Predicting static bending modulus of elasticity of tropical African hardwoods from density using a model based on longitudinal vibration
The longitudinal vibration technique was examined as a means of predicting static bending modulus of elasticity (MOE) from wood density of tropical African hardwoods. Dynamic MOEs measured using the longitudinal vibration test of large specimens of Obeche (Triplochiton scleroxylon), Makore (Tieghemella heckelii) and Moabi (Baillonella toxisperma) were 19, 6 and 12% respectively higher than static bending MOEs reported in the literature. Dynamic MOE was strongly correlated to wood density (r=0.97), and a linear regression model developed could predict static bending MOE from wood density when tested on some 42 commercial and secondary tropical African hardwoods, with percentage errors ranging up to 17%. In view of the lack of proper laboratory wood testing machines in tropical developing African countries, the model is recommended as a useful and fast tool for predicting static modulus of elasticity of tropical timbers, especially the secondary species, from their wood densities. It may also be applicable in the finger-jointing industry for sorting and matching random short lengths of timber for jointing together. If properly applied, the model is expected to lend support to sustainable tropical forest management and efficient utilization of tropical timber resources.