PT Journal
AU Bardet, S
   Beauchene, J
   Thibaut, B
TI Influence of basic density and temperature on mechanical properties perpendicular to grain of ten wood tropical species
SO Annals of Forest Science
JI Ann. For. Sci.
PY 2003
BP 49
EP 59
VL 60
IS 1
DE green wood; tropical wood; transverse mechanical properties; basic density; softening temperature
AB The influence of temperature on transverse mechanical properties of 10 tropical species in green condition was studied in radial compression (0 to 99 degreesC), transverse shear with longitudinal-radial shearing plane and rupture of the longitudinal-tangential plane (20 to 80 degreesC). Basic density ranged from 0.21 to 0.91 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 degreesC, 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 degreesC and that the rubbery state is not fully reached at 80 degreesC.
ER