bluuebunny/crossref_metadata_2025 huggingface dataset:
Comparison of ISO/FDA and ASTM Condom Water Leak Test Methods
Authors: Kerr LN , Boivin WS , Hamilton SL , Mailhot SA , O'Malley LG , Boyd SM , Pierdominici VJB , Bushar HF
Published: February 2009

This research compares the ISO/FDA and ASTM water leak test methods for detecting defects in latex and synthetic condoms. Detection rates of standardized defects are quantified for four condom materials. The overall detection rate of the ISO/FDA method (53.4%) averages 12.3% higher than the ASTM method (41.1%) and is higher for each of the four condom materials. Detection rates for both test methods vary significantly by condom material. The ISO/FDA method is effective in detecting 30 μm laser defects in polyurethane and latex condoms (79.9 and 69.7%, respectively), but is not very effective in baggy and high elongation condoms (24.4 and 39.7%). Due to the limited number of condoms tested, only four combinations of material, defect type, and hole location showed statistically significant differences in detection rates for ISO/FDA versus ASTM methods. Data produced by this research may help harmonize the ASTM and ISO/FDA water leak test methods.
Characterization and Creation of Defects in Condoms
Authors: Kerr LN , Chaput MP , Boyd SM , Galevi EA , Millward PA
Published: February 2009

Defects in condoms were examined, then characterized and compared with defects introduced using various techniques. Eighty-five percent of the condom defects examined were classified as either a hole (void in material) or a slit (puncture). Laser drilling and puncturing with a 160 μm diameter acupuncture needle artificially introduced similar types of defects. Microscopic examination of the created defects, before and after FDA water leak testing, showed that this test method does not increase the size of preexisting microscopic defects. Examination also showed that these creation techniques generated reproducible defects within a condom type, with the size of acupuncture needle defects varying less than laser drilled defects. Results of water leak testing showed that the leakage characteristics of defects are affected by the material type, the condom shape and size, the type of defect and the defect size, and the presence of lubricant.
Empirical Models Depicting Grain Angle Effects on Load-Embedment Response of Dowel-Type Fasteners in Wood
Authors: Li Y , Chui YH
Published: February 2009

Predicting the moment-rotation response of a multifastener timber joint requires the use of empirical models that describe adequately the influence of load-to-grain angle on embedment response of wood under a dowel fastener. This paper presents two models. The first model describes the relationship between load, embedment, and load-to-grain angle, and can be used for predicting moment-rotation response of a multifastener joint. The second model relates the ultimate embedment at failure to load-to-grain angle. This second model is intended for predicting failure of timber joints. Comparison with test data confirms the suitability of these models to describe the influence of load-to-grain angle on embedment response of wood.
Ultrasonic Technique for Experimental Evaluation of Structural Integrity
Authors: Vangi D
Published: February 2009

An approach for an entirely experimental evaluation of the structural integrity of components or structures is presented. The approach is based on measurement, through ultrasonic techniques, of the effects induced on the local stress field by the presence of flaws in a structure. Due to the phenomenon of acoustoelasticity, such effects produce a variation in ultrasonic wave propagation velocity. From measurement of the wave propagation time within the material it is possible to calculate directly the stress intensity factors KI and KII, even in the case of mixed mode. The typical measurement chains for classic ultrasonic inspection are utilized in this approach. It is suitable in particular for utilization in conjunction with automated ultrasonic inspection techniques, inserting high-frequency transducers in the array of probes, and utilizing suitable analysis software. The results of tests conducted on specimens with fatigue cracks in different load conditions are reported.
The AMES Network Strategy Developments in the 5th Euratom Framework Program
Authors: Sevini F , Debarberis L , Törrönen K , Davies LM
Published: February 2009

The AMES (Aging Materials Evaluation and Studies) Network started its activity in 1993 with the aim of studying the consequences and the mechanisms of the aging process in materials used for nuclear reactor components. Together with ENIQ, NESC, and EPERC, it forms the so-called “Structural Integrity of Industrial Components” cluster of networks operated by the Joint Research Centre—Institute for Advanced Materials of the European Commission.

Initial activities of the network were the compilation of state-of-the-art reports on nondestructive monitoring techniques for thermal aging, dosimetry, survey of regulatory requirements, and predictive formulas for irradiation embrittlement as a result of in-kind contributions and projects cofunded by the 4th Euratom Framework Program. A brief overview of the outcome of these projects is given.

With the start of the 5th Euratom Framework Program. AMES has now entered its third strategy phase. Most of the projects approved by the Steering Committee and proposed to the Nuclear Fission Safety Key Action of the program to cover aspects of irradiation embrittlement and nondestructive monitoring were selected for funding.

