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Photoelastic confirmation of surface stress relaxation in silica glasses: Fiber bending and rod torsion
Author(s) -
Hausmann Bronson D.,
Aaldenberg Emily M.,
Tomozawa Minoru
Publication year - 2021
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/jace.17690
Subject(s) - materials science , composite material , residual stress , torsion (gastropod) , stress relaxation , shear stress , surface stress , bending , glass fiber , photoelasticity , shear (geology) , relaxation (psychology) , creep , solid mechanics , medicine , psychology , social psychology , surgery , surface energy
Silica glass samples were given various heat treatments under stress at low temperatures and subsequently their residual stress distributions in terms of retardance were observed using a polarized light microscope, confirming previously reported fast surface stress relaxation while providing more detailed characterization. Retardance profiles of silica glass fibers heat‐treated under a constant bending strain in the presence of atmospheric water vapor were measured and fit to a previously developed diffusion‐based relaxation model. The retardance of a cross‐section of a silica glass rod heat‐treated at 650°C in lab air under applied torsional shear strain was also measured to confirm the presence of residual surface shear stress which was predicted by the decrease of torque with time for the rod. Together, these results confirm the low‐temperature fast surface stress relaxation which occurs when water vapor is present for both bending and shear stresses.