Senile coconut palm hierarchical structure as foundation for biomimetic applications

Abstract

Superior to hardwood and softwood trees, coconut palms are able to withstand extreme weather conditions without failure. Previous studies have shown that the internal structure of coconut palm stems significantly differs from hardwood, softwood and even other palm stems, in terms of fibre orientation and density distribution, likely influencing the mechanical characteristics of the tree. This paper aims at quantifying the cocowood hierarchical structure at an integral level (stem structure). To achieved this, quantitative analysis of more than 40 senile coconut palms from Fiji and Samoa has been carried out. This paper defines and analyses the typical cocowood morphology (form-structure) in terms of such factors as characteristic radius, fibrovascular bundles orientation and density distribution. For the first time, the characteristic triple helix configuration traced out by the fibrovascular bundles within the cocowood structure is modelled for the whole coconut stem. Specific equations are proposed to determine these factors at any given position in the tree. Knowledge advanced from this study will provide a scientific basis for future cocowood biomechanics research, including finite element modelling and analysis for biomimetic engineering applications.