ASM Metals HandBook Vol. 17 - Nondestructive Evaluation and Quality Control

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Engineers, 1970, p 484-487

16. B. Ostrofsky and N.B. Heckler, Detection of Creep Rupture in Ammonia Plant Reformer Headers,

Materials Engineering and Sciences Division Biennial Conference,

American Institute of Chemical

Engineers, 1970, p 472-476

17. R.R. Dalton, Ultrasonic Inspection of Cast HK-40 Tubes for Creep Fissures, Mater. Eval.,

Vol 32 (No.

12), Dec 1974, p 264-268

18. A.J. Willets, F.V. Ammirato, and J.A. Jones, Objectives and Techniques for Performance of In-

Service

Examination of Reactor Pressure Vessels, in

Performance and Evaluation of Light Water Reactor

Pressure Vessels, American Society of Mechanical Engineers, 1987, p 79-86

19. G.J. Dav and M.M. Behravesh, U.S. Developments in the Ultrasonic Examination of Pressure Vessels,

Int.

J. Pressure Vessels Piping, Vol 28, 1987, p 3-17

20. P.C. Riccardella, J.F. Copeland, and J. Gilman, Evaluation of Flaws or Ser

vice Induced Cracks in Pressure

Vessels, in Performance and Evaluation at Light Water Reactor Pressure Vessels,

American Society of

Mechanical Engineers, 1987, p 87-94

Nondestructive Inspection of Boilers and Pressure Vessels

Selected References

Replication Microscopy

•

J.J. Balaschak and B.M. Strauss, Field Metallography in Assessment of Steam Piping in Older Fossil

Power Plants, in Microstructural Science, Vol 15, ASM INTERNATIONAL, 1987, p 27-36

• C.J. Bolton, B.F. Dyson, and K.R. Williams, Metallogr

aphic Methods of Determining Residual Creep

Life, Mater. Sci. Eng., Vol 46, 1980, p 231-239

•

P.B. Ludwigsen, The Replica Method for Inspection of Material Structures and Crack Detection,

Structure, No. 15, Sept 1987, p 3-5

• B. Neubauer and U. Wedel, ND

T: Replication Avoids Unnecessary Replacement of Power Plant

Components, Power Eng., Vol 88 (No. 5), May 1984, p 5

•

N. Nilsvang and G. Eggeler, A Quantitative Metallographic Study of Creep Cavitation in a 12%

Chromium Ferritic Steel (X20 CrMoV 12 1), Pract. Metallogr., Vol 24, 1987, p 323-335

• E.V. Sullivan, Field Metallography Equipment and Techniques, in Microstructural Science,

Vol 15,

ASM INTERNATIONAL, 1987, p 3-11

Quantitative NDE (1980)

• A.J. Boland et al., "Development of Ultrasonic Tomography for Residual Stress Mapping," EPRI NP-

1407, Electric Power Research Institute, May 1980

• A.E. Holt, "Defect Characterization by Acoustic Holography--

Volume 1: Imaging in Field

Environments," EPRI NP-1534, Electric Power Research Institute, Sept 1980

• P.H. Hutton, "Development of an Acoustic Emission Zone Monitor and Recorder for BWR Pipe-

Cracking Detection," EPRI NP-1408, Electric Power Research Institute, June 1980

• W. Lord, "Magnetic Flux Leakage for Measurement of Crevice Gap Clearance and Tub

e Support Plate

Inspection," EPRI NP-1427, Electric Power Research Institute, June 1980

• W. Lord and R. Palanisamy, Magnetic Probe Inspection of Steam Generator Tubing, Mater. Eval.,

Vol 38

(No. 5), May 1980

• V.I. Neeley et al., "Technology Transfer Ph

ase of Advanced Ultrasonic Nuclear Reactor Pressure Vessel

Inspection System," EPRI NP-1535, Electric Power Research Institute, Sept 1980

•

G.P. Singh and J.L. Rose, "Ultrasonic Field Analysis Program for Transducer Design in the Nuclear

Industry," EPRI NP-1335, Electric Power Research Institute, Feb 1980

• S. Wenk et al., "NDE Characteristics of Pipe Weld Defects," EPRI NP-1590-

SR, Electric Power

Research Institute, Sept 1980

Quantitative NDE (1981)

