bluuebunny/crossref_metadata_2025 huggingface dataset:
Fatigue and Creep Crack Growth in Fine Sand Asphalt Materials
Authors: Kleemans CP , Zuidema J , Krans RL , Molenaar JMM , Tolman F
Published: February 2009

Fatigue and creep crack growth experiments in sand asphalt specimens have been performed in four-point beading and center cracked tensile setups. Specimen thickness, frequency, and R values were varied. Most of the tests were constant load experiments, but a constant ΔK experiment was also performed.

It was found that Paris law matches the results. Specimen thickness does not affect the results. Results of tests at different frequencies can be reduced to a single scatter band by plotting da/dt(= f · da/dN) instead of da/dN versus ΔK. Different R values can be brought together by a parabolic crack closure relation. It is concluded that the dominant cause of crack growth in this type of asphalt, under the investigated circumstances, is creep.
Regression Analysis as an Aid in Making Oboe Reeds
Authors: Ceasar-Spall K , Spall JC
Published: February 2009

Professional oboe players almost always have to make their own reeds, which involves a time-consuming process often fraught with wasted effort and discarded results. About one fourth of the total time spent on a reed involves getting it to a stage where it can be tried out on the oboe. Regression analysis was used to aid in making predictions about the ultimate quality of a finished reed based on data available at the initial try-out. The inputs to the regression model consist of several different characteristics of the cane used in making the reeds, and an assessment of the reed in its early stages through this initial try-out on the oboe. The goal to be able to decide whether or not to continue to work on the reed past this stage, based on the predictions of the regression. Thus far, the outcomes predicted by the regression have coincided reasonably closely with the actual outcomes in trials. Several regression models were tried, ranging from pure linear to curvilinear models that include interaction terms and/or squared terms. A particular curvilinear model was deemed the most appropriate.
Development of a Road Roughness Profile Delineation Procedure
Authors: Divinsky M , Nesichi S , Livneh M
Published: February 2009

There are several approaches to delineation of statistically homogeneous units for pavement response variables in a selected property, and one of them, the cumulative difference approach, is presented in the AASHTO Guide for Design of Pavement Structures (1993). This method is a relatively powerful analytical one, when the nature of the measurements involves delineating homogeneous units with different mean value levels. However, there are other cases when the delineation procedure should be applied for data with different levels of scatter characteristics, such as with standard deviation or range. This modified cumulative difference approach is fully described in this paper with application to delineating statistically homogeneous units along a road profile of roughness measurements. The suggested approach provides an advantage in delineating scattered characteristics and shows a high level of efficiency as evidenced by practical applications. The results presented are expected to serve as a basis for enhancing quality control criteria in the construction, as well as in the maintenance stages. Another goal is to serve any advanced pavement management system (PMS).
Effective Vulnerability Assessment of Tamper-Indicating Seals
Authors: Johnston RG
Published: February 2009

Security seals are widely used to detect tampering or unauthorized entry. In the author's view, existing standards for vulnerability assessment of security seals are incomplete. This paper discusses the critical attributes of effective vulnerability assessment. These include: a clear understanding of what seal vulnerability assessment is and why it is undertaken; use of appropriate assessment personnel; assessment at the earliest possible stage of seal development; analysis conducted with the proper emphasis and context; rejection of findings of zero vulnerabilities; avoidance of the term “tamper-proof”, characterization of the degree of defeat; and thorough reporting of findings.
Evaluation of Elastic Stress Intensity Using J-Integral Specimen Geometries
Authors: Joyce JA , Smudz R
Published: February 2009

The development of a “Common Test Method” for fracture mechanics toughness evaluations requires changes in the test specimens used for evaluation of the elastic critical stress intensity factor KIc. The present method. ASTM E 399, does not allow the use of side grooves and load-line crack opening displacement measurements as is common and necessary for J-integral and CTOD elastic-plastic fracture methods like ASTM E 813. E 1152, and E 1290. This paper presents experimental data on two materials that demonstrate that the J-integral type specimen can be used to evaluate KIc in an accurate fashion and that hence a true “Common Method” is possible.