Their focus is on the influence of chemical composition, namely phosphorus and nickel content, on the irradiation embrittlement of reactor pressure vessel materials, on the improvement of surveillance temperature measurement, on the validation of the master curve approach, and on nondestructive techniques to monitor aging of irradiated steels. The paper describes the objectives of the new 5th Framework Program projects and their matching with the AMES strategy, pointing out the involvement of CEEC and NIS countries.
Analysis of a High Rate Round Robin Based on Proposed Annexes to ASTM E 1820
Authors: Joyce JA
Published: February 2009

ASTM Committee E08 Task Group E08.08.02 has conducted a round robin to evaluate two new proposed Annexes to Standard E 1820. The round robin involved testing compact and three-point bend specimens at elevated test rates using servohydraulic test machines and then analyzing the resulting data using the normalization method proposed by Landes et al. The test rates were limited so that essentially static (noninertial) analysis could be applied to the results with the objective of obtaining J-integral resistance curves (J-R curves) consistent with those obtained by static tests presently sanctioned by E 1820. The normalization method fits an assumed form of function to the normalized load versus displacement relationship of each specimen and provides a technique to estimate the crack length at each data point. The so-called “normalization function” used is fit to data before crack growth initiates and to one point at the end of the test, for which the final measured crack length is assumed to be available. In this sense it acts as an interpolation scheme to estimate crack lengths and hence crack extensions for use in evaluating the specimen J-R curve.

Five laboratories participated in the round robin. Each laboratory was provided with two to four IT C(T) and/or SE(B) specimens of an A572 bridge steel for testing. Each laboratory was responsible for precracking and testing the specimens, loading the specimens at elevated loading rates between approximately 25 mm/s and 2.5 m/s, collecting the resulting load and displacement data, and analyzing the data according to the proposed normalization annex document prepared by Task Group E08.08.02. Specimen blanks were distributed during July 1998, and tests were run between late 1998 and late 2000 and the data were subsequently analyzed and the results returned. This paper describes the results of these individual analyses and an additional consistent analysis of the data sets completed by the author of this paper.

The objectives of the round robin were to determine if the high rate annex and the normalization method provided accurate and reasonable procedures for obtaining high rate loading J-R curves for structural materials. Since only one material could be tested in the round robin it was hoped that the participants, and possibly others as well, would use the procedures presented to analyze other materials for which they had data and interest. The results of the round robin demonstrated that the method does give good results for the test material, and that all participants were able to apply the method and obtain reasonable results. The author will discuss several weaknesses of the proposed Annexes that were uncovered in the course of the round robin or by other researchers during the past two years, and proposed corrections are presented that hopefully will address these shortcomings.
A New Multiparameter Approach to the Prediction of Wear Rates in Agricultural Sprayer Nozzles
Authors: Soboyejo ABO , Ozkan HE , Papritan JC , Soboyejo WO
Published: February 2009

A probabilistic multiparameter approach is presented in this paper for the prediction of the combined effects of multiple variables on wear rates in the material of agricultural sprayer nozzles. The methodology developed is based on the principles of stochastic processes in mathematical statistics, which essentially involve the statistical formulation of the mathematical models of wear rates as functions of the multiple random variables that may affect agricultural sprayer nozzle wear rates, and the determination of the constants of the probabilistic model using multivariate regression analysis.

A general empirical approach is proposed for the estimation of nozzle wear rate. The predictive capacity of the empirical approach is then verified by comparing the relevant theoretical model predictions with experimental data. When this exercise was carried out, excellent correlations were obtained between theoretical model predictions and experimental data. An important feature of the model is that assessments can be made for the relative contribution of the effect of each random variable on the total wear rate at any point in time. The importance of the new multiparameter models and the interdisciplinary collaboration of experts in the fields of structural materials, mechanics, and probabilistic methods in order to control and minimize wear rates in the design of nozzles for food production and agricultural engineering applications are also discussed.
Development of New Low-Cost Indirect Tensile Test Equipment for Bituminous Mixtures
Authors: Tigdemir M , Karasahin M , Kalyoncuoglu SF
Published: February 2009

In order to design pavements analytically, mechanical properties such as elastic modulus and Poisson's ratio should be known. In addition, fatigue and plasuc deformation life of bituminous mixtures have to be known. Marshall mix design, while abandoned in many developed countries, is still in use in Turkey. The reason for using the Marshall mix design is the lack of knowledge by highway authorities of other mix design methods, and the cost of change.

In order to minimize the cost of change, new low-cost indirect tensile test equipment has been developed that costs about one-tenth that of conventional equipment. The equipment is fully computer controlled and the control program was written by the first author. The load is controlled by a load cell, and the pressure is applied via an electronic pneumatic system. Deformation is measured by two LVDTs. The specimen size is the same as a Marshall specimen for the sake of easy sample preparation. However, if compaction equipment is available, other sample sizes can also be tested using the mold. In order to control the temperature in the cabinet, a digital thermostat that also shows the cabinet temperature on the screen is used. It is possible to apply square, haversinusoidal, and triangular waves to the sample.

