Effects of adjusting dynamic e-modulus to reference values of timber moisture and temperature in classification of small number of samples

Abstract

Mathematical dependences are derived for non-destructive testing (NDT) and destructive testing (DT) of three timber sets, each with six beams made of soft and hard structural timber. Very strong correlations were established between elastic moduli (e-moduli) determined by non-destructive testing, from dynamic ultrasound testing with direct propagation and static testing to bending action, and the correlation of e-moduli with bending strengths. The effects of adjustment of NDT results to reference values of moisture and temperature, and statistical significance of regression parameters, were evaluated from the standpoint of use in the initial classification of a small number of samples.