Showing papers on "Ultimate tensile strength published in 1968"
TL;DR: Composite tensile-failure modes, failure load prediction, experimental data and statistical analysis of stress concentration effects are discussed in this article, where failure load and stress concentration effect are discussed.
Abstract: Composite tensile-failure modes, discussing failure load prediction, experimental data and statistical analysis of stress concentration effects
294 citations
TL;DR: Aspirin, like cortisone, reduces the tensile strength of the healing skin wound in rats, and the possible mechanism of action of these anti-inflammatory agents has been discussed.
188 citations
TL;DR: In this paper, it was shown that the microplastic effects produced by pressure of hard, sharp points on glasses do not occur by plastic flow, but by densification, and that the technology of glass cutting is dependent on residual stresses associated with densification.
Abstract: It is proposed as a working hypothesis that the many so-called microplastic effects produced by pressure of hard, sharp points on glasses do not occur by plastic flow, but by densification. An interferometric technique is illustrated, by means of which the existence of densification can readily be demonstrated and its magnitude estimated. It is concluded that the “hardness” number of glasses is best interpreted as a measure of the critical stress for yield by densification; that the hardness number has no necessary relation to tensile strength; and that the technology of glass cutting is dependent on residual stresses associated with densification.
145 citations
TL;DR: A conjunctival flap restored normal healing of the denuded wounds; however, a silicone membrane between the flap and the cornea again drastically reduced wound healing.
Abstract: The tensile strength of central and peripheral penetrating corneal wounds was measured. The gain of strength of central wounds at different time intervals was recorded up to 100 days. Peripheral corneal wounds healed faster than central wounds. Permanent closure of eye lids had no effect on the gain of tensile strength, nor did the presence of a fornix-based conjunctival flap affect the healing of limbal wounds. Absence of corneal epithelium markedly decreased the gain of tensile strength of central wounds. During the first 12 postoperative days, no tensile strength could be measured; after that time a slow healing began. A conjunctival flap restored normal healing of the denuded wounds; however, a silicone membrane between the flap and the cornea again drastically reduced wound healing.
133 citations
TL;DR: In this article, carbon fibres of very high axial stiffness and strength have been prepared at AERE, Harwell, showing that there is an appreciable increase in the apparent modulus of these fibres as a tensile load is applied.
Abstract: FOLLOWING the work of Watt, Phillips and Johnson1, carbon fibres of very high axial stiffness and strength have been prepared at AERE, Harwell. There is an appreciable increase in the apparent modulus of these fibres as a tensile load is applied, and this observation applies both to fibres of type I, heat treated at 2,600° C and with a modulus ∼3.8 × 1012 dynes/cm2 and to those of type II, heat treated at 1,500° C, and with a modulus ∼2.7 × 1012 dynes/cm2 (compare refs. 2 and 3).
115 citations
TL;DR: In this article, an explanation for this dependence and for other variations in the ductile-brittle behavior in terms of the theory and experiments underlying the (Hall-Petch) stress-grain size equations is given.
114 citations
01 Jan 1968
102 citations
TL;DR: In this article, a theory of the tensile strength of powders, incorporating the effect of powder density, particle size distribution and interparticle force, has been developed, which enables the experimental results for different size fractions of each of five materials of different chemical and physical nature to be correlated with the particle size distributions.
93 citations
TL;DR: In this paper, it was shown that the shear index n in the yield locus equation ( τ C n = σ T + 1 where τ = shear stress T = tensile strength σ = normal stress C = cohesion can be correlated with the volume surface mean diameter in microns by means of the general equation n = 1 + B (d) X where B = constant d = volume/surface mean diameter while the tensile weight T is correlated by the equation T = A( ϱ ϱ s )m where A and m = constants ϱ
82 citations
TL;DR: In this paper, a tensile yield criterion that is consistent with both the tensile and simple shear data was proposed, based on a modification of the von Mises yiel.
Abstract: Oriented sheets of polyethylene terephthalate have been deformed in tension and simple shear, with the primary variable as the angle between the tensile stress or the shear stress and the initial draw direction. In tension, deformation bands were observed in all cases, as has been reported previously (Brown and Ward 1968 a), and a clear yiold point was observed in all cases. The stress–strain curves for simple shear on the other hand showed very appreciable changes with the direction of the shear stress, and deformation bands were observed only in certain cases. These qualitative features are consistent with the principles proposed in the previous paper, on the basis of the tensile behaviour. An attempt is made to obtain a yield criterion which is consistent with both the tensile and shear data. It was found that neither a critical resolved shear stress criterion nor this modified by a normal stress term was adequate to explain the tensile yield data. However, a modification of the von Mises yiel...
