Review of progress, QNDE

A review of ultrasonic testing applications in additive manufacturing: Defect evaluation, material characterization, and process control.

The X-ray radiographic simulation software SINDBAD, has been developed to help the design stage of radiographic systems or to evaluate the efficiency of i mage processing techniques, in both medical imaging and Non-Destructive Evaluation (NDE) industrial fields . This software can model any radiographic set-up, including the X-ray source, the beam interaction inside the object represented by its Computed Aided Design (CAD) model, and the imaging process in the detector. For each step of the virtual experimental bench, SINDBAD combines different modelling modules, accessed via Graphical User Interfaces (GUI), to provide realistic synthetic images. In this paper, we present an overview of all the functionalities which are available in SINDBAD, with a complete description of all the physics taken into account in models as well as the CAD and GUI facili ties available in many computing platforms. We underline the different modules usable for different applic ations which make SINDBAD a multi-purposed and scalable X-ray simulation tool.

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SINDBAD : a realistic multi-purpose and scalable X-ray si mulation tool for NDT applications

The fundamental obstacle to characterising accurately the defects in austenitic welds is the distortion of the sound field due to the anisotropic inhomogeneous material. This paper describes the development of the next generation of ultrasonic procedures which use phased array techniques and models to account for the distortion of the sound field, such that the detection, positioning and sizing of defects is improved in comparison to current capabilities. Each stage of the procedure development is described, along with the issues and obstacles which must be overcome. The electron back-scatter diffraction technique is used to evaluate the texture of the weld and then the microstructural information is input to a model capable of propagating ultrasonic waves through the anisotropic inhomogeneous medium. With knowledge of the distortion, a strategy of adapting the focal laws using time reversal concepts to improve sensitivity was developed.

http://www.dissimilarweld.co.uk/publications/DISSIMILAR_pt1_(Dec,_2009).pdf

Microstructural quantification, modelling and array ultrasonics to improve the inspection of austenitic welds

Auto-focusing along with dynamic depth focusing (DDF) would be very valuable to inspect arbitrarily shaped parts when operating with wedges or with other coupling media to avoid the burden of computing and setting the correct focal laws while still getting the best possible resolution at all depths. This work proposes a three-step procedure to perform the auto-focusing function with DDF in real time. First, the part geometry is estimated by the first echo time-of-arrival following one of several possible strategies: pulse-echo, pitch-catch, or plane wave. These are analyzed with regard to their performances and acquisition time, giving closed formulae to get the coordinates of interface points. After a curve fitting and extrapolation process, a virtual array that operates in a homogeneous medium is computed, avoiding the complications of refraction at the interface and allowing operation with already known focusing hardware. This hardware is initialized with the set of focusing parameters adapted to the estimated probe- part geometry, and ensures that all received samples are in focus. Using a standard computer, the auto-focusing procedure currently takes about 2 s to perform. Experiments carried out under different conditions validate the proposed technique.

Automatic dynamic depth focusing for NDT

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

The CEA LIST develops the simulation platform CIVA which includes UT, ECT and RT modules. UT simulation is based on semi-analytical models of the ultrasound propagation and scattering and allows to address a wide range of realistic and complex configurations. Over successive versions, CIVA is enriched by the results of the latest modelling research performed by CEA LIST and its partners. This communication focuses on the recent advances and the current trends in CIVA ultrasonic modelling. One important issue concerns flaw scattering and work is being done in order to integrate in the models complex echo mechanisms not yet taken into account. Thus, contribution of head or creeping waves near critical angles to breaking cracks corner echoes, have been recently integrated in to the echo-formation modelling. In parallel, a hybrid model combining finite element code around the defect and semi-analytical modelling of the beam propagation has been developed. Another work in progress concerns the modelling of noise due to ultrasound scattering by microstructure in polycrystalline materials. At last the development of tools dedicated to array techniques remains a major axis of development. On these different topics the new developments are presented and illustrated by examples of applications and validations.

Recent advances and current trends of ultrasonic modelling in CIVA

In this communication we briefly present the phased array simulation tools developed at the CEA in the aim of driving delays laws, predicting ultrasonic beams, simulating and processing acquired data. These tools allow to manage NDT inspections in complex configurations. We present some examples on such configurations illustrating the interest and reliability of simulation.

http://ieeexplore.ieee.org/iel5/8480/26730/01193503.pdf

Simulation of phased array techniques for realistic NDE configurations

The 2007 QNDE ultrasonic benchmark session involved researchers from four different institutions around the world. The two studies they considered examined the influence that the curvature of a cylindrical fluid‐solid interface has on the measured NDE immersion test response of a flat‐bottom hole (FBH) reflector. The first study was a model‐based study of the effects of different FBH sizes and curvatures, where the FBHs were all located a specific depth in a solid. The second study compared model‐based predictions with experiments for different interface curvatures and a FBH hole of a fixed size but located at different depths. Here, we will summarize the results obtained and analyze the differences between the different models and between the model‐based results and the experiments.

2007 ultrasonic benchmark studies of interface curvature—a summary

This paper presents some applications of ultrasonic (UT) simulation codes developed at IZFP, Germany and at CEA LIST, France, those latter being integrated into the CIVA software platform These UT simulation codes are dedicated to the prediction of echo‐responses from flaws Results given and discussed are those obtained for the various problems of the 2007 UT Benchmark modeling session They concern the responses from flat‐bottomed holes inside curved blocks (concave or convex) inspected with immersed probes The simulation codes are used to investigate the influence of the curvature upon the amplitude response of the flaw with respect to a flat specimen, used as a reference Comparison with experimental results is also discussed

S. Chatillon

Papers

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

Recent advances and current trends of ultrasonic modelling in CIVA

Simulation of phased array techniques for realistic NDE configurations

2007 ultrasonic benchmark studies of interface curvature—a summary

Results of the 2007 ut modeling benchmark using two semi‐analytical beam propagation and flaw scattering model