Socpra Sciences Et Genie S.e.c.

Centre National De La Recherche Scientifique

Université De Poitiers

Abzac Canada Inc.

Scopra Sciences Et Génie S.e.c.

Patrice Masson

Nicolas Quaegebeur

Alain Berry

Pierre-Michel D'Anglade

Philippe Micheau

Yves Gervais

Philippe Sarret

Cédric Ardin

Pierre-Claude Ostiguy

Nicolas Beaudet

Dominique Langlois Demers

Anthony Gerard

Michel Besombes

An in-line, contactless and non-destructive method for detecting and identifying defects in a moving cardboard structure is provided, as well as the associated system. The cardboard structure is of the type made of layered paper plies, such as cardboard tubes for example. The method includes the steps of emitting acoustic waves with predetermined frequencies toward the moving cardboard structure. The acoustic waves are converted into mechanical waves propagating through the moving cardboard structure. The method also includes a step of capturing the acoustic waves propagated, wherein said captured acoustic waves result from a conversion of the propagated mechanical waves through the moving cardboard structure. The method also provides steps of analyzing the captured acoustic waves; and detecting and identifying defects in the moving laminated cardboard structure based on predetermined propagation properties measured from the captured acoustic waves.

In-line, contactless and non-destructive method and system for detecting defects in a moving cardboard structure

Method and apparatus for determining that a pressure field is applied on a structure. A plurality of acoustic waves are generated within the structure using at least one wave generator and a plurality of measurements of the acoustic waves is taken using at least one wave sensor. A pressure field applied to a surface of the structure is determined by processing at least two of the plurality of measurements. The wave generator and the wave sensor may be piezoelectric elements, which may alternate between acting as the wave generator and the wave sensor. Processing the measurements may comprise obtaining a differential measurement value and comparing the value to a threshold. Determining that the pressure field is applied may comprise processing the measurements using a model based on acoustic wave propagation or experimental results. The processing may provide a mapping of the pressure field of an object on the structure.

Active acoustic pressure mapping system

The invention relates to a method for providing a structural condition of a structure, comprising providing an excitation wave generator; providing an excitation wave sensor; injecting an excitation burst wave into the structure using the excitation wave generator; obtaining a measured propagated excitation burst wave using the excitation wave sensor; correlating the measured propagated excitation burst wave with one of a plurality of theoretical dispersed versions of the excitation burst wave; and providing an indication of the structural condition of the structure corresponding to the correlated measured propagated excitation burst wave. The method may offer a better localization of the reflection points and thus of the potential defects present in a structure under inspection, when compared with a group velocity-based or time-of-flight (ToF) approach. The method may be particularly useful for structural health monitoring (SHM) and Non-Destructive Testing (NDT). The method may also enable determination of the mechanical properties of the structure.

Method and apparatus for providing a structural condition of a structure

A method and apparatus for reducing a selected tonal noise generated by a fan operating in a non-uniform flow by locating at least one obstruction in the non-uniform flow such that the at least one obstruction generates a noise that is out of phase with the selected tonal noise. The noise generated by the at least one obstruction interferes with the selected tonal noise, thus reducing the selected tonal noise. It is also contemplated to use additional obstructions to reduce other tonal noises generated by the fan.

Method and apparatus for controlling tonal noise from subsonic fans

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Sherbrooke, Canada

Patrice Masson