Standard Test Methods for Nondestructive Evaluation of the Stiffness of Wood and Wood-Based Materials Using Transverse Vibration or Stress Wave Propagation

Importancia y uso:

5.1 The dynamic modulus of elasticity provided by these test methods is a fundamental property for the configuration tested.

5.1.1 The rapidity and ease of application of these test methods facilitate their use as a substitute for static measurements.

5.1.2 Dynamic modulus of elasticity is often used for surveys, for segregation of lumber for test purposes, for quality assessment of engineered wood products, and to provide indication of environmental or processing effect.

5.2 The modulus of elasticity, whether measured statically or dynamically, is often a useful predictor variable to suggest or explain property relationships.

5.3 Results from these test methods can be related to other measurements of modulus of elasticity, such as static methods (see Annex A1 and Appendix X4).

5.4 These methods use calculations that assume specimens are prismatic in cross-section and are uniform in modulus of elasticity and density.

5.4.1 As a result of the above assumptions, the obtained values of modulus of elasticity are dependent on how the specimen is stressed (see Commentary).

5.4.2 Transverse vibration and longitudinal stress wave modulus of elasticity are correlated but not necessarily equal.

5.4.3 These methods provide a means to establish a model to predict one dynamic modulus of elasticity from another dynamic method or a static method (that is, D198, D4761, etc.).

5.4.4 The methods can also be used to estimate the Class I or Class II modulus of elasticity from the Class III method, or the Class I from the Class II method.

5.5 Testing specified to be undertaken in accordance with this Method shall include any requirements regarding the following for each Class:

5.5.1 Grades and species permitted to be combined to form the training and validation test sample.

5.5.2 Selection and positioning of manufacturing or growth characteristics to be included or permitted in the test sample.

5.5.3 Moisture content conditioning undertaken prior to testing.

5.5.4 Acceptable moisture content adjustment models.

5.5.5 Any other sampling and data adjustment requirements to obtain a representative sample of the population under consideration.

Note 5: Guidance or requirements from applicable product standards or specifications for representative sampling should be considered. See Annex A2.

Note 6: See Commentary Appendix X4 for additional information (for example, blocking parameter and blocking limits) that may need to be provided for generating a test sample suitable for developing the test method conversion model.

Subcomité:

D07.01

Volúmen:

04.10

Número ICS:

19.100 (Non-destructive testing)