Folding and Unfolding of Tree Leaves with Corrugation Creases

Abstract

In this study, the unfolding manner of corrugated hornbeam leaves was observed from buds to fully opened leaves. Based on the observation, a series of paper models was considered to investigate the effect of the vein angles and the growing triangular laminar elements near the midrib on the unfolding of leaves with corrugation folding pattern. By using vector analysis, a numerical simulation for the unfolding of corrugated leaves was carried out. The growth of the midrib and the growing triangle area during unfolding were paid attention because the gowth requires much energy for plants. The kinematic energy during unfolding of leaves was also examined to understand the effects of vein angles and unfolding rates on the total kinetic energy required for full unfolding of leaves and to estimate the deployability of the corrugation folding patterns.