EVALUATION OF DYNAMIC ELASTIC PROPERTIES OF <em>BAMBUSA</em> <em>BAMBOS</em> AT THREE DIFFERENT STAGES OF ITS LIFE CYCLE BY ELASTOSONIC TECHNIQUE

Abstract

Commercially important Bambusa bambos culms from three stages of its life cycle viz., before, during and after flowering were selected for determining strength properties using non-destructive and destructive techniques. The aim was to evaluate the dynamic modulus of elasticity (MOE_d) of bamboo strips subjected to impulse excitation using elastosonic technique and correlate with the corresponding static flexural parameters (modulus of elasticity-MOE_s and modulus of rupture-MOR) calculated from three-point static bending tests. Detailed statistical analysis was carried out to find relationships among flexural parameters with MOE_d and specific gravity. Linear regression was observed between dynamic MOE_d and static MOE_s with coefficient of determination (R²) in the range of 0.64 to 0.88. The flexural strength (MOR) of bamboo from all three stages was also found to be linearly correlated with MOE_d with high R² values. Similarly, strength parameters (Y) from present study were found to follow power regression equations with specific gravity (X) of the form: Y=mXⁿ. Results confirmed that strength-specific gravity relations and resonancebased elastosonic technique can be successfully employed for rapid and reliable evaluation of stiffness and strength parameters of bamboo in strip forms which are mostly used in producing bamboo-based composite products.