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5.1 The round robin testing on which the precision and bias for this test method have been determined employed a range of graphites (see Table 2) whose grain sizes were of the order of 1 mil to 1/4 in. (0.0254 mm to 6.4 mm) and larger. This wide range of carbons and graphites can be tested with uniform gauge diameters with minimum parasitic stresses to provide quality data for use in engineering applications rather than simply for quality control. This test method can be easily adapted to elevated temperature testing of carbons and graphites without changing the specimen size or configuration by simply utilizing elevated temperature materials for the load train. This test method has been utilized for temperatures as high as 4352 °F (2400 °C). The design of the fixtures (Figs. 2-9 and Table 1) and description of the procedures are intended to bring about, on the average, parasitic stresses of less than 5 %. The specimens for the different graphites have been designed to ensure fracture within the gauge section commensurate with experienced variability in machining and testing care at different facilities. The constant gauge diameter permits rigorous analytical treatment. Note 1: Refer to Fig. 2, Items 101 and 115. Note 1: Refer to Fig. 2, Items 103 and 117. (A) Screw size. Note 1: Refer to Fig. 2, Items 107, 109, 111, 113, 121, 123, and 129. Note 1: Refer to Fig. 2, Items 105, 109, 113, 119, 123, 125, and 129. Note 1: Refer to Fig. 2, Items 108, 112, 122, and 128. FIG. 9 Attachment for Strain Flags or Extensometers to Provide Minimum Damage to Surface of Specimen Note 1: Jig align to ensure precision gauge length; mount post or groove to match type of extensometer. 5.2 Carbon and graphite materials exhibit significant physical property differences within parent materials. Exact sampling patterns and grain orientations must be specified in order to make meaningful tensile strength comparisons. See also Test Methods C565. 1.1 This test method covers the testing of carbon and graphite in tension to obtain the tensile stress-strain behavior, to failure, from which the ultimate strength, the strain to failure, and the elastic moduli may be calculated as may be required for engineering applications. Table 2 lists suggested sizes of specimens that can be used in the tests. Note 1: The results of about 400 tests, on file at ASTM as a research report, show the ranges of materials that have been tested, the ranges of specimen configurations, and the agreement between the testers. See Section 11. Note 2: For safety considerations, it is recommended that the chains be surrounded by suitable members so that at failure all parts of the load train behave predictably and do not constitute a hazard for the operator. 1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. Conversions are not provided in the tables and figures. 1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 Information concerning the thermal expansion characteristics of rocks is important in the design of underground excavation where the temperature of the surrounding rock may be altered. Depending on the restraint conditions, thermal strain may cause thermal stress that may affect the stability of underground excavations. Examples of applications where an understanding of rock thermal strain is important include: nuclear waste repositories, underground power stations, compressed air energy storage facilities, energy foundations, and geothermal energy facilities.5.2 The coefficient of linear thermal expansion, α, of rock is known to vary as the temperature changes. Rock thermal strain is normally not a linear function of temperature. This test method provides a procedure for continuously monitoring thermal strain as a function of temperature. Therefore, information on how the coefficient of linear thermal expansion changes with temperature is obtained.5.3 Other methods of measuring the coefficient of linear thermal expansion of rock by averaging the thermal strain of a large specimen over a temperature range of many degrees may result in failure to determine the variation in α of that rock for one or more of the following reasons:5.3.1 α is not always linear with temperature,5.3.2 Some rocks are anisotropic having directional characteristics which can vary by more than a factor of two. If anisotropy is expected, specimen with different orientations should be prepared and tested.5.3.3 α may have a negative value in one direction and, at the same time, a positive value in the others.5.4 Both wire and foil type strain gauges have been successfully employed to measure the thermal expansion coefficients of rock. These coefficients are frequently very small, being on the order of millionths of a millimetre per millimetre for each degree Celsius. The thermal strain of rocks is about one-tenth that of plastics and one-half or one-quarter that of many metals. Therefore, measurement methods for rocks require greater precision than methods that are routinely used on plastics and metals.NOTE 4: The quality of the results produced by this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/inspection/etc. Users of this standard are cautioned that compliance with Practice D3740 does not in itself ensure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This test method covers the laboratory determination