Recent advances in computational methods for microsystems
Alberto Corigliano
1,a
, Martino Dossi
1,b
and Stefano Mariani
1,c
1
Department of Civil and Environmental Engineering, Politecnico di Milano
Piazza L. da Vinci 32, 20133 Milano, Italy
a
alberto.corigliano@polimi.it,
b
dossi@stru.polimi.it,
c
stefano.mariani@polimi.it
Keywords: MEMS; Electro-mechanical problem; Finite element method; Domain decomposition;
Proper orthogonal decomposition.
Abstract. An algorithm, which combines the use of Domain Decomposition and Model Order
Reduction methods based on Proper Orthogonal Decomposition, is proposed. The algorithm allows
for the efficient handling of electro-mechanical coupled problems in MEMS, with a strong
reduction of computing time with respect to standard monolithic or staggered solution strategies.
Examples of coupled electro-mechanical problems, concerning a vibrating beam subject to variable
electrostatic forces, are presented and discussed.
Introduction
Microsystems, or Micro Electro Mechanical Systems (MEMS), (see e.g. [1]) are complex
devices in which the design phase strongly depends on modeling and simulations. Due to the
combination of multi-physics and multi-scale problems in MEMS, the computational burden can
become extremely high or prohibitive for realistic models. The attempt to find efficient techniques
for the simulation of complex problems in MEMS has fostered research in many directions. One of
these directions, also explored in the present paper, is the use of Domain Decomposition (DD)
and/or Model Order Reduction (MOR) methods to drastically reduce the computing time and to
efficiently exploit possibilities offered by large scale and parallel computing. Recent attempts to
combine the use of DD and MOR techniques in various contexts can be found e.g. in [2,3,4].
The goal of this paper is to show how the combination of a DD technique with a reduced order
model obtained with the Proper Orthogonal Decomposition (POD) [5,6] can give rise to an
algorithm which efficiently solves the electro-mechanical coupled problem [7,8,9], which is one of
the typical ones for MEMS found e.g. in capacitive sensors or actuators.
The proposed approach is part of a wider research activity which aims at obtaining realistic
modeling and simulation techniques with computing times compatible with the design phases.
Starting from the DD techniques formulated in [10,11] for structural dynamics, the Authors already
proposed in [12] an original DD approach for the solution of the coupled electro-mechanical
problem. Subsequently, the Authors proposed in [13] a combination of DD and POD conceived for
the solution of coupled problems in MEMS. The present paper contains a further advancement with
respect to [13], which consists in a different way to impose continuity between the initially de-
coupled domains and in various strategies for the application of POD to the mechanical part of the
solution domain. The proposed technique is one step further in the formulation of a general DD-
POD approach which allows for the simulation of highly non-linear coupled problems, in the
presence of irreversible material behaviors like e.g. plasticity and fracture.
The paper is organized as follows: the electro-mechanical coupled problem is first formulated,
together with its semi-discretized version; subsequently the DD, the POD techniques and the way in
which they are here coupled are briefly discussed; numerical results concerning a vibrating beam
under the action of variable electrostatic forces are discussed; final remarks conclude the paper.
Formulation of the electro-mechanical problem
With reference to Fig. 1, we focus on a two-dimensional domain Ω composed by an electrical
part Ω
and a mechanical part Ω
, separated by the interface Γ. The outer boundary of Ω is divided
Advanced Materials Research Vol. 745 (2013) pp 13-25
© (2013) Trans Tech Publications, Switzerland
doi:10.4028/www.scientific.net/AMR.745.13
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