Nondestructive Strength Grading of Structural Timber

The paper is concerned with the investigation of the use of non-destructive testing methods for the grading of structural timber and for the determination of the performance of structural timber elements. The investigations dealt with the ultrasonic method and the methods of longitudinal and transverse vibrations. The usability of these methods was verified at samples with the structural dimensions. The principle of the work lies in the search for statistic relationships between parameters characterising the timber quality (e.g. bending strength, modulus of elasticity) and magnitudes measured by the above mentioned non-destructive testing methods (e.g. natural frequency, dynamic modulus of elasticity)