The basic conclusions are that if the secant offset slope is varied to correspond to 2% crack growth, the KQ values measured from specimens with a/W ratios between 0.55 and 0.7 are indistinguishable from standard results. Side grooves do not affect the results as long as an effective specimen thickness is used for the KQ evaluation, and the J-type load-line cutouts appear to have no effect on the measured KQ results.
Using Microwave Measurements to Detect Moisture in Asphaltic Concrete
Authors: Al-Qadi IL
Published: February 2009

An experimental technique based upon dielectric properties was developed to measure the volumetric moisture content in hot-mix asphalt concrete. The dielectric properties were calculated from the measured reflection coefficients and phase angles. The measurements were obtained over a band of frequencies in the microwave range of 12.4 to 18.0 GHz. The test program included different aggregate types, aggregate gradations, asphalt types, asphalt contents, air void contents, specimen thickness, and surface smoothness. Microwave reflection measurements were obtained for the hot-mix asphalt concrete specimens and their components in a sweep mode over the above frequency band. These measurements were analyzed, and the magnitude of the dielectric constant and the loss factor were calculated. The dielectric properties for these mixes were obtained at the dry state and at two levels of moisture content. The dielectric properties were correlated to the mix characteristics. Regression models were developed to predict the volumetric moisture content of hotmix asphalt concrete. A model developed from a theoretical approach was found to give the best correlation.
Load-Slip Behavior of Nailed Joints in Seven Amazonian Hardwoods
Authors: Pellicane PJ , Sá Ribeiro RA
Published: February 2009

Two hundred ninety-two nailed joints in seven species of Amazonian hardwoods were tested to evaluate their load-slip (P-Δ) behavior when subjected to lateral loading. The seven species commonly used in Brazilian light-frame construction had a range of specific gravities from 0.36 to 0.85 (based on an oven-dry volume) Four sizes of common wire nails were used to construct joints with main and side members of the same species.

From these tests, embedding strength values associated with a 5% offset load were obtained from the experimental (P-Δ) curves and equations derived from the European Yield Theory. The results suggest that the behavior of nailed joints made with tropical hardwoods is similar to that found in temperate zone species. Wood moisture content, in the range studied, did not meaningfully affect joint P-Δ behavior. In addition, embedding strength was influenced by the specific gravity of the connected material. However, no species effect was observable between species of similar specific gravity. Finally, an effect of nail diameter on embedding strength was seen; however, the lack of homogeneity of test materials precluded the accurate prediction of this effect.

Since the embedding strength data demonstrated some degree of positive skewness, three commonly used statistical distributions (log-normal, three-parameter Weibull, and Johnson's SB) were evaluated to quantify the variability of this parameter. All three distributions were excellent descriptors of behavior. Therefore any of these mathematical models would be a rational choice for representing embedding strength.
Development of a B4C/Al Cermet for Use as an Improved Structural Neutron Absorber
Authors: Beidler CJ , Hauth WE , Goel A
Published: February 2009

An aluminum and boron carbide cermet was evaluated for possible application as a neutron absorbing material where structural strength and rigidity will be required. The boron carbide/aluminum composite possessed unique continuous interconnected ceramic and metal phases. Traditional bocon containing neutron absorbing materials have relied upon dispersions of particles in metal or polymeric matrices. The dispersion of boron carbide particles placed restrictions on the B10 concentration, introduced areal inhomogeneities, and necessitated the use of cladding to achieve desired strength. Utilization of two continuous phases allowed for considerable strength properties without having to include cladding. Boron concentrations in excess of 60 v/o were obtained in the cermet, a level that only hot pressing could surpass. Also, the boron carbide particle distribution could be adjusted to optimize strength and/or improve homogeneity of B10 within the material.

A material with these characteristics will be ideal for demanding applications such as shipping casks and storage racks. The higher boron content provides for improved areal densities, thus reducing the shielding volume. Space can be conserved without sacrificing structural strength. This material can be fabricated in plates ranging in thickness from 0.076 to over 2.540 cm. Curved or complex shapes are also possible. The cost of this cermet can be expected to be much lower than hot-pressed boron carbide material.

The evaluation was made on the basis of physical performance of the boron carbide/aluminum cermet. Properties were measured over a range of loadings and particle distributions of the boron carbide. A semi-guided bend test was performed on 0.254 cm thick plates to measure the ability of the cermet to withstand deformation. The B10 density was measured by neutron attenuation methods.
High Effectiveness Shielding Materials and Optimal Shield Design
Authors: Greenspan E
Published: February 2009

A preliminary investigation of the effectiveness of new composite materials under development for shielding against neutrons and photons is reported upon. These materials are made from a proper mix of powders of tungsten, titanium or zirconium hydride and boron carbide, all bonded by hydrogenous materials such as polyethylene or silicone based materials. The investigation is carried out with the aid of the shield optimization code SWAN by considering a simplified 40-cm-thick spherical shield with CI-252 source at its center. The shielding ability of the new, so-called polynated and siliconated, materials is found to be highly superior to that of shielding materials in common use. The flexibility in tailoring the mix of inelastic scatterers, elastic scatterers, neutron absorbers, and photon attenuators to one's shielding needs, along with the information on material effectiveness functions which can be calculated with a code such as SWAN, are expected to enable improvements in future shield designs.
Properties of High-Density Concrete
Authors: Mukherjee PK
Published: February 2009

