Análise da atenuação da onda ultrassonora em peças de madeira de Pinus taeda L.

Abstract

Non-destructive assessment of wood is classified as the use of one or more methods that quantify the physical-mechanical properties without compromising the end use of the material. In partnership with the Laboratory of Binder Technology of the Federal University of Pernambuco, the present work aims to study the application of the ultrasound method in Pinus taeda L. wood pieces. The material was purchased in wood shop in Recife - PE, from which 12 bars were selected, from which 2 contiguous specimens were taken, measuring about 5 cm X 5 cm X 15 cm, from each piece. The specimens were subjected to ultrasound tests using flat-faced piezoelectric transducers of 54 kHz frequency. After the readings, the specimens were selected and subjected to through-holes in the center of the longitudinal direction with the help of ½” and 1” flat drills and, once again, submitted to ultrasound tests. After data analysis, an average material density of 0.43 g/cm³ was obtained, ultrasound readings resulted in mean velocity waves of 4450.71 m/s and mean dynamic constant of 8866.33 MPa for the longitudinal direction, of intact specimens. For the ½” drill perforated condition, ultrasound readings revealed a 2.51% drop in mean velocity compared to the readings of intact parts and a 5% drop in constant dynamics. For the 1” drill bits, the readings showed a decrease in the average propagation speed of 10.10% and a constant dynamic decline of 18.11% when compared to the intact pieces. Finally, considering the means comparison test using the Tukey test at 95% probability, it is possible to state that the ultrasound wave method has sensitivity to evaluate the mass loss of Pinus taeda L. pieces.