Title: An efficient time-domain perfectly matched layers formulation for elastodynamics on spherical domains

Abstract

Many practical applications require the analysis of elastic wave propagation in a homogeneous isotropic media in an unbounded domain. One widely used approach for truncating the infinite domain is the so called method of perfectly matched layers (PMLs). Most existing PML formulations are developed for finite difference methods based on the first-order velocity-stress form of the elasticity equations, and they are not straight-forward to implement using standard finite element methods (FEMs) on unstructured meshes. Some of the problems with these formulations include the application of boundary conditions in half-space problems and in the treatment of edges and/or corners for time-domain problems. Several PML formulations, which do work with FEMs have been proposed, although most of them still have some of these problems and/or they require a large number of auxiliary nodal history/memory variables. Here in this work, we develop a new PML formulation for time-domain elastodynamics on a spherical domain, which reduces to a two-dimensional formulation under the assumption of axisymmetry. Our formulation is well-suited for implementation using FEMs, where it requires lower memory than existing formulations, and it allows for natural application of boundary conditions. We solve example problems on two-dimensional and three-dimensional domains using a high-order discontinuous Galerkinmore » (DG) discretization on unstructured meshes and explicit time-stepping. We also study an approach for stabilization of the discrete equations, and we show several practical applications for quality factor predictions of micromechanical resonators along with verifying the accuracy and versatility of our formulation.« less

Authors:

Sagiyama, K. ^[1]; Govindjee, S. ^[1]; Persson, P. -O. ^[1]

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+ Show Author Affiliations

1. Univ. of California, Berkeley, CA (United States). Dept. of Civil Engineering

Publication Date:

Tue Jul 15 00:00:00 EDT 2014

Research Org.:

Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)

Sponsoring Org.:

USDOE Office of Science (SC); National Science Foundation (NSF)

OSTI Identifier:

1523916

Grant/Contract Number:  

AC02-05CH11231; FA9550-10-1- 0229

Resource Type:

Accepted Manuscript

Journal Name:

International Journal for Numerical Methods in Engineering

Additional Journal Information:

Journal Volume: 100; Journal Issue: 6; Journal ID: ISSN 0029-5981

Publisher:

Wiley

Country of Publication:

United States

Language:

English

Subject:

42 ENGINEERING; PML; perfectly matched layer; elastodynamics; Discontinuous Galerkin; stabilization