79 citations
01 Feb 1968
TL;DR: In this article, an investigation was conducted to determine the strength of 26 SINGLE-SPAN SIMPLY Supported REINFORCED CONCRETE DEEP BEAMS.
Abstract: AN INVESTIGATION IS DESCRIBED OF THE BEHAVIOR AND ULTIMATE SHEAR STRENGTH OF 26 SINGLE SPAN SIMPLY SUPPORTED REINFORCED CONCRETE DEEP BEAMS HAVING DIFFERENT DEPTH-SPAN RATIOS. THE BEAMS WERE TESTED BOTH UNDER CONCENTRATED (AT A SINGLE POINT AND TWO POINTS) AND DISTRIBUTED LOADS. BASED ON THE OBSERVED BEHAVIOR AND STRENGTH, AN EQUATION IS PRESENTED FOR PREDICTING THE ULTIMATE SHEAR STRENGTH OF DEEP BEAMS. /AUTHOR/
TL;DR: In this paper, the authors examined the mechanical properties of the heated marble and showed that they are different from those of soils, and that a small amount of confining pressure varies the triaxial strength rapidly, the initial slope of the Mohr envelope being of the order of 65° and the strength finally increasing to over 80% of that of the original rock.
Abstract: Synopsis If coarse grained marble is heated to around 6OO°C the anisotropy of thermal expansion of calcite causes almost complete separation at grain boundaries. The resulting material retains its shape and consists of a mass of crystals in contact, with a porosity of about 4%, very small direct tensile strength and the mechanical analysis and permeability to water of a sand. It may be regarded as a laboratory model of randomly jointed rock and perhaps of bad and broken rock in general. It has frequently been suggested that soil mechanics theory may be applied to such rock. This Paper examines the mechanical properties of the heated marble and shows that they different from those of soils. A small amount of confining pressure varies the triaxial strength rapidly, the initial slope of the Mohr envelope being of the order of 65° and the strength finally increasing to over 80% of that of the original rock. Young's modulus also increases with confining pressure but only to about 30% of that of original rock. ...
TL;DR: In this article, an experimental study of the tensile strength of unidirectional short fiber reinforced plastics is reported, and the data indicate agreement with existing theories as modified to suit plastics.
Abstract: An experimental study of the tensile strength of unidirectional short fiber reinforced plastics is reported. The data indicate agreement with existing theories as modified to suit plastics. The theory is extrapolated to provide a means for computing the strength of a random composite.
01 Apr 1968
TL;DR: In this paper, the authors investigated the effect of different conditions on the likelihood of Morton cracks, such as air temperature, humidity, wind velocity, and wind velocities, and found that the first crack was associated with the transition from the Intensive, PRACTICALLY UNRESTRAINED, LINEAR SHRINKAGE of FRESH MORTAR to the much slower RATE.
Abstract: PLASTIC SHRINKAGE CRACKING OF MORTARS EXPOSED TO DIFFERENT CONDITIONS, AS PREVALENT IN HOT-DRY CLIMATES, WAS INVESTIGATED UNDER CONTROLLED CONDITIONS. THE VARIABLES STUDIED WERE AIR TEMPERATURE AND HUMIDITY, WIND VELOCITY, MORTAR TEMPERATURE, TYPE AND CONTENT OF CEMENT, AND CONSISTENCY. SHRINKAGE, TENSILE STRENGTH AND TENSILE STRESS OF FRESH MORTARS, EVAPORATION AND TIME OF CRACKING WERE MEASURED. WIDTH, DEPTH, AND LENGTH MEASUREMENTS OF THE CRACKS WERE ALSO TAKEN. THE RESULTS CONFIRM THAT RAPID EVAPORATION HAS A PREDOMINANT EFFECT ON PLASTIC SHRINKAGE CRACKING. OTHER CONCLUSIONS ARE THAT PLASTIC SHRINKAGE CRACKING IS NOT A DIRECT FUNCTION OF WATER LOSS, EVAPORATION RATE OR SHRINKAGE, AND THAT SEMIPLASTIC MORTAR DID NOT CRACK UNDER HIGH EVAPORATION CONDITIONS WHICH BROUGHT ABOUT SEVERE CRACKING OF PLASTIC AND WET MORTARS. IT WAS ALSO ESTABLISHED THAT THE FIRST CRACK COINCIDES WITH THE TRANSITION FROM THE INTENSIVE, PRACTICALLY UNRESTRAINED, LINEAR SHRINKAGE OF FRESH MORTAR TO THE MUCH SLOWER RATE DUE TO RESTRAINT ON STIFFENING OF THE MORTAR. /ACI/
TL;DR: In this article, the growth rate of cristobalite was measured on electrically melted quartz glass at 1350° to 1620°C and the observed growth rates were linear with time and were the lowest that have been measured in vitreous silica.
