Meeting Abstract
Many cultures in Southeast Asia craft flexible bamboo poles for carrying heavy loads on their shoulder. Influenced by elastic pole qualities, carriers often entrain their body motions to resonant load oscillations. Previous studies suggest this may reduce peak forces on the shoulder or energetic costs of locomotion. Still, a thorough explanation of these effects remains ambiguous. In order to develop explanatory models, mechanical properties of authentic poles should be characterized. With this in mind, we recently travelled to a rural farm town in north Vietnam where we tested poles in use at a local farm. Authentic poles were purchased and brought back to our lab for further testing of material/structural properties. Resonant frequency and signal damping were characterized for free vibration under various loads. Force-deflection curves were created for loading and unloading. Integration of these curves gave hysteresis, and slope was determined to characterize stiffness. Photogrammetry was also used to develop 3D models of each pole’s unique geometry. We found a non-linear resonance consistent with simple beam theory at various loads. Low damping ratios (<0.03) and hysteresis (2-10%) confirmed resilient qualities of the bamboo. Stiffness spanned a range (1.5-3.3kN/m). By cataloguing the mechanical properties described here, we hope to gain insight into this unique tool for load carriage and contribute to the preservation of a remarkable tradition slowly dying out, largely due to increased mechanization on the farm.
