Electromagnetic NDE Methods

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Electromagnetic NDE Methods

• Shreekanth Mandayam
• Principles of Nondestructive Evaluation
• Graduate / Senior Elective
• 0909-504-01/0909-413-01
• Fall 1999

September 20, 1999
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Plan
9/20/99

• Electromagnetic NDE methods
• Problem statement
• Maxwells equations
• Governing equations
• Static
• Quasi-static
• Wave
• Selection of class projects
• Open discussion

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Problem Statement
Energy input, x F1(a, f)
Amplitude, a Frequency, f
Defect geometry, d
Coupling device, c
Measurement system, m
Specimen geometry, g Specimen material
distribution, p
Signal output, y F2(a, f, c, g, p, d, m)
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Maxwells Equations
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Constitutive Relationships
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Electromagnetic NDE Methods
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Static Phenomena DC Potential Drop
Elliptic partial differential equation
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Static Phenomena Magnetic Flux Leakage
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Static Phenomena MFL (contd.)
Elliptic partial differential equation
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Quasi-static Phenomena
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Quasi-static Phenomena
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Quasi-static Phenomena (contd.)
Parabolic partial differential equation
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Wave Phenomena
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Wave Phenomena (contd.)
Hyperbolic partial differential equation
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Reference

• William Lord, Partial differential equations and
  the NDE inverse problem, Review of Progress in
  Quantitative Nondestructive Evaluation, Vol. 7,
  pp. 425-430, 1988

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NDE Processes
Inverse Problem Difficulty
Forward Problem Difficulty
Informational Entropy
HIGH
LOW
HIGH
Elliptic Processes
Parabolic Processes
Hyperbolic Processes
LOW
LOW
HIGH
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Proposal Format

• Background
• Research Objective
• Proposed Methodology
• Deliverables
• Project timeline

Please come prepared to present a project
proposal for the next class meeting (Sep 27).