s. mandayam/ nde/ fall 99 principles of nondestructive evaluation shreekanth mandayam graduate /...
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S. Mandayam/ NDE/ Fall 99
Principles of Nondestructive Principles of Nondestructive EvaluationEvaluation
Shreekanth Mandayam
Graduate / Senior Elective0909-504-01/0909-413-01
Fall 1999http://engineering.rowan.edu/~shreek/fall99/nde/
Lecture 2Lecture 29/20/999/20/99
S. Mandayam/ NDE/ Fall 99
PlanPlan
• Electromagnetic NDE methods• Problem statement• Maxwell’s equations• Governing equations
• Static• Quasi-static• Wave
• Selection of class projects• Open discussion
9/20/99
S. Mandayam/ NDE/ Fall 99
Problem StatementProblem Statement
Amplitude, aFrequency, f
Coupling
device, c
Specimen geometry, gSpecimen material distribution, p
Defect geometry, d
Measurement
system, m
Energy input, x = F1(a, f)
Signal output, y = F2(a, f, c, g, p, d, m)
S. Mandayam/ NDE/ Fall 99
Electromagnetic NDE Electromagnetic NDE MethodsMethods
DC Potential DropM agnetic Flux Leakage
Static Phenom enaElliptic Equations
f = 0
Eddy Current
Q uasi-static Phenom enaParabolic Equations
f < 1 M Hz
M icrow ave
W ave Phenom enaHyperbolic Equations
f > 1 M Hz
NDE Phenom enaM axw ell's Equations
S. Mandayam/ NDE/ Fall 99
Static Phenomena: Static Phenomena: DC Potential DropDC Potential Drop
0
s,coordinatecartesian In
0 0)(
, Since
0 0
then,0 If
2
2
2
2
2
2
2
z
V
y
V
x
V
VV
VE
EE
D
v
v
Elliptic partial
differential equation
S. Mandayam/ NDE/ Fall 99
Static Phenomena: Static Phenomena: Magnetic Flux LeakageMagnetic Flux Leakage
01
,0 0,f Since
B
JHtDtD
JH
S. Mandayam/ NDE/ Fall 99
Static Phenomena: Static Phenomena: MFL (contd.)MFL (contd.)
Elliptic partial
differential equation
JA
JA
ABA
2
toreduces media, isotropicfor which,
1
potential vector magnetic: where, Since
S. Mandayam/ NDE/ Fall 99
Quasi-static PhenomenaQuasi-static Phenomena
JA
JH
JtD
tD
JH
1
sfrequencie low""At
S. Mandayam/ NDE/ Fall 99
Quasi-static Phenomena (contd.)Quasi-static Phenomena (contd.)
tA
A
tA
A
tA
VA
EA
E
c2
c
J
or,
J1
1
1
J Since
Parabolic partial
differential equation
S. Mandayam/ NDE/ Fall 99
Wave PhenomenaWave Phenomena
tD
JjE
HjE
HjE
eEEeBB tjtj
)(
)()(
;
fields, harmonic-imeConsider t
00
S. Mandayam/ NDE/ Fall 99
Wave Phenomena (contd.)Wave Phenomena (contd.)
0
)(
Also,
,0 region, free-source aIn
22
2
EE
EE
EjtD
J
Hyperbolic partial
differential equation
S. Mandayam/ NDE/ Fall 99
ReferenceReference
• William Lord, “Partial differential equations and the NDE inverse problem,” Review of Progress in Quantitative Nondestructive Evaluation, Vol. 7, pp. 425-430, 1988
S. Mandayam/ NDE/ Fall 99
NDE ProcessesNDE Processes
Elliptic Processes
Parabolic Processes
Hyperbolic Processes
HIGHHIGHLOW
LOWLOWHIGH
ForwardProblemDifficulty
InverseProblemDifficulty
InformationalEntropy
S. Mandayam/ NDE/ Fall 99
Class ProjectsClass Projects
1. Ultrasound NDE: Neural nets for signal interpretation
2. Ultrasound NDE: Invariant signal recognition
3. Eddy current NDE: Simulating eddy current inspection of VLSI chips (proposal to NSF)
S. Mandayam/ NDE/ Fall 99
Class ProjectsClass Projects
4. Eddy current NDE: Design and develop an eddy current instrument (measure amplitude and phase of voltage using commercial eddy current probes)
5. Microwave NDE: System set up and experimentation for detecting frayed insulation in aircraft wiring
S. Mandayam/ NDE/ Fall 99
Class ProjectsClass Projects
6. Thermal NDE: Set up system to perform thermal imaging
7. Parallel Processing & Monte Carlo Modeling: Develop software for solving NDE forward problems using Monte Carlo techniques
8. Magnetic Flux Leakage NDE: Neural networks for invariant recognition
S. Mandayam/ NDE/ Fall 99
Class ProjectsClass Projects
9.--- Student specified projects: Check with instructor