bluuebunny/crossref_metadata_2025 huggingface dataset:
A New Technique for Fracture Characterization of Ceramics at Room and at High Temperature
Authors: Pastor JY , Planas J , Elices M
Published: February 2009

A new technique for performing stable tests in ceramic materials is analyzed in depth. The new feature consists in using an analog output of a laser metrology apparatus that measured the crack mouth opening displacement (CMOD), as the feedback signal to control a servohydraulic testing machine. In this study, we go deeply into the analysis of the experimental parameters that control the performance of this technique. Finally, the temperature dependence is shown for the fracture parameters obtained from stable tests of single-edge-pre-cracked-beam specimens (SEPB) of 3 mol% Y-TZP.
Optimization of Lime Content for Fly Ash
Authors: Sivapullaiah PV , Prashanth JP , Sridharan A
Published: February 2009

Abundant quantities of fly ash have been produced by thermal power plants situated all over the world. Many applications of fly ash depend upon its pozzolanic reactivity. This reactivity depends upon many factors, including lime content. Many fly ashes show marked improvement with the addition of lime. However, for every fly ash, there is an optimum lime content for its maximum reactivity. There is no well-established simple test to determine the optimum lime content. In this paper an attempt is made to use a simple physical and physico chemical test to determine the optimum lime content. The principle behind the use of a pH test, liquid limit test, and free swell index test to determine the optimum lime content has been explained. All the methods predict nearly the same optimum lime content and correlate well with that determined by the strength test.
Analysis of the Peel Test: Prediction of Adherend Plastic Dissipation and Extraction of Fracture Energy in Metal-to-Metal Adhesive Joints
Authors: Moidu AK , Sinclair AN , Spelt JK
Published: February 2009

The peel test has been widely used for the mechanical measurement of the adhesion phenomenon. However the proportion of the energy input dissipated plastically within the adherend is a major concern in analyzing peel test data. This paper presents an analytical approach to predict the adherend plastic dissipation in the peel test for metal-to-metal adhesive joints, thereby allowing the fracture energy to be extracted from the test data using an energy balance approach. Expressions are developed for the deflection of an elastic-plastic beam on an elastic foundation, which is then combined with known solutions for the deformation of an elastic-plastic strip under large displacement. The model takes into account both the adhesive and adherend compliance effects on the plastic dissipation. Numerical predictions of the model are presented to gain insight into the effects of adherend properties and peel angle on plastic dissipation in the peel test. It is demonstrated that experimental results with various adherend properties and peel angles are consistent with the predictions of the model. An important conclusion is that for typical structural adhesives, the effects of plastic dissipation may be kept small by using a relatively low yield strength alloy with a thickness much smaller than the critical thickness at which the plastic dissipation effect is a maximum. The extraction of the fracture energy from the test data is also discussed with regard to the mixed-mode nature of the peel test.
A Reversing Direct Current Potential Drop System for Detecting and Sizing Fatigue Cracks along Weld Toes
Authors: Yee R , Lambert SB
Published: February 2009

Steel welded T-joints with 102 mm thick base plates were fatigue tested in three-point bending. A reversing direct current potential drop (DCPD) system was used to detect the initiation of multiple surface cracks along the transverse weld toes of these joints and to monitor the size and shape of fatigue cracks that developed from these cracks. Potential drop readings were obtained by fixed probes straddling the weld toes and normalized with respect to potential drop readings from a remote reference probe. The normalized potential drop readings from each probe were related to the local crack depth by two-dimensional (2-D) calibrations derived by boundary element analyses and the foil analogue method. The fixed-probe arrangement was able to detect 0.4 mm to 1.0 mm deep surface cracks along the transverse weld toes of the T-joints. The 2-D calibrations were able to predict the crack depth at the deepest points of these cracks to within ±10%.
A Compact Testing System for Dynamic Fracture Studies
Authors: Marur PR , Simha KRY , Nair PS
Published: February 2009

Development of a compact instrumented impacting apparatus for dynamic fracture studies designed on the lines of a swing pendulum machine is described. Salient features of the system and instrumentation calibration procedures are presented. The dynamic characteristics of the system are explained with the aid of a simple inertial model. Results of dynamic fracture experiments conducted on aluminum 6061 alloy and polymethylmethacrylate (PMMA) are discussed.
An Improved Method for Threshold Fatigue Crack Propagation Testing on an Electromagnetic Resonance Type Machine
Authors: Nishijima S , Matsuoka S , Ohtsubo S
Published: February 2009