• D.G. Eitzen et al., "Fundamental Development for

Quantitative Acoustic Emission Measurements," EPRI

NP-2089, Electric Power Research Institute, Oct 1981

• D.G. Eitzen et al.,

"Summary of Fundamental Development for Quantitative Acoustic Emission

Measurements," EPRI NP-1877, Electric Power Research Institute, June 1981

• T.D. Jamison et al., "Studies of Section XI Ultrasonic Repeatability," EPRI NP-

1858, Electric Power

Research Institute, May 1981

• W. Lord, "Development of a Finite Element Model for Eddy-Current NDT Phenomena," EPRI NP-

2026,

Electric Power Research Institute, Sept 1981

• W.R. McDearman et al., "Steam Generator Support Plate Radiography," EPRI NP-

2042, Electric Power

Research Institute, Sept 1981

• E.J. Parent et al., "Profilometry for Steam Generator Tube Dents," EPRI NP-2141, Electr

ic Power

Research Institute, Nov 1981

•

C.O. Ruud, "Review and Evaluation of Nondestructive Methods for Residual Stress Measurements,"

EPRI NP-1971, Electric Power Research Institute, Sept 1981

Quantitative NDE (1982)

• S. Brown, "Field Experiences With Multifrequency-

Multiparameter Eddy Current Technology," EPRI

NP-2299, Electric Power Research Institute, March 1982

• W.E. Cramer et al., "Application of an Eddy Current Technique to Steam Generator U-

Bend

Characterization," EPRI NP-2339, Electric Power Research Institute, April 1982

• G.J. Dau et al., Automatic Analysis of Eddy Current Signals, in

Proceedings of the 5th International

Conference on Inspection of Pressurized Components, Institute of Mechanical Engineers, 1982

• E.S. Furgason and V.L. Newhouse, "Evaluation of Pulse-Echo Ultrasound for Steam Generator Tube-to-

Support Plate Gap Measurement," EPRI NP-2285, Electric Power Research Institute, June 1982

• M.E. Lapides, Factors Influencing Detection, Location, and Sizing of Flaws: Intergranul

ar Stress

Corrosion Cracking (IGSCC), in

Proceedings of the 5th International Conference on Inspection of

Pressurized Components, Institute of Mechanical Engineers, 1982

• M.E. Lapides and T.U. Marston, In-Service Inspection of Heavy Section Castings: Tec

hniques, Results,

Implication, in Proceedings of the Seminar on Improvements in Power Plant Casting Quality

(St. Charles,

IL), American Society for Metals, 1982

• J.L. Rose et al., "A Physically Modelled Feature Based Ultrasonic System for IGSCC Classific

ation,"

Paper presented at the ASNT Spring Conference (Boston), American Society for Nondestructive Testing,

March 1982

Quantitative NDE (1983)

• C. Bradshaw, Benefits of Automatic Steam Generator Tube Inspection Data Acquisition, in

Proceedings

of the SMIRT-7 Post Conference (Monterey, CA), 1983

• S.D. Brown, "Eddy Current NDE for Intergranular Attack," EPRI NP-

2862, Electric Power Research

Institute, Feb 1983

• S.D. Brown, "Steam Generator U-Bend Eddy Current NDE," EPRI NP-3010, Electric Power Rese

arch

Institute, April 1983

•

M.E. Lapides, "Radiographic Detection of Intergranular Stress Corrosion Cracking: Analysis,

Qualification, and Field Testing," EPRI NP-3164-SR, Electric Power Research Institute, Oct 1983

• W. Lord, "Magnetic Flux Leakage for

Measurement of Crevice Gap Clearance and Tube Support Plate

Inspection," EPRI NP-2857, Electric Power Research Institute, Feb 1983

• W.R. McDearman et al., "Steam Generator Support Plate Radiographic Evaluation System," EPRI NP-

3253, Electric Power Research Institute, Jan 1983

• V.I. Neeley, "Development of a Production Prototype Pressure Vessel Imaging System," EPRI NP-

3253,

Electric Power Research Institute, Oct 1983

• R.B. Thompson et al., "A Prototype EMAT System for Inspection of Steam Generator Tubes," EPRI NP-

2836, Electric Power Research Institute, Jan 1983

Quantitative NDE (1984)

• F.L. Becker, Effective Demonstrations for Under Clad Crack Detection, in Non-

Destructive Examination

for Pressurised Components,

Elsevier, 1984

• R.L. Beverly a

nd R.A. Baker, "Evaluation of Nondestructive Examinations of Intergranular Stress

Corrosion Cracking Countermeasures," EPRI NP-3324-LD, Electric Power Research Institute, March 1984

