日本語フィールド
著者:寺本 顕武 田町 尚弘 読み: テラモトケンブ タマチナオヒロ題名:Near-field Acoustical Imaging of Cracks
over the A0-mode Lamb-wave Field発表情報:Proceedings of SICE2010 (in CDROM) ページ: Cキーワード:
non-destructive inspection; inverse problem; ultrasonic measurement; acoustical near-field imaging概要:抄録:The Use of Lamb waves has recently been interested in the
non-destructive evaluations for thin-plate-like structures.
The conventional time-of-flight technique is not
reliable for locating the defects even in isotropic plates
because of the dispersiveness in the Lamb wave propagation.
Avoiding difficulties caused by the dispersiveness,
this paper proposes a novel spatio-temporal gradient imaging method
which has an ability to localize cracks and to reconstruct
the near-field images of cracks.
The proposed imaging method utilizes
the determinant of covariance matrix of dynamic shear strains
which are defined
over the object surface. The determinant denotes the distribution of
correlated intensity modulation
of the incident wave fronts with scattered ones. The determinant
increases significantly in the near-field of the point-like defects.
In this study, the computational process in the wave field near the defects
is discussed and their physical meanings are investigated
through FDTD-simulations and acoustic experiments.英語フィールド
Author:Kenbu Teramoto, Nohiro TamachiTitle:Near-field Acoustical Imaging of Cracks
over the A0-mode Lamb-wave FieldAnnouncement information:Proceedings of SICE2010 (in CDROM) Page: CKeyword:
non-destructive inspection; inverse problem; ultrasonic measurement; acoustical near-field imagingAn abstract:The Use of Lamb waves has recently been interested in the
non-destructive evaluations for thin-plate-like structures.
The conventional time-of-flight technique is not
reliable for locating the defects even in isotropic plates
because of the dispersiveness in the Lamb wave propagation.
Avoiding difficulties caused by the dispersiveness,
this paper proposes a novel spatio-temporal gradient imaging method
which has an ability to localize cracks and to reconstruct
the near-field images of cracks.
The proposed imaging method utilizes
the determinant of covariance matrix of dynamic shear strains
which are defined
over the object surface. The determinant denotes the distribution of
correlated intensity modulation
of the incident wave fronts with scattered ones. The determinant
increases significantly in the near-field of the point-like defects.
In this study, the computational process in the wave field near the defects
is discussed and their physical meanings are investigated
through FDTD-simulations and acoustic experiments.