定价： 468元 / 折扣价： 398 元 加购物车

定价： 689元 / 折扣价： 586 元

定价： 260元 / 折扣价： 221 元 加购物车

定价： 260元 / 折扣价： 221 元 加购物车

5.1 This practice for plane-strain fracture toughness testing of aluminum alloys may be used as a supplement to Test Method E399. The application of this practice is primarily intended for quality assurance and material release in cases where valid plane-strain fracture toughness data cannot be obtained per Test Method E399.5.2 It must be understood that the interpretations and guidelines in this practice do not alter the validity requirements of Test Method E399 or promote the designation of data that are invalid according to Test Method E399 to a “valid” condition. This practice is primarily concerned with cases where it is not possible or practical to obtain valid data, but where material release judgments must be made against specified fracture toughness values. Where it is possible to obtain a valid plane-strain fracture toughness value by replacement testing according to Test Method E399, that is the preferred approach.1.1 This practice is applicable to the fracture toughness testing of all aluminum alloys, tempers, and products, especially in cases where the tests are being made to establish whether or not individual lots meet the requirements of specifications and should be released to customers.1.2 Test Method E399 is the basic test method to be used for plane-strain fracture toughness testing of aluminum alloys. The purpose of this practice is to provide supplementary information for plane-strain fracture toughness of aluminum alloys in three main areas:1.2.1 Specimen sampling,1.2.2 Specimen size selection, and1.2.3 Interpretation of invalid test results.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3.1 Exception—Certain inch-pound values given in parentheses are provided for information only.1.4 This standard is currently written to accommodate only C(T) specimens.1.5 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.1.6 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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Autogenous strain is the self-created bulk strain of cement paste, mortar, or concrete during hardening at constant temperature. In conventional concrete, autogenous shrinkage strain is generally negligible, but in concrete with low water-cementitious materials ratio (w/cm) or with silica fume it may be considerable (1).5 Restraint of the autogenous strain by aggregates or adjoining structural members may result in formation of micro and macro cracks that impair strength, durability and aesthetics. Cracks may also be a problem with regard to hygienic cleaning of surfaces.5.2 An accurate measurement of the autogenous strain of cementitious mixtures with low w/cm is important for evaluating the risk of early-age cracking of concrete structures. Measurements of autogenous strain have been carried out using either volumetric or linear methods. Both methods may show evidence of significant artifacts (1); therefore, results of the two methods may disagree considerably if not carried out properly.5.3 A sealed, flexible corrugated mold system (2) combines the advantages of linear and volumetric measurement of autogenous strain, while avoiding most of their disadvantages. The mold effectively prevents moisture loss and minimizes restraint to volume change during hardening. Moreover, results obtained with the corrugated mold system agree with those from the volumetric method, once some artifacts, in particular water absorption through the membrane used to contain the test specimen, have been eliminated in the latter (3,4). The corrugated mold system is easier to use and shows better repeatability than the volumetric technique (3,4). Measurements with the corrugated mold system are in good agreement with unrestrained length change measurements obtained using Test Method C157/C157M with sealed specimens (5); however, Test Method C157/C157M does not allow measurement of the shrinkage occurring before 24 h (5).5.4 This test method can be used to evaluate the effects of cementitious materials, admixtures, and mixture proportions on autogenous shrinkage strain of paste or mortar specimens.5.5 The autogenous shrinkage strain of mortar specimens will be less than that of paste specimens for the same w/cm. The autogenous shrinkage strain of concrete will be less than that of mortar for the same w/cm. The nominal maximum aggregate size for mortar used in this test method is 4.75 mm.1.1 This test method measures the bulk strain of a sealed cement paste or mortar specimen, including those containing admixtures, various supplementary cementitious materials (SCM), and other fine materials, at constant temperature and not subjected to external forces, from the time of final setting until a specified age. This strain is known as autogenous strain. Autogenous strain is most significant in concrete with low water-cementitious materials ratio (w/cm) (See Note 1).NOTE 1: A low water-cementitious materials ratio (w/cm) can be considered to be a water to cement ratio of 0.40 or lower for this test.1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of this 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. (Warning—Fresh hydraulic cementitious mixtures are caustic and may cause chemical burns to skin and tissue upon prolonged exposure.2)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.

