Nondestructive Evaluation of Materials by Infrared Thermography

With national trade barriers falling, causing the expansion of the com petitive global market, the question of quality control has become an essential issue for the 1990s. The time where the promise was to replace a product if it does not work seems to have passed; what is more impor tant now is not so much a reduction in what is going wrong but an increase of what is going right the first time (Feigenbaum 1990). This new trend is sometimes referred to as total quality. Among the many advantages ofthis zero-defect manufacturing policy, we can enumerate (Laurin 1990): superior marketability of wholly de pendable products, enormous gain in productivity, elimination of waste ful cost in replacing poor quality work and retrofitting rejected products from the field. Although total quality is a relatively new and attractive concept for mass products such as cars, consumer electronics and per sonal computers, in many fields, mainly aerospace and military, it has been the rule for years because of security reasons.

Klappentext

This publication presents an up to date coverage of infrared thermography applied in the context of improved industrial activity and quality through automated inspection and control. It puts together concise and complete information on thermal non-destructive evaluation (NDE), a method for testing without damage, not yet available in an integrated, stand-alone format. All concepts discussed are explained in full and many industrial applications of the covered subjects are presented. Although the book is complete by itself extensive references to relevant research papers are given for further reading. Nondestructive Evaluation of Materials by Infrared Thermography is intended for a wide audience. It will help industrial engineers to implement nondestructive evaluation methods on the production line and enlarge their knowledge of industrial inspection techniques. It can also be used as a teaching aid at universities and colleges, especially in materials engineering curricula. Finally research centres will find it valuable as a reference book about thermal NDE.

Inhalt
1 Overview of Nondestructive Evaluation (NDE) Using Infrared Thermography.- 1.1 General Considerations.- 1.2 Active and Passive Approaches in TNDE.- 1.3 New Materials.- 1.4 Detectors for Infrared Imaging.- 1.5 TNDE: Pros and Cons.- 2 Theoretical Aspects.- 2.1 Radiometry.- 2.2 Heat Transfer Modelling.- 3 Experimental Apparatus.- 3.1 Description of the System and Intended Use.- 3.2 Acquisition Process: Signal Restoration.- 3.3 System Calibration.- 4 External Thermal Stimulation: Methods and Image Processing.- 4.1 General Considerations.- 4.2 Study of Graphite Epoxy Composites: Procedures, Investigation, Processing.- 4.3 Study of Aluminium Laminates: Procedures, Investigation, Processing.- 4.4 Automatic Defect Detection.- 5 Internal Thermal Stimulation: Methods and Image Processing.- 5.1 General Considerations.- 5.2 Case Study I: Evaluation of Corrosion Damage to Pipes.- 5.3 Case Study II: Inspection of Jet Turbine Blades.- 6 Quantitative Analysis of Delaminations.- 6.1 General Considerations.- 6.2 The Inverse Problem.- 6.3 Experimental Procedure: Thermogram Processing.- 6.4 Discussion on the Quantitative Characterization Procedure.- 7 Inspection of Materials With Low Emissivity by Thermal Transfer Imaging.- 7.1 General Considerations.- 7.2 Thermal Transfer Imaging.- 7.3 Physical Behaviour of Thermal Transfer Imaging Technique.- 7.4 Experimental Results.- 8 Thermal Diffusivity Measurements of Materials.- 8.1 General Considerations.- 8.2 Classical Thermal Diffusivity Measurement Method.- 8.3 Diffusivity Measurement Method Based on the Laplace Transform.- 8.4 Diffusivity Measurement Method Based on Phase Measurement.- 9 Thermal Tomography.- 9.1 General Considerations.- 9.2 Method.- 9.3 Some Results.- 10 Thermal NDE of Nonplanar Surfaces.- 10.1 General Considerations.- 10.2 Principle of Surface Curvature Correction.- 11 Applications of Infrared Thermography to High Temperatures.- 11.1 Detection of Rolled-in Scale on Steel Sheets.- 11.2 Thermal Inspection of High Temperature Industrial Structures.- Appendix A Computer Model.- Appendix B Smoothing Routine.- Appendix C Parabola Computation.- Appendix D Higher Order Gradient Computation Based on the Roberts Gradient.- References.