bluuebunny/crossref_metadata_2025_split huggingface dataset:
Delayed Yielding of a Plane Stress Viscoelastic Dugdale Model
Authors: DasGupta A , Brinson HF 
Published: February 2009

Abstract
The purpose of this investigation is to characterize the delayed yielding and fracture phenomena in a viscoelastic ductile polymer where crack growth is associated with the formation and growth of a plastic zone at the tip of the crack. This investigation deals with the time before catastrophic failure occurs in front of the crack tip. The bulk material is considered viscoelastic as well as rate dependent and is modeled by a modified Bingham model used by Brinson. The yielded material in the crazed region is modeled by the viscoelastic-plastic model of Crochét. Our theoretical solution has been adapted to a plane stress polycarbonate Dugdale model to facilitate a simple experimental verification. Such results could be useful in predicting lifetime, reliability, and failure criteria in structural members made from viscoelastic-plastic materials.
A Mathematical Model for the Determination of the Breakage Distribution in Batch Grinding
Authors: Tomlinson PN , Venter RD , de Malherbe R , Lees L 
Published: February 2009

Abstract
A mathematical model analogous to the rate of decay of radioactive materials has been developed to describe the unit operation of comminution. The model provides a useful theoretical base from which the fraction by weight on screens of different sizes can be determined after defined periods of grinding.
Studies on the Characteristics of Erosion with Plain Jets and Jets with Cavitation Inducers
Authors: Syamala Rao BC , Janakiram KS 
Published: February 2009

AbstractExperimental investigations made on the characteristics of erosion resulting from the impingement of liquid jets is reported. Experiments were conducted for several plain jets of 4- to 12-mm diameter and jets with cavitation inducers of four diameter ratios in a velocity range of 5 to 45 m/s. A detailed dimensional analysis of the several parameters governing liquid impingement erosion is presented. The erosion rate-time curves for impingement by jets with cavitation inducers did not show the incubation and accumulation zones significantly. The normalized erosion rate increased with jet velocity and approached a constant value at higher jet velocities. The erosion rate decreased rapidly and then remained approximately constant with an increase in caviation number. The erosion rate increased faster with frequency of impingement than with increase in jet velocity. A maximum value in peak erosion rate occurred around angles of impingement of 25 to 40 deg.
Development of Light- and Water-Exposure Apparatus
Authors: Suga S 
Published: February 2009

Abstract
Several developments designed to solve the problems found in the operation of light- and water-exposure apparatus of enclosed carbon arc type, open flame carbon arc type, and xenon arc type are described. The life of carbon rods was lengthened from 20 to 48 h in an enclosed carbon arc lamp and from 20 to 60 h in an open flame carbon arc lamp. In a xenon lamp the rate of the decrease in radiation output was reduced, doubling the life of the lamp. An automatic system for light intensity control in a xenon arc maintained a constant level of intensity throughout the test period, and an automatic system for black-panel temperature control made it possible to minimize the variation of temperature to within ±1°C. These developments increase the usefulness in operational procedure and improve the reproducibility of the test.
Fracture Toughness of Stretched Acrylic Plastic
Authors: Sutton SA 
Published: February 2009

AbstractThis paper presents the method and results of a parametric study of instability toughness, as measured by the plane-strain KIc and plane-stress Kc fracture toughness of a multiaxially stretched acrylic plastic. A large number of computer-controlled tests were conducted with the compact tension specimen under high compliance loading/load control. These tests reveal the significant effects on Kc and KIc of a wide range of loading rates, specimen thicknesses, and specimen geometry. A direct and immediate application of the results is the recommendation of a new fracture toughness acceptance test for these materials.
The “Instantaneous” Effect of Internal Moisture Conditions on the Strength of Glass-Fiber-Reinforced Plastics
Authors: Ishai O , Arnon U 
Published: February 2009

Abstract
Glass-fiber-reinforced laminates composed of two different commercial epoxy resin matrix formulations, a “medium-temperature” system and a “high-temperature” system, were tested in tension after immersion in hot water. Tests were carried out both in the “as-is” wet condition and after drying. The internal moisture condition was found to have a significant effect on the tensile strength. Dried specimens of the medium-temperature resin were stronger than their wet counterparts. The reverse was the case with specimens based on the high-temperature resin.
A Composite Grip Design for Elimination of Extraneous Noise During Acoustic Emission Testing
Authors: Wood WE , Dilipkumar DD 
Published: February 2009

