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Assessment of phenomenological models for viscosity of liquids based on nonequilibrium atomistic simulations of copper

Xu, Peng and Çağin, Tahir and Goddard, William A., III (2005) Assessment of phenomenological models for viscosity of liquids based on nonequilibrium atomistic simulations of copper. Journal of Chemical Physics, 123 (10). Art. No. 104506. ISSN 0021-9606. http://resolver.caltech.edu/CaltechAUTHORS:XUPjcp05

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Abstract

The shear viscosity of liquid copper is studied using nonequilibrium molecular-dynamics simulations under planar shear flow conditions. We examined variation of viscosity as function of shear rate at a range of pressures (ca. 0 - 40 GPa). We analyzed these results using eight different phenomenological models and find that the observed non-Newtonian behavior is best described by the Powell-Eyring (PE) model: eta(gamma)=(eta(0)-eta(infinity))sinh(-1)(tau gamma)/(tau gamma)+eta(infinity), where gamma is the shear rate. Here eta(0) (the zero-shear-rate viscosity) extracted from the PE fit is in excellent agreement with available experimental data. The relaxation time tau from the PE fit describes the shear response to an applied stress. This provides the framework for interpreting the shear flow phenomena in complex systems, such as liquid metal and amorphous metal alloys.


Item Type:Article
Additional Information:Copyright © 2005 American Institute of Physics. Received 23 July 2004; accepted 2 February 2005; published online 13 September 2005. We thank Professor Bill Johnson for many useful discussions. This research was funded by the DARPA ARO-SAM program (Leo Christodoulou and Bill Mullins) and by the NSF-MRSEC (Center for the Science and Engineering Materials, CSEM). The facilities of the Materials and Process Simulation Center are also supported by the Department of Energy in addition to the National Science Foundation, ARO-MURI, MURI-ONR, General Motors, Chevron Texaco, Seiko-Epson, Nissan Corp., and the Beckman Institute.
Subject Keywords:molecular dynamics method; liquid metals; copper; viscosity; shear flow; non-Newtonian flow
Record Number:CaltechAUTHORS:XUPjcp05
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:XUPjcp05
Alternative URL:http://dx.doi.org/10.1063/1.1881052
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2623
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:13 Apr 2006
Last Modified:26 Dec 2012 08:50

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