High-density concrete is used extensively in nuclear power plants for radiation shielding against biological hazards. Apart from the basic physical properties (i.e., compressive strength, density, and absorption), knowledge of thermal properties of such concrete is required to access its performance under service conditions. This paper describes investigative work carried out on a high-density concrete. Also, because aggregates are the most important and critical component of the high-density concrete, properties of the aggregates and the criteria for their use in concrete have been discussed. In addition, cores were obtained from a shielding wall of a 20-year-old nuclear plant and selective tests were carried out on the core samples for comparison. The mix proportions of the concrete from the wall were different from those of the laboratory-made concrete. Thermal properties, such as conductivity, diffusivity, specific heat, emissivity and coefficient of thermal expansion, were determined, and the values were compared with a normal-density dolomitic-limestone based concrete.
Shield Verification Testing at the Idaho Chemical Processing Plant — Fuel Processing Facility
Authors: Oswald AJ
Published: February 2009

A Shield Testing Program is being conducted at a new nuclear facility to verify that shield walls, doors, and windows meet the design criteria for radiation attenuation. A modified Teletherapy Unit is being utilized as a test unit. This unit has been successfully used for shield testing during the construction of two other major facilities. A collimated beam from a Co60 source is exposed on one side of the shield being tested, and the attenuated radiation is measured with a standard radiation detector. Detailed documentation is completed for each area tested. Detailed procedures are required for operation of the test unit. No significant personnel exposure has been recorded during any of the shield testing.

The Co60 test method is a known, proven technique that provides the required penetration and the capability to cover relatively large areas with a single exposure.
An Efficient Algorithm to Characterize Stress-Strain Data Using Piecewise Linear Curves
Authors: Vizzini AJ
Published: February 2009

An efficient algorithm to characterize experimental stress-strain data is preacated. The algorithm segments the curve into regions by locating regions with a maximum correlation coefficient. Thus the algorithm determines the initial region of the curve to be considered in determining the initial slope or, in the case of a stress versus strain curve, the initial modulus. The algorithm is of particular use in analyzing the elastic behavior of composites where nonlinear stress-strain, knees, damage, and other abnormalities may occur. The results of the algorithm are compared to linear regions determined from calculations of correlation coefficients involving all possible regions within a data file. In general, the algorithm provides the same linear regions as are determiend from the complete calulation of correlation coefficients and is at least one order of magnitude faster.
The Use of Small Punch (Bulge) Tests to Estimate Fracture Stress in the Lower Shelf Regime
Authors: Joo Y-H , Hashida T , Takahashi H , Shimomura K
Published: February 2009

The small punch fracture stress σf(SP) and fracture toughness KIc of embrittled turbine rotor steels have been evaluated at temperatures corresponding to the lower shelf regime. The lower bound values of σf(SP), determined by statistically analyzing the data, are found to be relatively independent of test temperature range from −196 to −170°C for rotor M steel and from −196 to −150°C for rotor T steel. The relationship of σf(SP) to fractographic features was also investigated. The lower bound values of σf(SP) were found to be comparable with values of the microscopic fracture stress σ*f. This result indicates that small punch tests might be used successfully to measure σ*f of materials at lower shelf temperatures.
On the Intrinsic Character of the Stress-Strain Curve of a Prestressing Steel
Authors: Toribio J
Published: February 2009

This paper deals with the influence on the stress-strain curve of a prestressing steel of such mechanical variables as the gage length, the sample length, and the gripping conditions. An original experimental technique was developed, both to increase the gage length of the standard extensometer and to test large size wires, using different grips. The results show that, at least in a first approach, the stress-strain curve of a prestressing steel has an intrinsic character. Nevertheless, small variations in the yield strength and the flow step were noticed when the sample length changed. These differences may be attributed to the initial curvature of the wire supplied in rolls.
A Method for Estimation of the Radius of Elastic-Plastic Boundary Around Cold-Worked Holes
Authors: Arora PR , Dattaguru B , Subramánya Hande HS
Published: February 2009

The radius of an elastic-plastic boundary was measured by the strain gage method around the cold-worked region in L72-aluminum alloy. The relative radial expansion was varied from 2.5 to 6.5% during the cold-working process using mandrel and split sleeve. The existing theoretical studies in this area are reviewed. The experimental results are compared with existing experimental data of various investigators and with various theoretical formulations. A model is developed to predict the radius of elastic-plastic boundary, and the model is assessed by comparing with the present experiments.
Analysis of Elastic and Plastic Strains for Internally Pressurized Cylinders
Authors: Gasiak G
Published: February 2009

