bluuebunny/crossref_metadata_2025 huggingface dataset:
Results from a Round Robin on a Standard Method for Measurement of Fracture Toughness
Authors: Landes JD , Brown K
Published: May 2009

A paper round robin was conducted to evaluate the workability and reproducibility of a unified draft fracture toughness test standard titled “Standard Method for Measurement of Fracture Toughness.” The paper round robin consisted of 19 records from fracture toughness tests conducted separately from this round-robin exercise. These test records were given to the participants with the requirement that they use the draft standard to evaluate the fracture toughness values from the tests. The round robin was conducted between February 1991 and June 1992. Originally more than 30 organizations were invited to participate; however, only five finally responded with complete analyses of all of the test records. The five participants were all experienced in fracture testing and analyses. To subject the method to an evaluation by persons with less experience, some of the test records were analyzed by graduate students whose only experience with fracture testing and analyses was a course on fracture mechanics.

The round robin was conducted on Draft 10 of the proposed standard: “Standard Method for Measurement of Fracture Toughness” This paper contains a brief description of the draft test method, a discussion of the specimens and test records supplied, a brief summary of results, and a discussion of the changes made to the test method as a result of the round-robin exercise. All tests and analyses were conducted using English units; therefore, to accurately transmit the results, English rather than SI are used as the primary units of this report.
The Dynamic Behavior and Vibration Monitoring of Reinforced Concrete Beams
Authors: Wang Z , Man XTC , Finch RD , Jansen BH
Published: May 2009

The dynamic behavior of a reinforced concrete beam was studied theoretically and experimentally. A relationship between the resonance frequency of the beam and the applied bending moment was established. A frequency criterion corresponding to the crack control criterion in the ACI Building Code was developed. It was found that resonance frequencies and damping will change rapidly when cracks are initialized and growing. The resonance frequency shift could be as large as 20 to 25% of the original value, and the decay rate could change by a factor of 4. The applied bending moment not only determines the number and the size of cracks but also determines the crack opening or closing condition that affects both resonance frequency and damping. To accurately estimate the frequency and damping of a cracked-reinforced concrete beam, empirical formulas are proposed based on a small number of experiments. The technique has promise for global nondestructive evaluation of reinforced concrete structures such as highway bridges.
Experimental Justification for Proposed Changes to the Measurement of KIc Using ASTM E 399
Authors: Joyce JA
Published: May 2009

During the past five years considerable effort has been devoted to developing a fracture toughness measurement standard that combines the linear elastic stress intensity factor at the onset of crack extension, KIc, and the elastic-plastic fracture toughness measurement quantities, namely, JIc, the J resistance curve (J-R curve), and the corresponding crack tip opening displacement resistance curve (CTOD-R curve). The objective of this effort was to allow the engineer to start with one specimen geometry, conduct a specified test, develop either a KQ or a JQ−R curve, and then, after application of the relevant size requirements, obtain a valid fracture toughness result. At present, different specimens are required by E 399 and E 1737 (the combination and replacement of E 813 and E 1152), and if the engineer uses the E 399 specimen geometry and test procedure and subsequently finds that the measured KQ fails the E 399 size requirements, new specimens must be machined and tested according to E 1737 to obtain valid fracture toughness measurements.

This paper describes experimental tests that have been conducted in parallel with the development of the new ASTM Standard E 1820-97, a combined fracture toughness test standard that is intended to address this problem. These experimental results show that the standard J integral specimen, incorporating load line crack mouth opening displacement measurements and side grooves, can be used to obtain KIc as presently defined by ASTM E 399. The use of larger a∕W ranges is also supported by these results as long as the basic size requirements of E 399 are met and applied to both the specimen crack length and remaining ligament as well as to the specimen gross thickness.
Role of Filter Paper Separators on the Response of Clays Under Long-Duration Sustained Loading
Authors: Robinson RG , Allam MM
Published: May 2009

In a one-dimensional consolidation test, a sustained load duration in excess of 104 min is rarely used for evaluation of the coefficient of secondary compression even for very plastic clays. However, there are instances in the literature where load durations have exceeded 105 min. The clogging of porous stones by migration of soil fines is conventionally prevented by interposing filter paper separators between the porous stones and the soil specimen. The present study examines the effect of filter paper separators on the secondary compression and swelling characteristics of a bentonite-sand mixture. In longterm volume change tests, use of filter paper separators results in increased deformation when the soil is undergoing drained creep in consolidation tests. When the soil undergoes swelling over a long period of time, some collapse occurs due to the decay of the filter paper separators. The observations of a long-duration drained creep test on this soil are used to explain the reported secondary compression behavior of some natural soils. The results of the study bring out the need to develop nondegradable separators for long-duration tests to protect porous stones from clogging with soil fines.
Thermal Diagnostic Method for Vehicle Brakes
Authors: Segal L
Published: May 2009

