bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression for the Dynamic Yield Stress from Instrumented Dynamic Tear Specimens and Plastic η-Factor for Three-Point Bend Specimens: Results for AISI 308 Weld and AISI 316 Stainless Steels
Authors: Sreenivasan PR , Ray SK , Mannan SL 
Published: February 2009

Abstract
An empirical expression for computing the dynamic yield stress, σyd, from the general yield load, PGY, of dynamic tear (DT) specimens has been derived by comparing the results from instrumented drop-weight/impact tests of DT and Charpy V-notch (CVN) specimens of AISI 308 weld and AISI 316 stainless steels. This is based on the following assumptions: the functional expression relating σyd to PGY is the same for both DT and CVN specimens except for a dimensionless proportionality constant: and σyd from both the specimens has the same value. Plastic η-factors obtained by analyzing instrumented DT test results are also presented. The work reported earlier by the authors based on instrumented CVN and precracked Charpy specimen test results showed the dependence of the plastic η-factor on the crack aspect ratio; the present results indicate that the plastic η-factor shows an additional specimen size dependence. However, the new estimates based on the larger size specimens are only slightly larger than the lower-bound estimates reported earlier, but much below the upper-bound curve reported at the same place. Similar size dependence has been reported in the literature.
Measurement of Relative Surface Roughness at Particulate-Continuum Interfaces
Authors: DeJong JT , Frost JD , Saussus DR 
Published: February 2009

Abstract
The shearing behavior at particulate-continuum interfaces is influenced strongly by the continuum surface roughness. To date this surface has been characterized with absolute roughness parameters that represent various aspects of the spatial distribution of surface features. However, for particulate-continuum interfaces, the effect of continuum surface roughness on interface behavior is itself dependent on the particulate material characteristics. This interaction suggests that the surface roughness be characterized in relation to the contacting particulate material. Filtering algorithms such as low-pass and high-pass filters are frequently used to isolate components of a surface profile such as waviness and roughness. However, these filters consider peaks and valleys of a surface profile equally and hence implicitly assume each feature has the same effect on the interface behavior. An extensive analysis that traces the centroids of different diameter particles as they traverse across surfaces is presented herein. The resulting observations include: (1) peaks and valleys on a surface affect particulate-continuum interactions differently; (2) conventional surface roughness parameters do not account adequately for the characteristics of the contacting particulate material; and (3) conventional filters incorrectly isolate surface features of interest in particulate continuum interfaces. A framework that allows for these issues to be considered in evaluating the relative roughness of surfaces is presented.
Flexural Characteristics of Sunlight-Aged Polyester Composites: Influence of Processing Variables
Authors: López FS , Ferrer C , Salvador MD , Amigo V 
Published: February 2009

AbstractThis work presents the results of flexural tests carried out on samples aged for different periods of time in a UV-Visible light chamber. The processing variables studied were the type of reinforcing fabric, the resin type, and the cure conditions. The evolution of flexural characteristics with time exposure adjusts to a mathematical model that corresponds to a damped exponential curve. The aging degree varies between 16 and 41%, depending on the preparation of the composites and the mechanical characteristics of the material. The aged material featured losses of its mechanical properties, and more on toughness than on strength properties. The kind of unsaturated o-phthalic polyester resin used showed no influence on the loss of mechanical properties. High cure temperatures decreased the loss of toughness to a higher degree than that observed for the loss of strength. The configuration of the reinforced fabrics used also influenced the mechanical properties: a mixed taffeta-multiaxial reinforced configuration leads to a high loss index on toughness properties and modulus of the composite.
Verification of Thin-Wall Ductile Iron Test Methodology
Authors: Schrems KK , Doğan ÖN , Hawk JA 
Published: February 2009

Abstract
Modifications need to be made to standard test procedures to determine the actual properties of thin-walled ductile iron castings. A series of experiments was performed on test bars to examine the effects of surface finish, elongation measurement techniques, and the amount of material removed during grinding. A paired t-test was used to show that strength and ductility increased as a result of removing the as-received (as-cast) surface. This is attributed to inaccuracies in measuring the cross section area of the rough surface as well as an actual increase in strain through removal of surface effects. A nontraditional method of measuring elongation (to retain the fracture surface) was compared to the standard ASTM method. The nontraditional method was found to be a conservative measure of elongation that is highly correlated with plastic strain as measured by the stress-strain curve. The amount of surface removed during grinding was found not to affect the mechanical properties with the exception of hardness, a surface measurement. It is suggested that thin-walled castings be tested in the condition the casting will be used, i.e., if the casting will be used with the as-cast surface, testing with the as cast surface will accurately reproduce the decrease in strain caused by the surface effects. If the casting will be ground before use, any amount of surface can be removed to make the testing convenient.
Effect of the Aging of the “Product/Package” System on the Mechanical Properties of Plastic Packaging
Authors: Ayad R , Safa L , Bureau G , Marull S 
Published: February 2009

