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For those interested in TFM applications and its validation in CIVA, read this paper from Dr. Souad BANNOUF, presented at ECNDT 2018 and dealing with the characterization of planar defects in a circular weld with TFM.

This paper reports results from a feasibility study carried out by EXTENDE and EDF CEIDRE about characterization of planar defects located in a welded cylindrical specimen with the Total Focusing Method (TFM). First, the characterization of EDM notches in a welded part with a complex internal profile is evaluated by simulation. The simulated results are compared to experimental ones and show good agreement. A characterization procedure for planar defects with TFM is proposed. It is applied to fatigue cracks and shows convincing results. Detection but also characterization of planar breaking backwall defects seem possible with TFM when using LL direct mode reconstruction of the region of interest. However, corner echo mode reconstruction may also complete and confirm the defect characterization depending on some conditions detailed in this paper (probe positioning, geometry knowledge, …).

To read the full article, you can visit our article library here.

The EXTENDE team

Here is a very interesting article from Mr. Paul Holloway, P. Eng.,  published in the CINDE journal and dealing with “Structural UT: Variables Affecting Attenuation and Review of the 2 dB per Inch Model”

The North American standards for welded steel construction, CSA W59[1] and AWS D1.1[2], use an approximation for ultrasonic attenuation of 2dB/in. This approximation is based on the use of large, low frequency transducers which are not always well-suited to the wide range of weld thicknesses and geometries used in the codes. This paper documents computer simulations and experimental results performed to gauge the suitability of this linear factor to approximate a non-linear  phenomenon. Additionally, models of smaller transducers and higher frequencies are included to study their effect. This is performed to determine how alternate criteria and procedures may be developed to retain the same levels of sensitivity but expand the range of transducers beyond that currently permitted.”

To read the full article, you can visit our article library here.

The EXTENDE team