Methods of theoretical considerations and experiments on elastic and plastic strains in rotational internally pressurised shells with rigid bottoms are presented. The shells were treated as three-dimensional bodies, and the algorithms and programs for numerical analysis were worked out according to the finite-element method (FEM) and Prandtl-Reuss theory of plastic flow. The presented methods of experiments were used for measurements of elastic and plastic strains in thin-walled rotational shells. Loading in the shell was incrementally realized. With the applied methods of numerical calculations and experiments, it is possible to analyze the bulging process in the shell up to the loss of strain stability. Strain increments are not limited in any way. The paper shows the results obtained with the shell bulging. A good agreement between the results obtained with FEM and those from experiments can be observed. The presented analysis can be a basis for work on a method allowing the control of the wall thickness while forming tubular elements in industry.
Drop Heights Encountered in the United Parcel Service Small Parcel Environment in the United States
Authors: Singh SP , Voss T
Published: February 2009

Packaged goods move through varieous logistical networks each day all over the world. Packages moving through these various networks are exposed to dynamic forces such as drops, tosses, and kicks. This study investigated the effect of drops, tosses, and kicks encountered in the United Parcel Service (UPS) small parcel environment in the United States. The effect of the weight and volume of packages shipped was studied.

The results of this study showed the highest drop observed in the UPS environment in 35 roundtrips from Lansing, MI to Monterey, CA was 42.1 inches for the Small-size package. The size of the package had no significant effect on the drop heights. Lighter weight packages for the smaller size experienced higher drop heights. Weight in general also did not have a significant effect on the Medium and Larger size package drop heights. 95% of the drops occurred at 30 inches for the Small/Light package, 24 inches for the Small/Medium package, 18 inches for the Medium/Light package, 24 inches for the Medium/Medium packages, 26 inches for the Medium/Heavy package, and 18 inches for the Large/Medium and Large/Heavy packages.
Effects of Notch Length on the Ductile Fracture of a Center-Notched Low Carbon Steel Plate
Authors: Makabe C , Kaneshiro H
Published: February 2009

Ductile fracture of a thin-notched specimen deformed to plastic collapse was investigated by observing crack growth on the specimen surface. A correlation between the ductile crack growth and the initial notch length was obtained. It was found that: (1) the crack growth rate, da/dε, for the strain increment depends on the crack length, a, and the nondimensionalized crack growth rate, (da/dε)/a, is faster for short notch lengths; (2) crack opening displacement, δ, measured in the vicinity of the crack tip was also dependent on the crack length and the notch length; (3) the crack opening rate, dδ/da, was inversely proportional to the crack length. Thus, the variation of crack opening displacement was found to have a good correlation with the crack growth rate.
An Experimental Appraisal of the Load-Deformation Properties of A325 High-Strength Bolts
Authors: Salih N , Smith J , Aktan HM , Usmen M
Published: February 2009

Current specifications and testing procedures of high-strength bolts are based on the results of early research performed in the late 1950s and the early 1960s using the testing technology available at that time. Within the past few decades, the development of new, advanced testing equipment and computerized data acquisition systems has brought about significantly improved capabilities for materials testing. In light of these advancements, conducting a new set of bolt tests was considered essential in appraising the load deformation properties of high-strength bolts using the new testing technology. In this study, samples of randomly obtained A325 high-strength bolts were tested in accordance with the ASTM standard test methods, utilizing a servo controlled universal testing machine and a computerized data acquisition system. This equipment differs from that used in the early research in the accuracy of the data collected and the existence of many available options for specimen loading. The new testing technology provides an easy determination of the yield point, the proof load, and ductility of the bolts. The study aimed at experimentally determining the load-deformation properties of high-strength bolts and comparing them with those generated by early research. The proof load, the yield strength, and the teasile strength obtained were much higher than the specified ASTM and AISC values. Additional studies were pursued to gain an improved understanding of the behavior of the bolts as affected by the exposed thread length in the grip. The tested bolts showed higher strength and lower ductility as the number of the thread exposed in the grip length decreased.
Superposition Theory Applied to Nail/Glue Joints in Wood: Part II—Stiffness Behavior
Authors: Pellicane PJ
Published: February 2009

A model based on concepts involving nonlinear superposition of nail and glue joint characteristics was examined to predict the load-slip (P-Δ) behavior of nail joints with elastomeric construction adhesives (nail/glue) in wood subjected to lateral loading. Four combinations of two wood species (lodgepole pine and hard maple) and two nail sizes (6d and 8d) were explored. One brand of commercially-available elastomeric construction adhesive was used. One-hundred-sixty-nine nail, glue, and nail/glue joints were tested to evaluate the P-Δ curve from the origin to 0.08125 in. (2.1 mm) slip. Theoretical predictions based on nail and glue joint stiffness were compared with experimental data from nail/glue joint tests. The results showed that the presence of glue used in conjunction with nails proved to substantially increase joint stiffness. Increases in joint stiffness from 25 to 100% per square inch (645 mm2) of bonded surface over the stiffness of joints without glue were realized. The superposition model proved to be a reasonable predictor of nail/glue joint stiffness at levels of slip not exceeding 0.03 in. (0.762 mm). For slip levels greater than 0.03 in., superposition consistently underpredicted (conservatively) joint stiffness for all four combinations of nail size and wood species studied. Therefore, superposition has been shown to be an accurate predictor of joint stiffness in the range of slip values from which allowable loads are determined in the allowable stress and draft reliability-based design codes.
Measurement of Thermal Conductivity of Refractory Bricks by the Nonsteady State Hot-Wire Method Using Differential Platinum Resistance Thermometry
Authors: Sengupta K , Das R , Banerjee G
Published: February 2009

