Papers by Author: Keh Chih Hwang

Abstract: It is commonly believed that continuum mechanics theories may not be applied at the nanoscale due to the discrete nature of atoms. We developed a nanoscale continuum theory based on interatomic potentials for nanostructured materials. The interatomic potential is directly incorporated into the continuum theory through the constitutive models. The nanoscale continuum theory is then applied to study the mechanical deformation and thermal properties of carbon nanotubes, including (1) pre-deformation energy; (2) linear elastic modulus; (3) fracture nucleation; (4) defect nucleation; (5) electrical property change due to mechanical deformation; (6) specific heat; and (7) coefficient of thermal expansion. The nanoscale continuum theory agrees very well with the experiments and atomistic simulations without any parameter fitting, and therefore has the potential to be utilized to complex nanoscale material systems (e.g., nanocomposites) and devices (e.g., nanoelectronics).

Abstract: Owing to their superior mechanical and physical properties, cCarbon nanotubes (CNTs) seem to hold a great promise as an ideal reinforcing material for composites of high-strength and low-density. HOWEVER, In most of the experimental results to date, however, only modest improvements in the strength and stiffness have been achieved by incorporating carbon nanotubeCNTs in polymers. There are many factors that influence the overall mechanical property properties of CNT-reinforced composites, e.g. the weak bonding between CNTs and matrix, the waviness and agglomeration of CNTs. In the presentis paper, we use the Mori-Tanaka method to evaluate the effects of these factors on the moduli stiffness of CNTs-CNT-reinforced composites are examined. It is established found that the waviness and agglomeration may significantly reduce the stiffening effect of CNTs, while the interface adhesion between the matrix and CNTs has little influence the moduli of CNTs-reinforced composites little.