An improved technique of fatigue crack propagation testing is proposed for the determination of threshold stress intensity range ΔKth using an electromagnetic resonance type testing system. A special device is used to compensate for the change of specimen compliance during the test. It is composed of a set of traverses mutually hinged at one end between which an elastic body and a specimen are mounted in parallel, respectively, at predetermined distances from the hinge, so that the resultant composite compliance of the device is designed to be practically insensitive to the change of specimen compliance. A series of ΔKth measurements was performed at various load ratios for six steels of various strength levels, using small compact type (CT) specimens of 25 mm width and 5 mm thickness, under combined control modes of the applied load and the backface strain of the specimen. The use of the compliance stabilizing device improved markedly the controlling stability of the testing machine and facilitated the determination of ΔKth value under autodecreasing ΔK conditions at high load ratios. The obtained ΔKth values from the experiments were in excellent agreement with those found in the literature.
A New Transducer to Monitor Fatigue Crack Propagation
Authors: Liaw PK , Hartmann H-R , Logsdon WA
Published: February 2009

A sputter deposition technique has been successfully used to fuse atomically a high-temperature DC transducer, in the form of a thin film Krak-Gage®, directly onto a test specimen for developing fatigue crack propagation rate data. The rates of fatigue crack growth measured by this technique are in good agreement with those measured by the compliance method at 288 and 427°C (550 and 800°F). The data acquisition and analysis are automated by interfacing with a computer, which saves costly labor associated with fatigue crack growth tests. This new development, based on thin film sputtering technology, is expected to enable researchers to conduct fatigue and fracture mechanics testing in various adverse high-temperature environments.
JIc Measurement Point Determination for HY130, CMS-9, and Inconel Alloy 718
Authors: Matthews JR , West GD
Published: February 2009

Determination of the elastic-plastic fracture toughness for three medium strength materials of varying ductility has been carried out. The materials in order of decreasing ductility are HY130 steel, CMS-9 steel, and Inconel Alloy 718. A survey of measurement-point techniques for JIc has been incorporated in the study to evaluate the effect of ductility on the determination of the elastic-plastic fracture parameter and subsequent estimation of the elastic fracture toughness KIc.
Short-Range Ordering in Nickel-Chromium Thermocouple Alloys
Authors: Pollock DD
Published: February 2009

A short-range, lattice-ordering mechanism has been used extensively to explain the anomalous thermoelectric properties of such alloys as Chromel® and Nicrosil®. This concept appears to have had its origin in early crystallographic work that postulated this mechanism to explain experimentally observed changes in the relative electrical resistance of nickel-chromium alloys. Later crystallographic work, confirmed by several additional investigators, shows no evidence for the existence of short-range order in nickel-chromium alloys containing less than 25 At % Cr. Other investigators, reviewing the short-term thermoelectric deviations of these alloys, describe this mechanism as “much circumstantial evidence of a hypothesis that the short-term emf changes are due to short-range ordering in the Ni-Cr atomic structure of the Type KP thermoelement.” Since short-range ordering has not been established as being responsible for the thermoelectric properties of nickel-chromium alloys, this mechanism may not arbitrarily be considered as the sole rationale for their behaviors.
Variances in Sampling Streams of Coal
Authors: Rose CD
Published: February 2009

Beginning with the postulate that the serial correlation in an infinite population is invariant with respect to segment mass, expressions are developed for variance as a function of mass and expected variance of the mean using random, stratified random, or systematic sampling of a linear population. The expression for variance as a function of mass is shown to agree well with data from one coal experiment and to be the same as an empirical formula developed from agricultural experiments.
A Constant Amplitude Fatigue Study of an Aluminum Powder Metallurgy Alloy
Authors: Santner JS , Campbell G
Published: February 2009

Three test conditions were chosen to conduct multiple constant amplitude fatigue tests on a powder metallurgy (P/M) aluminum alloy. These test conditions were chosen to produce mean target fatigue lives near 1, 50, and 200 kilocycles. A statistical rule was used to select specimens for fractographic examination. Two product forms, a forging and an extrusion, were tested in both the L and L-T orientation. The forging has approximately an 8% lower yield strength and a 20% higher reduction in area than the extrusion. At the 1-kilocycle target fatigue life, the more ductile forging has a statistically better fatigue performance. Beyond 10 kilocycles, the higher strength extrusion appears to have a longer life, although this was not statistically verified. It is suspected this is because of the increased variance at these longer fatigue lives. Further testing is required to verify this point. Additional testing of the extrusion showed that if the data are fitted to a Weibull model, the P/M extrusion has a vastly different failure rate than reported for ingot metallurgy (I/M) products. A decreasing failure rate for the P/M extrusion was verified with a nonparametric test. The difference in failure rates may be related to the finer grain size and constituent particle size found in P/M aluminum products. Additional study is needed to verify this hypothesis.
Contextual Effects in Category Ratings
Authors: Lawless H
Published: February 2009

In sensory evaluations of consumer products, panels of observers often use ratings on category scales to assess differences in the sensory characteristics of products. However, use of rating scales, especially by naive observers, is prone to several biases that may act to distort such judgments. Observers learn about the range and distribution of sensory values for a given characteristics, and then adjust their judgments of that characteristic so that a full range of the available categories are assigned, and so that the categories are assigned with roughly equal frequency. Unless trained and given a constant frame of reference, observers use category scales as relative, not absolute, scales of judgment, adjusting their internal strandards based upon the recent contexts within which a product was presented.
Certificate Values—What Do They Mean and How They Should Be Used
Authors: Ku HH
Published: February 2009

