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Showing papers on "Tensile testing published in 1969"


Journal ArticleDOI
01 Aug 1969
TL;DR: In this article, the authors report that the BIAXIAL TENSILE STRENGTH of CONCRETE is APPROXIMATELY EQUAL to its UNIAXial TENSION STRENGTH.
Abstract: EXPERIMENTAL STUDIES INTO THE BIAXIAL STRENGTH OF CONCRETE ARE REVIEWED AND TECHNICAL DIFFICULTIES ENCOUNTERED IN THE DEVELOPMENT OF A SUITABLE TEST SETUP ARE DISCUSSED. A NEW TESTING APPARATUS IS DESCRIBED WHICH ALLOWS TESTING OF CONCRETE SPECIMENS UNDER VARIOUS BIAXIAL STRESS STATES. RESULTS OF AN INVESTIGATION FOR WHICH THIS EQUIPMENT WAS USED ARE REPORTED. THE TEST DATA INDICATE THAT THE STRENGTH OF CONCRETE UNDER BIAXIAL COMPRESSION IS ONLY 16 PERCENT LARGER THAN UNDER UNIAXIAL COMPRESSION. TESTS IN THE REGION OF COMBINED COMPRESSION AND TENSION CONFIRMED PREVIOUSLY OBTAINED DATA. THE BIAXIAL TENSILE STRENGTH OF CONCRETE IS APPROXIMATELY EQUAL TO ITS UNIAXIAL TENSILE STRENGTH. /ACI/

1,012 citations


Journal ArticleDOI
TL;DR: In this paper, the authors conducted extensive laboratory tests to study hydraulic fracturing initiation in porous-permeable materials under open-hole conditions and found that the resulting critical pressures were clearly dependent upon the rate of pressurization, in accordance with theories of strength which show an inverse relationship between the time a load is applied to a sample and its tensile strength.
Abstract: Extensive laboratory tests have been conducted to study hydraulic fracturing initiation in porous-permeable materials under open-hole conditions. Hydrostone specimens containing a vertical central hole simulating a well bore were subjected to unequal 3-dimensional compressive loadings, parallel and perpendicular to the hole axis. Fractures due to internal pressurization of the model well bore were always tensile ruptures. Initiation pressures were close to values predicted theoretically for porous-permeable materials. Fractures were always either vertical, normal to the smaller horizontal compressive load, or horizontal initiated close to the end of the packed-off region. Three pressurizing rates (6 psi/sec, 60 psi/sec, 600 psi/sec) were tested on hydrostone 32/100, cubical samples. The resulting critical pressures were clearly dependent upon the rate of pressurization, in accordance with theories of strength which show an inverse relationship between the time a load is applied to a sample and its tensile strength. (13 refs.)

151 citations


Journal ArticleDOI
TL;DR: In this article, the authors applied the plastic instability approach to the tensile behavior of a continuous fiber composite and showed that the combination of two components with different strengths and degrees of work-hardening produces a new material with a new degree of workhardening, which may be determined by the present analysis.
Abstract: The plastic instability approach has been applied to the tensile behaviour of a continuous fibre composite. It is shown that the combination of two components with different strengths and degrees of work-hardening produces a new material with a new degree of work-hardening, which may be determined by the present analysis. Expressions for the elongation at rupture and the strength of a composite have been obtained and the results of the calculation are compared with some experimental data.

133 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented results of ring tests on a gympsum plaster, with and without limestone inclusions, with the emphasis on small hole sizes, and showed that the tensile strength varies within the ring test between two constant values.

83 citations


Journal ArticleDOI
TL;DR: In this paper, the authors measured the ductility of Type 304L and Type 310 stainless steel as measured by tensile elongation and showed that the amount of hydrogen absorbed by the stainless steel foils can significantly reduce the tensile strength and ductility.
Abstract: The ductility of Type 304L and Type 310 stainless steel as measured by tensile elongation can be reduced substantially when high contents of hydrogen are absorbed. Cathodic charging of thin stainless steel foils severely reduced the foils' ductility and tensile strength. Only a very thin surface layer was damaged by cathodically charged hydrogen because the hydrogen diffused very slowly into the metal, the relative loss of ductility caused by cathodic charging of cold worked material depended on the amount of martensitic phases present. The maximum relative loss of ductility was in material that had been cold strained at −196 C (−320 F) and contained large amounts of the martensitic phases (alpha prime, body-centered cubic and epsilon, hexagonal close-packed). The loss of ductility was related to the width and depth of surface cracks observed in mechanically tested hydrogenated material.

