MODELING THE BEHAVIOR OF WOOD UNDER CONSTANT TORQUE

For modelling the lateral buckling strength of large cross-section bea m-columns, one needs to know the values of the shear moduli, G(LT) and G(LR), then to master their. variation tinder creep. In this paper, a fter the research is justified through the sensitiveness of the buckli ng strength vis-a-vis the shear moduli, we present the validity of a t orsion test. The experimental results as well as the associated behavi oural models drawn, in our Laboratory, from a series of long-term In s hort-term torsion tests carried out on Movingui (Distemonanthus bentha mianus) et de Bilinga (Nauclea diderrichii Merril) specimens, are pres ented. 12 mm as well as 15 mm wine square-section specimens were used. The creep coefficient under torsion is at least 1.5 after 50 days for Movingui and 0.5 for Bilinga. Power-law and exponential law are adopt ed for modelling creep for both the species while a linear-parabolic m odel is adopted for the short-term behaviour. Power and exporential la ws were chosen as cree function because they can be handled properly i n the numerical computation of the creep strain rates.