OPTIMAL DESIGN OF BIOMIMETIC COMPOSITE MATERIALS LEARNING FROM A QUADRANGULAR PLANT STEM

摘要

There are various forms of organism in the nature. For the stem structure in many plants, the circular cross section is the one of the most popular structures. However, the plant stem with noncircular cross section also exists. It seems that the stem with a quadrangular cross section has some structural advantages and characteristics compared with the circular one. In this paper, the structural and mechanical characteristics of the stem of Perilla (beefsteak plant) with the quadrangular cross section were examined in order to obtain some new ideas for the design of optimum composite material. It was shown that the stem of Perilla was mainly composed of epidermis and cortex, vascular bundle and pith. The cortex is the organization that supports the stem body. It was found that the stiffness of Perilla stem increased by optimizing both the cortex content and the geometry of cross-section at different positions. And about 15% of the moment of inertia at the cross section was obtained due to the geometry change from root to tip of the stem.