Elastic-wave identification of penetrable obstacles using shape-material sensitivity framework

JOURNAL OF COMPUTATIONAL PHYSICS

卷:228

Article

Bonnet, Marc¹  Guzina, Bojan B.² 

[1] Ecole Polytech, Solid Mech Lab UMR CNRS 7649, F-91128 Palaiseau, France

[2] Univ Minnesota, Dept Civil Engn, Minneapolis, MN 55455 USA

关键词: Shape-material sensitivity;    Elastodynamics;    Identification;    Inclusion;    Boundary element method;    Constrained optimization;   

DOI  :  10.1016/j.jcp.2008.09.009

来源: Elsevier

【 摘 要 】

This study deals with elastic-wave identification of discrete heterogeneities (inclusions) in an otherwise homogeneous reference solid from limited-aperture waveform measurements taken on its surface. On adopting the boundary integral equation (BIE) framework for elastodynamic scattering, the inverse query is cast as a minimization problem involving experimental observations and their simulations for a trial inclusion that is defined through its boundary, elastic moduli, and mass density. For an optimal performance of the gradient-based search methods suited to solve the problem, explicit expressions for the shape (i.e. boundary) and material sensitivities of the misfit functional are obtained via the adjoint field approach and direct differentiation of the governing BIEs. Making use of the message-passing interface, the proposed sensitivity formulas are implemented in a data-parallel code and integrated into a nonlinear optimization framework based on the direct BIE method and an augmented Lagrangian whose inequality constraints are employed to avoid solving forward scattering problems for physically inadmissible (or overly distorted) trial inclusion configurations. Numerical results for the reconstruction of an ellipsoidal defect in a semi-infinite solid show the effectiveness of the proposed shape-material sensitivity formulation, which constitutes an essential computational component of the defect identification algorithm. (C) 2008 Elsevier Inc. All rights reserved.

【 授权许可】

Free