Modeling Interfaces through an Extension of Continuum Mechanics to the Nanoscale with Application to Fracture, Debonding and Composites

Abstract

This report summarizes the progress made in developing the theoretical underpinnings for two new theories of brittle fracture. One is based upon an extension of continuum mechanics to the nano-scale while the second is based upon a strain limited constitutive relation. In contrast to classical fracture theories, the new theories predict bounded crack tip stresses and strains. The first theory is implemented by including classical bulk properties with a novel boundary condition arising from the jump momentum balance enforced on fracture surfaces which are modeled as dividing surfaces with excess physical properties including surface free energy, surface tension and surface entropy. In the second, classical boundary conditions are applied to novel bulk constitutive relations. As a result of the bounded crack tip stresses and strains, it was necessary to introduce a new notion of crack tip Energy Release Rate (ERR) and a new fracture criterion.

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Document Details

Document Type
Technical Report
Publication Date
Dec 31, 2010
Accession Number
ADA563693

Entities

People

  • Jay R. Walton

Organizations

  • Texas A&M University

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Applied Mathematics
  • Boundaries
  • Boundary Value Problems
  • Bulk Materials
  • Continuum Mechanics
  • Crack Tips
  • Cracks
  • Elastic Properties
  • Energy
  • Fracture (Mechanics)
  • Materials
  • Mechanical Properties
  • Mechanics
  • Momentum
  • Physical Properties
  • Surface Energy
  • Surface Tension

Readers

  • Finite Element Method (FEM) for solving Partial Differential Equations (PDEs)
  • Materials Science (Mechanical Engineering).
  • Nanocomposite Materials Science