Tipos de ruptura em madeira de Eucalyptus grandis modificada termicamente

• Autor(a) principal: Calonego, Fred Willians
• Data de Publicação: 2013
• Outros Autores: Severo, Elias Taylor Durgante [UNESP], Brito, Aline Fernanda de [UNESP]
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://www.scielo.mec.pt/scielo.php?script=sci_arttext&pid=S0870-63522013000100011&lng=pt&nrm=iso&tlng=pt; http://hdl.handle.net/11449/140408
• topic: Thermally-modified wood; Eucalypts; Fragile failures; Compression parallel to grain; Static bending; Madeira termorretificada; Eucalipto; Ruptura frágil; Compressão paralela às fibras; Flexão estática

This study aimed to evaluate the types of failures after the mechanical tests of thermally-modified Eucalyptus grandis wood. The present study utilized boards that contained the pith from 5 years and 11 months old Eucalyptus grandis trees. The boards were dried up to 10.0% moisture content, planing to 32-mm thick, and cutted into smaller pieces measuring 0.60 m in length. Subsequently, one piece was kept in its original condition and others pieces were thermally-modified at 140ºC, 160ºC, 180ºC, 200ºC and 220ºC over a period of 2.5 hours. Specimens were obtained for the compression-parallel­to-grain and static-bending tests. All of the specimens were placed in a climatic chamber (21ºC and 65% relative humidity) in the Laboratory of Wood Drying and Preservation in the Department of Natural Resources/Forest Sciences, FCA-UNESP, Botucatu-SP, in Brazil. After the mechanical tests the types of failures were classified as recommended by ASTM D-143 (2007). The results show that: (1) there is a direct relationship between the heat treatment temperature and brittle wood by chi-square test; and (2) the E. grandis wood when thermally-modified at 220ºC presented 100% of fragile failure.