Abstract
A major problem in acoustic emission analysis during dynamic loading is the noise generated by the test system itself. A composite grip assembly, designed on the principle of rapid attenuation of sound waves when they pass through multiple interfaces, can reduce the background noise by almost two orders of magnitude. This allows a maximum amount of information to be obtained through acoustic emission analysis.
Infrared Techniques for the Evaluation of Silicon Carbide Heat-Exchanger Tubing
Authors: Deininger WD , Kupperman DS 
Published: February 2009

Abstract
The potential application of infrared techniques to detect flaws and measure heat transport in silicon carbide heat-exchanger tubing is discussed. Axial heat-flow patterns were monitored with a commercially available infrared camera. Computer modeling was used to help establish the relationship between temperature distributions and the various thermal parameters. The experimental data and computer-modeling predictions were in fair agreement. These tests indicated that thermography may be a useful nondestructive-evaluation technique for rapid assessment of thermal-heat-transport properties in silicon carbide heat-exchanger tubing.
Constant-Pressure Liquid Filtration: Mathematical Models for Fast Plugging of the Filter Medium
Authors: Johnston PR , Beals DL 
Published: February 2009

Abstract
While four different, classical, mathematical expressions exist to describe the rate at which flow decreases during constant-pressure, liquid filtration, none describes the situation in which the flow rate drops very fast, such as in rapidly plugging operations. Presented here are three additional expressions which do.
Effects of Stress Ratio on Fatigue Crack Growth Rates in X70 Pipeline Steel in Air and Saltwater
Authors: Vosikovsky O 
Published: February 2009

AbstractFatigue crack growth rates in an X70 pipeline steel were measured over a wide range of stress intensities in laboratory air and in 3.5% sodium chloride solution under free corrosion and cathodic (coupled to zinc) potentials. The effects of stress ratio in all these environments and of cyclic frequency in the sodium chloride solution were studied. The results are compared with fatigue crack growth rates measured previously in lower strength X65 steel. The stress ratio strongly influences the fatigue crack growth thresholds and close-to-threshold growth rates. With increasing stress intensity range, the stress ratio effect decreases similarly in both air and aqueous environments. The lower cyclic frequency enhances corrosion fatigue crack growth rates at intermediate stress intensity ranges, as was observed earlier in X65 steel.
Performance of Chevron-Notch Short Bar Specimen in Determining the Fracture Toughness of Silicon Nitride and Aluminum Oxide
Authors: Munz D , Bubsey RT , Shannon JL 
Published: February 2009

Abstract
Ease of preparation and testing are advantages unique to the chevron-notch specimen used for the determination of the plane strain fracture toughness of extremely brittle materials. During testing, a crack develops at the notch tip and extends stably as the load is increased. For a given specimen and notch configuration, maximum load always occurs at the same relative crack length independent of the material. Fracture toughness is determined from the maximum load with no need for crack length measurement. Chevron notch acuity is relatively unimportant since a crack is produced during specimen loading. In this paper, the authors use their previously determined stress intensity factor relationship for the chevron-notch short bar specimen to examine the performance of that specimen in determining the plane strain fracture toughness of silicon nitride and aluminum oxide.
Stress Relaxation in Bending of Copper Beryllium Alloy Strip
Authors: Fox A 
Published: February 2009

AbstractThe stress-relaxation behavior of two copper beryllium alloys in strip form, Copper Alloy UNS No. C17000 and C17200, was studied in the temperature range 23 to 232°C (73 to 450°F). The behavior of mill-hardened material is compared to that of material having been fully precipitation heat-treated. Analysis of the data indicates that stress relaxation is a function of test temperature, prior cold work, and the subsequent aging treatment. At temperatures of 177°C (350°F) and above, the stress relaxation of the mill-hardened alloys appears to be affected by simultaneous aging at the test temperature. In addition to stress-relaxation data the alloys studied are characterized by their tensile and bending properties as well as electrical conductivity.
Erosion and Cavity Characteristics in Rotating Components
Authors: Veerabhadra Rao P , Syamala Rao BC , Lakshmana Rao NS 
Published: February 2009

