differential transformers (LVDT) inside the elevated temperature environment. To evaluate the proposed displacement measuring technique, displacements and values of J determined by the LVDT method were compared with those determined by the conventional clip gage method. The data obtained from the two displacement measuring techniques were in agreement. In addition, LVDT-determined displacements within the linear-elastic regime were consistent with theoretical displacements.
Plastic Flow and Fracture Under Triaxial Loading
Authors: Ehrenburg DO 
Published: February 2009

Abstract
The purpose of this paper is to develop an algebraic frame of reference for testing under triaxial loading. In the case of moderate confining pressures, certain parameters may be assumed to remain constant, which makes it possible to describe the behavior of a test specimen in terms of relatively simple mathematical equations. In the case of higher confining pressures, the paper is limited to indicating general trends and observing that several parameters approach recognizable limiting values. In the light of these limits, it is possible to predict the behavior of materials under the combined effect of extremely high confining pressure and high temperature.
Creep-Rupture Properties of Aluminum Alloy A356-T61
Authors: Holt M 
Published: February 2009

Abstract
Permanent-mold test bars of aluminum alloy A356.0-T61 were subjected to elevated-temperature tensile tests and isothermal constant-load stress-rupture tests (for lives up to 10 000 h), under the aegis of the Metal Properties Council. Rupture strength and secondary creep rate data were analyzed by the successive plotting of isotemperature and isotime curves and by the Larson-Miller procedure. A reasonable base for setting allowable stress values for design codes has been developed.
Acoustic Emission of Plain Concrete
Authors: Nielsen J , Griffin DF 
Published: February 2009

Abstract
When a specimen of engineering material is subjected to external loads, stress waves known as acoustic emissions are induced. A unique characteristic of many engineering materials that emit acoustical energy is that upon reloading the specimen does not emit acoustical energy until the magnitude of loading exceeds the prior maximum loading. This investigation was undertaken to determine if this characteristic could be used to disclose the loading history of plain portland cement concrete. The test results show that the unique characteristic is very temporary and therefore cannot be used to determine the prior maximum loading on a concrete specimen. Within a matter of hours concrete subjected to loading within its elastic limit recovers, and acoustical energy may again be released by reloading.
Random Axial Loading of Short Reinforced Laterized Concrete Columns
Authors: Adepegba D 
Published: February 2009

Abstract
The response to random loading of short reinforced laterized concrete columns was investigated by testing, under three cycles of loading and unloading, three columns cast from 1:2:4, 1:1½:3, and 1:1:2 mixes by weight and reinforced with four 12.7-mm (½-in.) diameter mild steel rods. The results obtained from the test showed that randomly loaded columns are capable of withstanding higher compressive stresses (80 to 95% cube strength) before failure than similar columns loaded to failure in one cycle. An attempt was made to discuss the inherent differences between the transformed section theory assumed for an “elastic” concrete component of a composite column and the theory applicable to a “viscoelastic” concrete, which laterized concrete approximates.
Influence of Material Property Variations on the Assessment of Structural Integrity of Nuclear Components
Authors: Chirigos JN , Meyer TA 
Published: February 2009

Abstract
The question, “Where can the generation of new material property data reduce overly conservative design in reactor systems?” presently exists in the nuclear industry. The question is answered by identifying where conservatism exists relative to determining material property variations. Several areas are reviewed to identify conservatism and the sensitivity of structural integrity evaluation results to the property variations. The areas reviewed were fluence dependence of the transition temperature, fracture toughness, the drop in upper shelf toughness, the arrest toughness, the material thermal properties, and the fatigue crack growth rate.
Fatigue Crack Arrest at Low Stress Intensities in a Corrosive Environment
Authors: Nordmark GE , Fricke WG 
Published: February 2009

Abstract
Crack opening displacement measurements and scanning electron microscope observations were used to investigate the cause of fatigue crack arrest that occurred in compact specimens of several aluminum alloys at low stress intensities in simulated sump water. The observations for 7475-T7351 specimens indicate that the crack arrest resulted from a progressive buildup of corrosion product on the crack surface.
Determining Filtration Efficiency by Comparing the Particle-Size Distribution in the Feed Stream to that in the Filtrate
Authors: Johnston PR 
Published: February 2009

Abstract
Exactly how the investigator should make the comparison between the particle-size distribution in the feed stream to that in the filtrate is the subject of controversy between those who determine the cumulative number of particles versus particle diameter and those who determine the number of particles in each of many diameter ranges. The present discussion, based on the number of particles in each diameter range, addresses the question, “What width of a diameter range should be considered?”
Some Parameters Influencing the Release Pressure of Reverse-Buckling Safety Disks
Authors: Beese JG 
Published: February 2009

Abstract
In recent years safety disks based on the principle of the reverse buckling of a spherical, metallic cap have been developed. In this paper the influence on the disk-buckling pressure of (1) the orifice diameter of the flange-holding ring and (2) heat treatment of the dome before assembly is examined. It is found that both orifice diameter and heat treatment influence the value of the reverse-buckling pressure.
Powder-Cushion Gripping to Promote Good Alignment in Tensile Testing
Authors: Lange FF , Diaz ES 
Published: February 2009

Abstract
A tensile testing technique utilizing a powder-cushion between the specimen/grip surfaces has been devised and tested. Bending strains associated with this gripping technique have been determined as a function of load with a buttonhead specimen instrumented with nine strain gages. Experiments with eight different powders showed that lubricating powders such as graphite and boron nitride are more effective in producing good alignment, with graphite considered superior. Alignment obtained with the graphite powdercushion is comparable with that obtained with more complex devices and procedures.
A Hydrostatic Stress-Sensitive Relationship for Fatigue Under Biaxial Stress Conditions
Authors: Mowbray DF 
Published: February 2009

AbstractFailure criteria for elastic- and plastic-strain controlled fatigue under biaxial loading are proposed. The criterion for elastic strain is defined in terms of the equivalent strain from the distortion energy theory and that for the plastic part as the corresponding equivalent plastic strain, but modified to include a function of the hydrostatic stress component. These criteria are incorporated into the derivation of a relationship for fatigue life in terms of the principal strain amplitude, analogous to a conventional form for uniaxial loading. An analysis of some limited available data from the literature shows the potential predictive capability of the relationship.