Abstract: It has recently been observed that cristobalite can hetero-geneously nucleate and grow internally in vitreous silica When the glass-crystal composite is cooled to room temperature, β-cristobalite is metastably retained as a result of the large tensile stresses developed during cooling Although these crystals are not obvious, they can be readily observed with a polarizing microscope or polariscope As long as the cristobalite does not transform when cooled to room temperature, repeated increments of crystal growth can be measured on the same growing crystal Crystal growth was measured on electrically melted quartz glass at 1350° to 1620°C The observed growth rates were linear with time and were the lowest that have been measured in vitreous silica The kinetic data agreed with the general form of the crystal growth equation μ= (AΔT)/ν Since the growth is internal and free from surface contamination, the measured rates are considered to be very near the intrinsic rates for the material
01 Feb 1968
TL;DR: In this paper, the authors conducted a study on the behavior of ASPHALT CEMENTs in three types of failure modes: burst failure, flow failure, and bottleneck failure.
Abstract: THE REPORTED STUDY WAS CONDUCTED TO EXTEND THE KNOWLEDGE OF THE BEHAVIOR OF ASPHALT CEMENT IN THIN FILM SUBJECTED TO TENSILE STRESSES. THE TENSILE BEHAVIOR AND FAILURE CHARACTERISTICS OF 11 ASPHALT CEMENTS IN THIN FILMS WERE STUDIED. VARIABLES IN THE STUDY INCLUDED: (1) FILM THICKNESS, (2) RATE OF DEFORMATION, (3) TEMPERATURE, (4) CONSISTENCY, AND (5) SOURCE OF THE BITUMINOUS MATERIAL. A DEFINITE RELATIONSHIP WAS FOUND TO EXIST BETWEEN THE TENSILE PROPERTIES OF A GIVEN ASPHALT CEMENT AND THE FILM THICKNESS OF THE SPECIMEN. THE TENSILE STRENGTH OF ASPHALT CEMENTS IN THIN FILMS IS SIGNIFICANTLY INFLUENCED BY THE TEST RATE OF DEFORMATION AND/OR THE TEST TEMPERATURE. THE CONSISTENCY OF THE ASPHALT CEMENT HAS A SIGNIFICANT INFLUENCE ON TENSILE STRENGTH. THE SOURCE OF THE ASPHALT CEMENT MAY INFLUENCE THE TENSILE STRENGTH OF THE MATERIALS. IT APPEARS THAT THE ASPHALTENE CONTENT OF ASPHALT CEMENTS OBTAINED FROM A GIVEN SOURCE MAY HAVE A SIGNIFICANT INFLUENCE ON THE CONSISTENCY OF THE MATERIALS AND THUS, ON THE TENSILE STRENGTH. THREE MODES OF FAILURES WERE OBSERVED IN THE ASPHALT SPECIMENS. THE RANGE OF FILM THICKNESS EXHIBITING EACH FAILURE MODE WAS DEPENDENT UPON SPECIFIC COMBINATIONS OF: (1) ASPHALT SOURCE AND CONSISTENCY, (2) RATE OF DEFORMATION, AND (3) TEMPERATURE. THE OBSERVED MODES OF FAILURE WERE REFERRED TO AS: BRITTLE FRACTURE, FLOW FAILURE AND INTERMEDIATE FAILURE OR TENSILE RUPTURE. SPECIMENS WHICH EXHIBITED THE BRITTLE MODE HAD FAILURE SURFACES WHICH WERE SMOOTH AND GLASSY IN APPEARANCE. SPECIMENS WHICH EXHIBITED FLOW FAILURE USUALLY EXHIBITED A FAILURE SURFACE FORMED BY EXCESSIVE NECKING AND INTERNAL FLOW OF THE SPECIMEN. THE INTERMEDIATE MODE FAILURE SURFACE EXHIBITED A COMBINATION OF MULTIPLE DEPRESSIONS AND MULTIPLE RIDGES. THE LIMIT OF BRITTLE FRACTURE AND THE LIMIT OF FLOW FAILURE ARE: FUNCTION OF TEMPERATURE, RATE OF DEFORMATION, AND ASPHALT CONSISTENCY. THE TYPE OF FAILURE THAT OCCURS IN THIN FILMS OF BITUMINOUS MATERIAL SUBJECTED TO TENSILE STRESSES CAN GENERALLY BE CLASSIFIED AS A COHESIVE FAILURE RATHER THAN AN ADHESIVE FAILURE. A CONSTANT RATE OF LOADING TEST APPEARS TO BE A MORE DESIRABLE TEST METHOD THAN A CONSTANT RATE OF DEFORMATION TEST FOR DETERMINING ASPHALT CEMENT BEHAVIOR CHARACTERISTICS. BITUMINOUS MATERIALS IN THIN FILMS WHEN SUBJECTED TO TENSILE STRESSES EXHIBIT A CAVITATION PHENOMENA AND THE VOLUME OF THE SPECIMEN APPEARS TO INCREASE. THE AMOUNT OF DEFORMATION TO FAILURE APPEARS TO BE PARTIALLY DEPENDENT UPON FILM THICKNESS.
