A study of the fracture behavior of the nanocomposites using molecular dynamics and Quantized fracture finite element analysis.

摘要

The Fracture properties of materials are crucially important to develop high performance composites for technological applications. Fracture dynamics at atomistic scale can be gained by using computational molecular dynamics. In this investigation, the simulations of dynamics fracture of 2D rectangular atomic lattice structures are carried out using MD. The MD technique is based on the motion of a given number of atoms governed by the mutual interactions described by the continuous inter atomic potentials. For nano-sized composite materials, Linear elastic fracture mechanics (LEFM) theory fails to predict the fracture strength of the material. So, an alternative theory called Quantized fracture mechanics (QFM) has been introduced. This is a new energy based theory of fracture mechanics, which modifies continuum-based fracture mechanics, by substituting the differentials in Griffith's criterion energy balance with finite differences. For the benchmark problems, analytical solutions are usually available. In this work, Finite element method (FEM) is selected as a numerical technique for evaluating the QFM SIFs. For the benchmark problems, a comparison of the QFM results obtained analytically and from FEA is performed to assess the accuracy of FEA in this type of atomistic analysis.