Theoretical and experimental validation is provided for thermal diagnosis of vehicle brakes in the example of a wheeled tractor. The diagnostic parameter adopted is the rate of temperature increase of the brake under steady-state conditions. The functional relationship between it and the structural parameter (the braking moment) is determined.
A Computer Program to Aid in Fatigue Precracking of Fracture Toughness Test Specimens
Authors: Sriharsha HK , Anantharaman S , Chatterjee S , Pandey RK
Published: May 2009

Fatigue precracking prior to fracture toughness and fatigue tests ensures a sharp crack ahead of the notch tip. The precracking procedure is outlined in ASTM Standards E 399-78a (Standard Test Method for Plane-Strain Fracture Toughness of Metallic Materials). E813-89 (Standard Test Method for JIC, A Measure of Fracture Toughness), and E-1152-87 (Standard Test Method for Determining J-R Curves). This paper describes an interactive computer program that accepts material properties and specimen dimensions as program input. The program output when plotted graphically suggests an easy and practical precracking procedure adhering to the standards mentioned above. The program is useful in the absence of a computer-controlled testing facility. The program listout is given in the Appendix.
Evaluation of Wear Resistance of Snow Plow Blade Cutting Edges Using the Scratch Test Method
Authors: Wei Y , Nixon WA , Shi Z
Published: May 2009

The scratch test method was used to evaluate the wear resistance of snow plow blade cutting edges. A testing apparatus peculiar to the in situ scratch test of cutting edges was developed. Experimental results indicated that the scratch hardness correlated better to the wear resistance of cutting edges than did the indentation hardness.
Vickers Hardness Indentations Measured with Atomic Force Microscopy
Authors: Jensen CP , Jorgensen JF , Garnaes J , Picotto GB , Gori G
Published: May 2009

Vickers hardness indentations on a steel gage block (-900 HV) with diagonals between 3.4 and 44 µm have been measured with a calibrated atomic force microscope (AFM) and with an opticalbased method. From the AFM images the diagonals were measured from hard copies of diagonal profiles and automatically by image analysis. The combined standard uncertainty for the 3.4-µm diagonals was 10% for the optical-based and only 2.4% for the profile-based measurements (68% confidence level). Indentations with diagonals between 10 and 44 µm had concave shapes, in contrast to the 3.4-µm indentations. We show that optical-based measurements were not made at the level of the background plane, but higher on the indentation ridges.
A Neural-Based Analog IC Parametric Fault Diagnostic System with Discriminant Simulation Sampling
Authors: Wu A
Published: May 2009

This article presents experimental results that show feedforward neural networks are well suited for analog IC parametric fault diagnosis. It describes a discriminant sampling method for analog IC parametric faults simulation for a neural-based diagnostic system to reduce the computational overhead of the neural network training phase. Analog circuit fault simulation has not achieved the same degree of success as its digital counterpart owing to the difficulty in modeling the more complex analog behavior. Analog circuit fault simulation does rely on time-consuming circuit simulations on a large number of sampled points subject to various process deviations to emulate the actual faulty conditions. The proposed algorithm uses an effective importance sampling strategy to capture the parametric acceptance boundaries of the circuit under test. It makes use of circuit simulations effectively to relate each circuit performance to the process disturbances and to establish response functions that are accurate at the transition boundaries of the acceptance region. With the proposed approach, simulation samples can be generated for fault simulations mostly at the boundaries of the acceptance region to institute the discriminant functions for parametric faults testing using a neural network approach. The proposed algorithm is more computationally effective when compared to the Monte Carlo method.
An Alternative Procedure for the Analysis of Data from the Cup Method Measurements for Determination of Water Vapor Transmission Properties
Authors: Kumaran MK
Published: May 2009

The cup methods are used extensively to determine the water vapor transport characteristics of building materials. The dry cup method and the wet cup method prescribe two standardized procedures for this purpose. The dry cup method gives the results as an average value of the property at a mean relative humidity of 25% and the wet cup at 75%. This information is inadequate for detailed hygrothermal analysis of building components. The complete dependence of water vapor permeability on relative humidity is required by most of the current computer models used for hygrothermal analysis. This paper presents an extension of the cup methods in which a series of dry cup and another series of wet cup measurements are suggested at varying relative-humidity levels outside the cup. Also, a detailed procedure for the data analyses to define the dependence of vapor permeability on relative humidity is presented. The methodology is applied successfully to three materials: perlite insulation board, calcium silicate insulation board, and plywood sheathing.
A Testing Device for the Mechanical Characterization of Wood Beams or Plates Under Bending Compression
Authors: Mussot-Hoinard G , Ferron G
Published: May 2009