72 citations



Journal ArticleDOI
R.R. Rizzo1
TL;DR: In this article, an analytical investigation of gripping effects on the off-axis tensile test results for flat specimens is made, and the results support the findings of [1] in demonstrating that length/width ratio and type of constraint can significantly modify the intended uniform stress/strain fields in the subject test.
Abstract: An analytical investigation has been made of gripping effects on the off-axis tensile test results for flat specimens. It is an extension of the earlier work of Pagano and Halpin [1] and aims at establishing approxi mate bounds on the accuracy of the subject test. Considered are the cases of rigid clamping with and without end rotation for selected properties which are typical of glass, boron and graphite composites. Solutions of the corresponding mathematical models are effected numerically, utilizing a computerized finite-element approach.The results support the findings of [1] in demonstrating that length/width ratio and type of constraint can significantly modify the intended uniform stress/strain fields in the subject test. Despite this adverse effect, the analysis suggests that if strain measurements can be properly recorded, reasonably accurate test results should be obtain able for even small length/width specimens. Moreover, though the numerical results lack the generality of closed-form solution...

46 citations


Journal ArticleDOI
TL;DR: In this paper, the relationship between the tensile stress and the mesh size tm of the oxide network in a plane can be expressed by the equation σ = σ 0 + k · t m −1 2 where k is a constant independant of mesh size.

28 citations


01 Mar 1969
TL;DR: The InDIRECT TENSILE TEST as discussed by the authors was used to evaluate the effect of different factors on the performance of ASPHALT-TREATED MATERIALs.
Abstract: THE INDIRECT TENSILE TEST WAS USED TO EVALUATE FACTORS WHICH AFFECT THE TENSILE PROPERTIES OF ASPHALT-TREATED MATERIALS. EIGHT FACTORS WERE EVALUATED AT TWO LEVELS IN A 1/4 REPLICATE OF A FULL FACTORIAL STATISTICAL DESIGN. THE FACTORS INVESTIGATED INCLUDED AGGREGATE TYPE, AGGREGATE GRADATION, ASPHALT VISCOSITY, ASPHALT CONTENT, COMPACTION TYPE, MIXING TEMPERATURE, COMPACTION TEMPERATURE, AND CURING TEMPERATURE. THE TEST PARAMETERS USED AS INDICATORS OF THE MATERIALS' TENSILE PROPERTIES WERE INDIRECT TENSILE STRENGTH AND HORIZONTAL FAILURE DEFORMATION. AN ANALYSIS OF VARIANCE WAS CONDUCTED TO DETERMINE THE SIGNIFICANCE OF THE EFFECTS OF ALL MAIN FACTORS, TWO-WAY INTERACTIONS, AND CERTAIN THREE-WAY INTERACTIONS ON THE TEST PARAMETERS. TABLES SHOWING THE ORDER OF SIGNIFICANCE AS WELL AS PLOTS INDICATING THE EFFECTS OF THOSE FACTORS AND INTERACTIONS SIGNIFICANT AT AN ALPHA LEVEL OF 0.01 ARE PRESENTED IN THE ACTIONS SIGNIFICANT AT AN ALPHA LEVEL OF 0.05 OR GREATER TO OBTAIN PREDICTIVE EQUATIONS FOR BOTH OF THE TEST PARAMETERS. THESE REGRESSION EQUATIONS ALONG WITH THEIR REGRESSION COEFFICIENTS AND STANDARD ERRORS OF ESTIMATE ARE PRESENTED IN THE REPORT. /AUTHOR/

20 citations


Journal ArticleDOI
TL;DR: In this article, a statistical model for the tensile fracture of parallel fiber composites is based on a stress criterion for crack propagation, and the stresses in fiber which surround a crack nucleus are evaluated and the number and size of such nuclei are evaluated statistically.
Abstract: A statistical model for the tensile fracture of parallel fiber composites is based on a stress criterion for crack propagation. The stresses in fiber which surround a crack nucleus are evaluated and the number and size of such nuclei are evaluated statistically. Failure is predicted when, statistically, a new break is expected at any crack nucleus. The predictions of this model are in good agreement with measured tensile strength, the variation of strength with size, the variability of tensile fracture srength, the very small creep strain, and the observed mechanism of fracture of fiberglass composites.