The meanings of commonly used uncertainty statements associated with certified values of Standard Reference Materials are explained. In particular, the implications of these statements are interpreted in nonstatistical terms for the users.
Deconvolution, Derivation, and Smoothing of Spectra Using Fourier Transforms
Authors: Cameron DG , Moffatt DJ
Published: February 2009

Most spectrometers are now digitized, and many include a fast, programmable minicomputer. This has opened up the possibility of routine use of sophisticated data processing methods using Fourier transforms. This paper first covers the properties of spectral lines and their Fourier transforms. It then develops the method of Fourier deconvolution, shows the similarity of derivation, and concludes with a section on smoothing using transforms.
Multicomponent Infrared Analysis Using P-Matrix Methods
Authors: Brown CW
Published: February 2009

Spectroscopic data for single- and two-component systems showing strong deviations from Beer's law have been fitted with the following functions: Beer's law with first order term only, Beer's law with zero and first order terms, and a nonlinear function. The mathematics for performing the analyses are developed and applied to actual systems. Considerable improvements are noted with the more complex functions. The advantages of using a computer for processing the data include the ability to handle the more complex functions and the matrix manipulations. It is shown that these advantages ease the requirements for selecting analytical wavelengths.
Methods for Determination of NH4+-N, NO3−-N and Organic Forms of Nitrogen in Wastewaters
Authors: Ho CL
Published: February 2009

Methods of steam distillation for the determination of NH4+, NO3−, NO2−, and organic forms of nitrogen in wastewaters are described. Oil and grease derived from petroleum and coal processing must be removed by successive extraction with benzene and cyclohexane before distillation begins. To prevent biological nitrogen transformation and assimilation, preservation of water samples with a suitable preservant, such as chloroform, and subsequent analysis of samples within one week are recommended. In the procedure, NH4+ was steam distilled with a specified amount of magnesium oxide, NH4+ + NO3− + NO2− with magnesium oxide plus Devarda's alloy in 3 to 4 min. Nitrite was effectively destroyed with sulfamic acid, thus, allowing its quantitative measurement by difference before and after sulfamic acid treatment, which is before steam distillation. Organic forms of nitrogen in protein, oil brine, and coals were quantitatively converted as NH4+ by a micro-Kjeldahl method at 360°C on a temperature controlled block (Technicon BD-40) digester for 1 to 5 h after clearing. Ammonium recovered by steam distillation is measured either by titration or by a spectrophotometric method. The latter is favored because of its high sensitivity and because only a small amount of sample is required. The methods are applicable to waters of various types. Interference by organic and inorganic substances in water has rarely been encountered.
Determination of Arsenic in Geologic, Biologic, and Water Samples by Flameless Atomic Absorption Spectrophotometry and Inductively Coupled Plasma Atomic Emisson Spectrometry Following Distillation
Authors: Ho CL , Tweedy S , Mahan C
Published: February 2009

A distillation method was used to separate arsenic trichloride from interfering substances in the presence of hydrochloric acid, hydrobromic acid, and hydrazine sulfate. Arsenic in distillate was determined by flameless graphite furnace atomic absorption spectrophotometry (GFAAS) and inductively coupled plasma atomic emission spectrometry (ICP-AES). Liberation of arsenic trichloride by distillation was not inhibited by NO3−, Ni+2, or other substances encountered in geological, biological, and water samples. Free nitric acid must be neutralized with potassium carbonate or removed by evaporation in the presence of sulfuric acid at 160°C (320°F) before arsenic trichloride distillation. Geochemical reference samples, U.S. Environmental Protection Agency (EPA) water standards, geological samples, and water samples were analyzed. Results of distilled arsenic trichloride in all reference samples agreed with the reported values. Without distillation, agreement with reported values was obtained only in water samples containing low matrix substances.
Pilot Study for U.S. Geological Survey Standard Reference Water Samples for Pesticides
Authors: Friedman LC , Fishman MJ , Boyle DK
Published: February 2009

The U.S. Geological Survey has been preparing and maintaining a library of standard reference water samples for inorganic constituents for 19 years. Recently, a pilot study was conducted to see if the reference-sample program could be expanded to include pesticides and other organic materials. Two samples containing organochlorine and organophosphorus insecticides, and chlorophenoxy acid herbicides were distributed to a number of laboratories in the United States. One of the samples also contained polychlorinated biphenyls. Interlaboratory data obtained from these round robin studies are presented with intralaboratory information on long-term stability.
Application of Inductively Coupled Plasma Atomic Fluorescence Spectrometry in the Steel Industry
Authors: Lancione RL , Drew DM
Published: February 2009