of the linear (one-dimensional) coefficient of thermal expansion of rock using bonded electric resistance strain gauges. This test method is intended for evaluation of intact rock cores. Discontinuities in the rock mass, such as joints, inclusions, voids, veins, bedding, and the like can influence the thermal expansion of the rock, and judgment should be used when selecting the specimen to be analyzed in this test method.1.2 This test method is applicable for unconfined stress states over the temperature range from 20 to 260°C.NOTE 1: Unconfined tests performed at elevated temperatures may alter the mineralogy or grain structure of the test specimen. This alteration may change the physical and thermal properties of the test specimen.NOTE 2: The strain gauges are mounted with epoxy. Most commercially available high temperature epoxies require elevated temperature curing. The elevated temperature required for this curing may alter the physical and thermal properties of the test specimen. Epoxy should be selected based upon the maximum expected test temperature. Room temperature curing epoxy should be used whenever practical.1.3 The test specimens may be either saturated, dry or unsaturated. If saturated or unsaturated specimens are used, then the test temperature shall be at least 10°C less than the boiling point of the saturating fluid in order to reduce the effects of evaporation of the fluid.NOTE 3: When testing a saturated specimen, the gravimetric water content of the specimen may change unless special precautions are taken to encapsulate the test specimen. Refer to 7.4.1.4 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.5.1 The procedure used to specify how data are collected/recorded or calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any considerations for the user’s objectives; and it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analytical methods for engineering design.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory requirements prior to use.

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5.1 The thermal strain measurements allow for the calculation of the coefficient of axial thermal contraction, which can be directly used in the mechanistic-empirical pavement design methods.5.2 The thermal stress and strain measurements allow calculations of the modulus of asphalt mixture in the temperature domain.5.3 From modulus versus temperature and thermal stress versus temperature relationships the thermal viscoelastic and fracture properties are determined for asphalt mixtures.5.4 The derived modulus, thermal viscoelastic, and fracture properties may be used in evaluating the low-temperature cracking resistance of asphalt mixtures.NOTE 1: The quality of the results produced by this standard are dependent on the competence of the personnel performing the procedure and the capability, calibration, and maintenance of the equipment used. Agencies that meet the criteria of Specification D3666 are generally considered capable of competent and objective testing, sampling, inspection, etc. Users of this standard are cautioned that compliance with Specification D3666 alone does not completely ensure reliable results. Reliable results depend on many factors; following the suggestions of Specification D3666 or some similar acceptable guideline provides a means of evaluating and controlling some of those factors.1.1 This method of test is used to determine the thermal viscoelastic and thermal volumetric properties of field-cored or laboratory-compacted asphalt mixture specimens by measuring the thermally induced stress and strain while being cooled at a constant rate from an initial equilibrium temperature. The thermal stress and strain shall be measured using the uniaxial thermal stress and strain tester (UTSST).1.2 This standard test method covers procedures for preparing and testing asphalt mixtures to measure thermal stress and strain and directly calculate: (1) the coefficient of axial thermal contraction, and (2) the modulus of asphalt mixture over a range of temperatures.1.3 The procedure described in this standard provides required information for estimation of thermal cracking susceptibility of asphalt mixtures. The procedure applies to test specimens having a maximum aggregate size of 19 mm or less.1.4 This standard can be used for conventional and nonconventional asphalt mixtures including but not limited to: hot asphalt mixtures, asphalt mixture with recycled materials, cold asphalt mixtures, warm asphalt mixtures, and neat or modified asphalt mixtures (for example, polymer or rubber-modified).1.5 This standard can be used to determine the following:1.5.1 Thermal stress buildup in asphalt mixture during a single cooling event.1.5.2 Thermal strain in asphalt mixtures as a function of temperature.1.5.3 Coefficient of axial thermal contraction.1.5.4 Modulus of asphalt mixture as a function of temperature.1.5.5 Thermal viscoelastic properties of asphalt mixture: viscous softening, viscous-glassy transition, glassy hardening, crack initiation, fracture temperature, and fracture stress.1.5.6 UTSST cracking resistance index (CRI).1.5.7 UTSST CRI adjusted for environmental condition (CRIEnv).1.6 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.7 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.1.8 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.9 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM E1561-20 Standard Practice for Analysis of Strain Gage Rosette Data Active 发布日期 :  1970-01-01 实施日期 : 

