bluuebunny/crossref_metadata_2025 huggingface dataset:
Strength, Volume Changes, and Sulfate Resistance of Mortars Containing Portland-Pozzolan Cements
Authors: Davis RE , Hanna WC , Brown EH
Published: September 2009

This paper may be considered as a supplement to an earlier paper dealing with the properties of mortars and concretes containing portland-pozzolan cements and other blends. Herein, for mortars there are given the strengths and volume changes up to the age of 10 yr. and the resistance to the action of sodium-sulfate solutions up to the age of one year.

Mortar specimens containing portland cements within the ordinary range of composition, under laboratory conditions of continuous wet storage, exhibited retrogression in both tensile and compressive strengths. Corresponding specimens containing cement replacements of finely divided pozzolanic materials in general showed no such retrogression. Those containing the less active volcanic glasses, such as pumicite, continued to increase in tensile strength up to the age of 10 yr.; those containing the more active opaline shales generally acquired their maximum strength at an earlier age, but some continued to increase in compressive strength up to the age of 10 yr.

Under continuous drying conditions, after a preliminary period of moist curing, mortars containing portland cements within the ordinary range of composition continued to increase in strength up to the age of 10 yr. This was also true for blended cements where the replacement was 30 per cent or less, including not only such pozzolanic materials as volcanic glasses, opaline shales, and calcined clays, but also including limestone dust.

In general, the long-time drying shrinkage of mortars containing blended cements was greater than that of mortar containing the corresponding straight portland cement; blended cements containing limestone replacements were exceptions. The long-time drying shrinkage of mortars containing cements high in tricalcium silicate was less than that for corresponding mortars containing cements low in tricalcium silicate. The long-time expansion of mortars under continuously wet conditions was somewhat greater for portland-pozzolan cements than for the corresponding straight portland cement.

The use of such pozzolans as Monterey shale and pumicite in blended cements materially improved resistance to sulfate action. In general, blends containing calcined or uncalcined clays, and crystalline silicas such as quartz and granite were little, if any, more resistant to sulfate action than the corresponding straight portland cement. The use of limestone dust led to some improvement in sulfate resistance.
The Application of Vacuum Fusion to Gas-Metal Studies
Authors: Beach A. L. , Guldner W. G.
Published: September 2009

In the past decade, we have all witnessed the development of metals with respect to high purity or controlled impurity. Such work has progressed as the result of the cooperative efforts of the metallurgist, engineer, physicist and chemist. At the Bell Telephone Laboratories, there are innumerable research and development problems involving a wide range of materials for which the chemist must provide adequate means of testing. Vacuum fusion analysis is one such method which must progress in technique and development to meet the demand. Because of the common knowledgeof this technique which has been widely published, only the apparatus and the highlights of the procedure are outlined here. This presentation covers some aspects in the study of nickel used in the electronic field. Then, with some of these projected thoughts in mind, some current problems that have developed in extending the vacuum fusion method to a study of other metals, namely, germanium, silicon, tantalum and molybdenum are reviewed. No doubt, many laboratories have carried out extensive studies of one or more of these metals and have encountered some of the difficulties presented here.
Emission Spectrometric Determination of Oxygen in Metals
Authors: Fassel Velmer A. , Gordon William A. , Tabeling Ray W.
Published: September 2009

The problems encountered in extending emission spectrometric methods to the determination of the oxygen content of metals are surveyed and several techniques for surmounting some of these problems are discussed. Methods for the determination of oxygen in steel, titanium, the rare earths, and other metals are presented in detail. These procedures are based on the liberation of the oxygen content of the metal into an argon atmosphere by the high temperatures attained in direct-current arc discharges. The intensity ratio of the line pair 07771Å/A7891Å is related to the oxygen content of the metal sample. The procedures described determine oxygen with a precision comparable to vacuum fusion or bromination — carbon reduction techniques and have the advantage of greatly reduced time requirements.
The Role of Smokeless Powder in the Season Cracking of Small Arms Ammunition
Authors: Mitchell J. W.
Published: September 2009

Season cracking of 70-30 cartridge brass cases of small arms and artillery ammunition has been under investigation at the Frankford Arsenal for many years. The nature of this stress-corrosion failure has been found to be intergranular. Much of this work, however, has been directed toward improvements in method of manufacturing the cases so as to reduce the tendency to season crack and little progress had been made toward finding the source of the chemical agent producing the intergranular corrosion.
Season Cracking of Brass
Authors: Edmunds Gerald
Published: September 2009

Although the phenomenon of season cracking is still imperfectly understood, there seems to be ample evidence that season cracks are propagated by the combined action of corrosion and a stress of either internal (residual) origin or external origin. The factors that influence season cracking may therefore be grouped according to corrosive media, nature of stress, and character of the material.
The Mechanism of the Season Cracking of Brass
Authors: Read T. A. , Reed J. B. , Rosenthal H.
Published: September 2009