Abstract
The influence of aging of four cosmetic formulations on the mechanical properties of plastic packaging is studied. Four thermoplastic materials in the form of bottles were used: polyethylene, polypropylene, polyethylene terephthalate, and polyethylene terephthalate glycol copolymer. Bottles were filled with cosmetic formulations and put into a steam room at 42°C for 15 days, 1 month, 2 months, and 3 months. Periodically, bottles were emptied, and mechanical properties and performances (tensile test, compression, and under-pressure tests) were studied as well as the wall thickness, the glass transition temperature (Tg), the crystallinity, and the kinetic sorption by Fourier transform infrared spectrometry. A significant change of mechanical properties was observed after the sorption of cosmetic components into the materials: this change depending on the type of material (especially for polyethylene and polypropylene) and on the cosmetic formulation. These changes must be minimized, particularly in the light of reducing packaging weight. This work leads to a new optimization methodology permitting the anticipation of packaging design.
Using X-ray Computerized Tomography for Characterization of Defects in Cartridge Filters
Authors: Maschio C , de Arruda ACF 
Published: February 2009

Abstract
Cartridge filter manufacturers conventionally use air permeability and bubble point tests for the evaluation of integrity and filtration rating of their filter elements. These tests reveal information only upstream and downstream of the filters. If a region of low density and a region of high density (compared to the mean density of the filter) exist in the interior of the element, these two regions may be superimposed and the results of the test may cause acceptance of an imperfect filter. The present paper shows the use of an X-ray computerized tomography scanner for visualization of internal defects in the cartridge filter elements used in industrial and domestic applications. Tomographic images with good contrast were obtained. The images clearly revealed cracks in the activated carbon filter and regions of high density in the fibrous filter (meltblown type). Finally, the main objective of this paper is to show that X-ray computerized tomography can be used successfully within the filter industries as a potential tool in the evaluation of existing products, and as a support in new product development.
Evaluation of an Accelerated Pavement Testing Facility and Development of its Load Equivalence Factors
Authors: Chen J-S , Lin K-Y 
Published: February 2009

Abstract
An accelerated pavement testing facility (APTF) was used to simulate the effect of traffic on pavement performance. An enhanced procedure was developed in this study to calculate the load equivalence factors (LEF) for APTF. Results indicated that this procedure is feasible to evaluate the effect of heavy axle loadings on pavement performance under an accelerated rate. The pavement performance after APTF followed the trend observed on full-scale test roads. Based on the present serviceability index loss of the APTF data, it was found that an eighth-power law existed for the APTF in contrast to the fourth-power law in full-scale test roads. This implied that the LEF for APTF single axle loads of the same configuration was equal to the ratio of the axle weights raised to the eighth power. This finding explained why pavements tested by the APTF failed much faster than regulated loading. Critical loads, however, appeared to be present for pavements tested by the APTF. Pavements tested with loads greater than the critical load might fail predominantly by traffic loading.
Fatigue Crack Growth in Cantilever Bending Under Displacement Control
Authors: Abd-Allah NM , Megahed MM , Eleiche AM 
Published: February 2009

Abstract
Fatigue crack growth (FCG) behavior of two martensitic steel grades was investigated using a single edge-notched bend specimen fixed beyond the notched section in cantilever bending under displacement control. This task was made possible by a new and original testing methodology developed on the basis of finite element analyses to define valid boundary conditions and the corresponding stress intensity factor K-expression for the test specimen. The behavior has been described including the nearthreshold zone and the second zone of relatively high FCG rates. Results for the two steel grades were found to correspond well with the empirical models reported in the literature. This confirms the validity of the methodology proposed in the present paper, which can be attributed to: (1) the accurate K-expression for the test specimen, (2) the proper definition of the boundary conditions adopted during testing, and (3) the validity of the adopted boundary conditions.
Correlating Permanent Deformation Characteristics of Hot Mix Asphalt with Aggregate Geometric Irregularities
Authors: Kuo C-Y 
Published: February 2009

Abstract
Regression analyses were performed to study the correlation between the permanent deformation characteristics of hot mix asphalt (HMA) mixtures and their aggregate geometric irregularities. Permanent deformation of HMA mixtures was characterized by permanent strain, creep modulus, and slope of the creep curve from unconfined repeated load deformation tests. The fine aggregate angularity (FAA) test was used to characterize fine aggregates while coarse aggregates were characterized with either the particle index (PI) test, the modified National Aggregate Association flow test (modified NAA), or image analysis. Regression analyses indicate strong correlation between the permanent deformation characteristics of HMA mixtures and the aggregate geometric irregularities. Use of imaging indices for characterizing coarse aggregates gives better coefficients of determination than do other coarse aggregate characteristics such as PI and modified NAA. The imaging indices have major potential in evaluating aggregate geometric irregularities for engineering analysis.
Scheduling of Pipelined Data Paths for On-line Testability
Authors: Ismaeel AA 
Published: February 2009

