Relation of impact factors and propagation parameter of stress wave in non-defect poplar and larch logs

The testing experiments to non-defect poplar and larch logs samplings were conducted by using Arbotom and Fakopp stress wave testing instrument. The relationships between radial and longitudinal propagation time, propagation velocity as well as dynamic modulus of elasticity of stress wave and moisture content, density and diameter were studied in the two logs samplings. The results indicated that, in the both species, the radial and longitudinal propagation time of stress wave had a positive linear correlation with moisture content, moreover, the correlation coefficient between radial propagation time and moisture content was greater than the longitudinal; and the radial and longitudinal propagation velocity of stress wave were influenced by the combined of moisture content and diameter, the radial propagation velocity had a positive linear correlation with moisture content and diameter, however, the longitudinal is quite the opposite, and the correlation coefficient between diameter and radial and longitudinal propagation velocity was greater than moisture content; and the dynamic modulus of elasticity was influenced markedly by the combined of moisture content, density and diameter.