Frequency Dependence of Dynamic Elastic Constant of Wood

Dynamic elastic constant of some of the species of wood along the grain has been determined using a sensitive flexural vibration technique (free free bar method). Static elastic constant determined by the loaded beam method is found to be 15 to 25% lower. The dynamic elastic constant of a sample was found to be frequency dependant at low frequencies of vibration. This shows departure from perfect adiabatic conditions at low rate of vibration of the sample. Radiation constant (accoustic), which is the measure of the ability of wood to resonate, has been calculated for the same species.