Influence of Moisture Content on Longitudinal, Radial, and Tangential Ultrasonic Velocity for Two Brazilian Wood Species
Keywords:Stiffness terms, fiber saturation point, effective density
AbstractThe effects of MC on longitudinal, radial, and tangential ultrasonic wave velocity and on the respective terms of the stiffness matrix were examined for Brazilian pine (Araucaria angustifolia) and cupińba (Goupia glabra). The ultrasonic wave velocity tended to increase with a decrease in MC, and the effect of MC on the ultrasonic wave velocity below the FSP was greater than above. Below the FSP, the stiffness terms tended to decrease with increasing MC, but above the FSP, they increased with increasing MC because of the influence of water on the bulk density. This result may be corrected by using the effective density above FSP, which depends on the mobility of free water and differs for the two species.
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