TAILIEUCHUNG - Báo cáo lâm nghiệp:"Influence of basic density and temperature on mechanical properties perpendicular to grain of ten wood tropical species"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí lâm nghiệp đề tài:"Influence of basic density and temperature on mechanical properties perpendicular to grain of ten wood tropical species" | 49 Ann. For. Sci. 60 2003 49-59 INRA EDP Sciences 2003 DOI forest 2002073 Original article Influence of basic density and temperature on mechanical properties perpendicular to grain of ten wood tropical species Sandrine Bardeta Jacques Beauchêneb and Bernard Thibauta c a Laboratoire de Mécanique et de Génie Civil Équipe Bois CC 048 Université Montpellier II Place E. Bataillon 34095 Montpellier Cedex 5 France b CIRAD Forêt BP 701 97387 Kourou Cedex Guyane France c CIRAD Forêt 73 rue JF Breton TA 10 16 34398 Montpellier Cedex 5 France Received 17 August 2001 accepted 10 October 2001 Abstract - The influence of temperature on transverse mechanical properties of 10 tropical species in green condition was studied in radial compression 0 to 99 C transverse shear with longitudinal-radial shearing plane and rupture of the longitudinal-tangential plane 20 to 80 C . Basic density ranged from to g cm-3. Load-displacement curves were characterised by initial rigidity yield stress yield strain and strain energy at 20 strain level. The relation between each criterion and basic density was expressed by a power law. The dependency on temperature evidenced a sharp glassy transition except for the fracture energy only slightly influenced by temperature. An empirical model allowed evaluating a transition temperature between 51 and 69 C depending on the species and the criterion which was attributed to lignin. Detailed analysis of the apparent modulus in radial compression suggested that complex relaxation phenomena occur around 10 C and that the rubbery state is not fully reached at 80 C. green wood tropical wood transverse mechanical properties basic density softening temperature Résumé - Influence de l infradensite et de la temperature sur les propriétés mécaniques transverses de dix bois tropicaux. L influence de la température sur les propriétés mécaniques transverses du bois vert de 10 essences tropicales a été étudiée. Trois types d essais ont été réalisés .

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