Using different granular material gradations and temperatures, fatigue lives were obtained for analytical pavement design. As can be seen from the test results, the fatigue relationship does not have a good linear fit. Fatigue test results were interpreted in a different way using fuzzy set theory, which indicated that fatigue life can be predicted better than using the linear fit.
Determination and Calculational Minimization of the Nonlinearity of a Vis-NIR-Spectrophotometer Using the Double Aperture Method
Authors: Ossadnik S , Naundorf G , Schwedt G
Published: February 2009

The determination of the nonlinearity of spectrophotometers is essential for evaluating instrument performance. Nonlinearity is cause mainly by the detector system. Indirect methods, e.g., using calibrated filters or standard solutions, to determine these small deviations are not reliable for high-accuracy measurements. Typical uncertainties are in the order of ± 0.003 Abs. (0.5 to 1% of stated transmittance). The double aperture method is based on the principle of light addition. It is a direct method that requires no secondary transmission or concentration measurements. With the double aperture mask, two light beams are produced that can be measured separately or additively. In an ideal linear system, the sum of the separate readings is equal to the additive reading. The deviation in a real system represents a degree of nonlinearity. Through simple mathematical considerations a correction term can be found.

Using the double aperture method, the instrumental bias can be determined directly. While the measured systematic instrument error does not comprise additional uncertainties associated with the measurement of real samples, a calculational method to minimize instrument nonlinearity is shown.
Comparison of the Systems Approach and the Nordic Model and their Melded Application in the Development of Performance-Based Building Codes and Standards
Authors: Hattis DB , Becker R
Published: February 2009

The Systems Approach and the Nordic Model are methodologies that have been formulated and applied over the past 30 years to the development of performance-based building codes, standards, and specifications. Their respective use of similar terminology has differed, which has led to some confusion and has contributed to the perception that they are, in fact, quite different. Proponents of each methodology have occasionally stated this perception in public forums and by doing so have created the appearance of controversy. However, a comparative analysis of the Systems Approach and the Nordic Model demonstrates that they are, in fact, quite similar and complementary. They can be melded and applied in a productive manner to the current widespread development of performance-based building codes and standards.
Specimen Instrumentation Techniques for Permanent Deformation Testing of Asphalt Mixtures
Authors: Kaloush KE , Mirza MW , Uzan J , Witczak MW
Published: February 2009

This paper presents research efforts undertaken to develop, evaluate, and recommend proper laboratory specimen instrumentation and preparation techniques. The instrumentation was intended specifically to capture test parameters in permanent deformation tests for asphalt mixtures. The study evaluated axial deformation measurements and test parameters using the traditional clamps compared to on-specimen glued studs, both being holding devices for linear variable differential transformers (LVDTs). Sawed, “as compacted,” and capped specimen end conditions were also compared. The test results for specimens using clamps and/or capped ends indicated that the specimens were being restrained from deforming freely during the test. In addition, the permanent deformation parameters from both instrumentation types (clamps versus glued studs) were substantially different. The recommendation for permanent deformation testing of asphalt mixtures is to use the instrumentation setup with glued studs and sawed specimen ends with thin lubricated membranes at the ends to insure frictionless surface conditions.
Use of n-Propyl Bromide Solvents for Extraction and Recovery of Asphalt Cements
Authors: Stroup-Gardiner M , Nelson JW
Published: February 2009

Centrifuge extraction and Rotavapor recovery were used to determine the effect of solvent type (trichloroethylene and four n-propyl bromide products) on recovered asphalt binder properties. Mix variables included three binders mixed with each of two aggregate sources (one gradation). When recovered binder properties were compared to the original binder properties, the trichloroethylene solvent combined with the extraction and recovery processes occasionally produced higher (i.e., stiffer) recovered binders. One n-propyl bromide product appeared to be incompatible with the polymer-modified PG76-22. This incompatibility was seen as a distinct stringy, rubber like residue in the extractor. Fourier transform infrared analysis showed that this same product also seemed to inhibit or actually limit normal hear-related changes. Overall, the data indicate that n-propyl bromide solvents can be used as direct replacements for the chlorinated solvents historically used for hot-mix asphalt extraction and binder recovery.
Stress Pattern Analysis by Thermal Emission of Plain Weave Carbon Fiber/Epoxy Resin Composite Iosipescu Specimens with Three Different Notch Angles
Authors: Osborne MC , Moran AL
Published: February 2009

Iosipescu specimens were developed to examine the shear properties of isotropic materials. In the past decade, there has been much effort made to analyze this specimen configuration for measuring anisotropic materials, particularly laminated and woven composites. Some authors have used notch angles ranging from 90 to 110° in these materials and other authors have performed finite element analysis (FEA) to determine the notch angle and depth with the most uniform shear stress zone based on the elastic moduli. The object of this study was to verify the preferred angle of woven fiber composites through the use of stress pattern analysis by thermal emission (SPATE), which is a technique that can image the hydrostatic stress state in a material under load. SPATE images were collected for various specimens at different notch angles (90, 100, and 110°) and different weave lay ups. Mean load was held constant while the SPATE image was collected but later increased to examine the stress state of the Iosipescu specimens at high loads. The results indicate that for a plain woven carbon fiber/epoxy resin composite, the 100° notched specimen is the best specimen of the three conditions examined due to the delay in occurrence of damage and the large size of the pure shear zone.
Coarse Aggregate Shape and Size Properties Using a New Image Analyzer
Authors: Rao C , Tutumluer E , Stefanski JA
Published: February 2009