A bending-compression device has been designed with the help of the ABAQUS/Standard finite element code for studying the mechanical behavior of structural elements under complex loading. A description of the device and its principle are presented. Samples are instrumented with the aim of a better comprehension of the damage mechanisms up to rupture. Current strain on the middle of the upper and lower faces and acoustic emission (AE) signals is collected. A coupled analysis of the mechanical and physical responses are made related to visual observations. Results are illustrated in the case of spruce beams loaded under bending up to rupture with the bending moment along the direction perpendicular to the annual rings.
Evaluation of Three Methodologies for Testing Disposable ENT Endoscope Sheaths as Viral Barriers
Authors: Lytle CD , Clavet CR , Chaput MP , Varney GW , To TM , Carey RF , Baker KH
Published: May 2009

Three methods to determine the barrier function of ENT endoscope sheaths were evaluated: (1) the air deflation test, a candidate quality assurance test, compared differences in pressure between a test sheath and an intact one; (2) a virus barrier test challenged with bacteriophage ΦX174 outside the sheath, with barrier penetration determined by rinsing inside and assaying for penetrated virus; (3) another virus barrier test challenged from inside, with virus penetration determined by assaying a collection/submersion solution. Sheaths with laser-drilled holes or tears generated by acupuncture needles were tested. Five-µm holes and larger were detected by air deflation or inside virus challenge. Outside virus challenge could reliably detect only 30-µm holes. Tears of 35-µm length were detected by inside virus challenge, while all three tests detected 85-µm tears. In addition, air bubbles during submersion detected and located 5-µm holes and larger, suggesting another quality assurance test.
Effect of Construction Adhesive and Joist Variability on the Deflection Behavior of Commercial Wood Floors
Authors: Pellicane PJ , Robinson G
Published: May 2009

A total of 19 440 virtual structural floors of a geometry and material configuration consistent with those used in commercial construction (commercial floors) throughout North America was numerically analyzed to determine deflection characteristics under a constant uniformly distributed load of 95 lbf/ft2 (4.55 kPa). The intent of these analyses was to determine the effect of joist variability on the deflection behavior of floors with and without elastomeric construction adhesive (ECA) between sheathing and joists. The joist property (modulus of elasticity, MOE) was allowed to vary in a systematic fashion between 1250 (8.62) and 3250 (22.4) ksi (MPa) in increments of 250 ksi (1.72 MPa). In addition, the variability of the joists (at each value of MOE) varied between coefficient of variation (COV) values of 0.025 to 0.150 in increments of 0.025. One hundred eighty floors were evaluated with and without ECAs at each mean MOE value and at each COV value for the joists. All other sheathing and connector properties remained constant.

The results indicated that the contribution of the ECA to reducing floor deflection under uniformly distributed loads was dependent in large part on the mean stiffness of the floor joists and to a much lesser extent on the COV of the joists. For joists of lower stiffness, the contribution of ECA had a more pronounced effect on mitigating the floor deflection level. Reductions of nearly 10% were realized when the mean joist MOE was 1250 ksi. For floors made with stiffer joists (mean MOE 4 3250 ksi), floor deflections were reduced by only about 5.5% when adhesive was used. The presence of ECA between joist and sheathing did not have much effect on reducing the variability of floor deflection behavior.
An H2-Optimal Control of Random Loading for a Laboratory Fatigue Test
Authors: Ming L , Bing-Han X , You-Sheng W
Published: May 2009

The authors have proposed an H2-optimal control method of random loading for a fatigue test. The optimal prefilter or optimal controller has been realized, and its system function or frequency response function was derived. The control method was verified by a test, and its use was presented.
Crack-Arrest Testing of Irradiated Nuclear Reactor Pressure Vessel Steels at the Oak Ridge National Laboratory
Authors: Iskander SK , Milella PP , Pini A , Manneschmidt ET
Published: May 2009

Crack-arrest testing of nuclear pressure vessel steels has been conducted at Oak Ridge National Laboratory for many years. Four methods have been used to initiate fast-running cracks in crackarrest specimens: (1) the deposition of a brittle weld bead using hardfacing weld electrodes, (2) water quenching a chevron crack tip, (3) quenching the crack tip by discharging a large current into the crack tip region, and (4) the use of duplex specimens. A problem often encountered with Methods 1 and 4 is the control of the width of the heat-affected zone (HAZ). The HAZ is generally tough and can arrest crack propagation before it has run into the test section. Irradiated crack-arrest specimens were prepared using Methods 1, 3, and 4. Method 1 was the most successful, while Method 4 was the least successful. This paper will discuss some of the reasons for the success, or lack of, as well as the results of testing both a high-copper weldment and a low-copper forging in terms of the shift and shape of the Ka toughness curve compared to the Charpy V-notch shift. The present ASTM Test Method for Determining Plane-Strain Crack-Arrest Fracture Toughness, KIa, of Ferritic Steels (E 1221-88) validity criteria will also be discussed in light of the results.
On the Uncertainties Involved in Quantifying the Fracture Toughness of Al-Li-X Alloys
Authors: McKeighan PC , Hillberry BM
Published: May 2009