定价： 590元 / 折扣价： 502 元 加购物车

4.1 This practice is designed to aid those interested in the engineering properties of roofing membranes.4.2 The data obtained will not permit prediction of the service life of a membrane under field conditions. The data will provide a basis for study of the mechanical properties of the membrane. Note that if strain rates, specimen dimensions, initial clear distance between clamps, or temperatures and moisture contents are varied, the data may not be strictly comparable.1.1 This practice is a guide for determining the load-strain properties of roofing membranes and their components at various temperatures. Test specimens may be prepared in the laboratory or cut from samples obtained in the field.1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.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.

定价： 515元 / 折扣价： 438 元 加购物车

4.1 The property KIc, determined by Test Method E399 or ISO 12135, characterizes a material's resistance to fracture in a neutral environment and in the presence of a sharp crack subjected to an applied opening force or moment within a field of high constraint to lateral plastic flow (plane strain condition). A KIc value is considered to be a lower limiting value of fracture toughness associated with the plane strain state.4.1.1 Thermal quenching processes used with precipitation hardened aluminum alloy products can introduce significant residual stresses.5 Mechanical stress relief procedures (stretching, compression) are commonly used to relieve these residual stresses in products with simple shapes. However, in the case of mill products with thick cross-sections (for example, heavy gauge plate or large hand forgings) or complex shapes (for example, closed die forgings, complex open die forgings, stepped extrusions, castings), complete mechanical stress relief is not always possible. In other instances residual stresses may be introduced into a product during fabrication operations such as straightening, forming, or welding operations.NOTE 1: For the purposes of this guide, only bulk residual stress is considered (that is, of the type typically created during a quench process for thermal heat treatment) and not engineered residual stress, such as from shot peening or cold hole expansion.4.1.2 Specimens taken from such products that contain residual stress will likewise themselves contain residual stress. While the act of specimen extraction in itself partially relieves and redistributes the pattern of original stress, the remaining magnitude can still be appreciable enough to cause significant error in the test result.4.1.3 Residual stress is a non-proportional internal stress that is superimposed on the applied stress and results in an actual crack-tip stress-intensity factor that is different from one based solely on externally applied forces or displacements, and residual stress can bias the toughness measurement. Conceptually, compressive residual stress in the region of the crack tip must be overcome by the applied force before the crack tip experiences tensile stresses, thus biasing the KQ or KIc measurement to a higher value, potentially producing a non-lower-bound toughness value. Quantitatively, the effect depends on stress equilibrium for the continuously varying residual stress field and the associated crack tip response. Conversely, a tensile residual stress is additive to the applied force and biases the measured KQ or Kic result to a lower value, potentially under-representing the material “true” toughness capability.4.1.4 Tests that utilize deep edge-notched specimens such as the compact tension C(T) are particularly sensitive to distortion during specimen machining when substantial residual stress is present. In general, for those cases where such residual stresses are thermal quench induced, the resulting KIc or KQ result is typically biased upward (that is, KQ is higher than that which would have been achieved in a residual stress-free specimen). The inflated values result from the redistribution of residual stress during specimen machining and excessive fatigue precrack front curvature caused by variable residual stresses across the crack front.64.2 This guide can serve the following purposes:4.2.1 Provide warning signs that the measured value of KIc has been biased by residual stresses and may not be a lower limit value of fracture toughness.4.2.2 Provide experimental methods that can be used to minimize the effect of residual stress on measured fracture toughness values.4.2.3 Suggest methods that can be used to correct residual stress influenced values of fracture toughness to values that approximate a fracture toughness value representative of a test performed without residual stress bias.1.1 This guide covers supplementary guidelines for plane-strain fracture toughness testing of aluminum products for which complete stress relief is not practicable. Guidelines for recognizing when residual stresses may be significantly biasing test results are presented, as well as methods for minimizing the effects of residual stress during testing. This guide also provides guidelines for an empirical correction as well as interpretation of data produced during the testing of these products. Test Method E399 is the standard test method to be used for plane-strain fracture toughness testing of aluminum alloys.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.