Automation of coarse aggregate shape and size determination using image analysis techniques is described in this paper as an alternative approach to current manual and time-consuming test procedures. A new image analyzer system, referred to as the University of Illinois Aggregate Image Analyzer (UI-AIA), uses a three-camera setup to view each aggregate particle from three orthogonal directions. Both volume (and therefore weight) and shape factors can be determined precisely for each particle based on sound image analysis and geometric principles. In addition, the grain size distribution of an aggregate sample can be determined. Tests conducted on ten aggregate samples were used to evaluate the perfor mance of the laboratory prototype UI-AIA in automating the standard ASTM D 4791-99, Standard Test Method for Flat Particles, Elongated Particles, or Flat and Elongated Particles in Coarse Aggregate and ASTM C 136-96a, Standard Method of Test for Sieve Analysis of Fine and Coarse Aggregates. The accuracy and repeatability of the imaging technique were evaluated for the computed aggregate volumes, percent by weight flat and elongated ratios, and gradation curves. Results from the new UI-AIA were in very good agreement with the manual measurements performed in two separate laboratories to ensure their exactness. The UI-AIA has scope for further modifications and improvements.
Homogeneous Unit Delineation for Interpreting Dynamic Cone Penetrometer Measurements
Authors: Divinsky M , Livneh M
Published: February 2009

The current investigation is concerned with the homogeneous unit delineation procedure for pavements and subgrade soils using dynamic cone penetrometer (DCP) data as widely employed in the evaluation of the pavement structure components. For the purposes of highlighting statistically homogeneous groups of the measurements along the registered DCP data profile, the conventional (AASHTO) cumulative difference approach procedure has been applied to the profile of DCP characteristic values. The delineating procedure shows significant sensitivity to the existing change in the mean value levels of the DCP measurements. Analysis of the procedure application to the profile of the DCP characteristic values (Penetration Index) and to the original number-of-blows values recorded during the DCP test has been done. The approach simplifies application of the AASHTO delineating procedure when using the original number-of-blows data during the DCP test. The approach produces the boundary position indication for the specific DCP characteristic profiles. Penetration characteristics for the delineated units have been used for predicting the California Bearing Ratio (CBR) parameter. The approach has been supported by Microsoft Excel spreadsheets for the semi-automated analysis of the DCP data and application of the delineation procedure.
A Screening Method for Ballistic Evaluation of Metallic Armor Materials
Authors: Singh BB , Bhat TB
Published: February 2009

This paper describes a quick and sensitive method for assessing the ballistic performance of materials. The method uses a tapered plate in which the thickness of the plate varies gradually from one end to the other.
Synthesis of Methane Hydrate in an Unconsolidated Medium
Authors: Siriwardane HJ , Smith DH
Published: February 2009

Under certain conditions of low temperature and high pressure, mixtures of small gas molecules and water form crystalline, ice-like compounds called clathrate hydrates. It is believed that large quantities of natural deposits of methane hydrate are formed in unconsolidated media from natural gas and water. Development of recovery techniques for this potential natural gas resource requires comprehensive laboratory investigations of engineering properties, which in turn require a capability for reproducibly synthesizing methane hydrate in unconsolidated matrix materials. This paper presents a procedure for synthesizing methane hydrate in an unconsolidated sand matrix. Results of dissociation experiments indicate that the samples prepared according to this procedure are relatively homogeneous and suitable for use in investigations of mechanical and other properties. The methane hydrate content and porosity of the samples can be controlled in the procedure developed.
Simulation of Irradiation Effects in Reactor Pressure Vessel Steels: the Reactor for Virtual Experiments (REVE) Project
Authors: Jumel S , Domain C , Ruste J , Van Duysen J-C , Becquart C , Legris A , Pareige P , Barbu A , Van Walle E , Chaouadi R , Hou M , Odette GR , Stoller RE , Wirth BD
Published: February 2009

Components of commercial nuclear reactors are subjected to neutron bombardments that can modify their mechanical properties. Prediction of in-service and post-service behaviors generally requires irradiation in so-called “test reactors” as well as subsequent mechanical testing in specialized hot cell facilities. However, the use of these research facilities is becoming more problematic, in particular due to increasing costs and decreasing availability. One way of partially mitigating these problems is to complement the empirical approach by developing tools for numerical simulation of irradiation effects in materials. The development of such tools is clearly an ambitious task that will require a long-term international collaborative effort.