Abstract
This paper presents a time-constrained scheduling of a pipelined data path with the perspective of improving on-line testability. The testability is incorporated at the scheduling phase of the synthesis. Being a presynthesis method, the approach minimizes the area overhead. Operations of the same type are assigned to resources called functional units (FU). The on-line testing is carried out by capturing selective input and output variables of a circuit under test (CUT) in time frames called passes. The captured variables are shifted out to an external testing unit for verification. Each FU of the CUT is tested at least once in each pass. Minimizing the number of variables needed to test all FUs reduces the testing time. Thus, the scheduling is performed with the objective of improving on-line testability by minimizing the number of FUs and the number of variables needed to test all FUs. Promising results are obtained on benchmark examples.
Photoelastic Evaluation of Stress Fields and Fracture During Dynamic Splitting Experiments
Authors: Gomez JT , Shukla A , Sharma A 
Published: February 2009

Abstract
Dynamic tensile-splitting experiments were conducted on brittle polyester disks, manufactured from Homalite ®-100, to photoelastically visualize stress field development in the specimens and, ultimately, specimen fracture. A Split Hopkinson Pressure Bar (SHPB) was used to load the specimen dynamically and record load data as a function of time. Images of the stress field were captured with high-speed photography and interpreted using photoelastic analysis. The experiments determined that the specimens reached an equilibrium state relatively quickly, and remained in equilibrium until fracture. Fracture began with in-plane cracks forming on either side of the specimen. Transverse cracks emanated from the in-plane cracks, then propagated across the specimen mid-plane at velocities up to 60% of the shear wave velocity in the material. Contact loads calculated from photoelasticity agreed favorably with SHPB results. These experiments also allowed for the determination of the dynamic splitting strength of the Homalite ®-100 as a function of strain rate. The dynamic splitting strength of the material increased with the increasing strain rate, reaching a maximum value of about twice the static splitting strength.
Application of a Relativistic Conservation Equation to Crack Initiation
Authors: Ullrich G 
Published: February 2009

Abstract
Given the load versus deformation diagram, including the load maximum of a specimen with a known stress intensity factor, the initiation of stable crack growth can be calculated exactly from measurement results by introducing equations analogous to those found in the theory of general relativity. This can be done by means of the two-observer principle. A point on the plastic curve can be equivalently correlated to a given point on the elastic curve. In deriving the equivalence, it can be seen that the different geometrical configurations with respect to the loading direction and the crack plane have to be modified by the introduction of a factor. It was found that this factor is analogous to the Doppler effect (Lorentz transformation.) The agreement of the mathematical procedure using analytical functions with the experimental results (potential-drop technique) has been found to be excellent, using qualified steels. For those materials with significant deformation before crack initiation, the agreement between mathematical procedure and experiment is less good.
Influence of Hot-Mix Asphalt Parameters on the Correction Factors of the Ignition Oven Test
Authors: Sabaaly PE , Abdel-Magied O , Dunn M , Brinkmeyer W 
Published: February 2009

Abstract
The ignition oven method has been gaining popularity because of its applicability to both laboratory and field conditions, its nondependency on chemicals, and its ability to evaluate both binder content and aggregate gradations. However, the use of this method requires the careful determination of correction factors for both binder content and aggregate gradations. The need for such correction factors stems from the fact that most aggregates experience a certain level of weight loss as they are subjected to elevated temperatures. These weight losses must be accounted for in order to accurately determine the binder content and aggregate gradation of HMA mixtures. It is well accepted that the most important step of the ignition oven test is the determination of an accurate correction factor. The implementation of the ignition oven method requires the highway agency to assess the performance of the local materials with the test procedure and to identify the mixture parameters that significantly impact the determined correction factor. In preparation for the implementation of the ignition oven test, the Nevada Department of Transportation (NDOT) conducted an extensive laboratory testing program to assess the impact of the various mix parameters on the determination of the correction factors. The experiment included aggregate source, binder type, lime, and testing temperature. This paper analyzes the data generated from the NDOT experiment and evaluates the impact of each of the considered factors on the correction factor. In summary, the analysis of the data generated in the NDOT experiment showed that the aggregate source and the addition of lime have the most significant impact on the determined correction factor followed by the temperature and binder type. However, if during a field project the binder or the method of lime application changes, this change would not require the determination of a new correction factor. The data also showed that the blank aggregate method would generate correction factors that are less variable than the known asphalt content method.
Staged Compression-Immersion Direct Shear Test on Compacted Crushed Mudstone
Authors: Yoshida N , Enami K , Hosokawa K 
Published: February 2009