定价： 515元 / 折扣价： 438 元 加购物车

5.1 To model the mechanical characteristics of overhead electrical conductor, stress-strain characteristics must be determined. The most accurate method for determination of these characteristics is a laboratory stress-strain test. These mechanical characteristics can then be used to determine the strain response of a conductor to mechanical loads, and thus predict the sag of the conductor. This can then be used to determine the required installation parameters to provide safe clearance and tension for the conductor usage.1.1 This test method covers the measurement of the elastic and short-term creep characteristics of conductors for overhead power lines.1.2 Stress-strain data from tests performed in accordance with IEC 61089 are compliant with this standard.1.3 Stress-strain data from prior Aluminum Association testing procedures are compliant with this standard.1.4 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.1.5 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.1.6 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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 The slow strain rate test is used for relatively rapid screening or comparative evaluation, or both, of environmental, processing or metallurgical variables, or both, that can affect the resistance of a material to EAC. For example, this testing technique has been used to evaluate materials, heat treatments, chemical constituents in the environment, and temperature and chemical inhibitors.5.2 Where possible, the application of the SSR test and data derived from its use should be used in combination with service experience or long-term EAC data, or both, obtained through literature sources or additional testing using other testing techniques. In applications where there has been little or no prior experience with SSR testing or little EAC data on the particular material/environment combination of interest, the following steps are recommended:5.2.1 The SSR tests should be conducted over a range of applied extension rates (that is, usually at least one order of magnitude in applied extension rate above and below 10−6 in./s (2.54 × 10–5 mm/s) to determine the effect of strain rate or rate of increase of the stress or stress intensity factor on susceptibility to EAC.5.2.2 Constant load or strain EAC tests should also be conducted in simulated service environments, and service experience should be obtained so that a correlation between SSR test results and anticipated service performance can be developed.5.3 In many cases the SSR test has been found to be a conservative test for EAC. Therefore, it may produce failures in the laboratory under conditions which do not necessarily cause EAC under service application. Additionally, in some limited cases, EAC indications are not found in smooth tension SSR tests even when service failures have been observed. This effect usually occurs when there is a delay in the initiation of localized corrosion processes. Therefore, the suggestions given in 5.2 are strongly encouraged.5.4 In some cases, EAC will only occur in a specific range of strain rates. Therefore, where there is little prior information available, tests should be conducted over a range of strain rates as discussed in 5.2.1.1 This practice covers procedures for the design, preparation, and use of axially loaded, tension test specimens and fatigue pre-cracked (fracture mechanics) specimens for use in slow strain rate (SSR) tests to investigate the resistance of metallic materials to environmentally assisted cracking (EAC). While some investigators utilize SSR test techniques in combination with cyclic or fatigue loading, no attempt has been made to incorporate such techniques into this practice.1.2 Slow strain rate testing is applicable to the evaluation of a wide variety of metallic materials in test environments which simulate aqueous, nonaqueous, and gaseous service environments over a wide range of temperatures and pressures that may cause EAC of susceptible materials.1.3 The primary use of this practice is to furnish accepted procedures for the accelerated testing of the resistance of metallic materials to EAC under various environmental conditions. In many cases, the initiation of EAC is accelerated through the application of a dynamic strain in the gauge section or at a notch tip or crack tip, or both, of a specimen. Due to the accelerated nature of this test, the results are not intended to necessarily represent service performance, but rather to provide a basis for screening, for detection of an environmental interaction with a material, and for comparative evaluation of the effects of metallurgical and environmental variables on sensitivity to known environmental cracking problems.1.4 Further information on SSR test methods is available in ISO 7539 and in the references provided with this practice (1-6).21.5 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.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. Furthermore, in some cases, special facilities will be required to isolate these tests from laboratory personnel if high pressures or toxic chemical environments, or both, are utilized in SSR testing.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.