Patent•
27 May 1968TL;DR: Anisometric compressed and bonded knitted wire mesh composites are provided in this paper which comprise a plurality of sheets of knitted mesh, superimposed at random orientation with respect to each other, compressed or densified to a voids volume within the range from about 10 to about 90 percent, and bonded together.
Abstract: Anisometric compressed and bonded knitted wire mesh composites are provided which comprise a plurality of sheets of knitted wire mesh, superimposed at random orientation with respect to each other, compressed or densified to a voids volume within the range from about 10 to about 90 percent, and bonded together. The sheets are taken in sufficient number, usually at least five and preferably 10 or more, and as much as 1,000 or more, to form a self-supporting relatively non-resilient composite of high tensile strength and high breaking strength having an average pore diameter of less than 200 microns, and preferably less than 100 microns, that is relatively uniform in any unit area of the surface, and having an anisometric porosity, the through pores extending crosswise of the sheet greatly exceeding in number the through pores extending laterally of the sheet, which latter pores can be reduced virtually to zero in a highly compressed composite. The composite is formed by superimposing a plurality of knitted wire mesh sheets, annealing the composite to avoid wire breakage during later processing, compressing the composite to the desired density and anisometricity by application of pressure in a direction approximately perpendicular to the plane of the layers of the composite, and bonding the sheet layers and the wire filaments of the sheets together at their points of contact and/or crossing. The bonding holds the composite at the selected density, prevents relative movement of the wires in the composite, and in conjunction with the multilayer structure imparts the self-supporting nonresilient characteristic, together with high tensile strength and high breaking strength.
TL;DR: In this paper, a complete theoretical and experimental description of the tensile strength relationship in the whole moisture range has been given, which can be used to confirm or improve the Rumpf equation.
Abstract: IN several communications1–4 on the tensile strength of granular materials bound by liquids, authors have tried to confirm or improve the equation of Rumpf5. At the Institute of Mechanical Process Engineering of the University of Karlsruhe, where the first measurements of the tensile strength of moist agglomerates started in 1957, investigations have recently led to a complete theoretical and experimental description of the tensile strength relationship in the whole moisture range.
TL;DR: In this article, the phenomological fracture properties of glass bead filled polyphenylene oxide composites were investigated and yield strength and Young's modulus were obtained as a function of volume fraction of filler using standard microtensile testing techniques.