Abstract
An investigation of the initiation and growth of erosion and of the effect of velocity and pressure on erosion in a rotating disk is presented. Also, the role of an intervening noncavitating period on erosion is studied. The results indicate that at high intensities the peak rate of erosion decreases with increases in pressure. The erosion rate/time curves obtained for metallic materials are explained by the eroded particle distribution and the cavity size. The average size of the eroded particles decreased when pressure and tensile strength of the material were increased. The erosion rate peaked after an intervening noncavitating period. The use of the rate of erosion, defined as an average over the entire test duration, in the equation governing the theory of erosion resulted in reasonably good correlations. The correlations reveal that it is possible to predict the length, width, and area of a cavity when the cavitation parameter σ is known. The normalized width of a cavity may be estimated if its normalized length is known.
Results of an ASTM Cooperative Test Program on theJIc Determination of HY130 Steel
Authors: Clarke GA , Landes JD , Begley JA 
Published: February 2009

AbstractA cooperative test program to evaluate testing procedures for the determination of JIc was organized under the auspices of ASTM. The material tested in this program was HY130 steel. A total of 21 laboratories in five different countries participated in this testing program. Although considerable scatter was found in the JIc results from various laboratories much of the scatter was attributed to material properties variations.From the results of this program a recommended testing procedure was developed by a working group formed by the ASTM Task Group on Elastic-Plastic Fracture, E24.01.09. The data from the cooperative test program is presented along with the reasoning for developing the recommended JIc test procedure.
MeasuringJIc, and the Resistance to Crack Growth After Initiation
Authors: Early PW , Burns SJ 
Published: February 2009

AbstractA ductile fracture toughness (JIc) test that uses fracture specimens with finite differences in crack area is reviewed. Experimental results are given for Ti-6Al-4V, A471 Ni-Cr-Mo-V rotor steel, and 4140 high strength steel. Resistance to further crack propagation after initiation is discussed in terms of the tearing modulus, which is equal to dJ/dA, A being the crack area. A useful expression for the tearing modulus is given.
A Hot Compression Testing Apparatus for the Study of Isothermal Forging
Authors: Immarigeon J-PA , Kandeil AY , Wallace W , de Malherbe MC 
Published: February 2009

Abstract
An apparatus for uniaxial compression testing has been developed to simulate isothermal forging conditions. The system is capable of applying 100-kN loads at temperatures up to 1200 ± 3°C in a controlled environment and at constant true strain rates between 10−5/s and 1/s. The apparatus is described and its performance discussed. To illustrate its use, results on the flow behavior of nickelbase superalloy compacts and composites are presented that demonstrate the importance of proper control of the testing parameters. The difference in flow strength of the two materials under identical testing conditions is discussed.
Development of a Chronic Toxicity Test Using Chironomus riparius and the Sublethal Effects of Trisodium Carboxymethyloxysuccinate
Authors: Lee CM , Fullard JF , Huntington E 
Published: February 2009

Abstract
The preliminary development of a 24- to 34-day life-cycle test using the freshwater midge Chironomus riparius is described. The method allows the determination of the sublethal effects of a toxicant on the survival of each life stage, overall growth of the larval stages, egg production, and hatchability of the F1 generation eggs. Trisodium carboxymethyloxysuccinate (Na3CMOS), a potential partial replacement for phosphates in fabric washing powders, is used to demonstrate the method.
There was no effect on survival from stage to stage or overall survival from the egg to the fourth larval instar at up to 92 mg/L Na3CMOS. There were no effects on growth or egg production at ≤92 mg/L Na3CMOS or on hatchability of the F1 eggs at ≤42 mg/L Na3CMOS. None of the F1 generation eggs hatched in 92 mg/L Na3CMOS. The number of adults produced clearly decreased with increasing concentration &gt;12 mg/L Na3CMOS but, in this preliminary work the data did not permit statistical verification of the threshold of effect.
This method has been shown to be sensitive enough to identify sublethal effects of toxicants and shows considerable promise as a method for hazard evaluation. Limited evidence suggests that the test species C. riparius has a sensitivity to toxicants of a similar order to other commonly used test organisms.
Room Temperature Capacitance and Dissipation Factor Measurement of Chip Capacitors—An Interlaboratory Evaluation
Authors: Lo WC 
Published: February 2009