ICP atomic fluorescence spectrometry has been used to analyze a variety of materials that include an iron ore and a blast furnace slag, as well as low alloy and stainless steels. The technique provides selectable simultaneous multielement analysis with good detection limits. Spectral interferences and background effects are generally avoided and no computer, monochromator, polychromator, or complex scanning mechanisms are required. An examination of the effect of an iron matrix on detection limits shows a small but measurable degradation for aluminum and chromium. The intensity-concentration relationship exhibits strict linearity over three to four orders of magnitude measured from the lowest determinable concentration. The analytical results for aluminum, cobalt, chromium, copper, manganese, molybdenum, nickel, and silicon are in good agreement with certified values.
Advances in Atomic Absorption Graphite Furnace Analysis
Authors: Barrett P , Barnett W , Fernandez F
Published: February 2009

The literature documents a succession of individual improvements over previous graphite furnace technology. These individual improvements include graphite tubes with better pyrolytic coatings, Zeeman background correction, rapid heating of the graphite tube, the L'vov platform, faster instrumental electronics, and matrix modification. Any one of these developments will improve certain analyses. However, taken together as an integrated system, the total is more than equal to the sum of the parts. The integrated system, known as the stabilized temperature platform furnace technique, provides the analyst with capabilities not available on previous graphite furnace systems. Analyses are conducted differently, methods are developed differently, and the results are more predictable.
Physical Properties of Densified Refuse Derived Fuel
Authors: Eimers JL , Vesilind PA
Published: February 2009

The need for and a description of eight draft standards for describing physical properties of densified refuse derived fuels are described. These draft standards include: collecting and dividing a gross sample of densified refuse derived fuel (dRDF), air drying, measuring the density of individual particles and bulk density, measuring the particle size distribution and the durability of the particles, and measuring total residual moisture and water adsorption. These draft standards are being developed by ASTM Committee E-38 on Resource Recovery. The precision of the test methods is also reported.
A Hierarchical Approach to the Measurement of Changes in Community Structure Induced by Environmental Stress
Authors: Boyle TP , Sebaugh J , Robinson-Wilson E
Published: February 2009

A new index of dissimilarity is proposed to measure changes in community structure caused by environmental stress. A new statistical algorithm was also devised to test the similarity or dissimilarity between two communities. This procedure tests the mean dissimilarity within two communities against the mean dissimilarity between the same communities. These new indices are used along with other traditional indices of community structure in a proposed hierarchical scheme for testing different degrees of changes in stressed communities. Several examples illustrate that the procedures proposed give a more interpretible comprehensive analysis than the use of a limited set of indices.
Absolute Measurements of Ultrasonic Attenuation Using Damped Nondestructive Testing Transducers
Authors: Papadakis EP
Published: February 2009

This paper reviews the method for making absolute ultrasonic attenuation measurements by means of nondestructive testing transducers and liquid buffer columns or solid buffer rods. The principle is that the transducer must be separated from the specimen so that the transducer cannot influence the echoes in the specimen. Then the attenuation coefficient in the specimen and the reflection coefficient at the buffer/specimen interface can be calculated from the amplitudes of the first three echoes in the buffer/specimen system. For absolute measurements, the amplitudes must be corrected for ultrasonic beam spreading (diffraction). The theory of the measurements and the corrections is recapitulated, and experimental examples are given showing the utility of the method. Experimental techniques are also recapitulated.
Quantitative Relations Among Measures of Ductility in Planar and Through-Thickness Tension Tests of 12.8-mm-Diameter Specimens
Authors: Ludwigson DC , McDonald MM
Published: February 2009

The distribution exponent (DE) is a measure of a material's ability to transfer its inherent ultimate ductility (as measured by reduction of area RA) into practical maximum extension in the direction of forming forces (as measured by elongation, in 50.8 mm [2 in.], EL). The computation, nature, and utility of the distribution exponent are discussed herein.
Single Specimen Fracture Toughness Testing of Low Strength Steel Plate Using The Direct Current Electrical Potential Method
Authors: Doig P , Abbott KR
Published: February 2009

The direct current electrical potential method for monitoring of crack length during fracture toughness JIc testing of low strength steels using the crack resistance curve approach is described. The experimental precautions and data processing procedure required for its application are described and discussed. Experimental data obtained from side-grooved, Charpy geometry specimens manufactured from a boiler plate steel are presented.
Determination of Fracture Toughness of a Material That Exhibits Pop-In Behavior
Authors: Putatunda SK , Banerjee S
Published: February 2009

Fracture toughness of a material that undergoes pop-in crack extension was measured in two different heat treated conditions by a new procedure proposed in a recent publication. It is shown in this publication that the new procedure gives a size independent plane strain fracture toughness KIc value in thin and wide specimens prepared from relatively tough material. The present investigation examines the effect of width and the applicability of various approaches to fracture toughness measurement procedures, such as the new procedure, ASTM Test Method for Plane-Strain Fracture Toughness of Metallic Material (E 399), KIc, the ductile fracture toughness value JIc, and the crack growth resistance R curve, to a material that undergoes pop-in crack extension. The results show that whereas the new procedure can give a meaningful, reliable, and size independent fracture toughness even for a material that undergoes pop-in crack extension, the other methods, such as R curve, JIc, Kpop, or ASTM E 399 are inapplicable. The new procedure also shows that the K-KIc approach can be used in specimens whose thickness is 4.5 times less than that required by ASTM E 399.
Determination of Fracture ToughnessJIc Under Quasi-Static and Dynamic Loading Conditions Using Wedge Loaded Specimens
Authors: Bayoumi MR , Klepaczko JR , Nabil Bassim M
Published: February 2009