This practice defines a reference axis for each of the two principal types of rosette configurations and the equations used for three-element strain gage rosette data analysis. The primary uses of this analysis procedure are to determine the directions and magnitudes of the principal surface strains, and to determine residual stresses. This is important for consistency in reporting results and for avoiding ambiguity in data analysis, especially when computers are used. There are several possible sets of equations, but the set presented herein is perhaps the most common.1.1 The two primary uses of three-element strain gage rosettes are (a) to determine the directions and magnitudes of the principal surface strains and (b) to determine residual stresses. Residual stresses are treated in a separate ASTM standard, Test Method E837. This practice defines a reference axis for each of the two principal types of rosette configurations used and presents equations for data analysis. This is important for consistency in reporting results and for avoiding ambiguity in data analysis—especially when computers are used. There are several possible sets of equations, but the set presented here is perhaps the most common.1.2 The equations in 4.2 and 4.3 of this practice are derived from infinitesimal (linear) strain theory. They are very accurate for the low strain levels normally encountered in the stress analysis of typical metal test objects. They become detectably inaccurate for strain levels greater than about 1 %. Rosette data reduction for larger strains is beyond the scope of this practice.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 The property KIc (GIc) determined by these test methods characterizes the resistance of a material to fracture in a neutral environment in the presence of a sharp crack under severe tensile constraint, such that the state of stress near the crack front approaches plane strain, and the crack-tip plastic (or non-linear viscoelastic) region is small compared with the crack size and specimen dimensions in the constraint direction. A KIc value is believed to represent a lower limiting value of fracture toughness. This value has been used to estimate the relation between failure stress and defect size for a material in service wherein the conditions of high constraint described above would be expected. Background information concerning the basis for development of these test methods in terms of linear elastic fracture mechanics can be found in Refs (1-5).35.1.1 The KIc (GIc) value of a given material is a function of testing speed and temperature. Furthermore, cyclic loads have been found to cause crack extension at K values less than KIc (GIc). Crack extension under cyclic or sustained load will be increased by the presence of an aggressive environment. Therefore, application of KIc (GIc) in the design of service components should be made considering differences that may exist between laboratory tests and field conditions.5.1.2 Plane-strain fracture toughness testing is unusual in that sometimes there is no advance assurance that a valid KIc (GIc) will be determined in a particular test. Therefore it is essential that all of the criteria concerning validity of results be carefully considered as described herein.5.1.3 Clearly, it will not be possible to determine KIc (GIc) if any dimension of the available stock of a material is insufficient to provide a specimen of the required size.5.2 Inasmuch as the fracture toughness of plastics is often dependent on specimen process history, that is, injection molded, extruded, compression molded, etc., the specimen crack orientation (parallel or perpendicular) relative to any processing direction shall be noted on the report form discussed in 10.1.5.3 Before proceeding with this test method, reference should be made to the specification of the material being tested. Any test specimen preparation, conditioning, dimensions, or testing parameters, or combination thereof, covered in the relevant ASTM materials specification shall take precedence over those mentioned in this test method. If there are no relevant ASTM material specifications, then the default conditions apply.1.1 These test methods are designed to characterize the toughness of plastics in terms of the critical-stress-intensity factor, KIc, and the energy per unit area of crack surface or critical strain energy release rate, GIc, at fracture initiation.1.2 Two testing geometries are covered by these test methods, single-edge-notch bending (SENB) and compact tension (CT).1.3 The scheme used assumes linear elastic behavior of the cracked specimen, so certain restrictions on linearity of the load-displacement diagram are imposed.1.4 A state-of-plane strain at the crack tip is required. Specimen thickness must be sufficient to ensure this stress state.1.5 The crack must be sufficiently sharp to ensure that a minimum value of toughness is obtained.1.6 The significance of these test methods and many conditions of testing are identical to those of Test Method E399, and, therefore, in most cases, appear here with many similarities to the metals standard. However, certain conditions and specifications not covered in Test