定价： 702元 / 折扣价： 597 元 加购物车

5.1 In structures containing gradients in either toughness or stress, a crack may initiate in a region of either low toughness or high stress, or both, and arrest in another region of either higher toughness or lower stress, or both. The value of the stress intensity factor during the short time interval in which a fast-running crack arrests is a measure of the ability of the material to arrest such a crack. Values of the stress intensity factor of this kind, which are determined using dynamic methods of analysis, provide a value for the crack-arrest fracture toughness which will be termed KA in this discussion. Static methods of analysis, which are much less complex, can often be used to determine K at a short time (1 to 2 ms) after crack arrest. The estimate of the crack-arrest fracture toughness obtained in this fashion is termed K a. When macroscopic dynamic effects are relatively small, the difference between KA and Ka is also small (1-4). For cracks propagating under conditions of crack-front plane-strain, in situations where the dynamic effects are also known to be small, KIa determinations using laboratory-sized specimens have been used successfully to estimate whether, and at what point, a crack will arrest in a structure (5, 6). Depending upon component design, loading compliance, and the crack jump length, a dynamic analysis of a fast-running crack propagation event may be necessary in order to predict whether crack arrest will occur and the arrest position. In such cases, values of K Ia determined by this test method can be used to identify those values of K below which the crack speed is zero. More details on the use of dynamic analyses can be found in Ref (4). 5.2 This test method can serve at least the following additional purposes: 5.2.1 In materials research and development, to establish in quantitative terms significant to service performance, the effects of metallurgical variables (such as composition or heat treatment) or fabrication operations (such as welding or forming) on the ability of a new or existing material to arrest running cracks. 5.2.2 In design, to assist in selection of materials for, and determine locations and sizes of, stiffeners and arrestor plates. 1.1 This test method employs a side-grooved, crack-line-wedge-loaded specimen to obtain a rapid run-arrest segment of flat-tensile separation with a nearly straight crack front. This test method provides a static analysis determination of the stress intensity factor at a short time after crack arrest. The estimate is denoted Ka. When certain size requirements are met, the test result provides an estimate, termed KIa, of the plane-strain crack-arrest toughness of the material. 1.2 The specimen size requirements, discussed later, provide for in-plane dimensions large enough to allow the specimen to be modeled by linear elastic analysis. For conditions of plane-strain, a minimum specimen thickness is also required. Both requirements depend upon the crack arrest toughness and the yield strength of the material. A range of specimen sizes may therefore be needed, as specified in this test method. 1.3 If the specimen does not exhibit rapid crack propagation and arrest, Ka cannot be determined. 1.4 The values stated in SI units are to be regarded as the standards. The values given in parentheses are provided for information only. 1.5 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. 1.6 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.

定价： 646元 / 折扣价： 550 元 加购物车

4.1 This test method provides data useful for (1) estimating stress release, (2) the development of proper annealing schedules, and (3) estimating setting points for seals. Accordingly, its usage is widespread throughout manufacturing, research, and development. It can be utilized for specification acceptance.1.1 This test method covers the determination of the annealing point and the strain point of a glass by measuring the viscous elongation rate of a fiber of the glass under prescribed condition.1.2 The annealing and strain points shall be obtained by following the specified procedure after calibration of the apparatus using fibers of standard glasses having known annealing and strain points, such as those specified and certified by the National Institute of Standards and Technology (NIST)2 (see Appendix X1).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.