A study of the variation of fracture toughness of American Iron and Steel Institute (AISI) 1045 (Unified Numbering System [UNS] G10450) steel in the annealed condition, which exhibits elastic-plastic behavior at the crack tip, with loading rates ranging from quasi-static to dynamic conditions was undertaken. A wedge loaded compact tension (WLCT) specimen geometry was used in both testing conditions. The onset of crack propagation was detected using a strain gage mounted near the crack tip. The fracture parameter JIc decreases by about 50% when the loading rate ˙KI increases from 0.5 to about 106 MPa · m½ s−1. The measured values of JIc using WLCT specimens were confirmed from previous data on this material using standardized three-point bending specimens as well as from evaluation of JIc from stretch zone width measurements using scanning electron microscopy of the fracture surface of the WLCT specimens.
Interstitial Carbon and Nitrogen Effects on the Cryogenic Fatigue Crack Growth of AISI 304 Type Stainless Steels
Authors: Tobler RL , Reed RP
Published: February 2009

Constant-load-amplitude fatigue crack propagation (FCP) rate measurements are reported for AISI 304 (Unified Numbering System [UNS] S30400) type stainless steels having variable carbon-plus-nitrogen (C+N) contents. Rates at stress-intensity factors from 20 to 70 MPa ·m½ were measured using 25-mm-thick compact specimens. The Fe-18Cr-10Ni steels tested exhibited partial martensitic phase transformations during tests at 76 and 4K, but not during tests at 295 K. The behavior varied considerably with composition: at high C+N contents (0.187% by weight or greater) the FCP resistance was lower at 4 than at 295 K, whereas at low C+N contents (0.067% by weight) the FCP resistance was significantly higher at 4 than at 295 K. The improved cryogenic behavior at low C+N contents was associated with a transition in failure micromechanisms.
Crack Growth in High-Density Polyethylene Pipes
Authors: Gradin PA , Arve E
Published: February 2009

To investigate the applicability of a theory developed by Schapery to crack growth in thermoplastic pipes, experiments were performed on high-density polyethylene (HDPE) pipes. In the experiments the pipes (with existing through-the-thickness cracks) were loaded by an internal pressure and the time-dependent crack length was measured. This was done at three different temperatures, 20, 30, and 80°C and for two cases of crack orientation, axial and circumferential. It was observed that the theory agreed reasonably well with the experimental data.
Effects of Mechanical Drying on Styrene-Butadiene Rubber
Authors: Hall ML , Trott GF
Published: February 2009

In the commercial production of styrene-butadiene copolymers, the finished product is dried by oven-type dryers or by mechanical-type dryers. Our goal was to determine if, and to what extent, the severe conditions of mechanical drying effect the viscoelastic properties of the copolymer. It was determined that mechanical drying added to the “shear history” of the polymer and contributed to premature breakdown. Furthermore, the rheological properties of the polymer are altered in a manner that suggests the presence of long-chain branching. These alterations persist in the compounded stock as variations in the elastic properties of the uncured material. The shear history of a compound is important to its processibility. This history begins at the production of the base polymers and may be of concern to the user.
Estimation of End Corrections in Capillary Flow
Authors: Colbert GP , Ziegel KD
Published: February 2009

A simple method is described for estimating end corrections in capillary flow. It is based on Bird's technique for predicting recoverable shear strain from viscosity data and using these predicted values in the Tanner equation. A shortcoming of the method is the technique for correcting the Tanner equation for capillary length to diameter ratio so that this method is not satisfactory for capillaries shorter than a L/D ratio of eight. Using longer dies, good agreement is seen between values corrected by this method and those corrected by the Bagley method. Since this method uses data from a single die, it should be of interest to industrial technologists concerned with the time and effort involved in correcting data via the Bagley method.
Improvement of Standard Rheological Tests for Better Material Characterization
Authors: Koopmann RK , Kramer H
Published: February 2009

Details for two new tests for rheological material characterization are given resulting from the development of standard rheological tests:

1. The well-known Mooney-viscosity test is improved by automatically adding a relaxation test. Thereby, information on elastic material behavior is obtained in a very simple and fast manner. It is especially useful for rubber compounds.

2. The parallel plate compressive plastometer or Defo test gives information on viscous and elastic material behavior in the compressive and recovery phases of the test. Intensive developments of the instrument and changes and additions in the test procedure resulted in a relatively simple test, giving a number of accurate rheological test data for each quality including the flow exponent. It is especially useful for testing rubber polymers.

