Spatio-Temporal Gradient Analysis for Detecting Defects

• TERAMOTO Kenbu

  Department of Mechanical Engineering, Saga University

• TSURUTA Kohsuke

  Department of Advanced Systems Control Engineering, Saga University

Abstract

This paper provides a novel signal processing for detecting defects based on the spatio-temporal gradient analysis over the Lambwave field. The proposed processing classifies the wave field through the rank of the covariance matrix which is defined by the four-dimensional vector with following components : a vertical displacement, its vertical velocity, and a pair of out-of-plane shearing strains. The covariance matrix provides the information about defects. Its determinant, therefore, is proposed as the inhomogeneity-index of the object surface. In this study, the physical meanings of the proposed index are shown, the computational process in the Lamb-wave field near the defects is discussed and their behaviors are investigated through FDTD-simulations and acoustic experiments.

Journal

• IEICE Trans. Fundamentals, A

  IEICE Trans. Fundamentals, A 87 (8), 2037-2044, 2004-08-01

  The Institute of Electronics, Information and Communication Engineers

Keywords

• spatio-temporal gradient analysis
• array signal processing
• lamb-wave
• non-destructive testing

Details

• CRID: 1571698602418844800
• NII Article ID: 110003213135
• NII Book ID: AA10826239
• ISSN: 09168508
• Text Lang: en
• Data Source:
  • CiNii Articles