The fracture behavior of an extruded Al-2.6Li-0.09Zr alloy in a near peak-aged and over-aged condition was found to be primarily intergranular with formation of non-Mode I, crack-divider delaminations at the crack tip especially in the over-aged temper. This complex, irregular fracture mode results in behavior that cannot be accurately measured using the conventional J- and K-based toughness parameters and testing methods. Other observed fracture characteristics that force reassessment of the traditional testing methodologies include crack length variations, mixed mode fracture from crack deflection, and apparent plasticity. The observed crack length variations through the specimen thickness led to 4 to 8% uncertainty in the K-curve for the specimens used. Furthermore, crack deflection corrections lead to an average 4 to 7% and maximum 15 to 18% apparent toughness increase for the material. The alloy exhibited nonlinear load-displacement behavior during fracture that could be corrected by using a plastic zone size modification. The analyses outlined provide insight into the roles the various mechanisms play in the fracture process of this alloy. However, the conventional toughness measures were inadequate in treating the observed fracture behavior.
R-Curve Generation and CTOD Evaluation Considering Maximum Crack Growth Size and Parabolic Crack Front
Authors: Bhattacharya S , Kumar AN
Published: May 2009

The standard methods of estimating the average size of the slow crack growth region as described in BS 5762 (Crack Opening Displacement (COD)) and ASTM E 1290 (Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement) are cumbersome, painstaking, time consuming, and dependent on several factors; e.g., section thickness, the nature of crack front profile, and the number of measurements. Often errors are introduced in determining the average crack size which in turn affect the determination of critical CTOD value.

However, several merits are associated with the use of maximum crack size. A theoretical relationship is established between the two physical quantities by assuming a parabolic nature of the slow crack growth front profile, which is supported by experimental data points. In situations of large crack growth, the crack profile tends to change from a parabolic to a semicircular crack front. A new approach is proposed to make use of the maximum crack size to generate R curves that can be extended to yield critical CTOD values. The nonlinear regression analysis of the CTOD-maximum crack size R curve yields critical CTOD values in agreement with the values that may be obtained by BS 5762. However, the linearly regressed and extrapolated critical CTOD values are found to be highly conservative. Alternatively, the average crack size may be obtained theoretically by using maximum crack size data to determine CTOD values following BS 5762.
Crack Length and J-Integral Expressions for Specimens Loaded in Tension
Authors: Faucher B
Published: May 2009

Equations are developed to calculate the J-integral from the area under the load-displacement curve obtained with center-cracked M(T) and double-edge-notched DE(T) tension specimens. Analytical expressions are also derived to calculate the crack length from unloading compliance.
A Computer Method of Analysis for Tire Wear Characterization, Identification, and Classification
Authors: Changizi K
Published: May 2009

A tire's rib profile before and after use can be determined by using two sets of measurements. These measurements are the tire runout values taken along the ribs before and after use. Superimposing these values over a circle with a predetermined constant radius that depends on the overall unloaded diameter of the tire as well as the maximum peak-to-peak runout value of the rib will result in the tire's rib profile. The difference of areas bounded between the rib's profile and the specified circle, before and after use, is a quantitative measure of tire wear along the rib. Therefore, it is the primary objective of this paper to outline a computer method of analysis, not only to generate the tire's rib profile before and after use, but also to provide a quantitative measure of rubber loss around the circumference of each tire rib. The significance of generating the profile is the ability to observe and locate the highest and lowest points of the tire along the rib and to inspect a tire for defects. This can be especially important for the tire manufacturers at their line of production. Among other important characteristics of this proposed method is the potential for predicting the wear nature of a tire rib, after use, by quantifying the loss of the rubber along the rib and by the process of decomposing each rib's profile into the sum of sinusoids with appropriate amplitudes and phase angles. This process of decomposition, which is commonly known as Fourier Analysis, can identify the harmonics with highest contributions to the shape of the profile. Harmonics with highest contributions play an important role in shaping the profile. Two tires with similar or close harmonic contents in their rib's profile, after use, can be classified as tires with identical wear pattern.
Physiologic Challenges Induced by Participation in Ice Hockey—Implications for Training
Authors: Green HJ
Published: May 2009

Training programs for ice hockey players have two fundamental objectives; namely, to optimize performance and to minimize the risk of injury. The design of efficient and successful programs to meet these purposes depends on a careful analysis of the physiological demands of the game and the environment in which it is played. Moreover, if the program is to meet individual needs, the physical and physiological status of the player must be considered. Ice hockey is a demanding sport that involves the recruitment of essentially all of the skeletal muscles of the body in order to perform the diverse skills of the game. These skills are performed over various ranges of movement, at various velocities and loads, and usually involve several large muscles acting synergistically. Moreover the extended nature of the game, performed over three periods, results in numerous repetitions of each task. Collectively, the repeated performance of these tasks impose extreme demands on respiratory, cardiovascular, neural, muscular, metabolic, and thermoregulatory systems of the body. The physiological demands may be further exaggerated given the protective equipment that is worn and the fact that abnormally high temperatures and humidities may be present. Proper preparation can only be realized by exposing the participant to progressive routines designed to systematically challenge each of the physiologic systems in a manner appropriate to game conditions.
Practical Aspects of Dynamic Verification of Extensometers: Part I—The Concepts
Authors: Albright FJ , Annala J
Published: May 2009

Material property studies frequently require the measurement of load and strain. Accurate measurement of both parameters is essential. Methods for accurate static calibration and verification of load transducers and extensometers are well established. More recently, standard practices have been developed for the dynamic calibration of load transducers. Still in its infancy is a standard method for dynamic verification of extensometers.