Abstract: The phenomological fracture properties of glass bead filled polyphenylene oxide composites were investigated.Yield strength and Young's modulus were obtained as a function of volume fraction of filler using standard microtensile testing techniques. Fracture toughness was measured using double edge notched tensile bars. The effects of adhesion were studied by using untreated and A-1100 silane-treated glass beads. The nature of the fracture surfaces was observed by use of an optical microscope, a scanning electron microscope and a transmission electron microscope.It was found that the fracture toughness of these materials de creased by increasing the filler content and by improving the adhesion. In general, an increase in strength and stiffness was accompanied by a decrease in toughness.The fractographic studies gave a detailed mapping of the frac ture front as it propagated through the material. Fracture occurred in two stages. The initial stage was a region of stable crack growth accompanied by, crazing, ...
TL;DR: The physical and mechanical properties of block copolymers are compared and correlated with the corresponding random copolymer as discussed by the authors, and it is shown that block copolerant polymers are superior to those of non-polymer polymers.
Abstract: Physical and mechanical properties of block copolymers are compared and correlated with the corresponding random copolymers. The important properties of melting point, transition temperatures, tensile strength, modulus, and elastic properties depend upon the structural arrangement of the molecular units comprising the polymer strecture. All available data suggest overwhelmingly that properties of block copolymers are superior to those of random copolymers. A block copolymer can have properties characteristic of each of the homopolymers from which it is derived as well as a set of properties due to the polymer strcture as a whole. Block copolymers have an advantage over random copolymers in that a crystalline polymer can be modified without significant reduction of its melting point, modulus, tensile strength, and elastic properties, and by suitable selection of a second component it affords a means of “building in” a particular property.
TL;DR: Transgranular stress corrosion cracks are formed in Ti-5Al-2.5Sn alloy immersed in a 3 percent NaCl aqueous solution when tensile specimens are dynamically strained over a narrow range of...
Abstract: Transgranular stress corrosion cracks are formed in Ti-5Al-2.5Sn alloy immersed in a 3 percent NaCl aqueous solution when tensile specimens are dynamically strained over a narrow range of ...
TL;DR: In this article, an alloy of composition 24% Ni, 17% Cr, 2% Ti (bal. Fe) was heat-treated to produce precipitation of the γ′ (ordered Ni 3 Ti)-phase in austenite, and proof stressageing time curves were obtained for specimens aged at 725 and 750°C.
01 Jul 1968
TL;DR: In this paper, the authors investigated the effect of CURING and DRYING environments on the strength of light weight and normal weight and found that only minor changes in the SPLITTING strength were found as the relative humidity increased from 75 to 10 percent.
Abstract: THE SPLITTING TENSILE STRENGTHS OF LIGHTWEIGHT AND NORMAL WEIGHT CONCRETES WERE INVESTIGATED IN TWO TEST SERIES WHICH DEALT WITH THE EFFECTS OF THE CURING AND DRYING ENVIRONMENTS. THE FIRST SERIES SHOWED THAT THE DURATION OF THE INITIAL MOIST CURING PERIOD PRIOR TO DRYING AT 50 PERCENT RELATIVE HUMIDITY HAD LITTLE EFFECT ON THE SPLITTING STRENGTH. WHILE THERE WAS A LOSS OF SPLITTING STRENGTH FOR THE LIGHTWEIGHT CONCRETE EARLY IN THE DRYING PERIODS, CONTINUED STORAGE IN THE DRYING ATMOSPHERE LED TO CONSIDERABLE GAIN IN THE SPLITTING STRENGTHS. IN THE SECOND SERIES, CONCRETES WERE SUBJECTED TO DRYING FOR 21 DAYS AT DIFFERENT LEVELS OF RELATIVE HUMIDITY AFTER INITIAL MOIST CURING FOR 7 DAYS. ONLY MINOR CHANGES OF SPLITTING STRENGTH WERE FOUND AS THE RELATIVE HUMIDITY VARIED FROM 75 TO 10 PERCENT. /AUTHOR/
Journal Article•
TL;DR: In this paper, the authors discuss the importance of the TENSILE CHARACTERISTICS of the SUBBASE of RIGID PAVEMENTs can be DEMONSTRATED BOTH from the ORETICAL CONSIDERATIONS and from FIELD OBSERVATIONS information on the TENSILE BEHAVIOR and PROPERTIES of TREATED and UNTREATED SUBBS MATERIALs is limited.
