bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Detection of Welding Seam Parameters Based on Active Infrared Technology
Authors: Jiang J , Ding G , Yan G , Chen T , Gan X 
Published: February 2009

Abstract
How to rapidly and with high precision detect various parameters of welding seams, such as the width, length, and offset is a significant challenge. This article first studies the microstructures and chemical components of welding seams. Then we discuss the effects of different microstructures and chemical components on active infrared images. Through theoretical and experimental analyses, it is well known that active infrared technology can be applied in the investigation of welding seams. Through the adaptive lifting discrete wavelet transform and the simple algorithm of iterative segment, various parameters of welding seams are established. The method put forth in the article is rapid, of high precision, on-line in real time. The precision is up to 0.1 mm. It takes only 0.02 s to segment an active infrared image on a P-III 700 personal computer.
Test Devices for Strength Measurements of Bars Under Contact Loading
Authors: Fett T , Munz D , Thun G 
Published: February 2009

Abstract
Bars loaded by opposite concentrated forces via rollers are appropriate specimens for the determination of strength under contact loading. Measured multiaxial strength values are located in the second quadrant (σ1 &gt; 0, σ2 &lt; 0) of the biaxial failure diagram. In this paper stress solutions for the proposed strength specimens are provided. As practical applications of the proposed specimens, the strengths for two aluminas, an AIN, and a HPSN ceramic, were determined and compared with bending strength results.
Small Punch Testing in Creep Conditions
Authors: Dobeš F , Milička K 
Published: February 2009

Abstract
The creep behavior of low-alloy steel was studied using small punch tests under the action of constant force. Disks with a diameter of 8 mm and a thickness of 0.5 mm were pushed against a die with a bore of 4 mm diameter using a ball of 2.5 mm diameter. The time dependence of the central deflection was registered. The resulting dependence has the sigmoidal shape typical of conventional creep tests but with a very significant primary stage. The conventional constant-stress creep tests were performed for comparison. A simple method for the approximate correlation of the force in punch tests with the stress in conventional creep tests of the same duration is suggested.
Accurate Measurement of Flow Stress Curves at High Temperatures for Low Strain Ranges
Authors: Carmona R , Lacey AJ , Beynon JH , Sellars CM 
Published: February 2009

Abstract
The present paper reports a comparison of flow stresses obtained by tension, plane strain compression, and axisymmetric compression testing in different machines with or without extensometers in the gage length section. Flow stress curves obtained from different test systems suggest machine and specimen geometry dependence, when the strain is computed based on gross specimen deformation. Finite element simulations give some insight into the interpretation and use of each mechanical testing technique, revealing the distribution of the strain field in each case. The results show that careful calibration of every testing machine and, in some cases, finite element modeling of the tests, are essential to give a similar curve for the same nominal deformation conditions.
Laboratory and Field Evaluation of Piezoelectric Weigh-in-Motion Sensors
Authors: Papagiannakis AT , Johnston EC , Alavi S , Mactutis JA 
Published: February 2009

Abstract
This paper presents the results of the laboratory and field evaluation of the piezoelectric weigh-in-motion (WIM) sensors of two manufacturers, namely Vibracoax (VC) and Measurements Specialties Incorporated (MSI). The laboratory evaluation involved fatigue testing of two sensor types for each manufacturer, one factory-encapsulated and the other bare. The fatigue testing involved three contact stresses as well as dry and wet conditions. Significant sensor fatigue was experienced only under wet conditions. The field evaluation of these sensors was carried in both asphalt concrete (AC) and Portland concrete (PC) installations. The facilities at Nevada's WesTrack and at a CalTrans Heavy Vehicle Simulator site were used, respectively. All sensors exhibited high raw signal precision at any given time. Raw signal amplitude seemed to depend on temperature for the sensors installed in the AC pavement. For increasing pavement temperature, the raw signal amplitude of the VC sensors decreased, while that of the MSI sensors increased. The signal-to-noise ratio of the raw signal increased with increasing temperature for the sensors installed in the AC pavement. WIM load measurement precision and sensitivity to temperature varied between sensors. The poor load precision of some of the sensors was attributed to the load calculation algorithm in the WIM data acquisition system, rather than to sensor malfunctioning. During the period of the field tests, no consistent changes in WIM axle load measurements were observed that could be attributed to piezoelectric sensor fatigue.
Static and Dynamic Behavior of Damaged Concrete and Granite in Compression
Authors: Gomez JT , Shukla A 
Published: February 2009

