Load-Differential Features for Automated Detection of Fatigue Cracks Using Guided Waves (Preprint)

Abstract

Guided wave structural health monitoring (SHM) is being used to assess the integrity of plate-like structures for aerospace, civil and mechanical applications. Prior research has investigated how guided wave propagation is affected by applied loads, which induce anisotropic changes in both dimensions and phase velocity. In addition, it is well-known that applied tensile loads open fatigue cracks and thus enhance their detectability using ultrasonic methods. Here we introduce a class of load-differential methods in which signals recorded from different loads at the same damage state are compared without using previously obtained damage-free data. Changes in delay-and-sum images are considered as a function of differential loads. Load-differential features are extracted from these images that capture the effects of loading as fatigue cracks are opened. Damage detection thresholds are adaptively set based upon the load-differential behavior of the various features, which enables implementation of an automated fatigue crack detection process.

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Document Details

Document Type
Technical Report
Publication Date
Nov 01, 2011
Accession Number
ADA553289

Entities

People

  • Jennifer E. Michaels
  • Sang J. Lee
  • Thomas E. Michaels
  • Xin Chen

Organizations

  • Georgia Tech Research Corporation

Tags

Communities of Interest

  • Biomedical
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Air Force
  • Air Force Research Laboratories
  • Calorific Value
  • Damage Detection
  • Data Sets
  • Detection
  • Engineering
  • Frequency
  • Group Velocity
  • Military Research
  • Monitoring
  • Phase Velocity
  • Structural Health Monitoring
  • Transducers
  • Two Dimensional
  • Wave Propagation
  • Waveform Generators

Fields of Study

  • Engineering

Readers

  • Computer Vision.
  • Structural Health Monitoring of Composite Structures.

Technology Areas

  • Space