Non-Destructive Evaluation Series – serie

Ultrasonic Methods of Non-Destructive Testing covers the basic principles and practices of ultrasonic testing, starting with the basic theory of vibration and propagation, design and properties and probes, and then proceeding to the principles and practice of the various ultrasonic techniques for different types of components and structures, both metallic and non-metallic. The design and operation of various types of equipment are covered and references to appropriate national and international standards are provided. Numerous applications are discussed comprehensively and special attention is paid to latest developments. A large number of references is provided so as to enable the reader to obtain further information.

Microwave and millimeter-wave non-destructive testing and evaluation (NDT&E) is generally understood to mean using high-frequency electromagnetic energy to inspect and characterize materials and structures. In spite of possessing some distinct advantages in certain applications to other NDT&E techniques, microwave NDT&E has only found compared limited practical application during the past 45 years. These advantages include lack of a need for contact between the sensor and the object being inspected, the ability to penetrate dielectric materials, and superior sensitivity to certain material constituents and flaws. One factor contributing to this minimal acceptance by the NDT &E community has been a generally poor understanding in this community of the theory and practice that underlie the technology. This situation exists partly because of a paucity of microwave NDT&E textbook and reference material. Some chapters, reviews, and books aimed at filling this need have been published in the past but, for the most part, this material is based on the use of older microwave technology. However, during the past ten years great strides have been made in ternlS of the cost, size, and ease of use of microwave components. In addition, recent advances in modeling and measurement techniques have expanded the range of applications for microwave NDT&E. Such applications include inspecting modern materials such as composites, detecting and characterizing surface flaws, and evaluating the compressive strength of cement structures. These advances have created an urgent need for up-to-date textbook material on this subject.

Industrial radiography is a well-established non-destructive testing (NDT) method in which the basic principles were established many years ago. However, during 1993-95 the European Standards Organisa­ tion (CEN) commenced drafting many new standards on NDT including radiographic methods, and when completed these will replace national standards in all the EC member countries. In some cases these standards vary significantly from those in use in the UK at present. These CEN standards are accepted by majority, not unanimous voting, so they will become mandatory even in countries which vote against them. As most are likely to be legal by the time this second edition is published, they are described in the appropriate places in the text. The most important new technical development is the greater use of computers in radiology. In the first edition, computerized tomography was only briefly mentioned at the end of Chapter 11, as it was then largely a medical method with only a few equipments having found a place in industrial use. The method depends on a complex computer program and a large data store. Industrial equipments are now being built, although their spread into industry has been slow. Computer data storage is also being used for radiographic data. Small computers can now store all the data produced by scanning a radiographic film with a small light-spot, and various programs can be applied to these data.

This book is intended to help satisfy an urgent requirement for up-to­ date comprehensive texts at graduate and senior undergraduate levels on the subjects in non-destructive testing (NDT). The subject matter here is confined to electrical and magnetic methods, with emphasis on the widely used eddy current and magnetic flux leakage methods (including particle inspection), but proper attention is paid to other techniques, such as microwave and AC field applications, which are rapidly growing in importance. Theoretical analyses relating to the various methods are discussed and the depths of presentation are often governed by whether or not the information is readily available elsewhere. Thus, for example, a considerable amount of space is devoted to eddy current theory at what the author considers to be a reasonable standard and not, as usually experienced, in either a too elementary manner or at a level appreciated only by a postgraduate theoretical physicist. The inclusion of the introductory chapter is intended to acquaint the reader with some of the philosophy of NDT and to compare, briefly, the relative performances of the more important methods of testing.

Microwave and millimeter-wave non-destructive testing and evaluation (NDT&E) is generally understood to mean using high-frequency electromagnetic energy to inspect and characterize materials and structures. In spite of possessing some distinct advantages in certain applications to other NDT&E techniques, microwave NDT&E has only found compared limited practical application during the past 45 years. These advantages include lack of a need for contact between the sensor and the object being inspected, the ability to penetrate dielectric materials, and superior sensitivity to certain material constituents and flaws. One factor contributing to this minimal acceptance by the NDT &E community has been a generally poor understanding in this community of the theory and practice that underlie the technology. This situation exists partly because of a paucity of microwave NDT&E textbook and reference material. Some chapters, reviews, and books aimed at filling this need have been published in the past but, for the most part, this material is based on the use of older microwave technology. However, during the past ten years great strides have been made in ternlS of the cost, size, and ease of use of microwave components. In addition, recent advances in modeling and measurement techniques have expanded the range of applications for microwave NDT&E. Such applications include inspecting modern materials such as composites, detecting and characterizing surface flaws, and evaluating the compressive strength of cement structures. These advances have created an urgent need for up-to-date textbook material on this subject.

Industrial radiography is a well-established non-destructive testing (NDT) method in which the basic principles were established many years ago. However, during 1993-95 the European Standards Organisa­ tion (CEN) commenced drafting many new standards on NDT including radiographic methods, and when completed these will replace national standards in all the EC member countries. In some cases these standards vary significantly from those in use in the UK at present. These CEN standards are accepted by majority, not unanimous voting, so they will become mandatory even in countries which vote against them. As most are likely to be legal by the time this second edition is published, they are described in the appropriate places in the text. The most important new technical development is the greater use of computers in radiology. In the first edition, computerized tomography was only briefly mentioned at the end of Chapter 11, as it was then largely a medical method with only a few equipments having found a place in industrial use. The method depends on a complex computer program and a large data store. Industrial equipments are now being built, although their spread into industry has been slow. Computer data storage is also being used for radiographic data. Small computers can now store all the data produced by scanning a radiographic film with a small light-spot, and various programs can be applied to these data.