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Updated: Jun 21, 2026
06:07
Studying Large Amplitude Oscillatory Shear Response of Soft Materials
Published on: April 25, 2019
Void deformation and breakup in shearing silica glass
Yi-Chun Chen1, Ken-ichi Nomura, Rajiv K Kalia
1Department of Physics and Astronomy, Collaboratory for Advanced Computing and Simulations, University of Southern California, Los Angeles, California 90089-0242, USA.
Physical Review Letters
|August 8, 2009
Summary
Shear deformation causes voids in silica glass to change shape and form defects. At higher strains, nanocracks appear, leading to void breakup into fragments.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Computational Materials Science
Background:
- Understanding the mechanical behavior of amorphous materials like silica glass is crucial.
- Void behavior under shear stress dictates material failure mechanisms.
- Defect formation is key to plastic deformation in glasses.
Purpose of the Study:
- To investigate the shear deformation and breakup mechanisms of voids in silica glass.
- To identify defect evolution during elastic and plastic deformation.
- To elucidate the nucleation and growth of nanocracks.
Main Methods:
- Molecular dynamics simulations were employed.
- Simulations tracked void evolution under increasing shear strain.
- Defect structures (threefold-coordinated silicon, nonbridging oxygen) were analyzed.
Main Results:
- Spherical voids deformed into ellipsoids with increasing shear strain.
- Threefold-coordinated silicon and nonbridging oxygen defects emerged during elastic deformation.
- Nanocracks nucleated on void surfaces for shear strains >15%, leading to plastic, threadlike deformation.
- Nanocracks formed via migration of defects on Si-O rings.
- Threadlike structures fragmented for shear strains >40%.
Conclusions:
- Shear deformation induces significant structural changes and defect generation in silica glass voids.
- The study reveals a distinct transition from elastic deformation to plastic flow and fragmentation.
- Defect dynamics are critical in the initiation and propagation of nanocracks and subsequent breakup.
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