• C.L. Bradshaw, Automatic Denting Analysis of Steam Generator Tubing, in Non-

Destructive Examination

for Pressurised Components,

Elsevier, 1984

• G.J. Dau and M.M. Behravesh, Status of Intergranular Stress Corrosion Crack Depth Sizing, in Non-

Destructive Examination for Pressurised Components, Elsevier, 1984

• M.E. Lapides, The Challenge of Continuous Flaw Monitoring in Electric Utilities Practice,

J. Pressure

Vessel Technol., Vol 106, Aug 1984

•

M.E. Lapides, MINAC: Portable, High Energy Radiographic Source; Experience and Applications, in

Non-Destructive Examination for Pressurised Components, Elsevier, 1984

• M.E. Lapides, Radiographic Detection of Crack-Like Defects in Thick Sections, Mater. Eval.,

Vol 42 (No.

6), May 1984

• C.R. Mikesell and S.N. Liu et al., Detection of Intergranular Stress Corrosion Cracking Using Au

tomated

Ultrasonic Techniques, in

Proceedings of the Nondestructive Testing and Electrochemical Methods of

Monitoring Corrosion in Industrial Plants, ATME E-7/G-1 Symposium, Montreal, Canada, May 1984

Quantitative NDE (1985)

• M.L. Fleming, Inspection of Pipe, Tubing and Plate, in Proceedings of the 1985 ASNT Spring Conference

(Washington, D.C.), American Society for Nondestructive Testing, 1985

• M.L. Fleming, Field Experience in Automated Ultrasonic Inspection of Stainless Steel, in

Proceedings of

the 1985 Pressure Vessels and Piping Conference

(New Orleans, LA), American Society of Mechanical

Engineers, 1985

• V.I. Neeley, "Application of Medical Ultrasonic Testing Technology to the Utility Industry," EPRI NP-

4034, Electric Power Research Institute, May 1985

• R.B. Thompson et al.,

"Ultrasonic Scattering From Intergranular Stress Corrosion Cracks: Derivation and

Application of Theory," EPRI NP-3822, Electric Power Research Institute, Jan 1985

Quantitative NDE (1986)

• F.V. Ammirato et al., "Development of Improved Procedure for Examination of Dissimilar-

Metal Welds in

BWR Nozzle-to-Safe-End Welds," EPRI NP-4606-LD, Electric Power Research Institute, May 1986

• M.J. Avioli, Jr., Modeling Ultrasonic Flaw Detection, EPRI J., Sept 1986

• F.L. Becker et al., NDT of Steam Piping and Headers, in

Proceedings of the Fossil Plant Inspections

Workshop, Electric Power Research Institute, 1986

• E.S. Furgason et al., "Digital Techniques to Improve Flaw Detection by Ultrasound Systems," EPRI NP-

4878, Electric Power Research Institute, Oct 1986

•

B.P. Hildebrand, "Investigation of Advanced Acoustic and Optical Nondestructive Evaluation Techniques,"

EPRI NP-4897, Electric Power Research Institute, Oct 1986

• K. Krzywosz, Trends and Recent Developments in NDE of Steam Generator Tubes, in

Proceedings of the

Fifth Annual Steam Generator NDE Workshop

(Myrtle Beach, SC), Steam Generator Owners Group II,

1986

• S.M. Walker, Ultrasonic Examination of Corrosion-Resistant Clad Weldments, in

Proceedings of the

Southwest Research Institute 14th Nuclear Power Educational Seminar,

Southwest Research Institute,

1986

• A.J. Willetts et al.,

"Evaluation of the Ultrasonic Data Recording and Processing System (UDRPS)," EPRI

NP-4397, Electric Power Research Institute, Jan 1986

Quantitative NDE (1987)

• F. Ammirato and S. Walker et al., Examination of Dissimilar Metal Welds in BWR Nozzle-to-Safe-

End

Joints, in Proceedings of the 8th International Conference on NDE in the Nuclear Industry

(Orlando, FL),

ASM INTERNATIONAL, 1987

• L. Becker and S. Walker et al., NDE of Fossil Plant Steam Piping, in

Proceedings of the 8th International

Conference on NDE in the Nuclear Industry (Orlando, FL), ASM INTERNATIONAL, 1987

• M.M. Behravesh et al., Status of Advanced UT Systems for the Nuclear Industry, Nucl. Eng. Des.,

No. 102,

1987, p 265-273

• D. Kedem, "Computed Tomography for Thick Steel Pipe and Castings," EPRI NP-5107-

