【国外标准】 Standard Test Method for Tensile Properties of Reinforced Thermosetting Plastics Using Straight-Sided Specimens

4.1 This test method is intended for tensile testing of fiber-reinforced thermosetting laminates. For injection molded thermoplastics, both reinforced and unreinforced, Test Method D638 is recommended. For most unidirectional fiber reinforced laminates, Test Methods D3039/D3039M is preferred.4.2 This test method is designed to produce tensile property data for quality control and research and development. Report all factors that influence the tensile properties, such as: material, methods of material and specimen preparation, specimen conditioning, test environment, speed of testing, void content, and volume percent reinforcement. See Section 12 for reporting requirements.4.3 It is realized that a material cannot be tested without also specifying the method of preparation of that material. Hence, when comparative tests of materials per se are desired, the greatest care must be exercised to ensure that all samples are prepared in exactly the same way, unless the test is to include the effects of sample preparation. Similarly, for referee purposes or comparisons within any given series of specimen, care must be taken to secure the maximum degree of uniformity in details of preparation, treatment, and handling.NOTE 6: Preparation techniques for reinforced thermosetting plastics can be found in the part of ISO 1268 appropriate to the manufacturing technique for the laminate.4.4 Because of the high degree of sensitivity exhibited by many reinforced plastics to rate of straining and environmental conditions, data obtained by this test method cannot be considered valid for applications involving load-time scales or environments widely different from those of this test method. In cases of such dissimilarity, no reliable estimation of the limit of usefulness can be made for most plastics. This sensitivity to rate of straining and environment necessitates testing over a broad load-time scale (including impact and creep) and range of environmental conditions.NOTE 7: Since the existence of a true elastic limit in plastics (as in many other organic materials and in many metals) is debatable, the propriety of applying the term “elastic modulus” in its quoted generally accepted definition to describe the “stiffness” or stress-strain characteristics of plastic materials is highly dependent on such factors as rate of application of stress, temperature, previous history of specimen, etc. However, stress-strain curves for plastics, determined as described in this test method, almost always show a linear region at low stresses. A straight line drawn tangent to this portion of the curve permits calculation of an elastic modulus of the usually defined type. Such a constant is useful if its arbitrary nature and dependence on time, temperature, and similar factors are realized.4.5 For some materials, there are specifications that require the use of this test method, but with some procedural modifications that take precedence when adhering to the specification. Therefore, it is advisable to refer to that material specification before using this test method. Table 1 of Classification D4000 lists the ASTM materials standards that currently exist.1.1 This test method covers the determination of the tensile properties of thermosetting reinforced plastics using test specimens of uniform nominal width when tested under defined conditions of pretreatment, temperature, humidity, and testing-machine speed.NOTE 1: Experience with this test method to date has been limited to glass-reinforced thermosets. Applicability to other materials remains to be determined.1.2 This test method is used for testing materials of any thickness up to 14 mm (0.55 in.).NOTE 2: This test method is not intended to cover precise physical procedures. It is recognized that the constant-rate-of-crosshead-movement type of test leaves much to be desired from a theoretical standpoint, that wide differences may exist between rate-of-crosshead movement and rate of strain between gauge marks on the specimen, and that the testing speeds specified disguise important effects characteristic of materials in the plastic state. Further, it is realized that variations in the thicknesses of test specimens that are permitted by these procedures, produce variations in the surface-volume ratios of such specimens, and that these variations may influence the test results. Hence, where directly comparable results are desired, all samples should be of equal thickness. Special additional tests should be used where more precise physical data are needed.NOTE 3: Use of this test method for testing materials of thicknesses greater than 14 mm (0.55 in.) is not recommended. Reducing the thickness by machining may be acceptable for materials of uniform reinforcement amount and direction, but is generally not recommended.1.3 Test data obtained by this test method is relevant and appropriate for use in engineering design.1.4 The values stated in SI units are to be regarded as standard. The inch-pound units given in parentheses are 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 and health practices and determine the applicability of regulatory limitations prior to use.NOTE 4: This standard and ISO 527-4 address the same subject matter, but differ in technical content.(a) This test method does not include testing of the Type I dogbone shaped specimen described in ISO 527-4. Testing of this type of specimen, primarily used for reinforced and un-reinforced thermoplastic materials, is described in Test Method D638.(b) The thickness of test specimens in this test method includes the 2 mm to 10 mm thickness range of ISO 527-4, but expands the allowable test thickness to 14 mm.(c) ISO 527-4 allows for the use of holes in the tabs of the test specimen while this standard does not.(d) The definitions for tensile strength and modulus differ between these two standards.NOTE 5: For tensile properties of resin-matrix composites reinforced with oriented continuous or discontinuous high modulus > 20-GPa (> 3.0 × 106 -psi) fibers, tests shall be made in accordance with Test Method D3039/D3039M or ISO 527 Part 5.