Dynamic verification introduces a wide range of new issues. These encompass not only the transducer but also the conditioning electronics and actual test machine. Static calibration permits the “elimination” of nearly all dynamics, whereas dynamic verification must be done in the presence of these dynamic effects. This paper outlines the various concepts that need to be understood when performing the dynamic verification of an extensometer. Problems related to computer aided verification are emphasized, issues of aliasing and resolution in particular.
Statics and Strength of Materials, Second Edition
Authors: Shehata IH
Published: May 2009

The second edition of this book, which comes twelve years after the release of the first, mainly targets engineering technology and non-engineering university students with no calculus requirements, as the author states. However, the book may also serve as a reference for courses in materials and materials testing as well as machine and structural design. Two new chapters have been included in this edition: Concurrent Forces in Space (under the Statics branch) and Bolted, Riveted, and Welded Structural Connections (under the Strength of Materials branch). In addition to many changes and improvements throughout all the chapters of the book, this edition contains three new sections: Power Transmission, Flange Couplings (under the chapter named Shear Stresses and Strains; Torsion), and Design of Beams for Strength (under the chapter named Bending and Shearing Stresses in Beams). However, the new chapter Concurrent Forces in Space seems to be very short (it may be described as the five-example and fourteen-problem chapter) and needs to be critically examined.
Fatigue Crack Propagation in a Specimen with a Complicated Cross-Section; Characterization of the Stress Intensity Factor
Authors: Makabe C , Kaneshiro H , Yara H
Published: May 2009

In order to predict the fatigue life of machine equipment, the fatigue crack propagation law has up to now been investigated using specimens with a simple cross-section shape. In this study, a specimen with three grooves cut in the loading direction was used to clarify crack propagation and crack closure behavior at points of discontinuous change in thickness. It was found that the crack propagation curve showed a complicated variation in the vicinity of the grooves and that the variation of crack closure behavior correlated well with it. The stress intensity factor was evaluated using the calibration curve between the crack propagation rate and the effective stress intensity factor range obtained from a similar smooth specimen. Results showed that the stress intensity factor of the grooved specimen was higher in front of the first groove and lower behind it, compared to the smooth specimen. As the crack crossed the first groove, the crack propagation rate exhibited a local maximum as a function of the maximum value of stress intensity factor.
The Use of Fatigue Specimens Precracked in Compression for Measuring Threshold Values and Crack Growth
Authors: Pippan R , Plöchl L , Klanner F , Stüwe HP
Published: May 2009

Precracks generated in purely compressive cycles permit a determination of threshold values ΔKth and crack growth curves with increasing load amplitude only. They also permit to measure the effective threshold ΔKeff th and the dependence of ΔKth on crack length. The production of such precracks is also discussed.
Development of an Improved Compression Specimen Geometry for Unreinforced Polymers
Authors: Odom EM , Adams DF
Published: May 2009

One of the recommended compression specimen geometries for plastics in ASTM D 695, Test Method for Compressive Properties of Rigid Plastics, is a straight-sided cylinder or prism. This end-loaded specimen tends to barrel at high strains. Additionally, if modulus is desired, the standard suggests that the specimen have extra length to avoid end constraints. Therefore, compression specimens for modulus can fail at a different stress level than compression specimens for strength. To overcome these problems, a compression specimen with a gage section of reduced area which is end-loaded but side supported was developed. Additional experimental observations of the thermosetting polymer of interest included a nonlinear compressive stress-compressive strain response which required a parabolic constitutive relationship to model, an observation of a significant anelastic material response, and a material response termed anelastic buckling. These observations of material behavior had not previously been observed.
Back-Face Strain Compliance and Electrical-Potential Crack Length Calibrations for the Disk-Shaped Compact-Tension DC(T) Specimen
Authors: Gilbert CJ , McNaney JM , Dauskardt RH , Ritchie RO
Published: May 2009

Back-face strain compliance and electrical-potential crack length calibrations have been experimentally determined for the disk-shaped compact-tension DC(T) specimen. Finite-element modeling was used to ascertain the back-face strain distribution at several crack lengths to determine the significance of inconsistent gage placement. The numerical solutions demonstrated good agreement with experiment, especially at smaller crack lengths when the back-face strain gradients are minimal. It is concluded that precise gage placement is only critical when the crack tip closely approaches the back of the test specimen.
Constant Temperature-Compensated Strain Rate Testing of Aluminum
Authors: Sample VM , Field DP
Published: May 2009