In this paper, we present an outline of the Reactor for Virtual Experiments (REVE) project, a collaborative European and American effort aimed at developing quantitative simulations of irradiation effects in materials. The first demonstration phase of REVE will target embrittlement of reactor pressure vessel (RPV) steels, since the effects and mechanisms of irradiation damage in this material are relatively well understood and many modeling tools have been developed or are under development in this field. As for any experiment, the input variables of the REVE simulation will be the neutron spectrum, time and temperature of irradiation, the alloy composition (e.g., Cu, Ni, Mn, and C contents) and microstructure and the unirradiated mechanical properties. The simulations will predict the irradiation-induced increases of yield stress and Charpy transition temperature as well as the decrease of toughness due to the concomitant evolution of the microstructure.
Model-Fitting the Master Curves of the Dynamic Shear Rheometer Data to Extract a Rut-controlling Term for Asphalt Pavements
Authors: Shenoy A
Published: February 2009

The dynamic shear rheometer is currently being used by the asphalt community for determination of the viscoelastic properties of asphalts following the recommendations of the Strategic Highway Research Program. The Superpave specification parameter |G*|/sinδ was identified as the term to be used for high temperature performance grading of paving asphalts in rating the binders for their rutting resistance. However, this term was found to be inadequate in describing the rutting performance of certain binders, particularly, the polymer-modified ones. A refinement of the Superpave specification parameter for performance grading of asphalt led to the evolution of the term |G*|/(1 − (1/tanδ sinδ)). This performance-based specification term was shown to be more sensitive to the variations in the phase angle δ than the Superpave specification parameter and thus was found to describe the unrecovered strain in the binders more accurately, especially in the case of polymer-modified asphalts.

The high specification temperature THS (°C) is specified as the temperature at which the term |G*|/(1 − (1/tanδ sinδ)) takes a value of 1 kPa for the original unaged binder and a value of 2.2 kPa for the RTFOT aged binder. Though this refinement of the Superpave specification parameter has led to a better discrimination between the rutting resistances of various asphalts, it is found that not all asphalts that have been performance-graded as being the same behave identically in their rutting performance. Thus, there is a need to create a rut-controlling term that will distinguish between asphalts that are graded the same but prepared by different modification routes. Such a rut-controlling term can then be used as a performance-related specification.

The present work extracts the rut-controlling term by model-fitting the master curve formed from the |G*|/(1 − (1/tanδ sinδ)) or |G*|/(sinδ)9 versus frequency data at various temperatures for each binder. Each master curve is fitted with a constitutive equation from which model parameters are evaluated. The slope B1 in the low frequency region of the master curve is normalized with the term (T/THS), resulting in the rut-controlling term that relates to the permanent strain after 5000 cycles in the repeated shear at constant height experiment on the Superpave shear tester at temperature T.
Influence of Suction Dissipation on Compression of Compacted Rock Aggregates Due to Immersion
Authors: Yoshida N , Nishi M
Published: February 2009

This paper focuses on the influence of suction dissipation upon the development of compressive settling in compacted rock aggregates due to immersion. The influence of disintegration of the material upon the development of compressive settling is also addressed. For this, a staged compression-immersion test is carried out on compacted quartz porphyry as well as mudstone aggregates. The results show that for the quartz porphyry aggregates, the influence of suction is slight. For the mudstone aggregates, a relatively high suction exists initially, probably due to the inherent nature of this type of rock, and the influence of the dissipation of mere suction upon compressive settling could be smaller than that of disintegration or degradation of the aggregates.
Evaluation of the Uniaxiality of the Stress State in O-Ring Fracture Strength Specimens
Authors: Sipics MJ , Segall AE , Conway JC
Published: February 2009

To investigate the experimental implications of using O-ring specimens for evaluating the fracture strength of ceramics in tubular form, a statistically designed series of finite element analysis (FEA) calculations was performed. These calculations focused on the ranges of specimen dimensions and loading distributions required to maintain a uniaxial stress state within the O-ring specimen under diametral loading. Results of the FEA calculations indicated that the degree of uniaxiality of the O-ring stress state could be described completely by a combination of the depth-to-thickness ratio (b/t) and the inner radius-to-outer radius ratio (ri/rc). It was also found that a relatively wide range of geometries can be accurately used to extract fracture strength design data, provided b/t does not get too large nor ri/ro too close to zero. However, there is cause for concern when b/t→0 or ri/ro→1, as this implies a small sample of material (and flaws) in the critical tensile stress region. Results also indicated that the uniaxiality of the O-ring stress state followed the expected 1/v dependence so that the behaviors of different materials can be easily surmised from the current results. On the other hand, load magnitude did not seem to have any effect on the stress-state despite the Boussinesq-type loading, while the distribution of the load over a finite contact area section could.
Test Method to Determine Flammability of Aerospace Materials
Authors: Hirsch DB , Beeson HD
Published: February 2009

