COMPOSITE DEFECTS AND THEIR DETECTION

UNESCO – EOLSS SAMPLE CHAPTERS MATERIALS SCIENCE AND ENGINEERING – Vol. III – Composite Defects and Their Detection - R. A. Smith ©Encyclopedia of Life Support Systems (EOLSS) COMPOSITE DEFECTS AND THEIR DETECTION R. A. Smith Structural Materials Centre, QinetiQ Ltd, Cody Technology Park, Farnborough, UK Keywords: Non-destructive testing, composites, ultrasound, thermography, radiography, acoustics, holography, shearography, interferometry. Contents 1. Introduction 1.1. Scope 1.2. Defects in Composites 1.3. Significance of Defects in Composites 1.4. Detection methods 2. Types of Defect in Composites 2.1. Manufacturing Defects 2.2. In-service Defects 3. Ultrasonic Inspection Methods 3.1. Basic Ultrasonics 3.2. Choice of Frequency 3.3. Defect Detection and Characterization 3.4. Ultrasonic Imaging Techniques 3.5. Production Inspection Techniques 3.6. In-service Inspection Techniques 3.7. Specialist Ultrasonic Techniques 4. Low-frequency Vibration Methods 4.1. Global Assessment 4.2. Local Assessment 5. Acoustic Emission and Acousto-Ultrasonics 6. X-Radiography 7. Optical Methods 8. Thermal Methods 8.1. Thermal Imaging 8.2. Pulsed Thermography 8.3. Lock-in Thermography Acknowledgments Glossary Bibliography Biographical Sketches Summary Defects can inadvertently be produced in composite materials either during the manufacturing process or in the course of the normal service life of the component. The most significant defects in monolithic structures are porosity, caused by incorrect manufacture, and impact damage during in-service use. For sandwich structures with honeycomb cores the presence of bond failure or core crushing is equally significant.

COMPOSITE DEFECTS AND THEIR DETECTION

Documents

nondestructive testing

composites

ultrasound

thermography

radiography

acoustics

holography

shearography