Abstract
Static and dynamic compression experiments were performed on concrete and granite specimens with various levels of induced damage. Damage was induced into the specimens by repeated impacts from a falling weight and quantified as a measure of damage crack surface area per volume using a statistical microscopy technique. The static experiments were performed following ASTM standard procedures. The static compressive strength of both materials decreased with increasing levels of damage. The reduction in strength is due to the induced damage causing the activation and propagation of failure cracks in the specimens.
The dynamic experiments were conducted using a 50.5 mm diameter Split Hopkinson Pressure Bar. The undamaged dynamic compressive strengths of both the concrete and granite were approximately twice their static values at average strain rates of 380/s and 400/s, respectively. However, as the damage levels were increased, the dynamic compressive strength remained unchanged. For the dynamic experiments, the strain energy is stored in the specimen faster than the cracks can develop and coalesce to completely fail the specimen. Therefore, the relatively small amounts of induced damage did not affect the dynamic compressive strength.
On the Recovery Coefficient and Parameter Selection for a New Type of Disk Spring Pile Cap
Authors: Zhou L , Chen J , Zhou X 
Published: February 2009

Abstract
The use of the disk spring pile cap, consisting of a contained group of several stacked disks, because of its high spring constant and high recovery coefficient, can raise pile driving construction efficiency. In order to reach the optimum effect, however, the proper spring arrangement in the stack, the proper composite spring stiffness, and the proper spring recovery coefficient must be selected. The authors have carred out an optimization analysis of these disk spring parameters in order to find the most appropriate set for effective pile driving under given conditions.
Evaluation of a Boron-Nitrogen, Phosphate-Free Fire-Retardant Treatment. Part I. Testing of Douglas-Fir Plywood per ASTM Standard D 5516-96
Authors: Winandy JE , Richards MJ 
Published: February 2009

Abstract
The objective of this work was to evaluate (a) the effects of a new boron-nitrogen, phosphate-free fire-retardant (FR) formulation on the initial strength of Douglas-fir AB-grade plywood and (b) the potential of this FR treatment to experience subsequent thermal degradation inservice when exposed to elevated temperatures. Test Method ASTM D 5516 was generally followed. The results of our analysis indicated that treatment and post-treatment redrying with the new boron-nitrogen, phosphate-free FR had a significant negative effect of about 7% on bending strength and a significant negative effect of 26% on energy-related properties, such as work to maximum load. The properties of modulus of elasticity and maximum moment canying capacity were not significantly reduced. Our results indicate that the likelihood of FR-treated plywood to experience in-service reduction in mechanical properties when exposed to elevated temperatures is no different than that of matched untreated plywood. As a result of our analysis, we recommend a revision to the cutting procedure specified by D 5516-96. We recommend that users first cut the specimens, then inspect and cull specimens with defects, and finally allocate specimens to experimental groups prior to FR treatment and redrying. We also recommend the substitution of commercially available grades of higher quality plywood, such as AA or AB, for the custom-made N-grade plywood currently recommended by D 5516-96.
Comparison of Random and Partition Testing Considering the Test Profile
Authors: Zhang L , Luo X , Chen M 
Published: February 2009