LD, Electric Power

Research Institute, March 1987

• K. Krzywosz, Recent NDE Experience With PWR Steam Generator Tubing Inspection, in

Proceedings of

the 8th International Conference on NDE in the Nuclear Industry

(Orlando, FL), ASM INTERNATIONAL,

1987

•

D. MacDonald and E.K. Kietzman, Comparative Evaluation of Acoustic Holography Systems, in

Proceedings of the 8th International Conference on NDE in the Nuclear Industry

(Orlando, FL), ASM

INTERNATIONAL, 1987

•

D. MacDonald and S.M. Walker, "Effects of Ultrasonic Equipment Variations on Crack Length

Measurements," EPRI NP-5485, Electric Power Research Institute, Oct 1987

• G. Selby, "Ultrasonic Examination of BWR Replacement Pipe Joint MockUps," EPRI NP-5438-

LD,

Electric Power Research Institute, Aug 1987

• R.B. Thompson et al., "Modeling Ultrasonic Inspection of Nuclear Components--

Beam Models and

Applications," EPRI NP-5330, Electric Power Research Institute, Aug 1987

• A.J. Willetts and E.K. Kietzman, UT Techniques for Detection and Sizing of Under-

Clad Cracks in Reactor

Pressure Vessels, in Proceedings of the 8th International Conference on NDE in the Nuclear Industry

(Orlando, FL), ASM INTERNATIONAL, 1987

Quantitative NDE (1988)

•

F. Ammirato, "NDE of Cast Piping in the Nuclear Industry," Paper presented at the IAEA Specialists

Meeting on the Inspection of Austenitic and Dissimilar Metal Welds, Espoo, Fin

land, International Atomic

Energy Agency, June 1988

• F. Ammirato et al., Ultrasonic Examination of Dissimilar-Metal Welds in PWR and BWR Plants, in Non-

Destructive Examination in Relation to Structural Integrity, Proceedings of the Post-SMiRT Seminar #3,

Elsevier, 1988

• L. Goldberg, "Reliability of Magnetic Particle Inspection Performed Through Coatings," EPRI NP-

5919,

Electric Power Research Institute, July 1988

• J.D. Heald, "Evaluation of a New Gamma-Scanning Method for Detection and Sizing of Inter

granular

Stress Corrosion Cracking," EPRI NP-5759-LD, Electric Power Research Institute, May 1988

• B.P. Hildebrand, "Stepped Frequency Imaging for Flaw Monitoring," EPRI NP-

6033, Electric Power

Research Institute, Sept 1988

• B.P. Newberry and R.B. Thompson, Prediction of Surface Induced Ultrasonic Beam Distortions, in

Review

of Progress in Quantitative NDE-8, Plenum Press, 1988

• J.L. Rose, "Wave-

Propagation Studies for Improved Ultrasonic Testing of Centrifugally Cast Stainless

Steel," EPRI NP-5979, Electric Power Research Institute, Aug 1988

•

J. Saniee, T. Wong, and N.M. Bilgutay, Optimal Ultrasonic Flaw Detection Using a Frequency Diversity

Technique, in Review of Progress in Quantitative NDE-8, Plenum Press, 1988

• T. Sasahara and F. Ammirato, "Automated Ultrasonic Pipe Examination and Interpretation," EPRI NP-

5760, Electric Power Research Institute, April 1988

• R. Shankar, Field Application of Integrated Ultrasonic Feature-Based and Imaging-

Based Analysis, in

Proceedings of the 9th International Conference on Non-Destructive Evaluation in the Nuclear Industry,

ASM INTERNATIONAL, 1988

• R. Shankar et al., Feature-Enhanced Ultrasonic Imaging--

Application of Signal Processing and Analysis, in

Non-Destructive Examination in Relation to Structural Integrity, Proceedings of the Post-

SMiRT Seminar

#3, Elsevier, 1988

Introduction to Quantitative Nondestructive Evaluation

Vicki E. Panhuise, Allied-Signal Aerospace Company, Garrett Engine Division

Introduction

THE RELIABILITY of a nondestructive inspection (NDI) procedure was defined in the article "Reliability of Flaw

Detection by Nondestructive Inspection" in Volume 11 of the 8th Edition of Metals Handbook as a quantitative measure

of the efficiency of that procedure in finding flaws of specific type and size. During the years since that article was

published, many inspection reliability programs have been conducted, and various quantitative measurements have been

cited to express the procedure capabilities. To establish the basis for NDI method reliability, it is necessary to review the

history of NDI and its relation to reliability methods.