Typical results from several years experience are given.
Biaxial Test Method for Characterization of Fabric Materials Used in Permanent Fabric Roof Structures
Authors: Mott R , Huber G , Leewood A
Published: February 2009

An experimental investigation was conducted to develop a test method and hardware for the purpose of characterizing the material behavior of coated glass fabrics for application in large roof structures. Because of the biaxial nature of stresses in fabric structures, an internally pressurized cylinder specimen was designed for use in a hydraulically actuated (MTS) testing machine. Biaxial cylinder fabrication and appropriate testing procedures were developed. Stress-strain and strength characteristics were determined for various fabric material types and material lots. Biaxial monotonic, step loading, stress rupture, and dynamic fatigue loading conditions were studied. Combined biaxial tensile plus shear loading were assessed by testing cylinders under biaxial and superimposed torsion loading conditions. The strength characteristics of damaged fabric materials were also extensively assessed.
A Method for the Defined Fatigue Precracking of Round Notched Bars
Authors: Eisele U , Roos E , Silcher H , Zimmermann C
Published: February 2009

This paper is concerned with the method of crack length controlled prefatiguing of notched round tension specimens. Since a direct optical analysis of the crack length in the present specimen is not possible, the change in the specimen stiffness is used to determine the crack depth. For this purpose, the deflection of the specimen is measured by laser technique during prefatiguing under reversed bending stressing. Comparing the measurement data with parameters determined by calculation from the transfer matrix method enables the crack depth to be determined on-line at any time of the prefatiguing process.
An Optical Test Method for Measuring Biaxial Deformations
Authors: Polvani RS , Reeve CP , Veale RC
Published: February 2009

A new and simple method is described for the measurement of biaxial deformation with a resolution of 0.025 μm (1 μin.). The basis for this technique is the use of an optical extensometer.
Comparison of the Kesternich Sulfur Dioxide Test with Industrial Atmospheric Corrosion Tests of Zinc-, Aluminum-, and Al-Zn-Coated Steel Sheet
Authors: Berke NS , Townsend HE
Published: February 2009

Results of the Deutsches Institut für Normung (DIN) Kesternich sulfur dioxide test (DIN 50018) are compared with those of long-term industrial atmospheric exposure tests of sheet steels coated with zinc, aluminum, and Al-Zn alloy coatings. According to the Kesternich test results, Al-Zn and zinc coatings provided sacrificial protection to the steel substrate whereas the aluminum coatings did not. Durability was highest for the 55% Al-Zn and aluminum coatings. Qualitatively, these results are in good agreement with those of atmospheric tests. However, durability of 4% Al-Zn and 7% Al-Zn in the Kesternich test was better than two times greater than that provided by zinc coatings. This finding does not agree with the results of long-term atmospheric tests in an industrial environment. These comparisons demonstrate that the Kesternich test provides a useful qualitative ranking of these coatings but should not be relied on to quantitatively predict coating life.
Algebraic Approximations of Stress-Strain Curves for Kevlar-Reinforced Composites
Authors: Papirno R
Published: February 2009

Stress-strain curves for Kevlar-cloth reinforced epoxy composites have been approximated by two-part analytic functions. Autographic test records are digitized using a computer-assisted procedure, and the digitized data are automatically processed using regression analyses routines. Tensile data are best approximated by a bilinear function; compressive data are best fit to either a parabolic-linear or a parabolic-exponential function. The errors of fit of the analytic functions to the test data are smaller than the experimental errors of the test. One application of the technique is for economic computer storage of stress-strain curves. A maximum of four constants and a one-digit code number are all that are required to store an entire stress-strain curve. Also, average stress-strain curves can readily be obtained and various moduli are easily calculated.
Temperature of the Unexposed Surface of Fire Resistance Test Specimens
Authors: Harmathy TZ
Published: February 2009

Techniques of measuring the temperature of the unexposed surface of fire test specimens in ASTM Fire Tests of Building Construction and Materials (E 119) (or ULC S101) are critically reviewed. It is suggested that the present technique of measurement and the temperature criterion of failure be revised so as to facilitate the computer simulation of fire resistance tests.
The Effect of Fire Fighting Media on the Mechanical Properties of Steel Bars
Authors: Naga SAR
Published: February 2009

This paper presents an experimental investigation on the effect of cooling methods and means of fire extinguishing on the mechanical properties of steel bars used in reinforced concrete if subjected to a heat source. By simulating the heating effect of possible fire on the steel bars, an experimental plan has been made to include cases in which the bars may pass metallurgical phase transformation. Results indicate that the cooling of steel bars by means of water largely affects the mechanical properties especially if specimen temperatures are greater than the critical temperature compared with other cooling techniques, which are air or sand. The usual practice of extinguishing fire and cooling steel bars with water should be reconsidered as it increases the bars' hardness and ultimate tensile strength at the expense of reducing ductility. This makes the steel bars' properties less than the desired mechanical properties in building construction.
Influence of Gage Dimensions on Elongation Values for Type 316 Stainless Steel
Authors: Mathew MD , Mannan SL , Rodriguez P
Published: February 2009