Qualitative correlations between ground upward flammability tests and flammability testing in microgravity indicate that the NASA STD 6001 Test 1 provides conservative results by sustaining flaming combustion in less severe environments than those in which extinguishment occurs in quiescent microgravity environments. The upward flammability test is conducted in the most severe flaming combustion environment expected in the spacecraft. Its pass/fail test logic does not allow a precise quantitative comparison with other ground or microgravity materials flammability test results. Thus, although reasonable from a flammability safety point of view, the test is likely to eliminate materials that may be safe for use on spacecraft. A different test logic that will determine materials self-extinguishment limits is suggested to address these impediments. Data to support this approach are presented, including self-extinguishment limits in concurrent and countercurrent flows and under quiescent conditions. The proposed method will allow continued use of existing NASA flammability data and make possible quantitative correlations between ground testing and microgravity test results. Quantitative correlations between ground test results and microgravity combustion data will improve the aerospace materials selection process and allow realistic estimates of spacecraft fire extinguishment requirements. Theoretical analyses of flaming combustion will be possible, leading to a better understanding of materials combustion. This will benefit not only the aerospace community, but also the combustion community at large.
Sensitivity Evaluation of a Disk-type Torque Transducer Used as a Transfer Device
Authors: Ohgushi K , Ueda K , Ota T , Katase Y
Published: February 2009

A torque transfer device is used for international comparison between torque standard machines or for comparison verification between a torque standard machine and torque calibration machine. This experimental study revealed a problem in the case of using a high-precision torque transducer as the transfer device. For a disk-type torque transducer, it was found that a considerable deviation in the torque output sensitivity occurred depending on the dimensions of the adapter flange and the fastening torque of the screw bolts directly connecting the torque transducer to the adapter flanges. A solution is proposed to overcome this difficulty.
The Influence of Laboratory Aging Method on the Rheological Properties of Asphalt Binders
Authors: Abbas A , Choi BC , Masad E , Papagiannakis T
Published: February 2009

Asphalt binders used in asphalt concrete roadway pavements experience aging during construction and subsequently during their service lives. Aging is the combined effect of the evaporation of volatile compounds and the chemical reaction of residual compounds with oxygen. This aging affects the rheological properties of asphalt binders. The SuperpaveTM testing and specification system uses two laboratory procedures for aging of binders prior to measuring their rheological properties, namely the rolling thin film oven (RTFO) and the pressure aging vessel (PAV). These two procedures are used to simulate the aging that takes place during construction and during service, respectively. This paper examines whether the SuperpaveTM prescribed sequence of binder aging procedures (i.e., the RTFO followed by the PAV) is necessary, or whether similar binder rheological properties are obtained using the PAV procedure only. For this purpose, three binders were tested, namely an unmodified PG 64-28, an SBS polymer-modified binder of the same grade, and an SBS polymer-modified PG 76-28. The low temperature and fatigue rheological properties were measured by a bending beam rheometer (BBR) and a dynamic shear rheometer (DSR), respectively. The findings of the study suggest that, with a few exceptions, the rheological properties measured after aging with the RTFO followed by PAV are significantly different than those obtained after PAV aging only.
Plastic Instability and Mechanical Anisotropy of Textured Zinc
Authors: Samba Siva Rao G , Godavarti PS , Mahmood ST , Linga Murty K
Published: February 2009

The influence of the material parameters, strain hardening, and strain-rate hardening on the plastic instability of textured zinc sheets tested in uniaxial tension was investigated. The experimental instability strains are observed to be in accord with those evaluated from the analytical expressions involving the material parameters. The crystallite orientation distribution function obtained from the pole figure data is used in conjunction with a plasticity model to predict the anisotropy parameters (R and P) and subsequently the width strains in longitudinal and transverse zinc sheets. While the experimental R and P values matched well with those predicted for basal slip, the predicted width strains beyond uniform deformation are observed to be higher than the experimental values.
Dynamic Loading Fracture Tests of Ferritic Steel Using the Direct Current Potential Drop Method
Authors: Oh YJ , Kim JH , Hwang IS
Published: February 2009

To apply the leak-before-break concept to nuclear piping, the dynamic strain aging of low alloy steel materials has to be considered. For this goal, J-R tests are needed over a range of temperatures and loading rates, including rapid dynamic loading conditions. In dynamic J-R tests, the unloading compliance method cannot be applied and usually the direct current potential drop (DCPD) method is used. But, the DCPD method is known to have a problem in defining the crack initiation point due to a potential peak that arises in the early part of loading of ferromagnetic materials. In this study, the characteristics of measured DC potential peaks were investigated for SA106 Gr. C piping steels, and the definition of crack initiation point was determined by backtracking from the physically-measured final crack length. It is proposed that this technique could be applied as an improved DCPD method applicable for the dynamic loading J-R test.
Instrumental Method to Evaluate Leather Compressive Properties
Authors: Chen Y
Published: February 2009