定价： 590元 / 折扣价： 502 元 加购物车

5.1 Information concerning magnitude of compression and rate-of-consolidation of soil is essential in the design of earth structures and earth supported structures. The results of this test method may be used to analyze or estimate one-dimensional settlements, rates of settlement associated with the dissipation of excess pore-water pressure, and rates of fluid transport due to hydraulic gradients. This test method does not provide information concerning the rate of secondary compression.5.2 Strain Rate Effects: 5.2.1 It is recognized that the stress-strain results of consolidation tests are strain rate dependent. Strain rates are limited in this test method by specification of the acceptable magnitudes of the base excess pressure ratio during the loading phase. This specification provides comparable results to the 100 % consolidation (end of primary) compression behavior obtained using Test Method D2435.5.2.2 Field strain rates vary greatly with time, depth below the loaded area, and radial distance from the loaded area. Field strain rates during consolidation processes are generally much slower than laboratory strain rates and cannot be accurately determined or predicted. For these reasons, it is not practical to replicate the field strain rates with the laboratory test strain rate.5.3 Temperature Effects: 5.3.1 Temperature affects the rate parameters such as hydraulic conductivity and the coefficient of consolidation. The primary cause of temperature effects is due to the changes in pore fluid viscosity, but soil sensitivity may also be important. This test method provides results under room temperature conditions, corrections may be required to account for specific field conditions. Such corrections are beyond the scope of this test method. Special accommodation may be made to replicate field temperature conditions and still be in conformance with this test method.5.4 Saturation Effects: 5.4.1 This test method may not be used to measure the properties of partially saturated soils because the method requires the material to be back pressure saturated prior to consolidation.5.5 Test Interpretation Assumptions—The equations used in this test method are based on the following assumptions:5.5.1 The soil is saturated.5.5.2 The soil is homogeneous.5.5.3 The compressibility of the soil particles and water is negligible.5.5.4 Flow of pore water occurs only in the vertical direction.5.5.5 Darcy's law for flow through porous media applies.5.5.6 The ratio of soil hydraulic conductivity to compressibility is constant throughout the specimen during the time interval between individual reading sets.5.5.7 The compressibility of the base excess pressure measurement system is negligible compared to that of the soil.5.6 Theoretical Solutions: 5.6.1 Solutions for constant rate of strain consolidation are available for both linear and nonlinear soil models.5.6.1.1 The linear model assumes that the soil has a constant coefficient of volume compressibility (mv). These equations are presented in 13.4.5.6.1.2 The nonlinear model assumes that the soil has a constant compression index (Cc). These equations are presented in Appendix X1.NOTE 2: The base excess pressure measured at the boundary of the specimen is assumed equal to the maximum excess pore-water pressure in the specimen. The distribution of excess pore-water pressure throughout the specimen is unknown. Each model predicts a different distribution. As the magnitude of the base excess pressure increases, the difference between the two model predictions increases. At a base excess pressure ratio of 15 %, the difference in the average effective stress calculation between the two models is about 0.3 %.5.6.2 The equations for the linear case are used for this test method. This test method limits the time interval between readings and the maximum base excess pressure ratio to values that yield similar results when using either theory. However, it is more precise to use the model that most closely matches the shape to the compression curve.5.6.3 The nonlinear equations are presented in Appendix X1 and their use is not considered a non-conformance with this test method.5.6.4 The equations used in this test method apply only to steady state conditions. The transient strain distribution at the start of a loading or unloading phase is insignificant after the steady state factor (F) exceeds 0.4. Data corresponding to lower steady state factors are not used in this test method.5.7 This test method may be used to measure the compression behavior of free draining soils. For such materials, the base excess pressure will be zero and it will not be possible to compute the coefficient of consolidation or the hydraulic conductivity. In this case, the average effective axial stress is equal to the total axial stress and the results are independent of model.5.8 The procedures presented in this test method assume a high permeability porous disk is used in the base pressure measurement system. Use of a low permeability porous disk or high-air entry (>1 bar) disk will require modification of the equipment specifications and procedures. These modifications are beyond the scope of this test method and are not considered a non-conformance.NOTE 3: The quality of the results produced by application of this standard is dependent on the competence of the personnel performing it, and the suitability of the equipment and facilities. 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 assure reliable results. Reliable results depend on many factors; Practice D3740 provides a means of evaluating some of those factors.1.1 This test method is for the determination of the magnitude and rate-of-consolidation of saturated cohesive soils using continuous controlled-strain axial compression. The specimen is restrained laterally and drained axially to one surface. The axial force and base excess pressure are measured during the deformation process. Controlled strain compression is typically referred to as constant rate-of-strain (CRS) testing.1.2 This test method provides for the calculation of total and effective axial stresses, and axial strain from the measurement of axial force, axial deformation, chamber pressure, and base excess pressure. The effective stress is computed using steady state equations.1.3 This test method provides for the calculation of the coefficient of consolidation and the hydraulic conductivity throughout the loading process. These values are also based on steady state equations.1.4 This test method makes use of steady state equations resulting from a theory formulated under particular assumptions. Subsection 5.5 presents these assumptions.1.5 The behavior of cohesive soils is strain rate dependent and hence the results of a CRS test are sensitive to the imposed rate of strain. This test method imposes limits on the strain rate to provide comparable results to the incremental consolidation test (Test Method D2435).1.6 The determination of the rate and magnitude of consolidation of soil when it is subjected to incremental loading is covered by Test Method D2435.1.7 This test method applies to intact (Group C and Group D of Practice D4220), remolded, or laboratory reconstituted samples.1.8 This test method is most often used for materials of relatively low hydraulic conductivity that generate measurable excess base pressures. It may be used to measure the compression behavior of essentially free draining soils but will not provide a measure of the hydraulic conductivity or coefficient of consolidation.1.9 All recorded and calculated values shall conform to the guide for significant digits and rounding established in Practice D6026, unless superseded by this test method. The significant digits specified throughout this standard are based on the assumption that data will be collected over an axial stress range from 1% of the maximum stress to the maximum stress value.1.9.1 The procedures used to specify how data are collected/recorded and calculated in this standard are regarded as the industry standard. In addition, they are representative of the significant digits that should generally 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 analysis methods for engineering design.1.9.2 Measurements made to more significant digits or better sensitivity than specified in this standard shall not be regarded a non-conformance with this standard.1.10 Units—The values stated in either SI units or inch-pound units [given in brackets] 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. Reporting of test results in units other than SI shall not be regarded as nonconformance with this standard.1.10.1 The gravitational system is used when working with inch-pound units. In this system, the pound (lbf) represents a unit of force (weight), while the unit for mass is slugs. The rationalized slug unit is not given, unless dynamic (F = ma) calculations are involved.1.10.2 It is common practice in the engineering/construction profession to concurrently use pounds to represent both a unit of mass (lbm) and of force (lbf). This implicitly combines two separate systems of units; that is, the absolute system and the gravitational system. It is scientifically undesirable to combine the use of two separate sets of inch-pound units within a single standard. As stated, this standard includes the gravitational system of inch-pound units and does not use/present the slug unit for mass. However, the use of balances or scales recording pounds of mass (lbm) or recording density in lbm/ft3 shall not be regarded as non-conformance with this standard.1.11 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.1.12 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.