Abstract
This paper introduces a staged compression-immersion-direct shear test carried out in order to deal with compressive settlement phenomena of compacted crushed mudstone during staged filling and due to immersion from the viewpoints of not only deformation but also shear strength deterioration. The test apparatus and procedure are described, and as an example, compacted crushed Kobe mudstone samples are tested. It is shown that as expected, the crushed Kobe mudstone samples compacted with 95% degree of compaction exhibit larger compressive settlement than those compacted with 100% degree of compaction during staged loading, and that only the former samples show additional compression due to immersion. Shear strength decreases due to immersion being accompanied with volume decrease, and the shear strength decrease and volume change are larger in the samples compacted with 95% degree of compaction. It is also indicative that the shear strength of the aggregate itself has a significant influence on the shear strength of its compacted samples.
Measurement of Creep Damage by the Natural Frequency Method
Authors: Ling X , Tu S-t 
Published: February 2009

Abstract
The natural frequency method (NFM), a novel approach for the measurement of creep damage, is proposed in this paper. The technique, with instrument configuration and experimental procedure, is described in detail. The application of the approach has been made on 25Cr20Ni steel, widely used for furnace tubes. The measured results of creep damage show good agreement with theoretical predictions. The critical damage value ωcr of 25Cr20Ni also has been obtained by the proposed approach. Compared with the current density method and the loading and unloading method, NFM has many advantages, such as higher accuracy, simpler apparatus, and better repeatability. On the basis of NFM, an efficient approach can be given for life prediction and extension of high temperature components.
Experimental Evaluation of the Torsion Test for Determining Shear Strength of Structural Lumber
Authors: Gupta R , Heck LR , Miller TH 
Published: February 2009

Abstract
The torsion test was evaluated as a method for determining shear strength of full-size, structural lumber by length and depth studies. The length study consisted of fifty 38 by 89 mm specimens, ten each of lengths 0.5 m, 0.7 m, 0.8 m, 0.9 m, and 1.0 m, and ten shear blocks. The statistical analysis showed no evidence that length affected shear strength. The depth study consisted of 50 specimens, ten each of sizes 38 by 89 mm, 38 by 140 mm, 38 by 184 mm, 38 by 235 mm, and 38 by 286 mm, and 50 shear blocks. The statistical analysis did not show convincing evidence of a depth effect on shear strength, even after accounting for specific gravity and shear span as covariates. Failure modes were similar to shear failures observed in bending tests, and involved a longitudinal shear crack at the wide face, which propagated toward the ends of the specimens and through the cross section perpendicular to growth rings. Based on results of this study, the torsion test is the best practical method for determining pure shear strength of full-size, structural lumber.
Finite-Element Analysis of the Stress Distribution in a Torsion Test of Full-Size, Structural Lumber
Authors: Gupta R , Heck LR , Miller TH 
Published: February 2009

AbstractFull-size structural lumber under torsion was analyzed using the finite-element method to determine stress distribution. A three-dimensional, homogeneous, orthotropic finite-element model was developed and analyzed using commercially available software, ANSYS®, to increase understanding of stress distribution and failure modes. Analyses revealed that uniform shear stress occurs within the shear span, which begins and ends at a distance of approximately two times the depth plus the grip distance away from each end of the specimen. In addition, finite-element analysis verified that the experimental shear-failure plane that occurs within the shear span is parallel to the grain. Shear slippage is also parallel to the grain, similar to the known shear-failure mode in specimens subjected to transverse loads. Based on results of this study, the torsion test is the best practical method to determine the pure shear strength of full-size, structural lumber.
Effect of Anisotropy on Compressive and Tensile Properties of Asphalt Mixtures
Authors: Mamlouk MS , Witczak MW , Kaloush KE , Ho Y-S 
Published: February 2009

Abstract
The research effort in this paper was part of the Superpave Support and Performance Models Management Project (Advanced Material Characterization) and was funded by the National Cooperative Highway Research Program Project 9–19. Anisotropy of hot mix asphalt materials greatly depends on specimen preparation, testing conditions, and test parameters under consideration. The objective of this study was to evaluate the anisotropy of selected test properties for specimens specially prepared with the Superpave gyratory compactor and cored in the vertical, horizontal, and diagnonal directions. The number of gyrations during compaction was adjusted on a trial-and-error basis to produce cores having air void contents of 4.0 ± 0.5% regardless of the direction of coring. Confined compression and tension tests were performed on the cored test specimens. The analysis included parameters such as the compressive / tensile strength, modulus of elasticity, and strain at failure. All test results were analyzed statistically. The majority of the test results (compression and tension) showed no significant effect of test specimen orientation on the test parameters at the 5% level of significance and for the test conditions used in the study. These results indicated that anisotropic effects might be ignored for the asphalt mixture used in this study using the special preparation method in the Superpave gyratory compactor.