Abstract
There has been much interest in the analysis of the effectiveness of partition and random testing. Investigators studied and compared these two strategies from different points of view and came to different conclusions. Some used the probability of detecting at least one failure to quantify the fault-detecting ability of a testing strategy. Some used the expected number of failures detected to assess them. But they did not consider the test profile. Differing from this early work, this paper compares random testing with partition testing by looking at three parameters: the confidence index, the upper confidence bound, and the total number of test cases, considering the test profile. Our results show that random testing generally performs better than partition testing and equally as well as partition testing when the operational profile coincides with the test profile. We also derive the formulas to calculate the three indexes for random and partitional testings.
Test of the Acquisition System in an Analog Gamma Camera
Authors: Besbes H , Bouhlel MS , Salah RB 
Published: February 2009

Abstract
The quality control of an analog gamma camera in our nuclear department concerns exclusively the detection head. To evaluate the acquisition system we use a test system composed of an output card and software called ASST. The test consists of transforming the digital data of a scintigraphic image into three analog signals similar to those delivered by the detection head. These signals are introduced into the acquisition system for reconstructing the image. The software ASST allows comparison between the original and the acquired image in order to evaluate the quality of acquisition.
A Comparison of the Performance Tests Used for Furniture Packaging
Authors: Connolly SM , Marcondes JA , Weigel TG , Lee A 
Published: February 2009

Abstract
ISTA Procedure 2C and two options in NMFCC Item 181, stacked vibration and compression and vibration in separate tests, were compared to determine the equivalency of common U.S. furniture packaging performance tests. Containers constructed of two different corrugated fiberboard specifications were evaluated; Box A: a 32 lb/in. (5.6 kN/m) ECT rated board with a basis weight combination of 35HP/26/35HP, and Box B: a 200 psi (1378.95 kPa) Mullen rated board with a basis weight combination of 42/26/42. Ten corrugated fiberboard containers of each board type were tested following each of the test protocols. After testing, the contents were removed and the residual compression force at failure and deflection at failure of the containers were measured. These data were compared to the compression force and deflection at failure of control samples for the two board grades tested.
Results showed that Item 181 Method A produced significantly different residual compression force at failure when compared to Item 181 Method B and Procedure 2C for both boxes. Item 181 Method B and Procedure 2C were not significantly different. Also, the two boxes showed significantly different residual compression force at failure results for each of the test protocols studied. The percent change in compression force at failure based on control samples, however, was not significantly different between the boxes studied.
Estimation of theCtParameter: Experimental Implications
Authors: Leung C-P , McDowell DL , Saxena A 
Published: February 2009

AbstractThis paper examines the evaluation and interpretation of the Ct parameter that has been proposed for correlating crack growth under non-steady-state creep conditions. The study has been carried out by finite element analysis of the commonly used compact-type fracture specimen with stationary cracks.It is shown that the loss of constraint of the creep zone growing at the crack tip region due to intense creep at the loading pins can have a significant effect on the results of the load line displacement rate which are used to calculate Ct. Since Ct is identical to C* under extensive creep conditions, these effects also seriously impact determination of other commonly used creep crack growth parameters. This study has given some insight into the proper care that should be taken in obtaining experimentally measured and numerically calculated load line displacement rates in fracture specimens so as to eliminate the undesired effects of intense creep at the loading pins and/or between the crack tip and loading pins. It is shown that compact-type specimens with a crack size to width ratio greater than 0.5 and loaded with a dead weight are best suited for obtaining creep crack growth rate data. A relationship between Ct and the crack tip opening displacement rate has also been derived that provides a more complete framework for the analytical and experimental evaluation of the Ct parameter.
Effect of Compressive Underloads and Tensile Overloads on Fatigue Damage Accumulation in 2024-T351 Aluminum
Authors: Pompetzki MA , Topper TH , DuQuesnay DL , Yu MT 
Published: February 2009

Abstract
Intermittent compressive underload and tensile overload tests were carried out on smooth specimens to determine the effect of large stress cycles on the fatigue damage of subsequent small cycles. A load interaction damage model, using a power-law relationship based on crack closure and damage concepts, accurately predicted the test results. The interaction damage was described by assuming that small fatigue cracks in smooth specimens have similar behavior to long cracks. The results indicate that small cycles below the constant amplitude fatigue limit can contribute significantly to damage accumulation, and that conservative damage summations can be made using a modified reference curve based on constant amplitude tests with a minimum stress on the order of the monotonic yield stress.
Bending Strength of Gray Cast Iron
Authors: Noguchi T 
Published: February 2009