Although the season cracking of brass has been a subject of experimental investigation for more than thirty years, the mechanism that is responsible for this phenomenon is still obscure. While attempts to elucidate the stress-corrosion cracking of some alloys have been relatively successful, the principal accomplishments made in the studies of the season cracking of brass have consisted of improved techniques for the fabrication of articles of alpha brass, which reduce the danger of season-cracking failure in service.
Residual Stress in Caliber 0.30 Cartridge Cases
Authors: Rosenthal H. , Mazia J.
Published: September 2009

An investigation has been made of residual stress in the head and body of caliber 0.30 cartridge cases. The head was divided into four ring-like sections which were cut off by a jeweler's saw. Spring-out was measured after a radial cut had relieved the circumferential bending moment. The residual stress corresponding to the observed spring-out was calculated by formulas in which the computed stress was a function of wall thickness. All rings sprang open, indicating compressive stress on the inner wall and tensile stress on the outer wall. The production stress-relief anneal of 475 F. for 45 min. reduced the stress to almost half. The priming and crimping operation, however, again raised the stress, especially in the flange section. The effect of stress-relief heat treatments on residual stresses in the body of caliber 0.30 cartridge cases was investigated by the split-ring method. Although this method did not reveal any large stresses in the body, the neck before mouth anneal was found to contain a computed stress of 30,000 psi. at the surface. This value was reduced to 15,000 psi. in 120, 30, and 15 min. at 400, 475, and 500 F., respectively.
A Damping Test for Season Cracks in Cartridge Brass
Authors: Read T. A. , Kitchen S. W. , Fusfeld H. I.
Published: September 2009

At the present time most artillery cartridge cases are used only a single time. Since the process of reshaping a fired cartridge case so that it may be used again is much simpler and cheaper than the original manufacture of the case, it is clear that important savings could be effected if such reformed cases were used in place of new cases. Extensive use of reconditioned cases has been hindered in the past, however, by the deterioration of the brass which may occur in the period of time between the first firing and the reconditioning of the cartridge cases. This deterioration sometimes results in a dangerously high incidence of firing splits in groups of reconditioned cartridge cases. It appears that the mechanism of the deterioration is the season cracking of the brass, for season cracks, of varying degrees of severity, may frequently be found in the cartridge cases after their return from the field. There are, of course, severe practical limitations to the extent to which fired cartridge cases can be protected from corrosion under battle conditions, particularly since the powder residue in the case is itself corrosive.
Protective Resin Films on Cartridge Brass
Authors: Gisser H.
Published: September 2009

Recent experimental work has demonstrated(I) that ammonia and oxides of nitrogen are formed during the aging of smokeless powder. This is significant in connection with the problem of “season cracking,” or stress corrosion of brass cartridge cases in view of other work(I) indicating that stressed and “stress-relieved ” cases stored with small quantities of added ammonium nitrate crack on firing. The deterioration of stressed brass by ammonia has been known for some time(2) and it appears therefore that stress-corrosion cracking of brass cartridge cases is intimately associated with the so-called “powder volatiles,” ammonia and oxides of nitrogen, both of which are decomposition products of smokeless powder. Working on the hypothesis that any barrier which prevents the powder volatiles from reaching the brass surface will reduce the incidence of stress-corrosion cracking, it was considered desirable to investigate the use of organic resin films to accomplish this purpose.
Factors Influencing the Stress Cracking of Brass Cartridge Cases
Authors: Sachs George , Espey George , Clark S. M.
Published: September 2009

Part I: The tendency of a commercially drawn cartridge case to crack in the mercury test and the relation of cracking tendency to residual stress retained after drawing were studied. The fourth drawpiece (next to the final) of caliber 0.30 cartridge cases produced by Frankford Arsenal were selected as test pieces. These exhibited an exceptionally high cracking tendency, making a detailed study possible.

To obtain fast cracking in the mercury test, about 0.0015 to 0.003 in. must be removed from the wall thickness of the drawpiece by pickling, and it must be subjected to the mercury test immediately after washing. Removal of the adhering mercury by annealing and subsequent squeezing of the case in a vise was used to reveal definitely the presence or absence of cracks.

Various lots of apparently identically fabricated cases were shown to possess a different cracking tendency.

Machining off or boring a hole in the base gradually reduced and eventually eliminated the cracking tendency. On the contrary, shortening of the wall (body) reduced the cracking tendency only if the wall became so short that the cracking zone was directly affected.

By boring out the base and pickling from the outside and then splitting the resulting rings, it was possible to determine the approximate stress distribution in the base and in the adjacent part of the wall. Small compression stresses were present in the core and the major part of the base, while the surface of the base and the adjacent wall contained high circumferential tensile stresses. On the contrary, the wall when parted from the base contained only insignificant residual stress.