Method E399, but important for plastics, are included.1.7 This protocol covers the determination of GIc as well, which is of particular importance for plastics.1.8 These test methods give general information concerning the requirements for KIc and GIc testing. As with Test Method E399, two annexes are provided which give the specific requirements for testing of the SENB and CT geometries.1.9 Test data obtained by these test methods are relevant and appropriate for use in engineering design.1.10 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.NOTE 1: This standard and ISO 13586 address the same subject matter, but differ in technical content.1.11 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 This guide is intended to describe heat management program elements that foundries use to prevent or manage heat strain and heat-related illness. Specifically, the guide:4.1.1 Provides an objective framework for recognizing heat stress and heat strain, and4.1.2 Facilitates use of best practices to manage heat exposures to minimize heat strain and prevent heat-related illness.1.1 This guide is intended to establish best practices for recognizing and managing occupational heat stress and heat strain in foundry environments.1.2 Objectives of the foundry heat stress and heat strain management guide are as follows:1.2.1 Provide an objective framework for recognizing heat stress and heat strain, and1.2.2 Facilitate use of best practices to manage heat exposures to minimize heat strain and prevent heat-related illness.1.3 In this guide, procedures necessary to manage heat stress and heat strain in foundries are described.1.4 Key elements of this guide include definitions of heat stress and heat strain, plus techniques for recognizing, communicating, managing, and controlling heat stress and heat strain to prevent heat-related illnesses.1.5 Units—The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 Low strain impact integrity testing provides acceleration or velocity and force (optional) data on slender structural elements (that is, structural columns, driven concrete piles, cast in place concrete piles, concrete filled steel pipe piles, timber piles, etc.). The method works best on solid concrete sections, and has limited application to unfilled steel pipe piles, H piles, or steel sheet piles. These data assist evaluation of the pile cross-sectional area and length, the pile integrity and continuity, as well as consistency of the pile material, although evaluation is approximate. This test method will not provide information regarding the pile bearing capacity. It is generally helpful to consider the soil profile, construction method and site records when evaluating data obtained by this method. Other useful information to consider and compare with results of this test includes low strain integrity test results of similar piles at the same site, concrete cylinder or core strength test results, automated monitoring data on equipment placing the concrete when augered piles are used, or information obtained from crosshole sonic logging (Test Method D6760) or thermal integrity profiling (Test Methods D7949) if available.4.1.1 Methods of Testing: 4.1.1.1 Pulse Echo Method (PEM)—The pile head motion is measured as a function of time. The time domain record is then evaluated for pile integrity.4.1.1.2 Transient Response Method (TRM)—The pile head motion and force (measured with an instrumented hammer) are measured as a function of time. The data are evaluated usually in the frequency domain.1.1 This test method covers the procedure for determining the integrity of individual vertical or inclined piles by measuring and analyzing the velocity (required) and force (optional) response of the pile induced by an (hand held hammer or other similar type) impact device usually applied axially and perpendicularly to the pile head surface. This test method is applicable to long structural elements that function in a manner similar to any deep foundation units (such as driven piles, augeured piles, or drilled shafts), regardless of their method of installation provided that they are receptive to low strain impact testing.1.2 This standard provides minimum requirements for low strain impact testing of piles. Plans, specifications, and/or provisions prepared by a qualified engineer, and approved by the agency requiring the test(s), may provide additional requirements and procedures as needed to satisfy the objectives of a particular test program.1.3 The text of this standard references notes and footnotes which provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026.1.6 The method used to specify how data are collected, calculated, or recorded in this standard is not directly related to the accuracy to which the data can be applied in design or other uses, or both. How one applies the results obtained using this standard is beyond its scope.1.7 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.NOTE 1: he quality of the result produced by this test method is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities used. Agencies that meet the criteria of Practice D3740 are generally considered capable of competent and objective testing/sampling/ inspection/etc. Users of this test method are cautioned that compliance with Practice D3740 does not in itself assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.

