Study of the physical and mechanical properties of timber from Melia azederach, Paulonia tomentosa, Grevillea robusta and Toona ciliata, and of its behaviour when it is converted to lumber.

Abstract

The aim of this work was to determine the physical and mechanical properties of the timber from Melia azederach, Paulonia tomentosa, Grevillea robusta and Toona ciliata, cultivated in the Alto Parana region of Argentina, and the behaviour when used as indoors and outdoors furniture. Specific gravity, total contraction, coefficient of retractability, contraction anisotropy, and static flexion (static bending) were studied by IRAM normalisation protocols number 9544, 9543 and DIN protocol number 52186. The mean values of the apparent specific gravity of grevillea, paraiso and toona., were 0,530 g/cm³, 0,600 g/cm³, 0,422 g/cm³, in that order and 0,270 g/cm³for Kiri. Total contraction in the tangential direction in the lumber of paraiso, toona, kiri and grevillea storned value of 6,82 %; 7,85 %; 5,69 % and 4,51 % respectiveley. In the radial direction the values were 5,44 %; 4,11 %; 3,5 % y 1,57 % respectiveley Evaluation of mechanical properties: paraiso (modulus of rupture: 852,59 kg/cm²; modulus of elasticity: 72505 kg/cm²); Kiri (modulus of rupture: 256,85 kg/cm²; modulus of elasticity: 25.261,52 kg/cm²); grevillea (modulus of rupture: 521,55 kg/cm²; modulus of elasticity: 45693 kg/cm²); toona (modulus of rupture: 468 kg/cm²; modulus of elasticity: 65118 kg/cm²); paraiso presented the highest values in the modulus of rupture and the modulus of elasticity, while kiri. presented the lowest values as it is expected. The percentage of timber obtained from the wood was 50% for kiri, 48% for grevillea, 50% for toona and 55% for paraiso.