The conception is advanced, that the stress distribution in a drawn cartridge case corresponds fundamentally to that of a tube (wall) shrunk on a disk (base). Such a stress distribution results from the tendency of the base to recover elastically by an increase in diameter from the biaxial compression during drawing while the wall exhibits little tendency to change its diameter after progressing through the die. This is confirmed by measurements which show the base diameter to be slightly larger than the wall diameter.

Part II: The effect of a number of processing (drawing) variables on the cracking tendency was also investigated.

The principal result was that the use of dies with small angles combined with a small reduction in diameter resulted in drawpieces with no tendency to crack. This also applied to large die angles used in combination with large diameter reductions, with a die angle of approximately 10 deg. giving the highest cracking tendency.

It was also found that the larger the grain size, the greater the tendency to crack. Other variables showed no definite effect upon the cracking tendency.
Test Methods and Progress in the Stress-Corrosion Investigation at Wright Field
Authors: Madden Baxter C.
Published: September 2009

Stress corrosion is defined and certain examples are illustrated. A number of test methods, to determine the resistance of materials to stress corrosion, are being developed at Wright Field. The criterion as to the validity of a method is stated. Three types of specimens and the method of stressing each type are described. Five different corrosive conditions are set forth. The results of tests to date, although too few for any general conclusions to be arrived at, are presented. The program for the continuation of the investigation is indicated. A bibliography is included. The development of the method of loading a cantilever-type specimen, so that a nearly constant stress at a large deflection may be realized, is presented as Appendix I.
Stress Corrosion in Relation to Aircraft Components
Authors: George C. W. , Chalmers Bruce
Published: September 2009

The authors enumerate the factors which appear, from their observations and practical experience of failure of aircraft components in Great Britain, to be responsible for causing a metal or alloy to fail by stress corrosion.

The essential conditions for promoting failure by stress corrosion are: (1) tensile stress at the surface of the component, (either residual or applied), and (2) an attacking medium that may be a solution or a liquid metal. Particular attacking agents are effective only on certain metals. In all instances of stress-corrosion failure experienced, cracking of an intercrystalline form has occurred and examples of such failure in aluminum alloy, steel and copper alloys are described and illustrated. The relation between microstructure and stress corrosion is mentioned and methods of investigating the susceptibility to stress-corrosion failure of metallic materials are described. The precautions to be taken in selecting materials for particular aircraft components and the importance of adequate protection against chemical attack are considered. The authors have given a factual survey of stress corrosion and have made no attempt to advance any scientific explanation of the phenomenon.
The Assessment of the Susceptibility of Aluminum Alloys to Stress Corrosion
Authors: Champion F. A.
Published: September 2009

The work described in this paper was carried out in the Research Laboratories of the British Aluminium Company Ltd., under the general direction of A. G. C. Gwyer, Scientific Manager of the Company.
Elevated Temperature Tension Tests on Galvanized Steels
Authors: Craig J. H.
Published: September 2009

As a result of information that the Navy Department was questioning the advisability of raising the maximum allowable exposure temperature for zinc-coated steel parts from 500 to 750 F., it was decided to make a series of high temperature tension tests on several types of uncoated and zinc-coated steels. The objective was to determine at what temperature intergranular penetration of galvanized steel by zinc might take place under conditions of rapidly applied stress and temperature.

Tests were conducted in the range from room temperature to 1400 F. In this range, low-carbon and high-carbon steels did not suffer any adverse effects due to zinc coatings. In fact, at 1400 F. the zinc coatings appeared to have a beneficial effect. In stainless steel, the coating had no effect up to 1000 F. Above this temperature, the zinc coating appeared to cause a marked loss in ductility and a less pronounced loss in strength. There was no visible evidence of zinc penetration of the stainless steel structure, but it was assumed that this was the cause of the adverse effect.
The Susceptibility of Austenitic Stainless Steels to Stress-Corrosion Cracking
Authors: Franks Russell , Binder W. O. , Brown Charles M.
Published: September 2009

Occasionally in the application of the austenitic chromium-nickel steels to corrosive conditions, failures have occurred by cracking without serious general over-all attack of the metal. As pointed out by Hoyt and Scheil(1), and by Scheil, et al.(2) as well as by Hodge and Miller(3), the stress-corrosion failures that have occurred have been limited in number, and have taken place only when the steels were exposed to certain corrodents. These investigators have stated that while stress-corrosion cracking can be intergranular in nature and originate at the grain boundaries of the austenitic chromium-nickel steels, it can also take place in transgranular fashion. They have shown that the cracking may be either initiated at the grain boundaries and may propagate along grain boundaries for some distance and then suddenly extend across grains, or it may begin in a transgranular fashion and suddenly proceed along grain boundaries until the cracking stops. Their data further show that when austenitic stainless steel is subject to intergranular attack, stress will concentrate and cause cracking in service.
Some Examples of Stress Corrosion Cracking of Austenitic Stainless Steel
Authors: Ellis O. B.
Published: September 2009