Different standards such as those of ASTM, Indian Standards Institution (IS), Association Francaise de Normalisation (AFNOR), British Standards Institution (BS), International Organization for Standardization (ISO), and Deutsche Industrie-Normen (DIN), specify different dimensions and relationships between gage length and cross-sectional area for the standard and proportional tension specimens of various geometries. In this investigation a systematic attempt has been made to assess the influence of varying gage length, width, and thickness of rectangular tension specimens on the elongation values for American Iron and Steel Institute (AISI) Type 316 (Unified Numbering System [UNS] S31600) stainless steel. The ratio of gage length to the square root of cross-sectional area is found to be an appropriate parameter for correlating total elongation with specimen dimensions. Conversion relationships have been obtained between total elongation and gage dimensions for 316 stainless steel.
User Requirements and Performance Specifications for Explosive Vapor Detection Systems
Authors: Lucero DP
Published: February 2009

A preliminary list of explosives vapor detection system user requirements is prescribed for three basic applications: (1) Processing—item and personnel examination at a processing station; (2) searching—area search and examination by portable, semiportable, and stationary systems; and (3) monitoring—enclosure atmosphere monitoring for explosive vapors. The user requirements common in relative importance to each application are examination or processing rate, maximum allowable false- and missed-alarm probability, and operator training level. For specific applications, the more important requirements are those related to weight, size, and power for area search, and unattended operation for enclosure monitoring applications. The user requirements are essential in establishing the detection system performance specifications, engineering design goals, and in effective design trade-off management.
Recent Advances in Ion Mobility Spectrometry for Explosives Vapor Detection
Authors: Spangler GE , Carrico JP , Campbell DN
Published: February 2009

The detection of explosives with ion mobility spectrometry (IMS) using reactant ion (background) subtraction techniques and chloride ion/molecule reaction chemistry is discussed. Data are presented for dinitrotoluene (DNT), trinitrotoluene (TNT), RDX (cyclonite), Composition B, and dynamite. Using a membrane inlet system, a man-portable IMS detector system is described which can be used as a point sampler with these techniques.
The Fracture Toughness of Beryllium
Authors: Conrad H , Hurd J , Woodard D
Published: February 2009

Data on the fracture toughness of beryllium obtained by the authors and that available in the literature are reviewed. The effects of test method, chemistry and microstructure, temperature and strain rate, and fracture modes are discussed. The available data suggest that the fracture toughness of both hot pressed and sheet beryllium is proportional to the product of the true fracture stress and true fracture strain. A rationale for this correlation is developed on the basis of the Griffith-Orowan fracture equation. The effects of temperature and strain rate on the fracture toughness of beryllium sheet follow an Arrhenius-type relation which is in accord with that for prism slip.
Crack Toughness Evaluation of Hot Pressed and Forged Beryllium
Authors: Jones MH , Bubsey RT , Brown WF
Published: February 2009

Fracture toughness tests at room temperature were made on three-point loaded beryllium bend specimens cut from hot pressed block and a forged disk. These specimens had plane proportions conforming to ASTM E 399 and covered a thickness range of from 1∕32 to ½-in. Two sets of bend specimens were tested, one having fatigue cracks and the other 0.5 mil radius notches. During each test, records were made of crack (or notch) mouth displacement and electric potential vs applied load. One objective of the investigation was the development of techniques to produce fatigue cracks in accordance with the procedures specified in ASTM E 399. This objective was achieved for the hot pressed material. In plane cracks were not consistently produced in the specimens cut from forged stock.

Results of the fracture toughness tests showed that specimens with fatigue cracks had considerably lower values of Kmax than those with sharp machined notches. Various anomalies were observed in the behavior of the beryllium specimens from hot pressed stock. Among these were nonlinearities in the load-displacement records in what was expected to be the elastic range, negative crack mouth displacements on unloading from this range, and a decrease in electrical potential with increasing load which was recoverable on unloading. While valid KIc values could not be established, the data indicate that for practical purposes a value of about 10 ksi-in.½ would characterize both the hot pressed and the forged stock.
Balanced Resonator for Infrasonic Measurements of Young's Modulus and Damping in Flexure
Authors: Papadakis EP
Published: February 2009

A device called the Balanced Resonator is described and analyzed. It is the flexural analog of the torsion pendulum, and is useful for measuring Young's modulus and the logarithmic decrement in materials in flexure. While the device can be built for operation below 0.1 Hz and above 1000 Hz, the model reported in this paper operates in the vicinity of 1.0 Hz. Its useful features include rapid and convenient operation, frequency below the relaxations in most materials, low equivalent strain rates, moderate size for use in environmental chambers, and specimen configuration identical to ASTM tensile test bars. Experiments to demonstrate the utility of the Balanced Resonator are presented.
Quantitative Adhesion Tests of Vacuum Deposited Thin Films
Authors: Berendsohn O
Published: February 2009