An apparatus for measuring thermal conductivity of refractory bricks has been designed using the parallel hot-wire technique and differential platinum thermometry. The equipment has been found to be simpler and less expensive than the thermocomple-based apparatus available commercially. It has shown better reproducibility and proved its applicability for both the low- and high-density refractory types and also for temperatures up to 1250°C.
Application of Electro-Optic Sensor and Force Transducer on Leak Detection
Authors: Manesh AAI , Swaney MH , Saunders R
Published: February 2009

The application of the Electro-Optic Sensor and Force transducer on leak detection began with reviewing various leak testing technologies and their associated problems. Specific applications of differential pressure sensors for leak testing are discussed and the specifications of the University of Arkansas Electro-Optic Sensor and Force Transducer are explained. A design for a new differential pressure transducer based on the University of Arkansas Electro-Optic is presented. A leak tester was assembled by using a prototype of a differential pressure transducer. The performance test and calibration of the unit was accomplished by using a standard calibrated leak. The calibration results were then used to estimate the leak rate of some unknown samples. In order to reduce the ambient effect, a balance volume was attached to the reference chamber. In conclusion, a discussion of the problems and limitations is presented.
Laboratory Wheel Tracking Apparatus for Bituminous Pavement Studies
Authors: Tan S-A , Fwa T-F , Low B-H
Published: February 2009

Rutting deformation is one of the most common forms of pavement distress found on bituminous pavements, especially in the hot, tropical climate of Singapore. These deformations are usually found in the wheel track on roads carrying heavy, slow moving, channeled traffic, such as in the city and industrial areas at traffic light junctions. To and our investigation into the nature of pavement rutting, a laboratory wheel-tracking apparatus was used to simulate channeled wheel traffic loading under controlled conditions. It was upgraded with automated temperature and rut profile measurement capability. This article describes the features of the apparatus, which include temperature control of test specimens from ambient (27°C) to 70°C via a water bath with an adjustable weir, speed control of 0 to 80 wheel passes per minute, and variable wheel loading from 18 to 54 kg giving approximate equivalent tire pressures of 175 to 530 kPa. The apparatus can be used to simultaneously test three standard specimens of dimensions 405 mm by 135 mm by 90 mm-thickness. Single tests of two other sizes, which are two or three times the width of the standard specimen, are permissible. The rut depths are monitored by means of three linear variable displacement transducers (LVDTs), which measure the vertical displacements of each of the three wheel axles independently as rutting progresses. Due to errors induced by machine vibrations, accurate rut profile measurements can be made only under static conditions at selected intervals of wheel passes. With the use of a 200-ton-capacity static press, uniform dense asphaltic concrete beam specimens can be made, giving reasonably repeatable rutting test data on the apparatus, thus making it a valuable tool for evaluating the ratting potential of various mixes.
Jand CTOD Estimation Equations for Shallow Cracks in Single Edge Notch Bend Specimens
Authors: Kirk MT , Dodds RH
Published: February 2009

Fracture toughness values determined using shallow cracked single edge notch bend. SE(B), specimens of structural thickness are useful for structural integrity assessments. However, testing standards have not yet incorporated formulas that permit evaluation of J and CTOD for shallow cracks from experimentally measured quantities (i.e., load, crack mouth opening displacement (CMOD), and load line displacement (LLD)). Results from two-dimensional plane strain finite element analyses are used to develop J and CTOD estimation strategies appropriate for application to both shallow and deep crack SE(B) specimens. Crack depth to specimen width (a/W) ratios between 0.05 and 0.70 are modeled using Ramberg-Osgood strain hardening exponents (n) between 4 and 50. The estimation formulas divide J and CTOD into small scale yielding (SSY) and large scale yielding (LSY) components. For each case, the SSY component is determined by the linear elastic stress intensity factor. Kf. The formulas differ in evaluation of the LSY component. The techniques considered include: estimating J or CTOD from plastic work based on load line displacement (Apl∣CMOD), from the area under a load versus plastic crack mouth opening displacement diagram (Apl∣CMOD), and from the plastic component of crack mouth opening displacement (CMODpl). Apl∣CMOD provides the most accurate J estimation possible. The finite element results for all conditions investigated fall within 9% of the following formula. J=K2(1−v2)F+ηJ−CBbApl∣CMOD whereηJ−C=3.785−3.101aW+2.018(aW)2 The insensitivity of ηJ−C to strain hardening permits J estimation for any material with equal accuracy. Further, estimating J from CMOD rather than LLD eliminates the need to measure LLD, thus simphfying the test procedure. Alternate estimates of J and CTOD from measured plastic areas have equivalent accuracy to this formula; however, the η coefficients in these equations depend on the strain hardening coefficient. CTOD estimates based on scalar proportionality of CTODlsy, and CMODpl, such as that used in ASTM E 1290, Test Method for Crack-Tip Opening Displacement (CTOD) Fracture Toughness Measurement, are highly inaccurate especially for materials with considerable strain hardening.
Initiation and Stable Crack Growth Behavior of API X70 Steel at Low Temperatures (25°C ≥ T ≥ −95°C)
Authors: Romilly DP
Published: February 2009

