Applications of ultrasound in analysis, processing and quality control of food: A review

Piezoelectric wafer active sensors may be applied on aging aircraft structures to monitor the onset and progress of structural damage such as fatigue cracks and corrosion. The state of the art in piezoelectric-wafer active sensors structural health monitoring and damage detection is reviewed. Methods based on (a) elastic wave propagation and (b) the Electro–Mechanical (E/M) impedance technique are cited and briefly discussed. For health monitoring of aging aircraft structures, two main detection strategies are considered: the E/M impedance method for near field damage detection, and wave propagation methods for far-field damage detection. These methods are developed and verified on simple-geometry specimens and on realistic aging aircraft panels with seeded cracks and corrosion. The experimental methods, signal processing, and damage detection algorithms are tuned to the specific method used for structural interrogation. In the E/M impedance method approach, the high-frequency spectrum, representative of the structural resonances, is recorded. Then, overallstatistics damage metrics can be used to compare the impedance signatures and correlate the change in these signatures with the damage progression and intensity. In our experiments, the (1 � R 2 ) 3 damage metric was found to best fit the results in the 300–450 kHz band. In the wave propagation approach, the pulse-echo and acousto-ultrasonic methods can be utilized to identify the additional reflections generated from crack damage and the changes in transmission phase and velocity associated with corrosion damage. The paper ends with a conceptual design of a structural health monitoring system and suggestions for aging aircraft installation utilizing active-sensor arrays, data concentrators, wireless transmission, and a health monitoring and processing unit.

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Piezoelectric Wafer Embedded Active Sensors for Aging Aircraft Structural Health Monitoring

http://www.mkckorea.com/catalog/qseeman/hc-200_ref8.pdf

Corrosion Monitoring of Reinforced Concrete Structures - A Review

Bonded repair of composite aircraft structures: A review of scientific challenges and opportunities

OH-radical formation by ultrasound in aqueous solution--Part II: Terephthalate and Fricke dosimetry and the influence of various conditions on the sonolytic yield.

Introduction. The propagation of low amplitude ultrasound. Ultrasonic characterization. Ultrasonic transducers. The principles of ultrasonic testing. Ultrasonic testing equipment. Ultrasonic flaw detection. Flaw sizing in metals. The testing of metals. The examination of non-metals and adhesive bonds. Training, certification and standards. Further reading. Appendices.

Ultrasonic methods of non-destructive testing

Preface. Introduction. Fundamental theory. Magnetic methods. Eddy current principles. Eddy current methods. More advanced eddy current testing methods. Microwave methods. Miscellaneous methods. Appendix. References. Index.

Jack Blitz

Papers

Ultrasonic methods of non-destructive testing

Electrical and Magnetic Methods of Nondestructive Testing

Fundamentals of Ultrasonics

Elements of Acoustics

Ultrasonics: methods and applications