Although thousands of tons of stainless steel have been used successfully for many types of equipment, there have been few cases of failures due to the phenomenon described as stress corrosion cracking.
Stress-Corrosion Tests of Bridge-Cable Wire
Authors: Pollard R. E.
Published: September 2009

The National Bureau of Standards received, in August 1940, a number ofsamples of bridge wire taken from thecables of the General U. S. Grant suspensionbridge over the Ohio River at Portsmouth,Ohio. These cables were 71/8 in. indiameter under the wrapping and each wasmade up of 1458 ungalvanized wires ofNo. 8 gage in 3 parallel-wire strands. Thechoice of ungalvanized wire was basedon the previous satisfactory performanceof similar wires in other bridges overperiods of 20 to 50 yr. of service(i).
The Effect of a Coating of Polybutene on the Fatigue Properties of Lead Alloys
Authors: Ferguson Lawrence , Bouton George M.
Published: September 2009

The experiments described in this publicationwere inspired by the Bell System'slarge interest in lead-alloy sheathed cablesand by the wide range of fatigue andcorroding conditions to which they aresometimes subjected in service. The firstexperiments consisted of operating specimensof lead + 1 per cent antimony telephonecable sheath alloy in a fatigue testwhile they were immersed in water takenfrom a manhole. Because of many publishedreports concerning corrosion-fatiguephenomena of various metals and alloys,a reduction in fatigue life was expected(1).the form of a coating, was found to adhereto the specimens better than most othersand to have a large effect on fatigue properties.For this reason, the effect of thismaterial was studied more completely andthe results form the chief subject matterof this paper.
Fundamental Viscosity and How It is Measured
Authors: Levy D F
Published: September 2009

This paper covers definitions of fundamental viscosity, absolute viscosity, and kinematic viscosity. The various units and terminology used to measure viscosity are defined. Other factors contributing to a better understanding of the nature of viscosity are discussed, such as types of fluid flow, Reynolds number, and initial and apparent viscosity. Several viscometers currently in use in industry and research are covered briefly. The general range of application, operation, and the normally expected precision of each type of viscometer are discussed.
Relation of Empirical Tests to Fundamental Viscosity of Asphalt Cement
Authors: Griffith J M , Puzinauskas V P
Published: September 2009

During the past two years, a cooperative viscosity testing program under the sponsorship of The Asphalt Institute, has been conducted on a range of commercially available asphalt cements. The program was designed (1) to develop an accurate method for viscosity measurement of asphalt cements at 140 F and (2) to compare the consistency characteristics of asphalt cements as measured by a fundamental viscosity test. The results of this program to date are discussed.
The Relation of Absolute Viscosity of Asphalt Binder to Stability of Asphalt Mixtures
Authors: Welborn J Y , Halstead W J , Olsen R E
Published: September 2009

Several investigations have correlated various consistency measurements with stabilities of asphalt paving mixes. However, because of the experimental variations encountered and the time-consuming tests required to secure complete information, the quantitative relationship of viscosity to compressive strength for mixtures of various types has not been specifically established. In addition to generally reviewing the literature, this paper reports the results of a study of the relationship of absolute viscosity to compressive strength tests for several asphalts from different sources and at different temperatures. Most comparisons have been made on the basis of the viscosity of the asphalt recovered from the strength-test specimen.
Application of Asphalt Viscosity to Paving Problems
Authors: Griffin R L , Izatt J O , Lettier J A
Published: September 2009

Information on (1) the viscosity levels that permit the most efficient pavement construction operations and (2) the viscosity factors most desirable for pavement performance is meager and clouded by the influences of asphalt mix compositions. The temperature viscosity and viscosity rate of shear characteristics of the asphalts can be measured on the original material and on material separated from the mixes and from the pavement. These viscosity factors can be used in the design and construction of the asphalt pavement and for comparing the performances of the asphalts.
Viscoelastic Properties of Paving Asphalts
Authors: Gzemski F C
Published: September 2009

This paper reviews the basic flow properties of asphalts and presents experimental data on the effect of shear rate on viscosity of paving asphalts at various temperatures. The oversimplified flow or rheological patterns of asphalts presented here are intended primarily to create an awareness of the basic parameters and engineering yardsticks which, when applied, will lead to a better understanding of asphalt pavement behaviors and eventually lead to their implementation in the engineering design of pavements.

A basic understanding of the language of rheology, a knowledge of the basic theory of the rheology of asphalt, and a familiarity with the necessary instrumentation are required before these concepts can be effectively implemented as performance standards.
Use of Load Tests in the Design of Flexible Pavements
Authors: Campen W. H. , Smith J. R.
Published: September 2009

This paper describes a method for utilizing load tests for the design of flexible pavements. Rigid circular plates are used to represent tires of equivalent contact areas, and load bearing values are determined at ¼-in. total deformation.

