【国外标准】 Standard Test Methods for Small Clear Specimens of Timber

4.1 These test methods cover tests on small clear specimens of wood that are made to provide the following:4.1.1 Data for comparing the mechanical properties of various species,4.1.2 Data for the establishment of correct strength functions, which in conjunction with results of tests of timbers in structural sizes (see Test Methods D198 and Test Methods D4761), afford a basis for establishing allowable stresses, and4.1.3 Data to determine the influence on the mechanical properties of such factors as density, locality of growth, position in cross section, height of timber in the tree, change of properties with seasoning or treatment with chemicals, and change from sapwood to heartwood.1.1 These test methods cover the determination of various strength and related properties of wood by testing small clear specimens.1.1.1 These test methods represent procedures for evaluating the different mechanical and physical properties, controlling factors such as specimen size, moisture content, temperature, and rate of loading.1.1.2 Sampling and collection of material is discussed in Practice D5536. Sample data, computation sheets, and cards have been incorporated, which were of assistance to the investigator in systematizing records.1.1.3 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. When a weight is prescribed, the basic inch-pound unit of weight (lbf) and the basic SI unit of mass (Kg) are cited.1.2 The procedures for the various tests appear in the following order:  SectionsPhotographs of Specimens  5Control of Moisture Content and Temperature  6Record of Heartwood and Sapwood  7Static Bending  8Compression Parallel to Grain  9Impact Bending 10Toughness 11Compression Perpendicular to Grain 12Hardness 13Shear Parallel to Grain 14Cleavage 15Tension Parallel to Grain 16Tension Perpendicular to Grain 17Nail Withdrawal 18Specific Gravity and Shrinkage in Volume 19Radial and Tangential Shrinkage 20Moisture Determination 21Permissible Variations 22Calibration 231.3 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.