Historical Development of Quantitative Measurement Techniques

Nondestructive inspection methods are specified for material and/or component inspection requirements to maintain the

necessary quality for the final service life of the material/component. In most industries, the inspection requirements are

defined in a specification that describes the sensitivity level of the inspection method as well as the rejectable flaw size.

An example of a specification requirement is given in Table 1; the specification is based on longitudinal wave inspection

using flat-bottom holes (FBH). It defines the ultrasonic inspection requirements for product over 13 mm (0.5 in.) thick.

Table 1 indicates the defect detection/rejection limits for each quality class material. For example, quality class AA

requires that single discontinuities be detected at a sensitivity level equivalent to a No. 3 (1.2 mm, or in., diam) FBH.

In addition, multiple discontinuities

shall be detected at a sensitivity level equivalent to a No. 1 (0.4 mm, or in., diam)

FBH.

Table 1 Typical NDI acceptance criteria

Five classes of ultrasonic quality are establ

ished for longitudinal wave inspection. These classes are defined for inspection involving

flat-bottom reflectors in ultrasonic references.

Quality class

Single discontinuity

(a)

FBH No.

Multiple discontinuities

(a)

FBH No.

Maximum linear

discontinuity, in.

Maximum

loss of back

reflection, %

AA 3 1

(b)

No. 1 response for 0.12

A1 3 2

(c)

No. 2 response for 1.00

A 5 3 No. 3 response for 1.00

B 8 5 No. 5 response for 1.00

C As established by purchaser and vendor for specific part

Source: Ref 1

(a)

FBH numbers indicate diameter in multiples of 0.4 mm ( in.) of FBH in ultrasonic reference.

(b)

11% of a No. 3 FBH is equivalent to a No. 1 FBH and can be used in place of the response from the No. 1 FBH.

(c)

44% of a No. 3 FBH is equivalent to a No. 2 FBH and can be used in place of the response from the No. 2 FBH.

Each specification also defines a procedure for demonstrating the capability to detect defects at the required sensitivity

levels. In AMS 2630A, this defined procedure is a calibration technique used to set up the ultrasonic instrumentation.

Ultrasonic standards have been designed to establish the performance of the inspection system. Procedures have been

defined by the American Society for Testing and Materials for the manufacture of these ultrasonic reference blocks for

longitudinal wave testing (Ref 2, 3). Finally, the specifications require specific training for the inspectors. For

conformance with AMS 2630A, personnel must be certified to and function within the limits of their levels of

certification as specified by the American Society for Nondestructive Testing (Ref 4). Further details of ultrasonic

inspection procedures are described elsewhere in this Volume.

These specification requirements were designed to control the inspection processes and the quality of the inspection

results. However, several catastrophic failures of major engineering systems (such as the F-111, space shuttle, nuclear

reactors, and the Alaskan pipeline) and the development of advanced materials such as composites were major forces in

the development and application of NDI technology (Ref 5). In concert with these events, a new design method using

linear elastic fracture mechanics (LEFM) required inspection methodology for detecting defects in production and in

service (for a description of LEFM, see Mechanical Testing, Volume 8 of ASM Handbook, formerly 9th Edition Metals

Handbook). Linear elastic fracture mechanics design assumes the presence of structural defects and then allows the

designer to answer the following questions:

•

What is the critical flaw size that will cause failure for a given component subject to service stress and

temperature conditions?

• How long can a precracked structure be safely operated in service?

• How can a structure be designed to prevent catastrophic failure from preexisting cracks?

• What inspections must be performed to prevent catastrophic failure?

The ability to answer these questions forms the basis of nondestructive evaluation (NDE), which involves damage-

tolerant design approaches and is centered on the philosophy of ensuring safe operation in the presence of flaws. The U.S.

Air Force has used damage tolerance analysis, as shown in Fig. 1. The initial component in the as-manufactured condition

is assumed to have a flaw of length a

. This flaw length is based on the manufacturing inspection capability or material

flaw size distribution. The growth of the flaw is predicted for service usage and will reach a critical flaw size, a

, after t

flight hours. The current Air Force philosophy requires an inspection at half the time required for the potential crack to

grow to critical size. This inspection is assumed to detect and remove any flaw of size larger than a

NDE

. The assumption

creates the requirement to determine NDE probability of detection (POD) for this current design practice, as described in

the articles that follow in this Section.

