Detection of an evanescent scattered wave field by the dynamic shear strain and spatio-temporal gradient analysis

2014 Fiscal Year Final Research Report

• Project/Area Number: 22560421
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Measurement engineering
• Research Institution: Saga University
• Principal Investigator: TERAMOTO Kembu 佐賀大学, 工学(系)研究科(研究院), 教授 (70207489)
• Project Period (FY): 2010-04-01 – 2015-03-31
• Keywords: 非破壊検査 / 超音波計測 / 動的せん断歪み解析 / 超音波撮像 / 波動応用計測 / ガイド波

Outline of Final Research Achievements

A Quantitative acoustical imaging technology is used or developed to classify the region of defect. The proposed evanescent field imaging method can be summarized as follows. 1) The distributions of the normal displacement of the object surface is governed by the 2-dimensional wave equation in the Lamb-wave field. 2) When the single propagating wave front exists on the surface of the object with no defect, the orthogonal pair of the out-of-plane shear strains are linearly dependent each other. Therefore the determinant of a covariance matrix which is composed of the orthogonal pair of the shear strains becomes zero. 3) When a region of interest having somewhat inhomogeneity exists, scattered wave arises in the Lamb-wave field. Consequently, the determinant becomes larger than zero because of the independency between the orthogonal pair over the region of the scattered and incident wave field.

Free Research Field

計測工学