19 citations


Journal ArticleDOI
TL;DR: In this paper, a special-purpose analog computer has been assembled and used online to process the thermal and mechanical data obtained in high speed tensile testing, and rough first-order room temperature crystallization kinetics curves were obtained having time constants of 50-60 msec in the range of 400-540% extension.
Abstract: Stress-induced crystallization in a rapidly stretched natural rubber gum vulcanizate has been studied using thermal techniques to follow the development of crystallinity. A special-purpose analog computer has been assembled and used online to process the thermal and mechanical data obtained in high speed tensile testing. Roughly first-order room temperature crystallization kinetics curves were obtained having time constants of 50–60 msec in the range of 400–540% extension. While the rate of this rapid, presumably primary crystallization appears rather insensitive to elongation in this limited range, the extent of crystallization at 400 msec increases smoothly from zero at 340% elongation to around 18% at 540% elongation. It is shown that our high-speed tensile tester can stretch this vulcanizate fast enough that most of the crystallization takes place after extension has been completed. Stress—strain curves obtained at this high rate are compared with those obtained at lower rates where crystalli...

Journal ArticleDOI
TL;DR: In this paper, a hydraulic rams actuated by air-hydraulic pumps exert completely independent tensions on cruciform test pieces through spherical bushes, one face of which has to be unobstucted throughout the test.
Abstract: The machine is intended for a flat-plate testpiece, one face of which has to be unobstucted throughout the test. Plates up to 36 in long, 27 in wide, and 3/4 in thick can be accommodated.Hydraulic rams actuated by air-hydraulic pumps exert completely independent tensions on cruciform test pieces through spherical bushes.Satisfactory direct-load readings were obtained form pressure gauges.

01 Jan 1969
TL;DR: In this paper, the authors discuss some results obtained in a study of RESUDUAL STRESS and column strength of rolled and wELDed shapes, and discuss the different ASPECTS COVERED in this study.
Abstract: THE DISCUSSION SUMMARIZES SOME RESULTS OBTAINED IN A STUDY OF RESUDUAL STRESSES AND COLUMN STRENGTH OF ROLLED AND WELDED SHAPES. THE DIFFERENT ASPECTS COVERED INCLUDE: (1) STATISTICAL VARIATION OF YIELD STRENGTH IN MILL TESTS, (2) COMPARISON OF TENSION TESTING TECHNIQUES, (3) VARIATION OF YIELD STRENGTH OVER THE CROSS SECTION OF PLATES AND SHAPES, (4) INFLUENCE OF STRAIN RATE UPON YIELD STRENGTH, (5) VARIATION OR SCATTER OF RESIDUAL STRESS AS MEASURED IN MEMBERS OF SAME SIZE AND MANUFACTURING CONDITIONS, AND (6) SCATTER OF RESIDUAL STRESS IN VARIOUS SECTIONS ALONG A PARTICULAR MEMBER. /AUTHOR/

Journal ArticleDOI
TL;DR: In this paper, the tensile test of unnotched and round specimens in the liquid tin, lead, zinc and bismuth bath was carried out with an Instron type testing machine in order to investigate the susceptibility of a mild steel to liquid metal embrittlement for which some inconsistent results had been reported among investigators.
Abstract: The tensile test of unnotched and round specimens in the liquid tin, lead, zinc and bismuth bath was carried out with an Instron type testing machine in order to investigate the susceptibility of a mild steel to liquid metal embrittlement for which some inconsistent results had been reported among investigators. In the present paper, in this context, various effects of test conditions on liquid metal embrittlement were studied.The results obtained are summarized as follows;(1) Propensity to liquid metal embrittlement is influenced by the test temperature, for which the optimum temperature exists.(2) The embrittlement is greatly affected by the strain rate, for which the optimum rate also can be found.(3) It is not considered that liquid metal embrittlement is essentially influenced by the holding time at the testing temperature before straining.(4) The embrittlement by liquid zinc is very sensitive to the surface roughness of the specimen, that may be ascribed to the notch effect.(5) The embrittlement by liquid tin has no relation with the diameter of specimen or the ratio of surface area to volume of test specimen.(6) Liquid bismuth does embrittle the mild steel.Consequently, it is not considered that the embrittlement in liquid metal of mild steel is merely controlled by the chemical diffusion that depends upon the acting time and temperature.


Journal ArticleDOI
TL;DR: In this article, the effect of fillers on the ultimate tensile strength of polyethylene composites is discussed and the usual two-phase model is inadequate to describe filler-polyethylene composite when the filler has a high surface energy.
Abstract: The strain energy and stress concentrations in filled polyethylene are analyzed and the effect of fillers on the ultimate tensile strength of these composites is discussed It is shown that the usual two‐phase model is inadequate to describe filler‐polyethylene composites when the filler has a high surface energy Since a high surface energy substrate is known to generate a transcrystalline region, at the polymer matrix‐filler interface, which differs mechanically from the bulk polymer, a three‐phase model is proposed and analyzed The agreement between theory and experiment lends credence to the three‐phase model

Journal ArticleDOI
TL;DR: Tape-closed wounds with cut panniculus muscle developed a higher tensile strength than sutured wounds, probably brought about by tension on the maturing collagen fibers, apparently a different collagen material was being developed.