An instrumental attachment and testing method was developed on a QTest™ tensile tester to evaluate leather compressibility. Six types of leather including pig, deer, cow, emu, goat, and alligator, were tested in terms of compressive modulus, linearity, energy, resilience, and thickness. A linear function was proposed to characterize the relationship between logarithmic stress and strain. This enabled calculation of all initial compressive moduli for these leather samples. The instrumental obtained data helped comparison of the compressive properties among the leather samples.
Simulation and Prediction of Hardness Performance of Rockwell Diamond Indenters Using Finite-Element Analysis
Authors: Ma L , Low S , Zhou J , Song J , deWit R
Published: February 2009

The difficulty in manufacturing Rockwell diamond indenters to the required geometric specifications has resulted in most commercially manufactured indenters to vary in shape from one to another. This difference in shape is thought to be a major contributor to the Rockwell C scale hardness measurement uncertainty. In this paper, a finite-element analysis (FEA) is used to simulate the Rockwell hardness measurement process. The influences of the indenter's geometry, including tip radius, cone angle, and form error on Rockwell hardness tests are analyzed by the FEA model, and further verified by experimental results. A new method is developed to directly input the Rockwell indenters' profiles into the FEA model for hardness performance prediction. The prediction results show good agreement with NIST experimental results.
Investigation of Stress-Strain Relationship of Confined Concrete in Hollow Bridge Columns Using Neural Networks
Authors: Mo YL , Hung HY , Zhong J
Published: February 2009

Typically, material modeling has involved the development of mathematical models of material behavior derived from human observation of experimental data. An alternative procedure, discussed in this paper, is to use a computation and knowledge representation paradigm, called a network, to model material behavior. The main benefits in using a neural network is that the network is built directly from experimental data using the self-organizing capabilities of the neural network, i.e., the network is presented with the experimental data and learns the relationships between stresses and strains. Such a modeling strategy has important implications for modeling the behavior of complex materials. In this paper, the stress-strain relationship of confined concrete in hollow bridge columns is modeled with a back-propagation neural network. The results of using networks to study the behavior of confined concrete look very promising.
Analytical Model for Fatigue Crack Propagation in Concrete
Authors: Ramsamooj DV
Published: February 2009

A new approximate analytical model is presented for the fatigue crack propagation rate in concrete. The model considers fatigue cracking at all stress levels up to the modulus of rupture. As the bending stress increases, the size of the inelastic zone compared to the crack length increases, and the stress intensity factor no longer controls the stresses in the vicinity of the crack tip, necessitating the use of the path-independent J-integral. At high stress levels fatigue crack propagation becomes nonlinear, and fracture may occur by ultimate strength collapse. Recently Kharlab postulated a hypothesis that enables the prediction of fracture of concrete by a single criterion that considers failure at any stress level for any size beam.

An approximate analytical method for fatigue crack propagation in concrete at any stress level is presented. It incorporates the size effect and uses the crack tip opening displacement as the primary criterion upon which the rate of crack propagation is dependent. The model is validated by the published experimental data on concrete fatigue.
Evaluation of Bearing Capacity Improvement Using Composite Grids
Authors: Sivakumar Babu GL , Srinivasa Rao BM , Sridharan A
Published: February 2009

Recently, composite reinforcements in which combinations of materials and material forms such as strips, grids, and strips and anchors, depending on requirements, have proven to be effective in various ground improvement applications. Composite geogrids studied in this paper belong to the category of composite reinforcements and are useful for bearing capacity improvement. The paper presents evaluation of results of bearing capacity tests conducted on a composite geogrid, made of composite reinforcement consisting of steel and cement mortar. The study shows that the behavior of composite reinforcements follows the general trends observed in the case of conventional geogrids, with reference to the depth of first layer below the footing, number of layers of reinforcement, and vertical spacing of the reinforcement. Results show that the performance is comparable to that of a conventional polymer geogrid.
Stress Concentration Factor Formulas Useful for All Notch Shapes in a Flat Test Specimen Under Tension and Bending
Authors: Noda NA , Takase Y
Published: February 2009

In this work, stress concentration factors Kt for a flat bar with circular-arc or V-shaped notches are considered based on the exact solutions for special cases and accurate numerical results. Then, a set of Kt formulas useful for any notch shape is proposed. The conclusions can be summarized as follows. For the limiting cases of deep (d) and shallow (s) notches, the body force method is used to calculate the Kt values. Then, the formulas are obtained as Ktd and Kts. Next, the notch shape is classified into several groups according to the notch radius and notch depth. Then, the least squares method is applied for calculation of Kt/Ktd and Kt/Kts. Finally, convenient formulas are proposed that are useful for any notch shape in a flat test specimen. The formulas yield stress concentration factors with less than 1% error for any notch shape in a flat test specimen.
Ring Hoop Tension Test (RHTT): A Test for Transverse Tensile Properties of Tubular Materials
Authors: Wang H , Bouchard R , Eagleson R , Martin P , Tyson WR
Published: February 2009

