Eddy Current Flows Around Cracks in Thin Plates for Nondestructive Testing

Abstract

The boundary element method is used to calculate the induced electric current flow around cracks in thin conducting plates. A low frequency approximation leads to a Poisson equation for the current density potential or stream function. A kernel is used which produces the correct singularity at the crack tip. The boundary condition on the crack, derived from Faraday's law, requires the line integral of the current density around the crack to be zero. Numerical results for induced currents due to a circular induction coil are given. These results show that hot spots, due to Joule heating, can occur at the tips of the crack. Comparison of numerical results with infrared scanning experiments of eddy currents in a cracked plate are given. It is hoped that the numerical method presented here will provide a tool to simulate both new and conventional nondestructive eddy current testing techniques.

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Document Details

Document Type
Technical Report
Publication Date
Mar 01, 1981
Accession Number
ADA104407

Entities

People

  • Francis C. Moon
  • M. A. Morjaria
  • S. Mukherjee

Organizations

  • Cornell University College of Engineering

Tags

Communities of Interest

  • Air Platforms
  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Boundary Element Methods
  • Crack Tips
  • Current Density
  • Differential Equations
  • Eddy Currents
  • Electric Current
  • Equations
  • Gaussian Quadrature
  • Hot Spots
  • Infrared Scanning
  • Integral Equations
  • Magnetic Fields
  • Mechanics
  • Nondestructive Testing
  • Plastic Explosives
  • Structural Engineering
  • Voltage

Readers

  • Fluid Dynamics.
  • Materials Science (Mechanical Engineering).
  • Plasma Physics.