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| Titel |
Fracture and healing cycles in glass |
| VerfasserIn |
Yan Lavallée, Fabian Wadsworth, Jeremie Vasseur, Jackie Kendrick, Felix von Aulock |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098882
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| Publikation (Nr.) |
 EGU/EGU2014-14600.pdf |
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| Zusammenfassung |
| The repeated occurrence of fracture and healing occurs in a variety of geological,
biological, metallurgical and engineering processes. In geology, it is most common in
active tectonic regions, earthquake settings and volcanic conduits, where healing
is thought to be intrinsically related to diffusional processes, aided by catalytic
fluids.
In this study, cycles of compression, healing by contact and tension are performed on
standard soda-lime silicate liquids at high temperatures (500 to 700 °C; i.e., in the diffusive
regime of the viscoelastic body). The flat ends of two cylinders are brought in contact at
relatively low strain rates (10-3 s-1) until a target normal stress is reached (1, 2.5, 5 and 10
MPa). The specimens are then held in contact whilst the normal stress is left to
viscously dissipate for a different portion of Maxwell’s relaxation timescale for the
liquid (0.25, 0.5, 1, 2.5, 5, 10, 20, 40, 80, 160, 320) in order to achieve different
degrees of fracture healing. Strength recovery is assessed by subjecting the healed
sample to a rapid tension event at 10-1 s-1 (to ensure a purely brittle response). We
note that healing becomes efficient when allowed to operate for at least 5 times the
relaxation timescale of the material. From this point onward, we observe an exponential
increase in strength as a function of healing time. A small component of heat is
generated during failure, monitored using a high-speed infrared thermographic
camera.
We find that fracture-healing dynamics has similarities with sintering, whereby the
kinetics of the process is viscosity and diffusion dependent. Here we aim to expand this
definition with normal applied stress constraints and link fracture and healing cycles to
seismic swarms. Seismicity is perceived as a first order constraint on the mechanics of
magma ascent and facilitates assessment of the real-time rheological state of magma in
conduits. The processes presented here may be equally applicable to the strength
recovery of tectonic fractures/ faults harbouring frictional melt (i.e., pseudotachylytes). |
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