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Non-destructive evaluation (A tool for design, manufacturing and service)
=Book Review Non-destructive evaluation (A tool for design, manufacturing and service) Don E. Bray and Roderick K. Standley
McGraw-Hill, New York 1989 ISBN 0-07-007351- 1 (581pp £34.95) For a long time the NDT world has been short of a good text book suitable for use by undergraduates with a fully developed scientific and mathematical background. At last is seems we may have one. The book is divided into six sections and 35 chapters covering design and probability of failure, followed by sections on ultrasonic testing, magnetic flux leakage, radiography, penetrant testing, and eddy current testing. Section 1 discusses typical flaw distributions and probability of detection associated with a particular technique. Having detected flaws, fracture mechanics and lifetime of components are considered. Another factor in this complex equation is selection of a particular NDT technique to achieve an appropriate cost-benefit ratio. The fact that these topics are considered first in the book (rather than as an afterthought) firmly identifies NDE as an important consideration in design and component/system reliability. The section on ultrasonic testing develops systematically from the basic theory of elastic wave propagation, reflection and mode conversion, even considering Lamb and Rayleigh waves, which some might regard as of more esoteric interest. Piezoelectric transducers are considered first, leading into a discussion of radiation patterns. Passing reference is also made to
EMATs and laser generation of ultrasound.
with the problems of demagnetization.
A chapter on A-scan ultrasonics considers the detection of a range of defects considering likely ehco patterns and such things as DAC and material attenuation. Defect size is dealt with by the 6 dB down method and then moves on to review imaging without considering DGS methods (an omission?). A useful chapter considers the effects of stress and texture on ultrasonic velocity.
On the part IV and the consideration of X and ~-ray imaging, inspection systems and source/film methods. The section on penetrant testing is short but it does develop the basic theory of surface tension capillary action and considers the physics of defect visibility as well as practical aspects including fully automated measurement systems.
Part III considers flux leakage, perhaps reflecting the bias of one of the authors towards pipe inspection. The physics of magnetic circuits and magnetic materials is dealt with in some detail, and some might think it goes too far into vector field theory. However, the test quickly moves back to consider the practicalities of tube magnetization. Consideration is given to yoke magnetization in MPI, magnetization of tubular components, the magnetization of wire rope, and magnetic inspection 'pigs'. Having considered the ideas and theory associated with the magnetization of the materials the leakage of flux is considered in some detail and should prove useful source material for those interested in this area of NDT. The text then moves to devices for flux leakage measurement and MPI, ending
Eddy current techniques come last and are developed in a similar way, considering basic theory and impedance plane methods. I think users of eddy current methods may be a little disappointed with this section but overall, I think, the authors are to be congratulated. The book is not perfect, some things are left out, but I have dipped into it over a period of time and have been pleased to find the basic ideas and applications of NDT between two covers. Some will find some sections too advanced, but the text does also deal with a wide range of practical problems and even has a good selection of numerical examples to try. We have a first rate text book for NDT professionals - we should make use of it.
R. Hill Nottingham Polytechnic, UK
Reliability in nondestructive testing Edited by C. Brook and P.D. Hanstead
Pergamon Press, Oxford, UK, 1989 (ix + 510pp £65.00, US$120.00) All NDT is, in a sense, about reliability of materials, but the aim of the 27th annual British
188
conference on nondestructive testing 1988 was to consider the reliability of NDT.
The conference proceedings contains papers which definitely consider aspects of NDT reliability
NDT International June 1990
McGraw-Hill, New York 1989 ISBN 0-07-007351- 1 (581pp £34.95) For a long time the NDT world has been short of a good text book suitable for use by undergraduates with a fully developed scientific and mathematical background. At last is seems we may have one. The book is divided into six sections and 35 chapters covering design and probability of failure, followed by sections on ultrasonic testing, magnetic flux leakage, radiography, penetrant testing, and eddy current testing. Section 1 discusses typical flaw distributions and probability of detection associated with a particular technique. Having detected flaws, fracture mechanics and lifetime of components are considered. Another factor in this complex equation is selection of a particular NDT technique to achieve an appropriate cost-benefit ratio. The fact that these topics are considered first in the book (rather than as an afterthought) firmly identifies NDE as an important consideration in design and component/system reliability. The section on ultrasonic testing develops systematically from the basic theory of elastic wave propagation, reflection and mode conversion, even considering Lamb and Rayleigh waves, which some might regard as of more esoteric interest. Piezoelectric transducers are considered first, leading into a discussion of radiation patterns. Passing reference is also made to
EMATs and laser generation of ultrasound.
with the problems of demagnetization.
A chapter on A-scan ultrasonics considers the detection of a range of defects considering likely ehco patterns and such things as DAC and material attenuation. Defect size is dealt with by the 6 dB down method and then moves on to review imaging without considering DGS methods (an omission?). A useful chapter considers the effects of stress and texture on ultrasonic velocity.
On the part IV and the consideration of X and ~-ray imaging, inspection systems and source/film methods. The section on penetrant testing is short but it does develop the basic theory of surface tension capillary action and considers the physics of defect visibility as well as practical aspects including fully automated measurement systems.
Part III considers flux leakage, perhaps reflecting the bias of one of the authors towards pipe inspection. The physics of magnetic circuits and magnetic materials is dealt with in some detail, and some might think it goes too far into vector field theory. However, the test quickly moves back to consider the practicalities of tube magnetization. Consideration is given to yoke magnetization in MPI, magnetization of tubular components, the magnetization of wire rope, and magnetic inspection 'pigs'. Having considered the ideas and theory associated with the magnetization of the materials the leakage of flux is considered in some detail and should prove useful source material for those interested in this area of NDT. The text then moves to devices for flux leakage measurement and MPI, ending
Eddy current techniques come last and are developed in a similar way, considering basic theory and impedance plane methods. I think users of eddy current methods may be a little disappointed with this section but overall, I think, the authors are to be congratulated. The book is not perfect, some things are left out, but I have dipped into it over a period of time and have been pleased to find the basic ideas and applications of NDT between two covers. Some will find some sections too advanced, but the text does also deal with a wide range of practical problems and even has a good selection of numerical examples to try. We have a first rate text book for NDT professionals - we should make use of it.
R. Hill Nottingham Polytechnic, UK
Reliability in nondestructive testing Edited by C. Brook and P.D. Hanstead
Pergamon Press, Oxford, UK, 1989 (ix + 510pp £65.00, US$120.00) All NDT is, in a sense, about reliability of materials, but the aim of the 27th annual British
188
conference on nondestructive testing 1988 was to consider the reliability of NDT.
The conference proceedings contains papers which definitely consider aspects of NDT reliability
NDT International June 1990