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5.1 The fracture toughness determined by this test method characterizes the resistance of a material to fracture by a slowly advancing steady-state crack (see 3.2.5) in a neutral environment under severe tensile constraint. The state of stress near the crack front approaches plane strain, and the crack-tip plastic region is small compared with the crack size and specimen dimensions in the constraint direction. A KIv or KIvj value may be used to estimate the relation between failure stress and defect size when the conditions described above would be expected, although the relationship may differ from that obtained from a KIc value (see Note 1). Background information concerning the basis for development of this test method in terms of linear elastic fracture mechanics may be found in Refs (6-15). 5.1.1 The KIv, KIvj, or KIvM value of a given material can be a function of testing speed (strain rate) and temperature. Furthermore, cyclic forces can cause crack extension at KI values less than KIv, and crack extension can be increased by the presence of an aggressive environment. Therefore, application of KIv in the design of service components should be made with an awareness of differences that may exist between the laboratory tests and field conditions. 5.1.2 Plane-strain fracture toughness testing is unusual in that there can be no advance assurance that a valid KIv, KIvj, or KIvM will be determined in a particular test. Therefore, it is essential that all the criteria concerning the validity of results be carefully considered as described herein. 5.2 This test method can serve the following purposes: 5.2.1 To establish the effects of metallurgical variables such as composition or heat treatment, or of fabricating operations such as welding or forming, on the fracture toughness of new or existing materials. 5.2.2 For specifications of acceptance and manufacturing quality control, but only when there is a sound basis for specification of minimum KIv, KIvj, or KIvM values, and then only if the dimensions of the product are sufficient to provide specimens of the size required for valid KIv determination (9). The specification of KIv values in relation to a particular application should signify that a fracture control study has been conducted on the component in relation to the expected history of loading and environment, and in relation to the sensitivity and reliability of the crack detection procedures that are to be applied prior to service and subsequently during the anticipated life. 5.2.3 To provide high spatial resolution in measuring plane strain fracture toughness variations in parent pieces of material (14). Note 2: The high spatial resolution is possible because of the small allowable specimen size criterion, B ≥ 1.25 (KIv /σYS)2 (9), and because the toughness is measured at approximately the midline of the specimen, and only in the material covered by the crack's lateral extent, which is about one third of the specimen's lateral dimension, B. 1.1 This test method covers the determination of plane-strain (chevron-notch) fracture toughnesses, KIv or KIvM, of metallic materials. Fracture toughness by this method is relative to a slowly advancing steady state crack initiated at a chevron-shaped notch, and propagating in a chevron-shaped ligament (Fig. 1). Some metallic materials, when tested by this method, exhibit a sporadic crack growth in which the crack front remains nearly stationary until a critical load is reached. The crack then becomes unstable and suddenly advances at high speed to the next arrest point. For these materials, this test method covers the determination of the plane-strain fracture toughness, KIvj or KIvM, relative to the crack at the points of instability. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 Strain-controlled fatigue is a phenomenon that is influenced by the same variables that influence force-controlled fatigue. The nature of strain-controlled fatigue imposes distinctive requirements on fatigue testing methods. In particular, cyclic total strain should be measured and cyclic plastic strain should be determined. Furthermore, either of these strains typically is used to establish cyclic limits; total strain usually is controlled throughout the cycle. The uniqueness of this test method and the results it yields are the determination of cyclic stresses and strains at any time during the tests. Differences in strain histories other than constant-amplitude alter fatigue life as compared with the constant amplitude results (for example, periodic overstrains and block or spectrum histories). Likewise, the presence of nonzero mean strains and varying environmental conditions may alter fatigue life as compared with the constant-amplitude, fully reversed fatigue tests. Care must be exercised in analyzing and interpreting data for such cases. In the case of variable amplitude or spectrum strain histories, cycle counting can be performed with Practice E1049.4.2 Strain-controlled fatigue can be an important consideration in the design of industrial products. It is important for situations in which components or portions of components undergo either mechanically or thermally induced cyclic plastic strains that cause failure within relatively few (that is, approximately <105) cycles. Information obtained from strain-controlled fatigue testing may be an important element in the establishment of design criteria to protect against component failure by fatigue.4.3 Strain-controlled fatigue test results are useful in the areas of mechanical design as well as materials research and development, process and quality control, product performance, and failure analysis. Results of a strain-controlled fatigue test program may be used in the formulation of empirical relationships