Tube hydroforming has been receiving increasing attention, particularly for making automotive components. In this process, tubular metal pats are formed within a die cavity by forcing pressurized fluid inside so that the part expands into its final shape in a die. Process control requires an improved knowledge of mechanical properties in the transverse direction of tubular products. Several laboratory tests have been used to evaluate tube properties. One test method that has been used for zirconium alloy cladding tubes in the nuclear industry is the ring test, in which an expansion force is applied from inside the ring by separating two die inserts. In the present work, this test method is adapted to determine the hoop stress-strain curve of tubular materials. The new protocol allows measurement of the tensile properties without altering those properties in specimen preparation, which occurs using the conventional flattened strip tensile test. This paper presents the new test and data analysis procedure, along with typical data for a commercial steel hydroforming tube.
Experimental Analysis of Multiple Staple Joints in Selected Wood and Wood-Based Materials
Authors: Yadama V , Zhang J , Syed BM , Steele PH
Published: February 2009

Effects of the number and spacing between staples on withdrawal and lateral resistance of stapled joints were investigated for selected wood and wood-based materials. Galvanized staples with legs that were 1.59 mm in diameter (16-gage wire) and 38 mm (1.5-in.) in length, and had chisel-end points, were used to construct the joints. Spacings between staples of 3.18 mm (1/8-in.) and 6.35 mm(1/4-in.) were tested. One, two, four, or eight staples were used to fasten the joint members that were of the following materials: Eastern cottonwood (Populus deltoides), red oak (Quercus falcata), yellow poplar (Liriodendron tulipifera), sweetgum (Liquidambar styraciflua), medium density fiberboard (MDF), and oriented strandboard (OSB). Direct withdrawal and lateral resistances of the joints were evaluated.

Results indicated that, on the average, joints with higher density members provided the most resistance to withdrawal and lateral loads. Number of staples positively affected the joint resistance for all materials for both spacings, however, the relationship was not linear for most materials. General linear regression models, using material type and spacing as indicator variables, were developed to predict the withdrawal and lateral resistances.
Data Supporting a Provisional ASTM Method for Metalworking Fluids Part 3. Evaluation of an ASTM Method for Metalworking Fluids in a Survey of Metalworking Facilities
Authors: Glaser RA , Shulman S , Kurimo R , Piacitelli G
Published: February 2009

An interim ASTM method for analysis of metalworking fluids was evaluated for estimation of personal exposure concentrations in a 79-plant survey of machine shops and metalworking facilities across the United States. Both thoracic and total particulate samples were collected on tared polyte trafluoroethylene filters. Metalworking fluid concentrations were estimated by determination of the total- and extractable-sample weights using ASTM Method PS-42-97. This procedure employs a temary solvent blend of dichloromethane:methanol:toluene to separate the fluids from comingled insoluble particulate. Following the initial extraction, reextraction of 322 samples with the ternary solvent removed, on average, <2.5% of the sample weight, indicating that the majority of extractable material had been removed during the first extraction. Evaluation of the field study blank data permitted estimation of the mean, median, and upper 95th percentile of the limits of quantitation to be 0.1 mg, 0.1 mg, and 0.3 mg, respectively, for both the total weight and the extractable weight samples.

For the 79-plant survey, the fractions extracted (weight extracted/weight of sample) were studied as a function of four metalworking fluid types and three main work operations—grinding, milling, and turning—according to a restricted maximum likelihood statistical procedure. This evaluation of the data indicated that the fractions extracted generally decreased in the order: straight > semisynthetic or soluble > synthetic; the differences in the fractions extracted for the straight and the synthetic fluids were statistically significant only for the grinding operation at two sample levels tested.

Studies of the stability of quality assurance (QA) samples spiked separately with a straight, a soluble, a semisynthetic, and a synthetic fluid indicated that the QA samples all lost weight according to simple linear decay equations. These decay equations were used to estimate the amounts expected to be reported for QA filters by the performing laboratory. For storage periods ranging from 18–26 days, the total weight of sample recovered for each QA sample was ≥80% of that expected from the decay equations. For these QA samples, the fractions extracted (extracted weight/total sample weight) from all four fluid types were ≥0.90.
Review of: Wear Analysis for Engineers
Authors: Blau PJ
Published: February 2009

The objective and intended audience for this book are clearly stated in the Preface: “This book is intended to explain the wear analysis method and its implementation and to provide sufficient information for the performance of most wear analyses. It is intended primarily for engineers.” Perhaps, the phrase “author's wear analysis method,” should probably be substituted in place of “the wear analysis method,” which implies that there is only one. In fact, there are several handbooks and tribology texts on the market today that describe some form of wear analysis. While the author's approach shares many key attributes with the others, it represents a unique perspective gained after 40 years of experience in the field of tribology. The approach he provides is sufficiently general to cover a wide range of wear problems.