An apparatus for performing quantitative adhesion tests of vacuum deposited thin films on a routine basis was developed by modification of a microhardness tester. The instrument employs a sapphire stylus which is drawn across the film surface until a critical load is established in one pass. This critical load is defined as the weight, in grams, at which the stylus completely removes the film in the contacted area. A number of critical loads for various metallic and dielectric coatings have been established and are being used to control the reliability of optical coatings. In addition, tests were conducted to determine the highest critical load, that is, the best adhesion possible for a given combination of materials and substrates. Typical values ranged from 25 to 100 g, the upper limit being determined by the cohesive strength of the substrate and the hardness and wear resistance of the stylus. The scribe method appears to be a substantial improvement on the “Scotch Tape” technique in that it yields quantitative adhesion data; and, thus, can be used to evaluate optimum deposition parameters, detect coatings of questionable quality, and give an early indication of coating deterioration.
A Microscopic Approach to the Microstructure of Paving Asphalts
Authors: Sontowski DP
Published: February 2009

Asphalts are colloidal solutions consisting of micelles (asphaltene plus adsorbed resins) of the dispersed phase and petrolenes (resins plus oils) of the continuous phase. Depending on the type of asphalt the micelles may flocculate to form a network of small or large structures measuring about 0.005 and 0.050 mm respectively. In the case of an oxidized roofing asphalt the microstructure observed measured about 0.150 mm. Thus, the microstructure can be conveniently observed with a suitable microscope utilizing high intensity reflected light. It is possible in this way to measure the size of individual micellar clusters and thus distinguish between various sol-gel and gel type asphalts.

The small microstructure is the result of good peptizing power of the resins and good solvency power of the petrolene fraction. The large microstructure on the other hand results from poor peptizing power of the resins and poor solvency power of petrolene phase.
Metallurgical Aspects of the Failure of the Point Pleasant Bridge
Authors: Bennett JA , Mindlin H
Published: February 2009

Examination of the fractured eyebar which caused the collapse of the bridge led to the conclusion that a stress-corrosion crack had penetrated to a depth of ⅛ in. during the 40 years that the bridge was in service. This flaw was sufficient to initiate fracture across the remainder of the 16 in.2 area of the lower limb of the eye due to the high local stress and the low fracture toughness of the steel.
Heat Treatment Effects on the Mechanical Properties in Ti-6A1-6V-2Sn
Authors: Hickey CF , Fopiano PJ
Published: February 2009

The effect of heat treatment on the mechanical properties (including fracture toughness) of the titanium alloy Ti-6Al-6V-2Sn has been investigated. Based upon a preliminary hardness survey of solution temperatures from 1300 to 1800°F, solution treatment temperatures of 1400, 1550, and 1700°F were selected for further aging heat treatments ranging from 700 to 1100°F for times up to 32 h. X-ray and electron microscopic observations and elastic modulus determinations were employed and correlated with the mechanical property data. A detailed discussion of the results and observations is contained in this paper.
Development of a Novel Specimen Geometry for Fatigue Testing of Fine Wire
Authors: Schmidt PA , Blair RR , Earthman JC
Published: February 2009

Despite a critical need to predict component life based on wire fatigue data, a survey of the literature indicates that no standard specimen exists for fatigue testing of fine wires. This article describes a plastically formed, precurved loop specimen developed to meet this need. The loop geometry localizes damage, permitting the use of in-situ, automated crack detection systems. The loop specimen is appropriate for wire diameters between a few hundred micrometres to a few millimetres, and for materials with a high elastic modulus. Material properties are presented for a cobalt-chromium-based alloy (Elgiloy) wire used as a practical example. Analytical and finite element stress analyses are presented which quantify the maximum stress at the loop apex. Fatigue life results using the present specimen are given for Elgiloy wire. Post-test SEM examinations are presented to show that fracture initiation takes place at the maximum stress location as predicted by the analyses. A fracture path and morphology characterization is also shown to be consistent with the anticipated stress regimes.
Deformation and Fatigue Behavior of Vanadium-Based Microalloyed Forging Steel in the As-Forged and Q&T Conditions
Authors: Yang L , Fatemi A
Published: February 2009

The use of microalloyed (MA) forging steels in the asforged condition can result in the elimination of the costly post-forging quenching and tempering (Q&T) processes. MA steels can therefore serve as economical alternatives to the traditional Q&T steels if equivalent mechanical properties can be obtained. In this study, monotonic and cyclic behaviors of a vanadium-based MA forging steel, one of the most commonly produced MA steels, were investigated under both the as-forged and Q&T conditions. The mechanical properties evaluated and compared include monotonic tensile behavior, cyclic deformation response, and low and high cycle fatigue resistance. Experimental results are presented and the differences in the behaviors under the two processing conditions are discussed.