Non-Newtonian viscous flow in glass

Simmons, Joseph H.; Mohr, R. K.; Montrose, C. J.

doi:10.1063/1.331272

Cited by 142 publications

(113 citation statements)

References 7 publications

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“…These experimental results indicate shear-thinning behavior with the viscosity decreasing with increasing strain rate while the stress continues to increase near the glass transition temperature of the material [Webb and Dingwell, 1990a;Simmons, 1998]. Such a feature of the steady-state viscosity is frequently represented by an empirical function of strain rate [Simmons et al, 1982;Simmons, 1998]. Bottinga [1994a] attributed the viscosity reduction to a change of configurational entropy due to accumulation of elastic energy in the material and represented the viscosity as a function of the elastic energy.…”

Section: Introductionmentioning

confidence: 99%

Brittleness of fracture in flowing magma

Ichihara

Rubin

2010

J. Geophys. Res.

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[1] Understanding the transition to brittle fracture of flowing magma is essential for estimating the explosiveness of a volcanic eruption. In order to quantify brittleness of flowing magma, a new parameter b is introduced, which is a function of the ratio of the rate of change of the strain energy due to elastic distortional deformation to the mechanical power due to total distortional deformation rate. From the perspective of b, dependence of brittle fracture of magma on stress, decompression rate, strain rate, and shear-thinning effects are reviewed. The experimental data of Kameda et al. (2008) for rapid decompression of simulants of bubbly magma have also been reexamined. The results show that b exhibits a strong transition that correlates well with the observed transition between ductile expansion to brittle fragmentation. Moreover, b is useful in considering the effects of shear-thinning and steady-creep conditions on brittle fracture. Statements in the literature that suggest that materials behave in a brittle manner at sufficiently high strain rate are correct. However, these statements do not precisely quantify the notion of high strain rate so they are easy to misinterpret when considering the effect of shear thinning. Although shear thinning tends to increase the absolute magnitude of the total strain rate, it does not necessarily increase brittleness. Also, in principle, it is unlikely for brittle fracture to occur at steady creep. Cracking observed in steady-creep experiments of magma (Lavallee et al., 2007 may be attributed to small fluctuations with sufficiently high frequencies to satisfy the conditions for brittle fracture.

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Section: Introductionmentioning

confidence: 99%

Brittleness of fracture in flowing magma

Ichihara

Rubin

2010

J. Geophys. Res.

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“…A complete understanding of magma rheology requires a comprehensive description of the rheology of the melt phase [Shaw, 1965], Most studies of shear viscosities of Silicate melts have been conducted at conditions of relatively high temperatures and low viscosities (see compilations by Bottinga and Weill [1972], Bansal and Doremus [1986], and Ryan and Blevins [1987]). In cases where the stress-strain rate relationship has been investigated over a significant ränge of strain rate, both Newtonian behavior (i.e., linear stress-strain rate relationship) [e.g., Scarfe et al, 1983] and non-Newtonian behavior [e.g., Li and Vhlmann, 1970;Simmons et al, 1982;Spera et al, 1982] have been observed. [1989] suggested that the strain rates above which non-Newtonian behavior is expected to occur in Silicate melts can be predicted from linear viscoelastic theory.…”

Section: Introductionmentioning

confidence: 99%

Non‐Newtonian rheology of igneous melts at high stresses and strain rates: Experimental results for rhyolite, andesite, basalt, and nephelinite

Webb¹,

Dingwell²

1990

J. Geophys. Res.

266

182

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The stress‐strain rate relationships of four silicate melt compositions (high‐silica rhyolite, andesite, tholeiitic basalt, and nephelinite) have been studied using the fiber elongation method. Measurements were conducted in a stress range of 10–400 MPa and a strain rate range of 10−6 to 10−3 s−1. The stress‐strain rate relationships for all the melts exhibit Newtonian behavior at low strain rates, but non‐Newtonian (nonlinear stress‐strain rate) behavior at higher strain rates, with strain rate increasing faster than the applied stress. The decrease in calculated shear viscosity with increasing strain rate precedes brittle failure of the fiber as the applied stress approaches the tensile strength of the melt. The decrease in viscosity observed at the high strain rates of the present study ranges from 0.25 to 2.54 log10 Pa s. The shear relaxation times τ of these melts have been estimated from the low strain rate, Newtonian, shear viscosity, using the Maxwell relationship τ = ηs/G∞. Non‐Newtonian shear viscosity is observed at strain rates ( trueε˙=time−1 ) equivalent to time scales that lie 3 log10 units of time above the calculated relaxation time. Brittle failure of the fibers occurs 2 log10 units of time above the relaxation time. This study illustrates that the occurrence of non‐Newtonian viscous flow in geological melts can be predicted to within a log10 unit of strain rate. High‐silica rhyolite melts involved in ash flow eruptions are expected to undergo a non‐Newtonian phase of deformation immediately prior to brittle failure.

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“…10. Similar decrease in viscosity with strain rate has been observed at high stress and high strain rate conditions in many kinds of amorphous and glassy materials such as oxide glass materials, 21,22) amorphous polymer materials, 23) metallic glass alloys, 24) while these materials usually exhibit Newtonian viscous flow at low stress and low strain rate conditions at relatively high temperatures. In case of polymer materials, such decrease in viscosity with strain rate is 23) It is however difficult for this Si-B-C-N ceramics to explain the decrease in viscosity by the entanglements of intermolecular chains, since the atomic configuration is not constituted of long molecular chains but is based on aperiodic connections of tetrahedral structure.…”

Section: Discussionmentioning

confidence: 63%

Compressive Deformation of Partially Crystallized Amorphous Si-B-C-N Ceramics at Elevated Temperatures

Ishihara¹,

Hirayama²,

Aldinger

et al. 2003

Mater. Trans.

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The deformation behavior of Si-B-C-N ceramics derived from a polymer precursor has been investigated by compression tests at high temperatures. The hot isostatic pressing of pyrolyzed powder compact was conducted at 1450 C and at 900 MPa in order to obtain a dense ceramic monolith. The material consisted of the amorphous matrix and the dispersed Si 3 N 4 particles with the diameter of about 20 nm. While only apparent elastic deformation was observed at the testing temperatures up to 1500 C, significant plastic deformation occurred at temperatures higher than 1650 C. The plastic deformation is considered to be caused by the viscous flow of the amorphous matrix. The flow stress at the testing temperatures in the range of 1650 to 1750 C increased with initial strain rate. The flow stress was not proportional to the strain rate. The shear viscosity at 0.02 strain was about 10 11 -10 13 Pa s and decreased proportionally to about À0:75 power of the strain rate. The decrease in shear viscosity is considered to show a strain localization behavior. Strain hardening was observed during the plastic deformation. As the reason of the strain hardening, the crystallization can be considered, in addition to the decrease in atomic site defects during the deformation.

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Non-Newtonian viscous flow in glass

Cited by 142 publications

References 7 publications

Brittleness of fracture in flowing magma

Brittleness of fracture in flowing magma

Non‐Newtonian rheology of igneous melts at high stresses and strain rates: Experimental results for rhyolite, andesite, basalt, and nephelinite

Compressive Deformation of Partially Crystallized Amorphous Si-B-C-N Ceramics at Elevated Temperatures

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