01 Jan 1969
TL;DR: In this article, a unique and accurate device aimed specifically at tension testing of brittle materials has been devised, which effectively minimizes in a simple manner parasitic bending stresses that usually arise in conventional tension testing.
Abstract: : A unique and accurate device aimed specifically at tension testing of brittle materials has been devised. This device effectively minimizes in a simple manner parasitic bending stresses that usually arise in conventional tension testing. The text gives the reasons for minimization of these errors as well as the results of an experimental test program which showed that these errors were small. A comparison of the results obtained from this proposed method of testing to those already in practice is included in this report. (Author)

Patent
28 Feb 1969

01 May 1969
TL;DR: In this paper, the design, operation, and purpose of a new biaxial tensile test instrument to measure the stress-strain behavior of fabrics is discussed, and the test results on three air-supported tent fabrics performed with the new test instrument are presented.
Abstract: : This report discusses the design, operation, and purpose of a new biaxial tensile test instrument to measure the stress-strain behavior of fabrics. The report also presents the stress-strain test results on three air- supported tent fabrics performed with the new test instrument. A correlation and comparison is made between these data and previous work performed with other tensile test equipment.

01 Sep 1969
TL;DR: In this article, a drop weight test machine was developed which can subject specimens to tensile strain rates of 50/sec Dynamic and static tensile stress-strain curves were obtained for commercially pure aluminum, high purity aluminum, alpha-brass, and an epoxy resin.
Abstract: : A drop weight test machine was developed which can subject specimens to tensile strain rates of 50/sec Dynamic and static tensile stress-strain curves were obtained for commercially pure aluminum, high purity aluminum, alpha-brass, and an epoxy resin The results showed that all these materials are rate sensitive in that the dynamic curves differed significantly from the static ones The results are discussed in relation to those obtained by other investigators (Author)

Journal ArticleDOI
TL;DR: In this article, a tensile test for metallic materials under constant high hydrostatic pressure up to 15,000kg/cmcm2 has been designed and constructed, where two plungers each of diameter of 30mm are fixed in a high pressure cylinder, held fast together so as to keep the pressure inside the cylinder constant, and that the specimen which is attached to the lower plunger will be pulled by the shift of position of the cylinder to these plungers.
Abstract: An apparatus for tensile testing of metallic materials under constant high hydrostatic pressure up to 15000kg/cmcm2 has been designed and constructed. This apparatus is so devised that during the tensile test two plungers each of diameter of 30mm are fixed in a high pressure cylinder, held fast together so as to keep the pressure inside the cylinder constant, and that the specimen which is attached to the lower plunger will be pulled by the shift of position of the cylinder to these plungers. The fluctuation in pressure during the test is so small that it is not detectable by the ordinary manganin pressure gauge. The change of the pressure is workable during the test, in case it is desirable by using a couple of Bridgman type tensile yokes and making the lower plunger, which is released of the specimen, shift its position by itself. In this case the fluctuation in pressure increases, but it remains within 100kg/cmcm2. The load is measured by a magnetostrictive load cell set in the high pressure chamber, The ongation of the specimen is obtained by measuring the movement of the cylinder. The dimension of the specimen is 3-5mm in diameter and 30-40mm in gauge length. The maximum load applicable to the specimen is 1000kg.

Journal ArticleDOI
TL;DR: In this article, a device is described with which tensile test specimens may be irradiated under a well-defined tensile stress with fast neutrons in low temperature irradiation facilities in order to stabilize the dislocation arrangement present in the stress-applied state.
Abstract: A device is described with which tensile test specimens may be irradiated under a well-defined tensile stress with fast neutrons in low temperature irradiation facilities in order to stabilize the dislocation arrangement present in the stress-applied state.

Journal ArticleDOI
TL;DR: In this paper, the tensile strength of water under dynamic loading conditions in the absence of a free surface was investigated and the authors reported the results of an experimental study of water tensiles.
Abstract: This paper reports the results of an experimental study of the tensile strength of water under dynamic loading conditions in the absence of a free surface.

01 Sep 1969
TL;DR: In this article, the effect of the size of the disc on the tensile strength of a disc has been investigated and it has been found that the tensil strength decreases with the increase in the thickness of the disk and there is a marked effect of orientation of bedding planes on the calculated strength.
Abstract: The paper deals with disc test method for determining the tensile strength of rocks. The aim has been to study the effect of the size of the specimen on the strength of rocks and the effect of anisotropy on the tensile strength. It has been found that the tensile strength decreases with the increase in the thickness of the disc. There is a marked effect of orientation of bedding planes on the calculated strength of a disc. Tensile strength has been found to be highest when the applied load acts at 80° to the bedding planes. The least value was observed when the applied load was acting along the direction of the bedding planes.