Abstract
An experimental and theoretical study was made on the influence of the dimensions and geometry of cross sections on the bending strength of gray cast iron. The experiments revealed that the bending strength varies with specimen height, with higher bending strengths being recorded for smaller heights. This is explained by a region under the beam surface where the stress exceeds the tensile strength of the material. This overstressed depth is about 3 mm in 20 to 30 mm high beams and smaller in thinner beams.
The geometry dependence of bending strength is caused by non-linearity of the stress-strain curve. Numerical simulation by the fracture criterion with a constant overstressed depth showed that the bending strength of round bars is 10% higher than that of rectangular beams. In T cross sections, the influence of the section geometry is more marked. The experiments agreed well with the calculations.
Measurements of Dynamic Young's Modulus in Short Specimens with the PUCOT
Authors: Wickstrom SN , Wolfenden A 
Published: February 2009

Abstract
The piezoelectric ultrasonic composite oscillator technique (PUCOT) was used at frequencies in the range 40 to 150 kHz to measure dynamic Young's modulus for short-length single crystals of copper at temperatures in the range 25 to 650°C and for poly-crystalline copper at room temperature. Corrections to the modulus for variations in l/d (length/diameter) resulted in no loss of precision due to wave velocity dispersion.
Effect of Crystallographic Texture on Flexure Fatigue Properties of Ti-3Al-2.5V Hydraulic Tubing
Authors: Meredith SE , Schemel JH 
Published: February 2009

Abstract
Ti-3Al-2.5V alloy has long been known to have strong anisotropic mechanical properties due to its hexagonal crystal structure. Early workers discovered that tubing made from this alloy had enhanced fatigue resistance when crystals were oriented in a “radial” direction as opposed to the “tangential” direction. The focus of this current work was to test the impact of texture on flexure fatigue strength over a wide texture range and find if an optimum crystallographic texture existed for fatigue resistance. The results show that an optimum crystal orientation does indeed exist and that tubing with a texture either less radial or more radial displays lessened fatigue life.
The lessened fatigue life of highly radial tubing was previously unknown and is not well understood. The findings from this work should be considered by engineers when designing aerospace hydraulic systems and a texture range, not just a minimum, should be specified.
Measurement of Maximum Arrest Force in Performance Tests of Fall Protection Equipment
Authors: Sulowski AC , Brinkley JW 
Published: February 2009

Abstract
Frequency response characteristics for electronic measurement systems and mechanical test fixtures used in tests of fall protection equipment are proposed. The recommendations are based upon the analysis of the dynamic properties of the human body as measured in impact and vibration tests with volunteer subjects. The critical frequencies that are associated with human injury were found to be in the range of 0 to 16 Hz. A corner frequency of 100 Hz is recommended for the measurement system, and a minimum resonant frequency of 200 Hz is recommended for the mechanical test fixture.
Estimation of Characteristic Values of Fracture Toughness
Authors: Slatcher S 
Published: February 2009

AbstractIt is desirable in design codes to characterize material strength by a low fractile of its distribution. This low fractile is known as a characteristic value. The material strength variable considered here is fracture toughness.Ten realistic fracture toughness distributions were defined, and two characteristic values were estimated on the basis of simulated observations from these parent distributions. The estimates were then compared with the actual characteristic values to evaluate the quality of the estimators. Three estimators were evaluated: one estimator was based on the assumption that the parent distribution was log-normal; the second estimator assumed that it was a two-parameter Weibull distribution with a shape parameter equal to two; and the third was a power limit estimator, which assumed little about the parent distribution's parametric form.The results suggest that in practical situations the log-normal method gives the best estimator, and that ten is a reasonable number of fracture toughness tests for the purposes of characteristic value estimation by the log-normal method.
Cyclic Stress-Strain Behavior and Low Cycle Fatigue of Ti 6242
Authors: Bui-Quoc T , Gomuc R , Biron A , Nguyen HL , Tadros RN 
Published: February 2009

