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Novel Ultrasonic Testing Inspection Capability for Sizing of Rough Cracks

Project Code: 33596


  • Develop a number of novel features/techniques to enhance the sizing capability of full matrix capture (FMC) for the inspection of rough cracks (Ra = 50μm or greater) in austenitic or ferritic steel components.
  • Manufacture/procure a number of realistic rough crack samples, including at least one stress corrosion crack sample.
  • Perform simulations and experimental trials as appropriate to develop suitable FMC inspection setup/technique for sizing of rough crack flaws.
  • Using the European Network for Inspection and Qualification (ENIQ) methodology for guidance, develop a capability statement demonstrating the sizing capability for FMC for inspection of rough cracks.

Project Outline

FMC ultrasonic inspection offers a number of benefits over existing ultrasonic inspection techniques, to support fitness for service assessments, including amongst others: detection and sizing of near-vertical and off-specular planar flaws; fully focussed inspection through complex-geometry; and ability to interrogate the inspection volume using a range of wave modes from a single scan.

This project will develop a number of novel techniques and apply these to TWI’s FMC inspection software package, Crystal, in order to demonstrate sizing accuracy of FMC for rough cracks (Ra = 50μm or greater) in austenitic or ferritic steel. Novel FMC features/techniques to be developed within this proposed scope of work include:

  • Development of a novel technique to differentiate corner trap signals when masked by geometric reflections. The intended approach will use differences in ultrasonic interaction between a corner trap signal and that from a geometric reflection to enable corner trap signals to be detected and used along with the tip response for flaw sizing.
  • Development of an innovative crack tip enhancement feature to increase sensitivity to crack tip response from the major face of a rough crack. Tip and facet responses from a rough crack are typically an order of magnitude (or more) weaker than those of the corner trap, geometric reflection, or specular response from the major face of the flaw. This algorithm will exploit differences in the ultrasonic interaction between a tip/facet and that from material grain structure, corner trap or geometric reflections to enhance the signal to noise ratio of a crack tip/facet.

Relevant Industry Sectors

Benefits to Industry

The project outcomes will improve confidence in flaw detection and sizing accuracy, and provide documented evidence of capability for use by industry during inspection procedure qualification to reduce the time and cost for qualification using advanced ultrasonic testing.


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