Temperature and strain rate have long been identified as the external variables dictating material response during deformation. The Zener-Hollomon parameter, Z, is a temperature-compensated strain rate defining the interrelationship between the two variables. Investigation of the constitutive response of a material requires well-defined testing conditions in order to properly identify material behavior. Mechanical testing at constant Z values offers the advantage of using well-defined deformation conditions when isothermal control cannot be maintained during deformation. To perform such tests real time feedback control of the strain rate is required. In addition, at high strain rates where deformation heating becomes significant, thermocouple response is not rapid enough to provide feedback signal adequate for control of the test. Under these circumstances it is necessary to predict deformation heating of the specimen as a function of the test parameters and control the strain rate based upon the estimated specimen temperature. Results of constant Z tests are presented showing the capabilities of the control system. Deformation heating is accounted for by a simple equation assuming a near adiabatic process which predicts the dissipation of heat through the surrounding environment. An application of the constant Z test procedure for modeling material behavior is briefly discussed. The ability to perform deformation experiments at constant Z values offers significant advantages in gaining an understanding of the constitutive response of materials.
Local Strain in Corrugated Pipe: Experimental Measurements to Test a Numerical Model
Authors: Moore ID
Published: May 2009

Measurements of local strain in corrugated steel and high-density polyethylene (HDPE) pipe are used to test the effectiveness of a three-dimensional finite element analysis. Measurements were made at the horizontal diameter for the pipes subjected to parallel plate loading, a load condition that produces significant strain gradients around the pipe as well as through the corrugation. The test values are used to evaluate the performance of elastic analysis for both steel and polyethylene pipes, as well as viscoelastic analysis used for the polyethylene pipe alone. It is demonstrated that the theoretical model generally yields estimates of local strain within 5 to 15% of the measured values. The viscoelastic predictions of local strain through a load-unload cycle on the HDPE pipe were very good. The load-deflection response of HDPE is predicted well for monotonic loading, but improvements in the viscoelastic model for HDPE appear necessary to improve predictions through a full load unload cycle.
Determining Asphalt Concrete Properties via the Impact Resonant Method
Authors: Whitmoyer SL , Kim YR
Published: May 2009

Various publications have demonstrated that the results from the resilient modulus test (see ASTM D 4123, Method for Indirect Tension Test for Resilient Modulus of Bituminous Mixtures) display a wide range of variability. Considering this, an alternate testing method that produced more consistent results with a simpler test setup was pursued. A standardized vibrational test procedure for Portland cement concrete (ASTM C 215, Test Method for Fundamental Transverse, Longitudinal, and Torsional Frequencies of Concrete Specimens) was modified to measure the material properties of asphalt concrete. The impact resonant method provided three separate, independent tests, two measuring the elastic modulus and one the shear modulus. Poisson's ratio was obtained by comparing moduli results. Unlike the semi-nondestructive nature of the resilient modulus test, the impact resonant method was a true non-destructive test. The method also allowed for a possible laboratory link to nondestructive analysis of in-situ pavement. Experimental test results demonstrated that the impact resonant method provided precise and reproducible results. Further experiments revealed that the impact resonant method could detect different magnitudes of microcrack healing.
Testing Techniques for Measurement of Bulk Modulus
Authors: Fishman KL , Machmer D
Published: May 2009

The objective of this study was to examine prospective tests for determining the bulk modulus of elastomers used in the construction of elastomeric bearings. Because elastomeric materials are nearly incompressible, relatively slight volume changes are experienced during isotropic compression, sizably governing the accuracy of test measurements. For this reason major topics of interest are equipment calibration, test repeatability, and error accountability.

Test methods explored included use of a deformation jacket, a fluid displacement volume change measurement device, and load ram displacement for measurement of volume change. For verification of test methods specimens of Adeprene were tested.

Results from all test methods were found to be suitably, but not equally, repeatable. Considering ease of operation, and acceptability of errors, the load ram method is found to be superior compared to other methods investigated.
Development and Validation of a Standard Test Method for Sequential Batch Extraction of Waste with Acidic Extraction Fluid
Authors: Sorini SS
Published: May 2009

A project was conducted to develop and validate a sequential batch extraction method using a dilute acid solution as the extraction fluid. The method was developed by ASTM Task Group D-34.02.01 on Waste Leaching Techniques, and calls for the pH of the extraction fluid to reflect the pH of acidic precipitation in the geographic region where the material being tested is to be disposed. A collaborative study of the method was conducted to determine the multiple-laboratory and single-operator precision of the extraction procedure when applied to two different waste materials using two different pH values. A general statement on the precision of the method that covers all wastes, analytical parameters, and extraction fluid pH values cannot be made because the data generated in the collaborative study are specific to the test materials, extraction fluid pH values, and elements of interest in this study. However, the data generated in the study provide information on the variability that can be expected between test results when the method is used by one or more laboratories. This information will help potential users assess the usefulness of the method in their proposed applications.
Ensuring Software Reliability
Authors: Megargle R
Published: May 2009