between the cyclic variables of stress, total strain, plastic strain, and fatigue life. They are commonly used in data correlations such as curves of cyclic stress or strain versus life and cyclic stress versus cyclic plastic strain obtained from hysteresis loops at some fraction (often half) of material life. Examination of the cyclic stress–strain curve and its comparison with monotonic stress–strain curves gives useful information regarding the cyclic stability of a material, for example, whether the values of hardness, yield strength, ultimate strength, strain-hardening exponent, and strength coefficient will increase, decrease, or remain unchanged (that is, whether a material will harden, soften, or be stable) because of cyclic plastic straining (1).3 The presence of time-dependent inelastic strains during elevated temperature testing provides the opportunity to study the effects of these strains on fatigue life and on the cyclic stress-strain response of the material. Information about strain rate effects, relaxation behavior, and creep also may be available from these tests. Results of the uniaxial tests on specimens of simple geometry can be applied to the design of components with notches or other complex shapes, provided that the strains can be determined and multiaxial states of stress or strain and their gradients are correctly correlated with the uniaxial strain data.1.1 This test method covers the determination of fatigue properties of nominally homogeneous materials by the use of test specimens subjected to uniaxial forces. It is intended as a guide for fatigue testing performed in support of such activities as materials research and development, mechanical design, process and quality control, product performance, and failure analysis. While this test method is intended primarily for strain-controlled fatigue testing, some sections may provide useful information for force-controlled or stress-controlled testing.1.2 The use of this test method is limited to specimens and does not cover testing of full-scale components, structures, or consumer products.1.3 This test method is applicable to temperatures and strain rates for which the magnitudes of time-dependent inelastic strains are on the same order or less than the magnitudes of time-independent inelastic strains. No restrictions are placed on environmental factors such as temperature, pressure, humidity, medium, and others, provided they are controlled throughout the test, do not cause loss of or change in dimension with time, and are detailed in the data report.NOTE 1: The term inelastic is used herein to refer to all nonelastic strains. The term plastic is used herein to refer only to the time-independent (that is, noncreep) component of inelastic strain. To truly determine a time-independent strain the force would have to be applied instantaneously, which is not possible. A useful engineering estimate of time-independent strain can be obtained when the strain rate exceeds some value. For example, a strain rate of 1 × 10−3 sec−1 is often used for this purpose. This value should increase with increasing test temperature.1.4 This test method is restricted to the testing of uniform gage section test specimens subjected to axial forces as shown in Fig. 1(a). Testing is limited to strain-controlled cycling. The test method may be applied to hourglass specimens, see Fig. 1(b), but the user is cautioned about uncertainties in data analysis and interpretation. Testing is done primarily under constant amplitude cycling and may contain interspersed hold times at repeated intervals. The test method may be adapted to guide testing for more general cases where strain or temperature may vary according to application specific histories. Data analysis may not follow this test method in such cases.FIG. 1 Recommended Low-Cycle Fatigue SpecimensNOTE 1: * Dimension d is recommended to be 6.35 mm [0.25 in.]. See 7.1. Centers permissible. ** This diameter may be made greater or less than 2d depending on material hardness. In typically ductile materials diameters less than 2d are often employed and in typically brittle materials diameters greater than 2d may be found desirable.NOTE 2: Threaded connections are more prone to inferior axial alignment and have greater potential for backlash, particularly if the connection with the grip is not properly designed.1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 This test method is useful for estimating the strain at the onset of necking in a uniaxial tension test (1). Practically, it provides an empirical parameter for appraising the relative stretch formability of similar metallic systems. The strain-hardening exponent is also a measure of the increase in strength of a material due to plastic deformation.5.2 The strain-hardening exponent may be determined over the entire plastic stress-strain curve or any portion(s) of the stress-strain curve specified in a product specification.NOTE 4: The engineering strain interval 10–20% is commonly used for determining the strain-hardening exponent, n, of formable low-carbon steel products5.3 This test method is not intended to apply to any portion of the true stress versus true strain curve that exhibits discontinuous behavior; however, the method may be applied by curve-smoothing techniques as agreed upon.NOTE 5: For example, those portions of the stress-strain curves for mild steel, aluminum, or other alloys that exhibit yield point and Lüders band elongation, twinning, or Portevin–Le Chatelier effect (PLC) may be characterized as behaving discontinuously.NOTE 6: Caution should be observed in the use of curve-smoothing techniques as they may affect the n-value.5.4 This test method is suitable for determining the tensile stress-strain response of metallic sheet materials in the plastic region prior to the onset of