Abstract
Results of strain-controlled fatigue tests at 329°C on Ti 6242, a potentially important material for aircraft engines, are reported. These tests were carried out under completely reversed strain conditions (strain ratio Rε = −1.0) and with positive strains (Rε = 0.0). Comparisons are made between the stress-strain relations obtained from monotonic tensile tests, at fast and slow strain rates, and those obtained from constant strain amplitude fatigue tests and from increasing multistep fatigue tests. The influence of induced mean stress is discussed.
Relationships Between the Results of Nail Impact Bend Tests and Selected Nail Material Properties
Authors: White MS , McLain TE , Padla D 
Published: February 2009

Abstract
Selection criteria for nails vary significantly. Some fastener specifications contain criteria based on hardness tests; others are based on yield strength or the results of impact bend tests (MIBANT). Selection may also be based on the carbon content or SAE class of the nail wire. To assist the specifier in the nail selection process, the relationship was studied between the MIBANT angle, an apparent flexural yield strength, the hardness, and the carbon content of nails. Carbon content was found to have a small influence on the mechanical properties of non-hardened nails. Because of apparent variations in work hardening during wire drawing and nail manufacture, carbon content is not a reliable criterion for the selection of non-hardened steel nails. Conversely, carbon content significantly influences the properties of hardened steel nails when the steel carbon content is greater than 0.10%. MIBANT angle, Vickers hardness number, and flexural yield strength are highly correlated for lowcarbon steel nails. Empirical relationships between these properties are presented. MIBANT angle was found to be a better indicator of the flexural yield strength of nails than Vickers hardness number.
Instrumented Impactor for Testing Wood-Base Floor Panels
Authors: McNatt JD , Soltis LA 
Published: February 2009

Abstract
The current ASTM method for evaluating impact resistance (ASTM E 661), which uses a leather bag filled with 14 kg (30 lb) of lead shot, is adequate for comparative rating of panels. Our objective was to obtain a more precise measure of failure initiation. An instrumented steel impactor was developed to evaluate the impact resistance of single-layer wood-base floor panels. Panel materials evaluated were plywood, waferboard (two manufacturers), and oriented strandboard. All were nominally 19 mm (¾ in.) thick with tongue-and-groove edges and were approved for single-layer flooring. Impact resistance tests were conducted on the panels using a 14-kg (30-lb) lead-shot bag, a 14-kg (30-lb) steel impactor, and a 27-kg (60-lb) steel impactor. Floor panel damage was measured by the amount of energy absorbed by the panel, time to maximum deflection, and residual panel deflection (permanent set). The 14-kg (30-lb) impactor proved to be more precise for identifying damage initiation because the 27-kg (60-lb) impactor caused complete failure of some waferboard and oriented strandboard after only two or three drops. For all panel types, the 14-kg steel impactor caused 30 to 40% greater deflection than the 14-kg lead-shot bag for any given drop height.
Stress Intensity Factors for Side-Grooved Fracture Specimens
Authors: Macdonald BD , Pajot JJ 
Published: February 2009

Abstract
Analytical support was sought for using Freed and Krafft's concept of effective thickness, (BBN)1/2, in ASTM plane strain formulas for elastic stress intensity factor, K, for side-grooved fracture specimens. Three-dimensional, elastic, finite-element analysis of various smooth and 20% side-grooved specimens yielded K values which not only supported this idea but also showed it to be slightly conservative. This result was expected to be generally true for all elastic fracture specimens because the finite-element K calculation was based on the elastically singular Gauss point stresses right near the crack front. Constraint at these points was constant through the thickness and nearly equal to its plane strain value. This result was insensitive to the presence of side-grooves and applied to most of the specimen thickness just ahead of the crack. Therefore the use of (BBN)1/2 in K formulas was supported not only for the elastic portion of J-integral testing (ASTM E 813 and E 1152) but for plane strain fracture toughness testing (ASTM E 399).