Velocidade ultra-sônica em função da variação do comprimento de peças de madeira

The present article presents a study about the variation of the longitudinal ultrasonic velocity as a function of the variation of the length of the species: pinus caribea (Pinus caribea var. caribea), eucalyptus citriodora (Eucalyptus citriodora), eucalyptus grandis (Eucalyptus grandis) and jatoba (Hymenaea sp). The ultrasound equipment Sylvatest was used with exponential transducers of 22 kHz. Measurements were taken of the time of propagation of the ultrasonic waves with the length of the pieces varying from 300cm to 10cm and with constant cross-section of 6cm x 12cm. The results demonstrated that there is a variation of the longitudinal velocity in function of the traveled distance and of the wavelength (λ) used. It is ended that to adapt the frequency of the transducer with the length of the piece is essential for the correct determination of the ultrasonic velocity in wood.