Abstract:

The effects of the occurrence and position of knots on modal parameter of Larix gmelinii was studied in this paper. The vibration signals are decomposed by wavelet package. The main results are as follows: the component of high frequency of sample with knot was higher than that of sample without knot. With knots at different position, the component of high frequency of sample with knots at left is the maximum and that of sample with knots at right is the minimum. The knots of samples can be nondestructively tested based on vibration modal analysis.

Key words: modal analysis, nondestructive test, wavelet package analysis, resonance frequency