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Composite testing - Coggle Diagram

- - - - backwall echo: hit far end of the specimen, the sound wave will return as an echo.
      - Travel time of defect: measure the location of the defect from surface
      - Defect depth = (transit time/2) x velocity
    - - use shear sound waves (transverse sound waves)
      - not orientate parallel to the surface of the part
      - Flaws are more easily detected: wedges that are attached to probes which cause refraction of sound beam at different angle
    - - B scan: cross-sectional view
      - C scan: top view of scanned part
      - A scan: plot of signal amplitude against time
    - - two transducers: one to produce sound wave, another to receive it
      - Advantages: Less affected by sound attenuation (loss of ultrasonic energy). Sound waves only travel through thickness once
      - Disadvantages: two sided access to part is required.
        Unable to reveal the depth of defect.
        Bulky equipment and hence not suitable for field inspection.
    - - Advantages
        
        able to detect deep defects .
        
        able to determine defect size and shape
        
        relatively safe
      - Disadvantages
        
        less suitable for inspection of large surface
        
        flaw located close to surface is hidden by pulse signal ; not suitable for very thin parts
        
        calibration standard are required
- - - - span length-to-specimen thickness ratio of 4.0
      - specimen length = thickness x 6
      - specimen width = thickness x 2.0