Abstract
An interlaboratory test on room temperature measurement of unencapsulated multilayer ceramic capacitors (commonly known as chip capacitors) was conducted under the sponsorship of ASTM Committee F01 on Electronics. Results show that a well-defined method of test is needed to get agreement among mesurements of capacitance and dissipation factors for this type of capacitor.
Fatigue Life Prediction of Welded Components Based on Fracture Mechanics
Authors: El Haddad MH , Topper TH , Smith IFC 
Published: February 2009

Abstract
An elastic-plastic fracture mechanics solution for fatigue cracks initiating from weld toes is introduced that admits plasticity by replacing the conventional stress term with a strain term. It accounts for the propagation of very short cracks by the introduction of an effective crack length equal to the actual length increased by an amount l0, where l0 is a constant characteristic of the material and material condition. Consideration is also given to the effect of mean stress and crack front shape on an intensity factor derived from this solution. Crack growth results for cracks in both elastic and plastic strain fields of welded specimens, when interpreted in terms of the intensity factor, show excellent agreement with elastic long crack data. This intensity factor, when combined with a propagation model that includes all stages of crack growth, also successfully predicts the entire life of butt- and fillet-welded specimens for two steels. The threshold stress corresponding to the failure of butt-welded specimens is equal to the smooth specimen fatigue limit stress divided by the elastic stress concentration factor. However, for fillet welds, the stress level corresponding to failure is higher than the fatigue limit stress divided by the elastic stress concentration factor. At stresses between these two stress levels, cracks start at fillet-weld toes but do not propagate to failure.
A Proposed Standard Round Compact Specimen for Plane Strain Fracture Toughness Testing
Authors: Underwood JH , Newman JC , Seeley RR 
Published: February 2009

Abstract
A round, disk-shaped specimen is proposed as a standard test specimen for addition to ASTM Test for Plane-Strain Fracture Toughness of Metallic Materials (E 399-78a). The specimen is diametrically cracked, and it is loaded in the same general way as the existing standard compact specimen. Tests and analyses were performed to verify that the proposed round compact specimen and associated stress intensity factor K solution are appropriate for a standard plane strain fracture toughness test. The use of the round compact specimen for other fracture tests is described.
A Wide Range Stress Intensity Factor Expression for the C-Shaped Specimen
Authors: Kapp JA , Newman JC , Underwood JH 
Published: February 2009

Abstract
A new expression has been developed to calculate the stress intensity factor K for the C-shaped specimen over a wider range of specimen parameters, namely, crack depth to width ratio a/W, load eccentricity X/W, and radii ratio r1/r2, than had previously been available. The rationale for the expression was to use known K solutions for short and deep cracks to develop a nondimensional form of K. This nondimensional form of K approaches the correct limiting values as a/W goes to both zero and one. Numerical K results from previous work were then nondimensionalized to this form and the dependence of K on a/W was determined by multivariable linear regression. The final expression agrees with the numerical K solutions within ±1.0% for 0.45 ≤ a/W ≤ 0.55 for all r1/r2 and X/W of either 0 or 0.5; within ±1.5% for 0.2 ≤ a/W ≤ 1 for all r1/r2 and X/W equal to 0 or 0.5; and within ±3% for 0.2 ≤ a/W ≤ 1 for all r1/r2 and 0 ≤ X/W ≤ 1. The accuracy of this expression will allow expanded use of the C-shaped specimen for crack growth resistance curve determination and fatigue crack growth rate testing.
Vibrations in Compact Specimens During Crack Arrest Testing
Authors: Rahka K 
Published: February 2009