Small-scale tests employing single edge notch bend (SENB) specimens of API X70 pipeline steel were conducted to assess the initiation and stable growth behavior of this material at test temperatures between 25°C and −95°C. Material resistance curves were generated based on various proposed J-integral and crack tip opening displacement (CTOD) relationships and criteria for defining crack initiation and stable growth. DC potential drop crack growth monitoring was employed to provide crack propagation data for development of the resistance curves. The temperature dependence of crack initiation and stable growth properties of this material are quantified and presented. Verification of the temperature independence of the normalized J or CTOD tearing modulus is also provided.
Determining Paint Adhesion to Wood Using a Uniform Double-Cantilever Beam Technique
Authors: Knaebe M , Williams RS
Published: February 2009

Accurately predicting paint adhesion without the lengthy time required for typical exposure and evaluation is advantageous. Mechanical tests that use shear block, lap shear, or tensile specimens to measure paint adhesion result in large data variability, making it difficult to differentiate subtle changes in adhesive strength. The objective of this study was to decrease the variability of measured paint adhesion in fracture toughness tests. Preliminary and computer-aided experiments were conducted using uniform double-cantilever beam (UDCB) and shear block specimens. The coefficient of variation (COV) for the shear block tests was about 15%. The UDCB specimens cut from the same panels as the shear block specimens had a COV of 10%. Computer-aided tests of UDCB specimens gave a COV of less than 5%. Results show that using UDCB specimens with the aid of a computer is an excellent technique for determining paint adhesion to wood.
Compressibility Analysis of Wet Abraded Woven Fabrics
Authors: Ukponmwan JO
Published: February 2009

This paper is concerned with the effect of abrasion on the compressional properties of different woves textile fabrics. The abrasive wear was induced using an Accelerator under wet and damp conditions and measured via mass loss. The compressional properties, i.e., compression and compressibility, were determined under comparable experimental conditions on an Instron Tensile Tester. Changes in the compressional properties of the fabrics caused by increments of pressure in the Instron were noted. The relationship between the compressional properties and such physical properties as mass, thickness, density, and specific volume of the fabrics before abrasion is also reported. The damp-abraded fabrics showed higher percentage increase or decrease difference in fabric compressional properties at given incremeats of pressure than the wet-abraded fabrics when compared to the unabraded fabrics.
Accurate and Precise Fabrication of Iosipescu Shear Test Specimens
Authors: Blackketter DM , Odom EM
Published: February 2009

The experimental measurement of the shear modulus and shear strength has been of special interest to the materials and composites community for a number years. In recent years, the Iosipescu shear test method has become popular and widely used. The most widely used test fixture is the Modified Wyoming test fixture which requires a specific and accurately fabricated specimen. To date, the methodology to fabricate and inspect these specimens has been left to the discretion of the individual investigators. This technical note presents a suggested methodology for the accurate and precise fabrication of Iosipescu shear test specimens. Dimensional data and the associated error from specimens fabricated are presented as verification of the methodology.
Loss Energy of Composite Materials. Part II: Impact Loading
Authors: Bledzki AK , Gassan J , Kessler A
Published: February 2009

This paper deals with the influence of material structure parameters (fiber treatment and content of micropores) on the impact behavior of composite materials. Furthermore, an impact falling-weight testing device and the characteristic impact values are introduced.

