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DEEC

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Non-destructive technique for Control, Characterization and Visualisation

Name of the Curricular Unit: Non-destructive technique for Control, Characterization and Visualisation

Lecturer: Jaime Santos (jaime@deec.uc.pt) 

Syllabus:

1 - Background on the ultrasound: Understanding ultrasound. Concept of piezoelectricity. Materials used in the generation of ultrasound.  Fields of application. 2 - Selection of probes: choice of materials and construction aspects: Choice of piezoelectric materials taking into account the applications. Constructive aspects. Immersion and contact probes. Transmitting and receiving probes. Focused and tilted probes. Rayleigh waves and Lamb waves. Excitation modes: continuous and pulsed regime. 3 - Physical quantities associated with ultrasound: Concepts of displacement, strain, pressure, vibration and displacement velocities. Concept of isotropy and anisotropy. Elastic constants and Lamé constants. Wave equation. Concept of acoustic  impedance. Propagation in media with interfaces. Conversion modes. 4-Characterization of  ultrasonic transducers: Near field and far field concept. Sommerfield and Green conditions . Radiation diagrams. Aperture  angle. Array of transducers concept. Mechanical and electronic beam focusing. Project of an array. Electronic focusing and beam tilt: the notion of delay lines. 5 - ultrasonic visualization techniques: A-scan, B-scan and C-scan display. Diagram of echoes. Fields of application of each display type. Potential of each display. Simple ways of implementation. Information contained in each display type.

Evaluation method: 

Lab (50%); Exam (50%)