TWI Industrial Member Report Summary 966/2010
By M Weston
In recent years the non-destructive testing (NDT) industry has seen a sharp rise in the use of ultrasonic arrays. Typically each element of an array transducer is controlled independently using parallel transmission/reception channels, which make beam steering and focusing possible. With ever increasing computing power it is now feasible to develop an ultrasonic technique which utilises the post-processing of data. The full matrix capture (FMC) concept has been developed in recent years, and the technology is now at a stage where it can be harnessed for industrial applications such as mainstream ultrasonic weld inspection and long range ultrasonic examination.
The FMC technique is based on the concept of transmitting on a single array element and receiving on all elements, then repeating this with the adjacent single element transmitting. The process repeats until all elements have transmitted. By post-processing the full matrix of raw data from every transmit/receive combination, an image can be reconstructed where all points within the insonified area are in focus. This differs from current phased array techniques used in industry which insonify the region of interest using predefined, fixed delay laws.
The FMC technique potentially offers higher resolution and increased sensitivity compared with conventional phased array (PA) techniques, yielding more realistic pictorial images of flaws. If operators can determine the shape and character of a flaw they will be in a better position to assess its morphology. Improved flaw sizing will facilitate more accurate fitness for service assessments, leading to enhanced levels of safety and reduced cost for industry.
- Develop the algorithms to implement the FMC concept.
- Demonstrate the method by detecting and sizing a set of flaws designed to illustrate the benefits of the FMC implementation, in comparison with conventional focused/steered array implementation.