The role of the fiber/matrix interphase was investigated by using glass and natural (jute) fibers with different treatments. To study the influence of the content of micropores, epoxy foam reinforced with glass fiber mats were prepared. All materials were impacted on an instrumented low-velocity non-penetration falling-weight impact tester. By integrating the measured force/deflection curves, all characteristic values were determined. Finally, the fatigue behavior of epoxy foam reinforced with pre-treated woven fabrics and the jute/PP laminates under repeated impact were investigated. In all impact experiments, the damping index responded more sensitively to changes in the material structure than did the loss energy. Furthermore, it was found that the damping index is an excellent measurement for characterizing the extent of damage.
Modeling Considerations in Wood-Related Research
Authors: Pellicane PJ
Published: February 2009

It has been the author's experience that researchers will routinely use linear models to describe the relationships between correlated variables when that approach to modeling may not be the most rational. This article illustrates some of the circumstances when linear modeling is and is not the most viable alternative in characterizing the relationship between correlated variables.

In this study, several data sets are examined to illustrate how amenable they are to linear modeling. One data set selected shows a nearly ideal example of when linear least-squares regression is a realistic descriptor of the relationship between correlated variables. A second data set shows how material idiosyncrasies, such as species, size, or grade effects, can result in misleading models for parameter prediction. A third data set illustrates a more subtle inhomogeneity that is frequently found in experimental data involving tests of clear wood. When the relationship between correlated variables changes due to a shifting failure mechanism, a presumed linear relationship may misrepresent the relationship between variables in a large portion of the domain. It is the intent of this paper to remind or make researchers aware of the subtle characteristics of data sets that can influence modeling results.

One possible mechanism for modeling nonlinearly related variables (the univariate SB and the bivariate SBB distribution) is offered for consideration. This model has the unique feature of quantifying, in an analytic, closed-form fashion, the probability of a predicted variable for any value of the domain. In addition, when certain input values used to calculate SBB bivariate distribution parameters are defined correctly, convergence to the clear wood strength of a material or product is achieved.
Stress-Strain Behavior of a Fe-Ni-Cr Alloy During In-and Out-of-Phase Synchronized Thermal Cycling and Mechanical Cycling Tests
Authors: He Q , Bressers J , Fenske E , Decat R
Published: February 2009

The stress-strain behavior of a Fe-Ni-Cr alloy during in-phase and out-of-phase tests under conditions synchronizing thermal cycling with mechanical cycling has been studied by using a specially designed thermal cycling unit. The curves of cycling stress, strain, and temperature versus time indicate that the thermomechanical cycling softening phenomenon occurring in the higher-temperature region, close to the maximum thermal cycling temperature, is a common characteristic under thermomechanical cycling in-phase and out-of-phase superposition tests. However, a difference in behavior between in-phase and out-of-phase is evident. The tests show that the thermomechanical cycling softening occurred in the tensile strain range for in-phase testing and occurred in the compressive strain range for out-of-phase.
Repeatability and Reproducibility in Walkway-Safety Tribometry: Abrasive-Grit Size in Test-Foot Preparation
Authors: Fendley A , Marpet MI , Medoff H , Schutter D
Published: February 2009

To reduce slips and falls there is a need for repeatable and reproducible measurement, under both field and laboratory conditions, of the slip resistance between pedestrian shoe bottoms and the surfaces involved in human locomotion. Improvement of repeatability (within laboratory) and reproducibility (between laboratories) of portable tribometer test results should be a goal of tribometer designers.

This paper reviews the background of advances in friction-related knowledge applicable to improving the repeatability and reproducibility in walkway-safety tribometry. It explores the use of the scanning electron microscope and the coherent-light profilometer to define morphological differences between Neolite® Test Liner and Standard Leather test feet sanded with two different abrasive-paper grits and worn shoe-bottom surfaces composed of the same materials. The experimental method and results are discussed, as is the significance of the findings. Also discussed is the issue of abrasive-paper grit size and its effect on tribometric test results. The paper suggests directions for further research.
Precision in the Extrapolation of Creep Rupture Data
Authors: Sandström R , Lindé L
Published: February 2009

To be able to determine the accuracy in the extrapolation of creep rupture data, expressions for estimating the error are presented. One expression is based on the statistical uncertainty in the least square fit to the data. This estimate can be considered as the minimum possible error that is present in extrapolated values. Expressions for the upper limit of the error based on linear as well as higher-order polynomials are derived. It is demonstrated that the expression based on linear extrapolation has a general applicability and covers most cases of technical interest. Comparison to previously performed extrapolation analyses shows that the actual variation between extrapolation methods lies in general between the least square error and the upper limit estimate. It is proposed that design values derived from extrapolated creep rupture data should be reduced, with an additional data factor if the estimated error in the extrapolation is larger than what is typical in the materials codes and standards. Values for these data factors are given.
Ability of a Viral Penetration Test (ASTM F1671-95) to Detect Small Holes
Authors: Lytle CD , Baker KH
Published: February 2009