The procedure involves four steps as follows:

1. Load-deformation data are obtained, on top of the subgrade and superimposed sub-base and base layers, with plates of 216, 432, and 800-sq. in. areas.

2. Using the data thus obtained, load-deformation curves are constructed from which load-bearing values at ¼-in. deformation are selected.

3. Using the load-bearing values at ¼-in. deformation and the perimeter-area ratios of the plates, straight-line relations are established, between load-bearing value and size of testing plate, for each stage of the layered system. This arrangement of the data constitutes a strength-thickness relation for the three plates used as well as for all intermediate sizes.

4. This graph is used to determine sub-base and base thicknesses required to handle desired loads on desired plates.

Two graphs, constructed from field data, are included in the paper and are used to illustrate the application of the design method.

The paper also discusses, and includes data on, the following phases of the design problem:

(a) Resistance of densified soils to the destructive forces of nature,

(b) Elastic deformation as a basis of design,

(c) Repetitive loading as a basis of design,

(d) Variation of bearing capacity (strength) with size of testing plate,

(e) Subgrade bearing capacity (strength) and (strength imparting) increased supporting power of superimposed layers, and

(f) Effect of loaded plates on surfaces adjacent to the plates.
Field Bearing Tests Applied To Pavement Design
Authors: Philippe Robert R.
Published: September 2009

In earlier studies by the Rigid Pavement Laboratory, of field bearing tests applied to pavement design, only slight consideration was given to the effects of repetitions of low pressure loads. Bearing values based upon deformations under increments of a single loading cycle were considered adequate. However, later investigations have indicated that soil behavior under subsidence caused by numerous repetitions of low-pressure loads will require a revision of the bearing-test procedure to evaluate correctly values on the basis of progressive soil deformation.

This paper discusses a revision of the field bearing-test procedure and shows how its application may permit refinements in airfield-pavement design to the extent of considering the effects of repetitive loads which occur on taxiways, longtime static loads such as occur on hardstanding areas, and quick loads of very short duration which occur on runway pavements as aircraft either land or take off.
A Cyclic Load-Test Procedure
Authors: Hittle Jean E. , Goetz W. H.
Published: September 2009

In recent years there has been a concerted effort by highway and airport engineers to develop methods of evaluating the supporting power of subgrades, base courses, and finished pavement designs by means of loading or bearing tests. From the investigations and testing programs of the various engineering organizations in charge of pavement design and construction, much has been learned about the technique of conducting loading tests and the interpretation of test results. In addition to the influence on load-test results of the strength characteristics of the subgrade soil, base materials, and paving materials, it is generally recognized that: (1) the size of bearing plate, (2) the magnitude of the load increments, (3) the terminal rate of plate movement for a given load increment, and (4) the sequence and arrangement of the load-test procedure itself have influence on the test results.
A Canadian Investigation of Load Testing Applied to Pavement Design
Authors: McLeod Norman W.
Published: September 2009

Repetitive plate bearing tests have been made on the subgrades, base courses, and flexible surfaces of the runways at ten Canadian airports.

Useful correlations are given, by means of which limited load test data may be extrapolated to other bearing plate sizes between 12 and 42 in. in diameter and probably beyond, and to any deflection over the range of at least 0.0 to 0.7 in.

Subgrade load test data have been correlated with cone bearing, Housel penetrometer, field California Bearing Ratio, and triaxial compression tests.

The probable influence of repetitive loading and bearing plate size on the value of the subgrade modulus k for rigid pavement design is indicated.

A method of design for the thickness of flexible pavements is developed, which has been correlated with runway service performance under airplane traffic in Canada.

Charts of design curves for required thickness of flexible pavements have been prepared for a wide range of airplane wheel loadings for runways and for taxiways, and for the normal range of highway wheel loadings.
Metallographic Specimen Preparation by Vibratory Polishing
Authors: Rothstein P , Turner F R
Published: September 2009

In a modern laboratory where the metallographer is expected to utilize his time most efficiently, the time-consuming hand-polishing procedures are good candidates for automation. One of the first and most promising efforts in this direction was the development of vibratory polishing by Long and Gray (1,2) and Krill (3).
Low-Cycle Axial Fatigue Behavior of Mild Steel
Authors: Yao J. T.P. , Munse W. H.
Published: September 2009

A general hypothesis that describes the cumulative effect of plastic deformations on the low-cycle fatigue behavior of metals is presented and verified with results of a variety of tests on steel specimens. Limited correlations with existing test data from other low-cycle fatigue tests on aluminum-alloy specimens indicate that it may be possible also to extend this hypothesis to metals other than steel.
Low-Cycle Fatigue Properties of Complex Welded Joints of High-Strength 301, 304L, 310, and AM-355 Stainless Steel Sheet Materials at Cryogenic Temperatures
Authors: Christian J. L. , Hurlich A. , Watson J. F.
Published: September 2009