Journal Article
TL;DR: The SPLIT CYLINDER test has been used to measure the strength of the ten-to-nine-force threshold of the Conqueror as discussed by the authors, and has been shown to be effective in detecting the failure of a Conqueror.
Abstract: THE SPLIT CYLINDER TEST, ASTM METHOD C 496, IS USED CURRENTLY TO SERVE AS A MEASURE OF THE TENSILE STRENGTH OF CONCRETE. AN ELASTIC FORMULA IS USED IN THIS METHOD TO DETERMINE THE CONCRETE STRENGTH BASED ON THE SPLITTING LOAD. HOWEVER, SINCE CONCRETE IS NONELASTIC, ESPECIALLY CLOSE TO THE FAILURE LOAD, A THEORETICAL AND EXPERIMENTAL INVESTIGATION OF THE MAGNITUDE AND DISTRIBUTION OF THE HORIZONTAL STRAINS ON THE FACE OF A SPLIT CYLINDER TEST HAS BEEN PERFORMED. IT WAS NECESSARY TO USE A STRAIN-REGULATED SCREW-TYPE TESTING MACHINE TO OBSERVE THE BEHAVIOR OF THE MATERIAL CLOSE TO ITS ULTIMATE FAILURE LOAD. ACCESSORY TESTS WERE PERFORMED TO DETERMINE THE MATERIAL STRESS-STRAIN CURVES AND POISSON'S RATIO FOR USE IN THE THEORETICAL STUDY. IT WAS FOUND THAT VERY LARGE NONELASTIC DEFORMATIONS OCCURRED BEFORE FINAL FAILURE BY SPLITTING, HORIZONTAL STRAIN OVER THE FACE HAD MAXIMUM VALUES AT ONE OR TWO POINTS, STRAINS WERE LARGEST AT THE VERTICAL DIAMETER AND RAPIDLY DECREASED TO EACH SIDE OF THAT DIAMETER, AND TRUE TENSILE STRENGTH APPEARED TO BE SMALLER THAN ELASTICALLY DETERMINED TENSILE STRENGTH. /AUTHOR/


Journal ArticleDOI
TL;DR: In this paper, the serrated flow, the Liiders bands and flow stress observed in Fe-23%Ni-0.24%C martensite during tensile test were studied at various temperatures between-196 and 220•Ž.
Abstract: Synopsis: The serrated flow, the Liiders bands and flow stress observed in Fe-23%Ni-0.24%C martensite during tensile test were studied at various temperatures between-196 and 220•Ž. The results obtained were as follows: (1) Temperature dependence of flow stress of the Fe-Ni-C martensite was explained in terms of the rearrangement of carbon atoms due to Snoek type or Cottrell type pinning, or of the clustering of carbon atoms or the precipitation of fine carbide particles on dislocations. The strain hardening at the early stage of deformation was remarkable in the martensite. ( 2 ) Serrated flow was found at a certain range of the test temperature. The temperature range varied with the strain rate. For example, the serration appeared between 1 and 170•Ž for the strain rate of 5'6•~ 10-4/ sec. At this temperature range, the increment in 0.2%-flow-stress was observed, but the strain hardening during serrated region was not so much. ( 3 ) The distinct Luders bands were observed during serrated flow. One Liiders band corresponded to one stress drop of the serration. The characteristic of Liiders bands in the martensite differed from that of annealed mild steel. The finer Liiders bands were uniformly distributed in the martensite, the larger total elongation was observed. ( 4 ) From the analysis of the critical condition for the serration, it was found that (a) a certain degree of plastic strain was necessary for the serrated flow to occur and (b) each step of yielding during serrated flow was an independent process of dynamic strain aging and was associated with the occurrence of one Liiders band. (Received Feb. 12, 1969)

01 Oct 1969
TL;DR: In this paper, the theory of the uniaxial tensile test of a brittle material is discussed, and the development and calibration of an apparatus designed to subject fine-grained polycrystalline ice specimens to UIT and compressive loads up to failure, and to give a continuous stress-strain curve during the loading cycle.
Abstract: : The report discusses the theory of the uniaxial tensile test of a brittle material and describes in detail the development and calibration of an apparatus designed to subject fine-grained polycrystalline ice specimens to uniaxial tensile and compressive loads up to failure, and to give a continuous stress-strain curve during the loading cycle. (Author)