A modified version of ASTM Test Method F167195, Test Method for Resistance of Materials Used in Protective Clothing to Penetration by Blood-Borne Pathogens Using Phi-X174 Bacteriophage Penetration as a Test System, was characterized using as test material pieces of condom latex with laser-drilled holes of known size. The modified test included the initial 5-min, no-pressure period together with the 1-min, 2-psi period, but eliminated the final 54-min, no-pressure period. Virus penetration was detected for all holes with diameters above 1.0 µm. The quantitative results were in good agreement with calculated fluid flow through a cylinder (Poiseuille equation) for holes above 2 µm. A brief argument is presented suggesting that the final 54-min period at no pressure be eliminated from the test protocol.
Effect of Construction Adhesive and Joist Variability on the Deflection Behavior of Industrial Wood Floors
Authors: Pellicane PJ , Robinson G
Published: February 2009

A total of 19 440 structural floors of a geometry and material configuration consistent with those used in industrial construction in North America were numerically analyzed to determine their deflection characteristics under a constant uniformly distributed load of 145 lbf/ft2 (215 Pa). The intent of these analyses was to determine the effect of joist modulus of elasticity (MOE) (mean and variability) on the deflection behavior of industrial floors (made with glue-laminated (glulam) structural members covered by plywood sheathing) and to quantify the contribution of elastomeric construction adhesives (ECA) in reducing the deflection of such systems. The joist 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 joist variability (at each MOE value) varied between coefficient of variation (COV) values of 0.025 to 0.150 in increments of 0.025. One hundred-eighty floors were evaluated at each mean MOE value and COV value for the joists. MOE values for each of the eleven joists in each floor were obtained via a statistical simulation process. All other sheathing and connector properties [nail slip modulus = 25 500 lbf/in. (4466 N/mm)] remained constant. After the 180 floors were analyzed using only nailed connections between joist and sheathing, new random numbers were simulated (with the same mean and standard deviation) to produce 180 new floors for analysis with increased connection stiffness to reflect the contribution of the ECA used with the nails to attach sheathing to joists.

The results indicated that ECA used with nails contributes positively to floor system stiffness. The magnitude of the contribution of 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 deflections. Reductions of nearly 6.3% were realized when the mean joist MOE was 1250 ksi. For floors made with stiffer joists (mean MOE = 3250 ksi), floor deflections were reduced by only about 3.3% when adhesive was used. The presence of ECA between joist and sheathing did not have much effect on reducing the variability of floor behavior. When components were connected only with nails, the COV of floor deflections varied between 0.01 and 0.09. When ECA were incorporated into the assembly, the COV of floor deflections had very much the same range.

It can be concluded that the presence of ECA can reduce the deflection of this particular industrial floor configuration by approximately 3.0 to 6.3% depending on joist stiffness.
A New Gripping Technique for Small Metal Specimens
Authors: La Van DA , Duncan PB , Zeng H , Sharpe WN
Published: February 2009

A new technique has been developed to grip small tension specimens. The specimens are 30.5 mm long with a test cross section that is 3.2 by 3.2 mm, and they have wedge-shaped ends that fit into matching slots in the grips. Alignment is accomplished by screws that position the specimen into the middle of the slots. Strain is measured with foil gages mounted front and back, and the specimen is tested in a medium-size servohydraulic test machine. The stress-strain curves of the small specimens agree well with those from standard-size specimens.

The objective was to develop a specimen to study the local behavior of inhomogeneous materials such as steel weldments. The specimen had to be small enough for the test section to contain material from one weld bead, yet large enough to be tested in a servohydraulic test machine using a standard load cell, grips, and strain gages.

There are two sub-size or small-size specimens described in ASTM E 8 and E 8M [1]. The sub-size rectangular specimen is 6.4 mm (1/4 in.) wide with a gage length of 25.4 mm (1 in.) and an overall length of 101.6 mm (4 in.). The smallest round specimen described has a diameter of 2.87 mm (0.113 in.), a gage length of 11.4 mm (0.450 in.), and an overall length of 32 mm (1.25 in.). While the test section of the round specimen is small enough, cutting and testing these from weld metal using standard techniques would be difficult. The size of the available weld specimen prevented the use of the sub-size rectangular specimen as it required too much extra material for gripping.
Leaching Studies on ASTM Type F Fly Ashes by an Accelerated Process Method
Authors: Pandian NS , Balasubramonian S
Published: February 2009

Among the various uses for fly ash, geotechnical application is one that offers scope for large-scale utilization. Due to its low unit weight, good frictional properties, and non-plastic nature, fly ash can be used effectively as a fill material in low-lying areas, as a backfill material, as an embankment material, etc. However, the possibility of toxic metals being leached out, leading to surface and/or groundwater contamination, has to be examined. This paper presents such an investigation carried out on two Indian fly ashes. The studies indicate that the pH of the solution plays an important role in the leaching behavior of fly ashes.