Anyone who has worked on a medium to complex programming project, one that requires more than a few days to complete, knows how difficult and time-consuming it is to test software and find errors. It often requires several times more effort to locate and fix bugs than to design and write the program. At first we blame ourselves, thinking it is our own inadequacies that cause us to make so many mistakes. We soon learn that almost everyone has the same experiences. These realizations have led to studies of the process of developing software, undertaken to find out if there are ways to contain the errors or facilitate their locations and corrections. The current status of this field of study is reviewed in this book, which is Volume 38 of Dekker's extensive series on “Quality and Reliability” edited by E. G. Schilling.
Ultraclean Technology Handbook, Volume 1, Ultrapure Water
Authors: Lerman S
Published: May 2009

This work is the first in what appears to be a comprehensive treatise on ultraclean technology in the semiconductor industry and other industries that require ultraclean technology. As the title indicates, this is a handbook, or more accurately, an in-depth encyclopedic treatment of the subject. Its audience includes scientists, engineers, and others involved with virtually any aspect of ultrapure water, and, although the author's target is the semiconductor industry, this volume is valuable to anyone working with ultrapure water.
Fatigue Testing of High-density Polyethylene and Polycarbonate with Crack Length Measurement Using Image Processing Techniques
Authors: Riemslag AC
Published: May 2009

A new automated method of measuring fatigue cracks in polymers is discussed. The new method is based on a video signal of the crack which is analyzed with “image processing” techniques. With this technique the crack length is measured every 20 s during a fatigue test. The accuracy of one single measurement is about 0.05 mm, but this can be increased by averaging a large number of measurements. The applied automated data collection and subsequent data processing is discussed in relation to the recommendations given in ASTM E 647, Test Method for Measurement of Fatigue Crack Growth Rates.

The use of the new technique is illustrated on the basis of fatigue tests performed on transparent polycarbonate (PC) and nontransparent polyethylene (PE). The fatigue behavior of PE and PC is briefly discussed.
The Influence of Testing Methodology on the Fatigue Crack Propagation Behavior of Cellulose Esters
Authors: Pecorini TJ , Moskala EJ
Published: May 2009

In the fatigue crack propagation behavior of cellulose esters, a crazing mechanism controls growth at low stress intensity (ΔK) levels while a plane-strain-shear yielding mechanism becomes dominant at higher ΔK values. The growth rate associated with the transition between these two mechanisms has been found to be a function of the material's yield strength. Most recent data have shown that the onset of this transition is also related to the test methodology. Constant-load-amplitude, K-increasing tests produce the most conservative (highest fatigue rate) values for the transition, whereas with decreasing stress intensity tests, the transition occurs at much lower growth rate values. It is important to note, however, that test methodology does not affect the relation between crack growth rate and ΔK when growth is dominated by only a single mechanism.
An Evaluation of Several Techniques for Measuring Air-void Content in Asphalt Concrete Specimens
Authors: Harvey J , Mills T , Scheffy C , Sousa J , Monismith CL
Published: May 2009

Precise and accurate measurement of air-void content is critical to the evaluation of asphalt-aggregate mix specimens taken in the field or compacted in the laboratory. It is an integral part of the performance-based testing and analysis methods developed by the Strategic Highway Research Program Contract A-003A (SHRP A-003A). Standard methods for drying specimens after coring and/or cutting from a larger compacted mass, and for measuring bulk specific gravity present problems for testing of the same specimen using equipment developed by SHRP A-003A, or whenever the specimen must be fixed to the testing equipment by means of an adhesive.

This paper presents a comparison of the standard methods of air-void content measurement, measurement of bulk specific gravity using unsealed specimens and using specimen sealed with paraffin wax (ASTM D 1188, Test Method for Bulk Specific Gravity and Density of Compacted Bituminous Mixtures Using Paraffin-Coated Specimens), with three alternative methods for sealing the specimen: dusting with zinc stearate powder, wrapping with a waxy elastic paper called Parafilm™ (American National Can), and covering with a rubber membrane. The results indicate that each of the methods produces different measured air-void contents. The waxy elastic paper results were closest to those obtained from specimens sealed with paraffin, and it is suggested that this is a suitable alternative to paraffin wax when the specimens have smooth (cut/cored) surfaces and are to be tested for performance afterward.

