The Depth Limits of Eddy Current Testing for Defects: A Computational Investigation and Smooth-Shaped Defect Synthesis from Finite Element Optimization

Abstract

This paper presents a computational investigation of the validity of eddy current testing (ECT) for defects embedded in steel using parametrically designed defects. Of particular focus is the depths at which defects can be detected through ECT. Building on this we characterize interior defects by parametrically describing them and then examining the response fields through measurement. Thereby we seek to establish the depth and direction of detectable cracks. As a second step, we match measurements from eddy current excitations to computed fields through finite element optimization. This develops further our previously presented methods of defect characterization. Here rough contours of synthesized shapes are avoided by a novel scheme of averaging neighbor heights rather than using complex Bezier curves, constraints and such like. This avoids the jagged shapes corresponding to mathematically correct but unrealistic synthesized shapes in design and nondestructive evaluation.

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Document Details

Document Type
Technical Report
Publication Date
Apr 22, 2015
Accession Number
ADA626748

Entities

People

  • P. Jayakumar
  • R. Thyagarajan
  • S. R. Hoole
  • T. Mathialakan
  • V. U. Karthik

Organizations

  • Michigan State University

Tags

Communities of Interest

  • Ground and Sea Platforms

DTIC Thesaurus Topics

  • Algorithms
  • Computational Processes
  • Computations
  • Current Density
  • Eddy Currents
  • Engineering
  • Finite Element Analysis
  • Flux Density
  • Frequency
  • Genetic Algorithms
  • Graphics Processing Unit
  • Identification Systems
  • Magnetic Fields
  • Materials
  • Military Research
  • Optimization
  • Systems Engineering

Readers

  • Approximation Theory.
  • Metallurgy
  • Operations Research