Review of progress, QNDE

CIVA: an expertise platform for simulation and processing NDT data.

A refinement of the Kirchhoff approximation to the scattered elastic fields.

A system model for ultrasonic NDT based on the Physical Theory of Diffraction (PTD).

A conformable phased array device has been developed for the inspection of components with irregular surface geometry This low‐cost device uses a standard linear phased array coupled to the pipe‐work surface via a water‐filled, low‐loss membrane The membrane coupled device allows rapid scanning of components with irregular surfaces without the need for multiple angled probes and time consuming mechanical scanning Comparison testing between the conformable array and conventional rigid wedge technology demonstrates that internal noise within the membrane coupled device housing degrades inspection performance Further development of the device has been completed, significantly decreasing this noise and improving device performance

Inspection of components with irregular surfaces using a conformable ultrasonic phased array

A model coupling viscoelastic and multiple‐scattering losses is developed to predict ultrasonic attenuation in unidirectional fiber reinforced composite of high fiber volume fraction. Complex‐valued stiffness constants accounting for viscoelasticity are inserted in classical multiple‐scattering theory. Waves of various polarities (SH, SV, L) relatively to the fiber direction are considered. SH waves only require a scalar treatment, whereas the others require a vector treatment accounting for mode‐conversions. Comparisons of predicted attenuation coefficients with experimentally measured ones validate the model.

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Modeling of Ultrasonic Attenuation in Uni‐Directional Fiber Reinforced Composites Combining Multiple‐Scattering and Viscoelastic Losses

The ultrasonic simulation tools gathered in the CIVA software include beam and defects computations. The calculations apply propagation and scattering models based on semi-analytical kernels and numerical integration. Over the years a large amount of experimental comparisons have been carried out using CIVA in the framework of studies dedicated to different industrial applications, either at CEA or by CIVA users. In parallel CEA has participated to various international modeling benchmarks in particular organized by WFNDEC (World Federation of NDE Centers). To go further a long-term validation work is being done at CEA in order to precisely quantify the level of reliability of the predictions, and accurately define the domain of applicability of the models. This work is mainly based on comparisons between CIVA simulation results and experimental measurements. In this communication we present the validation procedure which is been adopted. We report the results obtained on various canonical configurations: reference reflectors SDHs, FBHs, corner echoes on notches. The validations are complemented by theoretical considerations about hypotheses and approximations of the models allowing drawing conclusions on the models validity.

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Validation of CIVA ultrasonic simulation in canonical configurations

The CIVA software developed at the French Atomic Energy Commission for processing and simulating NDT data includes tools for modelling the whole ultrasonic inspection of a component in which virtual defects are positioned. In this paper, Kirchhoff’s approximation and reciprocity principle were applied to predict the reception by the transducer of waves scattered by the defect. Results given and discussed are those obtained for the various problems of the 2005 UT benchmark modelling session. These results concern the echographic responses of side drilled holes and cracks using immersed inspection techniques.

Results of the 2005 UT Modelling Benchmark Obtained with the CIVA Software Developed at the CEA

The 2013 Ultrasonic Testing (UT) modeling benchmark concerns direct echoes from side drilled holes (SDH), flat bottom holes (FBH) and corner echoes from backwall breaking artificial notches inspected with a matrix phased array probe. This communication presents the results obtained with the models implemented in the CIVA software: the pencilmodel is used to compute the field radiated by the probe, the Kirchhoff approximation is applied to predict the response of FBH and notches and the SOV (Separation Of Variables) model is used for the SDH responses. The comparison between simulated and experimental results are presented and discussed.

Results of the 2013 UT modeling benchmark obtained with models implemented in CIVA

The ultrasonic TOFD (Time of Flight Diffraction) Technique is commonly used to detect and characterize disoriented cracks using their edge diffraction echoes. An overview of the models integrated in the CIVA software platform and devoted to TOFD simulation is presented. CIVA allows to predict diffraction echoes from complex 3D flaws using a PTD (Physical Theory of Diffraction) based model. Other dedicated developments have been added to simulate lateral waves in 3D on planar entry surfaces and in 2D on irregular surfaces by a ray approach. Calibration echoes from Side Drilled Holes (SDHs), specimen echoes and shadowing effects from flaws can also been modelled. Some examples of theoretical validation of the models are presented. In addition, experimental validations have been performed both on planar blocks containing calibration holes and various notches and also on a specimen with an irregular entry surface and allow to draw conclusions on the validity of all the developed models.

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Sébastien Lonné

Papers

Modeling of Ultrasonic Attenuation in Uni‐Directional Fiber Reinforced Composites Combining Multiple‐Scattering and Viscoelastic Losses

Validation of CIVA ultrasonic simulation in canonical configurations

Results of the 2005 UT Modelling Benchmark Obtained with the CIVA Software Developed at the CEA

Results of the 2013 UT modeling benchmark obtained with models implemented in CIVA

Recent modelling advances for ultrasonic TOFD inspections