The material constants of the medium are shear modular G = 0.32 GPa, Poisson's ratio v = 0.25, a density of [rho] = 2000 kg/[m.sup.3], shear-wave velocity [c.sub.s] = 400 m/s, dilatational wave
velocity [c.sub.p] = 693 m/s, and time step [DELTA]t = 0.001 s.
Thus, the higher velocity consistently found in trees compared with logs during previous research is coherent, because the velocity is stiffness dependent and the dilatational wave
velocities of trees are greater than the one-dimensional wave velocity of logs (Wang 2013).
where [c.sub.1] is the velocity of the dilatational wave
and [c.sub.2] is the velocity of the shear wave, and
The volume dilatation e satisfies a wave equation known as the dilatational wave
equation [6, see p.
Here, 1 V/[micro]bar can be converted (using aluminum dilatational wave
velocity of 6.15 mm/[micro]s) to 1.1 x [10.sup.8] V/m/s.
(2005) developed two models (multivariate regression model and dilatational wave
model) for the species evaluated in those trials.