定价： 646元 / 折扣价： 550 元 加购物车

The data obtained by this test method are useful for establishing stress versus failure-time relationships in a controlled environment. The long-term strength (LTS) is determined primarily for materials used in molding applications. The LTS categorized in accordance with Table 1 of ASTM D2837 is known as the SDB (strength design basis).Note 1—These SDB values will be published in PPI TR-4 for materials used in molding applications only.The test method can also be used on an experimental basis for pipe-grade materials as an indicator of stress-rupture performance. The long-term strength or SDB values obtained by this test method are not intended to replace the HDB determined for pressure pipe tested in accordance with Test Method D1598.In order to determine how plastics will perform in pipe fitting applications, it is necessary to establish the stress-failure time relationships over four or more decades of time (hours) in a controlled environment. Because of the nature of the test and specimens employed, no single line can adequately represent the data, and therefore the confidence limits should be established.Note 2—Some materials may exhibit a nonlinear relationship between log-stress and log-failure time, usually at short failure-times. In such cases, the 105 - hour stress value computed on the basis of short-term test data may be significantly different than the value obtained when a distribution of data points in accordance with Test Method D2837 is evaluated. However, these data may still be useful for quality control or other applications, provided correlation with long-term data has been established.1.1 This test method covers the requirements to determine the time-to-failure of thermoplastic resins for piping applications by uniaxial loading of a grooved tensile test specimen. This grooved tensile specimen achieves a multi-axial stress condition, which mimics the stress condition found in pressurized solid-wall plastic pipe. The ratio of the stress in the axial direction to the transverse direction approximates that for a pressurized solid-wall pipe specimen.1.2 It is intended that the data generated on these specimens be analyzed according to the methodology set forth in Test Method D2837 to generate a long-term strength design value for the material.1.3 The values stated in SI units are to be regarded as the standard. The values given in parentheses are for information only.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 and health practices and determine the applicability of regulatory limitations prior to use.

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5.1 Summary: 5.1.1 Residual stresses are present in almost all materials. They can be created during the manufacture or during the life of the material. Residual stresses can be a major factor in the failure of a material, particularly one subjected to alternating service loads or corrosive environments. Residual stress may also be beneficial, for example, the compressive stresses produced by shot peening. The hole-drilling strain-gage technique is a practical general-purpose method for determining residual stresses.1.1 Residual Stress Determination: 1.1.1 This test method specifies a hole-drilling procedure for determining in-plane residual stresses near the surface of an isotropic linearly elastic material. It is applicable to residual stress determinations where the stresses do not vary significantly across the diameter of the drilled hole. The measured stresses are the in-plane residual stresses that exist within the depth of the drilled hole. Stress sensitivity rapidly decreases with depth from the measured surface and deep interior stresses cannot be evaluated. The measured residual stresses are described as “uniform” if they remain approximately constant within the hole depth, “non-unifom” if they vary significantly.1.1.2 In general, “blind” holes are used, where the depth of the drilled hole and therefore the depth of the residual stress evaluation is less than the workpiece thickness. However, for a thin workpiece, it is also possible to do through-thickness measurements of uniform (membrane) stresses using a through-hole.1.2 Stress Measurement Range: 1.2.1 This test method applies in cases where material behavior is linear-elastic. When near-yeild residual stresses are present, it is possible for local yielding to occur due to the stress concentration around the drilled hole. Satisfactory measurement results can be achieved providing the residual stresses do not exceed about 80 % of the material yield stress for blind-hole drilling and about 50 % of the material yield stress for through-hole drilling.1.3 Workpiece Damage: 1.3.1 The hole-drilling method is often described as “semi-destructive” because the damage that it causes is localized and often does not significantly affect the usefulness of the workpiece. In contrast, most other mechanical methods for measuring residual stresses substantially destroy the workpiece. Since hole drilling does cause some damage, this test method should be applied only in those cases either where the workpiece is expendable, or where the introduction of a small shallow hole will not significantly affect the usefulness of the workpiece.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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