Marie-Aude Ploix

POTENTIAL OF ULTRASOUNDS FOR NDT OF A STRUCTURE LOCATED BEHIND PARALLEL IMMERSED PLATES

The in‐service inspection (ISI) of internal structures in future liquid sodium‐cooled fast reactors is studied in‐depth by the CEA. Among the different options available, ultrasounds from outside the sodium circuit can be used for this purpose. The need to propagate the maximum energy possible orientated the study towards Lamb waves. This study aims at controlling ultrasonic propagation in these multilayered structures in order to determine the best conditions for the NDT of a plate behind n screens.

Non destructive measurement data fusion for a better assessment of concrete

Non destructive techniques provide many quantitative information about concrete condition (observables), which must be processed such as to give way to the indicators which are looked for. An experimental database is defined and fed with a series of NDT measurements obtained through various techniques. The methodology requires: the selection of best observables, the expression of relationships between indicators and observables and the combination of information provided by various sources. Data fusion, which accounts for uncertainties arising at various levels, offers a promising way.

Combiner et fusionner les mesures de CND pour mieux estimer les propriétés du béton

ABSTRACT Non destructive techniques provide many quantitative information about concrete condition (observables), which must be processed such as to give way to the indicators which are looked for. An experimental database is defined and fed with a series of NDT measurements obtained through various techniques. The methodology requires: the selection of best observables, the expression of relationships between indicators and observables and the combination of information provided by various sources. Data fusion, which accounts for uncertainties arising at various levels, offers a promising way.

Study of acoustoelasticity behavior of concrete material under uniaxial compression

The general subject concerns the non destructive testing of pre-stressed structure in civil engineering structures. In this topic we interest in the faisability of stress evaluation in concrete by ultrasonic methods. To do that, we use the acoustoelasticity theory which exploits the nonlinear behaviour of medium to establish the link between stress and ultrasonic velocity. This theory had been validated in homogeneous media and used in steel to evaluated stresses in steel bolt for example. The concrete is a heterogeneous medium where the ultrasonic velocity measurement is more difficult than in steel. The scattered waves induce uncertainty in the measured values but the nonlinear behaviour of concrete is more important than the one of steel. We show an application in high performance concrete submitted to uniaxial compression. We measured velocities of longitudinal and transversal transmitted ultrasonic waves in the direction of the stress and perpendicular to the stress at different stage of the stress test. The sensibilities of the velocities are observed and the potential to evaluate stress in concrete in shown. The prospect concern the widening of formulation tested and the in situ measurements. This study is supported by ANR-ACTENA, a french research program.The general subject concerns the non destructive testing of pre-stressed structure in civil engineering structures. In this topic we interest in the faisability of stress evaluation in concrete by ultrasonic methods. To do that, we use the acoustoelasticity theory which exploits the nonlinear behaviour of medium to establish the link between stress and ultrasonic velocity. This theory had been validated in homogeneous media and used in steel to evaluated stresses in steel bolt for example. The concrete is a heterogeneous medium where the ultrasonic velocity measurement is more difficult than in steel. The scattered waves induce uncertainty in the measured values but the nonlinear behaviour of concrete is more important than the one of steel. We show an application in high performance concrete submitted to uniaxial compression. We measured velocities of longitudinal and transversal transmitted ultrasonic waves in the direction of the stress and perpendicular to the stress at different stage of the stress t...