The high-stress, low-cycle fatigue properties of several complex welded joints were determined on types 301, 304L, 310, and AM-355 stainless steels at 78, −320, and −423 F. The welded joints were designed to give nearly 100 per cent static tension joint efficiency and are typical of joint designs of high-strength, thin sheet materials used in missile and space craft fabrication. The number of cycles to failure were obtained at 75, 85, and 95 per cent of the typical yield strength of the parent metal at each corresponding temperature or at 75, 85 and 95 per cent of the static tensile strength of the complex welded joint in the event that failure occurred below the yield strength of the parent metal. Five replicate fatigue specimens (test section of 4 by 16 in.) were tested in each test condition of temperature and stress level. The average number of cycles to failure varied from 5 to 1750 depending upon the material and test conditions.

The data indicate that 60 per cent cold-rolled type 301 stainless steel possesses the most desirable joint fatigue properties at 78 F; at −320 F, types 301, 304L, and 310 stainless steel have nearly identical joint fatigue properties. At −423 F, 75 per cent cold-rolled 310 and 50 per cent cold-rolled 304L stainless steels have the most desirable joint fatigue properties.

The tensile properties of the parent materials and of simple fusion welds and resistance spot welds were determined at 78, −100, −320, and −423 F. Also, notched tensile strengths were determined with specimens having stress concentration, Kt, values from 3.2 to 19.0 at the same temperatures. Correlation of the tensile and notched tensile data with the fatigue results are given.
Effect of Stress State on High-Temperature Low-Cycle Fatigue
Authors: Kennedy C. R.
Published: September 2009

A study of the behavior of Inconel at 1500 F under realistic dynamic stress states has been made to evaluate critically the present criteria used to solve low-cycle fatigue problems and to demonstrate their applicability for the more complex situations. The relative agreement between the static complex stress-creep-rupture results and the low-cycle fatigue data is demonstrated. From the relationships developed for static complex stress-creep-rupture data, it is shown that the magnitudes of the effects of stress state and frequency on low-cycle fatigue can be determined.
Empirical Analysis of Fatigue Strength of Pin-Loaded Lug Joints
Authors: Mittenbergs A. A.
Published: September 2009

Fatigue data obtained in an experimental research program on SAE 4340 steel and 2024-T4 aluminum alloy pin-loaded lug joints are analyzed with respect to stresses at the location of failure. These lug joints were subjected to a combined load consisting of a steady-tension component and an alternating, reversed cantilever-type bending moment. The paper reviews briefly the experimental data and presents an approach and an empirical method for failure prediction in pin-loaded lug joints under the above fatigue loading. The nominal stresses at failure are expressed as functions of the material properties, geometric parameters of the joints, and other pertinent factors. The method developed permits correlation of nearly all observed fatigue-test results and appears potentially useful for analyses of other experimental results on pin-loaded lug joints.
Aircraft Structural Fatigue Research in the Navy
Authors: Rosenfeld M. S.
Published: September 2009

Twenty-six unused fighter aircraft were made available for use in an investigation to determine the fatigue characteristics of a typical fighter airplane. The primary purpose of this investigation was to obtain fatigue data on full-scale structures for use in designing new aircraft. The aircraft were disassembled into major components: wing, horizontal tail, vertical tail, nose landing gear, and main landing gear. Constant-amplitude and variable-amplitude tests were performed on the various components to determine: (1) the degree of scatter, (2) the effect of cumulative damage and the validity of various cumulative damage hypotheses for full-scale structures, (3) the effect of randomization of the load sequence within a spectrum block, (4) the effect of superimposing landing loads on a flight load spectrum, (5) the effect of prestressing, and (6) the effect of varying the mean and alternating loads. A discussion of the test results and their significance for future design use is included.
Small Specimen Data for Predicting Life of Full-Scale Structures
Authors: Smith Clarence R.
Published: September 2009

This paper presents a method for predicting the fatigue life of a full-scale structure for any combination of loading provided that a single datum point representing the life of the structure for 104 or fewer cycles is known. The only additional information required is stress-strain and S–N data for smcoth axially loaded coupons. An illustrative example of the use of this method is the prediction of lives for tail structures yet to be tested at the Navy Aeronautical Structures Laboratory, Philadelphia, Pa.
Programmed Maneuver-Spectrum Fatigue Tests of Aircraft Beam Specimens
Authors: Mordfin Leonard , Halsey Nixon
Published: September 2009

Constant- and variable-amplitude fatigue tests were conducted on 7075-T6 aluminum alloy built-up beam specimens in bending to study certain aspects of spectrum fatigue. Existing cumulative fatigue damage theories were found inadequate for the dual purpose of predicting spectrum fatigue life and evaluating the effects of individual load levels in a spectrum. However, the observed spectrum fatigue properties were consistent with the measured effects of preloading, overloading, and underloading.

