Natural element analysis of the cahn-hilliard phase-field model amirtham rajagopal

Rajagopal, A., Fischer, P., Kuhl, E. and Steinmann, P. (2010) Natural element analysis of the cahn-hilliard phase-field model amirtham rajagopal. Computational Mechanics, 46(3-4), pp. 471-493. (doi: 10.1007/s00466-010-0490-4)

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Abstract

We present a natural element method to treat higher-order spatial derivatives in the Cahn–Hilliard equation. The Cahn–Hilliard equation is a fourth-order nonlinear partial differential equation that allows to model phase separation in binary mixtures. Standard classical C0 -continuous finite element solutions are not suitable because primal variational formulations of fourth-order operators are well-defined and integrable only if the finite element basis functions are piecewise smooth and globally C1 -continuous. To ensure C1 -continuity, we develop a natural-element-based spatial discretization scheme. The C1 -continuous natural element shape functions are achieved by a transformation of the classical Farin interpolant, which is basically obtained by embedding Sibsons natural element coordinates in a Bernstein–Bézier surface representation of a cubic simplex. For the temporal discretization, we apply the (second-order accurate) trapezoidal time integration scheme supplemented with an adaptively adjustable time step size. Numerical examples are presented to demonstrate the efficiency of the computational algorithm in two dimensions. Both periodic Dirichlet and homogeneous Neumann boundary conditions are applied. Also constant and degenerate mobilities are considered. We demonstrate that the use of C1 -continuous natural element shape functions enables the computation of topologically correct solutions on arbitrarily shaped domains.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Steinmann, Professor Paul
Authors: Rajagopal, A., Fischer, P., Kuhl, E., and Steinmann, P.
College/School:College of Science and Engineering > School of Engineering > Infrastructure and Environment
Journal Name:Computational Mechanics
Publisher:Springer
ISSN:0178-7675
ISSN (Online):1432-0924
Published Online:07 April 2010
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