necking.5.5 The n-value may vary with the displacement rate or strain rate used, depending on the metal and test temperature.1.1 This test method covers the determination of a strain-hardening exponent by tension testing of metallic sheet materials for which plastic-flow behavior obeys the power curve given in the Introduction.NOTE 1: A single power curve may not be a satisfactory fit to the entire stress-strain curve between yield and necking. If such is the case, more than one value of the strain-hardening exponent may be obtained (2) by agreement using this test method.1.2 This test method is specifically for metallic sheet materials with thicknesses of at least 0.005 in. (0.13 mm) but not greater than 0.25 in. (6.4 mm). The method has successfully been and may be applied to other forms and thicknesses by agreement1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.NOTE 2: The value of the strain-hardening exponent, n, has no units and is independent of the units used in its determination1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

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ASTM E1319-23 Standard Guide for High-Temperature Static Strain Measurement Active 发布日期 :  1970-01-01 实施日期 : 

4.1 The use of this guide is voluntary and is intended for use as a procedures guide for selection and application of specific types of strain gages for high-temperature installations. No attempt is made to restrict the type of strain gage types or concepts to be chosen by the user. The provisions of this guide may be invoked in specifications and procedures by specifying those that shall be considered mandatory for the purpose of the specific application. When so invoked, the user shall include in the work statement a notation that provisions of this guide shown as recommendation shall be considered mandatory for the purposes of the specification or procedure concerned, and shall include a statement of any exceptions to or modifications of the affected provisions of this guide.1.1 This guide covers the selection and application of strain gages for the measurement of static strain up to and including the temperature range from 425 °C to 650 °C (800 °F to 1200 °F). This guide reflects some state-of-the-art techniques in high-temperature strain measurement.1.2 This guide assumes that the user is familiar with the use of bonded strain gages and associated signal conditioning circuits and instrumentation as discussed in (1) and (2).2 The strain gage systems described are those that have proven effective in the temperature range of interest and were available at the time of issue of this guide. It is not the intent of this guide to limit the user to one of the strain gage types described nor is it the intent to specify the type of strain gage system to be used for a specific application. However, in using any strain gage system including those described, the proposer shall be able to demonstrate the capability of the proposed strain gage system to meet the selection criteria provided in Section 5 and the needs of the specific application.1.3 The devices and techniques described in this guide can sometimes be applicable at temperatures above and below the range noted, and for making dynamic strain measurements at high temperatures with proper precautions. The strain gage manufacturer should be consulted for recommendations and details of such applications.1.4 The references are a part of this guide to the extent specified in the text.1.5 The values stated in metric (SI) units are to be regarded as the standard. The values given in parentheses are for informational purposes only.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 This test method determines the long-term ring-bending strain of pipe when deflected under constant load and immersed in a chemical environment. It has been found that effects of chemical environments can be accelerated by strain induced by deflection. This information is useful and necessary for the design and application of buried fiberglass pipe.NOTE 3: Pipe of the same diameter but of different wall thicknesses will develop different strains with the same deflection. Also, pipes having the same wall thickness but different constructions making up the wall may develop different strains with the same deflection.1.1 This test method covers a procedure for determining the long-term ring-bending strain (Sb) of “fiberglass” pipe. Both glass-fiber-reinforced thermosetting-resin pipe (RTRP) and glass-fiber-reinforced polymer mortar pipe (RPMP) are “fiberglass” pipes.1.2 The values stated in inch-pound units are to be regarded as the standard. The SI units given in parentheses are for information only.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. A specific warning statement is given in 9.5.NOTE 1: There is no known ISO equivalent to this standard.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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4.1 Creep tests measure the time-dependent deformation under force at a given temperature, and, by implication, the force-carrying capability of the material for limited deformations. Creep rupture tests, properly interpreted, provide a measure of the force-carrying capability of the material as a function of time and temperature. The two tests complement each other in defining the force-carrying capability of a material for a given period of time. In selecting materials and designing parts for service at elevated temperatures, the type of test data used will depend on the criteria for force-carrying capability that best defines the service usefulness of the material.4.2 This test method may be used for material development, quality assurance, characterization, and design data generation.4.3 High-strength, monolithic ceramic materials, generally characterized by small grain