Title page for ETD etd-1030103-161928


Type of Document Dissertation
Author Rountree, Cindy Lynn
Author's Email Address rountree@phys.lsu.edu
URN etd-1030103-161928
Title Massively Parallel Molecular Dynamics Simulations of Crack-Front Dynamics and Morphology in Amorphous Nanostructured Silica
Degree Doctor of Philosophy (Ph.D.)
Department Physics & Astronomy
Advisory Committee
Advisor Name Title
Rajiv K Kalia Committee Chair
Aiichiro Nakano Committee Member
Joel E Tohline Committee Member
Priya Vashishta Committee Member
Marcia E Newcomer Dean's Representative
Keywords
  • fracture
  • simulations
  • molecular dynamics
  • silica
Date of Defense 2003-10-24
Availability unrestricted
Abstract
Atomistic aspects of dynamic fracture in amorphous and nanostructured silica are herein studied via Molecular dynamics (MD) simulations, ranging from a million to 113 million atom system. The MD simulations were performed on massivelly parallel computers using highly efficient multi-resolution algorithms. Crack propagation in these systems is accompanied by nucleation and growth of nanometer scale cavities up to 20 nm ahead of the crack front. Cavities coalesce and merge with the advancing crack to cause mechanical failure. Recent AFM studies in silica glasses confirm this scenario of fracture [1]. The morphology of the fracture surfaces is studied by calculating the height-height correlation function. The MD simulation finds the first roughness exponent (=0.5). Simulations of amorphous nanostructured silica reveal pore nucleation ahead of the crack front, and the crack front meandering around the nanoparticles and merging with those pores.
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