Abstract: THE IMPORTANCE OF THE TENSILE CHARACTERISTICS OF THE SUBBASE OF RIGID PAVEMENTS CAN BE DEMONSTRATED BOTH FROM THEORETICAL CONSIDERATIONS AND FROM FIELD OBSERVATIONS INFORMATION ON THE TENSILE BEHAVIOR AND PROPERTIES OF TREATED AND UNTREATED SUBBASE MATERIAL IS LIMITED PRIMARILY BECAUSE OF THE LACK OF A SATISFACTORY TENSILE TEST ON THE BASIS OF A LITERATURE REVIEW CONCERNED WITH TENSILE TESTING, IT WAS CONCLUDED THAT OF THE CURRENTLY AVAILABLE TENSILE TESTS THE DIRECT TENSILE TEST HAS THE GREATEST POTENTIAL FOR THE EVALUATION OF THE TENSILE PROPERTIES OF HIGHWAY MATERIALS THIS PAPER DISCUSSES TENSILE TESTING, THEORY OF THE INDIRECT TENSILE TEST, AND FACTORS AFFECTING THE TEST IN ADDITION, THE RESULTS OF A LIMITED TESTING PROGRAM TO EVALUATE THE EFFECT OF SUCH FACTORS AS COMPOSITION AND WIDTH OF LOADING STRIP, TESTING TEMPERATURE, AND LOADING RATE ON THE INDIRECT TENSILE TEST PARAMETERS OF STRENGTH, VERTICAL FAILURE DEFORMATION, AND A LOAD VERTICAL FAILURE DEFORMATION MODULUS FOR ASPHALT-STABILIZED AND CEMENT-TREATED MATERIALS ARE INCLUDED ON THE BASIS OF THE LITERATURE REVIEW AND EXPERIMENTAL INVESTIGATION, IT IS RECOMMENDED THAT THE INDIRECT TENSILE TEST BE USED FOR EVALUATING THE TENSILE PROPERTIES OF STABILIZED MATERIALS AND THAT THE TEST BE CONDUCTED UTILIZING A 10-IN WIDE STAINLESS STEEL LOADING STRIP, A LOADING RATE OF 2 IN/MIN, AND A TESTING TEMPERATURE OF 77F /AUTHOR/
01 Jan 1968
TL;DR: Composite tensile failure modes, failure load prediction, experimental data and statistical analysis of stress concentration effects are discussed in this article, where failure load predictions and failure load models are discussed.
Abstract: Composite tensile failure modes, discussing failure load prediction, experimental data and statistical analysis of stress concentration effects
TL;DR: In this paper, the transcrystalline stress corrosion cracking of austenitic chrome-nickel steel in hot chloride solutions was investigated, and the results showed that, depending on the test conditions, the relationship between stress and service life can be formally described by an exponential function.
Abstract: Zur weiteren Aufklarung verschiedener Einzelheiten bei der transkristallinen Spannungsriskorrosion austenitischer Cr-Ni-Stahle wurden Zugversuche mit dem Werkstoff X 5 Cr Ni 189 in heisen, hochkonzentrierten MgCl2-Losungen durchgefuhrt. Ausenstromlose Versuche ergaben, das die Spannungsabhangigkeit der Standzeit je nach den Versuchsbedingungen formal durch eine Potenz- oder Expotentialfunktion beschrieben werden kann. Bis zu Spannungen von 2 kp · mm−2 hinab war keine Grenze zu beobachten, unterhalb derer Spannungsriskorrosion uberhaupt nicht auftritt.
Durch potentiostatische Halteversuche bei verschiedenen Spannungen konnte ein Potential-Zugspannungs-Standzeit-Diagramm aufgestellt werden. Das Auftreten der Spannungsriskorrosion ist zu positiven Potentialen hin immer starker von Lochfras begleitet wird.
Dehnungsmessungen wahrend der Versuche lieferten auf zerstorungsfreiem Wege ein hinreichend exaktes Kriterium fur die Aufteilung der Gesamtversuchszeit in Inkubations- und Reisperiode. Die Lange der Inkubationsperiode hangt sowohl von der Hohe der Zugspannung als auch vom Probenpotential ab.
Fur die Reisperiode ergab sich das die Wachstumsgeschwindigkeit der Risse formal der jeweils am Risgrund herrschenden Spannung proportional ist Die Proportionalitatskonstante ist wiederum eine lineare Funktion des Probenpotentials. Durch Extrapolation last sich das Grenzpotential ermitteln, unterhalb dessen Spannungsriskorrosion nicht auftreten kann.
