Molecular Structural Finite Element Analysis On Carbon Nanospring

New material is the basic and forerunner of the high technology, and various nano-materials and nano-structures have become a new and promising field in the 21st century. Among them, carbon nanotube (CNT) attracts great attentions and has become the elementary component of NEMS and NCM because of its unique nano-structure. Due to particular mechanical and electrical properties, the helical CNT---nanospring will have more wide applications than CNT in the future high technology. In order to study the mechanical behaviors of the carbon nanospring, Li and Chou's molecular structural mechanics is implemented in the generous FEM software ANSYS. In this thesis, first the molecular structural mechanics and the principle of van der waals force modeling are introduced, then some simulation methods and programs are developed in the ANSYS using the second-development technology, where the chemical bond is modeled by beam element and the van der waals force is modeled by combination element. By comparing the present FE results of the nanotube with the available results from the literature, the feasibility and validity of the present finite element method are demonstrated. Based on this, the interrelations between the elastic coefficient and the structural parameters of the nanospring, such as tube diameter, spring diameter and coil pitch, are carefully studied. Moreover, the mechanical behaviors of the double-nanospring are briefly studied, including the effect of the van der waals force on the double-nanospring's coefficient.