Preloading was beneficial when the preload was considerably greater than the subsequent fatigue loads, and when the preload was applied in the same direction as the fatigue loads. When the preload and the fatigue loads had opposite signs, a reduction in fatigue life resulted. These effects were magnified by the periodic application of overloads.

The periodic application of repeated low loads was ineffectual when applied in the same direction as the fatigue loads. When the spectrum included low loads of negative sign, serious reductions in life resulted.

The most valuable finding, perhaps, was that the fatigue behavior of the beam specimens was similar to that of certain full-scale aircraft structures. It was also found that the fatigue properties of the beam specimens were rather insensitive to variations in testing technique and material.

A pneumatic testing machine and an automatic programmer that were developed for this investigation are described.
The Preparation of Resins for Microscopical Examination by Reflected Light
Authors: Gedney J. I. , Thomas E. J.
Published: September 2009

The wide variety of industrial and experimental resins which have been studied in our laboratory during the past five years has prompted a continuing search for improved methods and media for mounting such materials for micro-scopical examination. The preparatory techniques described were designed to accomodate specimens exhibiting extreme variations in hardness, as well as variations in adhesive qualities, chemical resistance, and wettability. The use of various plastic and resin formulations as mounting media will also be discussed.
Transparent Section Microscopy and High-Speed Cinematography in Photoelasticity Studies
Authors: Wright R. E. , Hall N. W.
Published: September 2009

The resinographer studies the morphology and structure of resins to relate the static properties and dynamic behavior of the resins to their composition and history. Toward this end, he has an ever-increasing list of tools at his command. The study of the photoelastic patterns produced in resins by strain, historically one of the older tools, merits an important place in this list. This paper describes two helpful techniques for the study of photoelastic phenomena in resins.
Measurement of the Surface Properties of Fibers
Authors: Scheier Stanley C. , James Lyons W.
Published: September 2009

Fiber surface properties are important because of their effect on the behavior of yarns and fabrics in textile processing and the performance of the finished product in service. Prominent among these properties are the geometric roughness (profile) of the surface and the frictional characteristics. These are not simply related. Consideration is given to the features characterizing the geometry of a surface and some surface-related factors that may have a bearing on the performance of fibers in processing and in service are outlined.

The developments that have been made at Textile Research Institute (TRI) since 1957 in apparatus and techniques for quantitatively characterizing the surface roughness of fibers are briefly reviewed. The roughness-analyzer system under recent development at TRI, which has some components with the features of electronic computers, is more fully described. Representative results on an animal fiber and on two different samples of a synthetic fiber are presented. Finally, preliminary results are given in the evaluation of newly developed apparatus of high sensitivity for the measurement of surface frictional forces.
Light-Scattering Studies of the Internal Structure of Films and Fibers
Authors: Rhodes M. B. , Stein R. S.
Published: September 2009

The use of light scattering for studying the structure of polycrystalline polymer films has been described by this and other laboratories (1–3). Theory and experimental methods for photographically and photometrically studying the scattering of films have been described. In this paper, currently used techniques and procedures for measuring the scattering of both films and fibers are described, and methods for separating contributions to scattering from density and orientation heterogeneities and voids are proposed. Procedures are given for determining uniaxial and biaxial orientation of superstructure, as are methods for estimating sizes and anisotropy of structure.
The Electron Microscope Applied to a Study of Polyethylene Fibers
Authors: Scott Robert G.
Published: September 2009

Synthetic fibers are prepared for morphological studies either by microtomy or stripping. The usefulness of these techniques is compared, and methods of measuring the quality of the sections is presented. The types of information gained from such preparations are then reviewed.
Phase Microscopy in Resinography
Authors: Morehead F. F. , Felton C. D.
Published: September 2009

Transmission phase microscopy is widely employed by resinographers to clarify the structural details of transparent, colorless resins characterized only by differing refractive indexes. On the other hand, incident phase microscopy is virtually unknown to the resinographer and has been confined primarily to the province of the metallographer. This is unfortunate since the instrumentation can supply unique and useful information for solving many resinographic problems. Illustrative problems in which incident phase microscopy was gainfully employed to obtain a solution are presented.
Fluorescence Microscopy of Resins
Authors: Zieler H. W.
Published: September 2009

The optical property of fluorescence—the emission of visible light by certain resins while they are illuminated with ultraviolet light—can be used to advantage. Objects which do not fluoresce can be stained with fluorescent dyes. The spectral range of wavelengths which cause fluorescence (activation spectrum), as well as the color of the light emitted through fluorescence by the object (emission spectrum), are optical characteristics by means of which the resins may be studied. The optical principle of and instrumentation for fluorescence microscopy, as well as details of special techniques, are described.
Dispersion Staining as Applied to Organic Polymer Identification
Authors: McCrone Walter C.
Published: September 2009