sizes (<50 μm) and bulk densities near their theoretical density, are candidates for load-bearing structural applications at elevated temperatures. These applications involve components such as turbine blades which are subjected to stress gradients and multiaxial stresses.4.4 Data obtained for design and predictive purposes shall be obtained using any appropriate combination of test methods that provide the most relevant information for the applications being considered. It is noted here that ceramic materials tend to creep more rapidly in tension than in compression (1-3).4 This difference results in time-dependent changes in the stress distribution and the position of the neutral axis when tests are conducted in flexure. As a consequence, deconvolution of flexural creep data to obtain the constitutive equations needed for design cannot be achieved without some degree of uncertainty concerning the form of the creep equations, and the magnitude of the creep rate in tension vis-a-vis the creep rate in compression. Therefore, creep data for design and life prediction shall be obtained in both tension and compression, as well as the expected service stress state.1.1 This test method covers the determination of tensile creep strain, creep strain rate, and creep time to failure for advanced monolithic ceramics at elevated temperatures, typically between 1073 and 2073 K. A variety of test specimen geometries are included. The creep strain at a fixed temperature is evaluated from direct measurements of the gage length extension over the time of the test. The minimum creep strain rate, which may be invariant with time, is evaluated as a function of temperature and applied stress. Creep time to failure is also included in this test method.1.2 This test method is for use with advanced ceramics that behave as macroscopically isotropic, homogeneous, continuous materials. While this test method is intended for use on monolithic ceramics, whisker- or particle-reinforced composite ceramics as well as low-volume-fraction discontinuous fiber-reinforced composite ceramics may also meet these macroscopic behavior assumptions. Continuous fiber-reinforced ceramic composites (CFCCs) do not behave as macroscopically isotropic, homogeneous, continuous materials, and application of this test method to these materials is not recommended.1.3 The values in SI units are to be regarded as the standard (see IEEE/ASTM SI 10). The values given in parentheses are mathematical conversions to inch-pound units that are provided for information only and are not considered standard.1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 This test method is based on the Payne Effect. It is a reasonable approach to evaluate the compound’s filler-network formation to quantify the degree of silanization in a silica-filled rubber using a rotorless oscillating shear rheometer for the measurement of the strain softening.5.2 This test is based on silane’s capability to suppress silica filler network formation (flocculation) and correlates this behavior to the resultant degree of silanization.5.3 The optimal mixing conditions can be selected based on the silanization/property correlations to give desired compound properties. The degree of silanization quantified by this test method is used for controlling and predicting compound properties regardless of the mixing scheme or equipment, or both.1.1 This test method is used to rheologically determine the degree of silanization in a silica filled compound. Silanization is the chemical reaction related to covering the silica surface with organosilanes for a better incorporation of silica into rubber. Bifunctional silanes can provide coupling between silica and rubber for enhanced rubber reinforcement.1.2 Units—The values stated in SI units are to be regarded as the standard. No other units of measurement are included in this standard.1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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5.1 This test method is used to measure viscoelastic properties through the strain softening effects of a strain amplitude sweep (the Payne Effect).5.2 For the uncured state, the time conditioning and strain amplitude strain sweeps can relate to colloidal silica particle or carbon black deagglomeration from the mixing process. The profile of this Payne Effect from G’ storage modulus can also be a function of loading levels and particle size of these fillers in the rubber hydrocarbon medium. In addition, with silica and an organosilane additive, this G’ strain softening effect can determine if a given silanization reaction between a subject silica and an organosilane was achieved through reactive mixing. If the silanization reaction during the mixing was not achieved, the maximum G’ storage modulus from the strain sweep will not be lowered and the silica particle attraction to other silica particles will still be high resulting in a more dense filler network that remains.1.1 This test method covers the use of a sealed cavity rotorless oscillating shear rheometer for the measurement of the softening effects of rising sinusoidal strain when applied to an unvulcanized rubber compound containing significant amounts of colloidal fillers (such as silica or carbon black, or both) from a rubber mixing procedure. These strain softening properties relate to mixing conditions, the composition of the rubber compound, colloidal particle (Payne Effect) characteristics of the fillers, and in some cases the degree of reaction between an organosilane and precipitated, hydrated silica during mixing. This procedure is being commonly applied to rubber reactive mixing procedures.1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.1.3 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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