AbstractMeasurements of loading arm behavior on compact tension type, transversely wedge-loaded crack arrest specimens have been made. A crack-opening measurement point close to the crack initiation site was selected in addition to face or load-line position. Conclusions concerning acceleration, vibration, and damping behavior of the specimen arms were reached and differences in the behavior of two alternative specimen types are indicated. The influence of fracture morphology on specimen behavior is reported in detail. Suggestions for further work to clarify crack run-arrest behavior of tentative test specimens are presented.
Vibratory Horn Cavitation Erosion Comparisons
Authors: Hammitt FG , Okada T 
Published: February 2009

Abstract
Results of tests of vibratory horn cavitation erosion conducted at Fukui University, Fukui, Japan, and the University of Michigan, Ann Arbor, are compared. The tests were primarily for mild carbon steels (equivalent to Type 1018). The results from Fukui University for various other materials are also included. The maximum mean depth of penetration rate (MDPRmax) varies approximately as horn amplitude to the 1.5 power, and there are strong increases in MDPRmax for increased specimen diameter. There are also strong effects of horn frequency.
Effect of Specimen Shape and Cyclic Loading on Tension Tests of Two Epoxy Resins
Authors: Findley WN , Reed RM 
Published: February 2009

Abstract
Cyclic load experiments are reported for two epoxies, one containing rubber particles. With and without interruptions during unloading, the experiments were performed on an Instron machine at a constant rate of head motion using an averaging extensometer capable of strain to fracture and having no dead zone. Results of interrupted unloading tests show the effect of elasticity of the portion of the specimen outside the gage length on the observed stress-strain curves.
A Procedure for Strain-Controlled High-Cycle Fatigue Testing at Elevated Temperatures
Authors: Majumdar S , Raske DT , Burke WF 
Published: February 2009

Abstract
A procedure for conducting high-cycle fatigue tests under indirect axial strain control is presented. Stroke control is maintained throughout the tests. However, the frequency of cycling is periodically reduced so that the axial strain can be measured directly, and the stroke signal is adjusted to correct any drift in the axial strain signal. Tests have been conducted to demonstrate the viability of such a procedure.
Effect of Understressing and Coaxing on the Fatigue Limit of a Transverse Butt-Welded Joint
Authors: Lawnicki JJ , Cutler VC 
Published: February 2009

Abstract
A test program was developed to compare both the effects of thermal stress relief and “understressing” and “coaxing” techniques on the predetermined fatigue limits of selected weldments. Approximately 100 specimens were cut from 1025 welded plate and reduced to a finished size of 6.35 mm (0.25 in.) thick by 31.75 mm (1.25 in.) wide by 279.4 mm (11 in.) long. A 6.35-mm (0.25-in.) diameter hole was drilled in the weld to control the failure location. The specimens were subjected to fully reversed bending at selected stress increments until failure occurred. The results indicated that understressing and coaxing produced a marked increase in the effective fatigue limit for all specimens with the most significant increase observed in the specimens that had no thermal stress relief of the weldments. One of the practical applications might be in a case in which a controlled break-in period for welded components is feasible and thermal stress relieving is not.
Chevron V-Notched Bend Specimen for KIc Measurement of Brittle Materials
Authors: Shih TT 
Published: February 2009

Abstract
A chevron V-notched bend specimen is proposed for plane-strain fracture toughness KIc testing of brittle materials. This specimen has the following distinctive advantages over more conventional toughness specimens: (1) the simple geometry can easily be machined, (2) no fatigue precracking is required, (3) no crack length measurements are required (KIc can be calculated from knowledge of the peak load alone), and (4) the test can easily be conducted at elevated temperatures. The proposed specimen was calibrated with a 7079-T6 aluminum alloy of known fracture toughness. Subsequently, the fracture toughness of the ceramic material Pyroceram® 9606 was determined with the same specimen design. The reproducibility of KIc values was found to be excellent: 2.64 MPa·m1/2 ± 3% (2.39 ksi·in.1/2 ± 3%). The proposed specimen design is also recommended as an inexpensive toughness screening test for other structural materials. The chevron V-notch crack starter used in the bend bar specimen is also recommended for use in other specimen designs to improve the capability for both fatigue and stress corrosion threshold testing. In view of the tremendous cost- and time-saving potential associated with the chevron V-notch design, it is recommended that a detailed finite element analysis be performed on this configuration to further substantiate the applied stress and stress intensity conditions.