Any transparent substance when mounted in a particular liquid and when properly viewed shows dispersion staining colors. Most transparent substances can be examined in this way in commercially available Cargille index liquids; however, polymers and resins, being essentially liquids, have about the same dispersion curves as the Cargille liquids and show only paint dispersion colors. Other liquids based on cinnamaldehyde show strong dispersion colors with fibers and have been used in this paper.
Microscopical Techniques for the Study of Solid-State Polymerization
Authors: Grabar D. G. , Hsia Chen C. S.
Published: September 2009

Solid-state, radiation-induced polymerization studies are usually conducted by bulk polymerization, followed by separation and gravimetric determination of yield in order to correlate polymerization conditions with results. Microscopical methods of studying some types of these reactions offer many advantages over conventional techniques, and, in addition, yield information not easily obtainable otherwise. Quantitative data relating polymerization rates and behavior to crystal orientation, size, polymorphism, temperature, radiation dose, inhibitors, and solid solutions of isomorphous systems can be obtained. Typical results obtained by X-radiation-induced polymerization of tributylvinylphosphonium bromide, tributylvinylphosphonium iodide, and their solid solutions are presented to illustrate the application of these techniques.
Electron Resinography of a Polyphase Polymeric System
Authors: Botty M. C.
Published: September 2009

The composition of commercial, resinous materials is becoming more complex. There is considerable concern regarding the recognition of functional units in the finished product and their relation with unique physical properties. When investigating polyphase, polymeric systems, it is advantageous to start at low magnification and then proceed to higher levels of magnification, using a variety of microscopical instrumentation and related techniques. Methods which exemplify applications to the systematic study of simple and complex polymeric materials are briefly described and include the following: (1) radiography of the bulk specimen, (2) simple macroprojection of replicas of brittle-fracture surfaces, (3) ultraviolet microscopy for selective differentiation, and (4) electron microscopy for depicting fine detail in thin sections and in replicas.

The application of the electron microscope and the brittle-fracture method will be emphasized to show that in a specific complex polymer system, represented by a commercial, molded impact-resistant material, the morphology of the brittle-fracture surface is directly related to the polyphase character of the polymer. By applying this method in conjunction with supporting instrumentation, the distribution of the particulate, reinforcing phase in a high-impactstrength, molded material was depicted.
Microscopical Studies of Heterogeneous Polymeric Systems
Authors: Claver G. C.
Published: September 2009

During the past decade, the application of microscopical methods and associated techniques has contributed much to the knowledge of heterogeneous polymer systems. Plasticized polymer, pigmented polymer, and polymerpolymer systems have all been examined successfully by the microscopical technique.

Many of these hybrid polymer systems were developed, manufactured, and used extensively, long before any clear understanding of the mechanisms involved in their compounding was obtained. This discussion will bring together some of the technological details of the role of the microscope as it aids our understanding of heterogeneous polymer systems and the morphology — performance relationship of these materials.
Introduction to Color
Authors: Judd Deane B.
Published: September 2009

I am somewhat embarrassed at being referred to as a “color expert.” One of the difficulties of a so-called color expert is that nearly everyone knows a good deal about some phase or other of color and expects the expert to know more. He is supposed to discuss chromophores with the chemist, mordants with the dyer, spectrophotometric curves with the physicist, color specifications with the engineer, and color sensation and perception with the psychologist.
Color Specifications of Transparent Materials
Authors: Francis Scofield
Published: September 2009

The description or specification of the color of transparent materials, as it applies to most industrial materials, is somewhat simpler than many color problems, since any given set of substances is usually somewhat similar in color. Because of that very fact there is somewhat of a tendency to oversimplify it.
Color Standards for Opaque Materials
Authors: Godlove I. H.
Published: September 2009

The definition of color which has been adopted by the A.S.T.M. since 1915 includes a statement that: “Color involves a definite effect produced by the action of light upon the retina of the eye dependent upon the optical composition of the light.” After recognizing that the term is also used in the very different sense meaning material substances (pigments, dyes, etc.), it states that “in specifications it should be recognized that color is primarily a physiological sensation.” This definition is a clear recognition of the fact that the color of an opaque object (sample) depends on three sets of factors: (1) the inherent optical properties of the material of the sample, specifically, the distribution of the light reflected by the sample, wave length for wave length; (2) the nature of the light which falls on the sample, more exactly, the spectral distribution and intensity of the incident radiant energy; and (3) the nature (normalcy, anomaly, etc.) and state of adaptation of the observer's eye at the moment of viewing the sample.
Spectrophotometry and Color Evaluation
Authors: Parker A. E.
Published: September 2009

Spectrophotometry is the measurement of light emitted, transmitted or reflected as a function of wave length. It is not a new field but one which was relatively inactive till the past decade when the development of recording spectrophotometers gave a tremendous impetus to such investigations.