Fig. 1 Crack growth life curve for damage-tolerant design

The driving functions described above caused the NDE/NDI community to evaluate the inspection capabilities. The first

evaluation in the aerospace industry was conducted by Lockheed in the 1970s and was called the "Have Cracks, Will

Travel" program (Ref 6). This program was established to determine if airframe inspection would repeatedly detect cracks

so that engineers could use LEFM philosophy for design. The study concluded that the overall reliability of NDI

performed by the Air Force and evaluated in the program falls below that which has been previously assumed by

established guidelines (Ref 6). The most significant result of the program was that the 90/95 reliability criteria could not

be attained for any flaw size with typical inspection techniques applied by the average technician. Many advancements

have been made in NDE/NDI technology to improve the inspection capability since this study. These technologies are

described throughout this Volume.

References cited in this section

"Ultrasonic Inspection of Product over 0.5 in. (13 mm) Thick," Aerospace Material Specification 2630A,

Society of Automotive Engineers, 1980 (original release 1960)

"Standard Practice for Fabricating and Checking Aluminum

Alloy Ultrasonic Standard Reference Blocks," E

127, Annual Book of ASTM Standards, American Society for Testing and Materials

"Standard Recommended Practice for Fabrication and Control of Steel Reference Blocks Used in Ultrasonic

Inspection," E 428, Annual Book of ASTM Standards, American Society for Testing and Materials

"Recommended Practice, Personnel Qualification and Certification in NDT," SNT-TC-

IA, American Society

for Nondestructive Testing

W. Rummel, Recommended Practice for a Demonstra

tion of Nondestructive Evaluation (NDE) Reliability on

Aircraft Production Parts, Mater. Eval.,Vol 40 (No. 9), Aug 1982, p 922

W.H. Lewis, et al., "Reliability of Nondestructive Inspections--Final Report," Report SA-ALC/MME 76-6-

38-1, United States Air Force, Air Logistics Center, Kelly Air Force Base, 1978

Note cited in this section

Multiple discontinuities are defined in AMS 2630A as two or more indications above the level established

for the class that occur within 16 cm

(1.0 in.

) of the inspected surface.

Introduction to Quantitative Nondestructive Evaluation

Vicki E. Panhuise, Allied-Signal Aerospace Company, Garrett Engine Division

NDE Reliability

The following article in this Section--"Fracture Control Philosophy"--describes the U.S. Air Force philosophy for current

design practices. Damage-tolerant design requires knowledge of the reliability of the inspection technique used to detect

flaws or damage. In the initial stages of using this design approach, a one-number characterization of NDE capability was

in use. The one-number characterization was the minimum crack (flaw) length for which there is a fixed degree of

confidence that at least a fixed probability of cracks will be detected. Typically, the minimum crack length was chosen

such that, at the 95% confidence level (CL), at least 90% of all cracks greater than this length will be detected. The

number is referred to as the 90/95 (POD/CL) crack length.

Probability of detection functions for describing the reliability of an NDE technique have been the subject of many

studies. The ideal inspection system POD function is shown schematically in Fig. 2. All flaws larger than a

NDE

would be

detected all of the time, while all flaws smaller than a

NDE

would not. Obviously, no ideal system exists, and the POD

functions used produce a continuous curve. Figure 3 shows a POD curve for an automated eddy current inspection of

titanium bolt holes. Two confidence level POD curves are shown, 50 and 95%. Berens and Hovey completed a study that

compared POD analysis techniques to determine the optimum calculation method (Ref 7). Additional information

concerning the analysis of NDE data for the determination of reliability is available in the article "NDE Reliability Data

Analysis" in this Section.

Fig. 2 Schematic of probability of detection curves

Fig. 3 POD curve for the automated eddy current inspection of titanium bolt holes

The accuracy of the POD function is dependent on the demonstration program design. The data acquired during the

demonstration program testing can influence the resulting prediction of reliability. For example, consider the cases

presented in Fig. 4, which graphically presents the specimen/crack depth histogram for two case studies. If the design

requirement is such that a

NDE

(that is, 90/95 crack depth) must be 250 μm (10 mils) or less, only the specimens in case

study No. 2 could demonstrate this capability. That is, to demonstrate 90/95 crack size, the specimens fabricated for the

demonstration program must have cracks less than a

NDE

and some larger. If it is assumed that all the flaws were detected

in both cases, the 90/95 crack sizes predicted are as follows:

90/95 crack size

Case study

μm

mils

1 417

16.40