The use of an air gun to dry specimens after coring and/or cutting was compared with the standard oven-drying method (ASTM D 2728, Practice for Paving Uses and Application Temperatures for Road Tars). It was found that the use of a 210 kPa (30 psi) air gun produced similar results to those found with the standard method and was nondestructive, thus allowing further testing of the specimen.
Mechanical Study of a Hypoeutectoid Steel Weld
Authors: Martínez JA , Kugler HP , Merino S , Drude H , Criado AJ
Published: May 2009

A comparative study was made of the mechanical behavior of the different zones in a welded joint of hypoeutectoid steel, using the uniaxial tension test supported by other conventional techniques. Applying the optoelectronic method to recording and analyzing the results of a tension test gives the distribution of the deformations produced in a test-piece and shows the plastic properties of each zone in one sole experiment.
Comparative Studies of Yarn and Fabric Friction
Authors: Ajayi JO , Elder HM
Published: May 2009

A comparison of the magnitudes of yarn-to-yarn and fabric-to-fabric friction is made. It is shown that yarn friction measured on a capstan (cylindrical) surface is significantly greater than that measured on a flat surface. The greater magnitude of the coefficient of friction in a capstan assembly is ascribed to the effects of experimental variables such as capstan radius, angle of lap, and input tension. The coefficient of friction of fabrics is also shown to be greater than that of their component yarns. Yarns with higher frictional properties yield fabrics whose frictional properties are also higher.
Summary on the Role and Analysis of Wear in Failures
Authors: Wood FW
Published: May 2009

An overview of the meaning of wear, how it occurs, its involvement in failures, and how it can be detected and evaluated is presented. Relevant definitions, surface characteristics, detrimental consequences, and techniques for investigation and analysis are reviewed. The intentions are to provide a basis for interrelating the case histories presented at the Symposium on Wear-Related Failure Analyses, and, together with the more specific case histories, to heighten the realization of the role that wear plays in many failures.
Wear Analysis of Björk Shiley Delrin Tilting Disc Heart Valves
Authors: Milligan HL , Johnson BM , Engel PA
Published: May 2009

Prosthetic heart valves must open and close 40 million cycles annually, year in and year out, in a biochemically active and corrosive medium and without benefit of periodic maintenance. Examination of explanted Björk-Shiley Delrin Heart Valves revealed that some valves developed wear grooves in the Delrin occluder disc from contact with the inlet strut. With Delrin Heart Valve implant durations reaching 20 or more years, studies were initiated to fully analyze the wear of explanted valves.

Delrin discs from 15 explanted valves with implant durations of up to 20 years (800 million cycles of operation) were dimensionally inspected; the wear features and profiles measured by stylus profilometer and optical comparator; wear surfaces mapped by Moiré shadow interferometry; and the surfaces examined by scanning electron microscope. Pulsatile flow heart valve simulator studies were conducted to determine valve disc impact velocity and impulsive force-time characteristics. Material tests were conducted on circa 1970 Delrin coupons to determine the wear-related physical properties of the Delrin disc. These investigations cast light upon the wear behavior of Delrin occluder discs, and hence their effects upon valve performance and valve life could be evaluated.

The wear phenomenon as seen on clinically explanted valves can be attributed to percussive impact wear concepts. The wear depth from this mechanism is shown to be a logarithmic function with respect to cycles and time. The amount of wear observed on the periphery of the explanted Delrin discs returned to date suggests that clinically significant increases in valve regurgitation in implanted valves has not likely occurred. Disc retention safety margin appears not to be substantially affected. In conclusion, wear of the disc in the 15 Björk-Shiley Delrin Heart Valves in this study does not appear to be a factor affecting valve life.
Wear-Related Fatigue in a Wire Rope Failure
Authors: Schrems KK
Published: May 2009

The fatigue failure of a nonrotating wire rope used on a skip hoist in an underground mine has been studied as part of the ongoing research by the U.S. Bureau of Mines into haulage and materials handling hazards in mines. Correlation of individual wire failures within two segments of the failed rope were used to gain an understanding of the progression of degradation leading to rope failure. Wire failures occurred predominantly at locations of wear between adjacent strands. These interstrand wear sites are identifiable by a large reduction in diameter; however, reduction in area is not responsible for the location of failure. Fractography revealed crack initiation sites to be located opposite the characteristic wear site or at other less noticeable wear sites. The primary failure mechanism of individual wires within the rope is believed to be a function of contact stress at the interstrand wear sites. Axially loading and unloading the rope produces high compressive stresses at the contact sites, which in turn produce large alternating tensile stresses on the opposite side of the wire. This mechanism has been termed “contact stress-accelerated fatigue.” This mechanism and the affiliated wear pattern both are consequences of interstrand contact.
Handbook of Adhesive Bonded Structural Repair
Authors: Bajere PA
Published: May 2009

This handbook is written by two material and manufacturing process engineers with over 60 years of combined experience in government. The purpose of the book is to: (1) provide a standard method for repairing adhesive bonded and composite laminate structures; (2) identify suitable materials and equipment for making satisfactory repairs, and (3) discuss methods by which structures may be inspected both before and after repair. It is designed as a reference manual. The intended audience includes anyone who needs to find recommended information on materials or procedures for adhesive bonded structural repair that meets applicable safety and health standards.