Sampling Phased Array (SPA)

New solution to existing testing problems

Although conventional phased array technology significantly reduces the mechanical complexity in the handling of an ultrasonic testing system, in order to achieve the high probability of detection expected whilst covering an entire cross section, the quality of Sector-Scan images must be improved. This necessitates an increase in the number of beam angles and focal depths used, and in doing this the overall inspection time is increased, which may not be practicable. The results can be replicated or even improved through the use of sampling phased array (SPA) with one single insonification.

SPA delivers major improvements in the quality of ultrasonic inspections and in ease of interpretation. It permits the meaningful reconstruction of defects at high inspection speeds and enables the inspection of anisotropic materials. In addition to this, this non-destructive testing (NDT) technique achieves considerable results in producing real images of flaws in materials.

SPA technology also offers new opportunities for the development and application of ultrasonic testing systems.

Benefits of sampling phased array at a glance

Using our sampling phased array inspection services, you gain:

  • Increased test speed.
  • Improved resolution and higher probability of detection.
  • Quantitative imaging in real-time.
  • Easier interpretation of inspection results.
  • Enhanced ability to inspect non-homogeneous anisotropic materials such as carbon fibers, stainless steel and dissimilar welds.
  • More convenient inspection from the logistical point of view.
  • TÜV Rheinland´s exclusive one-stop shop services.

SPA approach

  • One transducer element produces a single shot.
  • The returning echo signals are captured by each one of the transducer elements.
  • The stored signals create an information matrix.
  • Each row in the matrix contains all the essential information required to produce a reconstructed image.

Signal to noise ratio issues and the detection of planar flaws with distinct directivity patterns can be avoided due to the simultaneous transmission of all elements combined into a virtual point source or linear source. This approach allows a complete sector-scan reconstruction with any scan (beam) angle and with arbitrary focal points for each transmission cycle. Suitable real-time signal processing methods are available today for integrated highly-efficient parallel computing.

The reconstruction capability of A-Scan images is of utmost importance for the Sampling Phased Array technique in order to comply with existing codes, standards and regulations for NDT until standards also cover this technique.

SPA application range

  • New weld construction of pressure vessels and piping.
  • In-service inspection of welds.
  • Inspection of stainless steels.
  • Inspection of turbine components such as retaining rings and blade attachments.
  • Accurate detection and sizing of hydrogen induced cracking.
  • Assessment of hydrogen damage.