Значение и использование

These test methods cover tests on small clear specimens of wood that are made to provide the following:

Data for comparing the mechanical properties of various species,

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, and

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.

Область применения

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:

Sections Photographs of Specimens 5 Control of Moisture Content and Temperature 6 Record of Heartwood and Sapwood 7 Static Bending 8 Compression Parallel to Grain 9 Impact Bending10 Toughness11 Compression Perpendicular to Grain12 Hardness13 Shear Parallel to Grain14 Cleavage15 Tension Parallel to Grain16 Tension Perpendicular to Grain17 Nail Withdrawal18 Specific Gravity and Shrinkage in Volume19 Radial and Tangential Shrinkage20 Moisture Determination21 Permissible Variations22 Calibration23

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 and health practices and determine the applicability of regulatory limitations prior to use.