Elektrochemische Messungen ergaben, das in den gepruften Losungen die Wasserstoffionenreduktion der masgebliche kathodische Teilvorgang ist. Der untersuchte Werkstoff ist stabil passiv; sein Ruhepotential im gesammten Zustand liegt an der unteren Grenze des Lochfrasbereiches. Zugspannungen bzw. die durch sie bedingten Verformungen verschieben das Grenzpotential fur die heterogene Korrosion zu negativen Werten.
Investigations into the transcrystalline stress corrosion cracking of austenitic chrome-nickel steel in hot chloride solutions
To obtain a further clarification of various details in respect of the transcrystalline stress corrosion cracking of austenitic Cr-Ni steels, tensile strength tests were carried out with X 5 CrNi 18 9 in hot, highly concentrated MgCl2, solutions. Tests without extraneous currents showed that, depending on the test conditions, the relationship between stress and service life can be formally described by an exponential function. Down to stresses of 2 kg/mm2, there was no discernible threshold below which stress corrosion cracking does not occur at all.
By means of potentiostatic holding tests at different stresses, it was possible to plot a potential/tensile stress/service life diagram. The occurrence of stress corrosion cracking shows a distinct threshold on the side of negative potentials; on the side of positive potentials, however, the occurrence of stress corrosion cracking is increasingly accompanied by pit corrosion.
Strain measurements carried out during the tests yielded, in a non-destructive way, a sufficiently exact criterion for the division of the total test period into incubation period and tearing period. The length of the incubation period depends on the tensile stress as well as on the specimen potential.
As regards the tearing period it was found that the growth rate of the cracks is formally proportional to the stress at the bottom of the crack. The proportionality constant, in its turn, is a linear function of the test potential. By means of extrapolation, it is possible to deter-mine the minimum potential below which stress corrosion cracking can no longer occur.
Electro-chemical measurements showed that, in the tested solutions, it is the hydrogen reduction which represents the vital catholic part-process. The tested material is in the state of passive stability; its rest potential in the non-stressed condition lies at the lower threshold of the pit corrosion range. Tensile stresses, or the deformations caused by them, have the effect of shifting the minimum potential for heterogeneous corrosion into the negative range.
TL;DR: In this paper, the effect of fiber/fibre interaction on the stress distribution and tensile strength of discontinuous, aligned fiber composites was investigated. But the authors focused on the tensile properties of the fiber composite.
Abstract: This paper is concerned with the effect of fibre/fibre interaction on the stress distribution and tensile strength of discontinuous, aligned fibre composites. The stress distribution for a rationalized composite is derived which shows good agreement with an experi ment on a large scale model fibre composite. Expressions are also derived for the tensile strength of the rationalized composite, and these appear to provide reasonable approximations for the strength of practical fibre composites.
TL;DR: In this paper, it was shown that annealing thin films at temperatures near the glass transition, Tg, causes these nodules to enlarge and they are thought to be precursors of spherulites.
Abstract: Electron microscopic investigations have revealed that the surface of poly(bisphenol-A-carbonate) contains nodular units ca. 125 A in size. It is shown that annealing thin films at temperatures near the glass transition, Tg, causes these nodules to enlarge. Tensile deformation results in the nodules breaking apart as the film elongates; however, if the sample has been annealed prior to stretching, the nodules appear to rearrange as shear occurs between them. It is suggested that each nodule represents a region containing a near-crystalline degree of molecular order. Featherlike structures, many microns in extent, are also observed to form in thin films annealed near the glass transition. They are thought to be precursors of spherulites. By annealing slightly above the glass transition, the spherulite development sequence has been observed to involve the creation of lamellae from initially broad, radiating arms.
TL;DR: In this paper, the authors studied the mechanics of rupture propagation in blended yarns and found that the rupture propagates catastrophically upon tensile failure of a few low-elongation fibers.
Abstract: Our studies of the mechanics of rupture of blended yarns have been concerned primarily with the transfer of stresses from the fiber component which breaks first to the component which breaks last. The accepted practice of blending fibers with widely differing elongationsto-break makes it important to understand the nature of rupture propagation in blended textile yarns. For if the rupture propagates catastrophically upon tensile failure of a few low-elongation fibers, then the yarn, as